Remedial Investigation Report Volume 1 - Text and Figures · Durin angd 1993 199 EP2, A conducte ad limited investigation throug thhe Superfund Technical Assessmen &t Response Team

Gallups Quarry Superfund Project Plainfield Connecticut

SDMS DocID 3934 Project No 7194138

Remedial Investigation Report Volume 1 - Text and Figures

submitted to

US EPA - Region I Boston Massachusetts

DRAFT MARCH 15 1996 FIRST REVISION AUGUST 9 1996

SECOND REVISION OCTOBER 22 1996 FINAL JUNE 1997

ENVIRONMENTAL Formerly Environmental Science amp Engineering Inc

410 Amherst Street Nashua NH 03063 Telephone (603) 889-3737

GENERAL

Volume 1

Volume 2

Volume 3

Volume 4

Volume 5

Volume 6

Volume 7

Gallups Quarry Superfimd Project - Remedial Investigation

TABLE OF CONTENTS

Text and Figures

Tables

Plates

Appendices A B C D E Famp G

Appendices H I J amp K

Appendices L M amp N

Appendices O P Q R S T U amp V

5797wpdoc8galluprifinaltextrigentoc061397 QST Environmental

Remedial Investigation

Gallups Quarry Superfund Project

Plainfield Connecticut

Submitted to

US EPA - Region I

Boston Massachusetts

Prepared by

QST Environmental

(formerly Environmental Science amp Engineering Inc)

Nashua New Hampshire

June 1997

QST Project No 71941380430

Gallups Quarry Superfund Project - RI Executive Summary

Executive Summary

EI Purpose of the Report This document presents the Remedial Investigation (RI) Report which was completed for the

Gallups Quarry Superfund Site (Site) pursuant to the requirements of US Environmental Protection Agency (EPA) Administrative Order by Consent Docket Number 1-93-1080 (Order)

issued September 7 1993 The Site is a former sand and gravel quarry and is located on Tarbox

Road in the Town of Plainfield Connecticut (see Figure E-l) The Study Area includes the Site

as well as areas west and north of the Site

Investigation of the Site was initiated in 1978 when unlicensed waste disposal operations were

discovered at the property Emergency clean-up operations were conducted in three disposal

areas by the Connecticut Department of Environmental Protection (CTDEP) in April 1978

(Metcalf amp Eddy 1993) Following the initial clean-up effort a series of surface and subsurface

sampling events were performed by the CTDEP the Connecticut Department of Health (CTDOH) and US Environmental Protection Agency (EPA) Based primarily on the detection of

groundwater contamination the Site was listed on the National Priorities List (NPL) on October 4 1989 During 1992 and 1993 EPA conducted a limited investigation through the Superfund

Technical Assessment amp Response Team (START) initiative in an effort to expedite the

completion of the Remedial InvestigationFeasibility Study (RIFS) The requirements of the

Order as well as data included in the START report (Metcalf amp Eddy 1993) provided the

framework for the Remedial Investigation

This RI Report is the sixteenth major deliverable under the Order The first major deliverable

the Remedial InvestigationFeasibility Study Work Plan - Phase 1A was finalized and submitted to EPA on August 29 1994 QST Environmental (formerly Environmental Science amp Engineering Inc (ESE)) finalized the Work Plan and has prepared all of the other deliverables

The Phase 1A field investigation was completed in January 1995 The second major deliverable

the Phase 1A Data Report dated March 24 1995 was submitted to EPA following completion of

the Phase 1A field investigation The findings of the Phase 1A Investigation were described in

the Initial Site Characterization Report (ISCR) which was finalized and submitted to EPA on

March 1 1996 A Work Plan for the Phase IB field investigation was finalized and submitted on

October 11 1995

In addition to the Phase 1A field investigation the Phase 1A Work Plan also described the Long-

Term Monitoring Program which was initiated upon completion of the Phase 1A field

investigation The Long-Term Monitoring Program includes the quarterly collection and analysis

of groundwater and semi-annual collection and analysis of surface water and nearby residential

well samples The Phase IB field investigation commenced on October 12 1995 Following the

5797wpdocsglaquollupfsfinlaquoltextexecnimmri060997 E-l QST Environmental

SOURCE PLAINFIELD CONNECTICUT QUADRANGLE USGS TOPOGRAPHIC MAP 75 MINUTE SERIES 1983

410 Amherst Street 124000 Nashua NH 03063

(603) 889-3737

0 GALLUPS QUARRY SUPERFUND PROJECT

PLAINFIELD CONNECTICUT SCALE IN MILES REMEDIAL INVESTIGATION REPORT

comacncur FIGURE E-l

SITE LOCATION MAP DRAWING NAME ELOCDWG FILE NUMBER 7194-138

QUADRANGLE LOCATION

SCALE AS SHOWN REVISION 0 I DRAWN BY PAP [DATE 5997

Gallups Quarry Superand Project - RI Executive Summary

completion of drilling activities the Phase IB groundwater sampling task and the fourth quarter

1995 Long-Term Monitoring sampling event were performed simultaneously in November 1995

Seven Data Reports have been submitted to the EPA for the following Long-Term Monitoring

Program sampling events the second and third quarters of 1995 all four quarters of 1996 and

the first quarter of 1997 (ESE 1996a 1996b 1996c 1997a 1997b) The draft RI Report was

submitted to EPA on March 15 1996 (and revised and resubmitted October 22 1996) and included the results of the fourth quarter of 1995 sampling event On March 29 1996 the

following two deliverables were submitted to EPA Development and Initial Screening of Alternatives Report and Detailed Analysis Work Plan The draft Feasibility Study was submitted

to EPA on January 27 1997 This RI Report describes the methods and findings of both the Phase 1A and IB field studies and includes data collected during the April July and November

1995 February May August and November 1996 and February 1997 Long-Term Monitoring

sampling events

E2 Site Background E21 Area Description

The 29-acre Gallups Quarry Site is located on the north side of Tarbox Road in the Town of

Plainfield Windham County Connecticut The Site which is currently vacant is bounded by

wooded areas and wetlands associated with Mill Brook (which flows from east to west

approximately 250 feet north of the Site) single-family residences and several commercial

properties Approximately 700 feet north of the Site on the opposite side of Mill Brook is an industrial park which contains an Intermark Fabric Corporation facility (formerly the Pervel

Industries flock plant) and a Safety Kleen Corporation accumulation facility Further north of the

industrial park are several presently vacant mill buildings which were previously occupied by various manufacturers including Pervel Industries and the InterRoyal Corporation The Plainfield sewage treatment plant which discharges to Mill Brook and its major tributary (Fry Brook) is

located approximately 1800 feet northwest of the property

E22 Site Operational History

Limited information is available regarding the early operational history of the Site Historical

aerial photographs and records at the Town of Plainfield Assessors office indicate that in 1951

the Site was owned by a Mr Johnson and that some quarrying activities were underway in the

southern portion of the Site In 1964 the Site was purchased by C Stanton Gallup Although

detailed usage of the Site from 1964 through 1977 is poorly documented records indicate that the

Site was used as a source of aggregate and was occupied by the Connecticut Department of

Transportation (CTDOT) who were operating an asphalt batching plant

5797WTgtdocsgallupfsfinltextexec8ummri060997 E-3 QST Environmental


As a result of complaints from neighboring residents the CTDEP and the Connecticut State

Police initiated an investigation of the Site in January of 1978 The CTDEP investigation

concluded that the Site was used from the summer of 1977 until December 1977 for unlicensed

waste disposal Evidence collected by CTDEP indicates that Chemical Waste Removal Inc

(CWR) of Bridgeport Connecticut transported drummed and bulk liquid waste material to the

Site These materials reportedly included a variety of industrial wastes

Emergency clean up efforts were performed during the summer of 1978 under the direction of the

CTDEP and the Connecticut State Police This involved the removal and off-site disposal of

1584 drums 5000 gallons of free liquid and 2277 cubic yards of contaminated soil from three

distinct locations on the Site The drums as well as liquid waste and contaminated soil were

removed from the Primary and Secondary Disposal Areas located in the northern portion of the

Site Remedial measures performed at the Seepage Bed reportedly located in the central portion

of the Site included the excavation of contaminated soil and in-situ treatment of remaining soils

through the addition of 20 tons of lime A buried inverted dump truck body was also reportedly

removed from the Site In addition to these remedial activities mine detectors were utilized to search for additional buried drums There was no evidence of additional buried drums and it

was believed that all drums were recovered during the cleanup operations

Since the 1978 cleanup operations the Site has been vacant although there are some indications

that the Site has been utilized by trespassers for recreational purposes

E23 Summary of Previous Investigation

ations and sampling events were conducted at the Gallups Quarry Site The significant previous

investigations are as follows

bull A general site investigation performed on behalf of the State of Connecticut (Fuss amp

ONeill 1979) which included the installation of 22 monitoring wells 19 test pits (13

of which were completed as shallow monitoring wells) and the collection of surface

water and sediment samples The investigation was completed within several months

of the States remedial efforts described above Groundwater from monitoring wells

and nearby residential wells as well as surface water from Mill Brook was sampled

several times from the period of July to December 1978

bull Various CTDEP monitoring events for groundwater surface water and sediment

occurred from 1979 until 1993 Sampling events were conducted in October 1979

January and November 1980 April and October 1981 April 1982 and December

1983 CTDEP also performed a biodiversity survey in 1985 in an effort to evaluate

potential impacts to the Mill Brook wetland In addition CTDEP also conducted

sampling anq (analysis of neighboring residential wells in 1992 and 1993

5797wpdocraquogallupf8finlaquoltextexecsummri060997 E-4 QST Environmental

Gallups Quarry Superjund Project - RI Executive Summary

bull A Hazard Ranking System (HRS) Study was completed in 1987 by NUS Corporation

foi ZPA The Study included the collection of water samples from two existing

moiiitoring wells and three surface watersediment locations

bull A review of historic aerial photographs of the Study Area was performed by the

Bionetics Corporation on behalf of the EPA Photographs dating back to 1951 were

included in the review which was published in 1990 (Bionetics Corp 1990)

bull In cooperation with EPA the USGS performed a geohydrologic investigation at the

Study Area in 1993 This investigation included geophysical surveys (EM-34 and GPR) to characterize various subsurface features One monitoring well was installed

bull In 1993 the US Fish and Wildlife Service performed a field study to characterize the

habitats within the Study Area The study was finalized in 1995

bull Various sampling events were conducted in 1989 and 1993 on behalf of the EPA During these sampling events groundwater from existing monitoring wells and nearby

residential wells as well as surface soil samples were collected for analysis

The significant findings of these investigations are summarized as follows

bull The initial study completed at the Site by Fuss amp ONeill in 1979 concluded that

groundwater in the vicinity of the former disposal areas had been impacted by certain

volatile organic compounds (VOC) and metals A well-defined groundwater plume which contained these various constituents extended in a northwest direction away

from the Site

bull Periodic CTDEP sampling events from 1979-1982 indicated the wells downgradient of

the former disposal areas consistently showed detectable levels of constituents similar

to those disposed of on-site The results of CTDEP sampling events indicated that

nearby residential wells had not been impacted by the Site

bull The USGS study provided an updated geological characterization of the Study Area

and suggested the potential presence of a bedrock fault zone located in the vicinity of

the Former Seepage Bed

bull The results of the 1989 and 1993 sampling events generally confirmed the findings of

previous groundwater quality investigations and indicated that VOC concentrations

decreased significantly in the period between 1982 and 1993

5797wpdocgglaquollupfsfiiultextexecnjmmri060997 E-5 QST Environmental

Gallups Quarry Superfiotd Project - RI Executive Summary

To supplement historical data and data obtained during the Phase 1A field program a CTDEP file

search was performed to obtain information pertinent to groundwater contamination for industrial

properties neighboring the Site The available information indicates that

bull two separate companies Pervel Industries and InterRoyal Corporation operated

manufacturing facilities at locations approximately 2500 feet north of the Site

bull Pervel Industries also maintained a second facility (a fabric flock plant) located

approximately 1000 feet north of the Site across Mill Brook

bull there have been documented releases of 111-trichloroethane (TCA) and toluene at

the northern-most Pervel plant

bull contaminated soil and sediment associated with a 1985 spill of 111-TCA at the

northern-most Pervel facility was stored in an impoundment located on the eastern

(upgradient) side of the Pervel flock plant property

bull the contaminated soilsediment impoundment was located approximately 1000 feet

from the northern end of the Site

bull the results of historical groundwater monitoring at the former Pervel flock plant

located a few hundred feet north of the Site show the presence of elevated

concentrations of several VOC including tetrachloroethene (PCE) and TCA

E3 Summary of Remedial Investigations Phase 1A Field Investigations

In order to maximize the efficiency of the Site characterization program for the Gallups Quarry

Site multiple phases of data collection and evaluation were performed during the Phase 1A field

program Screening level surveys completed during the initial weeks of the field program

utilizing fast-turnaround data generation and evaluation techniques were used to focus data

collection efforts during the latter part of the Phase 1A field program The screening surveys

included

bull A visual site reconnaissance involving transit by foot and direct observations and

photographic documentation of significant features along approximately 39000 feet of

trend lines covering the entire Site

bull Geophysical surveys including electromagnetic terrain conductivity (EM) and

magnetometer surveys along 25-foot spaced trend lines totalling approximately

5797wpdocBgallupf8finaltextexeclaquoummri060997 E-6 Q5T Environmental

Gallups Quarry Superfimd Project - Rl Executive Summary

39000 feet in length and covering the entire Site follow-up EM-31 and

magnetometer surveys and a test pit program in three areas where anomalies were

observed and a seismic refraction survey west of the Former Seepage Bed

bull A microwell survey which included the collection of 126 groundwater samples from

multiple depths at 50 locations within the Study Area field gas chromatograph

analyses of all of these samples for an indicator list of 8 VOC laboratory analyses of

121 of these samples for metals and 12 of the samples for VOC and

bull A soil vapor survey which involved the collection of soil vapor samples from 106

locations throughout the Site and on-site analyses for an indicator list of 8 VOC

Based on these screening level and historical data a groundwater monitoring well installation

sampling and analytical program was designed The program as approved by EPA included the

following

bull The installation of 5 wells at 2 designated background locations These wells include

a shallow overburden and a bedrock well in the northern portion of the Site and two

overburden wells (screened at the water table and in a deeper till horizon) and a

bedrock well in the southern portion of the Site Background soil and groundwater

samples were collected from these locations

bull The installation of 19 wells at seven locations downgradient (northwest) of the Former

Primary and Secondary Disposal Areas to assess and define the boundaries of a

contaminant plume identified during the microwell survey These wells included 17

overburden wells and two bedrock wells

bull The installation of six wells at three locations located north and east of the Former

Primary Disposal Area to assess groundwater quality and flow directions in these

areas These wells included five wells screened in overburden and one in bedrock

bull The installation of two bedrock wells and one overburden well at two locations in the

vicinity of the Former Seepage Bed This included one bedrock well placed within an

inferred bedrock faultfracture zone to assess the zones potential to act as a preferred

contaminant transport pathway

bull The installation of five wells at two locations in the southern portion of the Site to

assess very limited screening-level VOC detections in this portion of the property

These wells include four overburden wells (two shallow and two top-of-till) and one

5797wpdoclaquoglaquollupftfinlaquolte)rtexecraquoummri060997 E-7 QST Environmental


bedrock well In addition six groundwater piezometers were installed to assess groundwater flow directions in the southern portion of the Study Area gtmdashr

Samples from three of the newly installed wells (MW102TT MW106TT and MW116T) were analyzed for Appendix IX parameters Samples from the remaining newly installed monitoring wells and three existing wells (SW-9 SW-10 SW-12) were analyzed for Target Analyte ListTarget Compound List (TALTCL) parameters Twelve nearby residential wells were also sampled for TALTCL parameters (although VOC were analyzed using EPA method 5242) In addition to the monitoring well installation and groundwater sampling program outlined above the following tasks were performed during the Phase 1A field program

bull Air quality monitoring to establish ambient air quality prior to and during the intrusive investigations A total of eight air monitoring stations were established at locations within and at the Site perimeter

bull Water-level measurements were recorded to assess horizontal and vertical groundwater flow directions and aquifer testing (including evaluations of the remaining existing monitoring wells) using slug tests was conducted to assess the hydraulic conductivity of the aquifer

bull Soil boring programs within the three known disposal areas to assess the nature and extent of residual contamination A total of ten soil borings were completed at the three areas Each boring was continuously sampled and terminated at auger refusal Selected samples were submitted for laboratory analysis for TALTCL parameters based on lithology depth and photoionization detector (PID) headspace readings as set forth in the Work Plan

bull Surface watersediment sampling was performed at 17 locations including Mill Brook Fry Brook Packers Pond and in an unnamed pond on Tarbox Road just south of the entrance to the Site In addition wetland soil samples were collected from 10 locations within the Study Area All samples were submitted for analysis for TALTCL parameters

bull Federal and State jurisdiction^ wetland delineations were performed

Phase IB Field Investigations The data collected during Phase 1A was supplemented with the following additional investigative activities conducted during the Phase IB field investigation

5797wpdocsgallupfsfiMltextexecsummri060997 E-8 QST Environmental


bull Quantitative air monitoring for site-specific compounds in the vicinity of the Former

Prirary Disposal Area

bull Collection and analysis of soil samples from six additional soil borings in the Former

Primary Disposal Area to more fully characterize the extent of residual VOC and PCB

contamination

bull The installation of seven additional groundwater monitoring wells and one additional

piezometer to obtain additional groundwater data from the downgradient portion of the

plume and from the northnorthwest portion of the Site The monitoring wells

included (3) two well clusters and (1) bedrock well

bull Collection of groundwater samples from each new monitoring well and from five

existing wells on the former Pervel facility and analysis of these samples for VOC to confirm the downgradient extent of the plume originating in the Former Primary

Disposal Area and

bull The performance of constant flow tests consisting of short-term pumping tests on selected groundwater monitoring wells to supplement Phase 1A hydraulic conductivity

data so that groundwater velocities and transport rates and aquifer yield could be

more accurately determined

Long-Term Monitoring Program

A Long Term Monitoring Program was initiated upon completion of the Phase 1A field investigation The Long-Term Monitoring Program includes the quarterly collection and analysis


well samples Data from eight quarterly sampling rounds (performed in April July and

November 1995 February May August and November 1996 and February 1997) are presented

and discussed The Conceptual Model discussion is based on the 1995 quarterly sampling rounds

Any minor adjustments to the Conceptual Model resulting from later monitoring rounds are

addressed in the FS

E4 Conceptual Model of the Study Area E41 Physical Characteristics E411 Physiography

The Site is located along the eastern border of the Quinebaug Valley Lowland The region is

characterized by relatively low relief and numerous glacial features The regional landscape is

5797wpdoc8glaquollupfBfinaltextexecraquoummri060997 E-9 QST Environmental


significantly influenced by the structure of the underlying crystalline metamorphic bedrock The

topography of the Site is highly irregular primarily due to past quarrying operations including

numerous overgrown mounds of earthen materials and excavated depressions The ground

surface on the Site generally slopes from the east to the west and to a large degree is controlled by the underlying bedrock surface North and west of the Site the ground surface elevation

decreases in the Mill Brook floodplain which is described as a low lying heavily vegetated

wetland

E412 Geology

The overburden deposits in the area consist of materials deposited as a result of glacial processes during the Pleistocene epoch A range of glacially-derived materials including till meltwater or

stratified drift deposits and post-glacial deposits of floodplain alluvium comprise the major

surficial geologic units in the vicinity of the Site The significant surficial deposits encountered

within the Study Area during the RI are till and stratified drift Stratified drift deposits can be

further broken down into coarser-grained or finer-grained components The Study Area is

dominated by coarser-grained deposits which represent various ice-contact or outwash features associated with the retreat of the ice-mass Finer-grained components also exist to a limited

extent within the Study Area and are the result of lacustrine deposition which occurred when

low-lying areas were inundated by a glacial lake Much of the Sites overburden geology

represents the transition of depositional environments as the glacier progressively retreated from

the area Although alluvial floodplain deposits were encountered at locations within the present

Mill Brook floodplain the significance of these deposits is minor

The thickness of the stratified drift deposits range from non-existent in the vicinity of bedrock

outcrops in the eastern portion of the Site to approximately 70 feet The overburden thickness

increases in response to a decrease in the elevation of the bedrock surface Till was encountered just above the bedrock surface at nearly every location The till horizon ranges in thickness from

approximately 10 to 20 feet with the thickest accumulations located along bedrock highs

Surficial exposures of glacial till were observed on the Site The till is relatively dense and is

comprised of a fine sandy matrix with abundant gravel cobbles and boulders

Bedrock in the vicinity of the Site mapped as a lower member of the Quinebaug Formation

consists of hornblende gneiss biotite gneiss and amphibolite and is strongly faulted and folded

exhibiting varying degrees of mylonitization Geophysical surveys performed prior to and during

the Phase 1A field program indicate that a northwest-trending fracture zone may extend across the

central portion of the Site Based on the drilling program depths to bedrock range from zero to

83 feet below ground surface within the Study Area Bedrock elevations are greatest in the

eastern central portion of the Site and decrease to the north and west and to a lesser degree to

the south

5797wpdocsgallupfsfinaltextexecsummri060997 E-10 QSTEnvironmental


E413 Hydrogeology

E4131 Hydraulic Conductivity

The hydraulic conductivity distributions within the overburden and bedrock formations were

evaluated through the performance of constant flow (pumping) tests and rising and falling head

slug tests Hydraulic conductivity measurements indicate that coarse-grained stratified drift

deposits in the lower portion of the aquifer are the most permeable subsurface materials in the Study Area with a mean hydraulic conductivity of 0005 centimeters per second (cms) The

highest hydraulic conductivities were found in the lower portion of the aquifer northwest of the Former Primary Disposal Area where the mean hydraulic conductivity is 0037 cms The mean

hydraulic conductivity of the finer-grained deposits in the upper portion of the aquifer is about

0001 cms

The mean hydraulic conductivity for the till wells (000047 cms) is a factor of ten less than the

average value for coarse stratified drift and varies between 00002 cms and 0002 cms The till

appears to be hydrogeologically distinct from the other overburden deposits and on the average

provides increased resistance to groundwater flow This added resistance is not considered to be

significant however because the consistency of the till and overburden deposits are highly

variable and the hydraulic conductivity contrast is relatively small The slug test results for the

bedrock wells yield the lowest (000018 cms) average hydraulic conductivity

E4132 Groundwater Flow

Horizontal Flow

Overburden groundwater flow south of the Former Seepage Bed is primarily east to west and is

influenced by two factors (1) the slope of the bedrock surface which defines the base of the

unconsolidated deposits and (2) regional hydrologic drainage patterns The average east-west horizontal hydraulic gradient in the southern portion of the Study Area is approximately 001 feet

per foot (feet change in piezometric head per horizontal foot of distance)

In the northern portion of the Study Area three hydrogeologically distinct zones exist South of the Former Primary and Secondary Disposal Areas the hydraulic gradient is steep (approximately

003 feet per foot) and is strongly influenced by the dip of the bedrock surface (01 feet per foot)

The saturated thickness increases from zero south of well MW109 to about 20 to 30 feet near the

former disposal areas North-northwest of the former disposal areas the hydraulic gradient

lessens significantly to a range of 00003 to 00007 feet per foot representing a factor of 40 to

100 reduction North-northeast of Mill Brook the hydraulic gradient is about 0007 feet per foot

Available data indicate that currently northwest of the railroad tracks groundwater flow in the middle to lower portions of the aquifer converges from the northeast and southwest toward a

centerline area generally defined in the downgradient direction by wells MW105 MW102 and

5797wpdoclaquoglaquoliupfraquofirultextexeclaquoummri060997 E-ll QST Environmental


MW101 The flow direction near these wells is from the former disposal areas to the northwest

Northeast of this centerline groundwater flows in a southwesterly direction from the vicinity of

Mill Brook and the former Pervel flock plant North of Mill Brook and west of the railroad

tracks the predominant groundwater flow direction becomes more westerly

No significant seasonal changes in horizontal groundwater flow directions were observed in the

Study Area Groundwater levels were generally highest in January 1995 and decreased by about

two feet through the period ending on July 11 1995 Levels then increased by about one foot

from July to November

General overburden groundwater pathlines for the northern portion of the Site are shown on

Figure E-2

Groundwater in bedrock moves primarily in a westerly direction south of the Former Seepage

Bed while in the northern Study Area the predominant bedrock flow component is toward the

northwest In both areas the hydraulic gradient is on the order of 002 feet per foot Groundwater in bedrock near the Former Seepage Bed flows to the northwest and exhibits no apparent

influence from the locally identified fracture zones

Vertical Flow

Vertical flow of groundwater is an important component in the upper several feet of the bedrock

unit Water level measurements indicate that groundwater is discharging from bedrock into the

overburden at every location measured except MW109 In most clusters the vertical hydraulic

gradient between bedrock and overburden is an order of magnitude greater than the horizontal

gradient

In the overburden aquifer the downward vertical flow component is significant within shallow

deposits near the Former Primary Disposal Area (wells MW107 MW108 and MW116) and the

upward flow is important in the upper portion of the aquifer near Mill Brook The downward

groundwater flow within the Former Primary Disposal Area appears to be primarily associated

with infiltration of precipitation and collection of surface water runoff from upland areas This

causes VOC concentrations to be highest in the middle to lower portions of the aquifer Stream

5797wpdocsgallupftfinaltextexecsummri060997 E-12 QST Environmental

N

LEGEND

WATERCOURSE

PROPERTY BOUNDARY

bullPIEZOMETRIC HEAD CONTOUR LOWER PORTION OF AQUIFER NOVEMBER 6 1995 (FEET)

GROUNDWATER PATHLINE

NOTES

1 BASE PLAN PROVIDED BY USEPA DRAWING NO 707600 DATED 14 OCTOBER 1993

2 HORIZONTAL DATUM - CONNECTICUT STATE PLAN COORDINATE SYSTEM NORTH AMERICAN DATUM OF 1927

3 PROPERTY BOUNDARIES OBTAINED FROM TOWN OF PLAINFIELD TAX ASSESSORS OFFICE

400 400 800

SCALE IN FEET

410 Amherst Street Nashua NH 03063

(603) 889-3737 UmHOHHM

GALLUPS QUARRY SUPERFUND SITE PLAINFIELD CONNECTICUT

REMEDIAL INVESTIGATION REPORT

FIGURE E-2

SJjTff WIDE GROUNDWATER FLOW DRAWING NAM6 RIWIDEFWDWG FILE NUMBER 7194 138

SCALEAS SHAWN REVISION 1 DRAWN BY DJB DATE 5997

Gallups Quarry Superfiind Project - RI Executive Summary

piezometer data and groundwater flow modeling indicate that Mill Brook generally gains water

from the overburden aquifer within the Study Area

E414 Ecology

Wetlands delineations were performed to the extreme northern and western boundaries of the

Study Area up to the Mill Brook channel using both the State of Connecticuts accepted criteria

(which focuses on soil types and hydric soil characteristics) and the Federal criteria using US

Army Corps of Engineer methods (which includes the examination of vegetation hydrology and

soils) Most of the wetlandupland boundary occurs along the edge of a steep grade The sharp

relief produces a narrow transition between uplands and wetlands The delineated lines reflect

this as the State and USACOE wetland boundaries coincide at nearly every location With the

exception of an area intersecting a small portion of the Site at the northernmost edge of the

property east of the former disposal areas no wetland areas were identified on the Site

A preliminary identification of plant and animal species present in the Study Area was conducted during the wetlands delineation A limited number of wildlife species were observed Numerous

plant species were identified over the heavily vegetated Study Area No endangered species were

observed nor are reported to reside in the Study Area

E42 Nature and Extent of Contamination

E421 Contaminant Source Investigation The following summarizes the findings of contaminant source investigations conducted during the

RI program

bull Previous remedial activities have completely removed the waste materials (intact drums and bulk liquid waste) from the Site

bull The Former Seepage Bed and the Former Secondary Disposal Area contain

little residual contamination from the disposal activities which occurred in the

late 1970s

bull Residual levels of contamination primarily VOC and PCB were measured in

the Former Primary Disposal Area In general the highest levels of VOC are

located at or just below the groundwater table in native soils immediately

beneath the fill materials and diminish rapidly with depth Low levels of

PCB were detected primarily within shallow fill materials

5797wpdocraquogallupftfinlaquoltextexecraquoummri060997 E-14 QST Environmental

Gallups Quarry Superfiutd Project - Rl Executive Summary

bull Other than the three known former disposal areas and the remains of a

former CTDOT asphalt plant no other disposal areas were found to exist on -

the Site

E422 Groundwater Quality

Groundwater quality data collected during the Remedial Investigation indicate the following

bull No significant groundwater contamination was detected within the overburden

or bedrock units in either the southern Study Area or in the vicinity of the

Former Seepage Bed

bull In the northern Study Area a narrow low to moderate-concentration VOC

plume was detected in the overburden aquifer extending from the vicinity of

the Former Primary Disposal Area to the northwest towards Mill Brook

TCA and DCE were consistently detected at all locations along the plume

centerline at concentrations as high as 240 ppb and 1300 ppb respectively

bull Comparison of present concentrations with historical data indicate that VOC

levels are significantly decreasing with time From 1978 through 1995 TCA

TCE and PCE concentrations have decreased on the average by more than a

factor of two every two years representing environmental half-lives of less

than two years

bull The size and orientation of the plume are in excellent agreement with the

established groundwater flow directions

bull Available information indicates that the leading edge of the VOC plume

associated with the Former Primary Disposal Area is located in the vicinity of

monitoring well clusters MW-102 and MW-101 Concentrations of TCA and

DCE reduce to below MCLs at MW-101 Contaminant migration rates also

support this delineation of the front of the site-related VOC plume

bull Increasing PCE detections in the downgradient portion of the plume exhibit

inconsistencies with calculated migration rates from the Site Groundwater

flow directions VOC transport rates and historical concentration trends

indicate that PCE detections in wells MW118 MW116 MW103 MW118

MW102 and MW101 may be associated with contaminant transport from the

former Pervel flock plant However it is also possible that the PCE

detections at locations MW102 and MW101 are attributable to the former

disposal areas In addition contaminated groundwater from Pervel may have

5797wpdocsgal]upfraquofinaltextexeclaquoummri060997 E-15 QST Environmental


also contributed TCA TCE DCE and vinyl chloride to the site related VOC

plume

Results of surface watersediment sampling and analyses stream piezometer measurements and groundwater flow modeling indicate that some discharge

of the shallow portion of the plume into Mill Brook is occurring However

the concentrations of VOC detected in the brook are well below those

reported to cause adverse effects in fish or wildlife

Bedrock is not considered a preferred pathway for contaminant migration due

to its characteristically low hydraulic conductivity and the predominantly

upward component of groundwater flow from bedrock to overburden which

exists throughout the Study Area

5797wpdocsgallupftfinlaquoltcxtexec8ummri060997 E-16 QfT Environmental

Gallups Quarry Superfund Project - Remedial Investigation

Table of Contents

Section Page

10 Introduction bdquo 1-1

11 Purpose of the Report 1-1 12 Report Organization 1-2

13 Site Background 1-3 131 Area Description Demography and Land Use 1-3 132 Operational History 1-5

133 Summary of Previous Investigations 1-7

20 Field Investigations 2-1

21 Site Survey 2-1

211 Initial Site Survey 2-1

212 As-Installed Survey 2-1

22 Site Reconnaissance 2-2

221 Visual Observations of the Ground Surface 2-2

222 Air Quality Survey 2-2

223 Exclusion Zone Identification 2-4

224 Project Support Measures 2-4

225 Identification of Sensitive Human Receptors 2-5

23 Geophysical Surveys 2-5

231 Electromagnetic Terrain Conductivity (EM) Survey 2-7 232 Magnetometer (MAG) Survey 2-7

233 Additional EM and MAG Surveys 2-8

234 Seismic Refraction Survey 2-8

24 Groundwater Sampling Using Temporary Well Points 2-9

25 Soil Gas Survey 2-12

26 Soil Borings at Disposal Areas 2-15

261 Phase 1A Soil Borings 2-15

262 Phase IB Soil Borings 2-16 27 Installation of Monitoring Wells and Background Soils Sampling 2-17

271 Phase 1A Monitoring Well Placement-Rationale 2-19

272 Phase IB Monitoring Well Placement-Rationale 2-21

273 General Monitoring Well Installation Techniques 2-22

274 Stream Piezometers and Gauges 2-24

5797wpdocsgalluprifinaltextmarterrifhl061297 i QST Environmental

Gallups Quarry Superjund Project - Remedial Investigation

Table of Contents (continued)

275 Groundwater Piezometers 2-25

28 Aquifer Parameter Testing 2-25

281 Grain Size Analysis 2-25

282 Slug Tests 2-26

283 Constant Flow Tests 2-26

29 Groundwater Sampling 2-26

291 Monitoring Wells 2-27

292 Residential Wells 2-29

210 Surface Water and Sediment Sampling 2-29

211 Wetland Soil Sampling 2-31

212 Evaluation of Existing Monitoring Wells 2-31

213 Ecological Assessment 2-32

2131 Wetland Delineation 2-32 2132 Plant and Wildlife Survey 2-33

214 Test Pit Explorations 2-33

30 Physical Characteristics of the Study Area 3-1

31 General Characteristics 3-1

311 Regional Physiography 3-1

312 Study Area Physiography 3-1

313 Surface Water Features 3-2

314 Climate 3-3

32 Geology 3-3

321 Regional Surficial Geology 3-3

322 Local Surficial Geology 3-4

323 Regional Bedrock Geology 3-7

324 Local Bedrock Geology 3-8

33 Hydrogeology 3-9

331 Hydraulic Conductivity 3-9

332 Groundwater Flow 3-10

34 Ecology 3-17

341 Wetland Delineation 3-17

342 Plant and Animal Survey 3-19

40 Nature and Extent of Contamination 4-1

41 Contaminant Source Investigation 4-2

5797wpdocsggtlluprifinaltextmasteiTifhl061297 ii QST Environmental

Gallups Quarry Superfitnd Project - Remedial Investigation


411 Visual Site Reconnaissance 4-2

412 Soil Vapor Survey 4-4

413 Geophysical Investigations and Test Pits 4-5

414 Background Soils 4-6

415 Soils From Former Known Disposal Areas 4-7

416 Contaminant Source Investigations Summary 4-15

42 Groundwater Quality 4-17

421 Temporary Well Point Investigation 4-17

422 Groundwater Monitoring Wells 4-18


43 Surface Water Sediment and Wetland Soils 4-27 431 Surface Water 4-27

432 Sediment 4-31

433 Wetland Soils 4-32

44 Air Quality 4-34

441 Baseline Air Quality Survey 4-34

442 Perimeter Air Monitoring 4-34

45 Potential Sensitive Human Receptors 4-35

50 Contaminant Fate and Transport 5-1

51 Theory 5-1

511 Advection by Groundwater Flow 5-1

512 Dispersion 5-3 513 Advection Due to Fluid Density Differences 5-5

514 Biological and Chemical Degradation 5-5

515 Volatilization 5-7

516 Aqueous Solubility 5-7

52 Study Area-Specific Characteristics 5-7

521 Retardation Factors 5-7

522 Chemical Migration Rates 5-9

523 Time-Dependent Concentration Reductions 5-14

5797wpdocBg8lluprifinaltextmlaquo8terrifhl061297 Hi QST Environmental



60 Summary and Conclusions 6-1

61 Conceptual Model of the Study Area 6-1

611 Geology 6-1

612 Hydrogeology 6-2

613 Nature and Extent of Contamination bdquo 6-5

70 References 7-1

5797wpdocsgnlluprifinlaquoltextmasterriftil061297 Jy QST Environmental

Gallups Quarry Superand Project - Remedial Investigation


List of Tables

Table 1-1 Summary of Results of Groundwater Analyses (CTDEP)

Table 1-2 Summary of Results of Groundwater Analyses (MampE 1993)

Table 1-3 Summary of Results of Groundwater Analyses Former Pervel Flock Plant (HRP)

Table 2-1 Microwell Sampling Intervals

Table 2-2 Former Disposal Area Soil Samples Submitted for Laboratory Analyses

Table 2-3 Monitoring Well Survey Data and Screen Intervals

Table 2-4 Geologic Descriptions of Soil Samples Collected for Grain Size Analyses

Table 2-5 Sample Inventory

Table 2-6 Existing Well Summary

Table 3-1 Hydraulic Conductivity Values

Table 3-2 Hydraulic Conductivity Values Estimated from Grain Size Distributions

Table 3-3 Monitoring Well Water Level Elevation Data

Table 3-4 Summary of Vertical Hydraulic Gradients Between Pairs of MWs in Study Area

Table 3-5 Stream Piezometer Water Level Elevation Data

Table 3-6 Plants Identified During the Wetland Delineation

Table 4-1 Summary of Visual Site Reconnaissance

Table 4-2 Background Soil Volatile Organic Compounds Table 4-3 Background Soil MetalsCyanide

Table 4-4 Disposal Areas Soil Volatile Organic Compounds

Table 4-5 Disposal Areas Soil Semivolatile Organic Compounds

Table 4-6 Disposal Areas Soil PesticidesPCB

Table 4-7 Disposal Areas Soil MetalsCyanide

Table 4-8 Microwell Survey Selected Volatile Organics

Table 4-9 Microwell Survey Results of Volatile Organics Laboratory Analyses

Table 4-10 Microwell Survey Results of Inorganic Laboratory Analyses

Table 4-11 Groundwater Volatile Organic Compounds January 1995

Table 4-12 Groundwater Volatile Organic Compounds April 1995

Table 4-13 Groundwater Volatile Organic Compounds July 1995

Table 4-14 Groundwater Volatile Organic Compounds November 1995

5797wpdocggalluprifinraquoltextmalaquoterrifhl061297 QST Environmental



List of Tables (Contd)

Table 4-15 Groundwater Volatile Organic Compounds February 1996

Table 4-16 Groundwater Volatile Organic Compounds May 1996

Table 4-17 Groundwater Volatile Organic Compounds August 1996



Table 4-20 Groundwater Semivolatile Organic Compounds January 1995

Table 4-21 Groundwater Semivolatile Organic Compounds April 1995

Table 4-22 Groundwater Semivolatile Organic Compounds July 1995

Table 4-23 Groundwater Semivolatile Organic Compounds November 1995

Table 4-24 Groundwater Semivolatile Organic Compounds February 1996

Table 4-25 Groundwater Semivolatile Organic Compounds May 1996 Table 4-26 Groundwater Semivolatile Organic Compounds August 1996



Table 4-29 Groundwater PesticidesPCB April July and November 1995 February and August 1996 February 1997

Table 4-30 Groundwater MetalsCyanide January 1995

Table 4-31 Groundwater MetalsCyanide April 1995

Table 4-32 Groundwater MetalsCyanide July 1995

Table 4-33 Groundwater MetalsCyanide November 1995

Table 4-34 Groundwater MetalsCyanide February 1996

Table 4-35 Groundwater MetalsCyanide May 1996

Table 4-36 Groundwater MetalsCyanide August 1996


Table 4-38 Groundwater Metals February 1997

Table 4-39 Residential Wells Volatile Organic Compounds January 1995

Table 4-40 Residential Wells Volatile Organic Compounds July 1995

Table 4-41 Residential Wells Volatile Organic Compounds February 1996

Table 4-42 Residential Wells Volatile Organic Compounds August 1996

Table 4-43 Residential Wells PesticidesPCB January 1995

Table 4-44 Residential Wells PesticidesPCB July 1995

Table 4-45 Residential Wells PesticidesPCB February 1996

Table 4-46 Residential Wells PesticidePCB August 1996

Table 4-47 Residential Wells Metals January 1995

5797wpdocsg lluprifinaltextmastemfiil061297 VI QST Environmental




Table 4^8 Residential Wells Metals July 1995

Table 4-49 Residential Wells MetalsCyanide February 1996

Table 4-50 Residential Wells MetalsCyanide August 1996

Table 4-51 Field Observations of Habitat and Water Quality September 1994

Table 4-52 Surface Water Quality April and November 1995 May and November 1996

Table 4-53 Surface Water Volatile Organic Compounds September 1994

Table 4-54 Surface Water Volatile Organic Compounds April 1995

Table 4-55 Surface Water Volatile Organic Compounds November 1995

Table 4-56 Surface Water Volatile Organic Compounds May 1996


Table 4-58 Surface Water Volatile Organic Compounds September 1994 April 1995 May

1996

Table 4-59 Surface Water Total MetalsCyanide September 1994

Table 4-60 Surface Water Dissolved Metals September 1994

Table 4-61 Surface Water Total Metals April 1995

Table 4-62 Surface Water Dissolved Metals April 1995

Table 4-63 Surface Water Total and Dissolved Metals November 1995

Table 4-64 Surface Water Total and Dissolved Metals May 1996


Table 4-66 SedimentWetland Soils Metals September 1994

Table 4-67 SedimentWetland Soils Volatile Organic Compounds September 1994 Table 4-68 SedimentWetland Soils Semivolatile Organic Compounds September 1994

Table 4-69 SedimentWetland Soils PesticidesPCB September 1994

Table 4-70 Human Receptors Survey Location of Day Care Facilities Within 1-Mile Radius

of Site

Table 5-1 Fate and Transport Parameters for Study Area Volatile Organic Compounds

Table 5-2 Total Organic Carbon Measurements for Soil Samples

Table 5-3 Historical Concentration Data

5797wpdoclaquoglaquolluprifinaltextmasterriftil061297 Vll QST Environmental



List of Figures

Figure E-l Site Location Map

Figure E-2 Site Wide Groundwater Flow

Figure 1-1 Site Location Map

Figure 1-2 Property Boundaries and Adjacent Landowners

Figure 1-3 Surface Water and Groundwater Classification Zones and Locations of Former

Disposal Areas

Figure 1-4 Groundwater Monitoring Wells Installed by Fuss amp ONeill

Figure 1-5 Site Location Map and Nearby Industrial Properties

Figure 3-1 Groundwater Elevations MW101 Series Figure 3-2 Groundwater Elevations MW102 Series

Figure 3-3 Groundwater Elevations MW103 Series

















Figure 3-20 Groundwater Elevations SW3 Series

Figure 3-21 Three-Dimensional Groundwater Flow Map

5797wpdoc8galluprifiruiltextmasterriftil061297 viii QST Environmental



Figure 5-1

Figure 5-2

Figure 5-3

List of Figures (Contd) Groundwater VOC Concentrations vs Time - Downgradient from Former

Primary Disposal Area

Groundwater VOC Concentrations vs Time - Near Former Pervel Facility

Groundwater VOC Concentrations vs Time - Downgradient Portion of VOC

Plume

Figure 5-4 Evaluation of Biodegradation and Rainwater Dilution Rates in VOC Plume

5797wpdocraquogalluprifinaltextmasterrifhl061297 ix QST Environmental



List of Plates

Plate 2-1 Baseline Survey Grid Air Monitoring Seismic Refraction Line Locations

Plate 2-2 Microwell Locations

Plate 2-3 Soil Vapor Probe and Soil Boring Locations

Plate 2-4 Monitoring Wells PiezometersStream Gauge Locations

Plate 2-5 Residential Well Locations

Plate 2-6 Surface WaterSediment and Wetland Soil Sampling Locations

Plate 2-7 Location of Test Pits Performed at Geophysical Anomalies

Plate 3-1 Study Area Topographic Features

Plate 3-2 Geologic Cross-Sections A-A amp C-C Plate 3-3 Geologic Cross-Section D-D

Plate 3-4 Geologic Cross-Section B-B Plate 3-5 Geologic Cross-Sections E-Eamp F-F

Plate 3-6 Bedrock Surface Contour Map

Plate 3-7 Bedrock Fracture Zones as Determined by Seismic and Magnetometer Surveys

Plate 3-8 Lower Overburden Piezometric Surface November 6 1995

Plate 3-9 Shallow Overburden Piezometric Surface November 6 1995

Plate 3-10 Saturated Overburden Thickness November 6 1995

Plate 3-11 Bedrock Piezometric Surface November 6 1995

Plate 3-12 Vertical Ground water Flow Through Plume Center Line

Plate 3-13 Deep vs Shallow Piezometric Head Differences

Plate 3-14 Wetland Delineation Map September 1994

Plate 4-1 Survey Grid amp Features Noted During Site Reconnaissance August-September

1994

Plate 4-2 Former Primary Disposal Area Soil Borings VOC Data and Cross-Sections

Plate 4-3 Former Primary Disposal Area Soil Borings PCB Data and Cross-Sections

Plate 4-4 VOC Detections Field GC and Laboratory Analyses in Microwells

Plate 4-5 Laboratory Results of Metals Analyses in Microwells

Plate 4-6 Groundwater VOC Data January April July and November 1995 Sampling

Events

Plate 4-7 Groundwater VOC Data February May August and November 1996 and

February 1997 Sampling Events

Plate 5-1 Groundwater Travel Times in Overburden Aquifer November 6 1995

5797wpdocsgi lluprifinaltextmasteirifnl061297 X QSTEnvironmental



List of Appendices

Appendix A Weston Geophysical Inc Report

Appendix B Microwell Logs

Appendix C Soil Boring and Rock Coring Logs and Well Construction Forms

Appendix D Groundwater Sampling Forms

Appendix E Test Pit Logs

Appendix F Single-Well Hydraulic Conductivity Test Procedures

Appendix G Grain Size Data

Appendix H Phase 1A Laboratory Reports

Appendix I April 1995 Laboratory Reports

Appendix J July 1995 Laboratory Reports

Appendix K Phase IBNovember 1995 Laboratory Reports

Appendix L February 1996 Laboratory Reports

Appendix M May 1996 Laboratory Reports

Appendix N August 1996 Laboratory Reports

Appendix O November 1996 Laboratory Reports

Appendix P February 1997 Laboratory Reports

Appendix Q Data Validation Reports

Appendix R pH TOC Moisture Results Soil Samples

Appendix S Environmental Metals Statistics

Appendix T Air Monitoring Results

Appendix U Model of Groundwater Near Mill Brook Appendix V Methodology for Piezometric Head Contouring and Groundwater Pathline

Generation

5797wpdocsgalluprifinlaquoltextmagterri fhl061297 XI QST Environmental


10 Introduction

11 Purpose of the Report This document presents the Remedial Investigation Report (RI) which was completed for the

Gallops Quarry Superfund Site (Site) pursuant to the requirements of US Environmental

Protection Agency (EPA) Administrative Order by Consent Docket Number 1-93-1080 (Order)

issued September 7 1993 The Gallups Quarry property is the site of a former sand and gravel

quarry and is located on Tarbox Road in the town of Plainfield Windham County Connecticut

(see Figure 1-1) According to the Town of Plainfield Tax Assessors office the property (Map

10 Block 30 Lot 32) is an irregularly shaped parcel comprised of approximately 29 acres

Investigation of the quarry was initiated in 1978 when unlicensed waste disposal operations were

discovered at the property Emergency clean-up operations were conducted by the Connecticut

Department of Environmental Protection (CTDEP) in April 1978 (Metcalf amp Eddy 1993)

Following the initial clean-up effort a study was conducted to characterize the nature and extent

of residual contamination at the Site (Fuss amp ONeill 1979) A series of surface and subsurface

sampling events conducted by the CTDEP the Connecticut Department of Health and the US

Environmental Protection Agency (EPA) between the years of 1978 and 1988 prompted EPA to

propose on June 21 1988 that the Site be listed on the National Priorities List (NPL) The Site

was finally listed on the NPL on October 4 1989 During 1992 and 1993 EPA conducted a

limited investigation through the Superfund Technical Assessment amp Response Team (START)

initiative in an effort to expedite the completion of the Remedial InvestigationFeasibility Study

(RIFS) The requirements of the Order as well as data included in the START report (Metcalf

amp Eddy 1993) provided the framework for this investigation

This Report is the sixteenth major deliverable under the Order The first major deliverable the

Remedial InvestigationFeasibility Study Work Plan - Phase 1A was finalized and submitted to

EPA on August 29 1995 QST Environmental (formerly Environmental Science amp Engineering

Inc (ESE)) finalized the Work Plan and has prepared all of the other deliverables The Phase 1A

field investigation was completed in January 1995 The second major deliverable the Phase 1A

Data Report dated March 24 1995 was submitted to EPA following completion of the Phase 1A

field investigation The findings of the Phase 1A investigation were described in the Initial Site

Characterization Report (ISCR) which was finalized and submitted to EPA on March 1 1996 A

Work Plan for the Phase IB field investigation was also finalized and submitted on October 11

1995

In addition to the actual Phase 1A field investigation the Phase 1A Work Plan also described the

Long Term Monitoring Program which was initiated upon completion of the Phase 1A field

5797wpdocraquogalluprifinaltextmlaquoiterrifhl061297 1-1 QST Environmental


investigation The Long Term Monitoring Program includes the quarterly collection and analysis

of groundwatei and semi-annual collection and analysis of surface water and nearby residential

well samples

The Phase IB field investigation commenced on October 12 1995 Following the completion of

drilling activities the Phase IB groundwater sampling task and the fourth quarter 1995 Long

Term Monitoring sampling event were performed simultaneously in November 1995 Seven

Data Reports have been submitted to the EPA for the following Long-Term Monitoring Program

sampling events the second and third quarters of 1995 all four quarters of 1996 and the first

quarter of 1997 (ESE 1996a 1996b 1996c 1997a 1997b) The draft RI Report was submitted

to EPA on March 15 1996 (and revised and resubmitted October 22 1996) and included the

results of the fourth quarter of 1995 sampling event On March 29 1996 the following two

deliverables were submitted to EPA Development and Initial Screening of Alternatives Report

and Detailed Analysis Work Plan The draft Feasibility Study was submitted to EPA on January

27 1997 This RI Report describes the methods and findings of both the Phase 1A and IB field

studies and includes data collected during the April July and November 1995 February May

August and November 1996 and February 1997 Long-Term Monitoring sampling events

12 Report Organization The RI is presented in seven main sections following the Executive Summary The remainder of

Section 1 presents Site background information Section 2 presents the various field methods and

procedures used during the field investigations including descriptions of any changes or

deviations from the Work Plan Section 3 describes the physical characteristics of the Study

Area and Section 4 presents the findings of studies designed to determine the nature and extent of

contamination within the Study Area Section 5 is a discussion of the various fate and transport

mechanisms associated with the contaminants of concern Section 6 summarizes the conceptual

model of conditions within the Study Area Finally a list of references cited in this report is

presented in Section 7

Volume 1 of this Report presents the text and figures of the RI Volume 2 contains all Tables

referenced in the report Volume 3 contains all Plates referenced in the Report Volume 4 and

all subsequent volumes contain the Appendices referenced in the Report

5797wpdocggaIluprifinaltextmasterrifhl061297 1-2 QST Environmental


13 Site Background 131 Area Description Demography and Land Use

For the purposes of this report the Site is considered to be the actual property owned by the

late Stanton Gallup from 1964 until his death in 1994 The Study Area includes the Site as

well as surrounding properties from which data were collected during the RI

The Site is located on the north side of Tarbox Road in the Town of Plainfield Windham County

Connecticut (see Figure 1-1) The Site is situated approximately 2000 feet west of interchange

87 on Interstate 395 and approximately one-mile southwest of Plainfield Center As shown on

Figure 1-2 the Site is irregularly shaped and is approximately 2200 feet long (north to south)

and 300 to 1100 feet wide (east to west) A number of previous references have described the

Site as ranging in size from 20 to 22 acres however the Town of Plainfield Tax Maps and areal

calculations performed by ESE indicate that the size of the Site is approximately 29 acres In

addition to the Site the Study Area includes additional areas located to the north and northwest of

the Site (as shown on Figure 1-1) and a number of discrete smaller areas located to the east and

south of the Site used for collecting upgradient surface watersediment samples

The Site is currently vacant and much of it is heavily vegetated Numerous overgrown mounds

and excavations are scattered across the Site and are presumed to be features remnant of the

former sand and gravel quarry operations Other than concrete foundations remnant of former

Site operations no structures presently exist on the property Surface features observed on the

Site during the Phase 1A visual reconnaissance survey are described in more detail in Section

411

As shown on Figure 1-2 the Site is bounded to the east by Route 12 (Norwich Road) single-family residences and a plumbing supply company An active railroad right-of-way (presently

operated by the Providence and Worcester Railroad) bounds the Site to the west Wooded areas

and wetlands associated with Mill Brook bound the Site to the north and Tarbox Road and several

single family residences bound the Site to the south

Surface water bodies located within or near the Study Area include Mill Brook Fry Brook and

Packers Pond As shown on Figure 1-3 Mill Brook flows from east to west along the northern

edge of the Study Area until its confluence with Fry Brook Mill Brook turns toward the south

at this confluence and continues flowing in a south-southwesterly direction (as Mill Brook) and

eventually drains into Packers Pond [Note Packers Pond is not shown on Figure 1-3 due to the

larger scale of this figure however the relative location of Packers Pond approximately 1 mile

west of the Site can be seen on Figure 1-1]

5797wpdocBgalluprifinaltextmasteiTifhl061297 1-3 QST Environmental


Based on the CTDEP Water Quality Classification Map of Thames Southeast Coast and

Pawcatuck River Basins Sheet 2 of 2 (1986) surface water located within the section of Mill

Brook between Route 12 and the confluence with Fry Brook (shown on Figure 1-3) is classified

as BA The BA classification indicates that the surface water body may not be meeting the

Class A water quality criteria for one or more designated uses which include potential drinking

water supply fish and wildlife habitat recreational use and agricultural and industrial supply

although the goal is to ultimately restore the water body to Class A standards Surface water

within Fry Brook and the lower section of Mill Brook (located down stream of the confluence of

the two brooks) is classified as Be The Be classification indicates that the water meets Class B

criteria and is suitable for cold water fisheries The designated uses for Class B surface water

include most of those described for Class A however Class B waters are NOT designated as a

potential drinking water supply Surface water located within Packers Pond (not shown on Figure

1-3) is designated as CBc The CBc designation indicates that Packers Pond is not meeting the

Class B water quality criteria for one or more designated uses or is a Class C water body which

is basically a downgraded version of Class B However the CTDEP goal for surface water

designated as CBc is to restore it to Class B conditions

As shown on Figure 1-3 groundwater located within the northern portion of the Study Area

between Route 12 and the MillFry Brook confluence is classified as GBGA which indicates that

the groundwater may not be suitable for direct human consumption without the need for treatment

due to waste discharges spills or leaks of chemicals or land use impacts The CTDEP goal for

groundwater classified as GBGA is to prevent further degradation by preventing any additional

discharges which would cause irreversible contamination Groundwater at all other locations

within the Study Area is classified as GA which is presumed suitable for direct human

consumption without need for treatment In addition one of the goals of the CTDEP for

groundwater classified as GBGA is to restore it to GA standards

It should be noted that the surface water classifications described above are based on existing

CTDEP maps which were published prior to the preparation of this report During the course of

this investigation the CTDEP proposed amendments which were intended to clarify the language

of the States Water Quality Standards and simplify the Departments system for considering

requested modifications Based on conversations with a representative of the CTDEP (Personal

Communication Bobowitz 1996) the single letter (eg Class A) and dual letter (and associated

goal) classification (eg BA) system will be maintained Areas presently designated by dual

classifications will only be modified once the desired goal for that water body or aquifer has been

attained According to the CTDEP the only significant change will be the eventual elimination of

the use of lower case suffixes (eg Be) which are currently used to indicate very specific

restrictions or uses for certain water bodies (ie B rather than Be)

5797wpdocsgalluprifinaltextmasterrifhl061297 1-4 QST Environmental


Within the Study Area directly west of the Site (across the railroad tracks) are open cropland

(presently a cornfield) wooded areas and a residential property (parcel 24 shown on Figure 1shy

2) The property boundaries and land owners for the Site and other nearby parcels are also

shown on Figure 1-2 Immediately north of the Site are approximately 85 acres of wooded

undeveloped land through which flows Mill Brook An overhead power line easement (not shown

on Figure 1-2) runs adjacent to the northernmost Site boundary On the north side of Mill Brook

is an industrial park which contains an Intermark Fabric Corporation facility (formerly the Pervel

Industries flock plant) and a Safety Kleen Corporation accumulation facility Northeast of Mill

Brook are woodlands and Saint Johns Cemetery Further north of the industrial park are several

vacant mill buildings which were occupied until the late 1980s by various manufacturers including

Pervel Industries and the InterRoyal Corporation The Plainfield sewage treatment plant which

discharges to Mill Brook and its major tributary (Fry Brook) is located approximately 1800 feet

northwest of the property

The Town of Plainfield with a land area of 427 square miles has a population of approximately

14200 Plainfields principal industries include varied manufacturing and distribution centers as

well as tourism based businesses In addition the rural areas of Plainfield are occupied by many

small dairy and produce farms

^ 132 Operational History

Information regarding the operational history of Gallups Quarry was obtained from published

reports for previous Site studies including Site Analysis Gallups Quarry Plainfield CT

(Bionetics Corporation 1990) and Final Data Summary Report START Initiative (Metcalf amp

Eddy 1993) as well as information from various sources collected during the preparation of the

Gallups Quarry Remedial InvestigationFeasibility Study Work Plan (ESE 1994) Little detailed information concerning the early operational history of the Site exists

A review of an aerial photograph of the Site taken in 1951 depicts the Site as an undeveloped

parcel although some quarry activities in the southern portion of the property appear to be

underway (ESE 1994) Records at the town of Plainfield Assessors office indicate that in 1951

the Site was owned by a Mr Johnson who was operating a sand and gravel quarry In 1964 the

Site was purchased by C Stanton Gallup (Metcalf amp Eddy 1993) Although detailed usage of

the Site from 1964 through 1977 is poorly documented records indicate that the Site was used as

a source of aggregate and was occupied by the Connecticut Department of Transportation

(CTDOT) which operated an asphalt batching plant (ESE 1994) The exact date of CTDOT

presence at the Site is unclear although it is believed to coincide with the construction of Route

52 (now known as Interstate 395) Evidence of the former asphalt batching plant operations are

5797wpdocsgalluprifinalteirtinalaquoterrifhl061297 1-5 QSTEnvironmental


still present at the Site Mounds of asphalt paving material and areas covered with hardened

liquid asphalt ere observed at a number of locations throughout the Site


Police initiated an investigation of the Site in early January 1978 During a Site visit on January

13 1978 representatives of the CTDEP reportedly observed partially buried drums containing

suspected hazardous materials and ordered that all Site operations be stopped The CTDEP

investigation concluded that the Site was used from the summer of 1977 until December 1977 for

unlicensed waste disposal

As described in the Order evidence collected by CTDEP indicates that Chemical Waste Removal

Inc (CWR) of Bridgeport Connecticut transported drummed and bulk liquid waste material to the

Site and was the sole known transporter of waste to the Site These wastes reportedly included a

variety of industrial wastes which were transported to and disposed of at the Site It was reported

that Mr Gallup jointly operated the quarry with Mr Dick Trayner of Dick Trayner and Sons

Trucking Company at the time of the illegal waste disposal activities

According to CTDEP and State Police records the drums and liquid wastes were reportedly

disposed of at three distinct locations on the Site These areas were subsequently labeled the

Primary Disposal Area the Secondary Disposal Area and the Seepage Bed The Primary and

Secondary Disposal Areas were reportedly located in the northern portion of the Site while the

Seepage Bed was reportedly located in the central portion of the Site The reported locations of

these former disposal areas are shown on Figure 1-3

According to a report issued by Fuss amp ONeill (FampO 1979) the Primary Disposal Area

consisted of an area approximately 04 acres in size The Secondary Disposal Area was described

by the FampO report as a linear trench which encompassed an approximate area of 007 acres

located adjacent to the railroad tracks and just west of the Primary Disposal Area The Seepage

Bed was located in the central portion of the Site and according to the FampO report was

approximately 40 feet by 50 feet in size and consisted of an excavation into which an inverted

truck body filled and covered with crushed stone was placed A metal pipe which extended

from the dump body to the ground surface was reportedly used for direct discharge of liquid

wastes According to the FampO report the liquid wastes reportedly disposed of in the Seepage

Bed consisted of low pH liquids which were believed to be by-products associated with metal

finishing operations

Initial cleanup efforts were performed by Chem-Trol Inc during the summer of 1978 under the

direction of the CTDEP and the Connecticut State Police A Connecticut State Police Possessed

5797wpdocsglaquolluprifinaltextmasterrifhl061297 1-6 QSTEnvironmental


Property Report (PPR) lists the following materials as removed from the Site 1584 drums (some

of which were crushed andor decomposed) 5000 gallons of free liquid and 2277 cubic yards

of contaminated earth The PPR also lists 127715 tons of moderately contaminated soil which

was removed from the Site Additional remedial measures included the neutralization of residual

contamination at the Seepage Bed by placing 20 tons of lime at that location

Although no information concerning the actual number of drums or quantity of waste transported

to the Site by CWR is available it was believed that all of the drums had been recovered upon

completion of the cleanup operations Mine detectors were utilized to search for additional buried

drums however no indications of additional buried drums were discovered

Since the 1978 cleanup operations the Site has been vacant Public vehicular access to the Site

has been limited by the placement of boulders and mounded soil at access locations around the

Site During this time evidence of off-road vehicle tire tracks and small quantities of debris

(beverage cans bottles spent shotgun shell casings and empty gasoline cans) indicate that the

Site has been utilized by trespassers for recreational purposes However it appears that Site

usage has decreased since August 1994 when fencing and additional boulders were placed at

potential access locations and the perimeter of the property was posted with warning signs

133 Summary of Previous Investigations

Following the CTDEP removal activities a number of environmental investigations and sampling

events were conducted at the Gallups Quarry Site This section summarizes environmental

studies conducted at the Site prior to the RIFS as compiled performed and reported by Metcalf

amp Eddy (1993) as part of the EPAs Region I START Initiative or as reported by the original

investigators)

1331 Evaluation of a Chemical Waste Disposal Area Tarbox Road Site Plainfield Connecticut Fuss amp ONeill 1979

Between June 6 and October 30 1978 Fuss amp ONeill Inc performed a hydrogeological

investigation within the Study Area in conjunction with the cleanup and remedial operations

directed by the CTDEP and Connecticut State Police The findings of this investigation were

presented in a report issued to the CTDEP dated January 29 1979 The tasks completed during

this investigation included the following

bull The installation of 22 test borings which were completed as groundwater

monitoring wells (SW series) including three shallow-bedrock wells near the

Former Seepage Bed (SW-10 SW-11 SW-12) The locations of these wells are

shown in Figure 1-4

5797wpdocsgalluprifinaltextmlaquo8terrifhl061297 1-7 QST Environmental


bull Excavation of 19 test pits (using a backhoe) 13 of which were completed as

shallow groundwater monitoring wells

bull The establishment of 12 surface water gauging stations along Mill Brook and Fry

Brook

bull The collection of surface water and groundwater water for laboratory analysis

FampO collected groundwater samples from the monitoring wells in July October and December

1978 Several nearby domestic wells were also sampled in July and October 1978 Groundwater

samples were analyzed for metals volatile organic compounds (VOC) and the following general

chemical parameters chemical oxygen demand (COD) total dissolved solids (TDS) total

Kjeldahl nitrogen (TKN) chloride total organic carbon (TOC) total carbon total cyanide

specific conductance and pH

FampO also collected surface water samples from seven of the stream gauging stations in

September October and November 1978 In general the surface water samples were analyzed

for the same chemical parameters described above

The chemical testing results indicated groundwater in the vicinity and downgradient of the Former

Disposal Areas had been impacted by several organic and inorganic constituents VOC detected

included ethanol methanol isopropanol ethyl acetate acetone toluene benzene trichloroethene

(TCE) 111- trichloroethane (TCA) tetrachloroethene (PCE) methyl isobutyl ketone (MIBK)

methyl ethyl ketone (MEK) and methylene chloride Various metals including aluminum

chromium copper magnesium nickel zinc iron and silver were reported at widely variable

concentrations in some groundwater samples According to the START Report the domestic

wells did not appear to be significantly impacted

FampO concluded that a well-defined groundwater contaminant plume extended from the former

disposal areas towards Mill Brook northwest of the Site and that the flow direction of the plume

was controlled by the local water table gradient The plume was characterized by the presence of

organic compounds which included acetate benzene ethanol isopropanol MEK MIBK

toluene TCA and xylene The plume also contained widely variable concentrations of various

metals including copper nickel boron aluminum magnesium manganese iron silver

cadmium and lead

The START Report indicated that since little or no information is available regarding FampOs field

methods (eg field notes chain-of-custody collection of field QC samples) or analytical

5797wpdoc8galluprifinaltextmastemfnl061297 1-8 QST Environmental


methods (eg detection limits turbidity filtering sample preservation analysis of lab QC

samples) comparison of the test results to current regulatory criteria (eg Maximum Contaminant

Levels [MCL]) was not appropriate for any definitive purpose

1332 CTDEP Periodic Monitoring 1979 to 1983

As described in the START Report the CTDEP performed periodic monitoring of groundwater

(including domestic wells) surface water and sediment in the Study Area from 1979 until 1983

The periodic monitoring was not systematic in terms of the wells or locations that were sampled

or the parameters tested for The results of the CTDEP monitoring are in the form of laboratory

results compiled and presented in the START report A summary table of results for the CTDEP

groundwater monitoring activities as presented in the START report is included in this report as

Table 1-1

The dates of groundwater sample collection and analysis for the CTDEPs monitoring program

are as follows

bull October 1979

bull January 1980

bull November 1980

bull April 1981

bull October 1981

bull April 1982

Sample analytical parameters varied from event to event but typically included pH COD

specific conductivity hydrocarbons chlorides and selected metals (cadmium chromium copper iron nickel and zinc)

The CTDEP also collected surface water and sediment samples on the following dates

bull January 1980 (surface water)

bull October 1981 (surface water and sediment)

bull April 1982 (surface water)

bull December 1983 (surface water)

It was noted in the START Report that no information was available regarding the CTDEP sampling methods or analytical procedures and that this limited the usefulness of the data except

for comparative purposes Nonetheless the START Report concluded that the available analytical

data collected by CTDEP during the period from 1972 to 1982 indicated that the Site and areas to

5797wpdoc8falluprifinaltextmasterrifnl061297 1-9 QST Environmental


the north-northwest were impacted by the past disposal of VOC metals and acid wastes This

conclusion wa5 based on the fact that up until the last recorded groundwater sampling event

performed by CTDEP (1982) four monitoring wells (SW7D SW13 SW17S and SW17D)

exhibited detectable concentrations of contaminants characteristic of the types of wastes which

were reportedly disposed of on the Site The contaminants detected in these wells included

various common industrial organic solvents (both chlorinated hydrocarbons and ketones) as well

as several petroleum aromatic hydrocarbons Chlorinated hydrocarbon concentrations for these

wells ranged from 10000 to 80000 parts per billion (ppb) for 111-Trichloroethane (TCA) 30

to 1000 ppb for Tetrachloroethane (PCE) and 1000 to 14000 ppb for Trichloroethene (TCE)

Ketones detected included Acetone (5000 to 22000 ppb) methyl ethyl ketone (MEK) ranged

from 12000 to 150000 ppb and methyl iso butyl ketone (MIBK) ranged from 60 to 7000 ppb)

The main aromatics detected included toluene (up to 17000 ppb) and xylene (up to 3000 ppb)

1333 CTDEP BioDiversity Study 1985

The CTDEP conducted a field survey on November 4 1985 to evaluate potential impacts from

migration of groundwater from the Site to the Mill Brook wetland The study was conducted in

an area where leachate was observed to be breaking out from the wetlands into Mill Brook

The precise location is unclear however the START Report indicates that the impact zone was

subjectively estimated to be approximately 200 feet west of the railroad bridge The leachate

was described as an area showing evidence of organic enrichment and iron hydroxide precipitation

which extended a distance of approximately 100 feet downstream

The study reported a background species Diversity Index value of 257 compared to a value of

236 for the area of study The minor difference in diversity represented by this measure was

primarily considered to be a result of low flow conditions as much higher diversity indices

indicative of excellent water quality were observed during a previous bioassessment in that

area

As part of the CTDEP study four surface water samples were collected (one control and three

downstream) from Mill Brook on 8 November 1985 for acute aquatic toxicity bioassays using

water fleas (Daphniapulex) The results of this testing are summarized in a CTDEP

interdepartmental memorandum (dated November 18 1985) that is included with the results of the

biodiversity study The assay employed three replicates per sample and 10 individual organisms

per replicate The endpoint of the assay was percent survival after 48 hour exposure to the water

All samples yielded average survival rates of greater than 83 Based on the results of the tests

the CTDEP concluded that no acute toxicity was demonstrated

5797wpdocsgalluprifinaltextmasterrifnl061297 1-10 QST Environmental


The BioDiversity study report indicated that well MW17S was sampled and that a strong

solventacid odor was noted Further information on sampling and analyses of this well by

CTDEP in 1985 was not included in the report

1334 Hazard Ranking System (HRS) Study - NUSFIT 1986 to 19874

On September 15 1987 the Superfund Division of NUS Corporation completed the Final HRS

Documentation Package for Gallups Quarry The package contains information on the cleanup

and subsequent environmental evaluations including State Police documents and logs regarding

the investigation into the unlicensed disposal activities CTDEP and State Police documents

concerning cleanup activities affidavits taken from individuals involved in the disposal activities

and miscellaneous correspondence related to the criminal investigation and cleanup activities

The HRS package includes the EPAs Preliminary Assessment for Gallups Quarry which was

completed by NUS in July 1986 During the Preliminary Assessment NUS sampled two of the

existing monitoring wells (SW17D and SW18) and three surface watersediment locations The

surface and groundwater samples were screened in-house for benzene TCE toluene PCE

chlorobenzene ethyl benzene and xylenes None of these compounds were detected in MW18 or

the surface water samples All of the compounds (except chlorobenzene) were detected in

MW17S with toluene and xylenes measured at the highest concentrations With the exception of

pH temperature and conductivity no data were available regarding the sediment samples

Based on a file review and limited sampling the Preliminary Assessment concluded as in

previous studies that VOC contamination existed at the Site and that contaminated groundwater

was migrating in a west to northwest direction from the Site NUS recommended that a Site

Investigation be conducted to further evaluate the on-site conditions and potential off-site impacts

1335 Residential Well Sampling 1989

In 1989 Roy F Weston Inc under contract to EPA collected samples from 10 private wells in

the vicinity of the Site The samples were analyzed for VOC semi-volatile compounds (SVOC)

and metals Very low levels of some VOC (chloromethane TCA and carbon tetrachloride)

SVOC (phthalates) and metals (barium and copper) were detected in several wells but at

concentrations well below their respective EPA MCL In a memo dated May 25 1989 (included

as Appendix G of the START Report) EPA concluded that the levels detected in this investigation

did not represent a public health threat

5797wpdocsgalluprifinaltextmraquosterrifhl061297 1-11 QSTEnvironmental


1336 Site Analysis - Bionetics Corporation 1990

In November 1990 the Bionetics Corporation under contract to EPA completed an analysis of

historical aerial photographs taken of the Site in 1951 1970 1974 1975 1981 and 1988

Based on analyses of these aerial photographs the report suggested that disposal-related activities may have started at the quarry as early as 1970 However this conclusion was based on the

presence of features such as excavated areas mounded materials possible containers and the presence of access roads all of which are also indicative of typical quarrying operations

1337 Health Assessment - US Department of Health and Human Services (DHHS) 1991

The US Department of Health and Human Services completed a Health Assessment for Gallups Quarry on January 30 1991 to assess potential human health effects from exposure to

contamination at the Site The assessment was based on previous chemical testing data available

for the Site (ie data collected by Fuss amp ONeill Inc in 1978 and by CTDEP in 1979 through

1983)

The report concluded that if present at high enough concentrations VOC and heavy metals

detected at the Site could have potential public health implications The report recommended that

a program of groundwater monitoring be instituted along with on-site soil and surface water sampling and that additional health data for the area be evaluated as it becomes available

1338 Residential Well and Surficial Soil Sampling - Roy F Weston 1993

In 1993 Roy F Weston Inc under contract to EPA sampled 8 residential supply wells in the

vicinity of the Site The samples were analyzed for VOC SVOC and metals In addition

Weston collected seven surficial soil samples (within 3 inches of the ground surface) from areas

of apparent staining in the vicinity of the Former Primary and Secondary Disposal Areas Two

samples were collected in January 1993 and the other five were collected in February 1993 The

soil samples collected in January were submitted to the laboratory for analysis for pH and

cyanide and for metals screening using X-ray fluorescence techniques (XRF) The five samples

collected in February were analyzed for cyanide

The results of the XRF screening analyses indicated that the two samples collected in January

contained levels of copper ranging from 160 to 400 ppm No other metals were detected above

normal background levels Cyanide levels for all seven soil samples were reported in the range

of 87 to 345 ppm

5797wpdocsgalluprifinaltextmasterrifiil061297 1-12 QST Environmental


The well water analytical results indicated that 111-TCA was detected in three of the residential

wells at levels of 05 to 12 ppb well below EPA MCL for 111-TCA of 200 ppb Copper and

iron were detected at levels below the EPA MCL in several of the samples analyzed SVOC were

not detected

1339 Groundwater Monitoring and Well Survey Metcalf amp Eddy 1993

In November 1992 Metcalf amp Eddy performed a well condition survey of the remaining existing

monitoring wells at the Site as part of a groundwater monitoring well investigation conducted for

the EPA Thirteen of the original twenty-two monitoring wells installed by Fuss amp ONeill Inc

were located fewer than half of which were determined to be in a condition capable of producing

viable samples In February 1993 Metcalf amp Eddy collected samples from ten of the wells

installed by Fuss amp ONeill Inc and from a USGS well installed in 1992 The samples were

analyzed for VOC SVOC metals and cyanide

Groundwater analytical results were consistent with earlier studies but confirmed that VOC levels

were significantly decreasing with time Low levels of VOC were detected at monitoring wells

SW3S and SW3D located downgradient of the Former Primary Disposal Area and at SW13

located downgradient of the Former Secondary Disposal Area The highest levels of VOC were

detected in wells SW17S (15000 ppb of xylene 1700 ppb of toluene 460 ppb of TCA 34 ppb

of TCE 22 ppb of PCE) and SW17D (1500 ppb of 12-DCE 720 ppb of TCA 16 ppb of TCE

and 27 ppb of PCE) A summary of the results of the 1993 Metcalf amp Eddy monitoring are

presented in Table 1-2 In general the concentrations detected in these wells for this sampling

event were substantially lower than concentrations recorded during the previous groundwater

sampling in 1982

13310 Geohydrology of the Gallups Quarry Area Plainfield Connecticut USGS 1993

In 1993 the United States Geological Survey (USGS) issued a draft report on Geohydrology of

the Gallups Quarry Area Plainfield Connecticut (finalized in 1995) The work was performed as

part of the EPAs START program and was designed to assist in the RIFS scoping process

The USGS study interpreted the subsurface geologic conditions at the Site to provide guidance for

subsequent investigations Field investigations for the study included ground penetrating radar

(GPR) and electromagnetic (EM-34) geophysical surveys the drilling of three test borings the

installation of a monitoring well in one of the borings (shown on Figure 1-4) and the

measurement of flow rate and specific conductance in Mill Brook

5797wpdocraquosalluprifiiultextmasterrifiil061297 1-13 QST Environmental


The USGS investigation provided data on overburden soil units the depth to bedrock and

bedrock structure Existing subsurface information derived from previous test boring logs and the

data collected from the three test borings drilled by the USGS were used in conjunction with GPR

data and the results of the EM-34 terrain conductivity survey to develop geological cross-sections

across the Site In addition the GPR survey indicated the possible presence of a west-northwest

trending fault zone beneath the property located south of the Former Seepage Bed The location

of this suspected fault zone as estimated by the USGS is consistent with the approximate location

inferred by previous regional geological studies (Dixon 1965 and Boynton and Smith 1965)

An electromagnetic survey performed downgradient (northwest) of the Former Secondary and

Primary Disposal Areas indicated a northwesterly-trending pattern of increased terrain

conductivity levels as compared with levels at other areas of the Site The USGS interpreted the

increased levels as possibly indicative of either the presence of a groundwater plume containing

residual metal contamination or a natural change in subsurface strata Surface water

measurements collected in Mill Brook indicated that specific conductance increased slightly

downstream of the railroad bridge however the observed differences were so small that the

USGS did not consider them to be indicative of changes in water quality caused by the presence

of dissolved contaminants

13311 Habitat Characterization for Gallups Quarry Superfund Site US Fish and Wildlife Service March 1995

In June of 1993 the US Fish and Wildlife Service conducted a field survey for the purposes of

characterizing the habitat of the Site and surrounding wetland and stream ecosystems The study

was qualitative in nature conducted on foot by trained biologists with the objective of correlating

observations on habitat (primarily vegetation) with known reference material such as topography

maps and aerial photographs The study also included direct and indirect (eg animal tracks)

observations to assess the presence (or absence) of wildlife

The report provides a description of methods and general Site characteristics as well as a more

detailed discussion of wildlife habitat for both the Site and the Mill Brook wetland ecosystem

The study is partial in that it accents what types of animals would be anticipated to be present for

each habitat type even though most of these animals were not directly observed

The report concludes with a description of 29 different types of cover that can be cross-

referenced to areas delineated on a Site map (not to scale) Several Tables are also presented

which inventory birds mammals reptiles amphibians trees shrubs and herbaceous vegetation

that were either observed or would be expected to inhabit the Site

5797wpdocsgalluprifinaItextmasterriftil061297 1-14 QST Environmental


13312 Adjacent Properties Incident Reports and File Review 1995

To supplement data obtained during the Phase 1A field program a CTDEP file search was

performed to obtain information pertinent to groundwater contamination for industrial properties

neighboring the Site The preliminary findings of this review were submitted in a letter from

ESE to EPA on March 28 1995

A number of incident reports were on file regarding two nearby companies Pervel Industries

Inc and InterRoyal Corporation which have the potential to impact conditions within the Study

Area Figure 1-5 shows the locations of these facilities relative to the Site The significant

findings of the file searches are presented below

Pervel Industries

Pervel Industries Inc manufactured plastic film and laminated textile products (eg flocked

velvet) Pervel reportedly occupied two separate facilities north of the Site The main facility

located approximately 2500 feet north of the Site is believed to have been occupied by Pervel

from the 1940s or 1950s to at least the late 1980s This facility abutted the southern side of the

InterRoyal facility described below A second Pervel facility known as the flock plant (presently

operated by Intermark Fabric Corporation) was located approximately 1000 feet north of the

Site just north of Mill Brook The dates of Pervels occupation at the flock plant cannot be

clearly ascertained from the information available in the files however the review of historic

aerial photographs indicate that the facility has existed since the early 1970s

In 1988 at the request of EPA and CTDEP the NUS Corporation performed a Preliminary

Assessment (PA) at the main facility In an effort to determine eligibility for the National

Priorities List (NPL) NUS reviewed the activities associated with the 1984 closure of a sludge

and waste water lagoon located at the facility Based on their review of the available data NUS

recommended that a Screening Site Inspection (SSI) be performed

The NUS PA report also described a 1985 spill of 600 gallons of 111-TCA and a 1987 spill of

300 gallons of toluene at the northernmost facility According to the PA report contaminated soil

and sediment associated with the 1985 spill was excavated and stored in an impoundment at the

flock plant located just north of the Gallups Site The report indicates the presence of

contaminants in the area where the contaminated soil and sediment were stored suggesting that

the impoundment leaked andor there are other (undocumented) environmental concerns at the

flock plant

5797wpdocraquogalluprifinaltextmlaquosterrifhl061297 1-15 QST Environmental


The results of recent (late 1980s through the early 1990s) quarterly groundwater monitoring

efforts conducted at the former Pervel flock plant (HRP 1993) indicate the presence of a number

of VOC including 111-TCA TCE PCE and 12-DCE well above their respective MCL The

results of these sampling events as summarized in Table 1-3 (from HRP 1993) indicate that

there has been a general decrease in the concentrations of contaminants seen in these wells over

time The highest recorded concentrations for these constituents are as follows 111-TCA (518

ppb) PCE (466 ppb) TCE (63 ppb) and 12-DCE (906 ppb) According to the HRP report

groundwater flow in the vicinity of the former Pervel flock plant is generally from east to west

(towards the northern portion of the Study Area) However these interpretations were based on a

limited number of data points confined to the Pervel flock plant property

InterRoyal Corporation

The InterRoyal Corporation is located adjacent to and just north of the main Pervel facility

described above The CTDEP files include a memorandum from the NUS Corporation to EPA

dated August 18 1989 which references a 1984 Preliminary Assessment performed by CTDEP

which recommended that a low priority Site Inspection be performed The NUS memo presents a

chronology of Site activities up to 1989 which includes CTDEPs 1987 finding that the company

was in violation of several State Hazardous Waste Management regulations and CTDEPs

subsequent revocation of InterRoyals NPDES permit Based on a CTDEP 1988 Site inspection

NUS recommended to EPA that a high priority Screening Site Inspection be conducted

In 1988 InterRoyal contracted an environmental consultant to prepare an environmental

assessment (EA) for the proposed sale of the property The EA report (ERT 1988) concluded

that substantive on-site contamination of groundwater surface water and soils existed The

principal contaminants were identified as VOC (including TCE trans-l2-DCE PCE vinyl

chloride toluene and xylenes) and priority pollutant metals Groundwater flow direction was

described in the EA report as principally towards the south and southwest

5797wpdoc8galluprifinaltextmasterrifhl061297 1-16 QZT Environmental


20 Field Investigations

This Section describes the field methods and procedures used to accomplish the various field

investigation tasks performed during Phase 1A and Phase IB Also included are descriptions of

any deviations from the approved Work Plan As noted in the appropriate subsections any

deviations from the Work Plan were approved by EPA (or EPAs oversight contractor) prior to

implementation Discussions of the findings results and significance of these investigations are

presented in Sections 3 and 4 of this Report

21 Site Survey 211 Initial Site Survey At the start of the Phase 1A field investigation an initial Site survey was performed to confirm

and update the location and elevation of features included in the base map provided by EPA (EPA

drawing number 707600 dated October 14 1993) The initial Site survey also served as Site

control by establishing a 250-foot grid across the entire Site which was identified by the

installation of labelled stakes at the intersection of each 250-foot grid line Horizontal control for

the 250-foot grid (and all subsequently surveyed features) coincides with the Connecticut State

Plane Coordinate System North American Datum of 1927 Vertical control coincides with the

National Geodetic Vertical Datum (NGVD) of 1929 and was established using nearby USGS benchmarks The 250-foot grid (shown on Plate 2-1) provided known reference locations from

which field personnel could measure the locations of Site features

In addition to the 250-foot control grid the initial survey also established a series of parallel lines

(trend lines) across the Site for use during subsequent visual reconnaissance and geophysical

surveys The trend lines (also shown on Plate 2-1) are roughly parallel to the Providence amp Worcester railroad which abuts the western edge of the property The first trend line (Line A)

was located approximately 50 feet east of the railroad right-of-way with subsequent lines (Line

B through Line HH) spaced at 25-foot intervals Each of the trend lines were staked at 250shy

foot intervals using labelled stakes

212 As-Installed Survey

Following the initial Site survey additional surveying events were performed as needed

throughout the duration of the Phase 1A and Phase IB field investigation programs to locate

various sampling locations and other pertinent investigation features These subsequent surveys

were initiated shortly after the completion of each investigation task Besides the various

surveyors control features such as temporary benchmarks and turning points the features

surveyed included wetland delineation flags surface watersediment and wetland soil sampling

5797wpdocsglaquolluprifinlaquoltextrnasterrifhl061297 2-1 QST Environmental


locations microwells soil vapor points soil borings monitoring wells (existing and newly

installed) stream gauges piezometers and seismic survey lines

All pertinent investigation-related features within approximately 1500 feet of the Site were

included in the survey Several surface watersediment sampling locations beyond 1500 feet from

the Site were not surveyed and their locations are estimated based on their proximity to mapped

physical features such as bridges or roads

The surveying services for this investigation were performed by KWP Associates Inc of Pomfret

Center Connecticut a licensed and registered surveyor in the State of Connecticut The survey

was completed as a third-order plane survey as defined by the standards and specifications in

Exhibit 14-1 of the Compendium of Superfund Field Operations Methods December 1987

(USEPA 1987)

22 Site Reconnaissance 221 Visual Observations of the Ground Surface

A visual reconnaissance of the Site was conducted during an approximate three week period

beginning on August 23 1994 and ending on September 13 1994 During the visual Site

reconnaissance the entire length of each trending line (shown on Plate 2-1) was walked to

identify and map any features which may have been indicative of unknown disposal areas Any

features such as areas of stained soil partially buried man-made objects remnants of buildings

abandoned equipment containers (eg drums tanks) pits depressions mounds and any other

apparent unnatural materials were photographed and noted on field maps and in a field notebook

Also potential disposal features identified during review of historic aerial photographs (Bionetics

Corporation 1990) were located and investigated The locations of features were flagged and

approximated using the survey stakes installed during the initial Site survey The results of the

field reconnaissance were also used to determine additional soil gas sampling locations (described

in Section 25) during subsequent Phase 1A investigations

222 Air Quality Survey

A baseline air quality survey was conducted prior to the start of Phase 1A intrusive field

investigations The survey was performed using a photoionization detector (PID) equipped with

an 117eV lamp to measure total VOC vapors and a direct reading aerosol monitor (RAM-1) to

measure respirable particulates Baseline air quality readings were recorded at eight stations

(AM-1 through AM-8) located across the Site The monitoring stations included areas along the

Site perimeter as well as interior locations at the three known former disposal areas The

locations of the eight baseline air monitoring stations are shown on Plate 2-2

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In addition to the baseline air quality survey air monitoring was performed on a weekly basis at the eight locations during the entire Phase 1A field investigation Wind direction wind speed

temperature and barometric pressure were also continuously monitored at an on-site

meteorological station

During the Phase IB investigation quantitive air monitoring was performed for site specific

compounds The Phase IB air sampling was performed in the vicinity of the Former Primary

Disposal Area on October 24 1995 This location was selected based on the findings of the

Phase 1A field program Four samples were collected along the perimeter of the Former Primary

Disposal Area at the northern southern eastern and western edges of the perimeter One

background sample was collected at a location approximately 300 feet south of and upwind from the Former Primary Disposal Area The sample locations are shown in Plate 2-2 The samples

were analyzed for the following volatile organic compounds (VOC) toluene ethyl benzene xylenes (total) and tetrachloroethane (PCE) and polychlorinated biphenyls (PCBs)

VOC samples were collected on stainless steel Tenax tubes which were connected to Dupont

Alpha 1 sampling pumps Samples for PCBs were collected on 037z glass fiber filters using

Dupont Alpha 1 and BIOS AirPro 6000D sampling pumps The sampling media was attached to

the sampling pumps using silicone tubing The pumps were secured to wood stakes and

positioned approximately 5 feet above the ground surface

The pumps used to collect the VOC samples were set to pump at a flow rate of between 0014 to

0016 liters per minute and allowed to pump approximately eight hours The pumps used to collect the PCB samples were set to pump at a flow rate of between 27 and 33 liters per minute

and were allowed to pump approximately eight hours All of the sampling pumps were calibrated prior to and after the sampling event using a primary gas flow mini-Buck Model M-5 Calibrator

Ambient meteorological conditions including temperature relative humidity barometric pressure

and wind speed and direction were monitored during the sampling event using ESEs on-site Qualimetrics meteorological monitoring instrument

A VOC and a PCB field blank were collected at background location AS 105 The VOC Tenax

tube and the PCB glass fiber filter were appropriately labeled opened and then immediately

resealed The field blanks were stored and shipped with the samples

At the completion of the sampling event the VOC Tenax sample tubes (including the field blank)

were sealed placed in clean plastic bags and refrigerated at 4degC until they were shipped The

samples were then shipped to the laboratory in coolers The PCB sample filters were sealed



wrapped in bubbie wrap and packed along with the PCB field blank in a cardboard box for

shipment to the laboratory An unopened VOC Tenax tube and PCB glass fiber filter were

submitted with tae samples as a trip blank The VOC Tenax sample field blank and trip blank

tubes were packed in a cooler with ice and sent to ESEs Denver Colorado Laboratory where

they were analyzed by EPA Method TO1 The PCB glass fiber sample field blank and trip

blank filters were sent to ESEs Denver Colorado Laboratory where they were analyzed by

SW846 EPA Method 8080 The results of the air quality survey are discussed in Section 44

223 Exclusion Zone Identification

Prior to the start of Phase 1A field activities preliminary exclusion zones were identified to limit

the risk of workers exposure to potentially hazardous conditions Based on existing data and

observations made during the Site visual reconnaissance the three known former disposal areas

and the area immediately surrounding a former CTDOT asphalt plant structure were staked and

flagged with caution tape A contaminant reduction zone (CRZ) was established adjacent to the

exclusion zone in the prevailing upwind direction during investigations at each location The

CRZ was established for decontamination operations of Site personnel and equipment

224 Project Support Measures

All field investigations were managed from a field office located within an approximate 10000

square foot support center which was situated at the southern end of the Site along Tarbox Road

The support center consisted of an approximate 100 foot by 100 foot area surrounded by a 6 foot-

high chain link fence The support center housed an office trailer an impermeable bermed

decontamination pad lined with 60 mil thick textured HDPE potable water storage tanks storage

units (drums dumpsters and tanks) for investigation derived wastes the weather station and

portable sanitary facilities The office trailer was connected to electric utilities and telephone

service to facilitate normal business and emergency operations A storage trailer for supplies and

equipment was located adjacent to the support center

The field office was used to support field activities by providing the following services

bull personnel sign-in and sign-out sheets

bull daily field activity log book

bull Health amp Safety log book

bull storage of Personal Protective Equipment (PPE)

bull communications center

bull posting of project plans

bull management of project field files

bull briefingmeeting room to coordinate field activities

5797wpdocsgalluprifinaltextmasterrifW061297 2-4 QST Environmental


bull meeting place for emergency evacuations and

bull lunch area

The support center also provided an access control point for the Site as it is the only practical

location where four wheeled vehicles could enter or exit the Site Other non-vehicular access

points were blocked with boulders or mounded soils Other access to the Site is limited due to

the presence of heavy vegetation steep slopes and wetlands In addition warning signs

prohibiting trespassing were posted every 100 feet along the Site perimeter prior to the start of

Phase 1A field activities

225 Identification of Sensitive Human Receptors

A survey to identify potential human receptors in the vicinity of the Site was performed This

survey was used to identify any private water supply wells schools nursing homes and day care

facilities located within a one mile radius of the Site The survey was performed by reviewing

available records and documents from the following sources

bull Town of Plainfield Municipal Offices

bull Northeast District Health Department

bull Connecticut Department of Environmental Protection

bull Connecticut Natural Resource Center and

bull Connecticut Department of Health and Addiction Services

In addition to the file reviews interviews were conducted with neighbors and knowledgeable local

people Finally a windshield survey was conducted for the area located within a one mile radius

of the Site

23 Geophysical Surveys During the Phase 1A investigation comprehensive geophysical surveys of the Site were conducted

by Weston Geophysical Corporation of Northborough Massachusetts using electromagnetic

terrain conductivity (EM) magnetometer (MAG) and seismic refraction survey techniques The

purpose of the EM and MAG surveys was to obtain Site-wide screening data to identify the

locations if any of potential subsurface disposal features or objects such as pits trenches drums

or tanks The initial EM and MAG surveys were conducted along each of the trend lines

established during the initial Site survey as shown on Plate 2-1

The purpose of the seismic refraction survey was to determine the location and orientation of the

inferred bedrock fault (if present) in the central portion of the Site Although bedrock

characterization was not one of the intended purposes of the MAG survey subsequent review of

5797wpdocsgalluprifinaltextmasterriftil061297 2-5 QSTT Environmental


the acquired MAG data provided some information regarding the nature of the shallow bedrock

surface in the central portion of the Site

The presence of heavy vegetation over much of the intended survey area required approximately

two weeks of brush cutting and clearing in order to gain access to the trending lines and to ensure

complete coverage of the Site Once the proposed survey lines were accessible the initial MAG

and EM surveys were conducted along each trending line with data collected at five-foot intervals

The Work Plan stated that the five-foot intervals would be determined by laying a fiberglass

measuring tape along each trend line between survey stakes However the presence of heavy

vegetation prohibited the efficient use of this technique Since the exact locations of any

unexplained anomalies would be later determined during subsequent EM and MAG surveys (and

confirmed during test pit explorations) it was determined that the five-foot intervals could be

efficiently and accurately estimated by an experienced equipment operator by counting paces

between intervals and making adjustments as necessary at each survey stake (which were located

every 250 feet along each line)

As stated in the Work Plan ground penetrating radar (GPR) was to be used if necessary to

further characterize any unexplained anomalies identified during the initial EM and MAG surveys

The presence of abundant vegetation and rough ground surface conditions in the areas of interest

precluded the reasonable use of GPR As approved by EPA the precise locations of unexplained

anomalies identified during the initial EM and MAG surveys were determined during additional

EM and MAG surveys using a finer (5 foot by 5 foot) survey grid superimposed over the general

vicinity of each anomaly

The seismic refraction survey was conducted along six roughly parallel lines which were placed

normal to the anticipated strike of the inferred bedrock fault The locations of the six seismic

lines are shown in Plate 2-3 Each seismic line (Line 1 through 6) is comprised of two 250-foot

long lines which overlap by 125 feet This resulted in a total of 375 feet of continuous coverage

along each line

A complete report provided by Weston Geophysical Corporation describing the theoretical basis

for these surveys is presented as Appendix A Generalized discussions describing the field

methods and equipment used during each geophysical survey are presented below

5797wpdoclaquogalluprifinaltextmastemfnl061297 2-6 QST Environmental


231 Electromagnetic Terrain Conductivity (EM) Survey

The initial EM survey was performed by Weston Geophysical Corporation over a three day

period (September 14-16 1994) using a Geonics EM-31 electromagnetic terrain conductivity

logger and a Model 720 Polycorder Background terrain conductivity readings were collected at

the beginning and end of each day from an area determined to be relatively free of electrical

interference The background station was located at the extreme southeastern corner of the Site

well away from the overhead electrical lines located along Tarbox Road and Route 12 (Norwich

Road) The EM-31 was calibrated daily by the operator and data was downloaded in the field to

a computer as needed typically twice a day

Following daily calibration the EM survey was performed by the instrument operator who paced

the entire length of each trend line with the EM meter and data logger Terrain conductivity

measurements were made and digitally recorded at five-foot intervals along each line The

presence of surficial objects and other features (eg steel fencing) that would cause interference

or produce anomalies were noted in the field notebook and accounted for during the data

evaluation Terrain conductivity data were subsequently plotted on a base map of the Site and

contoured to produce the terrain conductivity contour map included in the Weston Report in

Appendix A The results of the EM survey are discussed in Section 413

232 Magnetometer (MAG) Survey

The initial MAG survey was conducted by Weston Geophysical Corporation over a period of 7

days (September 7-14 1994) using two GEM-VI and one EGampG Model 856 magnetometers The

two GEM units were used for data acquisition while the EGampG unit was used as a base station to

monitor diurnal changes in the earths magnetic field The base station was established at the

southeastern corner of the Site where there was no interference from metallic objects or overhead powerlines and where no significant magnetic field gradients were observed

The MAG survey was performed by walking each trending line wiih one of the data acquisition

magnetometers (GEM-VI) and recording the magnetic field at every five-foot interval determined

by pacing The MAG data were eventually corrected for diurnal background fluctuations in the

earths magnetic field as determined at the base station and plotted on a base map to produce the

magnetic contour map which is included in the Weston Report in Appendix A The results of the

magnetometer survey are discussed in Section 413

5797wpdocsglaquolluprifinaltextmlaquo8terriftJ061297 2-7 QST Environmental

Gallups Quarry SuperUna1 Project - Remedial Investigation

233 Additional EM and MAG Surveys

In lieu of GPP surveys additional EM and MAG surveys were performed to determine the

precise location of any terrain conductivity or magnetic anomalies which could not be explained

by the presence of surficial metallic debris The additional surveys were performed over a 5-foot

by 5-foot grid in the vicinity of each unexplainable anomaly

A total of four unexplainable anomalies within three separate areas were eventually investigated

with additional EM and MAG surveys Once the locations of the anomalies were accurately

located each anomaly was further assessed by excavating test pits to identify the source of the

anomaly The test pit operations are discussed in Section 214 and the findings of the test pit

excavations are discussed in Section 4133

234 Seismic Refraction Survey

A seismic refraction survey was conducted along six 375-foot lines located within the suspected

fault zone An ABEM Terraloc 24-channel digital recording seismograph system was utilized for data collection The 375-foot spread lengths consisted of two overlapping 250-foot long lines

with geophones spaced in ten-foot intervals The endpoints of each seismic line were staked in

the field to facilitate the subsequent location survey

In accordance with the Work Plan shot points were located at each end point midpoint and

quarter point in addition to an offset from each end point The Work Plan had stated that

seismic energy would be produced by either an elastic wave generator or weight drop However

due to access constraints at the Site EPA approved the use of an alternate energy source For

these surveys seismic energy was generated using 8 gauge seismic shotgun shells discharged

approximately 2 to 3 feet below ground surface

The energy created by the shell blast travels through the ground and refracts along interfaces

between materials of different propagation velocity and density characteristics Interpretation of

these data on a time vs distance plot is conducted for the seismic wave arrival times at each

geophone The propagation velocities can be categorized into various geologic materials such as

overburden saturated overburden bedrock formations and weathered or fractured formations A

comprehensive discussion of the theoretical basis and operation of this technique is presented in

the Weston Geophysical report provided as Appendix A The results of the seismic refraction

survey are discussed in Section 32

5797wpdoc8gaIIuprifinaltextmasterrifnl061297 2-8 QSTEnvironmental


24 Groundwater Sampling Using Temporary Well Points Between August 29 and October 7 1994 a total of 60 small-diameter temporary well points

(microwells) were installed at predetermined locations using direct push techniques for the

purpose of collecting groundwater samples for both on-site and off-site chemical analysis At 10

of these locations equipment refusal occurred prior to encountering groundwater thus reducing

the total number of sampled locations to 50 The results of the chemical analyses were used to

determine the nature and extent (both horizontal and vertical) of groundwater contamination (VOC

and metals) within the Study Area Data obtained during this survey were ultimately used to determine the optimum location for subsequently-installed permanent groundwater monitoring

wells The surveyed locations of the temporary well points (TW101-TW160) including the 10 unsampled locations are shown on Plate 2-4 A summary of the locations and depth intervals for

each microwell is presented in Table 2-1

A total of 126 samples were analyzed on-site for selected VOC using a portable gas chromatograph (GC) A total of 121 samples (not including duplicates and field blanks) were

submitted for off-site laboratory analysis for cyanide and metals Also 12 samples (not including

field blanks and trip blanks) were submitted for off-site laboratory analysis for VOC to confirm

the on-site GC analytical data

The microwells were comprised of a 082 inch diameter (062 inch inside diameter) steel riser

pipe of varying lengths equipped with a hardened steel tip and a 5 foot long slotted section at the

leading end The 5 foot long slotted section (or screen) consisted of a four longitudinal rows of 2

inch long by 0015 inch wide slots Each microwell was advanced into the subsurface using

either an electrically or hydraulically powered vibratory impact hammer which was mounted on a

telescoping mast The mast drive-hammer and all other ancillary equipment were mounted on an all-terrain vehicle for maximum mobility

Individual sections of riser pipe (which varied in length up to a maximum of 21 feet) were

connected using a slip coupling over the butted ends of adjacent sections The slip coupling is

either electrically welded or crimped (using a hydraulic crimping tool) over the connection to

form a water tight joint

All materials were steam cleaned prior to use and only used at one location to avoid cross

contamination between sampling locations

The objective at each location was to drive the microwell into the saturated overburden and collect

a groundwater sample from three successively deeper intervals The desired sampling intervals

were as follows five feet below the top of the water table midway between the top and bottom of

5797wpdocsgalluprifinaltextmlaquoraquotemfhl061297 2-9 QST Environmental


the aquifer and at the bottom of the aquifer (ie the refusal depth) A middle andor deep sample

was not collected if refusal was encountered without significant advancement of the well point

between sample depths (minimum of 10 feet) The midpoint sampling depth was estimated based

on the refusal depths encountered at nearby microwells

Once the microwell was driven to the desired depth purging and sampling was accomplished

using a manually operated inertial pump comprised of an adequate length of dedicated 38 inch

(inside diameter) polyethylene tubing equipped with a bottom check valve In operation the

inertial pump is lowered into the screen section of the microwell and repeatedly raised and

lowered (manually) a distance of approximately one foot This reciprocating action causes water

to rise within the tube until it is ultimately discharged at the ground surface into either a bucket or

sample container Between one and three riser volumes were purged from each microwell prior

to sample collection except for the first sample (5 feet below the top of the water table) which was

collected without purging All purge water was containerized and eventually transported off-site

for treatment and disposal

Once a groundwater sample was acquired it was labelled packed in a cooler and transported to

the on-site laboratory Each sample was analyzed on-site using a portable gas chromatograph

for the following eight VOC

bull l2-dichloroethene(DCE)

bull 111 -trichloroethane (111 TCA)

bull trichloroethene (TCE)

bull benzene

bull toluene

bull acetone

bull methyl ethyl ketone (MEK)

bull methyl iso-butyl ketone (MIBK)

Groundwater samples from each location were also collected filtered through a 045 micron

filter preserved with nitric acid and submitted to an off-site laboratory for analysis for the

following metals

bull aluminum

bull arsenic

bull cadmium

bull chromium

bull copper

5797wpdoc8galluprifinaltextmasterrifhl061297 2-10 QST Environmental


bull iron

bull lead

bull manganese

bull nickel

bull zinc

Unfiltered samples were also collected preserved with sodium hydroxide (NaOH) and submitted

for analysis for cyanide In addition duplicates of 12 of the VOC samples analyzed in the field

were submitted for laboratory analysis for VOC for confirmation purposes Samples for off-site

VOC analyses were preserved in the field by addition of hydrochloric acid (HC1) to obtain a pH

less than 2

Samples for on-site VOC analyses were collected into 40 ml glass vials equipped with a teflonshy

lined silicon septum Each vial was filled capped labelled and refrigerated until it was

analyzed Samples were typically analyzed within several hours of collection Prior to analysis

the sample was removed from the refrigerator and 10 ml of water was withdrawn and discarded

The withdrawal of 10 ml of water created a headspace within each vial into which any VOC

present in the liquid would partition To complete the VOC partitioning process the vial was

then placed into a constant temperature (90 degC) water bath for a minimum of 15 minutes Just

prior to analysis a 250 micro-liter air sample was withdrawn from the headspace within the vial

by inserting the needle of the syringe through the teflon-lined septum and injected into the

portable gas chromatograph for analysis

A Photovac 10S50 portable gas chromatograph equipped with a CPCIL 5 encapsulated column

was used for on-site analysis The Photovac 10S50 gas chromatograph (GC) was filled every

morning with zero grade air and allowed to warm-up for 30 minutes prior to daily operation in

accordance with SOP 4001 and manufacturers instructions

The GC detector flow oven temperature and gain setting (sensitivity setting) were checked and

verified every morning and throughout the day Field GC standards were prepared daily by

diluting commercially available certified pure liquid chemical standards with deionized water

Three separate standards a low-concentration level a mid-concentration level and a high-

concentration level standard containing the eight select VOC were prepared in order to obtain a

three-point calibration curve Glass gas-tight syringes were used for preparation of standards and

sample injection AH syringes were decontaminated using methanol deionized water and

compressed gaseous nitrogen



The GC operating condition was checked in the morning and during the day using machine

blanks syringa blanks and standards All three standards were run with a syringe blank directly

before and after each injection after every ten samples and at least once in the morning and once

in the afternoon each day In accordance with the QAQC program and SOP 4009 a duplicate

groundwater sample was collected in the field in a separate 40 ml glass vial immediately

following the collection of the original sample The second vial was used for duplicate analyses

after every ten samples

In the event that a sample analysis showed a contaminant chromatographic peak with an area

greater than the high-concentration standard or the range of the GC operating parameters (off-

scale) a smaller aliquot (l10th the original sample injection volume) was taken from the second

vial and injected into the GC All pertinent information concerning the smaller aliquot was

recorded on the GC strip chart and in the field log book

The GC strip chart was labeled with the sample identification number or corresponding

identification information (eg sample ID syringe blank etc) All pertinent information (eg

sample ID) was recorded in a field log book

In accordance with the QAQC program all samples were kept at 4degC prior to analysis and were

analyzed within 48 hours of their collection time

A total of 23 microwells (TW101-TW123) were installed by Pine and Swallow Associates Inc of

Groton Massachusetts Due to limited ability to access certain locations with the available

equipment the remaining 37 microwells were installed by a second subcontractor MyKroWaters

Inc of Concord Massachusetts Installation logs are presented in Appendix B The results of

the microwell survey are discussed in Section 421 The microwell installations were later

abandoned by filling them with cement grout and cutting the risers off below the ground surface

25 Soil Gas Survey In an effort to identify the location of any previously unknown potential disposal areas a Site-

wide soil gas survey was conducted From September 26 1994 through October 12 1994 a

total of 106 soil gas sampling probes were installed across the Site Soil gas samples were

analyzed on-site using a portable gas chromatograph

A 100-foot sampling grid was used to systematically cover the Site however actual locations

were dependent on accessibility and the ability to advance the soil gas probes to the desired depth

beneath the ground surface Besides the sampling at the intersection of grid lines six additional

locations were investigated due to the presence of empty drums found at the ground surface

5797wpdoC8galluprifinaltextmastemfnl061297 2-12 QST Environmental

Gallups Quarry Superfiind Project - Remedial Investigation

during the Site reconnaissance or anomalies detected during the EM and MAG surveys The

extreme northeastern corner and eastern side of the Site were not included in the soil gas survey

since they are either wetlands or heavily wooded Also an approximate 15000 square foot area

just north of the Former Seepage Bed was not tested due to the presence of a large pile of

boulders The surveyed locations of each soil gas sampling point (SV101-SV206) are shown in

Plate 2-5 The locations of SV111 SV201 and SV141 are approximate based on field

measurements from surveyed locations

Each soil gas sampling probe consisted of a four inch long hardened steel combination drive

point and screen which was connected to an adequate length of 316 inch diameter polyethylene

tubing The pointscreen and tubing assembly were inserted inside a hollow steel shaft which was

then driven into the ground with an electrically powered vibratory hammer

An abundance of gravel cobbles and boulders in the central portion of the Site prohibited the

advancement of several probes to the minimum depth specified in the Work Plan (25 feet) After

discussions with EPAs oversight contractor regarding the surface conditions in this area it was

agreed that at the rocky locations the probe would be driven as far as possible (typically 15-2

feet) and a two-foot by two-foot sheet of polyethylene sheeting would be placed on the ground

surface surrounding the probe and weighted with native topsoil The purpose of the plastic sheet

was to minimize atmospheric influence during the sampling procedure

Once the point was driven to the sampling depth the hollow steel shaft was extracted leaving the

expendable pointscreen and tubing in place The small annular space surrounding the sampling

tube was tightly packed with native soil to ensure that gas samples were representative of soil

pore space and not atmospheric conditions Once the probe was in place any excess plastic

tubing was trimmed leaving approximately 15 feet of tubing above the ground surface Each

tube was clamped and sealed until it was eventually sampled typically within a few days of

installation

To collect a soil gas sample one end of a 280 ml glass sample chamber (equipped with teflon

stopcocks and a sampling septum) was connected to the tubing using a short length of silicon

tubing A battery-operated vacuum pump was then attached to the other end of the chamber and

used to draw a soil gas sample from the tubing Once a sample was acquired the stopcocks were

closed and the pump shut off The sample chamber was then transported to the on-site laboratory

for analysis

Just prior to analysis the needle of a gas tight syringe was inserted through the sampling septum of the glass chamber and an aliquot of the soil gas sample was removed The sample was then

5797wpdoclaquogalluprifinaltextma8terrifiU061297 2-13 QST Environmental


injected into the gas chromatograph for analysis A Photovac 10S50 portable gas chromatograph

was used to analyze each sample for the following 8 VOC


bull 111-trichloroethane (111 TCA)


bull benzene

bull toluene

bull acetone



The Photovac 10S50 gas chromatograph (GC) was filled every morning with zero grade air and

allowed to warm-up for 30 minutes prior to daily operation in accordance with SOP 4001 and

manufacturers instructions


verified every morning and throughout the day Field GC standards were prepared daily using

certified pure neat liquid standards from sealed vials Glass gas tight syringes were used for

preparation of standards and sample injection All syringes were decontaminated using methanol

deionized water and nitrogen


blanks syringe blanks and standards Standards were run with a syringe blank directly before

and after each injection every ten samples In accordance with the QAQC program a duplicate

soil gas sample was collected in the field in a separate glass sample chamber immediately

following the collection of the original sample After the original sample was injected into the

GC the duplicate sample from the separate glass sample chamber was injected into the GC The

data quality objective (DQO) for field analysis using the GC was maintained at or better than _+

30 relative percent difference In the event that a sample analysis showed a contaminant

chromatographic peak with an area greater than the range of the GC operating parameters (off-

scale) a smaller aliquot (I10th the original sample injection volume) was taken from the glass

sample chamber and injected into the GC AH pertinent information concerning the smaller

aliquot was recorded on the GC strip chart and in the field log book

5797wpdocsgalluprifinaltextma8teiTifiil061297 2-14 QST Environmental

Gattups Quarry Superfund Project - Remedial Investigation


identification (eg sample ID syringe blank etc) The analysis number and corresponding

identification information was also recorded in the soil gas survey field log book

All sampling equipment (exclusive of the dedicated expendable probes) was decontaminated between each sample by flushing with copious amounts of compressed nitrogen The results of the

soil gas survey are discussed in Section 41

26 Soil Borings at Disposal Areas A total of sixteen soil borings SB101 through SB116 were advanced at the three known former disposal areas Ten soil borings (SB 101 through SB110) were completed as part of the Phase 1A

investigation between October 4 and 13 1994 Six additional borings were advanced within the

Former Primary Disposal Area on November 2 1995 as part of the Phase IB investigation The

locations of the soil borings are shown on Plate 2-5 The objective of these borings was to obtain

soil samples to characterize subsurface lithology and determine the present level and distribution

of residual contaminants within each former disposal area The analyses performed on samples

collected during the Phase 1A investigation (ie SB101-SB110) included TCLTAL parameters

as well as pH (EPA Method 9045) total organic carbon (ASTM Method D 17565373) moisture

content and particle size distribution Samples collected during the Phase IB investigation

(SB111-SB116) were submitted for laboratory analyses for VOC and PCBPesticides The samples submitted for analysis and the depth intervals sampled are shown in Table 2-2 The

results of the soil boring program are discussed in Section 41 All soil boring logs are shown in

Appendix C

261 Piiase 1A Soil Borings Each boring completed as part of the Phase 1A investigation was advanced until equipment refusal was encountered using a truck mounted drill rig equipped with a 425 inch (inside diameter)

hollow stem augers The drilling operations were performed by Environmental Drilling Inc of

Sterling Massachusetts As shown in Plate 2-5 three of the borings were placed in the reported

location of the Former Seepage Bed (SB101-SB103) three were placed within the Former

Secondary Disposal Area (SB104-SB106) and four were placed within the Former Primary

Disposal Area (SB107-SB110) The Work Plan required that samples be collected and submitted

for laboratory analysis from each boring from specific depth intervals (0-1 foot 1 to 10 feet and

10 feet to the water table) and from each distinct hydrological unit encountered (eg coarse

stratified drift fine stratified drift and till) and from the capillary fringe at each disposal area

The number of samples actually submitted for analysis was dependent on the depth to water and

the number of hydrogeologic horizons encountered at each area In general samples submitted

579Twpdoc8galluprifinaltextmlaquo8terrifhl061297 2-15 QSTEnvironmental


for laboratory analysis were selected from within each depth range or horizon based on PID

readings andcr visual observations

Soil samples from the 0-1 foot interval were collected from the ground surface using a stainless

steel hand trowel All subsequent samples were collected using a standard 2-inch diameter split-

spoon sampling device in accordance with ASTM Method D-1586-84 Each sample was

screened in the field for total VOC using a PID equipped with an 117 eV lamp Each sample

was then visually classified and logged in a field notebook and on boring logs A portion of each

sample was placed into glass jars and sealed with aluminum foil and a screw cap for headspace

analysis The headspace sample was ultimately saved for archival purposes

All sampling equipment was decontaminated prior to use and between each sample using a

detergent wash and tap water rinse followed by methanol nitric acid and deionized water rinses

All drilling equipment was steam cleaned between boring locations All decontamination rinseates

were containerized and eventually transported off-site for treatment and disposal Likewise all

soil cuttings were containerized for eventual off-site disposal Upon completion each borehole

was filled to the ground surface with a bentonitecement grout mixture and marked with a labeled

stake so that its location could be surveyed

262 Phase IB Soil Borings

Data obtained during the Phase 1A investigation indicate the presence of residual soil

contamination in the vicinity of the Former Primary Disposal Area In order to more fully

characterize the extent of this residual contamination six additional soil borings were completed

along the perimeter and within the Former Primary Disposal Area These borings (SB111shy

SB116) were installed by Connecticut Test Borings Inc of Seymour Connecticut using a track

mounted drill rig equipped with a standard split-spoon soil sampler Two samples from each

boring were submitted for laboratory analysis of TCL VOC and pesticidesPCBs At each

location a surface soil sample was collected from the 0-1 foot interval and submitted for

laboratory analysis Soil samples were then collected continuously from a depth of 1 foot below

the ground surface to the water table A discrete sample from within this zone was submitted for

laboratory analysis based on PID results At locations where no elevated PID headspace readings

were encountered a sample collected from the capillary zone was submitted for laboratory

analysis

5797wpdocsglaquolluprifinaItextmraquo8terrifiil061297 2-16 QST Environmental


27 Installation of Monitoring Wells and Background Soils Sampling

Following the evaluation of data obtained during the visual Site reconnaissance and microwell

and soil gas surveys a network of monitoring wells was designed that would allow groundwater sampling and analysis and measurements of hydraulic parameters The installation of monitoring

wells at upgradient locations was also included to allow collection of background soil samples and

to determine upgradient groundwater quality

The majority of the Phase 1A investigation monitoring wells were installed by Environmental

Drilling Inc of Sterling MA A second drilling contractor Maher Environmental of North Reading MA was added in December in order to complete the monitoring well program before

the onset of winter The well installation program began on November 7 1994 and was completed on December 29 1994

The original Work Plan specified that a total of 47 monitoring wells would be installed but contemplated that the final number and locations of the monitoring wells could be adjusted based

on the findings of the preliminary screening surveys (ie the microwell and soil gas surveys)

Based on these data which were presented to EPA throughout the course of the screening surveys

EPA approved a Phase 1A monitoring well network which consisted of a total of 39 monitoring

wells at 16 locations

During the course of the Phase 1A monitoring well installation program one anticipated

intermediate depth overburden well (MW109T) was not installed because there was only

approximately 35 feet of saturated overburden encountered at that location A total of 38

monitoring wells at 16 locations were installed The surveyed locations of these wells are shown on Plate 2-6

By the end of the Phase 1A field program a total of 16 locations (or clusters) were completed

and were comprised of the following

bull (2) four well clusters (MW105 and MW107)

bull (4) three well clusters (MW101 MW108 MW112 and MW115) bull (8) two well clusters (MW102 MW103 MW104 MW106 MW109 MW113

MW114 andMW116) and

bull (2) single wells (MW110 and MW111)

(Note An additional 6 groundwater piezometers [PZ201-PZ206] were also installed)


Gallups Quarry Superjvnd Project - Remedial Investigation

To further delineate the nature and extent of contamination and to refine the hydrogeologic

characteristics within the area of investigation a total of seven groundwater monitoring wells (and

one piezometer PZ301) were installed as part of the Phase IB investigation

The wells completed during Phase IB included the following

bull (3) two well clusters (MW117 MW118 and MW119)

bull (1) bedrock well (installed at the Phase 1A location MW102)

All Phase IB monitoring wells were installed by Connecticut Test Boring Inc utilizing a track-

mounted drill rig The surveyed locations of these wells are shown on Plate 2-6

AH monitoring well labels include a suffix code (eg S TT T or B) which indicates the location

of the screened interval (or open interval in the case of bedrock wells) for that particular well

The screen interval for each prefix is

S - Shallow well in which the screen intersects the surface of the water table

TT - Top-of-Till well in which the bottom of the screen is located just above the till

horizon

T - Till well in which the screen was placed within the till horizon and

B - Bedrock well in which the overburden is sealed off with steel casing which is

grouted into the bedrock surface and the well consists of an unscreened open hole

below the top of the bedrock surface

The TT T and B designations are geologically specific (top-of-till till or bedrock) while the S

designation is depth specific Monitoring well MW109S is in fact located within a till horizon but

was designated as an S well since the screen intersected the surface of the water table Similarly

although monitoring well MW110S is designated as a shallow(s) well observations recorded

during its installation indicate that MW110S is set just below the top-of-till interval

Specifically the 45 wells completed during the Phase 1A and IB investigations included the

following

bull 18 shallow (S) water table wells

bull 13 top of till (TT) wells



bull 5 till (T) wells and

bull 9 bedrock (B) wells

271 Phase 1A Monitoring Well Placement-Rationale

2711 Phase 1A Upgradient Monitoring Wells and Background Soil Sampling

Two monitoring well clusters MW109 (S B) and MW112 (S TT B) were installed to provide

soil and groundwater samples from various depths from locations upgradient of the known former

disposal areas These data were obtained to provide chemical data which was assumed to be

representative of background conditions The general location of these two well clusters was in

accordance with the general east to west direction of groundwater flow across the Site which had

been indicated during previous investigations and by the location of the contaminant plume

identified during the microwell survey The location of MW112 cluster (south of the Former

Seepage Bed) would also serve to confirm the presence or absence of radial groundwater flow

patterns away from the Former Seepage Bed During the installation of these wells soil samples

from stratified drift and till horizons were collected and submitted for laboratory analysis for

TALTCL parameters

A shallow top of till and bedrock well were installed at location MW112 The overburden wells

at this location were successfully installed using hollow stem augers A shallow till and bedrock

well were planned for location MW109 However since only approximately 35 feet of saturated

overburden was encountered at that location only one well MW109S was installed in the

overburden

The overburden and bedrock monitoring wells at these locations were constructed in accordance

with the general procedures described above with the exception of MW109S An abundance of boulders at this location prohibited the ability to advance augers or drive casing more than several

feet below the ground surface After numerous attempts within a 100-foot radius of the desired

location a backhoe was ultimately required to excavate a pilot hole in the unsaturated zone to

approximately 8 feet below the ground surface Augers were then lowered into the pilot hole and

advanced to the refusal depth of 12 feet The overburden well was then constructed as described

in Section 273

The bedrock well at MW109 was installed using a mud rotary drilling technique to drill an

overburden pilot hole to the bedrock surface into which 5-inch diameter steel casing was lowered

and seated on the top of the bedrock surface Another pilot hole was then drilled into the bedrock

to receive the permanent 3-inch casing The bedrock was subsequently cored as described in

Section 273

5797wpdoC8galluprifinaltextmaBterriftU061297 2-19 QST Environmental


2712 Phase 1A Monitoring Wells - Former Primary and Secondary Disposal Areas

A total of nineteen ground water monitoring wells were installed in seven cluster locations at

downgradient areas relative to the known Former Primary and Secondary Disposal Areas

Monitoring wells MW102 (S TT) MW105 (S TT T B) and MW107 (S TT T B) were

located along the centerline of a groundwater contaminant plume detected during the microwell

survey and earlier studies

Well clusters MW101 (S TT T) MW103 (S TT) MW104 (S TT) and MW106 (S TT) were

located in areas believed to be beyond the edges of the contaminant plume delineated during the

microwell survey These wells were placed at these locations in an effort to define the plume

boundaries In addition the location of MW103 was selected by EPA to address historic

references to a leachate seep reportedly observed at Mill Brook west of the railroad bridge

Besides the nineteen wells described above another six monitoring wells at three locations were

installed in the vicinity of the Former Primary and Secondary Disposal Areas MW116 (S T) MW108 (S TT B) and MW110S were located north northeast and east of the former disposal

areas respectively to confirm the plume boundaries in these areas

2713 Phase 1A Monitoring Wells - Former Seepage Bed Area

A total of three monitoring wells were installed in the general vicinity of the Former Seepage

Bed A single bedrock well MW11 IB was placed west of the Former Seepage Bed within the

potential fracturefault zone identified by the geophysical studies The purpose of this well was to

assist in evaluation of whether the inferred fracturefault zone may be acting as a preferential

contaminant transport pathway from the Former Seepage Bed The location of MW113 (S B)

west of the Former Seepage Bed was selected to confirm water quality and to obtain

hydrogeological data in this area since an abundance of cobbles prohibited the advancement of

microwells into the saturated zone in this area

2714 Phase 1A Monitoring Wells - Southern Portion of the Site

Five monitoring wells located at two clusters (MW114 and MW115) were installed to determine

water quality and to characterize the hydrogeological parameters in the southern portion of the

Site Although there is no evidence to suggest that disposal activities occurred in areas of the Site

south of the Former Seepage Bed MW114 (S TT) and MW115 (S TT B) were placed to

coincide with locations at which low levels of VOC were detected during the microwell survey

5797wpdocsgalluprifinaltextmasterri fhl061297 2-20 QSTEnvironmental


272 Phase IB Monitoring Well Placement-Rationale The results of the Phase 1A investigation indicate that a well-defined low to moderate-VOC

concentration groundwater plume originates in the vicinity of the Former Primary Disposal Area

The plume is defined by the presence of certain VOC primarily TCA 12-DCE and xylene The

highest concentrations of these compounds were detected at MW107TT with decreasing

concentrations at downgradient well clusters MW105 MW102 and MW101

The compound PCE was detected in groundwater monitoring wells within the plume but its

distribution in groundwater exhibited inconsistencies with migration from the former disposal

areas In addition the observed concentrations of PCE did not coincide with the observed rate of

plume attenuation and transport rates possibly indicating an off-site source A goal of the Phase

IB investigation was to obtain additional information concerning overburden groundwater quality

and flow patterns in the area north-northwest of the Former Primary Disposal Area in order to

assess the potential for an off-site source

2721 Phase IB Monitoring Wells-Former Primary and Secondary Disposal Areas

One bedrock monitoring well (MW102B) was installed downgradient of the Former Primary and

Secondary Disposal Areas as part of the Phase IB investigation Data collected during the Phase

1A field program indicate that bedrock hydraulic gradients are generally upward across the Study

Area and that bedrock is not a preferential pathway for contaminant migration However low

concentrations of certain VOC were detected in bedrock well MW105B located downgradient of

the Former Primary Disposal Area To determine the nature of contaminant migration in bedrock

further downgradient from the source area a bedrock monitoring well was installed in the vicinity

of well cluster MW102 During the installation of MW102B soil samples were collected from

three intervals within the saturated portion of the overburden aquifer (15-17 30-32 and 45-57

feet below the ground surface) and submitted for laboratory analysis for total organic carbon

(EPA Method 9060)

2722 Phase IB Monitoring Well - North-Northwest of the Site Data obtained from CTDEP files during the Phase 1A investigation indicate that monitoring wells

located on the western and northern sides of the former Pervel flock plant (located just north of

the Site across Mill Brook) historically contained elevated concentrations of certain VOC

particularly PCE TCA and DCE A contribution of VOC in groundwater from this area could

explain at least partly the VOC detections in the wells at MW101 To confirm the potential for

groundwater flow from the former Pervel facility to the area around well MW101 and to further

refine the understanding of groundwater quality and flow in areas north-northwest of the Former

Primary Disposal Area three additional monitoring well couplets and one groundwater piezometer



were installed The Phase IB well couplets designated as MW117 MW118 and MW119

consisted of a shallow overburden well and a deep monitoring well screened above the till

horizon A groundwater piezometer designated as PZ-301 was installed in this area to provide

additional hydraulic data The surveyed locations of the seven monitoring wells and the

piezometer installed as part of the Phase IB investigation are shown on Plate 2-6

273 General Monitoring Well Installation Techniques

At each monitoring well (or cluster) location continuous soil sampling was initiated using either a

truck or track mounted drill rig equipped with 425 inch (ID) hollow stem augers and standard 2shy

inch diameter split-spoons The objective was to continuously sample and complete the deepest

overburden boring at each location using hollow stem augers A variety of subsurface conditions

(eg running sands greater that anticipated saturated overburden thicknesses and an abundance of

cobbles and boulders) prohibited the use of hollow stem augers all the way to completion depth at

many locations In order to overcome these drilling conditions EPA approved drive and wash

drilling techniques using water as a drilling fluid to complete many of the deeper overburden

monitoring wells The source of drilling water for this investigation was a nearby fire hydrant

which is connected to the local municipal potable supply system The introduction of drilling

fluids is generally avoided whenever possible as the presence of foreign fluids may cause some

dilution of any constituents which may be present The subsequent use of low-flow purging and

sampling techniques (discussed in Section 29) gave maximum assurance that samples collected

were representative of the natural formation waters

When drive and wash techniques were used the preferred casing diameter was six-inches Six-

inch diameter casing allowed the construction of a desired filterpack thickness of two inches (for

two inch diameter wells) However five-inch diameter and in some cases four-inch diameter

casing was also used primarily at locations in which access and drilling conditions prohibited the

advancement of six-inch casing in a timely and efficient manner EPA approved the use of five-

and four- inch diameter casing provided that the resulting monitoring wells were capable of

yielding low turbidity groundwater samples (which they ultimately did)

In accordance with the Work Plan continuous soil sampling was attempted at the deepest boring

at each location to provide continuous stratigraphic control However the presence of

uncontrollable running sands within certain intervals at several locations made the timely

collection of continuous viable samples extremely difficult In an effort to adhere to the original

schedule as closely as possible EPA approved lengthening the sampling frequency from

continuous to five-foot intervals at locations where running sands were encountered

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At several locations auger or casing refusal during the sampling stage was encountered above the

expected depth to bedrock (ie within or on top of the till horizon) At certain bedrock locations

which did not require further soil sampling EPA approved advancing and setting casing using

mud rotary drilling techniques In cases where drilling mud was used as the circulation media

powdered bentonite (National Sanitation Foundation International approved) was mixed with

potable water to yield a relatively thin drilling mud Once the borehole was drilled and stabilized

with drilling mud permanent steel casing was advanced and set The drilling mud was then

completely flushed from the borehole using fresh water and containerized (along with the water)

for eventual disposal In general the use of drilling mud is avoided whenever possible to

eliminate the introduction of foreign compounds in the aquifer Since drilling mud was used to

drill through overburden material (at bedrock wells only) and drilling mud was never in contact

with bedrock fractures the use of mud is not believed to have had any impact on groundwater

samples collected from these wells

All overburden monitoring wells were constructed using 2-inch diameter schedule 40 PVC well

screen and riser All screens consisted of continuous slot construction with 001-inch wide slots

The filter pack sand size grade was selected based on grain size data obtained during the soil

boring program The size-grade chosen (Morie OON) was selected in accordance with EPA

requirements (4 to 6 times the mesh size which retained 70 of the formation material) Most

screens were 10 feet long however several wells screened in till were constructed using 5-foot

long screens due to the limited thickness of the till horizon at those locations (MW105T

MW112T and MW116T) and the requirement to not install screens across different geologic

horizons Regardless of the screen length the filterpack surrounding the well screen extended a

minimum of one foot above the top of the screen A minimum two-foot thick seal of hydrated

bentonite clay was then emplaced above the filter sand pack Bentonitecement grout was then pumped from the bottom of the remaining annular space surrounding the riser pipe to the ground

surface Stainless steel centralizers were utilized to center the PVC screen within the borehole

Each well was completed with a locking 4-inch diameter steel protective casing which was

cemented in place approximately five feet below the ground surface

The bedrock wells were completed as open hole monitoring wells A minimum of four-inch

diameter steel casing was driven and seated on the bedrock surface A 3875-inch diameter pilot

hole was then drilled a maximum distance of five feet into competent rock Permanent 3-inch

diameter steel casing was then cemented into the pilot hole using tremie pipe and allowed to cure

for a minimum of 24 hours Once cured the grout inside the three inch casing was drilled out to

allow the bedrock to be cored At each location a minimum of 10 feet and a maximum of 25

feet of rock was cored using standard NX coring equipment The termination of all bedrock

wells was dependent on the occurrence of water-bearing fractures identified within the cored hole



Coring was terminated when evidence of water-bearing fractures were encountered All bedrock

wells were corHeted as open bedrock wells (ie not screened) as it appeared that the cpen holes

would not in-fl or collapse Each bedrock well was furnished with a locking 4-inch diameter

steel protective casing which was cemented in place over the permanent 3-inch diameter steel

riser

All monitoring wells were developed to remove residual particulates from the well and filter pack

and to restore the natural permeability of the formation Following well completion a minimum

of 48 hours were allowed to elapse before well development was initiated to allow the wells to

equilibrate and the grout to set Development was accomplished by overpumping various sections

of the screened interval until the field geologist determined that the pump discharge was visibly

free of particulate material Well development times varied from well to well and depended upon

the amount of fine (silt-clay) grained material at each screen interval Well development times

were usually on the order of several hours Water generated during well development was

containerized for eventual shipment off-site

All soil boring logs rock coring logs and monitoring well construction logs are provided in

Appendix C A summary table which shows survey data and other pertinent information for each

monitoring well and piezometer is presented as Table 2-3

274 Stream Piezometers and Gauges

Nine piezometers were installed at various locations within Mill Brook to monitor surface water

conditions and to determine the role of the local groundwater system in relation to stream

dynamics Water levels were recorded during several periods of the investigation to determine if

Mill Brook is a discharge or recharge point for groundwater in the vicinity of the Site In

addition five stream gauges were installed at piezometer locations PZ-1 PZ-3 and PZ-6 and at

two additional locations in Fry Brook one above and one below the confluence with Mill Brook

The locations of the stream piezometers and gauges are shown on Plate 2-6

Each stream piezometer consisted of a one-foot long slotted steel well point connected to threaded

and coupled lengths 125 inch ID steel pipe with a threaded cap The piezometers were

manually driven a minimum of two feet into the stream bed Water level readings were collected

by lowering an electronic water level indicator along both the inside and outside of the piezometer

to obtain depth to water readings for shallow groundwater beneath the stream bed and depth to

surface water respectively The stream gauges consist of a graduated steel scale attached to a

steel post which was driven into the stream bed

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275 Groundwater Piezometers

Although not specified in the Phase 1A Work Plan EPA approved the installation of six shallow

groundwater piezometers (PZ-201 through PZ-206) in the southern portion of the Study Area to

provide additional overburden piezometric data A seventh groundwater piezometer PZ-301

was installed north of the Site during the Phase IB investigation The locations of the

groundwater piezometers PZ-201 through PZ-206 and PZ-301 are provided on Plate 2-6

The seven groundwater piezometers were installed using either a track or a truck-mounted drill

rig equipped with 425 inside diameter hollow stem augers At each location the augers were

advanced and the piezometer set at approximately five feet below the top of the groundwater

table The piezometers were constructed of 1-inch diameter PVC well screen and riser equipped

with five-foot long screens Once the screen was set a sand pack was installed to approximately

one foot above the top of the screen A hydrated bentonite seal was then emplaced on top of the

filterpack The remainder of die annular space was backfilled with clean native soil and capped

with concrete Each piezometer was furnished with a lockable protective casing which was

cemented in place Upon completion each piezometer was surveyed and included in each

subsequent round of groundwater level measurements

28 Aquifer Parameter Testing 281 Grain Size Analysis

A total of 41 soil samples collected during the Phase 1A soil boring and monitoring well

installation programs were submitted for laboratory grain size analysis All grain size analyses

were performed using common sieve and hydrometer techniques in accordance with ASTM

Method D 422-63 (Reapproved 1990)

Of the 41 samples 16 were obtained from horizons described as fine stratified drift 15 were

obtained from horizons described as coarse stratified drift and 10 were obtained from horizons

described as till A total of 29 of the samples were obtained during the soil boring program

and 12 were obtained from samples collected during the monitoring well installation program

The analyses were conducted by Geotechnics Inc of Pittsburgh PA a laboratory which

specializes in geotechnical analyses A summary of the samples submitted and their depth interval

is presented as Table 2-4 The results of grain size analyses are discussed in Section 33 In

addition to grain size these samples were also submitted for laboratory analysis for pH moisture

content and total organic carbon



282 Slug Tests

Single-well variable head aquifer tests were conducted on all the wells installed during the Phase

1A investigation between January 5 and 27 1995 Rising and falling head tests were performed

on each well using a manually deployed solid cylinder or slug A pressure transducer and an

electronic data logger were used to measure and record the water level response in the well (on a

logarithmic time scale) after the slug was submerged (falling head) and removed (rising head)

Changes in water levels were recorded until the water had returned to or near the original static

level The data collected from the slug tests were analyzed to determine hydraulic conductivity

values for the screened intervals in each well The rate of change of hydraulic head was analyzed

using the Bouwer-Rice Method (Bouwer and Rice 1976) implemented in the computer program

AQTESOLV (Geraghty amp Miller Inc 1989) The results are presented in Section 33 of this

report

283 Constant Flow Tests

Constant flow tests consisting of short-term pumping tests were performed on selected

groundwater monitoring wells as part of the Phase IB investigation Constant flow tests were performed on the following wells MW102TT MW103TT MW104TT MW105TT

MW107TT MW117(S TT) MW118(S T) and MW119(S TT) In these tests an approximate

steady-state drawdown is established in the well and an analytical model of flow to a well is used

to compute hydraulic conductivity The tests were conducted using a variable speed submersible

pump and an electronic water level indicator Prior to the start of each test the static water level

was determined The tests were conducted by running the pumps at a constant known pumping

rate for short periods of time (typically less than 15 minutes) while recording drawdown until

equilibrium was reached The pumping rate drawdown and well construction details were then

used to calculate the hydraulic conductivity The results of the constant flow tests are discussed

in Section 33 of this report Field data and examples of the data reduction method are presented

in Appendix F

29 Groundwater Sampling In accordance with the Work Plan a complete round of groundwater samples was collected

following completion of the Phase 1A monitoring well installation program during January 11shy

19 1995 and is referred to as the Phase lAJanuary 1995 sampling event Subsequent

sampling events were performed as part of the Long Term Monitoring Program during April

July and November 1995 February May August and November 1996 and February 1997 As

discussed in Section 1-1 of this report individual Data Reports for all of the Long-Term

Monitoring Program sampling events (except November 1995 which was presented with the draft

RI Report) have been submitted to EPA

5797wpdoc8galIuprifin8ltextma8terrifnl061297 2-26 QZT Environmental

Gallups Quarry Suptrfund Project - Remedial Investigation

During the Phase IB field program seven new wells were installed and added to the list of wells

that were sampled (for VOC only) during the November 1995 monitoring event Six of these

wells (MW117STT MW118STT and MW119STT) were not added to the list of wells to be

sampled under the Long Term Monitoring Program although MW102B (also installed during

Phase IB) was added to the Long Term Monitoring list In addition to the wells installed during

the Phase IB investigation the following five existing wells located on the former Pervel

property were included as part of the Phase IBNovember 1995 sampling event MW-A -B -C

-2 and -3 The existing on-site wells SW-3S and SW-3D were also included in the Phase

IBNovember 1995 sampling event and the subsequent Long-Term Monitoring Program sampling

events Since the November 1995 Long-Term Monitoring event included wells that were specific

to the Phase IB investigation the November 1995 sampling event is referred to as Phase

IBNovember 1995

During the period spanning the nine sampling events discussed in this report EPA has approved

modifications to the list of wells sampled under the Long-Term Monitoring Program

Modifications to the list of wells sampled have been to delete certain wells particularly those

located in the southern portion of the Site where no site related compounds have been or are

expected to be detected After the July 1995 sampling event wells at the following locations

were eliminated from the Long Term Monitoring Program MW111 MW112 MW114 SW-9

SW-10 and SW-12 Monitoring wells located at MW110 MW113 and MW115 were eliminated

following the Phase IBNovember 1995 sampling event The following subsections describe the

field methods which have been used consistently over the nine sampling events discussed in this

report Table 2-5 shows which wells were included in each sampling event

291 Monitoring Wells The groundwater sampling locations are shown on Plate 2-4 Low-flow purging and sampling

procedures were used to collect groundwater samples in an effort to obtain turbidity-free samples

and to minimize disturbance of the natural formation

The following sequential procedures were employed during the groundwater sampling effort

1) The static water level was measured using an electronic water level indicator

2) The absence of LNAPL was visually confirmed by observation of a sample

collected using a clear plastic bailer

3) All 2 inch diameter (or larger) monitoring wells were sampled using a stainless steel electric submersible pump (Grundfos Redi-Flo 2) equipped with teflon



discharge tubing To initiate the purging procedure the intake for the pump was

owered into the mid-section of the well screen For wells smaller than 2 inch

aiameter (ie existing SW- series wells) Teflon tubing equipped with a bottom

check valve was used to inertially purge the well

4) Water was purged from the well at a low flow rate (approximately 05 litersmin)

which was continuously monitored The water quality field parameters

(temperature pH conductivity and turbidity) were monitored during the purging

process until they had stabilized within 10 over three consecutive readings

5) Once the parameters had stabilized (or a minimum of five well volumes had been

purged) groundwater samples were collected for laboratory analysis Samples

were collected from the discharge end of the pump tubing by directly filling the

appropriate sample containers in the following order VOC SVOC (including

pesticides and PCB) metals inorganic compounds At wells that did not stabilize

below the 5 NTU turbidity requirement additional metals samples were collected

filtered through a 045 micron filter and submitted for dissolved metals analyses

(in addition to total metals)

6) Samples were collected from the upper and lower portion of each well using a

clear plastic bailer to visually assess the potential presence of NAPL

All sampling equipment was decontaminated between sampling events All purge water was

containerized for eventual off-site disposal

Duplicate samples matrix spikes matrix spike duplicates field blanks and trip blanks were

included as part of the QAQC procedures All groundwater monitoring sampling forms are

included as Appendix D Most groundwater samples were submitted for TALTCL VOC SVOC

pesticidesPCB and metals although a small number of samples collected during the Phase

lAJanuary 1995 and April 1995 event were submitted for VOC SVOC pesticidesPCB and

metals by Appendix IX methods Also certain samples were selectively submitted for VOC

analyses by Method 5242 The analytical methods for each sample submitted for laboratory

analysis are shown in Table 2-5

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292 Residential Wells A total of fourteen private drinking water supply wells (DW101-DW114) were scheduled to be

sampled as part of the groundwater sampling program However two of the residences (DW101

and DW112) were unoccupied and inaccessible at the time of each of the sampling events The

residential wells are located along the eastern perimeter of the Site along Route 12 (Norwich

Road) adjacent to the southern portion of the Site along Tarbox Road and along Lillibridge

Road well south of the Site The residential well sampling locations are provided on Plate 2-5

In accordance with the Long-Term Monitoring Program the residential wells were sampled on a

semi-annual basis during the regularly scheduled summer and winter quarterly sampling events

In addition to the Phase lAJanuary 1995 sampling event residential groundwater samples were

collected during July 1995 February 1996 and August 1996 as shown in Table 2-5

Prior to the collection of groundwater samples from the residential wells a visual survey was

conducted to identify the sampling point closest to the well and to determine if any treatment

systems were in use A description and sketch of the supply system was recorded in field

notebooks Each system was opened and allowed to drain for approximately 15 minutes to purge

the plumbing system and obtain representative samples Field parameters were recorded during

purging to determine when stabilization had occurred The groundwater samples collected from

the residential wells were submitted for laboratory analysis of TCL SVOC pesticides PCB TAL

metalscyanide and VOC using EPA Method 5242

210 Surface Water and Sediment Sampling As part of the Phase 1A Investigation surface water and sediment sampling was conducted on

September 13-16 November 22 and December 29 1994 Although all locations were originally

sampled during the September sampling event three samples were lost in transit and had to be reshycollected A total of seventeen sample locations along Mill Brook and unnamed tributaries (UB1shy

UB10 and LB1-LB2) Fry Brook (FBI) Packers Pond (PP1-PP3) and a small pond along Tarbox

Road (TR1) were included in this program The re-sampled locations were UBS and UB6 (112294) and TR1 (122994) Due to dry conditions surface water samples could not be

obtained from the following locations UBS UBS UB6 UB7 and PP1

In accordance with the Long Term Monitoring program additional surface water samples were

collected during the April 1995 November 1995 May 1996 and November 1996 sampling

events to coincide with the approximate seasonal high- (ie spring) and low-water (ie autumn)

periods Following the initial Phase lAJanuary 1995 sampling event and per the request of

EPA the location of UB6 was moved due south to Mill Brook and renamed UB6A The surface

watersediment sample locations are shown on Plate 2-6 Sample locations by date are shown on

Table 2-5

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Surface water samples were collected using the actual laboratory sample containers by direct

immersion into the water Parameters which required the use of preservatives (eg metals

requires the addition of nitric acid to the sample) were collected in a stainless steel beaker and

transferred directly to the sample container to prevent loss of the preservatives during sampling

All sampling equipment was decontaminated after each use and placed into clean plastic bags

before moving on to the next station Surface water samples were collected starting at the most

downstream locations and progressed in order upstream The surface water samples were

submitted for laboratory analysis for TCLTAL compounds VOC and the following wet

chemistry parameters total organic carbon total dissolved solids total suspended solids hardness

and alkalinity The samples collected during April 1995 November 1995 and May 1996 were

also submitted for laboratory analysis of SVOC pesticides and PCBs The following field

measurements were also collected as part of the sample collection temperature conductivity

pH dissolved oxygen and turbidity

In addition to surface water during September 1994 sediment samples were collected at each of

the 17 locations (including the dry locations referenced above) Samples were collected at a depth

of 0 - 8 below the surface using manually operated soil or mud augers which were

decontaminated between sample locations The sediment samples were collected starting at the

most downstream locations and progressed in order upstream The sediment samples collected

contained greater than 30 percent solids based on visual and manual determination Samples were

submitted for laboratory analysis for TCLTAL compounds and for total organic carbon

Physical stream bed parameters (width depth and flow rate) were measured at surface water

sampling locations where discernable flow occurred This task was completed in April 1995

since the stream was at extremely low flow stages during the September 1994 sampling round

and a number of surface water sampling locations were nearly dry During the April 1995

surface water sampling event stream flow conditions were such that flow rates could be measured

at the following 5 locations UB4 UB6A UB9 UB10 FBI Locations at Packers Pond and the

small pond on the south side of Tarbox Road (TR-1) were not subject to these stream

measurements

Stream width and depth measurements were made using a fiberglass tape measure Depth and

stream flow measurements were recorded at the midpoint and quarter-points across the stream

Stream flow measurements were recorded using a Swoffer model 2100 in-situ flow meter The

flow meter was mounted on a graduated aluminum shaft which was equipped with an electronic

digital readout To calculate stream-flow the average cross-sectional area in square feet was

multiplied by the average water velocity (feetsec)

5797wpdocsgraquolluprifinaltextmasterrifhl061297 2-30 QST Environmental


211 Wetland Soil Sampling In early September 1994 samples of wetland soils were collected from 10 locations within the

Study Area These sample locations (QW1-QW10) are shown on Plate 2-6 (and on Plate 3-14

which shows delineated wetlands as discussed in Section 341) Each sampling station was

marked with labeled stakes which were eventually included in the Site location survey The

samples were collected at locations situated near the edge of the wetlands at depths within one foot of the water table and below the organic mat The samples were collected using manually

operated soil or mud augers which were decontaminated between sample locations The samples were submitted for analysis of TCLTAL compounds and total organic carbon The results of the

wetland soil sampling program are discussed in Section 43

212 Evaluation of Existing Monitoring Wells As part of the Phase 1A investigation the remaining 11 monitoring wells installed during the

1978 Fuss and ONeill Inc investigation were evaluated to determine which wells could provide

usable water level data The present condition of each well was documented and a water level and total depth measurement were taken and compared to well construction logs If the wells

were determined to be potentially viable an attempt was made to test them for hydraulic

responsiveness by conducting rising and falling head slug tests Several of the wells were missing

protective casings had been broken off below the ground surface or had infilled with sediment

The results of the hydraulic evaluations are presented in Section 33 The locations of the

remaining existing monitoring wells are shown on Plate 2-4

A summary of the condition of each existing monitoring well is presented as Table 2-6 The

majority of the existing wells are presently in poor condition Most of these wells are lacking

surface seals andor adequate protective casings Several of the wells have no protective casings at all and are comprised only of PVC riser which is broken at or near the ground surface

Based on the present total depths of several of these wells compared to their total depths at the time of construction it is evident that the screen section of several of these wells have infilled

with sand or silt Based on their present condition and the fact that new monitoring wells have

been installed ESE recommended that any of the existing wells not included as part of the Long-

Term Monitoring Program be properly abandoned Following this recommendation EPA

approved the abandonment of the following wells SW13 SW14 SW17S D and SW18 Also

the protective casings at existing wells SW-3S SW-3D SW-9 SW-10 and SW-12 were repaired

since these wells are used to measure groundwater elevations as part of the Long-Term

Monitoring Program



213 Ecological Assessment 2131 Wetlanl Delineation

A wetland delineation was conducted on Site and focused primarily on the wetlands located north

and west of the Study Area This survey was limited to the Site side of Mill Brook up to the

present channel In order to meet both Federal and State requirements two methods were used to

delineate the Study Area wetland boundaries In accordance with federal requirements wetlands

were delineated using US Army Corps of Engineers (COE) methods Since the State of

Connecticut recognizes a slightly different methodology for wetland delineation the services of a

soil scientist certified by the Society of Soil Scientists of Southern New England were also

required The only difference between the two methods is that while the COE requires analysis

of vegetation composition hydrology and hydric soil indicators the State of Connecticut requires

only the analysis of hydric soil indicators

Jurisdictional wetland boundaries were determined by evaluating several points along the

hydrologic gradient Vegetation soil and hydrology criteria were measured or observed to

determine whether the point was within or above the Jurisdictional wetland boundary In order

for an area to be judged Jurisdictional wetland criteria must be met for all three parameters (ie

vegetation hydrology and soil)

21311 Vegetation

Wetland criteria for vegetation was based on the National List of Plant Species That Occur in

Wetlands (Reed 1988) Dominant plant species were identified at the observation point and listed

on data forms for routine on-site wetland determination The stratum where the plant occurred

(canopy shrub or herb) and indicator status for that plant were recorded A dominance of

wetland indicator species indicates that the vegetation criteria is met A dominance of upland

indicator species indicates that wetland criteria are not met

21312 Hydrology

Hydrologic criteria includes the visual observation of surface water inundation soil saturation or

indirect indication of previous saturation or inundation Indirect evidence includes watermarks

(stain lines on vegetation or structures) drift lines (debris deposited in a line at the high water

mark) sediment deposits and drainage patterns within wetlands

21313 Hydric Soils

The identification of hydric soil criteria includes soil types named as hydric by USDA Soil

Conservation Service or the presence of hydric indicators within the soil profile Indicators

include mottling or streaking of organic materials high organic content the presence of sulfitic

material soil colors (gleyed colors) and others

5797wpdoc8galluprifinaltextmasteirifhl061297 2-32 QSTEnvironmental


2132 Plant and Wildlife Survey

The objective of the Phase 1A ecological assessment was to qualitatively identify any real or

potential impacts to local ecological receptors within the Study Area or otherwise influenced by

the conditions originating at the Site All observations on plants and animals were noted in field

logs during the wetland delineation

The results of this survey will assist the EPA in the performance of a more formal ecological risk

assessment During the ecological risk assessment sediment soil water and air quality data and

observations of plant and animal communities will be used (see also Section 123) to identify any areas where impacts have occurred The results of the qualitative plant and animal survey

conducted during the wetland investigation are discussed in Section 34 of the text

214 Test Pit Explorations In lieu of ground penetrating radar surveys (as discussed in Section 233) and with EPA

approval additional EM and MAG surveys were performed over a five-foot by five-foot grid in

the vicinity of unexplainable anomalies which were detected during the initial EM and MAG

surveys Once accurate locations for the anomalies were determined and marked on the ground

surface test pit explorations were conducted to confirm the source of the anomalies

On December 21 1994 test pits were excavated at a total of four locations at which

unexplainable anomalies were detected The test pits were performed under the observation of

EPA oversight contractor personnel The locations of the four anomalies and associated test pits are shown on Plate 2-7 At each anomaly a trench (or series of trenches) was systematically

excavated in one to two foot lifts using a backhoe The trenches were oriented to intersect the

longest axis of each anomaly to maximize the possibility of unearthing the source of the anomaly Once a lift was complete soil obtained from the trench walls as well as that obtained from the

backhoe bucket was screened with a PID for evidence of VOC The excavated soil and the trench

itself were also visually monitored for objects capable of producing the anomalies detected during the geophysical surveys and for other features possibly associated with disposal activities (eg

stained soil)

Once the source of each anomaly was discovered the object was excavated and the test pit was

backfilled and regraded with clean soil obtained from the excavation Since no elevated PID

readings or other signs of disposal features were encountered during the test pit operations no

soil samples were submitted for laboratory analysis Test pit logs for these excavations are

presented in Appendix E



30 Physical Characteristics of the Study Area

31 General Characteristics 311 Regional Physiography

The Site is located along the eastern border of the Quinebaug Valley Lowland This regional

feature is dominated by the southerly flowing Quinebaug River and is comprised of a north-south

trending lowland area which is approximately 2 to 3 miles in width and approximately 25 miles

long The Quinebaug River originates at headwaters located in central Massachusetts and

terminates at Norwich Connecticut where it merges with the Shetucket River approximately 12 miles south of the Site The confluence of these two rivers form the Thames River which flows

to the south approximately 15 miles and ultimately discharges into Long Island Sound

The region is characterized by relatively low relief and numerous glacial features The regional

landscape is significantly influenced by the structure of the underlying crystalline metamorphic

bedrock which is discontinuously overlain by Pleistocene glacial sediments of variable thickness

Lowland surficial features are characteristic of late Pleistocene glacial retreat processes and

include numerous kettleholes and swamps many of which are interconnected by a network of

slow draining streams

Land surface elevations in the vicinity of the Site range from approximately 150 to just over 220

feet above sea level Lowlands are bounded to the east and west by upland terrain which consists of irregular hilly areas of moderate relief The uplands contain many areas with large bedrock

ledges generally thin glacial deposits (predominantly till) poorly drained valleys and small

isolated swamps Elevations in the uplands range from 200 to 600 feet above sea level

312 Study Area Physiography

The topography on the Site is highly irregular primarily due to past quarrying operations

Numerous overgrown mounds of earthen materials (eg crushed stone sand and gravel) and

excavated depressions are scattered throughout the Site Visual reconnaissance and a number of

screening surveys (eg soil gas and surface geophysical investigations) have confirmed that many

of the features previously identified from the review of historic aerial photographs as potential

disposal areas (Bionetics 1990) were in fact features remnant of quarrying and former CTDOT

operations

The ground surface on the Site (shown on Plate 3-1) generally slopes from east to west and to a

large degree is controlled by the underlying bedrock surface The highest point within the Study

Area consists of a bedrock high overlain by a thin veneer of till and is located in the eastern

5797wpdoclaquogalluprifinraquoltextma8terri fhl061297 3-1 QST Environmental


central portion of the Site Elevations in this vicinity peak at approximately 230 feet above sea

level

The northern portion of the Site which includes the Former Primary and Secondary Disposal

Areas consists predominantly of open sparsely or non-vegetated areas of sand and gravel This cover material is presumed to have been distributed over the ground surface following CTDEP

Site remediation efforts in 1979 Presently the Former Primary and Secondary Disposal Areas are visible as roughly circular depressions which are approximately 150 feet and 60 feet in

diameter respectively The depressions are approximately 8 to 12 feet deep relative to the

surrounding ground surface These depressions intermittently contain as much as several inches

of standing water which accumulates during periods of heavy precipitation The bottoms of the

depressions are lightly vegetated with various grasses and weeds

North and west of the Site the ground surface elevation decreases as the Mill Brook floodplain is

encountered The floodplain area consists of low lying heavily vegetated wetland areas which

are periodically inundated

Excluding the isolated topographic high spot at the eastern margin of the Site the southern

portion of the Site (from the vicinity of the Former Seepage Bed to Tarbox Road) can be

described as generally flat but includes numerous man-made small-scale features such as

mounds or depressions

313 Surface Water Features

The Site is centrally located within the Mill Brook drainage basin which encompasses

approximately 18 square miles The Mill Brook drainage basin is part of the larger Quinebaug

River regional drainage basin Mill Brook a tributary to the Quinebaug River is located 250 feet

north of the Site and flows from east to west Approximately 1000 feet northwest of the Site (in

the vicinity of the Plainfield municipal sewage treatment plant) Mill Brook is joined by Fry

Brook which flows from the north Packers Pond which is located approximately 3000 feet

west of the Site was formed by the construction of a dam across Mill Brook

There are no surface water bodies located on the Site itself although several low areas (which

were excavated during previous site activities) have been observed to contain ponded water during

periods of extended precipitation

Surface water flow rates (determined during the April 1995 sampling event) were determined for

the following five locations in Mill Brook UB4 UB6A UB9 UB10 and at FBI in Fry Brook

Along Mill Brook flow rates ranged from approximately 23 cubic feet per second (cfs) at the

5797wpdocsgalluprifinaltextmasterrifnl061297 3-2 QSTEnvironmental


most upstream location (UB4) to approximately 31 cfs at the most downstream location (UB10)

Along the northern Study Area a 3 cfs increase was observed from Stations UB6 to UB10

representing a flow rate increase of about 025 cfs per 100 feet of stream length The flow rate in Fry Brook (Station FBI) was approximately 16 cfs

314 Climate The Site is located within Connecticuts Central climate division According to published

National Weather Service data (USGS 1993) the average annual temperature is approximately

50degF the coldest month is January with an average temperature of 258T and the warmest month is July with an average temperature of 714degF Annual precipitation at nearby recording

stations (located in Norwich CT and North Foster RI) averages approximately 53 inches per

year and ranges between approximately 41 and 68 inches per year (based on historic data from

1978 to 1991) The monthly distribution of precipitation is relatively even throughout the year

32 Geology 321 Regional Surficial Geology

The surficial or overburden deposits in the area consist of unconsolidated materials deposited as a

result of glaciation during the Pleistocene epoch Various glacially-derived materials including till meltwater or stratified drift deposits and post-glacial deposits of floodplain alluvium

comprise the major surficial geologic units in the vicinity of the Site Areas covered by eolian dune deposits are also noted on surficial geologic maps of the area although no dune deposits are

found within the Study Area

Till deposits in the region consist of non-sorted and generally non-stratified mixtures of sediments

with grain sizes ranging from clay to boulders Till is formed by the direct deposition of ice debris on the land surface Generally the color and lithology of till is dependant upon the

composition of local surficial deposits underlying bedrock and northerly adjacent bedrock from

which the till was derived Tills deposited during two periods of glaciation are present in the

region and blanket the bedrock surface in various thicknesses The most extensive and prevalent

till which is commonly present in surface exposures was likely deposited during late

Wisconsinan glaciation (USGS 1995) This till is referred to as upper till and is described as

predominantly loose to moderately compact generally sandy and frequently stony

A less commonly exposed lower (older) till was deposited during earlier glaciation possibly during the Illinoisan or early Wisconsinan glaciation periods The lower till is generally compact

to very compact and is typically finer-grained and less stony than the younger upper till A

weathered zone is usually present between the two till units

5797wpdoc8gnlluprifinaltextmasterrifnl061297 3-3 QST Environmental


Directly overlying the till (or bedrock where till is absent) are glacial meltwater deposits

collectively referred to as stratified drift These deposits consist of poorly to well sorted

assemblages of gravel sand silt and clay which were deposited by glacial meltwater during the retreat of the last ice sheet Variations in the composition structure and texture of the stratified

drift deposits are dependent upon the depositional environment in which they formed Deposits exhibiting a relatively high degree of sorting andor stratification can usually be classified as

either glaciofluvial (stream) deposits glaciodeltaic (where streams entered glacial lakes) deposits or glaciolacustrine (lake bottom) deposits The horizontal and vertical contacts between these

deposits are generally transitional and were dependent upon the available sediment load and

proximity to the various depositional environments (eg streams or lakes) associated with the

retreating ice front For example coarse-grained deposits of sands and gravel were usually

deposited proximal to the ice margin while further away primarily in glacial lakes deposits of

fine sand silts and clay were prevalent Poorly sorted deposits of relatively coarse material were

typically deposited at the ice front or along bedrock valley walls During the glacial retreat

these deposits would be left behind or collapsed on any underlying deposits Contemporaneously bedrock valleys were frequently dammed by glacial deposits andor masses

of glacial ice behind which glacial meltwater could accumulate forming glacial lakes Gradual

retreat of the ice margin as well as the formation (and eventual draining) of glacial lakes over

time would result in changes in the depositional environment which are seen as textural changes in the stratified drift deposits

Postglacial deposits of sand gravel silt and organic materials are also present as floodplain

alluvium along streams and rivers in the region The texture of alluvium varies over short

distances both laterally and vertically and is generally less than 5 feet thick along small streams

Since alluvial material typically represents re-worked glacial deposits the alluvium is often similar to the surrounding parent glacial material

322 Local Surficial Geology

The Study Area is located on the eastern flank of a pre-glacial bedrock valley and is bounded to

the east by bedrock-controlled upland areas and to the west by an area known as the Quinebaug

Valley lowlands Following the last period of glaciation (in which the relatively thin veneer of till

was deposited) various temporary depositional environments existed as a result of the presence of

an ice and sediment dam approximately 10 miles south of the Study Area which caused the

formation of a glacial lake Evidence of the lake (referred to as Glacial Lake Quinebaug) is well

documented in the literature (Stone amp Randall 1977) As the ice sheet retreated northward deposits left behind were dominated by sand and gravels associated with the formation of a series

of progressive and coalescing deltaic complexes which developed within the rising lake In lower

lying areas where deltas did not form finer-grained sand silt and clay was deposited Although

5797wpdocsgalluprifinaltextma8terrifhl061297 3-4 QSTEnvironmental


much of this sediment may originally have been deposited with some degree of structure or

sorting much of the structure was lost (collapsed) when the ice mass eventually melted away

The depositional environment was further complicated by the presence of residual ice blocks left

behind during the retreat of the main body of the glacier As the various depositional features

formed around these ice-blocks their eventual melting left behind depressions or kettles into

which fine sediment could settle While many kettles were eventually filled many remain as

detached or poorly drained ponds

As a result of the depositional history of the Study Area the primary surficial or overburden

deposits encountered are till and stratified drift Depending upon location the stratified drift may

be generally broken down into fine (eg silt and fine sand) or coarse (eg sand and gravel)

grained components but at many locations the change is transitional and subtle in both vertical

and horizontal directions The thickness of the stratified drift deposits ranges from non-existent

up to approximately 70 feet At some locations distinct structure is exhibited while at other

locations the structure has collapsed Post-glacial alluvial floodplain deposits were encountered

at locations within the present Mill Brook floodplain however the overall significance of these

deposits is minor

To illustrate the local geological features a series of geologic cross-sections have been prepared

At several locations lithologic data from pre-RI wells (both on-site and off-site) were

incorporated for additional detail The boring logs from which the cross sections were prepared

are included in Appendix C

As shown in cross-sections A-A B-B C-C D-D E-E and F-F (Plates 3-2 through 3-5) till

was encountered just above the bedrock surface at nearly every location The till horizon ranges

in thickness from approximately 10 to 20 feet with the thickest accumulations located along the

centrally located topographic high Surficial exposures of glacial till were observed within the

central portion of the Site as seen in cross sections A-A and C-C The till observed within the

Study Area is comprised of a fine sandy matrix containing abundant gravel cobbles and

boulders The till deposits seen in the topographically higher areas (ie elevations greater than

approximately 160 feet) were for the most part unsaturated Although reference literature for

this area (USGS 1995) describe the possible presence of two different till horizons no apparent

differentiation was observed at the site

As seen in the boring log from MW111 deposits of till are exposed at the ground surface and in

the central area of the Site However as shown on cross sections A-A and C-C (Plate 3-2) and

D-D (Plate 3-3) the bedrock surface drops off rapidly in southerly westerly and northerly

directions where relatively thick accumulations of stratified drift have been deposited over the till

5797wpdocsgalluprifinlaquoltextmalaquotemfhl061297 3-5 QFT Environmental

Gallups Quarry Superftind Project - Remedial Investigation

Within 500 feet of the central portion of the Site the overall thickness of the stratified drift

deposits increase to nearly 70 feet In the vicinity of MW113 (west of the central portion of the

Site) the lower portion of the stratified drift is comprised of approximately 30 feet of very fine to

medium-grained sand with occasional thin layers of silt This deposit appears to increase in

thickness towards the west while it thins towards the central portion of the Site where it pinches

out against the till Overlying these fine-grained deposits are approximately 30 feet of poorly

structured sand and gravel which includes abundant cobble sized material The coarser upper

stratified drift material also thins eastward towards the Site where it is in contact with the till

The coarse upper material is generally unsaturated with the groundwater table occurring at the

approximate upper surface of the fine sand

The southern portion of the Study Area is shown on cross sections A-A (Plate 3-2) and D-D

(Plate 3-3) As indicated on the southern end of cross section A-A approximately 35 feet of

stratified drift overlies the till in the vicinity of MW112 Although much of the stratified drift at

MW112 is relatively coarse an approximately 12 foot thick layer of fine-grained sand and silt is

present from about eight to twenty feet below the ground surface From MW112 the thickness of

the stratified drift thins to the north where it contacts the central topographic high

From the southeastern corner of the Site near MW112 the bedrock surface slopes downward

towards the west-southwest to a depth of approximately 75 feet below the ground surface (as seen

at location MW115 on the southern end of cross section D-D[Plate 3-3]) At MW115

approximately 65 feet of stratified drift (comprised of a sandy matrix containing a significant

amount of coarser gravel and cobbles) overlies approximately 10 feet of till

As seen in cross section B-B (shown on Plate 3-4) and A-A (Plate 3-2) the northeastern portion

of the Site (in the vicinity of the Former Primary Disposal Area) is comprised of fairly well

sorted fine- to medium-grained sand with occasional thin lenses of very fine sand and silt The

lenses of finer-grained materials appear only locally in the vicinity of MW107 and MW108 at a

depth of about 25 feet and are typically only a few inches to a few feet in thickness with limited

lateral extent Beneath the fine-grained sand and silt and directly overlying the till is 10 to 20

feet of coarser-grained sand and gravel Moving westward along cross section B-B in the

vicinity of MW105 the fine-grained sand thins and grades into coarser sand and gravel deposits

The coarse sand and gravel deposits directly overlie the till and thicken to nearly 50 feet towards

the west in response to the downward slope of the bedrock surface This portion of the Study

Area which is northwest (and downgradient) of the Former Primary and Secondary Disposal

Areas is overlain by a thin veneer of recent alluvial and swamp deposits associated with the

present Mill Brook channel and floodplain As shown on the cross section (B-B) the stratified

drift deposits in this area are very nearly saturated throughout their entire thickness

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North of the Former Primary Disposal Area (along the northern end of cross section D-D) the

bedrock surface continues to gradually slope downward (to the north) until the approximate

location of MW116 North of MW116 the bedrock surface is interpreted as appearing to rise

based on the depth to till deposits encountered beneath MW119 Stratified drift deposits

immediately north of the Former Primary Disposal Area in the vicinity of MW116 are dominated

by approximately 25 feet of fine grained sand and silt Further north along section D-D the

finer sand and silt deposits thin and are overlain by coarser grained sand and gravels Relatively

thin post-glacial stream alluvium and modern swamp deposits associated with Mill Brook are also

seen in the vicinity of MW116 and MW119 A roughly east-west cross section (E-E [Plate 3-5])

has been prepared to illustrate the lithologic features in the area north-northwest of the former

disposal areas This cross section starts at MW119 (described above) and runs west to MW101

in a line approximately parallel to Mill Brook The fine sandsilt deposit seen in the vicinity of

MW119 is also observed to the west at MW117 at the same approximate thickness and elevation

Westward from MW117 the fine sandsilt deposit grades into the more prevalent coarse sand and

gravel deposits observed at MW118 and MW101 The northernmost cross section (F-F [Plate 3shy

5]) extends westward from MW3 (located just east of the former Pervel flock plant) to PZ301

As shown on F-F this portion of the Study Area is dominated by collapsed coarse sand and

gravel deposits at least to the completion depths of the borings (MW3 MWC and PZ301) along

the line

323 Regional Bedrock Geology

Bedrock in the vicinity of the Site is mapped as a lower member of the Quinebaug Formation

which is composed of metasedimentary and metavolcanic rocks of Paleozoic age The Quinebaug

Formation is part of the Putnam Group and exhibits a sillimanite grade of metamorphism The

bedrock consists of primarily light to dark grey fine- to medium-grained hornblende gneiss biotite gneiss and amphibolite Bedrock in the area is strongly faulted and folded and exhibits

varying degrees of mylonitization A major fault zone known as the Lake Char fault is located

approximately 03 miles east of the Site The Lake Char fault is a north-south trending fault

which offsets rock units of the Putnam Group and the Hope Valley Alaskite Gneiss formation A

northwest-trending fault is shown on the USGS Bedrock Geologic Map (Dixon 1965) of the

Plainfield Quadrangle in the vicinity of the Former Seepage Bed The existence and approximate

location of the suspected fault was based on aeromagnetic data published in 1965 (Boynton amp

Smith 1965) Bedrock located north of the inferred fault is mapped as more intensely

metamorphosed cataclasites and blastomylonites The fault is mapped as extending into the Tatnic

Hill formation to the west but is not mapped within the Hope Valley Alaskite Gneiss formation

which is located to the east



324 Local Bedrock Geology

Confirmed depns to bedrock were determined based on the elevations of bedrock outcrops and

the collection of bedrock cores at nine boring locations (MW102B MW105B MW107B

MW108B MW109B MW111B MW112B MW113B and MW115B) Inferred depths to

bedrock were made at seven additional locations (MW101 MW102 MW103 MW104 MW114

MW116 MW117 MW118 and MW119) based on boring data obtained during the drilling of the

deepest wells at each cluster (which indicates the minimum depth to bedrock) and based on trends

seen at the confirmed depth locations Based on this evidence it is likely that unconfirmed depths

to bedrock are accurate to within several feet of the actual depths At MW110S no attempt was

made to advance the boring more than about 12 feet below the ground surface (the depth needed

for the required shallow well at that location) Depths to bedrock ranged from approximately 13

feet at MW111B to 83 feet at MW113B Drilling difficulties associated with the presence of

boulders just below the ground surface at MW11 IB made it difficult to determine the exact depth that bedrock was first encountered at this location Suspected boulders were encountered starting

at approximately six feet below the ground surface and casing was driven to a refusal depth of

approximately 15 feet before bedrock coring began

Based on the data described above a bedrock surface contour map is shown on Plate 3-6

Bedrock elevations are highest in the eastern central portion of the Study Area and decrease to the

north and west and to a lesser degree to the south

Within the Study Area bedrock consists of grey fine- to medium-grained gneiss with varying

contents of amphibolite biotite and hornblende Various degrees of weathering and competency

were also observed Detailed rock core descriptions are presented on the rock coring logs

provided in Appendix C

The primary objective of the seismic refraction survey (discussed in Section 234) was to

identify if present the location of a possible bedrock fault suspected to exist hi the vicinity of the

Former Seepage Bed As discussed in Section 323 the approximate location of the suspected

fault was estimated from the regional USGS Bedrock Geologic Map based on an aeromagnetic

survey conducted in 1965 Ground penetrating radar surveys conducted by the USGS (1995)

identified a northward dipping subsurface reflector beneath the central portion of the Site This

reflector was interpreted as a potential bedrock fault feature The relatively high strength of the

reflector was attributed to fault gouge (or other infilling) material or possibly sorbed inorganic

compounds No subsurface explorations were conducted at the time of the USGS investigation to

confirm the nature of the radar reflector

5797wpdocsgalluprifinaltextmiiraquoterrifnl061297 3-8 QST Environmental


Evaluation of data obtained from the seismic refraction survey indicates the presence of possible

bedrock fractures on seismic lines 3 through 6 (Plate 3-7) In addition to these interpreted

fracture zones the overall relatively low seismic velocities (12000 ftsec vs 15000 to 18000

ftsec for intact crystalline rock) indicate that in general the rock is somewhat fractured

Although the original intent of the magnetometer (MAG) survey was not to interpret bedrock

features data obtained during the MAG survey (which covered a much larger area) indicate the

presence of several linear-shaped sharp magnetic gradients bounding a zone with a different

magnetic signature The change in magnetic signature was interpreted as potentially associated

with changes in bedrock lithology and fracturing across a broad faultfracture zone in the central

portion of the Site These interpretations are described in further detail in the Weston

Geophysical Report included as Appendix A The locations of the magnetically determined

bedrock features are also shown on Plate 3-7 While the seismically interpreted fractures do not

strongly coincide with linear features seen in the MAG data they do lie within the magnetically

determined fractured zone

The geophysical data described above as well as the rock-core retrieved from MW111B further suggest that bedrock beneath the central portion of the Site may be more accurately characterized

as a series of fractures and faults rather than an area of competent bedrock with one or two

discrete faults

33 Hydrogeology The following sections discuss data collection and evaluation results relative to groundwater flow

directions and rates in overburden deposits and the upper portion of the bedrock unit

331 Hydraulic Conductivity The hydraulic conductivity distributions within the overburden and bedrock formations were

evaluated through the performance of rising and falling head slug tests constant flow tests and

by empirical correlations with measured soil grain size distributions The slug test methodology

and data analysis methods are discussed in Appendix F Because the falling head test results for

shallow wells were influenced to some degree by soil above the water table only rising head test

data were used for the water table wells to compute mean values The constant flow test

methodology is described in Section 283 and Appendix F Table 3-1 summarizes the measured

hydraulic conductivity values from the slug and constant flow tests for wells grouped together

based on lithology and screen depth as follows shallow top-of-till till and bedrock Hydraulic

conductivity estimates based on grain size are listed in Table 3-2 for comparison but only

constant flow and slug-test data were used to calculate mean hydraulic conductivity values for

different portions of the aquifer Laboratory grain size data are presented in Appendix G

5797wpdocraquogalluprifinlaquoltextmastem fill061297 3-9 QST Environmental


The top-of-till wells are considered to be the most representative of the more permeable section of X^^JF

the overburden aquifer characterized by coarser soil grain sizes where a large percentage of the

total groundwater flow occurs Across the Study Area the mean hydraulic conductivity for the

top-of-till wells is 0005 centimeters per second (cms) with values ranging from 0000053 cms

to 0074 cms Northwest of the railroad tracks in the northern portion of the Study Area where

the aquifer thickens the mean hydraulic conductivity for top-of-till wells (MW102TT

MW103TT MW104TT MW117TT and MW118TT) is 0037 cms This value of 0037 cms

which is approximately an order of magnitude larger than the overall Study Area mean for top-ofshy

till wells appears to be most representative of the hydraulic conductivity within the major portion

of the VOC plume By comparison the grain size results are similar in magnitude but somewhat

lower than the Study Area average for the constant-flow and slug tests because they indicate an

average hydraulic conductivity of 0003 cms for the coarse stratified drift samples with values

ranging from 00006 cms to 0006 cms The mean hydraulic conductivity for shallow wells

which are generally screened in finer-grained soils is 0001 cms and varies between 000006

cms and 002 cms The shallow well constant-flow and slug test results are comparable to the

mean grain-size correlation value of 0002 cms for fine stratified drift soil samples

The mean hydraulic conductivity for the till wells (000047 cms) is approximately a factor of ten

less than the mean Study Area top-of-till value and varies between 00002 cms and 0002 cms

The till appears to be hydrogeologically different from the other overburden deposits and on the

average provides increased resistance to groundwater flow This added resistance is not

considered to be significant however because the consistency of the till is highly variable and the

hydraulic conductivity contrast is relatively small

The slug test results for the bedrock wells yield the lowest average hydraulic conductivity

000018 cms The bedrock results though should be considered less accurate than the

overburden estimates due to the highly variable nature of the fractures in the rock matrix and their

associated non-linear effect on computed hydraulic conductivity

332 Groundwater Flow

3321 Surficial (Overburden) Groundwater Flow

The following discussion on overburden groundwater flow is organized according to relative

locations within the Study Area All references to flow direction are inferred based on measured

hydraulic gradients The central portion of the Site in the vicinity of the Former Seepage Bed is

dominated by the presence of a bedrock-controlled topographic high which for the most part is

overlain by unsaturated till Because of this feature overburden groundwater flow patterns can be

effectively treated as separate entities those located to the north of the hill and those located to

the south

5797wpdocraquoglaquolluprifinlaquoltextmasterrifhl061297 3-10 QampT Environmental


Table 3-3 summarizes the water level data collected from monitoring wells and piezometers

during the quarterly monitoring rounds Plates 3-8 and 3-9 depict deep and shallow piezometric head distributions respectively (for November 6 1995) throughout the northern Study Area

Plate 3-9 also shows the piezometric head distribution in the southern Study Area Groundwater

flow maps for other dates are presented in the ISCR (ESE 1995) Water level data for the

monitoring wells at the former Pervel facility were used in both the shallow and deep flow maps

because they are screened in the middle portion of the aquifer As a result these wells are

considered to be hydraulically representative of both portions of the aquifer A saturated

thickness map (Plate 3-10) was created by subtracting the interpolated bedrock surface (Plate 3-6)

from the shallow overburden piezometric surface measured on November 6 1995 which is approximately equal to the groundwater table configuration To facilitate interpretation of flow

patterns calculated two-dimensional groundwater pathlines which represent the mean horizontal trajectory of a parcel of groundwater in the overburden aquifer originating from several locations

in the Study Area are also shown however the pathlines do not account for vertical flow within the aquifer which is important in the shallow portion of the aquifer Data interpolation by the

method of kriging piezometric head contour development and numerical computation of pathlines were performed using the data analysis and visualization software package Tecplot

(Amtec Engineering 1994) The pathlines are based on a steady state velocity field computed

directly from the interpolated head distribution using Darcys law and assume homogeneous

isotropic conditions

Southern Study Area

Overburden groundwater flow south of the Former Seepage Bed is primarily influenced by two factors (1) the slope of the bedrock surface which defines the base of the unconsolidated deposits and (2) regional hydrologic drainage patterns The west-southwest dip of the bedrock

surface strongly influences the general east to west flow of groundwater The average east-west

horizontal hydraulic gradient in the southern portion of the Study Area is approximately 001 feet per foot (feet of vertical head change per foot of horizontal distance)near well MW112S and

piezometer PZ-202 whereas the typical bedrock surface slope in this area is about 01 feet per

foot The configuration of the bedrock surface is important because the slope of the groundwater

table in the overburden would tend to equal the slope of the underlying bedrock in cases where

the saturated thickness is relatively small and the slope is large This process is analogous to flow

in a river where the water surface profile tends to reflect the slope of the river bed under steady-

state conditions In the southern Study Area the water table slope (ie horizontal hydraulic

gradient) is steep but less than the dip of the bedrock surface because the saturated thickness of

the overburden aquifer increases in the direction of flow The saturated thickness increase also

5797wpdocsglaquolluprifinlaquoltextmlaquogterrifiil061297 3-11 QST Environmental


increases the transmissivity of the aquifer (and decreases the resistance to flow) thus causing the

horizontal hydtaulic gradient in the overburden to be less than the bedrock slope The

overburden becomes unsaturated north of PZ203 due to the continued increase of the bedrock

surface elevation in the direction of the Former Seepage Bed The wetlands and stream located a

few hundred feet west of the railroad tracks also affect flow directions and rates because they act

as discharge points for groundwater

Northern Study Area

Due to the increased saturated thickness north-northwest of the Former Primary Disposal Area

groundwater flow conditions in both shallow and deep sections of the aquifer are discussed The

top-of-till wells are considered to be most representative of horizontal flow conditions in all but

the shallow portion of the aquifer Primary reasons for the differences between shallow and deep

flow conditions include (1) the deep aquifer hydraulic conductivity northwest of the railroad

tracks is a factor of about 40 greater than the shallow hydraulic conductivity resulting in the

lower to middle portions of the aquifer controlling regional groundwater movement and (2)

rainwater infiltration and hydraulic influences of Mill Brook cause vertical flow to be important in

certain areas of the shallow aquifer The focus of this section is horizontal groundwater flow in

the middle to lower sections of the aquifer as characterized by Plate 3-8 Shallow flow

conditions (Plate 3-9) are discussed in Section 3323

In the northern portion of the Study Area three hydrogeologically distinct zones exist Between

the Former Primary Disposal Area and the Former Seepage Bed the hydraulic gradient is steep

(approximately 003 feet per foot between wells MW109S and MW110S) and is strongly

influenced by the dip of the bedrock surface (01 feet per foot) As shown on the insert on Plate

3-10 the saturated overburden thickness increases from zero south of well MW109 to about 20 to

30 feet near the former disposal areas North-northwest of the Former Primary Disposal Area the

hydraulic gradient lessens significantly to a range of 00003 to 00007 feet per foot between wells

MW105TT and MW102TT representing a factor of 40 to 100 reduction The most important

factors which produce the flatter gradients in this area are the more than order-of-magnitude

increase in hydraulic conductivity of the coarser-grained deposits and the substantial increase in

the saturated overburden thickness northwest of the railroad tracks North-northeast of Mill

Brook the hydraulic gradient is about 0007 feet per foot near wells MW117TT and MW118TT

Northwest of the railroad tracks groundwater flow in the middle to lower portions of the aquifer

converges from the northeast and southwest toward a centerline area generally defined in the

downgradient direction by wells MW105 and MW102 The flow direction near these wells is

generally to the northwest Northeast of this centerline groundwater flows in a southwesterly



^ ^ direction from the vicinity of Mill Brook and the former Pervel flock plant North of Mill Brook

and west of the railroad tracks the predominant groundwater flow direction becomes more

westerly As discussed in Section 42 and 52 these flow directions are very consistent with the

observed groundwater contaminant distribution


Study Area Figures 3-1 to 3-20 are groundwater elevation hydrographs for each well cluster in

the Study Area representing the period January 1995 to May 1997 (except for wells MW117

MW118 and MW119 which were not installed until November 1995) Groundwater levels were

high in January 1995 May 1996 and February 1997 and decreased by about two feet during July

1995 and August 1996 This variation is consistent with the fact that recharge rates become very

small during the summer months

3322 Bedrock Groundwater Flow

Groundwater flow within fractures in the top ten to 20 feet of the bedrock unit was evaluated

through the performance of the hydraulic conductivity (slug) tests and water level measurements

in monitoring wells A bedrock piezometric head map based on November 6 1995 water levels

is shown on Plate 3-11 along with inferred groundwater pathlines For the pathline development

it was assumed that the hydraulic conductivity distribution is isotropic because potential

influences of fracture orientation on flow direction have not been quantified As expected the

direction of the dip of the bedrock surface has a major influence on the horizontal hydraulic

gradient and flow direction However vertical flow from bedrock to overburden is also

important as discussed in Section 3323

South of the Former Seepage Bed groundwater in bedrock moves primarily in a westerly

direction while in the northern Study Area the predominant flow component is toward the

northwest In both areas the horizontal hydraulic gradient is on the order of 002 feet per foot

The steepest gradients (003 feet per foot) are found in the vicinity of the Former Seepage Bed

and the local high in the bedrock surface just east of MW111 The horizontal hydraulic gradient

reduces to about 001 feet per foot in the southern portion of the Study Area (near wells MW115

MW114 and MW112) and north-northwest of the former disposal areas Groundwater flow in

bedrock near the Former Seepage Bed is toward the northwest in the direction of wells MW113

and MW106 and exhibits no apparent influence from the locally increased fracturing identified

from the geophysical investigation and the hydraulic testing in well MW111B

5797wpdocsgalluprifinaltextm8tem fhl061297 3-13 QST Environmental


3323 Vertical Flow

BedrockDeep Overburden Interface

Vertical groundwater flow is an important component in the upper several feet of the bedrock

unit This observation is supported by the water level hydrographs (Figure 3-1 to 3-20) and data

presented in Table 3-4 which summarizes the vertical hydraulic gradients between pairs of

monitoring wells in various well clusters across the Study Area Data characterizing the hydraulic

interaction between the bedrock and the lower portion of the overburden were evaluated for the

following well pairs MW102B-MW102TT MW105B - MW105T MW107B - MW107T

MW108B - MW108TT MW109B - MW109S MW112B - MW112T MW113B - MW113S and

MW1 15B - MW1 15TT For all measurement dates groundwater was found to be discharging

from bedrock into overburden at each location except for the January 1995 and February and May

1996 measurements at location MW109 At MW109 the saturated overburden thickness is less

than a few feet and MW109 is located at a much higher bedrock elevation relative to all other

locations at which upward vertical flow from bedrock was measured The vertical hydraulic

gradients between bedrock and top-of-till wells are generally more than a factor of ten greater

than the horizontal hydraulic gradients within the VOC plume downgradient from the Former


Overburden

In the overburden aquifer the vertical flow component is significant within shallow deposits in ~

the vicinity of the Former Primary Disposal Area and within the streambed sediments and the

upper portion of the aquifer near Mill Brook Plan view and cross-section maps were developed

to illustrate vertical piezometric head differences Plate 3-12 shows the November 6 1995

vertical piezometric head distribution and general groundwater flow directions along geologic

cross-section B-B Plate 3-13 is a plan view contour map of the shallow minus deep piezometric

head difference in the overburden aquifer As shown by the water level hydrographs the vertical

hydraulic gradients in the aquifer are relatively consistent throughout the observation period

Consistent downward hydraulic gradients have been observed at well clusters MW107 MW108

and MW116 Near the Former Primary Disposal Area water levels in MW107S were two to

three feet higher than the level in MW107TT resulting in a downward vertical hydraulic gradient

that is about a factor of 100 greater than the horizontal gradient from MW107TT to MW105TT

In addition shallow piezometric heads near MW108 and MW1 16 have ranged from 05 to 15

feet higher than heads in the lower portion of the aquifer This downward component at MW107

likely results from the low hydraulic conductivity of shallow soils near the well screen of

MW107S (factor of 200 less than underlying deposits refer to MW107S and MW107TT data in

Table 3-1) and drainage of surface water runoff from upslope areas into the depression formed by

excavation of the Former Primary Disposal Area The low hydraulic conductivity test result for

5797wpdocsgalluprifinlaquoltextmasteiTifhl06 1297 3-14 QST Environmental


MW107S and the observed downward hydraulic gradient may be related to the increased silt

content of soils near well MW107S The vertical VOC distribution at location MW107 (shown

on Plate 3-12 and discussed in Section 4) also strongly supports a predominantly vertical

groundwater flow direction in the upper portion of the aquifer because only trace levels of VOC

were detected in MW107S The downward hydraulic gradients in the vicinity of wells MW108

and MW116 (Plate 3-13) also appear to be associated with the higher hydraulic conductivity of

deep deposits compared to shallow soils (Section 331) and groundwater recharge

West of the railroad tracks near well clusters MW102 MW101 and MW118 the measured flow

direction in the aquifer is predominantly horizontal based on the negligible vertical hydraulic

gradient between shallow and top-of-till wells at these locations However in the immediate

vicinity of Mill Brook vertical groundwater flow is important within the upper several feet of the

aquifer In the vicinity of wells MW103 MW117 and MW119 shallow piezometric heads are

generally 03 to one foot lower than deep heads Using a representative aquifer thickness of 50

feet the average upward vertical hydraulic gradient in this area is about 001 feet per foot by

comparison the local horizontal hydraulic gradient is approximately 0007 feet per foot Based

on these data a significant fraction of the shallow aquifer near wells MW103 MW117 and

MW119 may be discharging into Mill Brook Within the lower portion of the aquifer the

vertical hydraulic gradient becomes very small in magnitude

To further evaluate the hydraulic influence of Mill Brook on the overburden aquifer a vertical

two-dimensional numerical groundwater flow model was developed and a sensitivity analysis was

performed (Appendix U) The results of the modeling indicate that vertical flow in the upper

portion of the stratified drift aquifer near Mill Brook is more important west of the railroad tracks

(eg near wells MW101 and MW102) than east of the tracks (eg near well MW119) This

difference is due to the much smaller horizontal hydraulic gradients (on the order of 00003 feet

per foot) that are present west of the railroad tracks compared to ths area north of Mill Brook and

east of the railroad (horizontal gradients approximately 0007 feet per foot) Because the mean

water level in the brook is lower than the groundwater table elevation vertical flow is created in

the upper portion of the stratified drift aquifer and the depth to which this vertical flow is

important is greater in areas where the horizontal hydraulic gradient (and groundwater velocity is

less) In the vicinity of wells MW101 and MW102 the groundwater flow simulations indicate that

as much as one-third to one-half of the stratified drift aquifer may discharge into Mill Brook

East of the railroad tracks no greater than ten to 25 percent of the groundwater flow in the

stratified drift aquifer is estimated to discharge into the brook

East of the railroad tracks and south of Mill Brook a consistent downward groundwater flow component is observed in addition to the regional horizontal flow component As discussed

5797wpdocraquograquolluprifinaltextmaBterrifhl061297 3-15 QST Environmental


above this downward component is largest near the Former Primary Disposal Area A small

downward flow component was also observed in the vicinity of wells MW106 and MW104

Figure 3-21 is a three-dimensional perspective drawing of groundwater movement in the

overburden aquifer which was developed to further illustrate the relative importance of the

horizontal and vertical flow components in the vicinity of the Former Primary Disposal Area

The figure consists of the two sets of piezometric head contours representing shallow and deep

(top-of-till) water level measurements recorded on February 2 1995 The lower piezometric

surface is representative of flow conditions throughout the middle to lower portions of the aquifer

The upper surface represents the piezometric head variation near the water table Presented

together in the same figure these two sets of contours allow an interpretation of the predominant

(but not all) three-dimensional pathlines originating in the vicinity of the Former Primary Disposal

Area As the pathlines illustrate shallow groundwater near these locations is expected to move

predominantly downward in the upper portion of the aquifer (although some local horizontal flow

may occur due to variations in the hydraulic conductivity of aquifer material) due to the large

vertical hydraulic gradients and the small aquifer thickness

Once groundwater has passed through the less permeable shallow soils it moves in a

predominantly horizontal direction dictated by the piezometric head distribution in the lower

portion of the aquifer

Based on the stream piezometer data presented in Table 3-5 Mill Brook generally gains water

from the overburden aquifer in the northern portion of the Study Area For most dates stream

bed flow was upward at piezometers PZ-6 PZ-5 PZ-4 PZ-4A and PZ-4B located west of the

railroad tracks and at piezometers PZ-1 and PZ-2 located east of the railroad tracks The

streambed vertical flow direction at piezometer PZ-3 located immediately upstream from a beaver

dam and possibly influenced by backwater effects was variable These data are consistent with

the shallow groundwater flow conditions depicted in Plate 3-9 where the head contours passing

through Mill Brook are bent (or V) in an upstream direction This piezometric head contour

pattern is representative of a gaining stream

Any groundwater discharge from the aquifer into Mill Brook would be significantly diluted by

flow in the brook A rough estimate of the potential surface water dilution rate can be obtained

by comparing the stream flow rate with the total discharge rate of groundwater through a given

vertical cross-sectional area For example using an upper bound hydraulic conductivity estimate

of 100 feet per day (0035 cms) a horizontal hydraulic gradient of 0001 feet per foot and an

area 200 feet wide (plume width) by 20 feet deep (about one-third of the aquifer thickness) a

conservatively high estimate of potential discharge from the contaminated portion of the aquifer

5797wpdocraquogalluprifinaltextmasterrifhl061297 3-16 Q^T Environmental


into Mill Brook is approximately 0005 cubic feet per second or cfs (21 gpm) Based on a

measured stream flow rate of about 30 cfs at station UB10 the concentrations of dissolved

constituents in groundwater would be reduced by a factor of about 6000 upon mixing with the

entire stream flow

34 Ecology An ecological study was performed primarily to delineate wetlands and to make local observations

of the types and abundance of plants and animals in the area

341 Wetland Delineation

Delineation of wetlands within the Study Area and adjacent lands was conducted during the period

of August 26 to September 1 1994 Team members included two ESE wetlands biologists and a

certified soil scientist affiliated with the Soil Science Society of Southern New England As

discussed in Section 2131 the delineation performed to meet the States criteria focused on soil

types and hydric soil characteristics while the delineation performed to meet the Federal criteria

used USACOE methods which include the examination of vegetation hydrology and soils

As shown on Plate 3-14 wetlands were identified and delineated along the northern and western

portions of the Study Area Areas bordering the Site to the south and east reflect upland

conditions

Wetland delineation efforts were initiated along the face of a steep gradient along the southwestern

portion of the study area (west of the railroad grade) This allowed the field team to observe the

most obvious characteristics of both upland and wetland regimes Areas reflecting more subtle

wetlandupland indicators were investigated after having gained local experience with the obvious features

The wetland bordering the southwestern portion of the study area is a white cedar swamp

(unnamed) supporting a varying density of trees The swamp is hydraulically connected to the

Mill Brook system by a narrow stream The stream limits surface water flow causing the swamp

to maintain a long hydro period (duration of inundation or saturation) even though it is

topographically higher than the receiving floodplain It appears that the swamp remains inundated

during most years with the possible exception of drought years Judging from the high hydraulic

conductivity of the surrounding soils the swamp receives water through seepage from

surrounding uplands and to a lesser degree from surface water runoff

Portions of the swamp support a low density of older cedars while other areas support denser

stands of young cedars It appeared that the older age class occurred in deeper water while the

5797wpdocsgalluprifinraquoltextmasterrifhl061297 3-17 QST Environmental


younger stands favored shallower water White cedar trees are not tolerant of fire events and it is r

likely that this age class distribution reflects a fire-maintained system where the deeper portions of

the swamp have been more effective in excluding natural fires hence supporting the oldest

cedars Additional hydrophytic plant species identified within the transition zone include red

maple common reed duckweed jewelweed cattail and coast pepper-bush

The upland system bordering the cedar swamp and floodplain forest supports a sub-climax to near

climax hardwood forest Topography of the upland includes steep slopes to gently undulating

land Canopy vegetation (trees) are dominated by oak species (red white and chestnut) with

white oaks nearer the wetland transition area and red and chestnut occurring on the higher

portions of the uplands Other canopy species included white ash quaking aspen hickories and

dogwoods Common understory vegetation included sheep laurel black cherry and green briar

Herbaceous vegetation included species found in the under story and canopy in addition to hay-

scented fern among others

Northward of the stream feature draining the cedar swamp lies the broad floodplain of Mill Brook which closely coincides with the northern boundary of the Site The floodplain is generally flat with many small raised hummocks This area reflects more seasonal fluctuations in hydro period and shallower water depths than the cedar swamp a result of more efficient drainage of the system For this reason natural succession is more advanced and the system supports a higher _ Jgth

diversity of hardwood canopy under story and herbaceous species composition

With the exception of two small isolated topographic depressions (excavated pits) located just west of the southern portion of the Site the delineated wetland areas correspond with the edge of the Mill Brook floodplain Most of the wetlandupland boundary occurs along the edge of a steep grade which closely coincides with the 150-foot ground elevation contour interval The sharp relief produces a narrow transition zone between upland and wetland communities The delineated lines reflect this as the State and USACOE wetland boundaries coincide at nearly

every location The State and USACOE lines are different in a small area adjacent to the railroad tracks immediately north of the Site In this area the State line is upgradient of the USACOE line The soils above the floodplain do not exhibit hydric soil characteristics as defined in the federal manual used for delineating wetlands The soil appears well-drained and depth to water is at a lower elevation than the floodplain soil just a few feet away The soil resembles the description of Suncook an excessively drained soil commonly mapped with Rippowam soils Both Rippowam and Suncook soils are listed on the State hydric soils list while Suncook is not listed by SCS as a hydric soil



A relatively small area of wetlands were determined to occur within the boundaries of the Site proper Wetlands occur in the area northeast (upgradient) of the Former Primary and Secondary

Disposal Areas and along the northern border of the Site east of the railroad bed The two topographic depressions corresponding to the former disposal areas (primary and secondary) lack

hydrophytic vegetation and hydric soil characteristics Other excavated areas to the south and

southwest (on-site) support hydrophytic vegetation and meet hydrology criteria but lack hydric

soil characteristics The depression to the southwest bordering the railroad supports hydrophytic vegetation and is occasionally inundated with surface water (following significant precipitation

events) but lacks hydric soil indicators In this area the ponded water was judged to be the

result of a confining layer of residual tar (presumed to be associated with former CTDOT asphalt

plant operations) immediately beneath an organic layer which causes precipitation to accumulate

342 Plant and Animal Survey

Site Characterization

An objective investigation of native plant and animal species and their habitat was conducted by US Fish and Wildlife Service (USFWS) staff in summer of 1993 (Prior et al 1995) Their

examination included a Site walkover observation and mapping of vegetation cover (shrubs

trees hydrophytic plants) and observation of direct or indirect evidence of wildlife (birds mammals amphibians) Although the Site proper is characterized as highly disturbed no

conclusions were drawn with regard to the effects of past human disturbance on the local ecology

The large majority of plant and animal species observed in the study are native to the region and

commonly found in other disturbed communities andor wetland environs

Reconnaissance of the study Site and adjacent lands was performed prior to delineation activities

to identify habitat types terrain physical access and develop logistics for completing the wetland

delineation The study area is a peninsular feature which extends northward and westward from

the Site entrance at Tarbox Road The study area is bisected diagonally by the railroad right-ofshy

way The Gallup Quarry Site (the quarry) lies to the east of the railroad divide and the remainder

of the study area (the west end) lies to the west Portions of the east boundary of the quarry abut

State Route 12 with other areas bounded by private property

The boundaries of the peninsula are characterized generally by steep slopes which are met

immediately by wetlands The upland soils are glacial till with some areas composed mostly of sands with coarse gravel occurring with lower frequency Some of the higher and relatively

undisturbed areas are composed of large rocks protruding to the ground surface Soils in the

transition zones between upland and wetland are composed of organic muck overlying sand

5797wpdoc8gilluprifinaltextmalaquoterriftil061297 3-19 QST Environmental


These natural conditions along with historical use of portions of the area (mining and

manufacturing) cre responsible for the character of the plant communities found throughout the

study area The quarry reflects significant disturbance from historical mining and asphalt

operations The Site has numerous excavated depressional areas and areas of mounded earth

material These features significantly distinguish the quarried area from the area off-site to the

west which is undeveloped and relatively undisturbed The assemblage of plants in the quarry

reflects these conditions many of the excavated zones are devoid of vegetation and areas adjacent

to them support a mix of successional pioneer species Density of vegetation ranges from bare

soil to dense brush and sapling sized trees Areas of highest vegetation density are associated

with both low elevation (greatest soil moisture regime) and age (length of time since disturbance)

Trees throughout the quarry are young and small in comparison with those found in the forested

areas west of the railroad Vegetation on-site is characterized as early successional species The

more common species include black willow northern bayberry eastern cotton-wood quaking

aspen goldenrod and black cherry

Few wildlife species were observed or noted during wetland delineation activities Wildlife

activity within the Study Area was limited during the survey period but should be expected to

support a much greater diversity of wildlife during the spring and summer seasons when birds

(especially migratory) conduct nesting and rearing activities Most of the species observed during

the survey are expected to overwinter at the study area Bird species recorded include mourning

dove eastern peewee tufted titmouse black-capped chickadee blue jay white-breasted nuthatch

gray catbird American robin and northern cardinal

Vegetation species were recorded during the wetland delineation and are presented in Table 3-6

These reflect species occurring within wetland transition zones Additional species are expected

to occur in more xeric uplands and deeper wetlands

Although no qualitative samples of freshwater macroinvertebrates were obtained the distribution

of different genera between stations would appear to be strongly influenced by the variable

substrate composition and habitat which ranges from shaded moderate flowing rocky stream bed

(eg UB1 UB9) to sunny low energy depositional areas containing sand or deep muck (eg

UBS LB2)



40 Nature and Extent of Contamination

This section discusses the distribution of contaminants within the various media throughout the

Study Area and is based on analytical data collected during nine separate sampling events These nine sampling events include the Phase 1A investigation the Phase IB investigation and the Long-

Term Monitoring Program events conducted during April July November 1995 February May

August and November 1996 and February 1997) The results of the Phase 1A investigation

Phase IB investigation and the Long-Term Monitoring Program sampling events (except

November 1995 which was conducted concurrently with the Phase IB investigation) were also

presented in earlier reports (ESE 1995 -1995b -1995c 1996a 1996b 1996c 1997a 1997b)

Section 41 addresses the results of investigations into potential source areas including surface and subsurface soil Section 42 addresses the results of groundwater investigations Section 43

presents the results of investigations of surface water sediments and wetland soils Section 44 addresses the results of air monitoring investigations Section 45 identifies potential sensitive

human receptors within a one mile radius of the Site

Sample analyses were performed pursuant to the Gallups Quarry Superfund Project RIFS Quality Assurance Project Plan dated August 29 1994 Laboratory analytical testing for Level 4

was generally conducted for analytes identified in the Contract Laboratory Program (CLP) target

compound list (TCL) for organics and target analyte list (TAL) for inorganics Analyses were

conducted pursuant to the CLP Statement of Work for Organics MultimediaMulticoncentrations

Document OLM 018 and the CLP Statement of Work for Inorganics

MultimediaMulticoncentrations Document ILM 030 Appendix IX analyses were conducted by

CLP and SW-846 Methods as described in the QAPP Low-level VOC in drinking water were analyzed by EPA Method 5242 with CLP SOW reporting Laboratory reports for the Phase 1A

Phase IB and Long-Term Monitoring Program sampling events are presented in Appendices H

through P Laboratory data for sample splits collected by EPAs oversight contractor during the

Phase 1A July 1995 and Phase IBNovember 1995 sampling events are also presented in

Appendices H J and K respectively The results of detected analytes are summarized in Section 4 tables The definitions of the qualifiers used for the laboratory data precede the tables in

Section 4 As discussed in various sections analyte concentrations are given either as milligramskilogram (mgkg) or microgramsliter (ugL) The units mgkg are also used

interchangeably with the term part per million (ppm) The units ugL are equivalent to parts per

billion (ppb)

Data validation was performed on all Level 4 data according to the requirements of EPA Region

I Laboratory Data Validation Functional Guidelines for Evaluating Organic Analyses (February 1

5797wpdoclaquogilluprifinaltextmlaquo8terrifiJ061297 4-1 QZT Environmental


1988 as modified November 1 1988) and Inorganic Analyses (June 13 1988 as modified

February 1989) Data validation was performed by David MacLean an independent data

validator Summaries of Mr MacLeans data validation results are presented in Appendix Q

41 Contaminant Source Investigation 411 Visual Site Reconnaissance

A comprehensive visual site reconnaissance was conducted over a three week period from August

23 until September 13 1994 to determine the potential presence of unknown disposal areas

Prior to the start of this survey a grid system was established to allow systematic coverage of the

Site and to locate features of interest The grid used to conduct the visual Site reconnaissance is

described in Section 21 A Site plan which includes the survey grid and the features described

below is shown on Plate 4-1 The features identified on Plate 4-1 are also summarized in Table 4-1

Based on this visual survey the ground surface in the northern portion of the Site which includes the Former Primary and Secondary Disposal Areas is covered with sand and gravel with sparse

to no vegetation Topographic relief is estimated to be as much as 20 to 30 feet and is attributed

to the Sites past usage as a sand and gravel quarry Many of the topographic low spots were

observed to contain either standing water (following rain events) or moist soil (indicative of

intermittent periods of ponded water)

The central portion of the Site which contains the Former Seepage Bed is presently heavily

vegetated Crushed stone and boulders are evident over a large portion of this area and the soils

consist mainly of a sandy till Immediately east and northeast of the Former Seepage Bed is a

topographic high with numerous boulders at the ground surface Evidence of previous test pit

explorations were also observed in this general vicinity Asphalt and mounds of asphalt pavement

were also observed in several areas and are presumed to be remanent of the State of Connecticut

Department of Transportation (CTDOT) asphalt plant operations discussed in Section 132

The southern portion of the Site contains the entrance to the former CTDOT asphalt plant as well

as the remains of the former plant itself These remains consist primarily of concrete footings

and retaining walls The remains of the asphalt plant are located along trending lines E through

K approximately 800 to 900 feet north of Tarbox Road The remains of a 6-foot diameter brick

and concrete masonry structure were observed along with an 8-inch diameter clay pipe leading

into the ground at the former plant location

The area located in the southwestern portion of the Site along line A includes mounded earthen

material piled along the western perimeter of the Site Scattered metal debris including several



empty rusted drums were observed adjacent to and partially buried within the mounded materials

Other objects consisting of timbers steel culvert tires and mounded asphalt were also observed

along the A line Mounded earthen materials located on lines M and N (400 to 650 feet north of

Tarbox Road) were observed to also contain miscellaneous debris (corrugated steel culvert hoses

and cables tires etc) and several empty rusted drums These areas are presently heavily

vegetated Other areas at the southern portion of the Site consist of a mixture of grassland and

brush There are numerous mounds of earthen material and scattered patches of asphalt and

pavement remanent of CTDOT operations throughout this portion of the Site

The Bionetics Corporations under contract to USEPA performed a review of historic aerial

photographs of the site and issued a Site Analysis Report (Bionetics Corp 1990) The historical

aerial photographs were used to prepare a Site plan which indicated the locations of suspected or

potential disposal areas (Figure 4-10 from the Phase 1A Work Plan (ESE 1994)) That Site plan

showed the locations of the three known former disposal areas as well as several much smaller

features described below Based on the visual reconnaissance performed during the RI areas

described in the Bionetics Report as either stained or wet or standing liquid or wet ground

correspond to topographic low spots in which ponded rainwater has been observed In addition

no visual evidence indicative of disposal activities was observed in the vicinity of the several

pits (dated 1981 through 1988) identified in the Bionetics Report These pits are believed to

be remnant of previous investigation test pits

An area described in the Bionetics Report as an extraction and an area of disturbed ground

northwest of the Former Seepage Bed correspond to an excavated area in which asphalt and

miscellaneous debris were observed during the Site reconnaissance The presence of mounded

materials in the vicinity of the Former Seepage Bed was confirmed during this visual

reconnaissance The mounded materials observed are comprised of earthen materials andor

asphalt pavement

A number of areas located within the southern portion of the Site were described in the Bionetics

Report as suspected disposal areas Features described as containing liquid generally

correspond to topographic low spots which were observed during the Site reconnaissance to

contain ponded rainwater following rain events The large feature described in the Bionetics

Report as extraction with liquid and associated dark toned material corresponds to a presently

open excavation in which asphalt was observed No features or specific objects were observed

during the Site reconnaissance which correspond to the locations of the unidentified objects

noted in the report The remains of a circular foundation observed during the Site reconnaissance

in the vicinity of the former CTDOT plant corresponds to the location of the possible vertical

5797wpdocraquogalluprifiiwltextmasterrifhl061297 4-3 QST Environmental


tank Scattered mounds of earthen materials observed throughout the southern portion of the

Site correspond to the numerous mounded materials identified in the Report

Based on the observations made during this survey it is apparent that the landforms on-site have

been altered numerous times during past usage Extensive areas are presently heavily overgrown

and do not appear stressed Various earthen materials have been excavated and mounded at

numerous locations throughout the property and are presumed to be remnant of the former sand

and gravel quarrying operation andor the operation of the State DOT asphalt plant Also

patches of asphalt and mounds of asphalt pavement ranging from several to tens of square feet in

size were observed at multiple areas around the Site

The major features described as potential or suspected disposal areas in the Bionetics Report were

identified and described during the visual reconnaissance Although several empty 55 gallon

drums in various states of decomposition and scattered debris (consisting mainly of residential

trash scrap metal car parts etc) were observed at a number of locations across the Site no

intact drums or significantly stained or stressed areas were observed Other than the three known

former disposal areas no features were observed during the visual reconnaissance which indicate

the potential presence of large disposal or dumping areas

The above mentioned areas which contain debris including several empty 55-gallon drums were

further assessed during the soil gas and geophysical screening surveys performed as part of the

Phase 1A investigation The findings of these screening surveys are discussed below

412 Soil Vapor Survey

The soil vapor survey conducted on-site included a total of 100 soil vapor points installed along

an approximate 100-foot orthogonal grid Six additional sampling points were installed at three

locations where partially buried decomposed or empty 55-gallon drums were observed during

the visual site reconnaissance and at three areas where geophysical surveys detected the presence

of EM-31 andor MAG anomalies Each soil gas sample was analyzed for the presence of the

following eight VOC using a portable gas chromatograph acetone benzene 12-dichloroethene

(DCE) methylethyl ketone (MEK) methyl-isobutyl ketone (MIBK) 111-trichloroethane (TCA)

trichloroethene (TCE) and toluene

Of the 106 soil vapor sampling points tested detectable concentrations of VOC were identified at

only three locations These three locations SV160 SV165 and SV172 (shown on Plate 2-5)

were all located within approximately 50 feet of the Former Primary Disposal Area Specifically

TCE was detected at SV160 and SV165 and TCA was detected at SV165 and SV172



Likewise no VOC were detected at three additional survey points SV201 SV205 and SV206

installed within one foot of the 55-gallon drum which was observed at each of those locations or

at survey points SV202 SV203 and SV204 located in the vicinity of geophysical anomalies

identified during the EM-31 and MAG surveys

As described in the Work Plan the soil gas investigation was used as a screening survey to

identify apparent soil contamination in an effort to locate any potential unknown disposal areas

Based on the results of the soil gas survey no additional potential disposal areas were identified

413 Geophysical Investigations and Test Pits

Electromagnetic terrain conductivity (EM-31) and magnetometer surveys were conducted by

Weston Geophysical of Northboro Massachusetts as screening surveys to identify potential

unknown disposal areas The Weston Geophysical Report (provided as Appendix A) describes

in detail the findings of the geophysical investigations The significant findings of these two

screening surveys and of the follow-up test pit program are discussed below

4131 EM-31 Survey

The electromagnetic terrain conductivity measured across the Site was generally uniform with

most anomalies being attributed to wholly exposed or partially buried metallic debris (eg

automobile body parts empty rusted drums scrap pipe angle iron steel culvert and steel cable)

However two EM-31 anomalies could not be accounted for by noted surface features As shown

on Plate 2-14 the two unexplained EM-31 anomalies were located along trend line M at station

550 and at station 590 Due to the complexity of the anomaly located at station 550 an estimate

of its ferrous mass could not be made The second EM-31 anomaly was described as limited in

extent and was estimated to contain approximately 100 pounds of ferrous material assuming a burial depth of five feet (smaller objects at shallower depths would also explain the anomaly)

4132 Magnetometer Survey

The magnetometer survey identified a relatively flat gradient across the Site with a number of

localized anomalies most of which corresponded directly with visible surface features or objects

(as described above) A total of four anomalies were identified which could not be readily

attributed to known surface features Two of these anomalies occurred along trend line M and

correspond to the two EM-31 anomalies described above A third magnetometer anomaly was

identified along trend line C between stations 760 and 800 This anomaly was described as

approximately 10 feet in width and was interpreted as being the result of small amounts of ferrous

material spread over the length of the anomaly (approximately 40 feet) A fourth anomaly was

identified along line L at station 315 This anomaly was interpreted to consist of a small

amount of ferrous material buried at shallow depth

5797wpdocsgalluprifinaltextmraquosterrifhl061297 4-5 QST Environmental


4133 Test Pit Investigations

As described above the geophysical screening surveys revealed a total of four locations at which

EM-31 or magnetometer (or both) anomalies were detected that could not be attributed to visible

surface features The anomalies measured along line M were noted in both the EM-31 and

magnetometer surveys while the anomalies along lines C and L were only measured in the

magnetometer survey To confirm the source of these anomalies test pits were excavated at the

location of each anomaly Test pit excavation was observed by EPA oversight personnel

The presence of varying amounts of miscellaneous buried scrap metal debris described below

was identified at each test pit location At the anomaly located along Line C the excavated

debris included small rusted cans sheet metal and steel cable During the excavation of the test

pit located at the anomaly along line L a three foot long piece of a solid iron rod

approximately one inch in diameter was found buried approximately four inches below the ground

surface At the anomalies located along Line M a variety of ferrous debris was uncovered

including a crushed eight foot section of corrugated steel culvert approximately 2 feet in

diameter sheet metal nuts bolts steel cable and small rusted cans No drums intact or

otherwise were encountered at any location Soil removed from each excavation as well as the

side walls and bottoms of the excavations were screened for the presence of VOC using a PID

No elevated PID readings were measured Furthermore no visible evidence of staining was

noted in the soil at any of the excavations Upon excavation all metallic debris was placed on

the ground surface adjacent to the excavation and the test pits were backfilled with native soil

Test pit logs for the four test pits are shown in Appendix E

414 Background Soils

Soil samples were collected at two monitoring well cluster locations MW109 and MW112 to

determine the general Site background levels of TALTCL compounds The two locations were

chosen based on their upgradient position in relation to the former disposal areas The soils were

submitted for laboratory analysis for TALTCL parameters (VOC SVOC pesticides PCS

metals and cyanide) Tables 4-2 and 4-3 show the positive detections for VOC and metals

These tables only show the constituents that were detected at the site Constituents that were not

detected in any sample are not shown There were no detections of SVOC or pesticidesPCB in

any background soil sample

Due to the limited surficial deposits and abundance of boulders encountered at the MW109

location samples could only be collected from the 6-8 foot interval which is representative of till

at this location Discrete samples collected at the MW112 location were obtained from the 8-10

foot and 40-42 foot intervals which represent stratified drift and till respectively Composite

5797wpdocsglluprifinlaquoltextmlaquosterrifhl061297 4-6 QST Environmental


samples from MW112 were collected from the 7-14 foot and 34-40 foot intervals (stratified drift

and till respectively) These depths were chosen based on their lithology

The results of the laboratory analyses for the soils collected at MW109 indicate the presence of

trace concentrations (0004 mgkg) of toluene no other VOC were detected No detectable

concentrations of SVOC pesticides or PCB were encountered in soil from the MW109 sample

location

Soils collected at the MW112 location also contained detectable concentrations of toluene

Toluene was detected at concentrations of 003 0017 0029 and 0032 mgkg from 8-10 feet 7shy

14 feet 10-14 feet and 34-40 feet respectively Trace concentrations of methylene chloride

(0003 mgkg) and trichloroethene (0002 mgkg) were also detected in the MW112 sample at 10shy

14 feet and 40-42 feet respectively No detectable concentrations of SVOC pesticides or PCB

were identified at the MW112 location

Although the source of the VOC is unknown all three of these compounds are organic solvents

that are (or were ) commonly used in many household (eg spot removers paint strippers

aerosols) commercial (eg pesticide formulations inks and dyes) and industrial (eg

degreasers) products

Metals concentrations in background soil boring samples are shown on Table 4-3 As expected

various metals were detected in all soil samples Analytical results for metals for all of the

MW112 samples were within the common range for soils found in the eastern United States

Heavy metals were generally detected only at trace concentrations Alkaline earth metals (eg

Ca Mg K) were detected at levels not unexpected for soils in the region Background concentrations of metals in subsurface soils were used for comparison purposes in analyzing the

significance of the metals concentrations measured in other non-background soil samples

415 Soils From Former Known Disposal Areas

Soil borings were drilled at each former known disposal area to determine whether residual

contamination remains in surface and subsurface soils During the Phase 1A investigation a total

of ten soil borings were performed Soil samples were collected from these borings and

submitted for laboratory analysis for TALTCL parameters (VOC SVOC pesticides PCB

metals) pH total organic carbon (TOC) and moisture content An additional six borings were

performed during the Phase IB Investigation Soil samples collected during the Phase IB

Investigation were submitted for laboratory analysis for VOC and pesticidesPCBs The

locations of the soil borings are shown on Plate 2-3

5797wpdoc8galluprifinaltextma8terrifhl061297 4-7 QST Environmental


Samples from the 0-1 foot interval were collected from each boring by hand using a stainless

steel scoop Continuous soil samples beneath the 0-1 foot interval were collected using a truck-

mounted drill rig equipped with standard split-spoon samplers Generally samples were collected

from both above and below the water table and at depth within each of the former known

disposal areas In addition each significant lithologic unit was sampled The specific sampling

depths and length cf sampling interval varied for different analytical parameters depending on the

lithology and volume of sample recovered from each spoon Sample intervals and analytes are

summarized in Table 2-2

A brief description of the reported historical disposal activities and the findings of the Soil

Sampling Program for each specific area are described below Positive hit tables showing the

laboratory results for soil boring samples collected from within the former known disposal areas

are presented in Tables 4-4 through 4-7 The unvalidated laboratory data for TALTCL

parameters are presented in Appendix H (Phase 1A data) and K (Phase IB data) Laboratory

results for pH total organic carbon and moisture content are presented in Appendix R

4151 Former Seepage Bed

The Former Seepage Bed is located near the center of the Site This feature is located on the

north side of a local bedrock high which is overlain by 10 to 20 feet of boundary till Historical

records indicate that this area was used for the direct discharge of liquid waste to the ground

surface It has been reported that an inverted dump truck body was buried in this area and was

connected to the ground surface via a pipe Liquid wastes were then reportedly poured directly

into the pipe The wastes reportedly dumped in this area have been described as low pH liquids

characteristic of metal pickling liquors The dump truck body and the contaminated earth were

removed in 1979 during CTDEP remedial efforts Approximately 20 tons of lime (which is

approximately equal to 10 cubic yards) was reportedly spread in the vicinity of the seepage bed to

neutralize any residual low pH material The soil boring program indicated that fill material in

this area extends from 3 to 7 feet below the ground surface Based on the approximate lateral

extent of this former disposal feature (as shown in historic plans of the Site) approximately 230

yards of sand and gravel fill material were used to backfill the CTDEP excavation

To investigate this area three soil borings (SB101 SB102 and SB103) were completed The

borings within the Former Seepage Bed were terminated at auger refusal depths of 68 feet

(SB101) 185 feet (SB102) and 160 feet (SB103) Within this area groundwater was only

encountered in the bottom 6 inches of the deepest boring (SB 102)

5797wpdocsgalluprifinaltextmasteiTifnl061297 4-8 QST Environmental


Surface Soil Sample Results - Former Seepage Bed

As shown in Table 2-2 the 0-1 foot interval was sampled at each location and submitted for

laboratory analysis for VOC SVOC pesticides PCB and metals No VOC were detected in this

interval at any of the three soil borings within the Former Seepage Bed In the 0-1 foot interval

very low levels of SVOC primarily polynuclear aromatic hydrocarbons (PAH) were detected at

SB101 and SB103 The concentrations of PAH ranged from 0012 ppm to 0076 ppm Moderate

concentrations of bis(2-ethylhexyl)phthlate (15 ppm) were also seen in this interval at SB101

Trace levels of certain pesticides were also seen in the 0-1 foot interval at SB101 [44-DDE

(00014 ppm) 44-DDT (0019 ppm) and 44-DDD (0041 ppm)] and at SB102 [44-DDD

(0011 ppm)] At SB102 a low level of PCB (Aroclor-1260 at 0027 ppm) was detected in the

surface soil sample

The results of metals analyses have been compared to background soils metal concentrations

determined from soil samples collected from the background monitoring wells MW109 and

MW112 With the exception of calcium (12200 ppm) and magnesium (9620 ppm) seen in the

0-1 foot interval at SB102 most metals in the surface soil samples were close to the background

concentrations seen at the Site The elevated concentrations of both calcium and magnesium are

attributed to the 20 tons of lime which were used in this area by CTDEP Compared to the

background level seen for lead (35 ppm) the concentration of this metal in the 0-1 foot interval

was slightly higher at SB101 (59 ppm) SB102 (43 ppm) and SB103 (69 ppm) Also silver

which was not seen in any of the background samples was detected in the 0-1 foot interval at

SB101 at 87 ppm

Unsaturated Zone Sampling Results - Former Seepage Bed

Within the unsaturated zone below the 0-1 foot interval described above only trace levels of

VOC were detected Toluene was seen in SB101 (4-6 feet) and SB102 (16-18 feet) at a

concentration of 0002 ppm Xylene (total) was also detected at the same two intervals at the

same concentrations The only other VOC detected was TCE in SB101 (4-6 feet) at a

concentration of 0004 ppm

The only SVOC detected within the unsaturated zone at the Former Seepage Bed was di-n-octyl

phthlate detected in all three borings at various depths at concentrations ranging from 001 to

0021 ppm Very low concentrations of several pesticides (SB101) and PCB (SB101 and SB102)

were detected at various depths in unsaturated zone samples below the 0-1 foot interval The

pesticides 44-DDD (0033 ppm) 44-DDT (0024 ppm) and dieldrin (000064 ppm) were

5797wpdocBgalluprifinaltextmlaquosteiTifhl061297 4-9 QST Environmental


detected at SB 101 The highest detections of the PCS for Aroclor-1260 and Aroclor-1254 were

0027 (SB102 0-1 feet) and 0034 ppm (SB1012-5 feet) respectively

Within the unsaturated zone below the 0-1 foot interval the only metals detected above the

highest background concentrations were aluminum barium iron magnesium manganese and

potassium The highest concentration of each of these metals was only slightly higher than

background levels and all were within the same order of magnitude

Among the Former Seepage Bed borings only one (SB 102) encountered groundwater above the

auger refusal depth Since only six inches of saturated soil was encountered the limited sample

volume was submitted for VOC analysis only No VOC were detected in this sample

pH TOC Moisture Content - Former Seepage Bed

The pH of samples collected in this area ranged from 622 to 792 Total organic carbon values

(mgkg) ranged from 1600 to 23000 Moisture contents ranged from 42 to 105 percent

4152 Former Secondary Disposal Area

The Former Secondary Disposal Area is located in the northwestern corner of the Site adjacent to

the railroad tracks The Disposal Area is presently seen as a depression which is approximately

50 feet wide by 60 feet long and is approximately 6 to 8 feet below the surrounding ground

surface The ground surface at this area is covered by approximately 2 feet of backfill (mostly

sand) material The fill is underlain by fine- to coarse-grained sand which ranges in thickness

from approximately 6 to 22 feet Sandy till ranging in thickness from 10 to 20 feet underlies the

sand The depth to groundwater from the bottom of the depression is approximately 10 feet

Historical records indicate that this area was used for the disposal of drummed liquid wastes

Approximately 200 drums and an unknown quantity of contaminated soil were removed in 1979

during CTDEP remediation efforts

In order to characterize residual contamination which may be present beneath this area three soil

borings (SB 104 SB 105 and SB 106) were performed within the depressed area ranging in depth

from 30 feet (SB 105) to 36 feet (SB 104) Within this area groundwater was encountered at

approximately 10 feet below the ground surface

5797wpdocsglaquolluprifinlaquoltextmaBterrifnl061297 4-10 QST Environmental


Surface Soil Sample Results - Former Secondary Disposal Area

Within the 0-1 foot interval only a trace concentration of one VOC (ethyl benzene at 00006

ppm) was detected (at SB104) The only SVOC detected in this interval was butylbenzylphthlate

(014 ppm) at SB 104 Very low concentrations of pesticidesPCB were measured at each boring

Aroclor-1254 was detected at SB104 (0025 ppm) and SB105 (0021 ppm) Aroclor-1260 was

detected at all three borings ranging in concentration from 00089 to 0031 ppm Dieldrin was

detected at SB 104 at trace levels (000048 ppm)

In the 0-1 foot interval nearly every metal detected occurred at concentrations close to those for

the background samples with the exception of lead which was detected at a concentration of 118

ppm at SB 104 Cyanide was detected in this interval at very low concentrations ranging from 16

to 97 ppm

Unsaturated Zone Sample Results - Former Secondary Disposal Area

Between the 0-1 foot interval and the groundwater table at the Former Secondary Disposal Area

no VOC were detected The only SVOC detected in this zone were at very low levels

(butylbenzylphthlate at 0037 ppm and di-n-octylphthlate at 0012 to 0029 ppm) Also in this

interval at SB104 and SB105 low levels of the PCB Aroclor-1254 and -1260 were detected at

concentrations up to 0055 ppm and 0018 ppm respectively Dieldrin was detected at a trace

level (00014 ppm) at SB104 Within this zone most of the metals were close to the background

soil concentrations except for lead (224 ppm) at SB104 and copper (476 ppm) at SB105

Cyanide was detected in the 1-10 foot interval at SB104 and SB105 at very low concentrations of

83 and 31 ppm respectively

Saturated Zone Sample Results - Former Secondary Disposal Area

Beneath the groundwater table within the Former Secondary Disposal Area no VOC were

detected The only SVOC detected was di-n-octylphthalate which ranged in concentration from

002 to 008 ppm Very low levels of endrin (00004 ppm) and Aroclor-1248 (001 ppm) were

also detected just below the water table but were not present in the deepest sample collected (26shy

28 feet) The only metals which were detected below the water table at concentrations notably

higher than background levels were copper and nickel Copper ranged in concentration from 621

to 863 ppm while nickel ranged from 119 to 169 ppm The highest concentrations of these

two metals were detected just below the groundwater table



pH TOC Moisture Content - Former Secondary Disposal Area

The soil pH ranged from 688 to 751 TOC ranged from lt 1500 to 2800 mgkg and moisture

content ranged from 37 to 124 percent

4153 Former Primary Disposal Area

The Former Primary Disposal Area is located at the northern end of the Site approximately 150 feet east of the Former Secondary Disposal Area This feature is seen as a circular depression

approximately 130 feet in diameter (at the top edge) and is approximately 8 to 10 feet lower than

the surrounding ground surface Non-native fill material (sand and gravel) ranged in thickness

from approximately 2 to 4 feet Underlying the fill is an approximately 15- to 20- foot thick

generally sandy horizon which overlies 6 to 15 feet of till The water table in this area ranges

from approximately 3 to 6 feet beneath the ground surface in the bottom of the depression

Records indicate that approximately 1400 drums and approximately 5000 gallons of free liquids

were removed from the Former Primary Disposal Area during CTDEP cleanup efforts

Approximately 2000 to 3000 cubic yards of contaminated soil were also removed during that

effort

During the Phase 1A (1994) investigation a total of four soil borings (SB107-SB110) were

completed within the Former Primary Disposal Area to characterize the extent of residual soil

contamination These borings ranged in depth from 24 feet at SB108 to 39 feet at SB109 An

additional six borings (SB111-SB116) were completed during the Phase IB (1995) investigation

Samples collected during the Phase IB investigation were submitted for laboratory analysis for

VOC and PCBPesticides The purpose of the additional borings was to further delineate the

lateral extent of residual VOC and PCB contamination in the unsaturated portion of the soil The

Phase IB borings were terminated just below the groundwater surface typically five to seven feet

below the ground surface The locations of all of the borings are shown on Plate 2-5 however a

detailed close-up showing the boring locations within the Former Primary Disposal Area is shown

as an insert on Plates 4-2 and 4-3 which are discussed below The tabulated laboratory data for

both the Phase 1A and Phase IB soil borings are shown on Tables 4-4 through 4-7 (VOC SVOC

pesticidesPCB and metals respectively)

Surface Soil Sample Results - Former Primary Disposal Area

In the 0-1 foot interval only a limited number of VOC were detected generally at very low

concentrations (Table 4-4) The compounds detected in the 0-1 foot interval (followed by

concentration [ppm] and location) are as follows acetone (0007 ppm at SB107)

5797wpdocsgalluprifinaltextmasterri fhl061297 4-12 QST Environmental

Catlaps Quarry Superfund Project - Remedial Investigation

tetrachloroethene (PCE) (0018 ppm at SB109 and 0002 at SB113) toluene (0005 at SB112

0003 at SB1H and 0002 at SB115) ethyl benzene (0002 at SB113) and total xylenes (0010 at

SB113) In this same interval several phthalates (butylbenzyl bis(2-ethylhexyl) diethyl and dishy

n-octyl) were detected at various locations (Table 4-5) with no apparent spatial trend at

concentrations ranging from 0008 to 17 ppm Several PAH compounds were also detected at

SB110 in the 0-1 foot interval at concentrations ranging from 0007 to 0017 ppm As shown in

Table 4-6 Aroclor 1254 was detected in the 0-1 foot interval at every boring at concentrations

ranging from 0046 to 43 ppm Aroclor-1260 was also detected in the 0-1 foot interval at

concentrations ranging from 0046 to 23 ppm Trace concentrations of several pesticides were

also detected in the 0-1 foot interval in some borings as follows heptachlor epoxide (000058 to

0052 ppm) dieldrin (000059 to 0043 ppm) 44-DDE (000089 to 0081 ppm) and 44-DDT

(000048 to 0027 ppm) Aluminum (12200 ppm at SB110) was the only metal in the 0-1 foot

interval that was detected at concentrations significantly greater than background levels (Table 4shy

7) Cyanide was detected at a very low concentration of 16 ppm at both SB109 and SB110

Unsaturated Zone Soil Sample Results - Former Primary Disposal Area

Beneath the 0-1 foot interval but above the water table a small number of VOC were detected at

various concentrations and locations (Table 4-4) Within this zone no VOC were detected at

SB107 At SB108 methylene chloride was detected at 0001 ppm Ethyl benzene was detected

at SB 109 (015 ppm) SB110 (54 ppm) SB111 (0048 ppm) and SB115 (16 ppm) Total

xylenes were seen at SB109 (16 ppm) SB110 (46 ppm) SB111 (064 ppm) and SB115 (80

ppm) Toluene was detected at SB 110 through SB 115 at concentrations ranging from 0003 to 12

ppm PCE was seen at SB109 SB111 SB114 and SB116 at concentrations which ranged from

0003 to 17 ppm and at SB115 at 28 ppm 111-TCA was detected at SB111 112 114 115

and 116 from 0001 to 14 ppm TCE was also seen at SB111 114 115 and 116 at

concentrations ranging from 0002 to 17 ppm 2-butanone (MEK) was detected at SB111 at

0005 ppm 12-DCE was seen at both SB115 (016 ppm) and SB116 (0009 ppm) Finally 11shy

DCA (0008 ppm) 11 -DCE (0009 ppm) and carbon disulfide (0022 ppm) were all seen at

SB115 Methylene chloride (0001 ppm) was detected at SB108 These detections occurred in

the transition zone between fill and native deposits

The SVOC detected in this zone (shown on Table 4-5) included several phthalates at

concentrations ranging from 0039 to 46 ppm Napthalene was also detected at SB109 (047

ppm) and SB110 (63 ppm) 12-dichlorobenzene and 2-methylnapthalene were detected at SB110

at 098 and 081 ppm respectively The most frequent occurrence and highest concentrations of

phthlates (and SVOC in general) occurred at SB 109 and SB 110

5797wpdocraquogalluprifinaltextmlaquolaquoterrifhl061297 4-13 QST Environmental


As shown on Table 4-6 Aroclor-1254 occurred at most of the borings in this zone at gtbullraquo

concentrations ranging from 00023 to 64 ppm Aroclor-1242 (0043 to 017 ppm) and Aroclorshy

1260 (043 to 24 ppm) were detected at SB109 and SB110 Pesticides were also detected at trace

to very low concentrations at several locations These compounds include dieldrin (000028 shy

00046 ppm) 44-DDE (000043 - 00063 ppm) 44-DDT (00013 - 00081 ppm) beta BHC

(00013-00021 ppm) and delta BHC (000086-00024 ppm) endrin ketone (00028 ppm)

heptachlor epoxide (0008 ppm) heptachlor (00093 ppm) endosulfan I (0008 ppm) and

methoxychlor (0140 ppm) Table 4-7 shows that the only metals detected within this zone at

concentrations significantly higher than background levels were cadmium (131 ppm) and copper

(103 ppm) both of which occurred at SB109 Cyanide was detected in SB110 in the 1-35 foot

interval at a very low concentration of 32 ppm

Saturated Zone Soil Sample Results - Former Primary Disposal Area

The highest concentrations of VOC within the Former Primary Disposal Area occurred just below

the surface of the groundwater table in the natural deposits immediately underlying fill material

As shown on Table 4-4 in the 4-6 foot interval at SB 109 the following VOC were detected 12shy

DCE (059 ppm) PCE (36 ppm) TCA (98 ppm) TCE (62 ppm) ethyl benzene (85 ppm)

toluene (44 ppm) and xylenes (46 ppm) In the next deepest interval sampled (14-16 feet)

generally the same compounds were detected however the concentrations were lower by an

order of magnitude At the last sampled interval (30-32 feet) generally the same compounds

were again detected but at trace levels (0001-0006 ppm) Cyanide was detected in SB110 in the

10-16 foot interval at a very low concentration of 11 ppm

A total of six SVOC were detected just below the water table at a depth of 4-8 feet below ground

surface (Table 4-5) phthalates (0039 to 0058 ppm) napthalene (021 ppm) 2-methylnapthalene

(0034 ppm) phenol (016 ppm) and 124-trichlorobenzene (0046 ppm) SVOC at greater

depths were napthalene (0076 ppm) in the 10-16 foot interval and bis(2-ethylhexyl)phthlate (11

ppm) at the 22-32 foot interval Aroclor-1254 was detected at concentrations which decreased

with depth from 02 ppm at 4-8 feet to 00096 ppm at 23-34 feet

In the saturated zone no metals were detected at levels significantly greater than background

pH TOG Moisture Content - Former Primary Disposal Area

Values for soil pH ranged from 609 to 745 TOC ranged from lt 1500 to 5500 mgkg and

moisture content ranged from 49 to 282 percent


Gallups Quarry Superfand Project - Remedial Investigation

416 Contaminant Source Investigations Summary

The previous discussions regarding the contaminant source investigations are grouped into two

categories

bull surveys to identify unknown disposal areas (if any) and

bull investigations at known former disposal areas

Based on the findings of the Visual Site Reconnaissance the Soil Vapor Survey and the

Geophysical Investigations (including the subsequent confirmatory Test Pits) it is apparent that

significant unknown hazardous materials disposal features do not exist at the Site

Based on investigations performed within the known former disposal areas it is evident that the

Former Seepage Bed and the Former Secondary Disposal Area contain generally trace levels of

VOC SVOC pesticides PCB compounds and cyanide For the most part soil metal

concentrations are comparable to background levels measured at upgradient locations at the Site

although very low levels of cyanide (ranging from 11 - 97 mgkg) were also detected at various

depths within the Former Primary and Secondary Disposal Areas Elevated levels of calcium and

magnesium detected at the Former Seepage Bed can be attributed to the large amount of lime

which was reportedly used during remedial efforts Although elevated concentrations of several

other metals were detected at a few locations these levels appear to fall within regional range

values (for the metals with published ranges)

The Former Primary Disposal Area appears to be the only area with notable levels of residual

contamination primarily VOC including ethyl benzene toluene xylene TCA TCE and PCE

In general the highest VOC concentrations are located at or just below the groundwater table in

native materials immediately beneath the fill materials These concentrations diminish quickly

with depth Toluene ethyl benzene xylene and in one case a low level of PCE were also

detected at or near the ground surface within the fill material Empty gasoline cans numerous

off-road vehicle tire tracks and the remains of large campfire pits have been observed in the

vicinity of the former disposal areas Of the VOC detected the ones considered most significant

are those which are also seen in groundwater above their respective MCL (groundwater results

are discussed separately in section 42) In an effort to illustrate the locations where the more

notable amounts of residual VOC contamination are found Plate 4-2 which shows the locations

of total chlorinated VOC has been prepared On this plate the values for total chlorinated VOC

have been color-coded as follows sample intervals where all compounds were below the detection

limit (BDL) are not colored intervals where total chlorinated VOC values are present but less

5797wpdoc8glaquolluprifinraquoltextmasterrifhl061297 4-15 QST Environmental


than 1 ppm are shown in green values between 1 and 10 ppm are shown in yellow and locations

between 10 and 35 ppm are shown in red The highest value for any interval is 31277 ppm

As indicated on Plate 4-2 total chlorinated VOC concentrations were either BDL or less than 1

ppm for the majority of intervals sampled Total concentrations between 1 and 10 ppm (ie

yellow zones on Plate 4-2) were detected at two locations SB108 and SB109 Total chlorinated

VOC concentrations in the 4-6 interval at SB108 were 155 ppm At SB109 total chlorinated

VOC concentrations were between 1 and 10 ppm within the 2-4 foot interval (17 ppm) and the

14-16 foot interval (213 ppm) Total chlorinated VOC concentrations exceeded 10 ppm at two

locations SB 109 (2019 ppm in the 4-6 foot interval) and SB115 (31277 ppm in the 3-5 foot

interval) As seen on the plan view insert on Plate 4-2 SB109 and SB115 are located within

approximately 25 feet of each other in the northwestern quadrant of the Former Primary Disposal

Area The zone of highest chlorinated VOC contamination appears to be located just beneath the

fill horizon in close proximity to the groundwater surface

Trace to low-levels of PCB were also detected in both near surface samples and (at one location)

at a depth of 32 feet below the ground surface The highest concentration of any single PCB

compound was 64 parts per million in the 1-35 foot interval at SB110 Other detections

included 43 ppm (SB107 0-1 foot interval) 3 ppb (0-1 foot interval at SB109 and SB110) 28

ppm (0-1 foot interval at SB113) 23 ppm (0-1 foot interval at SB107) and 24 ppm (1-35 foot

interval at SB110) All other detections were below 15 ppm

Plate 4-3 has been prepared to illustrate the distribution of PCB compounds detected within the

Former Primary Disposal Area Plate 4-3 shows the concentration and locations for total PCB

compounds for all intervals sampled with the area

Total PCB concentrations have been grouped and color coded on Plate 4-3 as follows sample

intervals where no PCB were detected (BDL) are shown as colorless zones where total PCB were

detected at concentrations less than 1 ppm are shown in green Intervals containing between 1

and 5 ppm total PCB are yellow and intervals between 5 and 10 ppm are shown in red (the

highest value for total PCB compounds anywhere was 88 ppm)

As shown on Plate 4-3 total PCB values at the majority of locations within the Former Primary

Disposal Area are less than 1 ppm Values between 1 and 5 ppm (shown in yellow) were

detected at SB109 SB110 and SB113 These intervals all occur within four feet of the ground

surface and all are within the fill horizon The only intervals where total PCB concentrations are

between 5 and 10 ppm are the 0-1 foot interval at SB107 (66 ppm) and the 1 to 35 foot interval

5797wpdoc8galluprifinaltextmastemfhl061297 4-16 QST Environmental


at SB 110 (88 ppm) There does not seem to be any spatial trend or relationship among these

detections as the detections are scattered among all quadrants of the disposal area

42 Groundwater Quality 421 Temporary Well Point Investigation

The results of the temporary well point investigation discussed in Section 24 indicated the

presence of a narrow groundwater plume (approximately 250 feet in width) of volatile organic

compounds (VOC) originating at the Former Primary Disposal Area and extending about 700 feet

in a northwesterly direction VOC were detected up to Mill Brook and at trace levels at one

location near the northern bank of the brook Plate 4-4 summarizes the VOC detections at

different locations and depths in the aquifer A summary of these field and laboratory data is

presented on Table 4-8 and Table 4-9 respectively The area extent of this VOC plume is in

excellent agreement with the groundwater flow directions measured in the northern Study Area (as

discussed in Section 422) The primary chlorinated VOC detected were 111-trichloroethane

(TCA) trichloroethene (TCE) and 12-dichloroethene (DCE) VOC concentrations within the

Former Primary Disposal Area were found to decrease significantly with depth indicating that the

source material is probably located near or above the water table Further downgradient VOC

were detected at generally lower concentrations and were present throughout the entire aquifer

thickness with no apparent depth-dependent trend Various contaminant transport mechanisms

are discussed in Section 50

In the southern portion of the Study Area low-level detections of methyl isobutyl ketone (MIBK)

were detected in samples from two microwells Also acetone and methylethyl ketone (MEK)

were detected at one location adjacent to Tarbox Road No other VOC were detected at any

location

Due to variability in the results of field VOC analyses (using a portable gas chromatograph) and

off-site laboratory analyses it was determined that the field GC results should not be relied upon

as the only source of information to evaluate either the VOC plume boundary or absolute levels of

particular constituents within the plume Rather the microwell results were subsequently used to

guide the location of monitoring wells and to evaluate relative horizontal and vertical

concentration variations within the VOC plume Water quality data from monitoring wells were

then used to confirm the microwell results and delineate plume boundaries

The results of laboratory metals analyses shown in Table 4-10 and Plate 4-5 do not indicate any

significant source areas on the Site nor are there any apparent trends in occurrence or

concentrations of metals Lead was detected at variable depths and concentrations at a total of 15

microwell locations (TW102 103 104 107 115 120 126 128 139 141 143 148 151 and

5797wpdoclaquogilluprifinaltextmlaquo8terrifhl061297 4-17 QSTEnvironmental


152) These locations represent nearly every portion of the study area With several exceptions

the majority of iiicrowell lead detections were trace to very low (ie lt 10 ugL) Exceptions

included results from single samples collected at locations TW120 (192 ugL) TW-128 (644

ugL) and TW151 (182 ugL) Although several of the locations at which lead was detected are

downgradient of former disposal areas most of the detections were at locations that are either

upgradient or a large distance (400 to 1000 feet) from former disposal areas Furthermore while

lead was detected at some downgradient locations there were other downgradient locations at

which lead was not detected at all It is also noted that lead was only detected at a concentration

of 1 ugL at the microwell (TW143) placed in the center of the Former Primary Disposal Area

and that lead was not detected at all in the two nearest downgradient (relative to the Former

Primary Disposal Area) microwell locations (TW119 and 137) Based on the lack of significant

detections of lead in most microwells on the Site and the fact that metals are typically much less

mobile than VOC the majority of these detections were not considered to be Site related and may

be attributed to an off-site source Numerous off-site activities may have resulted in lead

contaminations including most notably the observed presence of large lead-containing batteries

abandoned along the west side of the railroad bed and fire armhunting activities (as evidenced by

the large number of spent shotgun shell casings observed in the area)

422 Groundwater Monitoring Wells

The initial (Phase 1A) monitoring well network was designed to (1) confirm the findings of the

microwell survey with respect to the chlorinated VOC plume in the northern Study Area and the

two isolated MIBK detections in the southern Study Area and (2) provide hydraulic data to

determine groundwater flow directions and rates An additional objective of the network was to

evaluate potential bedrock groundwater issues related to the Former Seepage Bed which is

located in an area where the water table lies below the base of the overburden formation

Following the Phase 1A monitoring well installation and sampling program additional rounds of

groundwater samples were collected in April July November 1995 February May August

November 1996 and February 1997 under the Long-Term Monitoring Program In October

1995 additional wells were installed during the Phase IB field program to address groundwater

quality and flow directions from areas north of the site The newly installed monitoring wells

(MW117STT MW118STT MW119STT and MW102B) and the existing monitoring wells

located at the former Pervel flock plant (MW-A -B -C -2 and -3) were also included only in

the November 1995 round of groundwater sampling and were sampled only for VOC analyses

Further details of the monitoring well installation program are provided in Section 27 The

following sections present and discuss the groundwater sampling results for VOC SVOC metals

and pesticidesPCB for all nine rounds of sampling

5797wpdocsgalIuprifinaltextmlaquosteiTifhl061297 4-18 QSTEnvironmental


4221 VOC

This section discusses the VOC data collected from groundwater monitoring wells during the nine

sampling events conducted between January 1995 and February 1997 Positive groundwater VOC

detections for the nine sampling events are shown in Tables 4-11 through 4-19 respectively VOC

data for the four 1995 events are presented graphically on Plate 4-6 and the VOC data for the

four 1996 events and the February 1997 event are presented on Plate 4-7

42211 Overburden

Northern Study Area

As shown in Plates 4-6 and 4-7 the monitoring well data for all nine sampling events generally

confirm the microwell survey results with regard to the distribution of VOC downgradient from

the Former Primary Disposal Area

The various VOC detected are grouped into chlorinated VOC (eg TCA TCE 11- and 12shy

DCE tetrachloroethene (PCE) 11-DCA 12-dichloropropane carbon tetrachloride methylene

chloride chloroform and vinyl chloride) and non-chlorinated VOC (eg ethyl benzene toluene

xylene benzene styrene and carbon disulfide) As shown in Plates 4-6 and 4-7 the distribution

of these compounds as reported for the November 1995 and February 1997 sample events

respectively has been used to delineate the horizontal boundaries of a VOC plume which

originates in the vicinity of the Former Primary Disposal Area The plume boundary as depicted

on Plates 4-6 and 4-7 is defined by the locations where any compound was detected in excess of

its respective EPA MCL during the November 1995 and February 1997 sampling rounds

Locations at which VOC were detected at levels greater than their respective MCL during at least one sampling round were MW101(STTT) MW102(STTB) MW105 (STTTB)

MW107(TT) and MW-C (located at the former Pervel flock plant facility) MW116T exceed the

MCL for PCE only and only on one occasion (January 1995 at 17 ppb) VOC in samples

collected from MW116T during the eight subsequent sampling events were all below their

respective MCL At MW101 the only compound which was detected in excess of its MCL was

PCE which was detected in the shallow well at a maximum concentration of 6 ppb in the top-ofshy

till well at concentrations ranging from 15 to 32 ppb and between 22 and 30 ppb in the till well

At MW102S compounds detected in excess of their MCLs were 11-DCE (between 3 and 19

ppb) 12-DCE (between 72 and 670 ppb) PCE (between 10 and 43 ppb) 111-TCA (one

exceedance in July 1995 at 240 ppb) TCE (between 15 and 88 ppb) and vinyl chloride (from not

detected to 86 ppb) At MW102TT compounds that exceeded their respective MCL were 11shy

DCE (from not detected to 35 ppb) 12-DCE (between 140 and 1300 ppb) PCE (above the

MCL during four of the sampling events up to 14 ppb) 111-TCA (one exceedance in August



1996 at 200 ppb) TCE (one exceedence in February 1997 at 7 ppb) and vinyl chloride (from not

detected to 430 ppb) MW102B and MW105S each had a one-time MCL exceedence for only

vinyl chloride both occurrences at 3 ppb (in May 1996 at MW102B and in August 1996 at

MW105S

At MW105TT six compounds have exceeded their respective MCL as follows 11-DCE (up to

32 ppb) 12-DCE (between 150 and 1100 ppb) PCE (up to 9 ppb) 111-TCA (between 37 and

390 ppb) TCE (two exceedences up to 14 ppb) and vinyl chloride (from not-detected to 710

ppb) MCL exceedences detected at MW105T are as follow 11-DCE (two exceedences both at

12 ppb) 12-DCE (between 43 and 430 ppb) 111-TCA (one exceedence 380 ppb in February

1996) TCE (one exceedence 27 ppb in November 1995) and vinyl chloride (from not detected

to 1400 ppb) The only compound that exceeded its respective MCL in MW105B is 12-DCE

(between 2 and 180 ppb) MW107TT has had MCL exceedence of the following three

compounds 11-DCE (from not detected to 16 ppb) 12-DCE (between 72 and 1100 ppb) and

vinyl chloride (between 120 and 430 ppb)

Although there is some variation in the distribution and concentration of VOC with each sample

event the plume defined by the November 1995 data set (as shown on Plate 4-6) is nearly

identical to the plume defined by the February 1997 data set (as shown on Plate 4-7) Further

discussion of VOC concentration variations with time is provided in Section 52

Typically VOC in wells located beyond the boundaries of the plume were detected at estimated

or trace to very-low concentrations and were not detected with any regularity VOC were

detected at low levels in at least two-thirds of the samples collected from the following wells

located beyond the boundaries of the plume MW103TT (12-DCE and PCE) MW108B 11shy

DCE PCE and TCA) MW116T (PCE and TCA) SW3S (12-DCE PCE and 11-DCA) and

SW3D (12-DCE TCA and 11-DCA) PCE was detected in excess of its MCL at location

MW116T (17 ppb) during the first sampling event (January 1995) but it was never detected

above 3J ppb in the eight subsequent sampling events

TCA and 12-DCE which were detected in wells at all three locations along the plume centerline

(ie MW107 MW105 and MW102) appear to be good tracers for assessing contaminant

migration away from the Former Primary Disposal Area Based on 1995 data these compounds

have been incorporated into contaminant travel-time analyses presented in Section 5 At locations

MW107 and MW105 the highest concentrations were measured in the top-of-till wells with only

low to trace levels in the shallow wells (TCA and 12-DCE concentration up to 130 ppb and

1100 ppb respectively in MW107TT and up to 390 ppb and 1100 ppb respectively in

MW105TT At location MW102 TCA and DCE were detected at similar concentrations (up to



240 and 1300 ppb respectively) in shallow and top-of-till wells For all sampling dates TCA

concentrations in the top-of-till wells along the plume centerline varied from 24 to 390 ppb and

12-DCE levels in the top-of-till wells along the plume centerline ranged from 72 to 1300 ppb

No significant reduction in TCA or 12-DCE concentrations with distance from the Former

Primary Disposal Area is apparent at locations MW107 MW105 and MW102

TCE 11-dichloroethane ethyl benzene benzene 11-DCE 12-dichloropropane PCE toluene

vinyl chloride and xylenes were also detected at each of the three plume centerline locations but

as shown in Plates 4-6 and 4-7 their concentration distributions were more sporadic and TCE

11-DCE PCE and vinyl chloride were the only compounds that exceed their respective MCL

during at least one sampling event TCE was found at concentrations up to 88 ppb (in well

MW102S) 11-DCE was found at concentrations up to 35 ppb (in well MW102TT) the

maximum PCE concentration was measured at 43 ppb (in well MW102S) and vinyl chloride was

measured as high as 1400 ppb (well MW105T) The second highest vinyl chloride value was

710 ppb (well MW105TT) and all other vinyl chloride measurements ranged from not-detected up

to 430 ppb

Wells located within the northern portion of the Site where VOC have never been detected include

MW106TT MW109B and MW110S

Based on the monitoring well and microwell results concentrations within the VOC plume appear

to be relatively evenly distributed throughout the lower three-quarters of the aquifer thickness

Throughout most of the plume area (eg MW107 MW105 and MW101) VOC levels in the

upper five to 15 feet of the aquifer are typically near the detection limit The concentration

reduction near the water table is likely associated with rainwater infiltration Evidence of

infiltration includes the consistently downward hydraulic gradients at MW107 MW108 and

MW116 At these locations the vertical hydraulic gradient is on the order of a factor of 100

greater than the horizontal hydraulic gradient within the VOC plume Location MW102 where

shallow and deep concentrations are similar in magnitude is an exception to this trend of low

concentration near the water table A plausible explanation for the observed concentrations in

MW102S is the hydraulic influence of Mill Brook which as discussed in Section 3323 causes

upward flow in the upper portion of the aquifer near the brook Upward flow near the brook and

MW102S is also supported by the upward hydraulic gradients measured between MW102S and

the stream piezometer PZ-4B

The present PCE distribution in groundwater exhibits inconsistencies with migration from the

Former Disposal Areas PCE was consistently detected at levels above the 5 ppb MCL up to 43

ppb in groundwater samples from wells MW102S MW101TT and MW101T PCE was

5797wpdocraquogalluprifinaltextmasterrifhl061297 4-21 QST Environmental


measured in well MW116T at 17 ppb in the initial sampling round (January 1995) and

consistently at trace levels in subsequent sampling rounds However only trace levels of PCE

were detected at the MW105 or MW107 locations and the only occurrences of PCE at MW105

or MW107 greater than 5 ppb were three estimated detections of 6 7 and 9 ppb at MW105TT

PCE was not detected in well SW3S and was detected once at a trace level in well SW3D

Monitoring wells MW102 and MW101 are downgradient from both the Former Disposal Areas

and the former Pervel flock plant where PCE TCA and DCE groundwater contamination has

been documented (Section 52) During the November 1995 sampling event VOC detected at

MW-C (located at the former Pervel flock plant) include DCE (97 ppb) TCE (11 ppb) and PCE

(24 ppb) Based on available data MW116 is located downgradient from the former Pervel

flock plant Groundwater flow conditions in the past would need to have been different from

present conditions for MW116 to be downgradient from the Former Disposal Areas Although

the PCE detections at locations MW102 and MW101 could be attributable to historical releases

from the Former Disposal Areas the regional flow pattern and spatial distribution of PCE in

groundwater suggest that contamination from the former Pervel facility has at a minimum

contributed to VOC (PCE TCA and DCE) contamination of these locations Further discussion

of the PCE detections and other VOC concentration variations is provided in Section 52

Southern Study Area

In the southern portion of the Study Area groundwater samples were collected from overburden

monitoring wells at five locations SW9 MW112 MW113 MW114 and MW115 As shown

on Plates 4-6 4-7 no VOC were detected in any of the wells As a result of the consistent lack of

detections wells at these locations were dropped from the Long-Term Monitoring Program (with

EPA approval) after three sampling events These data are consistent with the microwell survey

results but do not support the low-level detections of methyl isobutyl ketone in the two microwell

samples (Section 421)

42212 Bedrock

During the RI VOC were detected in bedrock wells at the following locations MW102 MW105

MW107 MW108 and SW-10 Since the only VOC detected at SW-10 was TCA at an estimated

trace concentration (1J ppb) during the January event and TCA was not detected in SW-10

during the subsequent two sampling events this well was eventually dropped from the Long Term

Monitoring Program (with EPA approval) following the July event All other bedrock wells in

the southern portion of the Study Area (MW111 MW112 MW113 SW-12) were likewise

dropped from the monitoring program At location MW108B estimated concentrations of PCE

(3J ppb) and TCA (up to 9J ppb) were detected during the January and April sampling events

therefore samples collected from this well during the July and November events were submitted

5797wpdocsgalluprifinaltextmasterriftil061297 4-22 QST Environmental


for VOC analyses using EPA Method 5242 which hs lower detection limits than the TCL

Methods The results of the July and November events for MW108B indicate that other VOC are

present but generally at trace to very low concentrations The highest detections of TCA and

PCE at this location were 92 and an estimated 5 ppb respectively Other VOC detected at

MW108 were carbon tetrachloride (12 ppb) 11-DCA (1 ppb) 12-DCA (015J ppb) 11-DCE

(13 ppb) and xylene (01J ppb)

The only VOC detected at MW107B was TCA which was measured during three events at

concentrations ranging between 059J and 2 ppb Over the nine sampling events VOC detected

at MW105B included 11-DCA (BDL to 9J ppb) 11-DCE (BDL-4J ppb) 12-DCE (11-140J

ppb) 12-dichloropropane (2J ppb in January 1995 and February 1996 only) TCA (2J-12 ppb)

and TCE (BDL-3J ppb)

MW102B was installed during the Phase IB investigation and therefore was only sampled during

five events VOC detected at MW102B were typically at estimated trace concentrations and

only PCE was detected in every round (2J to 4J ppb) The only MCL exceedence was a single

estimated detection of vinyl chloride (3J ppb)

In general VOC detected in bedrock wells were also detected in overburden wells at the same

locations although the concentrations seen in the bedrock wells are significantly lower typically

by an order of magnitude relative to concentrations seen in the top-of-till wells The only

notable exception to this trend is at location MW108 where VOC were not typically detected in

the overburden wells (with the exception of an estimated 2J ppb of DCE detected once in

MW108S and once in MW108TT) At MW105 and MW107 VOC concentrations seen in the till

wells are similar to the low concentrations detected in wells screened in the underlying bedrock

The low VOC levels detected in bedrock wells located in the northern portion of the Study Area

demonstrate that bedrock is not a preferred pathway for contaminant migration This conclusion

is supported by the groundwater hydraulics data outlined in Section 3323 which demonstrate

that the average hydraulic conductivity of the bedrock is more than a factor of 200 less than the

overburden hydraulic conductivity In spite of the upward hydraulic gradient from bedrock to

overburden (factor of ten to 100 larger than the horizontal hydraulic gradient within the VOC

plume) which was found to exist throughout the Study Area vertical (transverse) dispersion

caused by flow in the bedrock fracture system has apparently caused VOC to migrate a limited

distance into the bedrock

5797wpdocsgalIuprifinaltextmasterrifhl061297 4-23 QST Environmental


4222 Semivolatile Organic Compounds

Tables 4-20 through 4-28 present the analytical results for SVOC in groundwater for the nine

sampling events Overall SVOC were detected infrequently and generally at only trace levels

Naphthalene 2-methylphenol and 12-dichlorobenzene were the most frequently detected SVOC

compounds in groundwater samples Naphthalene was detected during every sampling event

generally at MW105 MW107 and MW102 locations within the top-of-till wells and occasionally

also within till at well MW105T The highest naphthalene measurement was 10 ppb in

MW105TT 2-methylphenol was also detected during every sampling event always in well

MW107TT and with lesser frequency in MW105TT MW105T and MW102TT the highest

concentration detected was 3 ppb In eight of the nine sampling events 12-dichlorobenzene was

detected in at least one of the following wells MW102TT MW105TT MW105T MW107TT

and the maximum concentration measured was 4 ppb Maximum bis(2-ethylhexyl)phthalate was

detected in at least one well during six of the nine sampling events the concentrations ranged

from 04J to 35 ppb The locations of the bis(2-ethylhexyl)phthalate detections were sporadic it

was detected three times at MW108S twice at MW014S and MW116T and only once at eleven

wellsTrace levels of the following other compounds were detected during various sampling

events acenaphthene (03J ppb) butylbenzylphthlate (U ppb) di-n-butylphthlate (04J ppb) 4shy

chloroaniline (2J ppb) 24-dichlorophenol (U ppb) fluorene (06J ppb) 4-chloro-3-methylphenol

(2J ppb) phenanthrene (02J ppb) 4-bromophenyl-phenylether (2J ppb) n-nitroso-di-nshy

propylamine (9J ppb) 14-dichlorobenzene (up to 2J ppb) diethylphthlate (up to 04J ppb) 24shy

dimethylphenol (up to 8J ppb) di-n-octylphthlate (up to 46B ppb) 4 methylphenol (2J ppb) and

phenol (up to 4J ppb) The majority of these compounds occur in either the till or top-of-till

wells located within the VOC plume shown on Plates 4-6 and 4-7 (eg MW102 MW105 and

MW107) although there were infrequent detections of compounds at MW103 MW104 MW106

MW108 MW109 SW3D MW112 and MW116 as well

4223 Pesticides and PCB

The only detection of PCB in groundwater was during the April event when Aroclor 1242 was

detected in MW103S and TT at estimated concentrations of 042J and 018J ppb respectively

Estimated low levels of a few pesticides were detected in a small number of groundwater samples

Endosulfan I was detected once (002J ppb in MW107S during April 1995) Endrin was detected

once (00031 JP in MW109S during February 1996) methoxychlor was detected once (012J in

MW107S during February 1997) alpha-BHC was detected once in four wells (during February

1997 up to 0011 JP ppb) beta-BHC was detected twice up to 004J ppb (at MW107S in July

1995 and at MW107TT in February 1996) and gamma-BHC was detected in three samples up to

001JP (at MW105B and MW116S during November 1995 and at MW102S during August 1996)

All positive detections for pesticide and PCB compounds are shown on Table 4-29 (Note Table

5797wpdocraquogalluprifinflltextmasterriftil061297 4-24 QSTEnvironmental


4-29 only includes those sample IDs where a pesticide or PCB compound has ever been detected)

4224 Inorganics

Tables 4-30 through 4-38 present the analytical results for total (and where applicable dissolved)

metals in groundwater (During sampling low flow purging techniques were used to minimize

disturbance of formation water In cases where turbidity levels less than 5 NTU could be

achieved samples for both total and dissolved metals were collected Otherwise samples were submitted for total metals analyses only) Cyanide has not been detected in any groundwater

sample Metals were generally not detected in groundwater above applicable MCLs and metals

in groundwater samples across the Study Area were similar in concentration to metals detected in

designated groundwater background samples

Analytical results of a duplicate sample collected from MW107S during August 1996 had

anomalously high values Between January 1995 and August 1996 nine samples (seven rounds

plus two duplicate samples) were collected from this well and analyzed for total metals Only one

sample contained inorganic compounds in excess of EPA MCLs or Connecticut Remediation

Standards This sample which was the duplicate sample collected in August 1996 contained

elevated concentrations of aluminum chromium cobalt magnesium manganese and nickel In

order to evaluate the significance of this particular data set a statistical analysis for the

identification of outliers was performed following the procedures described in the EPA guidance

document Statistical Analysis of Ground Water Monitoring Data at RCRA Facilities (EPA530shy

SW089-026) For this analysis a test statistic (TJ was generated (using the average maximum

and standard deviation) from the nine samples for each inorganic analyte detected in this well If

the test statistic was greater than a critical value (1764) representing a 995 level of

significance then there is a strong likelihood that the maximum value for each data set is a statistical outlier If a given analyte was not detected in a given sample the detection limit2 was

used for statistical calculations

Maximum concentrations for nine of the thirteen analytes that have been detected in this well

were found to be statistical outliers Six of the statistical outliers were found in the MW107S

duplicate sample collected in August 1996 which suggests that the inorganic data from this

particular sample are not representative of groundwater quality in the immediate vicinity of this

well Although a specific reason why this sample contained such anomalously high levels is not

apparent it seems clear that this sample is not representative of the actual groundwater metal

concentrations at this location This is supported by the fact that the other sample from this well

on this date has metals concentrations consistent with previous sampling rounds Therefore the

metals data from this duplicate sample have been presented in this Report but are considered not

to be valid

5797wpdocBgalluprifinaltextmasterrifhl061297 4-25 QSTT Environmental


4225 DioxinsFurans and Additional Appendix IX Parameters

During the January 1995 sampling event samples from three locations (MW102TT MW106TT

and MW116T) were submitted for laboratory analysis for full Appendix IX parameters During

the April 1995 sampling event samples from MW105TT were also submitted for full Appendix IX

analyses The results for the VOC SVOC PesticidePCB and metals analyses for these samples

have been included in the appropriate tables as discussed in previous sections The results of

Appendix IX analyses that are not common to target analyte and target compound lists

(TALTCL) are discussed below Analyte groups specific to the Appendix IX lists include

herbicides (EPA Method 8150) volatiles by direct aqueous injection (EPA method modified

8015) Phenols (EPA Method 4202) Sulfide (EPA Method 3761) Organophosphorus Pesticides

(EPA Method 8141) PesticidesPCB by EPA Method 8080 and DioxinsFurans

The only detections for any of the analyte classes specific to Appendix IX compounds during the

January 1995 event were phenols (MW102TT at 7 ppb and MW116T at 15J ppb) During the

April 1995 event the dioxinfuran compounds HxCDD (total) and TCDF (total) were detected at

MW105TT at concentrations of 705 and 193 ngL (part per trillion)

423 Residential Wells

Residential wells were sampled during the Phase 1A investigation (January 1995) and again

during July 1995 February 1996 and August 1996 under the Long-Term Monitoring Program

4231 Volatile Organic Compounds

Tables 4-39 through 4-42 present the results of VOC analyses for residential well samples The

locations of these wells are shown on Plate 2-5 TCA was detected at DW114 during all four

sampling events and was also detected once at DW111 and DW113 the concentration ranged

from 018J to 066 ppb Chloroform was detected during three of the sampling events twice at

DW102 and once at DW104 and DW107 the maximum concentration detected was 19 ppb The

following compounds were also detected at low levels once bromodichloromethane (2 ppb at

DW107) dibromochloromethane (084J ppb) PCE (016J ppb at DW114) chloromethane (082J

ppb at DW103) and at DW111 ethylbenzene (025J ppb) toluene (012J ppb) and xylenes

(0 U) Since these locations are not downgradient with respect to the Site the occurrence of

these compounds in these wells are not likely to be Site related


No SVOC were detected in any residential well sample during any of the four sampling events

5797wpdocsgalIuprifinaltextmasterrifhl061297 4-26 QT Environmental


4233 Pesticides and PCS

Tables 4-43 through 4-46 present the analytical results of pesticide and PCB analyses for

residential well samples Alpha-chlordane and gamma-chlordane were both detected in all four samples collected from DW105 and in three of the samples collected from DW106 The

maximum concentrations measured were 0095 ppb for alph-chlordane and 004 ppb for gamma-chlordane During August 1996 44-DDE and heptachlor epoxide were both also detected at

DW105 and DW106 (001J ppb for 44-DCE and up to 002J ppb for heptachlor epoxideNo PCB compounds were detected in any residential well The fact that DW105 and DW106 are not

downgradient relative to the site indicate that these compounds are likely attributable to the off-site use of these pesticides and are not site-related

4234 Inorganics

Tables 4-47 through 4-50 present the analytical results of metals and cyanide analyses for

residential well samples for the four sampling events Heavy metals were generally not detected

or were detected at trace levels Alkaline earth metals (eg Ca Mg K) were detected at levels

not unexpected for natural groundwater in the region

43 Surface Water Sediment and Wetland Soils Surface water sediment and wetland soils upstream adjacent to and downstream of the Site

were sampled and analyzed during the Phase 1A investigation to assess the potential if any for

transport of constituents of concern from the Site Sample locations are shown on Plate 2-6 Sediment was collected from one additional location (UB-6A) during the April 1995 sampling round As part of the Long Term Monitoring Program additional rounds of surface water

samples were collected during the April and November 1995 and May and November 1996

sampling events The samples were analyzed for VOC SVOC metalscyanide and pesticidePCB with the exception of the November 1996 samples which with EPA approval

were analyzed only for VOC and metals It is noted that following the Phase 1A sampling event

(September 1994) stations UB-1 UB-2 and UB-3 were eliminated from the Long Term

Monitoring Program (with EPA approval) as these locations are upstream of station UB-4 which

is also upstream from the Site Also station UB-6 (which was located on a tributary to Mill

Brook and sampled during the Phase 1A program) was replaced by station UB-6A (located within

Mill Brook) during the four Long-Term Monitoring events

431 Surface Water During September 1994 water quality indicators (pH dissolved oxygen temperature

conductivity turbidity) were measured in the field at eleven surface water sampling stations six

in Upper Mill Brook two in Lower Mill Brook (below the confluence with Fry Brook) one in

Fry Brook and two in Packers Pond The remaining six locations were dry at the time of

5797wpdocsgalluprifinaltextmlaquosterrifhl061297 4-27 QSTEnvironmental


sampling As presented in Table 4-51 the water quality of the watershed as judged by both field

measurements and wet chemistry (TSS alkalinity hardness) was good to excellent It may

however be important to note that all of the samples were taken under fair weather conditions so

the influence of potential non-point sources during storm events cannot be assessed with this data

set Table 4-51 presents a qualitative assessment (eg slight moderate obvious) of potential

Local Non-Point Source Pollution As most sampling stations are either adjacent to or

downstream from developed (eg streets highways residences agricultural or industrial

property) the immediate andor cumulative impact of storm events cannot be evaluated in this

report During the four Long-Term Monitoring surface water sampling events field parameters

were again measured The results of these sampling events are shown in Table 4-52

During the September 1994 Phase 1A investigation surface water temperature ranged from 60 degF

(UB1 UB2) to 70degF (PP3) Surface water at most locations contained adequate concentrations of

dissolved oxygen ranging from 335 (UB2) to 1035 (UB8) mg1 but were slightly acidic with

pH varying from 528 (UB1) to 572 (PP3) Dissolved solids measured indirectly as specific

conductivity varied from 120 (UB1) to 710 (PP3) imhoscm

During the four Long-Term Monitoring sampling events surface water temperatures ranged from

526 to 617degF in April 1995 and 420 to 508degF in May 1996 to seasonally lower temperatures

of 396 to 453degF in November 1995 and 374 to 400degF in November 1996 The dissolved

oxygen concentrations were generally similar between the various sampling events ranging from

a low of 335 mg1 (at UB-2 in September 1994) to a high of 1030 mg1 (at PP-1 in November

1996) pH measurements indicated slightly acidic water with the following ranges 514 to 605

in April 1995 574 to 667 in November 1995 615 to 701 in May 1996 and 472 to 620 in

November 1996 Conductivity values were in the same general range between the different

sampling events with the lowest measurement of 1 anhoscm at PP-1 in November 1996 and the

highest measurement of 523 xmhoscm at UB-5 in April 1995

Based on laboratory results surface water in the area is fairly soft ranging in hardness (as

CaCO3) from 12 (TR-1 during April 1995) to 179 (UB2 during September 1994) mg1 and in

alkalinity from lt 1 (UBS during April 1995) to 67 (UB2 during September 1994) mg1 Total

dissolved solids and total organic carbon were below 200 ppm and 15 ppm respectively at nearly

every station during all five sample events A total of 58 total suspended solids analyses were

performed on samples collected during the five sampling events Most of the results were below

the detection limit and only 10 samples exceeded 10 mg1 The highest concentrations were

detected at UB-5 (between 82 and 2470 mg1 in the four samples collected at that location) and at

PP-1 (between 87 and 1500 mg1 in the three samples collected at that location)


Gallups Quarry Supcrjund Project - Remedial Investigation

4311 VOC- Surface Water

Data presenting he concentrations of various VOC for each individual surface water location are

presented in Table 4-53 through 4-57 for the September 1994 April and November 1995 and

May and November 1996 sampling events respectively VOC were not detected in the upstream

portion of Mill Brook Six VOC were detected at least once in the five rounds of surface water

samples collected from 11 locations The most consistent detections were 12-DCE and PCE in

Fry Brook sample FB-1 12-DCE was detected every round at FB-1 and occasionally at four

other locations up to 8J ppb and PCE was detected every round at FB-1 and occasionally at

three other locations up to 11 ppb Sample location FB-1 is approximately 1500 feet upstream

of the confluence of Fry Brook and Mill Brook the detections at FB-1 are not likely to be Site-

related and may result from nearby industrial activities The other detections of PCE and DCE

were at trace concentrations at locations below the confluence of Fry and Mill Brooks In

addition TCA was detected once at UB-10 at 3J ppb TCE was detected twice at FB-1 and once

at UB-9 up to 2 ppb carbon disulfide was detected in seven samples representing six locations

up to 20 ppb and toluene was detected twice at upgradient location UB-5 at 1J ppb All of the

VOC concentrations detected are well below those expected to cause adverse effects in fish or

wildlife (USEPA 1986)

4312 SVOC - Surface Water

During the September 1994 sampling event only low levels of one SVOC compound 4shy

methylphenol (28 ppb PP3 1 ppb UB2) were detected in surface water samples The locations

where SVOC were detected are far upstream (UB 2) and downstream (Packer Pond) locations and

are unlikely to have been impacted by the Site During the April 1995 sampling event the only

SVOC detected were trace levels of fluoranthene (04J ppb) phenanthrene (03J ppb) and pyrene

(04J ppb) all of which were detected at UB-5 which is upstream from the site There were no

SVOC detected in any surface water samples during the November 1995 event During the May

1996 sampling event bis(2-ethylhexyl)phthalate was detected in four samples at concentrations

ranging from 05J ppb to 140J ppb The locations of the detections are upgradient of the Site

(UB-5 and UB-8) and downgradient of the Site (LB-2 and PP-1) The sample from LB-2 also had

an estimated low level of di-n-octylphthalate (7J ppb) Table 4-58 presents all of the SVOc

detections in surface water samples (Note Table 4-58 only includes those sample IDs where a

SVOC has ever been detected)

4313 PesticidesPCBs - Surface Water

No pesticides or PCB compounds were detected in any surface water samples

5797wpdocsgalluprifinaltextmraquosterrifhl061297 4-29 Q5T Environmental


4314 Total and Dissolved Metals - Surface Water

Because of the ubiquity of naturally occurring metals in surface waters metals results are more

easily interpreted by generating descriptive statistics Descriptive statistics for metals measured in

surface water during 1994 and 1995 are presented in Appendix S Data presenting total and

dissolved metals concentrations for each individual sampling location during all five sampling

events are presented in Tables 4-59 through 4-65

Total Metals

Cadmium silver and thallium were not detected in any samples during the five sampling events

Other constituents detected in only one or two samples during each event include arsenic (up to

296J ppb) beryllium (once at 26B ppb) chromium (up to 764 ppb) cobalt (up to 26 IB ppb)

copper (up to 165 ppb) cyanide (up to 466 ppb) mercury (once at 018B ppb) nickel (up to

821 ppb) selenium (181J ppb at PP3) silver (once at 3J ppb) and vanadium (133 ppb) With

die exception of station UB2 during the September 1994 sampling event UB-5 during die April

1995 May 1996 and November 1996 events and PP-1 during the May and November 1996 events the remaining metals (aluminum barium calcium iron lead magnesium manganese

potassium sodium and zinc) were detected at concentrations that are expected in natural waters

(Hem 1989)

Dissolved Metals

Beryllium cadmium cobalt mercury selenium and thallium were not detected in any sample

Constituents detected infrequently and at low concentrations include antimony arsenic

chromium nickel silver vanadium and zinc Copper was detected at several locations upstream

and downstream from the site at concentrations ranging from 25 to 208B ppb although there

was no pattern in its occurrence or concentration Lead was detected at least once at each of the

sampling locations ranging in concentration from 1J ppb to 188 ppb The occurrences of lead

did not show a pattern die highest measurements were as follows 11 ppb at PP-3 in September

1994 188 ppb at UB-9 in April 1995 16J ppb at UB-4 in November 1995 56J ppb at UB-5 in

May 1996 and 91J ppb at UB-5 in November 1996 Locations UB-4 and UB-5 are upgradient

of the Site The lead detections in Packer Pond samples likely results from non-point sources to

Packers Pond The remaining metals (aluminum barium calcium copper iron lead

magnesium manganese potassium and sodium) were detected at concentrations that are expected

in natural waters (Hem 1989)

Concentrations of total and dissolved metals in surface waters were generally detected infrequently

and at concentrations below ambient water quality criteria ie those that would not pose a threat

5797wpdocsgalluprifinraquoItextmaBterriftil061297 4-30 QST Environmental


to fish or wildlife (EPA 1986) Heavy metals such as copper and lead generally considered

harmful to aquatic life were detected at locations (Fry Brook and Packers Pond) that are not

likely to be impacted by the Site One location UB-5 (which was dry during September 1994)

contained elevated levels of most metals during the 1995 and 1996 sampling events This sample

station is located well upstream from the site on a tributary to Mill Brook which originates in a

small pond adjacent to Interstate 395 in a highly commercialized area

432 Sediment

A total of seventeen sediment samples were collected during the Phase 1A field survey

(September 1994) six of which were dry at the time The composition of the sediment samples

varied from deep muck (eg LB-02) to a firm sandy substrate (eg UBS) The total organic

carbon (TOC) content of the sediments (presented in Table 4-30) ranged from 075 (UB4) to 16

(PP1) percent with an average of 57 percent

4321 Inorganics - Sediment

Because of the ubiquity of naturally occurring metals in sediment these constituents are more

easily interpreted by generating descriptive statistics which are presented for each individual

metal in Appendix S Data presented for metals at each individual sampling location are

presented in Table 4-66

Antimony and thallium were not detected above the detection limit Beryllium cadmium

chromium cyanide mercury selenium and silver were detected infrequently and when detected

had concentrations close to the respective detection limit andor were detected at remote upstream

or downstream locations With the exception of maximum concentrations detected at PP3 (a

location at Packer Pond which receives stormwater runoff from Lillibridge Road) the remaining metals (aluminum arsenic barium calcium cobalt copper iron lead magnesium manganese

nickel potassium sodium vanadium and zinc) were detected at concentrations within the ranges

expected in naturally occurring soils or sediments (Beyer 1990 Fitchko 1989 Shacklette and

Boerngen 1984)

4322 VOC - Sediment

Analytical results for concentrations of VOC in sediment samples are presented in Table 4-41

VOC were generally detected infrequently and at relatively low concentrations in sediments

Ketones (acetone and 2-butanone) were detected at remote upstream (UB1 UB6) and downstream

(PP1 PP2 PP3) locations One or more of the compounds toluene trichloroethene methylene

chloride and xylenes were detected at trace levels at upstream locations north and east of the Site

(UB-3 UB-5 UB-6 UB-7 and UB-9) Xylenes were detected at a concentration of 31 pm in the

sediment sample from Fry Brook (FB-1) Only toluene at trace level of 0009J ppm was

5797wpdocsgalluprifinaltextma8terrifhl061297 4-31 QST Environmental


detected in the sediment sample from UB-10 located in Mill Brook near the downgradient edge

of the Gallups plume No VOC were detected in sediment samples from downstream locations

LB-1 and LB-2

4323 SVOC - Sediment

As shown on Table 4-68 the primary SVOC constituents detected were PAH ranging from non-

detect (~ 03 ppm) to 15 ppm No apparent concentration gradient could be determined with

respect to location (eg upstream to downstream) The detections of PAH likely reflect non-

point contributions from local sources such as stormwater runoff from the railroad tracks and

nearby roads

Elevated concentrations of bis(2-ethylhexyl)phthalate were measured in Fry Brook (1300 ppm

FBI) and lower Mill Brook (64 ppm LB2) below the confluence of these two streams The

source appears to originate in Fry Brook

4324 PesticidesPCB - Sediment

Analytical results for pesticides and PCB are provided on Table 4-69 PCB compounds

(Arochlor-1242 -1254 and -1260) were detected in sediment samples from only three locations

all upstream (FB-1 at 019 ppm UB-8 at 0023J ppm and UB-7 at 00064J ppm)

Organochlorine pesticide compounds were also detected infrequently with no apparent trend with

regard to location or source The concentrations in sediment ranged from non-detect (~ 1-3 ppb)

to 39 ppb (methoxychlor at PP1) and their occurrence likely reflects residues of persistent

compounds that were routinely used for insect control before being banned from commercial

production

433 Wetland Soils

A total of 10 wetland soil samples were collected during the field survey most of which were

close to the water table at the time of collection The wetland sampling locations are shown on

Plates 2-6 and 3-14 The total organic carbon content (mgkg) of the wetland soils is as follows

QW1 (160000) QW2 (54600) QW3 (37200) QW4 (35200) QW5 (23900) QW6 (25600)

QW7 (gt 160000) QW8 (gt 160000) QW9 (33600) and QW10 (42600)

4331 Inorganics - Wetland Soils

Because of the ubiquity of naturally-occurring metals in wetland soils these constituents are more


metal in Appendix S Analytical results for metals at each individual sampling location are


5797wpdocsgalluprifinaltextmasterrifhl061297 4-32 QSTEnvironmental


Cadmium and cyanide were not detected in any sample Antimony arsenic beryllium cobalt

mercury selenium silver and thallium were detected infrequently and at trace levels at or below

the detection limit None of the remaining metals (aluminum barium calcium chromium

copper iron lead magnesium manganese nickel potassium sodium vanadium and zinc)

exceeded normal ranges expected for naturally occurring soils (Beyer 1990 Fitchko 1989

Shacklette and Boerngen 1984)

4332 VOC - Wetland Soils

Analytical results for VOC in wetland soils are provided on Table 4-67 VOC including acetone

2-butanone TCE and carbon disulfide were detected infrequently and at low concentrations

Acetone concentrations ranged from non-detect to 056 ppm (QW8) and 2-butanone concentrations

ranged from 0004 ppm (QW10) to 0067 ppm (QW8) QW8 is located in a remote wooded

location approximately 2000 feet west of the Site QW10 is located a few hundred feet west of

the southern portion of the Site

Acetone and 2-butanone were also detected at lower concentrations (015 and 0033 ppm

respectively) at location QW-1 several hundred feet southeast of the Former Primary Disposal Area A trace level of TCE (0004J ppm) was detected in wetlands soil sample QW-2 collected

approximately 50 feet east of the Former Primary Disposal Area This detection may be related

to the Former Primary Disposal Area since TCE has been detected in this area Based on the

topography however surface water runoff from the former disposal area is unlikely to impact the

wetland No other wetland soil samples had concentrations detected above the instrument

detection limit

Although the source of these VOC is unknown acetone 2-butanone and carbon disulfide are all

commonly used in the laboratory and may have been introduced during post-processing sampling

Some of these compounds are organic solvents that are (or were ) commonly used in many

household (eg spot removers paint strippers aerosols) commercial (eg pesticide

formulations inks and dyes) and industrial (eg degreasers) products Their presence in

wetlands soils samples at low concentrations may be the result of localized human activity in the

area

4333 SVOC - Wetland Soils

Analytical results for SVOC in wetland soils are provided on Table 4-68 The primary

constituents detected were the phthalate esters and PAH PAH were detected infrequently at

generally below 01 ppm Phthalate esters were also detected infrequently ranging from non-

detect to 22 ppm (QW8) The presence of these compounds is likely to be associated with

periodic or seasonal flooding of wetlands as the wetland sampling locations are remote and

5797wpdocsgpluprifinaltextma8terrifhl061297 4-33 QST Environmental

Gallups Quarry Superjimd Project - Remedial Investigation

generally inaccessible except on foot Since these compounds are relatively immobile except in

surface water or as airborne particulates these compounds may have originated from non-point

sources such as the railroad line or runoff from nearby highways

4334 PesticidesPCB - Wetland Soils


(Arochlor-1242 -1254 and -1260) were detected infrequently and at low concentrations

The presence of trace levels of PCB compounds in wetland soil samples QW-1 QW-2 QW-3

and QW-4 may be Site-related however PCBs are ubiquitous environmental contaminants that

were widely used in industry and may thus be present in soils as a result of past activities at

surrounding industries Other sources of input into the local environment might include

atmospheric deposition transport from upstream sources and deposition following flood events


regard to location or source The concentrations in wetland soils ranged from non-detect to 0016

ppm (44-DDE at QW1) and their occurrence likely reflects residues of persistent compounds

that were routinely used for insect control before being banned from commercial production

44 Air Quality 441 Baseline Air Quality Survey

Ambient air quality was determined prior to the start of Phase 1A intrusive investigations to

establish a baseline for air quality For the baseline survey air quality in the breathing zone

(between approximately three and six feet above the ground surface) was determined based on

measurements of total VOC (using a PID equipped with an 117 eV lamp) and respirable dust

(using a aerosol meter) at eight locations across the Site These eight stations were located at

each of the three known Former Disposal Areas and at upwind and downwind locations along the

perimeter of the Site The locations of the eight baseline air monitoring stations (AM1-AM8) are

shown on Plate 2-1 During the baseline survey no VOC readings were detected above the EPA

approved action level of 1 ppm at any of the eight monitoring locations Also no respirable dust

readings greater than the EPA-approved action level of 005 mgm3 were recorded during the

baseline survey at any of the monitoring stations

442 Perimeter Air Monitoring

Throughout the duration of the Phase 1A field investigations ambient air quality was monitored

on a weekly basis at the eight stations for the same parameters described above In addition to

the eight air monitoring stations continuous air monitoring was performed at each discrete

investigation area (eg each microwell soil boring etc) in the workers breathing zone and at the

5797wpdocsgaIIuprifinaltextmasterrifhl061297 4-34 QST Environmental


perimeter of each task specific exclusion zone Air monitoring in the work zones was augmented

with instruments to measure hydrogen cyanide and lower explosion levels Also compound

specific calorimetric equipment (eg Draeger tubes) were used to compliment total VOC

measurements recorded with a PID

No readings above ihe EPA-approved action levels were recorded at the perimeter of the Site

throughout the entire duration of the Phase 1A investigation Elevated worker breathing zone

readings for total VOC were recorded during two of the four soil borings performed within the

Former Primary Disposal Area (SB109 and SB110) Varying but sustained elevated VOC

readings in the workers breathing zone during these two soil borings required the use of OSHA

Level C protection equipment These VOC vapors appeared to dissipate rapidly as no elevated

readings were recorded at the downward perimeter of the exclusion zone

Based on the baseline and periodic air monitoring performed during the investigation undisturbed

ambient air quality in the vicinity of the Site does not appear to have been impacted by former

disposal practices at the Site To confirm this compound specific air monitoring was performed

during the Phase IB investigation

As part of the Phase IB investigation quantitative air monitoring was performed in the vicinity of

the Former Primary Disposal Area The following compounds were detected in shallow soil

during the Phase 1A investigation and therefore were the target analytes for the air monitoring

performed during the Phase IB investigation toluene ethyl benzene total xylenes

tetrachloroethene and PCBs Data from the Phase IB investigation indicate that none of these

compounds were present at any of the air sampling locations for the duration (approximately eight

hours) of the sampling event The laboratory results of these analyses are presented in Appendix

T

45 Potential Sensitive Human Receptors The survey was used to identify any water supply wells schools nursing homes and day care

facilities including in-home day cares within a one-mile radius of the Site

Water Supplies

There are three community water companies serving portions of the Plainfield area within a one-

mile radius of the Site the Gallup Water Company Brookside Water Company and Glen Acres

Water Company The Gallup Water Company operates two wells located in downtown

Plainfield approximately 4000 feet north of the Site The Gallup Water Company presently

services approximately 700 households and three schools (Plainfield Middle School Plainfield

5797wpdocsgalluprifinaltextmlaquoraquoterriltinl061297 4-35 QST Environmental


Central and St Johns) The Brookside Water Company operates two wells located east of 1-395

on the corner of Dow Road and Colonial Road approximately 4000 feet northeast of the Site

The Brookside Water Company presently services approximately 225 homes The water service

lines for the Gallup and Brookside Water Companies are interconnected allowing mixing of the

waters The Glen Acres Water Company has two wells located approximately 2200 feet west of

the Site and services approximately 36 homes The majority of the area west south and east of

the Site and some properties north of the Site rely on individual private wells for their water

supply

One school is located within a one-mile radius of the Site This is the St John Building located

approximately 5200 feet north of the Site This school served students in grades Kindergarten

through eighth grade until 1995 after which the school operates only as a pre-school This

facility is serviced by the Gallup Water Company

Nursing Homes and Elderly Housing

One nursing home and one elderly housing facility are located within one mile of the Site The

Villa Maria Convalescent Home is located approximately 5000 feet north of the Site and is

served by the Gallup Water Company Lawton House Elderly Housing Apartments is located

approximately 4800 feet north of the Site and is also served by the Gallup Water Company

Day Care Facilities

There are eight in-home child day care facilities within a one-mile radius of the Site The

operators and locations are listed on Table 4-70 Only one of these facilities is serviced by a

private supply well That facility located at 134 Lathrop Road is located approximately 3500

feet southeast (upgradient) of the Site

5797wpdoc8galluprifinaltextmasterrifnl061297 4-36 QST Environmental


50 Contaminant Fate and Transport

This section discusses the environmental fate and transport parameters associated with the

compounds detected during the Remedial Investigation Section 51 details the theoretical basis

for the evaluation of fate and transport characteristics In Section 52 Site-specific fate and

transport parameter values are presented and VOC migration rates and concentration variations

are discussed

51 Theory Migration persistence and relative distribution of compounds between air water and soil depend

on both hydrogeologic and compound-specific parameters The following discussion addresses

each of these parameters as they may affect behavior of compounds within the Study Area

511 Advection by Groundwater Flow

Within a porous medium (soil) the advection rate of dissolved or aqueous-phase compounds

under transient conditions is based on Darcys law (Bear 1979)

where

v= average pore velocity (lengthtime)

K= hydraulic conductivity (lengthtime)

i= hydraulic gradient (lengthlength or dimensionless) which equals

the piezometric head difference between two points on a

groundwater pathline divided by the distance between the two

points

n= effective or drainable porosity (volume of voidstotal soil volume)

of the soil approximately equal to the specific yield

Rj= retardation factor (R gt_ 1) a dimensionless parameter that

represents the ratio of groundwater pore velocity to the actual

advection rate in a sorbing (onto immobile soil grains) porous

medium under transient concentration conditions

5797wpdoc8glaquolluprifinaltextmasterriftil061297 5-1 QST Environmental


5111 Sorption

The retardation factor Rj represents the attenuation of a plumes frontal advancement due to

sorption ie temporary storage on soil grains Examples of analyses for which retardation

must be considered include (1) calculation of the time required for contamination to reach a given

downgradient location and (2) determination of the time required to remediate a contaminated

aquifer The retardation factor is defined by the following relationship (Freeze and Cherry

1979)

where pb is the bulk dry density of the soil (massvolume) n is the effective porosity of the soil

(volume of voidstotal soil volume) and K^ is the soil-water partition coefficient (volumemass)

often referred to as the distribution coefficient

The soil-water partition coefficient is the relative magnitude of the chemical concentration on solid

particles and in pore water for a particular soil (Lyman et al 1982)

C = AT C

where

C = concentration of the compound sorbed to the solid phase of the soil (mass

chemicalbulk dry mass soil) and

Q = concentration of the compound in the pore water of the soil (massvolume)

In this expression it is implicitly assumed that an equilibrium exists between the solid and water

phases and that the sorption process is linear (Freundlich isotherm with exponent equal to unity)

over the range of concentrations considered

For non-ionic organic compounds such as VOC Kj can be estimated from the measured fraction

of organic carbon naturally occurring in the soil fx (grams organic carbongram dry soil) and

the organic carbon sorption coefficient K^ (Tinsley 1979) as long as f^ gt_ 0001



Values of K for many common organic compounds are available in the literature K is also

related to the octanol-water partition coefficient K^ for which a large data base is also available

(eg Hansch and Leo 1979) For fine-grained soil particles K and K^ can be related as

follows (Karickhoff et al 1979)

Kx = 063

Chemical-specific relationships between K and K^ also exist for several VOC (eg Lyman et

al 1982) K values for VOC in the Study Area are presented in Table 5-1

5112 Transport by Dissolved Organic Carbon

For certain families of organic compounds the presence of dissolved organic carbon (DOC) in

groundwater can partially reverse the sorption process to soil particles and release sorbed

constituents to groundwater As a result the migration of these compounds under certain

circumstances can be enhanced (Enfield and Bengtsson 1988) Increases in mobility are greatest

for very hydrophobic (high K) compounds such as pesticides polycyclic aromatic hydrocarbons

(PAH) and dioxins Due to their characteristically low K^s VOC transport in groundwater is

generally unaffected by partitioning to DOC unless DOC concentrations exceed 10000 mgL

(Enfield and Bengtsson 1988) Typically natural DOC concentrations in groundwater range

from 1 to 10 mgL

512 Dispersion

Dispersion is a dilution process by which an initial volume of aqueous solution continually mixes

with increasing portions of the flow system Dispersion occurs on a small or microscopic scale

due to molecular diffusion in the water phase nonuniform velocity distributions within the pore

space and to a large degree the tortuous pathlines that groundwater follows during movement

through interconnected soil pores of different sizes and shapes On a macroscopic scale

dispersion results from geologic heterogeneities such as layers and lenses of contrasting soil type

(ie hydraulic conductivity) In practice dispersion is primarily due to variations in hydraulic

conductivity which produce large gradients in advective transport It is well known that aquifers

contain horizontal layers or lenses of coarser and finer grained materials compared to the average

material type that can result in zones of significantly higher and lower hydraulic conductivity

respectively than the screen interval value determined from pumping and slug tests Factor of

ten hydraulic conductivity variations or more over the thickness of an aquifer are not uncommon



(Freyberg 1986 Gelhar et al 1985 Robertson et al 1991 and Sudicky et al 1983) For

contaminant transport the more permeable zones are more important because they determine the

maximum distance over which dissolved constituents will migrate from the source area

With respect to chemical migration from a source area to an arbitrary downgradient location

dispersion will cause contaminants to arrive in a shorter time interval than the travel time based

on the mean groundwater pore velocity (Section 511) This reduced travel time associated with

dispersion is due to advection in the zones of higher hydraulic conductivity that cause the

concentration distribution in the longitudinal (flow) direction to spread out or disperse The

additional length Ld that a chemical may migrate due to dispersion can be estimated from the

following relationship (Bear 1979)

where

t = total time of groundwater travel (= VL^ laquo

Rj = retardation factor

DL = longitudinal dispersion coefficient (length 2time)

In a porous medium the longitudinal dispersion coefficient can be estimated as follows

DL =

where

v = groundwater pore velocity

aL = longitudinal dispersivity of the aquifer (length)

The percent reduction in travel time along a pathline due to longitudinal dispersion can be

calculated using the equation (Bear 1979)

where

At = reduction in travel time along a pathline due to longitudinal dispersion ()


Gallups Quarry Superfond Project - Remedial Investigation

A t = mdash- 100 ^total

Ld = additional distance (in excess of advection distance) that chemical migrates due to

longitudinal dispersion

= total distance of travel by mean advection (average groundwater flow rate)

An excellent summary of estimated longitudinal dispersivity values for numerous sites is given by

Gelhar et al (1985)

513 Advection Due to Fluid Density Differences

Advective transport can also occur due to fluid density differences in cases where the total

dissolved solids (TDS) concentration is very high A typical example is salinity intrusion into an

aquifer where the greater density of the salt water (TDS 35000000 ppb) causes it to sink within

the fresh water aquifer This causes downward advection of groundwater and results in

stratification of the aquifer into varying zones of salinity However density effects can be caused

by any dissolved compound if the concentration is high enough Laboratory experiments have

shown that density effects do not begin to be observed until the total dissolved concentration in a

plume exceeds background levels by about 1000000 to 5000000 ppb (Schincariol and

Schwartz 1990 Schwille 1988) As a result fluid density effects are not important in the Study

Area

514 Biological and Chemical Degradation

In recent years groundwater scientists have begun to understand the role of microorganisms in

the subsurface transformation of organic chemicals Recent studies have shown that large numbers of organisms can exist in the subsurface environment In many cases organic compounds can be completely degraded to harmless products However by-products can also be

produced which are more mobile and toxic than the parent compound These transformations can

make it difficult to correlate groundwater contamination with particular sources Quantitative

predictions of the fate of biologically reactive chemicals are approximate at best This is due to a

lack of understanding of the biochemical transformation process and variability of transformation

rates in an aquifer (eg as much as two orders of magnitude over a distance of less than 1 m)

For example Wood et al (1980) have demonstrated in the laboratory and observed in the field

the following anaerobic transformations of parent compounds to daughter products

5797wpdoc8galluprifinaltextmasterriftJ061297 5-5 QST Environmental


carbon tetrachloride -bull chloroform -raquo methylene chloride

trans-12-d ichloroethene

PCE -bull TCE - cis-l2-dichloroethene - vinyl chloride

11-dichloroethene

111-trichIoroethane -raquo 11-dichloroethane - chloroethane

The transformation of PCE (tetrachloroethene) and TCE (trichloroethene) to vinyl chloride is an

example of a transformation to a daughter compound which is considerably more toxic than its

parent compound

Persistence in the environment can be described by a parameter known as the environmental

half-life of a compound The environmental half-life tQ is related to a decay constant X

(Itime) in a first-order decay process

X = ln(2)tm

where ln(2) = 0693 The product of the decay constant and the porewater concentration is equal

to the rate (masstimeunit volume) at which a compound degrades into another form of

compound In practice the parameter half-life is an empirical parameter that quantifies mass loss

due to biological photochemical chemical or physical (eg volatilization) degradation

mechanisms

Within the subsurface biological activity is believed to be the principal cause of the

mineralization (ie transformation to inorganic constituents) of organic compounds (Alexander

1978) Hydrolysis is the reaction of compounds with water or the hydroxide or hydromium ions

associated with water However organic functional groups such as halogenated organics (eg

TCE TCA PCE) ketones benzenes and phenols are generally resistant to this mechanism

(Lyman et al 1982) Oxidation (loss of electrons during a chemical reaction ) and reduction

(gain of electrons during a chemical reaction) can also alter and attenuate organic compounds

For most inorganic compounds geochemical transformations are the most important degradation

mechanisms Due to the complexity of degradation processes and the fact that little data is

typically available to adequately model the loss mechanisms prediction of decay rates in the field

as discussed above is very difficult and not often feasible especially for biodegradation



515 Volatilization

The Henrys law coefficient H (Morel 1983) is an air-water partition coefficient which relates

the equilibrium concentrations in air and water for volatile compounds in a multi-phase system

such as the unsaturated zone of the subsurface or the air-water interface of a water body

H = C 1C

where C and eurobdquo are the chemical concentrations in air and water respectively The coefficient is

used in the calculation of volatilization from a water body or soil and for the determination of

solids water and air concentrations resulting from chemical partitioning in a contaminated

unsaturated soil

Organic compounds with Henrys law coefficients greater than 103 atm-m3mole are generally

considered to be highly volatile These compounds can volatilize relatively rapidly from water at

air-water interfaces such as surface water bodies or groundwater tables However the rate of

volatilization is also controlled by diffusion in the water phase Table 5-1 summarizes values of

the Henrys law coefficient for selected organic constituents detected in the Study Area

516 Aqueous Solubility

The solubility of a compound in water is the maximum amount of that compound that will

dissolve in a unit volume of pure water at a specified temperature Water solubility is one of the

most important fate and transport parameters Highly soluble compounds tend to have relatively

low KK values and Henrys law coefficients and tend to be more readily biodegradable by

microorganisms in soil Table 5-1 lists solubilities for VOC detected in the Study Area

52 Study Area-Specific Characteristics 521 Retardation Factors

A Site-specific evaluation of chemical migration rates in groundwater was conducted by

measuring the total organic carbon content TOC of 31 soil samples from the northern Study

Area (Table 5-2) The parameter f (Section 51) is equal to TOC expressed as a fraction As

discussed in Sections 26 and 2721 an ASTM method was used to measure the 4 of the 28

samples from the Former Primary Disposal Area (SB-series borings) EPA Method 9060 was

used to analyze the three samples from the boring for well MW102B The fK measurements for

the SB-series soils samples range from less than 00015 to a maximum of 0023 and the

geometric mean is 00023 In these calculations values below the detection limit of 00015 were

assigned one-half the detection limit These f^ values are typical of high hydraulic conductivity

sand and gravel aquifers

5797wpdocsgalluprifinaltextmlaquosterrifhl061297 5-7 QST Environmental


The measured values for the three MW102B samples are uncharacteristically low for coarse

stratified drift The geometric mean of these samples is 0000014 which is a factor of 100 lower

than the SB-series data The discrepancy appears to be due to the fact that EPA Method 9060 is

designed for TOC analysis of water samples The f values for the three MW102B samples are

expected to be on the order of 0001 based on comparisons with organic carbon values for

samples of a similar lithology from the Gallups Quarry and other sites Furthermore as

discussed by Karickhoff et al (1979) the available correlations that relate f^ to retardation factor

Ra are not valid below f = 0001 Below values of f = 0001 mechanisms other than

sorption to organic carbon (eg chemical adsorption to mineral surfaces) begin to dominate with

the result that overall sorption and retardation of VOC do not decrease even though the TOC

content of the aquifer materials does Therefore if f^ lt 0001 researchers have indicated that

in many cases calculations of Rd can use f^ = 0001 to account for these alternative sorption

mechanisms For these reasons the SB-series f^ data that are representative of coarse stratified

drift were used in the transport evaluations discussed in the following sections

The average f^ for the SB-series soil samples located below the water table were also calculated

to evaluate vertical trends in the data These samples include

Sample Depth (feet bgs) TOC (mgkg)

SB 104 15-17 lt1500

SB104 26-28 1700

SB108 6-8 lt1500

SB 109 4-8 1600

SB109 10-16 lt1500

SB109 17-24 1500

SB109 24-32 1600

The geometric average f for these samples is 00012 if one-half the detection limit is used for f

lt 00015 Because this average excludes shallow samples with larger silt contents it is

considered more representative of the higher hydraulic conductivity coarse-grained soils which

primarily control groundwater transport

Table 5-1 summarizes chemical-specific retardation factors for VOC detected in Study Area

groundwater These estimates are based on a f value of 00012 which as discussed above is

near the minimum value appropriate for the calculation of R Actual retardation factors in the

aquifer will be nonuniform due to the inherent variability of soil organic carbon content For

example retardation factors based on an f of 00012 may be more appropriate for evaluation of

5797wpdocsgalluprifinaltextmasterri fal061297 5-8 QST Environmental


transport rates in the middle to lower portions of the aquifer where the soil is generally coarser

and contains less silt which is associated with the organic carbon content Conversely the

average value of 00023 for all samples is likely more representative of soils in the upper portion

of the aquifer and above the water table In any case this overall variability in f^ values for the

aquifer is considered to be smaller in magnitude than the natural variability in hydraulic

conductivity values for the site The recent detailed field investigations in sand and gravel

aquifers referenced in Section 512 have shown that it is not uncommon for hydraulic

conductivities to vary by as much as a factor of ten over a scale of a few feet Variations in both

f and hydraulic conductivity values impact predicted chemical transport rates (Section 511)

A bulk dry density of 18 gcm3 and an effective porosity of 025 were estimated from the

literature based on soil grain size analyses Potential variability associated with these parameters

is small compared to k^ estimates and is not important for the following transport rate evaluation

The results in Table 5-1 are useful for comparing relative mobilities for different compounds and

assessing contaminant migration rates relative to groundwater pore velocities 11-dichloroethane

is expected to be the most mobile VOC while PCE and ethyl benzene should be the least mobile

The tracer compounds TCA and DCE are expected to migrate about a factor of two slower than

the groundwater with DCE migration being the fastest

522 Chemical Migration Rates

5221 Groundwater Travel Times

Compound-specific migration rates in the overburden aquifer were examined using Darcys law

(Section 511) to compute groundwater pore velocities from (1) measured horizontal hydraulic

gradients defined by the November 1995 piezometric surface maps (Section 332) (2) the

hydraulic conductivity data (Table 3-1) and (3) estimated retardation factors (Table 5-1) The first step was to construct a map of groundwater times-of-travel along the various pathlines shown

on the groundwater flow maps for the southern Study Area (Plate 3-9) and for the lower portion

of the aquifer in the northern Study Area (Plate 3-8) Groundwater travel times along each of the

pathlines were modelled using the Tecplot software and the interpolated piezometric head

distribution to define the continuous horizontal hydraulic gradient distribution Additional

information regarding pathline computation using Tecplot is provided in Appendix Q Since the

more permeable zones in an aquifer are known to control the rate of advancement of a plumes

leading edge (Section 512) the upper bound hydraulic conductivity estimates from Table 3-1

were considered From a review of these measurements it was determined that a mean hydraulic

conductivity of 004 centimeters per second (115 feet per day) would be reasonable to use in the

time-of-travel computations in the northern Study Area because this value is representative of the

more permeable coarse-grained soils north and northwest of the Former Primary Disposal Area

(ie wells MW102TT MW103TT MW104TT MW117TT and MW118TT) A lower

5797wpdoc8galluprifinaltextmlaquosterrifhl061297 5-9 QST Environmental


hydraulic conductivity of 00025 cms (7 ftday) representing the geometric mean value for wells

MW114TT and MW115TT was selected for the southern Study Area An effective porosity of

025 was used in the calculations

The travel-time analysis results are shown in Plate 5-1 Markers denoting half-year (northern

Study Area) and five-year (southern Study Area) travel-time intervals have been placed on each of

the pathlines to allow evaluation of spatial variations in groundwater pore velocity and

determination of total groundwater travel-time between different locations The time period

required for a particular VOC to migrate along a pathline can be estimated as the product of the

groundwater travel-time and the compound-specific retardation factor listed in Table 5-1

5222 Groundwater Flushing Rates

Another useful relationship to consider when evaluating chemical migration is the time period

required to reduce the concentration in a specific portion of an aquifer by groundwater flushing

Assuming that source material is no longer introducing contamination into the portion of the

aquifer (ie control volume) being evaluated the US EPA Batch Flushing Model (EPA 1988)

provides such a relationship

p v = J V h )

where In is the natural logarithm to the base e Rd is the retardation factor C0 is the initial or

starting average groundwater concentration in the control volume Q is the final average

concentration and Pv is the number of groundwater pore volumes which have flowed through the

control volume Pv can be estimated as

P =-raquo v Ltotal

where v is the groundwater pore velocity (Section 511) t is the time duration being considered

and L^ is the total distance or length along a characteristic pathline (from upgradient to

downgradient) through the volume of aquifer material The model assumes complete mixing of

contaminants (ie infinite dispersion) within the control volume Brusseau (1996) demonstrated

that in part due to this assumption the Batch Flushing Model can partially account for

nonequilibrium desorption (ie delayed release) of VOC from soil



For example the southern Study Area (area south of the Former Seepage Bed) can be considered a control volume with a characteristic groundwater flushing rate In this area a time t of order 10 years is required for groundwater to flow through a distance L^ of about 400 feet thus indicating an average pore velocity v of about 40 feet per year In other words one pore volume of groundwater flushes through the overburden deposits in the southern Study Area in approximately 10 years From the Batch Flushing Model it can be seen that for a nonsorbing compound with R = 1 23 pore volumes [ln(10)] would need to flush through this area to lower average concentrations by a factor of ten assuming no source material remained east of the southern Study Area or above the water table 46 pore volumes would be needed for a factor of 100 reduction Since each pore volume roughly corresponds to 10 years the factors of 10 and 100 concentration reductions would require time periods of about 23 and 46 years respectively If however one were considering a compound with R = 3 the corresponding times would be about 70 and 140 years

5223 Discussion In the northern Study Area three areas of characteristically different horizontal hydraulic gradients exist in the overburden aquifer The steepest gradients (on the order of 0025 feet per foot) are found south of the former disposal areas Assuming the hydraulic conductivity in this area is 004 cmsec Plate 5-1 shows that the groundwater travel time through this portion of the aquifer is expected to be much less than one year However hydraulic conductivity data and soil descriptions suggest that a more representative hydraulic conductivity value for the till deposits in this area would be 0001 cmsec or less which would correspond to a travel time of five years or more (eg from MW109 to the Former Primary Disposal Area)

Northeast of well MW116 north of Mill Brook and in the vicinity of the former Pervel flock plant the hydraulic gradient is about 0007 feet per foot and a hydraulic conductivity of 004 cmsec is representative of the aquifer As a result the largest groundwater pore velocities are expected to exist in these areas For example as shown in Plate 5-1 the expected groundwater travel time is about one to two years from the vicinity of Pervel to MW116 and from Pervel to MW101

Groundwater travel times downgradient from the Former Primary Disposal Area are much longer due to the low hydraulic gradients northwest of the railroad tracks In the vicinity of MW105 and MW102 the gradient is about 00003 feet per foot or more than a factor of 20 less than the gradient northeast of this area For example the estimated groundwater travel time (ignoring longitudinal dispersion) from MW107 to MW102 near the front of the VOC plume is about 8 to

10 years By comparison almost 20 years has passed since the documented disposal in the late 1970s Based on the retardation factors (Table 5-1) for TCA (R = 23) and DCE (R = 14)

5797wpdocsgalluprifinaltextmasterrifhl061297 5-11 QS7 Environmental


the estimated travel times for these compounds from MW107 to MW102 are about 20 years and

13 years respectively Considering these chemical migration rates and the fact that TCA and

DCE were detected at quantifiable levels along the VOC plume centerline and at location

MW102 it appears reasonable to conclude that these compounds are associated with the former

disposal areas

However as discussed in Section 4221 the present PCE distribution in groundwater exhibits

inconsistencies with migration from the former disposal areas Although historical detections of

PCE were found in well cluster SW17 which is located downgradient from the Former Primary

Disposal Area and near well cluster MW105 the concentrations had reduced from a maximum of

1000 ppb in 1980 to near the detection limit by early 1993 (Section 523) Based on this rate of

reduction PCE concentrations at diis location would be expected to have fallen below or near the

detection limit by 1995 In fact only trace levels were detected in wells MW105TT and

MW105T during two of the four 1995 sampling events Furthermore the measured groundwater

flow directions in the overburden aquifer indicate that many of the pathlines originating near the

former Pervel flock plant pass through the vicinity of wells MW117 MW118 MW119 MW116

MW103 MW102 and MW101 Although MW101 and MW102 are downgradient from both

Pervel and the former disposal areas groundwater flow conditions in the past would need to have

been different from present conditions for MW116 and MW103 to be downgradient from the

former disposal areas As discussed in Section 4 elevated levels of PCE TCA and DCE have

been detected in monitoring wells located on the former Pervel property Also PCE TCA and

DCE were detected in wells MW116T MW118TT and MW103TT located downgradient from

Pervel during the 1995 sampling rounds and PCE TCE and DCE were detected in well MW-C

on the former Pervel property The travel time of these compounds from Pervel to wells

MW116 MW118 MW103 MW102 and MW101 is estimated to be two to six years Taking

this into consideration along with the VOC detections in the Pervel wells during the period 1987

to 1989 (Section 523) it is possible that the low-level PCE TCA and DCE detections in

MW116T MW118TT and MW103TT represent the last remaining portion of a Pervel VOC

plume The lack of VOC detections in wells MW117 and MW119 could be explained by dilution

in these areas or by the fact that these wells may not be immediately downgradient from the

historical source area(s) on the former Pervel property

The migration rate of PCE compared to the disposal area tracer compounds TCA and DCE also

supports the existence of an off-site PCE source The expected migration rate of PCE is a factor

of two to four slower than that of TCA and DCE due to their differing K values Assuming all

of these VOC were released within a few years of each other the leading edges of the TCA and

DCE plumes should be much farther downgradient than the PCE plume Instead as evidenced by

the data shown in Plate 4-6 the opposite is true because a PCE concentration of about 30 ppb has



been detected at MW101 In terms of groundwater migration (not including retardation) from the

Former Primary Disposal Area the elevated PCE concentrations at location MW101 would

represent a total travel-time from the former disposal areas which is more than a factor of two

greater than that required for the leading edge of the TCA-DCE plume to reach MW102

Comparing the relative mobilities of PCE TCA and DCE (Table 5-1) the time required for PCE

to migrate from the Former Primary Disposal Area to well MW101 should be more than a factor

of four to eight longer than the TCADCE travel time to MW102 Based on this comparison the

PCE detections at MW101 could be attributed to transport from Pervel It is also possible that

the Pervel groundwater contamination has impacted the MW102 area Although the PCE

detections at locations MW102 and MW101 could be attributable to historical releases from the

former disposal areas the above findings (flow directions spatial PCE distribution travel times)

suggest that contamination from the former Pervel facility has at a minimum contributed to VOC

contamination (PCE and possibly DCE and TCA) at these locations

The above discussion also highlights the important issue of what defines the leading edge of the

zone of VOC contamination in the overburden aquifer Several of the above findings suggest that

the downgradient extent of VOC contamination associated with the former disposal areas is

located near wells MW102 and MW101 The convergent nature of the groundwater flow patterns

in the northern Study Area clearly establish a narrow well-defined preferred pathway of low-level

contaminant migration from the Former Primary Disposal Area The chemical analysis results

from the monitoring well sampling program confirm the measured flow directions Further

whereas TCA and DCE can presently be traced continuously along the plume centerline at

elevated levels (well locations MW107 MW105 and MW102) PCE cannot These findings

suggest that the PCE contamination in groundwater may be attributable to the former Pervel flock

plant and should not be used solely to define the leading edge of the VOC plume The time-ofshy

travel computations support the location of the disposal area VOC plume between MW102 and

MW101 The reduction of TCA and DCE concentrations to less than 10 ppb and the decrease of

xylene to below detection at MW101 is also consistent with the interpretation that the disposal

area VOC plume does not extend far beyond MW102 In addition the groundwater pore velocity

in the vicinity of wells MW102 and MW101 is estimated to be about 50 feet per year which is as

much as a factor of 20 lower than rates upgradient from this area Based on this pore velocity

and the retardation factors in Table 5-1 the migration rates of TCA and PCE are expected to be

about 20 and 10 feetyear respectively At these rates the estimated travel times for TCA and

PCE from MW102 to MW101 are about 20 and 35 years respectively As discussed in the

following section given the relatively large rates of historical VOC concentration reductions

which have been observed in the northern Study Area it is expected that PCE 12-DCE 11shy

DCE and TCE levels near MW102 will fall below MCLs within the above 20- to 35-year period

due to biodegradation and dilution mechanisms Reduction rates for vinyl chloride which also

5797wpdocsgalluprifinaltextmlaquoraquoterrifhl061297 5-13 QST Environmental


has been detected above MCLs near MW102 will likely lag behind the other VOC because it is a

final chlorinated breakdown product

523 Time-Dependent Concentration Reductions

5231 Observed Concentration Changes

Significant groundwater concentration reductions with time have been observed in the northern

Study Area from the late 1970s through the 1995 sampling rounds To illustrate these temporal

trends concentration data for selected VOC were plotted versus time to quantitatively evaluate the

reduction rates The observed rates of concentration reduction are also compared to predicted

values using the groundwater flushing relationships presented in Section 5222 and are evaluated

to determine site-specific estimates of biodegradation rates

Figures 5-1 through 5-3 contain the concentration vs time graphs for three groups of wells

organized according to transport characteristics and location Group 1 (Figure 5-1) immediately

downgradient from the former disposal areas (SW17S SW17D SW13 MW107TT MW105S

and MW105TT) Group 2 (Figure 5-2) within the downgradient portion of the VOC plume

(MW102S MW102TT MW101TT) and Group 3 (Figure 5-3) the area northeast of the VOC

plume and downgradient from the former Pervel flock plant Data from the Group 1 wells

provide a good historical perspective on improvements in groundwater quality resulting from

source removal activities in the late 1970s and from ongoing biodegradation and rainwater

infiltration (flushing) within the Former Primary Disposal Area The Group 2 wells are located

within the downgradient portion of the VOC plume and in a section of the aquifer where the

hydraulic gradient and associated groundwater transport rates are up to a factor of 20 lower than

in other parts of the northern Study Area Group 3 wells are downgradient from the former

Pervel facility where elevated levels of PCE and TCA have been detected and are located in the

portion of the aquifer with the highest groundwater flushing rates

5232 Evaluation of Concentration Reduction Rates and Mechanisms

The most important aspect of the semilogarithmic plots in Figures 5-1 to 5-3 is the characteristic

slope or trend of the concentrations as a function of time Specifically it can be seen that many

of the graphs exhibit an almost straight-line decrease in concentration with time This linear

variation is often observed with historical groundwater quality data because the linearity has a

physical basis First many biodegradation mechanisms can be modelled as a first-order decay

process (Section 51) which produces a straight-line decrease in concentrations on a semi-log plot

Second flushing of clean groundwater (eg rainwater infiltration or uncontaminated

groundwater) through a contaminated volume of aquifer material has been shown (Section

5222 Brusseau (1996)) to exhibit the same type of response In both of these approximate

first-order processes the slope of the straight-line response is inversely proportional to the



environmental half-life (Section 514) for that mechanism and a particular chemical compound

Using the relationships developed in Section 5222 the environmental half-life associated with

groundwater flushing can be defined as

Substituting the expression for pore volume Pv the flushing half-life can also be written

From the above expression it can be seen that the flushing half-life for a particular compound is

directly proportional to the chemical retardation factor and inversely proportional to the

groundwater pore velocity The groundwater flushing rate represents the rate at which

concentrations in a particular portion of the aquifer are reduced In contrast to biodegradation

groundwater flushing does not reduce the total mass of a compound in the aquifer because the

contaminants are advected to downgradient areas

In the Group 1 area historical VOC data for the SW-series wells (Metcalf amp Eddy 1993) (eg SW13 and SW17) summarized in Table 5-3 and on Figure 5-1 show that TCA TCE and PCE

levels in groundwater downgradient from the Former Primary Disposal Area have typically

decreased by a factor of more than 100 from the late 1970s to 1993 Using the SW17S data

from 1980 to 1993 the estimated environmental half-lifes for TCA TCE and PCE are

approximately 15 20 and 24 years respectively From February 1993 through the present the

shallow concentration reduction rates (SW17S and MW105S) are much higher corresponding to TCA TCE PCE and DCE environmental half-lives of about 03 lt 1 03 and 04 years

respectively Concentration reduction rates in the lower portion of the aquifer (SW17D and

MW105TT) from February 1993 through the end of 1995 are a factor of two to three slower than

shallow rates the estimated environmental half-lifes for TCA PCE and DCE in the deep aquifer are about 06 09 and 09 years respectively The higher concentration reduction rates in the

shallow aquifer may be due to rainwater infiltration andor increased biodegradation These

decreases in VOC levels are likely due to a combination of (1) source removal and source

depletion (ie soil concentration reduction by flushing mechanisms) within the former waste

disposal areas (2) mixing of rainwater infiltration with groundwater which can be a significant

dilution mechanism in the wetland areas as evidenced by the frequent occurrence of ponded water

and (3) biodegradation by microorganisms in soil

5797wpdoc8galluprifiiialtextmlaquoraquoterrifhl061297 5-15 QST Environmental


Vinyl chloride does not follow the same trends of reducing concentrations exhibited by the other

chlorinated VOC Vinyl chloride concentrations in wells MW107TT and MW105TT generally

increased during the 1995 sampling rounds Since this compound is the final chlorinated

breakdown product of PCE TCE and DCE it appears that the vinyl chloride detections are the

result of biodegradation The apparent increase in vinyl chloride concentrations and decrease in

DCE levels in well MW107TT may be further evidence that vinyl chloride detections are

associated with biodegradation mechanisms

The observed Group 1 environmental half-lifes are consistent with predicted half-lifes due to

groundwater flushing From Plate 5-1 the estimated groundwater travel time from MW107 to

MW105 is 05 to 1 year which corresponds to 1 to 2 groundwater pore volumes per year

flushing through the Group 1 Area Using the retardation factors in Table 5-1 the predicted

flushing half-lifes for DCE TCA and TCE range from 05-10 08-16 and 07-14 years

respectively and the flushing half-life for PCE is between 14 and 3 years This good agreement

between observed and predicted rates of concentration reduction downgradient from the former

disposal areas is additional evidence that source removal activities were successful and natural

mechanisms are actively producing further reductions in contaminant levels The fact that deep-

aquifer PCE and TCA concentrations near MW105 have decreased more rapidly than predicted

groundwater flushing rates during the period 1993 to 1995 suggests that biodegradation is

breaking down these parent compounds Furthermore TCA TCE and PCE reduction rates

before 1993 were much slower and are similar in magnitude to flushing rates This indicates that

biodegradation before 1993 was less important Assuming this is the case the estimated

biodegradation half-lifes for PCE and TCA for the period 1993 to 1995 range from 13-25 and

10-24 years respectively near the Former Primary Disposal Area In contrast observed

reduction rates for TCE and DCE are slower than predicted flushing rates which may be

evidence that breakdown of their respective parent compounds was significant during the period

1993 to 1995 Indeed this interpretation is consistent with the observed biodegradation of PCE

In the Group 2 area (Figure 5-2) VOC levels (with the exception of DCE) at well cluster

MW102 appear to increase in 1995 while concentrations at cluster MW101 remained relatively

constant The concentration increase at MW102 may be due to the fact that this cluster is near

the leading edge of the VOC plume and groundwater flushing rates in this area are relatively low

However as discussed in Section 522 the increased PCE and TCA levels along with daughter

products such as TCE DCE vinyl chloride and DCA may be associated with transport of the

PCE and TCA plumes on the former Pervel property

The most interesting of the Group 3 wells are wells MW-A -B and -C located on the former

Pervel property As shown on Figure 5-3 PCE and TCA concentrations in wells MW-A and

5797wpdoc8galluprifinaltextmasterrifhl061297 5-16 QampT Environmental


MW-B reduced to below detection limits by 1990 These rates of reduction correspond to halfshy

lifes of about 02 years for TCA and 03 years for PCE By comparison based on travel time

estimates from Plate 5-1 predicted groundwater flushing half-lifes for TCA and PCE

concentration reduction near Pervel are about 08 and 14 years respectively Assuming the

differences between observed concentration reduction rates and rates predicted by groundwater

flushing alone are due to biodegradation the biodegradation half-lifes for TCA and PCE are 03

and 04 years respectively In well MW-C TCA levels have reduced at a rate consistent with a

02-year half-life while the PCE half-life is approximately 05 years The corresponding

estimated biodegradation half-lifes for TCA and PCE at MW-C are 03 and 08 years

respectively Therefore biodegradation appears to be the major cause of the observed TCA and

PCE concentration reductions in the Pervel wells The lack of PCE or TCA detections in well

clusters MW119 and MW117 during the November 1995 sampling round are also consistent with

the rates of reduction in the Pervel wells For example the estimated travel times of PCE and

TCA from Pervel to the MW119 and MW117 wells are on the order of 4 and 2 years

respectively Since PCE and TCA levels in wells MW-A and MW-B were below detection by the

beginning of 1990 this groundwater with no detectable levels of either compound would be

expected to have passed through the MW119 and MW117 wells by the beginning of 1994 (PCE)

or 1992 (TCA)

In contrast the groundwater travel time from Pervel to wells MW116 MW103 and MW118 is

estimated to be up to one year longer than the travel time to MW119 and MW117 This would

correspond to increased travel times for PCE and TCA of about 4 and 25 years respectively

Based on these estimates low but detectable levels of PCE and TCA would be expected in wells

MW116 MW103 and MW118 during 1995 groundwater sampling In fact PCE TCA and

DCE were detected at each of these locations in 1995 at trace levels Slightly higher

concentrations of PCE and TCA were detected in MW116T during January 1995 but trace levels

were detected during each of the three subsequent 1995 rounds Further these rates of PCE and

TCA migration from Pervel would be consistent with the detections in well clusters MW102 and

MW101

Additional estimates of biodegradation rates were made by evaluating concentration reductions

within the parcel of groundwater located near well SW17 in 1980 Using the travel times shown

in Plate 5-1 it is estimated that about five years would be required for groundwater to travel from

SW17 to MW102 The corresponding chemical migration rates for TCA TCE and PCE are 12

11 and 20 years respectively Due to longitudinal dispersion (Section 512) the actual travel

times would be somewhat less Therefore groundwater presently in the MW102 area is expected

to be representative of historical (1980) groundwater contamination from the SW17 area

Neglecting possible contaminant contributions from Pervel most of the VOC concentration

5797wpdocsglaquolluprifinaltextmalaquoteiTifTil061297 5-17 QST Environmental


reductions occurring in this parcel of groundwater as it traveled from SW17 to MW102 would be

due to biodegradation and rainwater infiltration

Figure 5-4 shows the TCA TCE and PCE concentration data from 1980 and 1982 for SW17S

and from January and November 1995 for wells MW102S and MW102TT The slopes of the

lines connecting the data from these two periods provide estimates of the combined biodegradation

and rainwater dilution rates for these compounds The combined half-lives for these two

mechanisms are 15 years (TCA) 18 years (TCE) and 21 years (PCE) From Bear (1979) the

half-life for rainwater dilution can be estimated as

n - b

where n = effective porosity b = saturated thickness and I = groundwater recharge rate due to

rainwater infiltration Using n = 025 b = 60 feet and I = 30 inchesyear (USGS 1995) the

half-life for dilution due to rainwater infiltration is about 4 years Using this value the estimated

biodegradation rates for TCA TCE and PCE within the VOC plume are 24 33 and 44 years

respectively These estimated biodegradation rates for TCA and PCE are a factor of two to three

less than estimated rates near the Former Primary Disposal Area during the period 1993 to 1995

5233 Summary

From the late 1970s through the four 1995 sampling rounds groundwater concentrations in the

VOC plume downgradient from the Former Primary Disposal Area have decreased at a rapid rate

The groundwater quality data from 1995 indicates that this trend of reducing concentrations is

continuing Based on these concentration reduction rates most VOC levels will fall below their

respective MCLs in a period of less than four years Vinyl chloride is an exception to this trend

because increased levels of this compound were detected in 1995 apparently due to the chemical

break down of its parent compounds PCE TCE and DCE

Analyses of these concentration reductions with time indicate that biodegradation and dilution by

rainwater infiltration are the key mechanisms responsible for these changes with biodegradation

likely the most important component Within the VOC plume biodegradation and rainwater

infiltration are reducing most VOC (with the exception of vinyl chloride) concentrations by about

a factor of two every two years which corresponds to an environmental half-life of two years

5797wpdocsglaquolluprifinaltextmraquosterrifnl061297 5-18 QST Environmental


60 Summary and Conclusions

This section provides the conceptual model developed for the Study Area based on the findings

of the Phase 1A and IB field investigations and the results of the Long-Term Monitoring

Program sampling events

61 Conceptual Model of the Study Area The conceptual model was developed from the collection and analyses of information and data

from the Remedial Investigation (RI) as well as historical information and data A conceptual

model is an overview of the Study Area taking into account all media and their interrelationships

and describes in summary fashion Site conditions as they pertain to contaminant sources and

migration pathways This conceptual model will be used to support the evaluation of potential

remedial alternatives for the Feasibility Study

611 Geology

Geologic data collected during the RI indicate the following

bull Significant surficial or overburden deposits encountered in the Study Area are till

and glacial deposits referred to as stratified drift

bull The till is relatively dense and is comprised of a fine sandy matrix with abundant

gravel cobbles and boulders The till was encountered directly above bedrock at

most locations at thicknesses of 10 to 20 feet with the thickest accumulations

located along the topographic (bedrock) high in the central area of the Site

bull The stratified drift typically overlies the till or bedrock and consists of poorly to

well sorted deposits of gravel sand and silt Grain size analyses indicate that the

stratified drift is primarily comprised of fine to coarse sands with lesser amounts

of silt and fine gravel The stratified drift thickness varies from less than a few

feet in upland areas to as much as 70 feet in the vicinity of Mill Brook

bull Bedrock within the Study Area consists of grey fine- to medium-grained gneiss

with varying contents of amphibolite biotite and hornblende The bedrock

surface is characterized by a large slope and dips to the northwest and west-

southwest from a bedrock high located about 400 feet southeast of the Former

Seepage Bed The total bedrock surface relief in the Study Area approaches 100

feet

5797wpdocsgalluprifinaltejctmasterri fhl061297 6-1 QfT Environmental


bull Geophysical investigations (seismic refraction and magnetometer surveys)

conducted in the vicinity of the Former Seepage Bed did not reveal evidence of

one or two suspected discrete bedrock faults Rather the bedrock in the central

portion of the Site may be more accurately characterized as a series of

interconnected (to varying degrees) fractures and faults

^

612 Hydrogeology

Data regarding hydrogeologic conditions are summarized as follows

Hydraulic Conductivity

bull Across the Study Area test results indicate that the hydraulic conductivity

of the shallow overburden deposits averages approximately 0001

centimeters per second (cms) while the mean hydraulic conductivity for

the deep portion of the aquifer is about 0005 cmsec A mean hydraulic

conductivity of about 0037 cms is more representative of coarser-grained

deposits in the middle to lower portions of the overburden aquifer

northwest of the railroad tracks where the saturated thickness increases to

almost 70 feet

bull The mean hydraulic conductivity of the till (000047 cms) is a factor of

ten less than the average for the stratified drift deposits in the lower

portion of the aquifer and varies between 00002 and 0002 cms

Although the hydraulic conductivity of the till indicates that it is less

permeable and hydrogeologically distinct from the overlying stratified drift

deposits the hydraulic conductivity contrast is not large enough to

significantly alter groundwater flow directions or rates

cir

bull The mean bedrock hydraulic conductivity (000018 cms) is a factor of 25

lower than the average for the coarse-grained stratified drift Due to the

heterogeneous nature of fracture sizes and interconnectivity and their

associated nonlinear effect on groundwater flow rates the hydraulic

conductivity of the bedrock can be expected to be highly variable

throughout the Study Area



Groundwater Flow

bull The overburden aquifer is the preferred pathway for groundwater transport

of dissolved constituents This conclusion is supported by the hydraulic

conductivity test results and observations that an upward groundwater

flow component from bedrock to overburden exists throughout most of the

Study Area VOC detections in bedrock wells are believed to be caused

by vertical dispersion in the upper portion of the fractured bedrock

bull Because the unconsolidated deposits become unsaturated in the vicinity of

the Former Seepage Bed discussions of groundwater flow in overburden

are naturally divided into northern and southern portions of the Study

Area

bull Overburden groundwater flow south of the Former Seepage Bed is

generally from east to west at an average hydraulic gradient of 001 feet

per foot (vertical change in piezometric head per horizontal distance) and

is strongly influenced by the bedrock surface and drainage to the wetlands

and stream west of the railroad tracks The saturated thickness in this

area increases from zero near the bedrock high (northeast corner) to more

than 60 feet near the railroad tracks

bull Three distinct zones of overburden groundwater flow exist in the northern

Study Area In the area between the Former Primary and Secondary

Disposal Area and the Former Seepage Bed groundwater flow is largely

through till deposits and toward the north-northwest The hydraulic

gradient in this area is steep (about 003 feet per foot) and strongly

influenced by the dip of the bedrock surface and the lower hydraulic

conductivity of the till deposits The saturated thickness increases from

zero south of MW109 to 20 to 30 feet near the former disposal areas

North-northwest of these areas the hydraulic gradient lessens significantly

to a range of 00003 to 00007 feet per foot (factor of 40 to 100

reduction) North and northeast of Mill Brook the hydraulic gradient is

about 0007 feet per foot

bull Available data indicate that in the northern Study Area overburden

groundwater flow north-northwest of the Former Primary and Secondary

Disposal Areas exhibits a strongly convergent pattern The flow

5797wpdocsgalluprifinaltextmlaquosterriftU061297 6-3 QST Environmental


converges from the east-northeast and southwest toward a centerline

generally defined in the downgradient direction by wells MW105

MW102 and MW101 Groundwater flows along this centerline from the

former disposal areas to the northwest Groundwater also flows from the

vicinity of the former Pervel flock plant in southwesterly and westerly

directions toward wells MW116 MW103 and MW101

South of the Former Seepage Bed groundwater flow within the upper

portion of the bedrock unit is primarily in a westerly direction In the

northern Study Area the predominant bedrock flow component is toward

the northwest In both areas the hydraulic gradient is relatively steep and

averages about 002 feet per foot Groundwater flow in bedrock near the

Former Seepage Bed is toward the northwest in the direction of wells

MW113 and MW106 and exhibits no apparent influence from locally

increased fracturing identified from the geophysical investigation and the

hydraulic testing in well MW11 IB

Vertical flow of groundwater is important in the upper several feet of the

bedrock unit Groundwater flow was found to be discharging from

bedrock to overburden at all locations during each of the measurement

dates with the exception of MW109 At MW109 the saturated overburden

thickness is less than a few feet and MW109 is located over a much

higher bedrock elevation than all other wells at which vertical flow from

bedrock was measured

Vertical flow in the overburden aquifer is of increased importance in two

areas in the vicinity of the Former Primary Disposal Area (wells clusters

MW107 MW108 and MW116) where vertical flow directions are

downward and within the upper portion of the aquifer near Mill Brook

where vertical flow is upward

Stream piezometer data and groundwater flow modeling indicate that Mill

Brook generally gains water from the overburden aquifer in the northern

portion of the Study Area

5797wpdoc8galluprifinaltextmraquosterrifhl061297 6-4 Q5T Environmental

Gallups Quarry SuperfimdProject - Remedial Investigation


6131 Contaminant Source Investigation

The following summarizes the findings of contaminant source investigations during the RI

bull Previous remedial activities have completely removed the waste materials

(intact drums and bulk liquid waste) from the Site

bull The Former Seepage Bed and the Former Secondary Disposal Area

contain little residual contamination from the disposal activities which

occurred in the late 1970s

bull Residual levels of contamination primarily VOC and PCB were detected

in the Former Primary Disposal area In general the highest levels of

VOC are located at or just below the groundwater table in native soils

immediately beneath the fill materials and diminish rapidly with depth

PCB were detected primarily within fill materials

bull Other than the three known former disposal areas and the remains of the

former CTDOT asphalt plant no other significant disposal areas were

found to exist on the Site

6132 Groundwater Quality

Groundwater quality data collected during the Phase 1A program indicate the following

bull No significant groundwater contamination was detected within the

overburden or bedrock units in either the southern Study Area or in the

vicinity of the Former Seepage Bed

bull In the northern Study Area a narrow low to moderate-concentration

VOC plume (primarily TCA and DCE) was detected in the overburden

aquifer extending from the Former Primary Disposal Area to the

northwest towards Mill Brook

bull Comparison of present concentrations with historical data indicate that

concentrations within the VOC plume are significantly decreasing with

time From 1978 through 1995 TCA TCE and PCE concentrations

have decreased on the average by more than a factor of two every two

5797wpdocsgalluprifinaltextnui8terrifhl061297 6-5 QSTEnvironmental


years This trend appears to have continued through the four 1995

sampling rounds for these as well as other VOC with the exception of

the break down product vinyl chloride Biodegradation and dilution by

rainwater infiltration have been identified as the primary mechanisms

causing the concentration reductions with biodegradation the most

important component

The size and orientation of the VOC plume are in excellent agreement

with the established groundwater flow directions

Available information indicates that the leading edge of the VOC plume

associated with the Former Primary Disposal Area is located between

monitoring well clusters MW102 and MW101 VOC transport rates and

the reduction of TCA and DCE levels to estimated values at MW101

support this conclusion

PCE detections in the downgradient portion of the plume exhibit

inconsistencies with migration from the Site Groundwater pathlines and

time-of-travel estimates indicate that the PCE may be attributable to

contaminant transport from the former Pervel facility located north of the

Site Specifically it is possible that PCE detections at locations MW118

MW116 MW103 MW102 and MW101 may have resulted from

groundwater transport from the vicinity of the former Pervel flock plant

However it is also plausible that the PCE detections at locations MW102

and MW101 are attributable to the former disposal areas

Results of surface watersediment sampling and analyses stream

piezometer measurements and groundwater flow modeling indicate that

some discharge of the shallow portion of the plume into Mill Brook is

occurring There are low-level detections of VOC in the section of brook

intersecting the plume however the concentrations are well below those

reported to cause adverse effects in wildlife Detections downstream

adjacent to the municipal sewage treatment plant and below the confluence

of Fry Brook and Mill Brook are probably attributable to off-site sources

along Fry Brook north of the Study Area

Only one of the bedrock wells (MW105B) indicated elevated levels of

VOC Trace levels of a limited number of VOC were also detected in

5797wpdocsgalluprifinaltextma8terrifhl061297 6-6 QStf Environmental


MW102B MW107B MW108B and SW-10 however bedrock is not a

preferred pathway for contaminant migration due to its characteristically

low hydraulic conductivity and the consistent upward component of

ground water flow from bedrock to overburden which exists throughout the

Study Area

5797wpdocsgalluprifinaltextmastemfiil061297 6-7 QSTEnvironmental


70 References

Alexander M 1978 Biodegradation of Toxic Chemicals in Water and Soil in Proc 176th

National Meeting Miami Beach FL Sept 10-15 v 93 American Chemical

SocietyDivision of Environmental Chemistry

Amtec Engineering 1994 Tecplot Version 6 Belevue WA

Bear J 1979 Hydraulics of Groundwater McGraw-Hill

Beyer WN 1990 Evaluating Soil Contamination US Fish Wildl Serv Biol Rep 90(2) 25

pp July 1990

Bouwer H and Rice RC 1976 A Slug Test Method for Determining Hydraulic Conductivity

of Unconfined Aquifers with Completely or Partially Penetrating Wells Water Resources

Research vol 12 no 3 pp 423-428

Boynton GR and Smith CW 1965 Aeromagnetic map of the Plainfield quadrangle New

London and Windham counties Connecticut US Geological Survey Geophysical

Investigations Map GP-541 scale 124000

Brusseau ML 1996 Evaluation of Simple Methods for Estimating Contaminant Removal by

Flushing Groundwater V 34 No 1 pp 19-22

CTDEP 1986 Water Quality Classification Map for the Thames Southeast Coast and Pawcatuck River Basins Sheet 2 of 2 CTDEP Water Compliance Unit Hartford

Connecticut

Dixon HR 1965 Bedrock geologic map of the Plainfield quadrangle Windham and New

London Counties Connecticut US Geological Survey Geologic Quadrangle Map GQshy

481 scale 124000

Enfield CG and Bengtsson G 1988 Macromolecular Transport of Hydrophobic

Contaminants in Aqueous Environment Groundwater v 26 no 1 pp 64-70

ERT 1988 Preliminary Hazardous Waste and Petroleum Hydrocarbon Contamination Evaluation

of the InterRoyal Property Plainfield CT



ESE 1994 Gallups Quarry Superfund Project RIFS Work Plan Phase 1A (Prepared by Haley

amp Aldnch Inc Finalized by ESE)

ESE 1995 Initial Site Characterization Report March 1 1996

ESE 1995a April 1995 Long-Term Monitoring Report July 28 1995

ESE 1995b July 1995 Long-Term Monitoring Report October 27 1995

ESE 1996a Long-Term Monitoring Program - Data Report February 1996 Sampling Event

June 19 1996

ESE1996b Long-Term Monitoring Program - Data Report May 1996 Sampling Event

September 24 1996

ESE 1996c Long-Term Monitoring Program - Data Report August 1996 Sampling Event

December 18 1996

ESE 1997a Long-Term Monitoring Program - Data Report November 1996 Sampling Event

March 31 1997

ESE 1997b Long-Term Monitoring Program - Data Report February 1997 Sampling Event

May 21 1997

Fitchko J 1989 Criteria for Contaminated SoilSediment Cleanup Pudvan Publishing

Company Northbrook IL

Freeze RA and Cherry JA 1979 Groundwater Prentice-Hall Inc Englewood Cliffs

New Jersey

Freyberg DL 1986 A Natural Gradient Experiment on Solute Transport in a Sand Aquifer 2

Spatial Moments and the Advection and Dispersion of Nonreactive Tracers Water

Resources Research Vol 22 pp 2031-2046

Fuss and ONeill Inc 1979 Evaluation of a chemical waste disposal area Tarbox Road site

Plainfield Connecticut January 1979



Gelhar LW Montogluo A Welty C Rehfeldt KE 1985 A Review of Field-Scale

Physical Solute Transport Processes in Saturated and Unsaturated Porous Media Electric

Power Research Institute Report No EA-4190

Geraghty amp Miller Inc 1989 Aqtesolv Aquifer Test Solver Version 11 Reston VA October

1979

Hansch C and AJ Leo 1979 Substituent Constants for Correlations Analysis in Chemistry

and Biology John Wiley amp Sons New York

Hem JD 1989 Study and Interpretation of the Chemical Characteristics of Natural Water (3rd

Edition) USGS Water-Supply Paper 2254 US Government Printing Office

Washington DC

HRP Associates Inc 1993 Addendum to Groundwater Monitoring Report Former Pervel

Industries Flocking Plant March and June 1993 Sampling Events HRP Associates

Inc Plainville Connecticut

Karickhoff SW DS Brown and TA Scott 1979 Sorption of Hydrophobic Pollutants on

Natural Sediments Water Research Vol 13 pp 241-248

Lyman WJ Reehl WF Rosenblatt DH 1982 Handbook of Chemical Property

Estimation Methods-Environmental Behavior of Organic Compounds McGraw-Hill

Metcalf amp Eddy 1993 Final Data Summary Report START Initiative Gallups Quarry Plainfield Connecticut

Morel MM 1983 Principles of Aquatic Chemistry John Wiley amp Sons

Prior T Eaton L and Sperduto M 1995 Habitat Characterization for Gallups Quarry

Superfund Site Plainfield Connecticut United States Department of Interior Fish and

Wildlife Service New England Field Offices Concord NH

Reed PB 1988 National List of Plant Species That Occur in Wetlands Connecticut US Fish

amp Wildlife Service Washington DC NERC-881807 105p

Robertson WD Cherry JA Sudicky EA 1991 Groundwater Contamination from Two

Small Septic Systems on Sand Aquifers Groundwater v 29 no 1 pp 82-92


Gallups Quarry SuperJUnd Project - Remedial Investigation

Schincariol RA and Schwartz FW 1990 An Experimental Investigation of Variable Density

flow and Mixing in Homogeneous and Heterogeneous Media Water Resources Research

v26 no 10 pp2317-2329

Schwille F 1988 Dense Chlorinated Solvents in Porous and Fractured Media translated from

German and Edited by JF Pankow Lewis Publishers Chelsea Michigan

Shacklette HT and Boerngen JC 1984 Element Concentrations in Soils and Other Surficial

Materials in Conterminous United States USGS Professional Paper 1270 US

Government Printing Office Washington DC

Sudicky EA Cherry JA and Frind EO 1983 Migration of Contaminants in Groundwater

at a Landfill A Case Study 4 A Natural Gradient Dispersion Test J Hydrology v 63

pp 81-108

US EPA 1986 Quality Criteria for Water Office of Water Regulations and Standards

Washington DC USEPA 4405-86-001 (NTIS PB87-226759)

US EPA 1987 A Compendium of Superfund Field Operations Methods US EPA540Pshy

87001 (NTIS No PB88-181557)

US EPA 1988 Interim Final Guidance on Remedial Actions for Contaminated Groundwater at

Superfund Sites US EPA Washington DC

US Fish and Wildlife Service 1995 Habitat Characterization for Gallups Quarry Superfund

Site Plainfield CT Concord NH 16 p

USGS 1993 Geohydrology of the Gallups Quarry Area Plainfield CT

5797wpdocsglaquolluprifinaltextmasterrifhl061297 7-4 QST Environmental

SOURCE PLAINFIELD75 MINUTE

124000

0 A 2

SCALE IN MILES

OONNECnCPT

OlMDIMNGLE LOCATION

CONNECTICUT QUADRANGLE USGS TOPOGRAPHIC MAP SERIES 1983


(603) 689-3737

GALLUPS QUARRY SUPERFUND PROJECT PLAINFIELD CONNECTICUT


FIGURE 1-1

SITE LOCATION MAP DRAWING NAME 1LOCDWG miE NUMBER 7194-138

SCALE AS SHOW [REVISION 0 I DRAWN BY PAD IPATE gg97

N

500 0 500

SCALE IN FEET

LOT NUMBER OWNER

1 C STANTON GALLUP 2 KENNETH R MOFFITT 3 INTERMARK FABRIC CORP 4 NORMAN ATLAS 5 FREDERICK BARRETT 6 WILLIAM ROPERANNE OWENS 7 ROBERT GLUCK

TILCON MINERALS INC 9 TOWN OF PLAINFIELD 10 ROBERT GLUCK 1 1 STANTON GALLUP 12 - 15 EDWARD DUNCAN 16 ELAINE M NILSON 17 ADOLPH SHAGZDA 18 ANTHONY FATONEJOSEPH FATONE 19 NANCY LAMIRANDE 20 KENNETH R MOFFITT 21 CONNECTICUT DOT 22 ST JOHNS CHURCH 23 DOROTHY CARON 24 ALFRED AND EVELIN RIENDEAU 25 PAUL GELINAS AND JOAN BURNORE 26 ALBERT SR AND ANN WILCOX

LEGEND

D LOT NUMBER

-- WATERCOURSE GALLUPS QUARRY SITE

PROPERTY BOUNDARY

NOTES

BASE PLAN PROVIDED BY USEPA DRAWING NO 707600 DATED 14 OCTOBER 1993




(603) 889-3737



FIGURE 1-2 1000

PROPERTY BOUNDARIES AND ADJACENT LANDOWNERS

DRAWING NAM^ PROPBNDDWG |^LE NUMBER 7194 138 SCALE AS SHOW^REVISION 0 |pRAWN BY PAD loATE 5997

GB

N

LEGEND

WATERCOURSE

TO PACKERS POND (CUSS CBc)

APPROX 1 MILE WEST OF SITE

PROPERTY

CLASS Be

BOUNDARY

SURFACE WATER

CLASS BA SURFACE WATER

CLASS GE GROUNDWATER

CLASS GEGA GROUNDWATER

NOTES

1 BASE PLAN PROVIDED BY USEPADATED 14 OCTOBER 1993

DRAWING NO 707600

2 HORIZONTAL DATUM shy CONNECTICUT STATE PLANSYSTEM NORTH AMERICAN

COORDINATE DATUM OF 1927

3 PROPERTY BOUNDARIES OBTAINED FROMPLAINFIELD TAX ASSESSORS OFFICE

TOWN OF

4 UNLESS OTHERWISE INDICATEDCLASSIFICATION IS GA

CONNECTICUT GROUNDWATER

410 Amherst Street Nashua MH 030G3

(603) 889-3737



500 0

SCALE IN

500

FEET

1000 FIGURE 1-3

CONNECTICUT SURFACE AND GROUNDWATER CLASSIFICATION ZONES

DRAWING NAME SOILTYPEDWG

SCALE AS SfcWN [RFVISION 0 l o R A W N B Y D-fB FILE NUMBER 7194 138

G1097

LEGEND

WATERCOURSE

PROPERTY BOUNDARY

LOCATION OF PREVIOUSLY INSTALLED MONITORING WELL

NOTES


2 HORIZONTAL DATUM shy CONNECTICUT STATE PLAN COORDINATE SYSTEM NORTH AMERICAN DATUM OF 1927



(603) 869-3737


- REMEDIAL INVESTIGATION REPORT

500 0 500 1000 FIGURE 1-4

GROUNDWATER MONITOR WELLS INSTALLED BY SCALE IN FEET FUSS amp ONEILL IN 1978 AND USGS IN 1993

DRAWING NAME SWMAGDWG FILE NUMBER 7194 138

SCALE A3 SHQHW [REVISION 0 [DRAWN BY DJB |DATE 51097

bull- - n V i _raquo-A raquoraquobull bull Jpoundi _


124000 410 Amber atNashua NH

Street 03063

(603) 889-3737


SCALE IN MILES PLAINFIELD CONNECTICUT REMEDIAL INVESTIGATION REPORT

FIGURE 1-5 COHNgOICOT

SITE LOCATION MAP AND NEARBY INDUSTRIAL PROPERTIES

QURANGLE LOCATION NAME LOCMAPXXDWG FILE NUMBER 7194138

SCALE AS SHOWN [REVISION 0 I DRAWN BY CBG loATE 5997

1450

FIGURE 3-1 GROUNDWATER ELEVATIONS MW-101

1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-101S MW-101TT MW-1 01 T


1450shy

OJ 2

LLJ 1445shy

O CO

1440shyMW-102B WAS NOT INSTALLED UNTIL PHASE IB

1435

LLJ _l HI DC LJJ

I QZ

O cc CD

1430shy

1425shy

1420 010195

1 041195

1 072095

1 102895 020596

I 051596

I 082396

1 120196

1 031197 061997

DATE

MW-102S MW-102TT ---pound-- MW-102B


1450

CO

LLJ 1445shy

O CO lt |mdash 1440shy

lt 1435shy

LLJ _J LLJ

CC LLJ 1430shy

I Q Z D O CC C5

1425

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-104S MW-104TT


1450

CO2 LLJ 1445shy

O CO

1440shy

1435shy

LLI

LU tr QJ 1430shy

I Q

D O cc O

1425shy

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-105S MW-105TT MW-105T -X- MW-105B

1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-106S MW-106TT

1450


1415 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-103S MW-103TT


1490

CO

x- -X

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-107S MW-107TT MW-107T -Xshy MW-107B


1465shy

(02 LU

1460shy

O CO

1455shy

1450shy

LU

LU

CC LU

lt

1445shy

1440shy

Q

mdashJocc O

14j vshy^

1430 010195

1 041195

1

072095 1

102895 T T

020596 051596

DATE 082396

1 120196 031197 061997

MW-1083 MW-1 08TT MW-1 08B

1580


(0 1575shy

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-109S MW-109B

1470

FIGURE 3-10 GROUNDWATER ELEVATIONS MW-110S

1450 i 1 i i i 1 r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-110S

1610

FIGURE 3-11 GROUNDWATER ELEVATIONS MW-111B

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-111B

1590


lt) 1580shy

149 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-1123 MW-112T MW-112B


1510shy

2UJ

O m lt

1500shy

1490shy

1480shy

LU _l LJJ

CC LU

1470shy

1460shy

Q

OCC O

145degH

1440 010195 041195 072095

1 102895 020596 051596

DATE 082396

1 120196

1 031197 061997

MW-113S MW-113B

1580


1460 i r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-114S MW-114TT

150


1465 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-115S MW-115TT --pound-- MW-115B

1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-116S MW-116T


1480shy

CO

LJJ gto CD

1475shy

1470shy

LU LU

CC LU

1465shy

WELLS AT THIS LOCATION WERE NOT INSTALLED UNTIL PHASE 1B

O z D O CC (5

1460shy

1455 010195

1 041195 072095

I 102895

1 1020596 051596

DATE

1 082396 120196 031197 061997

MW-117S MW-117TT


1465shy

LU 1440shy

LLJ

CC LU 1435shy WELLS AT THIS LOCATION WERE

I Q Z D O CC CD

1430shy

1425shy

NOT INSTALLED UNTIL PHASE 1B

1420 010195

1 041195

I 072095

1 102895 020596

1 051596

DATE 082396 120196 031197 061997

MW-118S MW-118TT


1475shy

CO2 LJJ

1470shy

o m

1465shy

1460shy

UJ_i UJ cc LJJ

1455

1450shy


Q Z

O cc O

1445shy

1440 010195 041195

1 072095

I102895

I I 020596 051596

DATE

1 082396

i 1 201 96 031 1 97 061 997

MW-119S MW-119TT

1455

FIGURE 3-20 GROUNDWATER ELEVATIONS SW-3SD

1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

SW-3S SW-3D

Originals in color

VERTICAL

PROJECTED FOOTPRINT of FORMER PRIMARY

DISPOSAL AREA

MILL BROOK

NOTES (1)

(2)(3)

THE SAME CONTOUR INTERVALS ARE USED FOR THE SHALLOW AND DEEP MAPS

WATER LEVEL DATA COLLECTED 2-2-95 VERTICAL EXAGGERATION = 10X

410 Amherst Street THIS FIGURE SHOWS ONLY THE PREDOMINANT OVERBURDEN GROUNDWATER FLOW PATHWAYS WHICH ORIGINATE Nashua NH 03063 IN THE VICINTY OF THE FORMER PRIMARY DISPOSAL AREA AS VIEWED FROM THE EAST (603) 889-3737

ALTHOUGH THIS DEPICTION IS BAStU ON PlEZOMETRlC HEAD OAiA (MEASURED ON FEBRUARY 2 1335) THIS FiGURE DOES NOT SHOW EVERY POSSIBLE FLOW PATHWAY WITHIN THE OVERBURDEN AQUIFER THE UPPER SURFACE REPRESENTS THE SURFACE OF THE WATER TABLE THE LOWER SURFACE REPRESENTS GALLUPS QUARRY SUPERFUND SITE A PLANE DEFINED BY THE PIEZOMETRIC HEAD AS MEASURED IN WELLS WHICH ARE SCREENED IN THE LOWER PORTION OF THE OVERBURDEN AQUIFER THE LOWER PLANE DOES NOT REPRESENT THE LOWER BOUNDARY OF THE OVERBURDEN AQUIFER AND NEITHER PLANE IS GEOLOGICALLY SPECIFIC PLAINFIELD CONNECTICUT


FIGURE 3-21

PREDOMINANT OVERBURDEN GROUNDWATER FLOW PATHWAYS IN NORTHERN PORTION OF STUDY AREA

DRAWING NAME FLOWPATHDWG IFILE NUMBER 7194 138

SCALE NT5 JREVSION 1 JDRAWN BY CBG [DATE 6-9-97~

lt 4 Original includes color coding

10s r SW-17SandMW105S Ho5 SW-17D and MW105TT

P 1 V |

1deg4 i

4 mI U 5 k 4 3

i i f J |103 1I Un |

|io2 bull m2

bull I U = i ii gtv o r

BDL mdasha I bullM BDL a i i c CM ltD 0 ltj at agt c c at at T c I 1 I i i i

SW-13 c MW105S I10s pound

1I Un =

m4

104 I U sect

J 1I 3 bull PCE -m

H103| IU sect bull TCA

2 ^ TCE 102

m

I bull 1 2-DCE A i 1

T VINYL CHLORIDE 1 0 ^h

bull A1

10deg BDL = BELOW DETECTION LIMIT 10deg 1 U = V 3 X

=

ni-M ^ ^ ^ laquote BDL 0 V o0 CV tfi _ CO CXgt o0 ogt ogt 2 C oraquo oraquo cn O) O lt C

i- r- -3 4 1 1995

MW105TT MW107TT 105 105

E pound

i shy104

2 = 104 I = ^^to^f^P 410 Araherst Street bull^OJfcCfe Nashua NH 03063 103 103 ^raquo^^^j^ (603) 889-3737 f bull 1

- T T T shy ~ A102 i1 bull bull S 102

GALLUPS QUARR y SUPERFUND SITE I 1

PLAINFIELD CONNECTICUT REMEDIAL INVEi iTIGATOJV REPORT 10 101

i 1 FIGU RE 5 110deg i = 10deg

BDL laquo BDL VOC CONCENTRATION CHANGES VERSUS TIME M

^ i DOWNGRADIENT FROM FORt ilER PRIMARY DISPOSAL AREA sect o ^ O

^

-5lt 5amp -s= z1

1995 1995

Original includes color coding

CO

NC

ENTR

ATIO

N (

ppb)

IU sect MW102S

s 105 MW102TT

104 1 i 104

103 1 103

102 I I A sect 102

1

A

T

1 101

10deg i 10deg

nni BDL +shytr a O o

1995 1995

bull PCE

bull TCA A TCE

bull 12-DCE

T VINYL CHLORIDE

MW101TT 105

104

103

102

10deg

BDL

1995

410 Amhersl Street Nashua NH 03063

(603) 889-3737



FIGURE 5-2

VOC CONCENTRATION CHANGES VERSUS TIME DOWNGRADIENT PORTION OF PLUME

BDL = BELOW DETECTION LIMIT

s

104 tmdash a IU I

1 IU103 U-o 1F= E

i 105 to2 tmdash r 1 1deg1 i~ deg 10degL

BDL Emdash oS

105 i

104 i

103 i

102 bull

101 1

10deg

BDL 0S

105 9

104 B

103 I

102 i

101

10deg 1

BDL OCOogt

^ 00 ogt

^ra lt cltJgt

C O 0 0

0gt

MW-A

4 bull

1 1 1

co 01

MW-B

_J 1 1

1

i CO

8)

MW-C

11 1

lt lt

CO CO ogt

bullbull

laquoftr i i bull i

mn

Tbull1

bullbull

bull i

9

bull

bullM bullM bullbull- 1

egt lt t a) a

aai Tshy^

WM cN gjcI) lt J1

bull 1

bull 11 1

MM bullMl bullfr- 1

c4 0aigt C

t bullgt araquo lt raquo

T ^


10 |

-iM 10 s

-irvS 10 |

nn2 10

bullm1 bull

1UJ

oni AZs

^^^f

MW116T

A a

A =J =3

1995

bull

bullA

PCE

TCA

TCE

1 2-DCE

sect

1

s

I I 1

A gti

T VINYL CHLORIDE


410 Amherst Street bull^OJUV^ Nashua NH 03063 ^raquo^^ ^jj^ (603) 889 3737

nmranmini x

GALLOPS QlARRy SUPERFUND SITE PLAINFIELD CONNECTICUT


FIGURE 5-3

VOC CONCENTRATION CHANGES VERSUS TIME AREA NORTH-NORTHEAST OF PLUME

I Original includes color coding

SW-17S MW102S and MW102TT


bull PCE (603) 889-3737

bull TCA A GALLUPS QUARRY SUPERFUND SITE TCE

PLAINFIELD CONNECTICUT REMEDIAL INVESTIGATION REPORT


FIGURE 5-4

EVALUATION OF BIODEGRADAT10N AND RAINWATER DILUTION RATES IN VOC PLUME

(D NOTE FORWELLS MW102S and MW102TT ONLY JANUARY and NOVEMBER 1995 DATA ARE PLOTTED

GENERAL

Volume 1

Volume 2

Volume 3

Volume 4

Volume 5

Volume 6

Volume 7


TABLE OF CONTENTS

Text and Figures

Tables

Plates

Appendices A B C D E Famp G

Appendices H I J amp K

Appendices L M amp N

Appendices O P Q R S T U amp V

5797wpdoc8galluprifinaltextrigentoc061397 QST Environmental




Submitted to

US EPA - Region I


Prepared by

QST Environmental



June 1997



Executive Summary























October 11 1995









(603) 889-3737





QUADRANGLE LOCATION












sampling events








































































from the Site




































included



















following




































contamination







Disposal Area and











addressed in the FS











wetland

E412 Geology

























the south



E413 Hydrogeology








0001 cms









Horizontal Flow
























Figure E-2





Vertical Flow





gradient








N

LEGEND

WATERCOURSE

PROPERTY BOUNDARY



NOTES




400 400 800

SCALE IN FEET


(603) 889-3737 UmHOHHM



FIGURE E-2






E414 Ecology















RI program




late 1970s










the Site





Former Seepage Bed










than two years



















plume











Table of Contents

Section Page






21 Site Survey 2-1




























282 Slug Tests 2-26
















314 Climate 3-3

32 Geology 3-3





33 Hydrogeology 3-9



34 Ecology 3-17



















432 Sediment 4-31


44 Air Quality 4-34





51 Theory 5-1















611 Geology 6-1



70 References 7-1




List of Tables
















































































1996












of Site







List of Figures






Disposal Areas


























Figure 5-1

Figure 5-2

Figure 5-3





Plume





List of Plates





















1994






Events







List of Appendices






















Generation



10 Introduction






























1995







well samples















































411















































































































































investigators)










shown in Figure 1-4






Brook

























cadmium and lead















Table 1-1


are as follows

bull October 1979

bull January 1980

bull November 1980

bull April 1981

bull October 1981

bull April 1982





































area




















































1983)
















of 87 to 345 ppm






not detected


















sampling in 1982























































Pervel Industries





















flock plant







































































(USEPA 1987)

























































































bull lunch area



















of the Site






































along each line






















































































































bull benzene

bull toluene

bull acetone





following metals

bull aluminum

bull arsenic

bull cadmium

bull chromium

bull copper



bull iron

bull lead

bull manganese

bull nickel

bull zinc





less than 2


















































































installation






for analysis









bull benzene

bull toluene

bull acetone









































Appendix C











































analysis
























MW114 andMW116) and


















horizon











following



















TALTCL parameters





overburden







in Section 273





Section 273

























































(EPA Method 9060)























































































riser






























































282 Slug Tests











report













in Appendix F






















IBNovember 1995

















































































Table 2-5






























measurements


































Monitoring Program



















21311 Vegetation







21312 Hydrology





21313 Hydric Soils




























stained soil)

































operations







level








































































































deposits is minor












































































the line




































































discrete faults



















































the south


















Southern Study Area




















Northern Study Area































































3323 Vertical Flow

















Overburden
































































































entire stream flow












conditions





























































































UBS LB2)



























billion (ppb)





























































asphalt pavement



























































4131 EM-31 Survey































































location








































































surface soil sample










SB101 at 87 ppm





















































to 97 ppm



































effort



























































































categories























































































location



















































4221 VOC






42211 Overburden

Northern Study Area































MW105S















































to 430 ppb







































Southern Study Area








42212 Bedrock




















































































4224 Inorganics































to be valid










































4234 Inorganics



































































































Total Metals









(Hem 1989)

Dissolved Metals
























432 Sediment


















Boerngen 1984)

4322 VOC - Sediment












LB-1 and LB-2






nearby roads












production

433 Wetland Soils




QW1 (160000) QW2 (54600) QW3 (37200) QW4 (35200) QW5 (23900) QW6 (25600)




























detection limit







area

































































T



Water Supplies















supply










Day Care Facilities












are discussed







where






points









5111 Sorption






1979)






C = AT C

where
















Kx = 063












from 1 to 10 mgL

512 Dispersion

























where





DL =

where





where









Gelhar et al (1985)











Area
















11-dichloroethene




parent compound




X = ln(2)tm





mechanisms














515 Volatilization




H = C 1C




unsaturated soil










































SB 104 15-17 lt1500

SB104 26-28 1700

SB108 6-8 lt1500

SB 109 4-8 1600

SB109 10-16 lt1500

SB109 17-24 1500

SB109 24-32 1600
































































p v = J V h )





P =-raquo v Ltotal




















disposal areas































































































































































































or 1992 (TCA)










MW101



















n - b







5233 Summary

























611 Geology


















feet








^

612 Hydrogeology










almost 70 feet








cir









Groundwater Flow










Area





























































































important component


































Study Area



70 References







pp July 1990










Connecticut



481 scale 124000













June 19 1996


September 24 1996


December 18 1996


March 31 1997


May 21 1997




New Jersey












1979





Washington DC





















v26 no 10 pp2317-2329








pp 81-108




87001 (NTIS No PB88-181557)








124000

0 A 2

SCALE IN MILES

OONNECnCPT

OlMDIMNGLE LOCATION



(603) 689-3737



FIGURE 1-1



N

500 0 500

SCALE IN FEET

LOT NUMBER OWNER



LEGEND

D LOT NUMBER


PROPERTY BOUNDARY

NOTES





(603) 889-3737



FIGURE 1-2 1000



GB

N

LEGEND

WATERCOURSE



PROPERTY

CLASS Be

BOUNDARY

SURFACE WATER




NOTES


DRAWING NO 707600




TOWN OF




(603) 889-3737



500 0

SCALE IN

500

FEET

1000 FIGURE 1-3




G1097

LEGEND

WATERCOURSE

PROPERTY BOUNDARY


NOTES





(603) 869-3737



500 0 500 1000 FIGURE 1-4







Street 03063

(603) 889-3737







1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-101S MW-101TT MW-1 01 T


1450shy

OJ 2

LLJ 1445shy

O CO


1435

LLJ _l HI DC LJJ

I QZ

O cc CD

1430shy

1425shy

1420 010195

1 041195

1 072095

1 102895 020596

I 051596

I 082396

1 120196

1 031197 061997

DATE



1450

CO

LLJ 1445shy


lt 1435shy

LLJ _J LLJ

CC LLJ 1430shy

I Q Z D O CC C5

1425

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-104S MW-104TT


1450

CO2 LLJ 1445shy

O CO

1440shy

1435shy

LLI

LU tr QJ 1430shy

I Q

D O cc O

1425shy

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-105S MW-105TT MW-105T -X- MW-105B

1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-106S MW-106TT

1450


1415 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-103S MW-103TT


1490

CO

x- -X

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997



1465shy

(02 LU

1460shy

O CO

1455shy

1450shy

LU

LU

CC LU

lt

1445shy

1440shy

Q

mdashJocc O

14j vshy^

1430 010195

1 041195

1

072095 1

102895 T T

020596 051596

DATE 082396

1 120196 031197 061997

MW-1083 MW-1 08TT MW-1 08B

1580


(0 1575shy

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-109S MW-109B

1470


1450 i 1 i i i 1 r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-110S

1610


1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-111B

1590


lt) 1580shy

149 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-1123 MW-112T MW-112B


1510shy

2UJ

O m lt

1500shy

1490shy

1480shy

LU _l LJJ

CC LU

1470shy

1460shy

Q

OCC O

145degH

1440 010195 041195 072095

1 102895 020596 051596

DATE 082396

1 120196

1 031197 061997

MW-113S MW-113B

1580


1460 i r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-114S MW-114TT

150


1465 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE


1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-116S MW-116T


1480shy

CO

LJJ gto CD

1475shy

1470shy

LU LU

CC LU

1465shy


O z D O CC (5

1460shy

1455 010195

1 041195 072095

I 102895

1 1020596 051596

DATE

1 082396 120196 031197 061997

MW-117S MW-117TT


1465shy

LU 1440shy

LLJ


I Q Z D O CC CD

1430shy

1425shy


1420 010195

1 041195

I 072095

1 102895 020596

1 051596

DATE 082396 120196 031197 061997

MW-118S MW-118TT


1475shy

CO2 LJJ

1470shy

o m

1465shy

1460shy

UJ_i UJ cc LJJ

1455

1450shy


Q Z

O cc O

1445shy

1440 010195 041195

1 072095

I102895

I I 020596 051596

DATE

1 082396

i 1 201 96 031 1 97 061 997

MW-119S MW-119TT

1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

SW-3S SW-3D

Originals in color

VERTICAL


DISPOSAL AREA

MILL BROOK

NOTES (1)

(2)(3)






FIGURE 3-21






P 1 V |

1deg4 i

4 mI U 5 k 4 3

i i f J |103 1I Un |

|io2 bull m2




1I Un =

m4

104 I U sect

J 1I 3 bull PCE -m


2 ^ TCE 102

m



bull A1


=


i- r- -3 4 1 1995

MW105TT MW107TT 105 105

E pound

i shy104








^

-5lt 5amp -s= z1

1995 1995


CO

NC

ENTR

ATIO

N (

ppb)

IU sect MW102S

s 105 MW102TT

104 1 i 104

103 1 103

102 I I A sect 102

1

A

T

1 101

10deg i 10deg


1995 1995

bull PCE

bull TCA A TCE

bull 12-DCE

T VINYL CHLORIDE

MW101TT 105

104

103

102

10deg

BDL

1995


(603) 889-3737



FIGURE 5-2



s

104 tmdash a IU I

1 IU103 U-o 1F= E


BDL Emdash oS

105 i

104 i

103 i

102 bull

101 1

10deg

BDL 0S

105 9

104 B

103 I

102 i

101

10deg 1

BDL OCOogt

^ 00 ogt

^ra lt cltJgt

C O 0 0

0gt

MW-A

4 bull

1 1 1

co 01

MW-B

_J 1 1

1

i CO

8)

MW-C

11 1

lt lt

CO CO ogt

bullbull

laquoftr i i bull i

mn

Tbull1

bullbull

bull i

9

bull


egt lt t a) a

aai Tshy^

WM cN gjcI) lt J1

bull 1

bull 11 1

MM bullMl bullfr- 1

c4 0aigt C


T ^


10 |

-iM 10 s

-irvS 10 |

nn2 10

bullm1 bull

1UJ

oni AZs

^^^f

MW116T

A a

A =J =3

1995

bull

bullA

PCE

TCA

TCE

1 2-DCE

sect

1

s

I I 1

A gti

T VINYL CHLORIDE



nmranmini x



FIGURE 5-3





bull PCE (603) 889-3737




FIGURE 5-4






Submitted to

US EPA - Region I


Prepared by

QST Environmental



June 1997



Executive Summary























October 11 1995









(603) 889-3737





QUADRANGLE LOCATION












sampling events








































































from the Site




































included



















following




































contamination







Disposal Area and











addressed in the FS











wetland

E412 Geology

























the south



E413 Hydrogeology








0001 cms









Horizontal Flow
























Figure E-2





Vertical Flow





gradient








N

LEGEND

WATERCOURSE

PROPERTY BOUNDARY



NOTES




400 400 800

SCALE IN FEET


(603) 889-3737 UmHOHHM



FIGURE E-2






E414 Ecology















RI program




late 1970s










the Site





Former Seepage Bed










than two years



















plume











Table of Contents

Section Page






21 Site Survey 2-1




























282 Slug Tests 2-26
















314 Climate 3-3

32 Geology 3-3





33 Hydrogeology 3-9



34 Ecology 3-17



















432 Sediment 4-31


44 Air Quality 4-34





51 Theory 5-1















611 Geology 6-1



70 References 7-1




List of Tables
















































































1996












of Site







List of Figures






Disposal Areas


























Figure 5-1

Figure 5-2

Figure 5-3





Plume





List of Plates





















1994






Events







List of Appendices






















Generation



10 Introduction






























1995







well samples















































411















































































































































investigators)










shown in Figure 1-4






Brook

























cadmium and lead















Table 1-1


are as follows

bull October 1979

bull January 1980

bull November 1980

bull April 1981

bull October 1981

bull April 1982





































area




















































1983)
















of 87 to 345 ppm






not detected


















sampling in 1982























































Pervel Industries





















flock plant







































































(USEPA 1987)

























































































bull lunch area



















of the Site






































along each line






















































































































bull benzene

bull toluene

bull acetone





following metals

bull aluminum

bull arsenic

bull cadmium

bull chromium

bull copper



bull iron

bull lead

bull manganese

bull nickel

bull zinc





less than 2


















































































installation






for analysis









bull benzene

bull toluene

bull acetone









































Appendix C











































analysis
























MW114 andMW116) and


















horizon











following



















TALTCL parameters





overburden







in Section 273





Section 273

























































(EPA Method 9060)























































































riser






























































282 Slug Tests











report













in Appendix F






















IBNovember 1995

















































































Table 2-5






























measurements


































Monitoring Program



















21311 Vegetation







21312 Hydrology





21313 Hydric Soils




























stained soil)

































operations







level








































































































deposits is minor












































































the line




































































discrete faults



















































the south


















Southern Study Area




















Northern Study Area































































3323 Vertical Flow

















Overburden
































































































entire stream flow












conditions





























































































UBS LB2)



























billion (ppb)





























































asphalt pavement



























































4131 EM-31 Survey































































location








































































surface soil sample










SB101 at 87 ppm





















































to 97 ppm



































effort



























































































categories























































































location



















































4221 VOC






42211 Overburden

Northern Study Area































MW105S















































to 430 ppb







































Southern Study Area








42212 Bedrock




















































































4224 Inorganics































to be valid










































4234 Inorganics



































































































Total Metals









(Hem 1989)

Dissolved Metals
























432 Sediment


















Boerngen 1984)

4322 VOC - Sediment












LB-1 and LB-2






nearby roads












production

433 Wetland Soils




QW1 (160000) QW2 (54600) QW3 (37200) QW4 (35200) QW5 (23900) QW6 (25600)




























detection limit







area

































































T



Water Supplies















supply










Day Care Facilities












are discussed







where






points









5111 Sorption






1979)






C = AT C

where
















Kx = 063












from 1 to 10 mgL

512 Dispersion

























where





DL =

where





where









Gelhar et al (1985)











Area
















11-dichloroethene




parent compound




X = ln(2)tm





mechanisms














515 Volatilization




H = C 1C




unsaturated soil










































SB 104 15-17 lt1500

SB104 26-28 1700

SB108 6-8 lt1500

SB 109 4-8 1600

SB109 10-16 lt1500

SB109 17-24 1500

SB109 24-32 1600
































































p v = J V h )





P =-raquo v Ltotal




















disposal areas































































































































































































or 1992 (TCA)










MW101



















n - b







5233 Summary

























611 Geology


















feet








^

612 Hydrogeology










almost 70 feet








cir









Groundwater Flow










Area





























































































important component


































Study Area



70 References







pp July 1990










Connecticut



481 scale 124000













June 19 1996


September 24 1996


December 18 1996


March 31 1997


May 21 1997




New Jersey












1979





Washington DC





















v26 no 10 pp2317-2329








pp 81-108




87001 (NTIS No PB88-181557)








124000

0 A 2

SCALE IN MILES

OONNECnCPT

OlMDIMNGLE LOCATION



(603) 689-3737



FIGURE 1-1



N

500 0 500

SCALE IN FEET

LOT NUMBER OWNER



LEGEND

D LOT NUMBER


PROPERTY BOUNDARY

NOTES





(603) 889-3737



FIGURE 1-2 1000



GB

N

LEGEND

WATERCOURSE



PROPERTY

CLASS Be

BOUNDARY

SURFACE WATER




NOTES


DRAWING NO 707600




TOWN OF




(603) 889-3737



500 0

SCALE IN

500

FEET

1000 FIGURE 1-3




G1097

LEGEND

WATERCOURSE

PROPERTY BOUNDARY


NOTES





(603) 869-3737



500 0 500 1000 FIGURE 1-4







Street 03063

(603) 889-3737







1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-101S MW-101TT MW-1 01 T


1450shy

OJ 2

LLJ 1445shy

O CO


1435

LLJ _l HI DC LJJ

I QZ

O cc CD

1430shy

1425shy

1420 010195

1 041195

1 072095

1 102895 020596

I 051596

I 082396

1 120196

1 031197 061997

DATE



1450

CO

LLJ 1445shy


lt 1435shy

LLJ _J LLJ

CC LLJ 1430shy

I Q Z D O CC C5

1425

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-104S MW-104TT


1450

CO2 LLJ 1445shy

O CO

1440shy

1435shy

LLI

LU tr QJ 1430shy

I Q

D O cc O

1425shy

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-105S MW-105TT MW-105T -X- MW-105B

1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-106S MW-106TT

1450


1415 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-103S MW-103TT


1490

CO

x- -X

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997



1465shy

(02 LU

1460shy

O CO

1455shy

1450shy

LU

LU

CC LU

lt

1445shy

1440shy

Q

mdashJocc O

14j vshy^

1430 010195

1 041195

1

072095 1

102895 T T

020596 051596

DATE 082396

1 120196 031197 061997

MW-1083 MW-1 08TT MW-1 08B

1580


(0 1575shy

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-109S MW-109B

1470


1450 i 1 i i i 1 r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-110S

1610


1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-111B

1590


lt) 1580shy

149 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-1123 MW-112T MW-112B


1510shy

2UJ

O m lt

1500shy

1490shy

1480shy

LU _l LJJ

CC LU

1470shy

1460shy

Q

OCC O

145degH

1440 010195 041195 072095

1 102895 020596 051596

DATE 082396

1 120196

1 031197 061997

MW-113S MW-113B

1580


1460 i r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-114S MW-114TT

150


1465 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE


1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-116S MW-116T


1480shy

CO

LJJ gto CD

1475shy

1470shy

LU LU

CC LU

1465shy


O z D O CC (5

1460shy

1455 010195

1 041195 072095

I 102895

1 1020596 051596

DATE

1 082396 120196 031197 061997

MW-117S MW-117TT


1465shy

LU 1440shy

LLJ


I Q Z D O CC CD

1430shy

1425shy


1420 010195

1 041195

I 072095

1 102895 020596

1 051596

DATE 082396 120196 031197 061997

MW-118S MW-118TT


1475shy

CO2 LJJ

1470shy

o m

1465shy

1460shy

UJ_i UJ cc LJJ

1455

1450shy


Q Z

O cc O

1445shy

1440 010195 041195

1 072095

I102895

I I 020596 051596

DATE

1 082396

i 1 201 96 031 1 97 061 997

MW-119S MW-119TT

1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

SW-3S SW-3D

Originals in color

VERTICAL


DISPOSAL AREA

MILL BROOK

NOTES (1)

(2)(3)






FIGURE 3-21






P 1 V |

1deg4 i

4 mI U 5 k 4 3

i i f J |103 1I Un |

|io2 bull m2




1I Un =

m4

104 I U sect

J 1I 3 bull PCE -m


2 ^ TCE 102

m



bull A1


=


i- r- -3 4 1 1995

MW105TT MW107TT 105 105

E pound

i shy104








^

-5lt 5amp -s= z1

1995 1995


CO

NC

ENTR

ATIO

N (

ppb)

IU sect MW102S

s 105 MW102TT

104 1 i 104

103 1 103

102 I I A sect 102

1

A

T

1 101

10deg i 10deg


1995 1995

bull PCE

bull TCA A TCE

bull 12-DCE

T VINYL CHLORIDE

MW101TT 105

104

103

102

10deg

BDL

1995


(603) 889-3737



FIGURE 5-2



s

104 tmdash a IU I

1 IU103 U-o 1F= E


BDL Emdash oS

105 i

104 i

103 i

102 bull

101 1

10deg

BDL 0S

105 9

104 B

103 I

102 i

101

10deg 1

BDL OCOogt

^ 00 ogt

^ra lt cltJgt

C O 0 0

0gt

MW-A

4 bull

1 1 1

co 01

MW-B

_J 1 1

1

i CO

8)

MW-C

11 1

lt lt

CO CO ogt

bullbull

laquoftr i i bull i

mn

Tbull1

bullbull

bull i

9

bull


egt lt t a) a

aai Tshy^

WM cN gjcI) lt J1

bull 1

bull 11 1

MM bullMl bullfr- 1

c4 0aigt C


T ^


10 |

-iM 10 s

-irvS 10 |

nn2 10

bullm1 bull

1UJ

oni AZs

^^^f

MW116T

A a

A =J =3

1995

bull

bullA

PCE

TCA

TCE

1 2-DCE

sect

1

s

I I 1

A gti

T VINYL CHLORIDE



nmranmini x



FIGURE 5-3





bull PCE (603) 889-3737




FIGURE 5-4




Executive Summary























October 11 1995









(603) 889-3737





QUADRANGLE LOCATION












sampling events








































































from the Site




































included



















following




































contamination







Disposal Area and











addressed in the FS











wetland

E412 Geology

























the south



E413 Hydrogeology








0001 cms









Horizontal Flow
























Figure E-2





Vertical Flow





gradient








N

LEGEND

WATERCOURSE

PROPERTY BOUNDARY



NOTES




400 400 800

SCALE IN FEET


(603) 889-3737 UmHOHHM



FIGURE E-2






E414 Ecology















RI program




late 1970s










the Site





Former Seepage Bed










than two years



















plume











Table of Contents

Section Page






21 Site Survey 2-1




























282 Slug Tests 2-26
















314 Climate 3-3

32 Geology 3-3





33 Hydrogeology 3-9



34 Ecology 3-17



















432 Sediment 4-31


44 Air Quality 4-34





51 Theory 5-1















611 Geology 6-1



70 References 7-1




List of Tables
















































































1996












of Site







List of Figures






Disposal Areas


























Figure 5-1

Figure 5-2

Figure 5-3





Plume





List of Plates





















1994






Events







List of Appendices






















Generation



10 Introduction






























1995







well samples















































411















































































































































investigators)










shown in Figure 1-4






Brook

























cadmium and lead















Table 1-1


are as follows

bull October 1979

bull January 1980

bull November 1980

bull April 1981

bull October 1981

bull April 1982





































area




















































1983)
















of 87 to 345 ppm






not detected


















sampling in 1982























































Pervel Industries





















flock plant







































































(USEPA 1987)

























































































bull lunch area



















of the Site






































along each line






















































































































bull benzene

bull toluene

bull acetone





following metals

bull aluminum

bull arsenic

bull cadmium

bull chromium

bull copper



bull iron

bull lead

bull manganese

bull nickel

bull zinc





less than 2


















































































installation






for analysis









bull benzene

bull toluene

bull acetone









































Appendix C











































analysis
























MW114 andMW116) and


















horizon











following



















TALTCL parameters





overburden







in Section 273





Section 273

























































(EPA Method 9060)























































































riser






























































282 Slug Tests











report













in Appendix F






















IBNovember 1995

















































































Table 2-5






























measurements


































Monitoring Program



















21311 Vegetation







21312 Hydrology





21313 Hydric Soils




























stained soil)

































operations







level








































































































deposits is minor












































































the line




































































discrete faults



















































the south


















Southern Study Area




















Northern Study Area































































3323 Vertical Flow

















Overburden
































































































entire stream flow












conditions





























































































UBS LB2)



























billion (ppb)





























































asphalt pavement



























































4131 EM-31 Survey































































location








































































surface soil sample










SB101 at 87 ppm





















































to 97 ppm



































effort



























































































categories























































































location



















































4221 VOC






42211 Overburden

Northern Study Area































MW105S















































to 430 ppb







































Southern Study Area








42212 Bedrock




















































































4224 Inorganics































to be valid










































4234 Inorganics



































































































Total Metals









(Hem 1989)

Dissolved Metals
























432 Sediment


















Boerngen 1984)

4322 VOC - Sediment












LB-1 and LB-2






nearby roads












production

433 Wetland Soils




QW1 (160000) QW2 (54600) QW3 (37200) QW4 (35200) QW5 (23900) QW6 (25600)




























detection limit







area

































































T



Water Supplies















supply










Day Care Facilities












are discussed







where






points









5111 Sorption






1979)






C = AT C

where
















Kx = 063












from 1 to 10 mgL

512 Dispersion

























where





DL =

where





where









Gelhar et al (1985)











Area
















11-dichloroethene




parent compound




X = ln(2)tm





mechanisms














515 Volatilization




H = C 1C




unsaturated soil










































SB 104 15-17 lt1500

SB104 26-28 1700

SB108 6-8 lt1500

SB 109 4-8 1600

SB109 10-16 lt1500

SB109 17-24 1500

SB109 24-32 1600
































































p v = J V h )





P =-raquo v Ltotal




















disposal areas































































































































































































or 1992 (TCA)










MW101



















n - b







5233 Summary

























611 Geology


















feet








^

612 Hydrogeology










almost 70 feet








cir









Groundwater Flow










Area





























































































important component


































Study Area



70 References







pp July 1990










Connecticut



481 scale 124000













June 19 1996


September 24 1996


December 18 1996


March 31 1997


May 21 1997




New Jersey












1979





Washington DC





















v26 no 10 pp2317-2329








pp 81-108




87001 (NTIS No PB88-181557)








124000

0 A 2

SCALE IN MILES

OONNECnCPT

OlMDIMNGLE LOCATION



(603) 689-3737



FIGURE 1-1



N

500 0 500

SCALE IN FEET

LOT NUMBER OWNER



LEGEND

D LOT NUMBER


PROPERTY BOUNDARY

NOTES





(603) 889-3737



FIGURE 1-2 1000



GB

N

LEGEND

WATERCOURSE



PROPERTY

CLASS Be

BOUNDARY

SURFACE WATER




NOTES


DRAWING NO 707600




TOWN OF




(603) 889-3737



500 0

SCALE IN

500

FEET

1000 FIGURE 1-3




G1097

LEGEND

WATERCOURSE

PROPERTY BOUNDARY


NOTES





(603) 869-3737



500 0 500 1000 FIGURE 1-4







Street 03063

(603) 889-3737







1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-101S MW-101TT MW-1 01 T


1450shy

OJ 2

LLJ 1445shy

O CO


1435

LLJ _l HI DC LJJ

I QZ

O cc CD

1430shy

1425shy

1420 010195

1 041195

1 072095

1 102895 020596

I 051596

I 082396

1 120196

1 031197 061997

DATE



1450

CO

LLJ 1445shy


lt 1435shy

LLJ _J LLJ

CC LLJ 1430shy

I Q Z D O CC C5

1425

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-104S MW-104TT


1450

CO2 LLJ 1445shy

O CO

1440shy

1435shy

LLI

LU tr QJ 1430shy

I Q

D O cc O

1425shy

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-105S MW-105TT MW-105T -X- MW-105B

1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-106S MW-106TT

1450


1415 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-103S MW-103TT


1490

CO

x- -X

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997



1465shy

(02 LU

1460shy

O CO

1455shy

1450shy

LU

LU

CC LU

lt

1445shy

1440shy

Q

mdashJocc O

14j vshy^

1430 010195

1 041195

1

072095 1

102895 T T

020596 051596

DATE 082396

1 120196 031197 061997

MW-1083 MW-1 08TT MW-1 08B

1580


(0 1575shy

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-109S MW-109B

1470


1450 i 1 i i i 1 r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-110S

1610


1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-111B

1590


lt) 1580shy

149 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-1123 MW-112T MW-112B


1510shy

2UJ

O m lt

1500shy

1490shy

1480shy

LU _l LJJ

CC LU

1470shy

1460shy

Q

OCC O

145degH

1440 010195 041195 072095

1 102895 020596 051596

DATE 082396

1 120196

1 031197 061997

MW-113S MW-113B

1580


1460 i r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-114S MW-114TT

150


1465 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE


1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-116S MW-116T


1480shy

CO

LJJ gto CD

1475shy

1470shy

LU LU

CC LU

1465shy


O z D O CC (5

1460shy

1455 010195

1 041195 072095

I 102895

1 1020596 051596

DATE

1 082396 120196 031197 061997

MW-117S MW-117TT


1465shy

LU 1440shy

LLJ


I Q Z D O CC CD

1430shy

1425shy


1420 010195

1 041195

I 072095

1 102895 020596

1 051596

DATE 082396 120196 031197 061997

MW-118S MW-118TT


1475shy

CO2 LJJ

1470shy

o m

1465shy

1460shy

UJ_i UJ cc LJJ

1455

1450shy


Q Z

O cc O

1445shy

1440 010195 041195

1 072095

I102895

I I 020596 051596

DATE

1 082396

i 1 201 96 031 1 97 061 997

MW-119S MW-119TT

1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

SW-3S SW-3D

Originals in color

VERTICAL


DISPOSAL AREA

MILL BROOK

NOTES (1)

(2)(3)






FIGURE 3-21






P 1 V |

1deg4 i

4 mI U 5 k 4 3

i i f J |103 1I Un |

|io2 bull m2




1I Un =

m4

104 I U sect

J 1I 3 bull PCE -m


2 ^ TCE 102

m



bull A1


=


i- r- -3 4 1 1995

MW105TT MW107TT 105 105

E pound

i shy104








^

-5lt 5amp -s= z1

1995 1995


CO

NC

ENTR

ATIO

N (

ppb)

IU sect MW102S

s 105 MW102TT

104 1 i 104

103 1 103

102 I I A sect 102

1

A

T

1 101

10deg i 10deg


1995 1995

bull PCE

bull TCA A TCE

bull 12-DCE

T VINYL CHLORIDE

MW101TT 105

104

103

102

10deg

BDL

1995


(603) 889-3737



FIGURE 5-2



s

104 tmdash a IU I

1 IU103 U-o 1F= E


BDL Emdash oS

105 i

104 i

103 i

102 bull

101 1

10deg

BDL 0S

105 9

104 B

103 I

102 i

101

10deg 1

BDL OCOogt

^ 00 ogt

^ra lt cltJgt

C O 0 0

0gt

MW-A

4 bull

1 1 1

co 01

MW-B

_J 1 1

1

i CO

8)

MW-C

11 1

lt lt

CO CO ogt

bullbull

laquoftr i i bull i

mn

Tbull1

bullbull

bull i

9

bull


egt lt t a) a

aai Tshy^

WM cN gjcI) lt J1

bull 1

bull 11 1

MM bullMl bullfr- 1

c4 0aigt C


T ^


10 |

-iM 10 s

-irvS 10 |

nn2 10

bullm1 bull

1UJ

oni AZs

^^^f

MW116T

A a

A =J =3

1995

bull

bullA

PCE

TCA

TCE

1 2-DCE

sect

1

s

I I 1

A gti

T VINYL CHLORIDE



nmranmini x



FIGURE 5-3





bull PCE (603) 889-3737




FIGURE 5-4





(603) 889-3737





QUADRANGLE LOCATION












sampling events








































































from the Site




































included



















following




































contamination







Disposal Area and











addressed in the FS











wetland

E412 Geology

























the south



E413 Hydrogeology








0001 cms









Horizontal Flow
























Figure E-2





Vertical Flow





gradient








N

LEGEND

WATERCOURSE

PROPERTY BOUNDARY



NOTES




400 400 800

SCALE IN FEET


(603) 889-3737 UmHOHHM



FIGURE E-2






E414 Ecology















RI program




late 1970s










the Site





Former Seepage Bed










than two years



















plume











Table of Contents

Section Page






21 Site Survey 2-1




























282 Slug Tests 2-26
















314 Climate 3-3

32 Geology 3-3





33 Hydrogeology 3-9



34 Ecology 3-17



















432 Sediment 4-31


44 Air Quality 4-34





51 Theory 5-1















611 Geology 6-1



70 References 7-1




List of Tables
















































































1996












of Site







List of Figures






Disposal Areas


























Figure 5-1

Figure 5-2

Figure 5-3





Plume





List of Plates





















1994






Events







List of Appendices






















Generation



10 Introduction






























1995







well samples















































411















































































































































investigators)










shown in Figure 1-4






Brook

























cadmium and lead















Table 1-1


are as follows

bull October 1979

bull January 1980

bull November 1980

bull April 1981

bull October 1981

bull April 1982





































area




















































1983)
















of 87 to 345 ppm






not detected


















sampling in 1982























































Pervel Industries





















flock plant







































































(USEPA 1987)

























































































bull lunch area



















of the Site






































along each line






















































































































bull benzene

bull toluene

bull acetone





following metals

bull aluminum

bull arsenic

bull cadmium

bull chromium

bull copper



bull iron

bull lead

bull manganese

bull nickel

bull zinc





less than 2


















































































installation






for analysis









bull benzene

bull toluene

bull acetone









































Appendix C











































analysis
























MW114 andMW116) and


















horizon











following



















TALTCL parameters





overburden







in Section 273





Section 273

























































(EPA Method 9060)























































































riser






























































282 Slug Tests











report













in Appendix F






















IBNovember 1995

















































































Table 2-5






























measurements


































Monitoring Program



















21311 Vegetation







21312 Hydrology





21313 Hydric Soils




























stained soil)

































operations







level








































































































deposits is minor












































































the line




































































discrete faults



















































the south


















Southern Study Area




















Northern Study Area































































3323 Vertical Flow

















Overburden
































































































entire stream flow












conditions





























































































UBS LB2)



























billion (ppb)





























































asphalt pavement



























































4131 EM-31 Survey































































location








































































surface soil sample










SB101 at 87 ppm





















































to 97 ppm



































effort



























































































categories























































































location



















































4221 VOC






42211 Overburden

Northern Study Area































MW105S















































to 430 ppb







































Southern Study Area








42212 Bedrock




















































































4224 Inorganics































to be valid










































4234 Inorganics



































































































Total Metals









(Hem 1989)

Dissolved Metals
























432 Sediment


















Boerngen 1984)

4322 VOC - Sediment












LB-1 and LB-2






nearby roads












production

433 Wetland Soils




QW1 (160000) QW2 (54600) QW3 (37200) QW4 (35200) QW5 (23900) QW6 (25600)




























detection limit







area

































































T



Water Supplies















supply










Day Care Facilities












are discussed







where






points









5111 Sorption






1979)






C = AT C

where
















Kx = 063












from 1 to 10 mgL

512 Dispersion

























where





DL =

where





where









Gelhar et al (1985)











Area
















11-dichloroethene




parent compound




X = ln(2)tm





mechanisms














515 Volatilization




H = C 1C




unsaturated soil










































SB 104 15-17 lt1500

SB104 26-28 1700

SB108 6-8 lt1500

SB 109 4-8 1600

SB109 10-16 lt1500

SB109 17-24 1500

SB109 24-32 1600
































































p v = J V h )





P =-raquo v Ltotal




















disposal areas































































































































































































or 1992 (TCA)










MW101



















n - b







5233 Summary

























611 Geology


















feet








^

612 Hydrogeology










almost 70 feet








cir









Groundwater Flow










Area





























































































important component


































Study Area



70 References







pp July 1990










Connecticut



481 scale 124000













June 19 1996


September 24 1996


December 18 1996


March 31 1997


May 21 1997




New Jersey












1979





Washington DC





















v26 no 10 pp2317-2329








pp 81-108




87001 (NTIS No PB88-181557)








124000

0 A 2

SCALE IN MILES

OONNECnCPT

OlMDIMNGLE LOCATION



(603) 689-3737



FIGURE 1-1



N

500 0 500

SCALE IN FEET

LOT NUMBER OWNER



LEGEND

D LOT NUMBER


PROPERTY BOUNDARY

NOTES





(603) 889-3737



FIGURE 1-2 1000



GB

N

LEGEND

WATERCOURSE



PROPERTY

CLASS Be

BOUNDARY

SURFACE WATER




NOTES


DRAWING NO 707600




TOWN OF




(603) 889-3737



500 0

SCALE IN

500

FEET

1000 FIGURE 1-3




G1097

LEGEND

WATERCOURSE

PROPERTY BOUNDARY


NOTES





(603) 869-3737



500 0 500 1000 FIGURE 1-4







Street 03063

(603) 889-3737







1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-101S MW-101TT MW-1 01 T


1450shy

OJ 2

LLJ 1445shy

O CO


1435

LLJ _l HI DC LJJ

I QZ

O cc CD

1430shy

1425shy

1420 010195

1 041195

1 072095

1 102895 020596

I 051596

I 082396

1 120196

1 031197 061997

DATE



1450

CO

LLJ 1445shy


lt 1435shy

LLJ _J LLJ

CC LLJ 1430shy

I Q Z D O CC C5

1425

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-104S MW-104TT


1450

CO2 LLJ 1445shy

O CO

1440shy

1435shy

LLI

LU tr QJ 1430shy

I Q

D O cc O

1425shy

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997

MW-105S MW-105TT MW-105T -X- MW-105B

1450


1420 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-106S MW-106TT

1450


1415 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-103S MW-103TT


1490

CO

x- -X

1420 010195 041195 072095 102895 020596 051596

DATE 082396 120196 031197 061997



1465shy

(02 LU

1460shy

O CO

1455shy

1450shy

LU

LU

CC LU

lt

1445shy

1440shy

Q

mdashJocc O

14j vshy^

1430 010195

1 041195

1

072095 1

102895 T T

020596 051596

DATE 082396

1 120196 031197 061997

MW-1083 MW-1 08TT MW-1 08B

1580


(0 1575shy

1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-109S MW-109B

1470


1450 i 1 i i i 1 r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-110S

1610


1530 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-111B

1590


lt) 1580shy

149 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-1123 MW-112T MW-112B


1510shy

2UJ

O m lt

1500shy

1490shy

1480shy

LU _l LJJ

CC LU

1470shy

1460shy

Q

OCC O

145degH

1440 010195 041195 072095

1 102895 020596 051596

DATE 082396

1 120196

1 031197 061997

MW-113S MW-113B

1580


1460 i r 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-114S MW-114TT

150


1465 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE


1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

MW-116S MW-116T


1480shy

CO

LJJ gto CD

1475shy

1470shy

LU LU

CC LU

1465shy


O z D O CC (5

1460shy

1455 010195

1 041195 072095

I 102895

1 1020596 051596

DATE

1 082396 120196 031197 061997

MW-117S MW-117TT


1465shy

LU 1440shy

LLJ


I Q Z D O CC CD

1430shy

1425shy


1420 010195

1 041195

I 072095

1 102895 020596

1 051596

DATE 082396 120196 031197 061997

MW-118S MW-118TT


1475shy

CO2 LJJ

1470shy

o m

1465shy

1460shy

UJ_i UJ cc LJJ

1455

1450shy


Q Z

O cc O

1445shy

1440 010195 041195

1 072095

I102895

I I 020596 051596

DATE

1 082396

i 1 201 96 031 1 97 061 997

MW-119S MW-119TT

1455


1425 010195 041195 072095 102895 020596 051596 082396 120196 031197 061997

DATE

SW-3S SW-3D

Originals in color

VERTICAL


DISPOSAL AREA

MILL BROOK

NOTES (1)

(2)(3)






FIGURE 3-21






P 1 V |

1deg4 i

4 mI U 5 k 4 3

i i f J |103 1I Un |

|io2 bull m2




1I Un =

m4

104 I U sect

J 1I 3 bull PCE -m


2 ^ TCE 102

m



bull A1


=


i- r- -3 4 1 1995

MW105TT MW107TT 105 105

E pound

i shy104








^

-5lt 5amp -s= z1

1995 1995


CO

NC

ENTR

ATIO

N (

ppb)

IU sect MW102S

s 105 MW102TT

104 1 i 104

103 1 103

102 I I A sect 102

1

A

T

1 101

10deg i 10deg


1995 1995

bull PCE

bull TCA A TCE

bull 12-DCE

T VINYL CHLORIDE

MW101TT 105

104

103

102

10deg

BDL

1995


(603) 889-3737



FIGURE 5-2



s

104 tmdash a IU I

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FIGURE 5-4



Documents

Remedial Investigation Report Volume 1 - Text and Figures · Durin angd 1993 199 EP2, A conducte ad limited investigation throug thhe Superfund Technical Assessmen &t Response Team