EPA Region 5 Records etr.

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Five-Year Review Report

Third Five-Year Review Report for

LaSalle Electric Utilities Site LaSalle, LaSalle County, Illinois

September 2009

Prepared by:

Illinois Environmental Protection Agency Springfield, Illinois

For U.S. EPA, Region 5

Approved by:

~ (l I-<'~ Date

Table of Contents

Section Page

List of Acronyms iv Executive Summary 1

1 INTRODUCTION 1-1

2 SITE CHRONOLOGy 2-1

3 BACKGROUND 3-1 3.1 Physical Characteristics 3-1 3.2 Land and Resource Use 3-1 3.3 History of Contamination 3-1 3.4 Initial Response 3-1 3.5 Basis for Taking Action 3-2

4 REMEDIAL ACTIONS 4-1 4.1 Remedy Selection 4-1 4.2 Remedy Implementation 4-2

4.2.1 PCB Soil Remediation 4-2 4.2.2 Ground Water Remediation 4-3

4.2.2.1 Groundwater Treatment Unit and Groundwater Quality 4-3 4.2.2.2 Soil Vapor Extraction Units 4-5 4.2.2.3 Phytoremediation Systems 4-5 4.2.2.4 Institutional Controls 4-6

5 PROGRESS SINCE THE LAST FIVE-YEAR REViEW 5-1

6 FIVE-YEAR REVIEW PROCESS 6-1 6.1 Administrative Components 6-1 6.2 Community Involvement 6-1 6.3 Document and Data Review 6-1

6.3.1 Groundwater 6-2 6.3.2 Groundwater Treatment Unit 6-2

6.4 Site Inspection 6-3 6.5 Interviews 6-3

7 TECHNICAL ASSESSMENT 7-1

8 ISSUES 8-1

9 RECOMMENDATIONS AND FOLLOW-UP ACTION 9-1

10 PROTECTIVENESS STATEMENT 10-1

11 NEXT REViEW 11-1

11

Figures

5-1 5-2 5-3 5-4

Tables

Table I: Table 2:

Page

Configuration of I, 1,1-TCA Plume, Average of 2004-2005 Data 5-3 Configuration of I, 1,1-TCA Plume, Average of 2008-2009 Data 5-4 Configuration ofTCE Plume, Average of 2004-2005 Data 5-5 Configuration ofTCE Plume, Average of 2008-2009 Data 5-6

Page

Institutional Controls Summary Table .4-2 Recommendations/Follow-up Actions 9-1

111

ARARs CAA CERCLA CFR CWA E&E ESD FS GAC GTU HOPE HRS ICs Illinois EPA LEU MCLs NAPL NCP NESHAPs NPL O&M OSHA OUI OU2 PCB PCE POTW ppb ppm PRP RAOs RCRA RI ROD RPM RRA SDWA SVE I,I,I-TCA TCE total I,2-DCE TSCA U.S. EPA VC VOC

List of Acronyms

applicable or relevant and appropriate requirements Clean Air Act Comprehensive Environmental Response, Compensation, and Liability Act Code of Federal Regulations Clean Water Act Ecology and Environment, Inc. Explanation of Significant Difference Feasibility Study granular activated carbon groundwater treatment unit high-density polyethylene Hazard Ranking System Institutional Controls Illinois Environmental Protection Agency LaSalle Electric Utilities maximum contaminant levels non-aqueous-phase liquid National Contingency Plan National Emission Standards for Hazardous Air Pollutants National Priorities List operation and maintenance Occupational Safety and Health Administration Operable Unit I Operable Unit 2 polychlorinated biphenyl tetrachloroethene Publicly Owned Treatment Works part per billion parts per million Potentially Responsible Party remedial action objectives Resource Conservation and Recovery Act Remedial Investigation Record of Decision Remedial Project Manager Residual Risk Assessment Safe Drinking Water Act soil vapor extraction I, I, I-trichloroethane trichloroethene total I,2-dichloroethene Toxic Substances Control Act United States Environmental Protection Agency vinyl chloride volatile organic compound

IV

E:Kec:utive Summary

The remedy for the LaSalle Electric Utilities (LEU) site located in LaSalle, Illinois included the excava.tion and on-site incineration of contaminated soils. OU 1 consisted of excavation and on­site incineration of polychlorinated biphenyl (PCB) contaminated surface soil beyond the LEU propeJ1y along with industrial cleaning of structures where soil removal activities occurred. OU2 consi5,ted of the following components: 1) Excavation of PCB-contaminated soil on the LEU propeliy; 2) High-pressure flushing and mechanical cleaning of contaminated storm sewers; 3) Exca"ation of PCB-contaminated sediments from the unnamed creek downstream of the storm sewer discharge; 4) On-site incineration of PCB-contaminated soil and sediment; and 5) Construction of a groundwater collection and treatment system.

The initial Five-Year Review found that the remedy was constructed and operated in accordance with the requirements of the Record of Decision (ROD). At the end of the second Five-Year Review, one Explanation of Significant Difference (ESD) was issued to account for the addition of remedy enhancements (i.e., two soil vapor extraction systems and two phytoremediation pl'Jts), which were implemented to reduce the potential that volatile organic compound (VOC) groundwater concentrations will increase (i.e., rebound effect) once groundwater extraction and treatment is discontinued. The remedy functioned as designed, and the groundwater monitoring results showed a significant reduction in the concentrations of trichloroethene (TCE) and 1,1,1­trichloroethane (I, 1,1-TCA) in the groundwater.

During this third Five-Year Review, the groundwater extraction and groundwater treatment unit (GTU) and the two soil vapor extraction (SVE) systems were shut down due to an end in federal government funding, Illinois Environmental Protection Agency (Illinois EPA) budget issues, and to allow long-term observation and assessment of contaminant rebound effects in groundwater. Prior to the shutdown, a Residual Risk Assessment (RRA) was conducted to evaluate the potemial risks to human health and the environment that could result from the system shutdown. A re-examination of the municipal water supply system and a survey of private residential wells in the area determined that shallow groundwater is not currently used for potable purposes and a LaSalle City ordinance prohibiting the use of the shallow groundwater is in place. The risks associ ated with potential contaminated vapor intrusion into nearby residences and commercial buildings were assessed. The results of the draft RRA indicated that the maximum cancer risks arid noncancer hazards were well below levels of potential concern.

Currently, the two phytoremediation plots remain in operation, and groundwater at the site continues to be sampled semiannually to monitor changes in contaminant concentrations, as well as to monitor groundwater flow patterns. The remedy shutdowns have not resulted in a si gnificant increase in contaminant concentrations or in the areal extent of the 1,1,1-TCA and TeE :Jlumes. During the third Five-Year Review period, migration of the TCE plume along the more permeable backfill material surrounding the groundwater collection system laterals was observed to the south. However, migration beyond the laterals appears to be limited due to the native silty clay soils beyond the backfill. The groundwater flow direction has returned to pre­GTU operation conditions, and water levels have risen 12 to 15 feet since shutdown of the collec:tion system. There currently are no immediate threats. However, continued groundwater

monitoring will be conducted to assess any further changes in site conditions that may result in risks to human health and the environment.

The protectiveness for each OU and on a site-wide basis is as follows:

OUI - Remedy is protective.

OU2 - Remedy is protective in the short term because there is no evidence that there are current exposures. In order for the remedy to remain protective in the long term, the groundwater extraction, GTU, and SVE systems must be re-started and the LaSalle City ordinance prohibiting use of the shallow groundwater must be verified and monitored.

Site wide - The remedies implemented at the site for the entire site are protective in the short term because there is no current exposure. In order for the remedies to remain protective in the long term, the groundwater extraction, GTU, and SVE systems must be re-started Additionally, long term protectiveness requires compliance with effective institutional controls until the cleanup standards have been met. A LaSalle City ordinance exists to prohibit construction of any private wells for the purpose of obtaining a water supply. Compliance with effective institutional controls will be ensured by: verifying the existence of the ordinance; reviewing its effectiveness; and ensuring the ICs are monitored, maintained and enforced. Finally, the remedy will be modified to formally incorporate the ICs.

2

Five-Year Review Summary Form

SITE IDE.\TIFIC t TIO.\'

Site name (from WasteLAN): LaSalle Electrical Utilities

EPA 10 (from WasteLAN): ILD980794333

•

SITE ST-t Tl 'S

NF'L s,tatus: .,j Final 0 Deleted 0 Other (specify)

Remediation status (choose all that apply): 0 Under Construction 0 Operating .,j Complete

Multiple OUs?· .,j YES 0 NO Construction completion date: 02 /28 /1994

Has site been put into reuse? Off-Site au .,j YES 0 NO; On-Site au 0 YES .,j NO

REf JEW ST I TioS

Lead ,agency: 0 EPA .,j State 0 Tribe o Other Federal Agency

Author name: Richard Lange

AUithor title: Remedial Project Author affiliation: Illinois Environmental Manager Protection Agency

Re'view period:·· 09 /27 /2004 to 09 /27 /2009

Da!!t:s) of site inspection: 08/31 /2009

Type of review: .,j Post-SARA o Pre-SARA o NPL-Removal only

o Non-NPL Remedial Action Site o NPL StatefTribe-lead

o Regional Discretion

RE!vieW number: 0 1 (first) 02 (second) ,/ 3 (third) o Other (specify)

Triiggering action: o ActucII RA Onsite Construction at au #__ []Actual RA Start at OU#_

o Cons truction Completion .,j Previous Five-Year Review Report

OOtheI" (specify)

Tr~ering action date (from WasteLAN): 09/27/2004

Due clate (five years after triggering action date): 09/27/2009-• I"OU . refers to operable umt.]*. [Review period should correspond to the actual start and end dates of the Five-Year Review in WasteLAN 0]

3

Five-Year Review Summary Form, cont'd.

Issues: The following issues have been identified that may prevent the remedy from being protective:

1). The groundwater extraction, GTU, and SVE systems have been shut down for an observational period but have yet to be restarted;

2). Groundwater monitoring may need to be modified to fully understand the current conditions of the aquifer due to the extended shutdown period; and

3). Institutional controls are not included in the OU 2 ROD or the ESD for the site which would prevent exposure to contaminated groundwater until the aquifer is restored to beneficial reuse. However, there is a LaSalle City Ordinance prohibiting use of the shallow groundwater. This IC needs to be evaluated to ensure additional controls are not necessary.

Recommendations and Follow-up Actions:

Develop a plan to re-start the groundwater extraction, GTU, and SVE systems;

Update the groundwater monitoring requirements to fully evaluate the extended shutdown observational period; and

Develop a plan to formally adopt institutional controls as part of the remedy to prevent exposure to contaminated groundwater until it has been restored.

Protectiveness Statement(s):

OU 1 - Remedy is protective.

OU2 - Remedy is protective in the short term because there is no evidence that there are current exposures. In order for the remedy to remain protective in the long term, the groundwater extraction, GTU, and SVE systems must be re-started and the LaSalle City ordinance prohibiting use of the shallow groundwater must be verified and monitored.

Site wide - The remedies implemented at the site for the entire site are protective in the short term because there is no current exposure. In order for the remedies to remain protective in the long term, the groundwater extraction, GTU, and SVE systems must be re-started Additionally, long term protectiveness requires compliance with effective institutional controls until the cleanup standards have been met. A LaSalle City ordinance exists to prohibit construction of any private wells for the purpose of obtaining a water supply. Compliance with effective institutional controls will be ensured by: verifying the existence of the ordinance; reviewing its effectiveness; and ensuring the ICs are monitored, maintained and enforced. Finally, the remedy will be modified, to formally incorporate the ICs.

4

1 INTRODUCTION

The purpose of the Five-Year Review is to determine whether the remedy at a site is protective of human health and the environment. The methods, findings, and conclusions of reviews are documented in Five-Year Review reports. In addition, Five-Year Review reports identify issues found during the review, if any, and make recommendations to address them.

The lllinois Environmental Protection Agency (Illinois EPA) prepared this Five-Year Review pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) §121 and the National Contingency Plan (NCP). CERCLA §121 states:

Ifthe President selects a remedial action that results in any hazardous substances. pollutants, or contaminants remaining at the site, the President shall review such remedial action no less often than each jive years after the initiation ofsuch remedial action to assure that human health and the environment are being protected by the remedial action being implemented. In addition. ifupon such review it is the judgment ofthe President that action is appropriate at such site in accordance with section [J04} or [J-6}, the President shall take or require such action. The President shall report to the congress a list offacilities for which such review is required, the results ofall such reviews, and any actions taken as a result ofsuch reviews.

The Lnited States Environmental Protection Agency (U.S. EPA) interpreted this requirement further in the NCP; 40 Code of Federal Regulations (CFR) §300.430(f)(4)(ii), which states:

Ifa remedial action is selected that results in hazardous substances, pollutants, or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure, the lead agency shall review such action no less often than everyjive years after the initiation ofthe selected remedial action.

The lllinois EPA conducted the Five-Year Review of the remedy implemented at the LaSalle Electric Utilities (LEU) site located in LaSalle, Illinois. The review was performed under the di rection of the Illinois EPA's Remedial Project Manager (RPM) for the entire site from October 2004 Through September 2009. This report documents the results of the review.

This is the third Five-Year Review for the LEU site. The triggering action for this policy review was the completion of the second Five-Year Review in September 2004. A Five-Year Review is required because volatile organic compounds (YOCs), mainly trichloroethene (TCE), I, 1,1­tri chloroethane (1, 1,1-TCA), vinyl chloride (YC), and tetrachloroethene (PCE), were detected in site groundwater above their respective maximum contaminant levels (MCLs).

I-I

2 SITE CHRONOLOGY

Chronology of Site Events

Event

LEU cited for inadequate polychlorinated biphenyl (PCB) storage facilities by U.S. EPA.

Violation of PCB management practices documented by U.S. EPA and the Occupational Safety and Health Administration (OSHA).

U.S. EPA issues Toxic Substances Control Act (TSCA) complaint.

Illinois EPA soil sampling revealed extensive PCB contamination on the LEU property.

Illinois EPA soil sampling revealed PCB contamination on property beyond the LEU site.

Illinois EPA, under authority of Section 34 of the Illinois Environmental Protection Act, sealed all but the leased areas ofthe LEU property.

Illinois EPA conducted additional soil sampling in the area.

Illinois EPA filed a State of Illinois complaint.

Illinois EPA amended the State of Illinois complaint and also filed a Federal complaint under TSCA.

The U.S. EPA Field Investigation Team installed four monitoring wells at the site.

Based on the infonnation gathered, the site is included on the first publication of the National Priorities List (NPL). The Hazard Ranking System (HRS) score equaled 42.06.

A U.S. EPA contractor fenced part of the LEU property as an immediate removal measure at the site.

Date

September 1975

October 1979

July 1980

December 1980

March and May 1981

May 1981

June to September 1981

May 1982

August 1982

August 1982

December 1982

July 1983

2-1

E"ent

The U.S. EPA conducted additional sampling south of the LEU property. Results indicated heavy contamination on the property immediately to the south.

The u.s. EPA conducted an immediate removal action at thl~ site and capped the section of the property south of the LEU site, which was found to be heavily contaminated. This cap diverted drainage to an on-site pond that was also constructed.

Illinois EPA conducted additional soil and groundwater sampling in the area. Groundwater contamination, including VOCs and PCBs, was identified.

The u.s. EPA conducted an immediate removal action at thl~ site. PCB waste material that had been stored on the site was staged, sampled, and packaged for eventual disposal.

Draft Feasibility Study (FS) by an Illinois EPA contractor addressed contamination in area soils.

The Illinois EPA conducted an immediate removal at the site. An Illinois EPA contractor removed the previously staged material and transported it to a nearby incineration facility.

Draft Remedial Investigation (RI) report prepared by Illinois EPA.

Illinois EPA contractor prepares Phased Feasibility Study regarding soil contamination beyond the LEU property.

u.S. EPA Record of Decision regarding residential soil contamination is signed.

Illinois EPA contractor prepares design plans and specifications for the cleanup of contaminated residential soils.

Illinois EPA contractor conducts an investigation of groundwater contamination at the site.

Illinois EPA signs contract and begins preliminary work re lated to the cleanup of residential soils.

Date

July and October 1983

June 1984

June 1984 to July 1985

April 1985

August 1985

December 1985

January 1986

June to August 1986

August 1986

January to July 1986

January to December 1987

January 1988

2-2

Event

U.S. EPA Record of Decision regarding on-site soils and groundwater is signed.

Illinois EPA contractor begins off-site soil incineration.

Illinois EPA contractor completes off-site incineration.

Illinois EPA contractor begins on-site remedial efforts.

Illinois EPA contractor begins construction of the groundwater collection and treatment system.

Illinois EPA receives permit to discharge treated groundwater.

Groundwater extraction and treatment unit (GTU) started up.

Illinois EPA contractor completes on-site soil incineration.

Illinois EPA contractor conducts pilot testing of soil vapor extraction (SVE).

Initial Five-Year Review by Illinois EPA.

Illinois EPA contractor implements phytoremediation test plot in the northwest corner of the site.

Illinois EPA contractor begins construction of SVE systems.

Illinois EPA implements phytoremediation test plot along the eastern boundary of the site.

SVE systems begin operation.

Semiannual groundwater monitoring replaces quarterly groundwater monitoring.

U.S. EPA signs Explanation of Significant Difference (ESD) for remedy enhancements (SVE and phytoremediation).

Date

March 1988

November 1988

June 1989

August 1990

October 1991

April 1992

April 1993

October 1993

April 1999

September 1999

April 2002

September 2002

September 2002

March 2003

July 2003

July 2004

2-3

E"ent Date

St:cond Five-Year Review by Illinois EPA. September 2004

Illinois EPA contractor completes draft Residual Risk Assessment (RRA) to evaluate the risks associated with contaminated vapor intrusion into nearby residences and commercial buildings after remedy shutdown.

February 2005

GTU and SVE systems shut down due to end in federal government funding and to allow long-tenn observation and assessment of contaminant rebound effects in groundwater.

March 2005

Two phytoremediation plots are in operation and semiannual groundwater monitoring continues.

September 2009

2-4

3 BACKGROUND

3.1 Physical Characteristics

The LEU site is located in west-central LaSalle County, in the city of LaSalle in north-central Illinois (SE 1/4, SW 1/4 of Section 3, T33N, RIE). The LEU site address is 2427 St. Vincent Avenue. The site originally consisted of five buildings, which were interconnected to form one main complex. This complex included an office building, two metal buildings, a brick building, and a Quonset building. Additional small buildings (pump house, two hose houses, a thinner shed, a small incinerator building, and a sandblasting shed) and a stormwater holding pond that received stormwater runoff from the parking lot were also present on site.

Approximately 70 residences are located within 0.13 miles of the LEU property. Based on the 1980 Census data showing approximately 2.7 individuals per household in the area, it was estimated that these residences housed approximately 190 people. The land use to the north of the property is rural with an agricultural field separating the site from a residential development. Immediately south of the site are several commercial developments. East of the site is the residential area that was addressed by the PCB soil removal effort. Finally, a mixture of small businesses and residences lies to the west.

3.2 Land and Resource Use

LEU is a former manufacturer of electrical equipment. Operations at the site began prior to World War II, and in the late 1940s the plant began utilizing PCBs in the production of capacitors. This manufacturing practice continued until October 1978. During the 1970s, the company expanded its operations and opened another plant in Farmville, North Carolina. In May 1981, manufacturing operations ceased at the LaSalle site. Subsequently, the Illinois EPA, enforcing Section 34 of the Illinois Environmental Protection Act, ordered the production areas of the plant to be sealed. The LEU office building remained in use by a lessee until some time in the early 1980s, when it was abandoned.

3.3 History of Contamination

Information is limited on the waste management practices of the LEU Company. Undocumented reports allege that PCB-contaminated waste oils may have been applied as a dust suppressant both on the site and off the property as late as 1969. Following the regulation of PCBs, inventory reports for LEU document the disposal of PCBs at approved facilities.

3.4 Initial Response

Beginning in September 1975, numerous government agencies including the U.S. EPA, Illinois EPA, and OSHA conducted various inspections and issued myriad complaints and orders to the LEU Company as a result of its past manufacturing and handling practices.

3-1

Analysis of site records indicated there was only one Potentially Responsible Party (PRP), LEU, from which the U.S. EPA could seek reimbursement of costs associated with the investigation and removal of contamination from the site. However, LEU was not financially viable.

On September 19, 1983, LEU petitioned for relief under Chapter 11 of the Bankruptcy Act in the U.S. Bankruptcy Court, Wilson, North Carolina. On June 26, 1986, the court entered an order approving the company's planned liquidation.

From December 1980 through August 1982, multiple soil and groundwater sampling events were conducted at the LEU site. Based on the analytical results, the LEU site was included in the first publication of the NPL in December 1982. An HRS score of 42.06 was calculated for the LEU site.

Slarting in July 1983 and running through December 1987, additional site investigations and limited site removals were performed. Specifically, investigative reports prepared for the LEU site included a draft Feasibility Study addressing contamination in area soils (August 1985), a draft Remedial Investigation report (January 1986), and a Phased Feasibility Study addressing soil contamination beyond the LEU property (August 1986).

3.5 Basis for Taking Action

The exposure pathways of concern for OUI were direct contact or ingestion of contaminated soil. The exposure pathways of concern for OU2 were direct contact or ingestion of contaminated soil and groundwater. Hazardous substances identified in the March 1988 ROD for tht~ LEU site that have been released into each medium include:

Soil Groundwater Polychlorinated biphenyls Polychlorinated biphenyls* Volatlle organic compounds Trichloroethene*

Trans-l,2-dichloroethene 1,1,1-Trichloroethane*

S{:diment 1,I-Dichloroethane Polychlorinated biphenyls Vinyl chloride* Volatile organic compounds 1,I-Dichloroethene

Toluene Tetrachloroethene* Ethylbenzene Xylenes

* Primary constituent of concern.

3-2

4 REMEDIAL ACTIONS

4.1 Remedy Selection

The U.S. EPA elected to split the site into two separate operable units. The first operable unit (Phase I) dealt with PCB soil contamination beyond the LEU property (ROD dated August 1986) and required the following remedy components:

• The excavation of PCB-contaminated material above 5 parts per million (ppm) at the surface and above 10 ppm at depths greater than one foot and the replacement with clean fill. The materials would be thermally treated on the LEU property with a mobile incinerator which would be set up at that location. Provided that analysis of the residual material proves that it is uncontaminated, it could be used as cover material at a sanitary landfill or as fill in roadway and construction projects.

• Conventional industrial cleaning- includes vacuuming, hand washing, steam jet cleaning, and adsorption. This would address all structures (basements and garages included) where soil removal activities would have taken place. The entire building, including the heating/air conditioning ducts, would be vacuumed. Afterwards, floors and walls would be hand scrubbed and wiped with adsorbent cloths. Other hard surfaces, such as counter tops, table tops, ceilings, and vertical surfaces of cabinets would be wiped with a damp cloth. Wood floors would be waxed after they are cleaned, and any surfaces that are damaged by the cleaning processes would be refinished or replaced. Carpeting and upholstery would be stearn cleaned, while drapes and bedspreads would be dry cleaned under controlled conditions. The exterior walls and the gutters of the structures would be washed by hand. After all affected buildings are cleaned, samples will be collected from a representative number of locations to ensure that the cleaning process was successfully completed and met the selected clean-up level of 0.5 ug/l00cm2 for high contact surfaces and 10 ug/l00 cm2 for surfaces with infrequent contact.

The second operable unit (Phase II ROD dated March 30, 1988) addressed all remaining contamination and required the following:

• Excavation of PCB-contaminated soil on the LEU property; • High-pressure flushing and mechanical cleaning of contaminated sewer lines; • Excavation of PCB-contaminated sediment from the unnamed creek downstream of

the storm sewer discharge; • Incineration of PCB-contaminated soil and sediment by a mobile, on-site thermal

destruction unit; • Construction of a groundwater collection system on and/or near the LEU property;

and • Construction of an on-site treatment system that will process the VOC- and PCB­

contaminated groundwater collected.

4-1

The March 1988 OU2 ROD also stipulated that all applicable or relevant and appropriate requirements (ARARs) of other Federal and State environmental laws will be attained. Specifically, the ROD identified the following:

• Toxic Substances Control Act (TSCA). PCB disposal regulations under 40 CFR 761.60 require that PCB-contaminated soil at concentrations greater than 50 parts per million (ppm) be taken to a TSCA-regulated facility. Incineration of PCB waste must be able to meet a destruction removal efficiency of at least 99.999%. These requirements are applicable and will be met. In addition, residual material from the incinerator would be required to contain less than 2 ppm PCBs;

• Resource Conservation and Recovery Act (RCRA). Groundwater will be monitored for three years following attainment of cleanup levels consistent with corrective action minimum requirements under 40 CFR 264.100;

• Safe Drinking Water Act (SDWA). Contaminated groundwater will be collected to achieve Maximum Contaminant Levels for VOCs; PCBs will be removed to the 1­part per billion (ppb) level;

• Clean Water Act (CWA). Groundwater that is collected will be discharged to the local wastewater treatment plant following treatment and will meet pretreatment standards established pursuant to 40 CFR 403.5; and

• Clean Air Act (CAA). Emission control requirements may be applicable to emissions from the incinerator depending on their magnitude. Asbestos in the LEU buildings will be disposed of in accordance with National Emission Standards for Hazardous Air Pollutants (NESHAPs) for asbestos, 40 CFR 61.147.

Due to the identification of isolated contaminated portions of the groundwater plume which were not be,ing remediated as rapidly as expected and the large amount of clean groundwater being processed by the GTU, a series of remedy enhancements were implemented as discussed below. One enhancement was the installation of two phytoremediation plots to minimize the amount of clean water extracted by the system and to assist in the remediation of the isolated contaminant ar,~as. These plots required irrigation, which was provided by treated groundwater from the effluent of the GTU. An Explanation of Significant Differences (ESD) was signed on July 16, 2004 "to allow a portion of the treated groundwater previously being discharged to the local Publicly Owned Treatment Works (POTW) to be re-directed for use as irrigation water for the phytoremediation plots.

4.2 Remedy Implementation

4.2.1 PCB Soil Remediation

Phase I (OU1) was initiated in January 1988. Approximately 23,000 cubic yards of soil were removed from off-site properties and treated by the on-site incinerator. The remedial action also included industrial cleaning of structures on properties where significant excavation occurred.

4-2

Phase II (OU2) was initiated in July 1990, and approximately 68,000 cubic yards of on-site contaminated soil were incinerated. Additionally, high-pressure flushing and mechanical cleaning of contaminated sewer lines, and excavation of contaminated sediment from the unnamed creek downstream of the storm sewer discharge were performed.

Soil thermally treated by the on-site incinerator during Phase I of the project was used at a local land disposal facility as daily cover. The soil, sediments, and building demolition debris thermally treated during Phase II was used as on-site fill material. Upon completion of the thermal treatment, a soil cover was placed over the thermally treated soil, and a protective vegetative cover was established.

4.2.2 Ground Water Remediation

4.2.2.1 Groundwater Treatment Unit and Groundwater Quality

In April 1992, construction of the on-site groundwater collection and treatment system was initiated. The groundwater collection and treatment system became fully operational in April 1993. The groundwater collection system consists of a series of interconnected trenches that drain by gravity into a single collection manhole. From the manhole, the collected groundwater was pumped into the GTU.

The GTU included an acid feed system to adjust pH, an oil/water separator capable of removing both light and dense non-aqueous-phase oils, pressurized vessel filtration to remove particulate (including gypsum created by pH adjustment), twin air-stripping towers to remove VOCs from the influent with vapor-phase carbon adsorption of VOCs, and aqueous-phase granular activated carbon (GAC) to remove PCBs. Once treated, the groundwater was discharged to the local POTW.

In May 1999, after receipt of approval from the City of LaSalle, the GAC cells were taken off line. Previous sampling in 1998 indicated that the carbon cells were no longer needed to maintain the required effluent standards, and in an effort to maximize the throughput of the treatment system, the carbon cells were bypassed, allowing effluent from air stripper #2 to discharge directly to the city sewer connection. Because the carbon cells were taken off line, back-flushing the carbon cells was no longer required as part of routine operation and mainte­nance of the GTU. After the GTU shutdown, the spent carbon was extracted from the cells for proper disposal, and the carbon cells were removed from the site.

During the operation of the system, no oil was collected from the oil/water separator. The separator functioned as a settler for the suspended soil material that entered the collection system with the groundwater and for gypsum (CaS04) precipitates. This material was removed from the separator periodically via an under drain, and the unit was fully emptied when the system was shut down for routine maintenance. The sludge was pumped into used bag filters, placed on a drying rack, and allowed to dewater before being placed into 55-gallon drums with the bag filters. Water generated in this process was returned to the treatment system for re-treatment and discharge to the POTW and the drummed filters and dried sludge were sent for off-site disposal.

4-3

Throughout its operation, the performance of the GTU, as well as groundwater quality, has been monitored. Through 2002, groundwater samples were collected on a quarterly basis, and analyzed for VOCs and PCBs. In 2003, groundwater sampling and analysis were reduced to semi-annual events. Additionally, weekly influent and effluent samples from the GTU were collected and analyzed for VOCs and PCBs.

As part of the ongoing groundwater and GTU monitoring programs, Illinois EPA has contracted Ecology and Environment, Inc., (E & E) to gather and model data, and to develop reports of the findings. Reports generated by E & E to date include:

• Assessment ofPerformance Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit, Inception Through 1995, dated April 1996;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit 1996 Through 1997, dated April 1998;

• Summary Report, Phase I Investigation of VOCs in Subsurface Soils, dated July 1998;

• Focused Feasibility Study Report, Phase II Investigation ofVOCs in Subsurface Soils, dated January 1999;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit 1998, dated April 1999;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit 1999-2000, dated March 2001;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit, 2001, dated July 2003;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit 2002-2003, dated August 2004;

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit, January 2004-March 2006, dated June 2006; and

• Technical Memorandum, Groundwater Sampling Results, October 2006-March 2008, LaSalle Electric Utilities Site, dated July 2008.

Based on the data gathered during operations, the groundwater extraction system at the LEU site dt:veloped a sufficient hydraulic gradient to capture the contaminant plume. Analytical results al50 showed that no non-aqueous-phase liquid (NAPL) was present in the groundwater. Additionally, the GTU consistently met the POTW effluent limitations.

Whilt~ the contaminant plume had been captured, subsequent investigations conducted in early 1998 to refine the understanding of site hydrology determined that reduction in contaminant

4-4

concentrations was slower than the original predictions. Additionally, the data showed that the concentration ofVOCs at certain monitoring locations was steadily increasing. This trend suggested that there could be VOC-contaminated source areas remaining within the unsaturated zone, which led to additional investigations conducted in mid-1998. The additional soil investigations located three isolated on-site areas where the unsaturated zone had elevated VOC concentrations: the former Laboratory area, the Thinner Shed area, and the northwest comer of the site. In order to ensure that the groundwater MCLs were met in a timely fashion, remedy enhancements consisting of additional duel-phase soil vapor extraction units and two phytoremediation plots, were implemented to address these three isolated on-site source areas.

By the end of 2004, the total mass of contaminants in the extracted groundwater was minimal and approaching asymptotic levels. Additionally, the contract with the GTU operator was due to expire in March 2005, which also coincided with the completion ofthe long-term remedial action (LTRA) period. In March 2005, Illinois EPA decided it was an opportune time to shut down the groundwater extraction system and GTU to observe any rebound effects of the contaminant plume. This observational period would allow IEPA to thoroughly evaluate the progress of the remedy and to better estimate the time frame needed to complete the remedy. Consequently, IEPA decided to shut down the groundwater extraction system and the GTU in March 2005 once federal government funding was terminated to observe the responses of the contaminant plume. The entire groundwater collection system and most of the GTU components remain in place at the site.

4.2.2.2 Soil Vapor Extraction Units

Installation of dual-phase SVE units in the Laboratory area and in the Thinner Shed area was completed in January 2003, and the startup and shakedown period took place in February 2003. By pneumatically fracturing the site soils, an increase in the hydraulic conductivity of the remediation areas was achieved, thereby increasing soil vapor and groundwater extraction. By the end of2003, the Laboratory area SVE system had removed a total of20,930 gallons of groundwater, and 42,270 gallons had been removed by the Thinner Shed SVE system. The results of soil gas sampling for VOCs in 2004 indicated that biodegradation was occurring, and that an estimated 1.5 to 2 pounds ofVOCs per month were being removed by the SVE system. Prior to the shutdown of the SVE system in March 2005, semi-annual groundwater sample collection at selected extraction wells was initiated in the Laboratory area and the Thinner Shed area to assess any changes in source area concentrations as a result ofthe GTU shutdown.

4.2.2.3 Phytoremediation Systems

Two phytoremediation systems were installed in 2002. Located in the northwest comer of the site, the first system addresses PCE-contaminated soil and groundwater. The second system is located along the eastern side of the GTU parallel to St. Vincents Avenue. This phytoremediation system was installed to enhance collection of the TCE groundwater plume, and secondarily, as a hydraulic curtain to prevent migration ofVOCs off site after shutdown of the GTU.

4-5

In the northwest comer, an area approximately 95 feet by 235 feet was planted with fast-growing poplar, willow, and bald cypress trees in April 2002. Due to an unseasonably hard freeze on May 20, 2002, some poplar and all of the willow clones suffered significant stunting and/or mortality. The affected poplars and willows were removed, and these species were replanted in early 2003. A non-dedicated mobile spray gun irrigation system was used for watering this area.

In the GTU area, a plot approximately 90 feet by 300 feet was planted with fast-growing poplars and willows. Planting in the GTU area was completed in the fall of 2002. In order to prevent tree roots from coming into contact with the thermally treated ash, a hole was bored to native soil for each individual tree, and the borehole was lined with high-density polyethylene (HDPE) pipe. All of the GTU area trees were planted by lowering rooted whips to the bottom of the boring and then filling in the boring with a mixture of soil, sand, bark, and peat. A dedicated drip irrigation system was also installed within this plot.

In total, approximately 1,000 trees were planted at the LEU site, and it was estimated that for the 2003 growing season, the average tree took up approximately 210 gallons of groundwater. Multiplying this amount by the total number of trees, the approximate water uptake by both phyto remediation systems was 210,000 gallons of groundwater. The results of soil sampling for VOCs and chloride in 2004 and 2005 indicated that biodegradation was occurring in the PCE­contaminated area. Active biodegradation has been further supported by the results of groundwater samples collected at a nearby monitoring well, where a steady decrease in PCE cencentrations has been accompanied with a concurrent, steady increase in total 1,2­dichloroethene (total 1,2-DCE) concentrations. The GTU system has enhanced collection of the TeE groundwater plume. TCE concentrations in groundwater samples collected from nearby monitoring wells have declined, and TCE has not been detected off site in groundwater east of the site.

In order to optimize the remedy implementation, portions of the treated groundwater effluent was diverted to irrigate the phytoremediation plots from the discharge to the POTW. An ESD was signed on July 16, 2004, acknowledging the remedy enhancements and allowing this diversion of portions of the treated ground water effluent.

4.2.2.4 Institutional Controls

Institutional controls (lCs) are non-engineered instruments, such as administrative and or legal controls that help minimize the potential for exposure to contamination and protect the integrity of the remedy. Compliance with ICs is required to assure long-term protectiveness for those areas that do not allow for unlimited use or unrestricted exposure (UUIUE).

ICs were not required by the two RODs or the ESD documenting the required site remedies. No ICs are required for the soils since the Site remedies have achieved UUIUE for all Site soils. The groundwater at the Site is not anticipated to reach concentrations which would allow for UUIUE standards for many years. Groundwater use restrictions are necessary to prohibit usage of the groundwater until groundwater concentrations reach those levels which would allow for UUIUE throughout the plume. Therefore, EPA will modifY the remedy to include ICs until the groundwater standards are met. Currently, LaSalle City Ordinance # 1474 prohibits the constlUction of "any private water system including a well, within the City of LaSalle, for the

4-6

purpose ofobtaining a water supply" where the LaSalle public water supply is within 300 feet of the nearest property line. This prohibition would apply to all areas of the contaminated groundwater plume. The ordinance must be verified to be in place and effective and properly monitored. The contaminant plume area is located entirely within the City of LaSalle, and thus the public water supply must be used. IEPA examined the municipal water supply system and conducted a survey of private residential wells in the area and determined that the shallow groundwater is not currently used for potable purposes.

The table below summarizes institutional controls that are needed for the site.

Table 1 .. ns I U lona leton roIs 5ummary T bleft f a Media, Engineered Controls, & Areas that Do Not Support UU/UE Based on Current Conditions. Groundwater - current area that exceeds groundwater remedial action objectives

IC Objective

Prohibit groundwater use until cleanup standards are achieved

Title of Institutional Control Instrument Implemented (note if planned) City of LaSalle Ordinance # 1474

Current Compliance: Based on the Site inspection and data reviewed, neither rEPA nor U.S. EPA are aware of site or media uses which are inconsistent with of the objectives of the rcs. IEPA examined the municipal water supply system and conducted a survey of private residential wells in the area and determined that the shallow groundwater is not currently used for potable purposes. Therefore, at this time, the LaSalle City Ordinance appears to be functioning as intended. However, long term protectiveness requires compliance with effective lCs.

Long Term Stewardship: Long term protectiveness at the site requires compliance with use restrictions to assure the remedy continues to function as intended. To assure proper maintenance, monitoring and enforcement of effective rcs, long term stewardship procedures will be reviewed and an IC plan will be developed. The plan will identify the type and location of ICs which need to be implemented, what type of remedy modification is required, and specify monitoring efforts required to ensure the ICs remain in place and effective.

4-7

5 PROGRESS SINCE THE LAST FIVE-YEAR REVIEW

The previous Five-Year Review signed on September 27, 2004 stated the remedy as currently implemented at the LEU site is expected to be protective of human health and the environment upon attainment of the ground water cleanup goals, through continued operations ofthe GTU, dual phase SVE, and phytoremediation systems, which are expected to require approximately 10 mme years of operation. In the interim, exposure pathways that could result in unacceptable risks are being minimized by the groundwater gradient control established by the groundwater ccllection system and GTU.

Long-term protectiveness of the remedial action will be verified by obtaining additional groundwater samples to fully evaluate potential migration of the contaminant plume downgradient from the treatment area. Current data indicates that the majority of the plume remains on site. Semi-annual groundwater sampling will continue, and sampling of the GTU effluent will also be maintained to ensure compliance with the local POTW discharge requirements.

By thl~ end of 2004, the total mass of contaminants in the extracted groundwater was minimal arid approaching asymptotic levels. Upon completion of the LRTA in March 2005, Illinois EPA dc'cided to shut down the groundwater extraction, GTU, and SVE systems to allow long-term observation and assessment of contaminant rebound effects in groundwater. Through its final months of operation, the groundwater extraction system continued to facilitate capture and collection of groundwater, thereby reducing groundwater contaminant concentrations.

Shutdown of the GTU and SVE systems has not resulted in a significant increase in contaminant concentrations or in the areal extent of the 1,1,1-TCA and TCE plumes (see Figures 5-1 through 5-4). During the third Five-Year Review period, migration of the TCE plume along the more pt:rmt:able trench backfill material surrounding the groundwater collection system laterals was observed to the south. However, migration beyond the laterals appears to be limited due to the nati"t~ silty clay soils beyond the backfill. Groundwater flow across the site is to the south­south,~ast, as was observed prior to the operation of the GTU, and water levels have risen 12 to 15 fet:t since the GTU shutdown. The phytoremediation systems continue to operate, and analY1:ical results show that the trees are extracting and degrading VOC contamination. Semi­armua.l groundwater monitoring continues at the site to evaluate changes in the nature and extent of contaminant concentrations as well as changes in groundwater flow patterns.

Recommendations presented in the second Five-Year Review report were implemented. Hydrochloric acid flushing and hydraulic cleaning ofthe collection laterals was conducted to remove gypsum precipitate. A re-examination of the municipal water supply system and a survey of private residential wells in the area determined that shallow groundwater is not currently used for potable purposes and a prohibition ordinance is in place. LaSalle City Ordinance # 1474 prohibits the construction of "any private water system including a well, within the City of LaSalle, for the purpose of obtaining a water supply" where the LaSalle public water supply is within 300 feet of the nearest property line. This prohibition would apply to all areas of the contaminated groundwater plume. Are-evaluation of the risk assessment was conducted to determine the risks to human health and the environment that could occur after the

5-1

shutdown of the GTU and SVE systems. The RRA evaluated the risks associated with potential contaminated vapor intrusion into nearby residences and commercial buildings. The RRA is pending final Illinois EPA review and indicates that the potential maximum cancer risks and noncancer hazards were well below levels of potential concern. Groundwater at the site continues to be monitored to assess any further changes in site conditions that may result in risks to human health and the environment.

5-2

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5.7

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6 FIVE-YEAR REVIEW PROCESS

6..1 Administrative Components

The LEU site is a State-lead site. Illinois EPA contractors maintain the remedy systems, perform engirH:ering evaluations, and conduct groundwater monitoring. The RPM has prepared this Five­Year Review report using accumulated data and data submitted by the contractors in support of maintaining and monitoring the implemented remedy at the LEU site.

6.2 Community Involvement

The Illinois EPA maintains an office in LaSalle within 0.5 miles of the site. The same Illinois EPA RPM has managed this site since 1988, and is known in the community. As a result, local residents have relatively immediate access to the Illinois EPA and can discuss the site with the Illinois EPA RPM. Additionally, Illinois EPA maintains a repository at the local junior college serving LaSalle. While no specific meeting was held to notify the public that the Five-Year Rt:view process had been initiated, the continuous presence of the RPM in the community, as well as a local repository, has kept the public informed and allowed their questions and concerns to be addressed.

Upon acceptance and approval of this report by the U.S. EPA, the Illinois EPA will publish a notice in the local newspaper that the Five-Year Review report is available in the local repository.

6.3 Document and Data Review

The two phytoremediation systems are in operation, and semiannual groundwater monitoring continues to be conducted at the site. The following text provides an abbreviated summary of the mJst recent data and interpretations. A complete summary of the existing groundwater quality data can be found in the following document:

• Technical Memorandum, Groundwater Sampling Results, October 2006-March 2008. LaSalle Electric Utilities Site, dated July 2008.

Since the groundwater extraction system and GTU were taken off line in March 2005, the bt:ginning of this Five-Year Review period does include the final months of GTU operation (October 2004 to March 2005). The following text provides an abbreviated summary of the most recem data and interpretations related to the groundwater extraction system and GTU. A complete summary of these remedial systems operations can be found in the following document:

• Review and Assessment Report, LaSalle Electric Utilities Company Site, Groundwater Treatment Unit, January 2004-March 2006, dated June 2006.

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6.3.1 Groundwater

VOC concentrations in monitoring wells, piezometers, and most manholes continued to decline or remained steady during 2006,2007, and 2008. VOC concentrations during these years were generally less than those observed in 2004 and 2005. Of the 19 available monitoring wells and piezometers, five indicated VOCs at concentrations above MCLs during at least one sampling event conducted in 2006 through 2008. At the perimeter of the site, VOCs were either not detected, or were consistently detected at concentrations below their respective MCLs during these sampling events.

The absence of a groundwater capture zone and discontinued irrigation of the phytoremediation trees in the GTU area results in a south-southeast flow direction across the site, as was observed prior to the operation of the GTU. Groundwater typically enters the site from the north or northwest and flows to the east across St. Vincent Avenue or to the south across 24th Street where it continues to be influenced by the 60-inch storm sewer. At the collection system manholes, water levels have risen 12 to 15 feet since the collection system shut down in 2005.

Maps showing the annual mean 1, I,1-TCA and TCE concentrations in groundwater in 2004­2005 and 2008-2009 are provided in Figures 5-1 through 5-4. As depicted in these figures, the shutdown of the groundwater extraction system and GTU has not resulted in a significant increase in contaminant concentrations or in the areal extent of the 1,1,1-TCA and TCE plumes. One notable change is the migration of the TCE plume along the more permeable trench backfill material surrounding the groundwater collection system laterals to the south. However, migration beyond these laterals appears to be limited due to the native silty clay soils beyond the backfill. This is supported by the results of groundwater samples collected from monitoring wells south of the site and downgradient of the southernmost collection system laterals, where TCE concentrations were either below the MCL or not detected.

VOC concentrations in the Laboratory area and Thinner Shed area extraction wells, EW12 and EW3, respectively, have remained relatively steady during the shutdown. Limited analytical data exists to accurately assess the positive impacts of the dual-phase SVE system during its final months of operation. For the phytoremediation systems, analytical data collected in the PCE­contaminated Northwest source area has shown that contaminant extraction and degradation has occurred. Active biodegradation has been further supported by the results of groundwater samples collected at a nearby monitoring well, where a steady decrease in PCE concentrations has occurred concurrently with a steady increase in totall,2-DCE concentrations. The phytoremediation system east of the GTU has enhanced collection of the TCE groundwater plume. TCE concentrations in groundwater samples collected from nearby perimeter monitoring wells have declined and TCE has not been detected in groundwater east of the site.

6.3.2 Groundwater Treatment Unit

During the final months of operation under this Five-Year Review period, the GTU was operated by a "K" class operator, licensed by the State of Illinois, and discharge from the GTU was via a permit issued by the City of LaSalle for discharge to the city sanitary sewer. Compliance with the operating permit requirements was on a self-monitoring basis. The permit required that the

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operawr of the GTU collect weekly effluent samples and analyze them for PCBs and 16 VOCs. Conthuous measurement of effluent pH was also required by the permit to ensure that certain pH limitations were met prior to discharge. Permissible discharge criteria for PCBs and VOCs Wi~re based on 1990 drinking water MCLs as required in the March 1988 ROD.

During the final months of operation, the GTU continued to be operated in batch mode to maximize the achievable drawdown while maintaining pump protection. The total volume of water processed since the GTU became fully operational in April 1993 was 44,912,095 gallons. The GTU has removed an estimated total of343 pounds ofVOCs from groundwater since the inception of treatment in 1993. During the final months of operation, weekly effluent PCB and V~OC concentrations never exceeded their respective discharge criteria.

During the final months of operation, the main VOC treated by the plant was 1,1,1-TeA. The VOC influent load was composed of 1,1,1-TCA (68%), l,l-DCA (14%), TCE (11%), and 1,2­DCE (7%). These results indicate that the major contributor ofVOC volume into the system continued to be the Laboratory plume located along the southeastern portion of the site. This plum{: and associated source area were identified and delineated during the Phase I and Phase II soil investigations conducted in 1996 and 1998. Other VOC plumes and source areas, including the Thinner Shed source area and the Northwest area plume, contributed to influent concentrations to a lesser degree than the Laboratory plume area.

6.4 Site Inspection

The U.S. EPA Region 5 RPM visited the site on August 31, 2009 in support of this Five-Year Review and was accompanied by the Illinois EPA RPM. At that time, site conditions were assessed. The site was in generally good condition. Since the Illinois EPA RPM is based within 0.5 miles of the site, state presence at the site is frequent. Specific deficiencies were not noted by either the Illinois EPA RPM or the U.S. EPA RPM.

6.5 Interviews

Giv{:n the Illinois EPA office in LaSalle, questions and/or concerns from local residents are addressed in a timely fashion. Therefore, specific interviews associated with the preparation of the Five-Year Review report were not conducted.

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7 TECHNICAL ASSESSMENT

Question A: Is the remedy functioning as intended by the decision documents?

NO.

The contaminated soils and sediments were excavated and permanently treated as required by the OUI and OU2 RODs to levels that allow for UU/UE by 1994. In terms ofthe groundwater for the LEU site, GTU and SVE systems were functioning as intended by the OU2 ROD. However after the long-term aquifer rebound observational period. the operations were not re-started due to budgetary reasons. Consequently, the GTU and SVE systems must be re-started in order for the remedy to function as intended

Remedial Action performance: As shown in Figures 5-1 through 5-4, the shutdown of the GTU and SVE systems has not resulted in a significant increase in contaminant concentrations or in the areal extent ofthe 1,1,1-TCA and TCE plumes. One notable change is the migration of the TCE plume along the more permeable trench backfill material surrounding the groundwater collection system laterals to the south. However, groundwater contaminants have not impacted the native silty clay soils screened by the perimeter monitoring wells. The phytoremediation system continues to degrade contaminants in the PCE-contaminated Northwest source area, and the GTU area system has enhanced collection of the TCE groundwater plume, preventing contaminant migration east of the site. Groundwater at the site continues to be sampled semiannually to monitor any changes in contaminant concentrations, as well as to determine changes in groundwater flow patterns. Based on groundwater analytical data, additional groundwater extraction and treatment will be necessary to achieve the remedial action objectives (RAOs; i.e., MCLs) currently established for the site. The RAOs for groundwater are to remove contaminants from the groundwater to achieve the MCLs for the VOC contaminants and I ppb for PCBs.

System operations/operation and maintenance (0 & M): The GTU and SVE systems were shut down due to allow long-term observation and assessment of contaminant rebound effects in groundwater upon termination of the LTRA. Prior to this, the remedy was functioning as intended. However, due to Illinois EPA budgetary issues, the systems have not been re-started. The long-term observational period is complete and the groundwater extraction system, GTU, and SVE systems need to be restarted as soon as reasonably possible to ensure the remedies remain protective. Groundwater at the site is sampled semiannually to monitor any changes in contaminant concentrations, and water levels are measured to determine any changes in groundwater flow patterns. The phytoremediation plots are inspected on a monthly basis, and the vegetated cover is maintained as needed. Illinois EPA has retained a group of qualified contractors whose familiarity with the remedy and its enhancements allows for timely 0 & M activities and troubleshooting when necessary.

Implementation of institutional controls and other measures: The GTU and SVE systems are located within fenced areas. No break-ins have occurred, which is supportive of no additional security being required. The vegetated soil cover over the thermally treated soil is

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well maintained and there is no apparent burrowing by small animals into the ash. While most of phytoremediation plantings are not within a secured area, vandalism has not been noted. Similarly, monitoring wells and manhole standpipes are not within a secured area; however, they are secured by locks and vandalism has not been noted. Therefore, no additional security measures are needed at the LEU site.

No institutional controls were included in either of the RODs or the ESD. The City of LaSalle has ,ill ordinance restricting the use of the shallow groundwater preventing unacceptable exposures. The ordinance must be verified to be in place and effective, and compliance with the ordin:mce must be monitored. Also, EPA will revise the remedy revision is required to include les until the groundwater standards are met.

Monitoring activities: Semi-annual groundwater monitoring continues at the site. This monitoring includes sample collection to monitor any changes in contaminant concentrations, and water level measurements to determine any changes in groundwater flow patterns. During the final months of operation, GTU effluent samples were analyzed on a weekly basis for VOCs arId PCBs to ensure ongoing compliance with discharge limitations. No exceedances of discharge limitations were observed. The monitoring plan needs to be reviewed and updated as appropriate to fully evaluate the impacts of the extended observational period. The plan should also include provisions to verify the ordinance prohibiting shallow groundwater use remains in effect.

OImQrtunities for optimization: Currently, the phytoremediation plots continue to provide groundwater contaminant extraction and treatment for portions of the site. In order to achieve the current RAOs (i.e., MCLs) established for the site, additional groundwater extraction and treatment will be necessary. Furthermore, additional efforts to address residual contamination in the source areas will be necessary. Should funding be obtained, residual contamination can be addressed by restarting the SVE system; however, groundwater extraction likely will be m~cessary to dewater these source areas in order to make this remedy enhancement effective.

Early indicators of potential remedy problems: As groundwater monitoring is conducted semi-annually, analytical results are the primary indicator of potential remedy problems. Continued groundwater monitoring will be conducted to assess changes in site conditions that may result in risks to human health and the environment.

Queslion B: Are the exposure assumptions. toxicity data. cleanup levels. and RAGs used at the time ofthe remedy selection still valid?

Yes.

RAO;; in the ROD are based on groundwater MCLs for VOC contaminants and a level of I ppb f(lr PCBs. A re-examination of the municipal water supply system and a survey of private wells in the area determined that shallow groundwater is not currently used for potable purposes and a prohibition ordinance is in place. Additionally, the draft RRA concluded that the potential maximum cancer risks and noncancer hazards associated with potential contaminated vapor intm~,ion into nearby residences and commercial buildings were well below levels of potential

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concern. Based on this data, the Illinois EPA is evaluating if alternate concentration limits may be appropriate for the site. Alternate RAOs for the site would require a modification to the remedy specified in the OU2 ROD as modified by the ESD.

Question C: Has any other infOrmation come to light that could call into question the protectiveness ofthe remedy?

No.

Based on the analytical data, the remedy is currently protective. Continued groundwater monitoring will be conducted to assess any further changes in site conditions that may result in risks to human health and the environment. No additional information has been obtained to indicate that the remedy is insufficient.

Technical Assessment Summary

The GTU and SVE systems were shut down to allow for long-term observations of the rebound of the aquifer. Although these systems have not yet been re-started, this has not resulted in a significant increase in contaminant concentrations or in the areal extent of the 1,1,1-TCA and TCE plumes, and one remedy enhancement, the phytoremediation plots, continues to provide groundwater contaminant extraction and treatment at the site. There is no evidence of current exposure and the City of LaSalle has an ordinance which prohibits the use of the shallow groundwater. Semiannual groundwater monitoring is conducted at the site to assess any changes in site conditions that may result in risks to human health and the environment. Based on the groundwater analytical data, the remedy is currently protective of human health and the environment; however, additional groundwater extraction and treatment will be necessary to achieve the RAOs (i.e., MCLs) currently established for the site. Based on the results ofthe draft RRA, alternate RAOs for the site may also be considered by the Illinois EPA.

The remedies implemented at the site are protective of human health and the environment in the short term because:

• Contaminated soils, sediments, and debris have been excavated and treated on-site or disposed appropriately off-site;

• The contaminated buildings on-site were demolished and removed for off-site disposal and other affected structures were industrially cleaned where significant excavation of contaminated soil was conducted;

• A groundwater extraction and treatment system was constructed, the contaminated groundwater plume had been captured by the operating system, and was enhanced by the addition of two dual-phase SVE units and two phytoremediation plots to target isolated source areas and to minimize the amount of clean water collected and treated; and

• There is no evidence of exposure to the contaminated ground water.

However if the groundwater extraction system and GTU are not re-started, the remedy specified in the OU2 ROD will not be operating and functioning as intended and the long-term protectiveness of the remedy will be threatened.

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8 ISSUES

A reduction in groundwater volume collected by the system was observed during the second Five-Year Review period. This reduction was attributed to partial clogging of the collection laterals with gypsum precipitate, and limited hydraulic cleaning and mild acid flushing of segments of the collection laterals were successful in removing those blockages. During the third Five-Year Review period, the Illinois EPA retained a subcontractor to hydraulically clean the entire groundwater collection system. The effectiveness of the cleaning could not be fully evaluated since the GTU system was shut down approximately one month after the collection system was cleaned. Once the GTU and SVE systems shut down in March 2005, there were no further 0 & M issues related to these systems. No a & M issues have occurred with regards to the phytoremediation plots or the semiannual groundwater monitoring activities.

The DJllowing issues have been identified that may prevent the remedy from being protective:

I). The groundwater extraction, GTU, and SVE systems have been shut down for an observational period but have yet to be restarted;

2). Groundwater monitoring may need to be modified to fully understand the current conditions of the aquifer due to the extended shutdown period; and

3). Institutional controls are not included in the au 2 ROD or the ESD for the site which would prevent exposure to contaminated groundwater until the aquifer is restored to beneficial reuse. However, a LaSalle City Ordinance currently prohibits the use of the shallow groundwater. This ordinance needs to be evaluated to ensure additional controls are not necessary.

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9 RECOMMENDATIONS AND FOLLOWUP ACTION

Based on the groundwater monitoring data collected during this Five-Year Review period, shutdown of the GTU and SVE systems has not resulted in a significant increase in contaminant concentrations or in the areal extent of the 1,1,1-TCA and TCE plumes. One notable change is the migration of the TCE plume along the more permeable backfill surrounding the groundwater collection laterals to the south. However, migration beyond the laterals appears to have been limited by the native silty clay soils beyond the backfill.

The analytical results indicate that the phytoremediation system in the PCE-contaminated Northwest source area is extracting and degrading VOC contamination, and the GTU area system has enhanced collection of the TCE groundwater plume. However, the cleanup objectives currently established in the ROD for the LEU site have not yet been met, and the shutdown of the GTU and SVE systems will not reduce the overall time frame for meeting the RAOs established for the site. There currently are no immediate threats. Semiannual groundwater monitoring should be conducted through the next Five-Year Review period to evaluate any changes in the nature and extent of site-related contaminants, as well as any changes in groundwater flow patterns, that may result in risks to human health and the environment.

A re-examination of the municipal water supply system and a survey of private wells in the area determined that shallow groundwater is not currently used for potable purposes. The City of LaSalle has an ordinance prohibiting use of shallow groundwater. Are-evaluation of the risk assessment was conducted to determine the risks to human health and the environment that may occur after the shutdown of the GTU and SVE systems. The draft RRA evaluated the risks associated with potential contaminated vapor intrusion into nearby residences and commercial buildings. The document is pending final Illinois EPA review; however, the results indicated that the potential maximum cancer risks and noncancer hazards were well below levels of potential concern. Based on these results, the Illinois EPA is evaluating if alternate concentration limits may be appropriate for the site.

Table 2. Recommenda fIOnsIF0 II Afow-up C Ions

Recommendation/Follow-upAction Party

Responsible

Projected Milestone

Date

Affects Protectiveness

Current Future

Develop plan to re-start the groundwater extraction, GTU, and SVE systems Illinois EPA 12/31/09 N Y

Update the groundwater monitoring requirements to fully evaluate the Illinois EPA 12/31/09 N Y extended shutdown observational oeriod Develop an IC Plan to determine: which ICs are necessary until the groundwater RAOs are achieved; the necessary remedy modifications to include the ICs;

Illinois EPA 12/31/09 N Y

and to specify the requirements needed to monitor whether the ICs remain effective.

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"~--__________ __II.__

10 PROTECTIVENESS STATEMENT

Long··tenn protectiveness of the remedial action will be verified by continuing semiannual groundwater sampling in order to assess any further changes in site conditions that may result in ri~;ks to human health and the environment. Although shutdown of the GTU and SVE systems has occurred. the phytoremediation plots continue to extract and treat groundwater contaminants at the site. Based on the groundwater analytical data collected during this Five-Year Review period, the remedy is currently protective, and based on the results of the draft RRA, there currertly are no immediate threats. The protectiveness for each au and on a site-wide basis is as follows:

au 1- Remedy is protective.

aU2 -. Remedy is protective in the short tenn because there is no evidence that there are current exposures. In order for the remedy to remain protective in the long tenn, the groundwater extraction, GTU, and SVE systems must be re-started and the LaSalle City ordinance prohibiting us{~ of the shallow groundwater must be verified and monitored.

Sitl~ wide - The remedies implemented at the site for the entire site are protective in the short tenn because there is no current exposure. In order for the remedies to remain protective in the long tenn, the groundwater extraction, GTU, and SVE systems must be re-started Additionally, long te:nn protectiveness requires compliance with effective institutional controls until the cle,mup standards have been met. A LaSalle City ordinance exists to prohibit construction of any private wells for the purpose of obtaining a water supply. Compliance with effective institutional controls will be ensured by: verifying the existence of the ordinance; reviewing its effectiveness; and ensuring the ICs are monitored, maintained and enforced. Finally, the remedy will be modified, if necessary, to fonnally incorporate the ICs.

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11 NEXT REVIEW

The next Five-Year Review for the LEU site is required by September 2014, five years from the date of this review.

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