Screening-Level Ecological Risk AssessmentA SLERA performed in 2003 using surface water and sediment analytical data collected from the Rumford River indicated the presence of potential

Screening-Level Ecological Risk Assessment(Vernal Pools)

Addendum to the Baseline Ecological Risk Assessment

Hatheway & Patterson Superfund SiteMansfield, Massachusetts

Prepared for:

U.S. Environmental Protection Agency Office of Environmental Measurement and Evaluation US EPA - Region I 11 Technology Drive North Chelmsford, Massachusetts 01863

Prepared by:

Lockheed Martin Information Technologies Environmental Services Assistance Team, Region I The Wannalancit Mills, 175 Cabot Street, Suite 415

Lowell, MA 01854 Phone: (978) 275-9730

Faxsimile: (978) 275-9489

March 2005

Hatheway & Patterson Superfund Site Mansfield, MA

SLERA (Vernal Pools) March 2005

TABLE OF CONTENTS EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

RISK ANALYSIS AND CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.0 SITE DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 NON-PERMANENT AQUATIC HABITATS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1.1 Environmental receptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1.1.1 Aquatic invertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1.1.2 Amphibians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.0 DATABASE DEVELOPMENT AND DATA PROCESSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.1 DATA SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.2 DATA QUALITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SECTION 3: PROBLEM FORMULATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1 SITE CHARACTERIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1.1 Site exposure unit (EU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1.2 Background EU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.2 SELECTING CONTAMINANTS OF CONCERN (COCs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2.1 Surface water benchmarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2.2 Sediment benchmarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2.3 Media-specific COCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.2.3.1 Surface water COCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2.3.2 Sediment COCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.3 SCREENING-LEVEL CONCEPTUAL SITE MODEL (CSM) . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3.1 Exposure pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4 SCREENING-LEVEL ASSESSMENT AND MEASUREMENT ENDPOINTS . . . . . . . . . . . . . 7 3.4.1 Selecting representative assessment endpoint species or communities . . . . . . . . 8 3.4.2 Assessment endpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.4.3 Measurement endpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.4.3.1 Water column community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.4.3.2 Benthic macoinvertebrate community . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.0 ECOLOGICAL EXPOSURE ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5.0 ECOLOGICAL EFFECTS ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11



5.1 Surface water benchmarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5.2 Sediment water benchmarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

6.0 ECOLOGICAL RISK CHARACTERIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6.2 ASSESSMENT ENDPOINT 1: WATER COLUMN COMMUNITY . . . . . . . . . . . . . . . . . . . . 12

6.3 ASSESSMENT ENDPOINT 2: BENTHIC INVERTEBRATE COMMUNITY . . . . . . . . . . . . . 13

6.4 UNCERTAINTY ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.4.2 Uncertainties associated with assessing risk to water column organisms . . . . . . 14 6.4.3 Uncertainties associated with assessing risk to benthic invertebrates . . . . . . . . . 14

7.0 SUMMARY AND CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

8.0 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figures:

Figure 1: Habitat areas

Figure 2: Vernal pool locations

Figure 3: Conceptual site model - vernal pools

Attachments:

Attachment 1: Selection of surface water COCs in two vernal pools

Attachment 2: Selection of sediment COCs in two vernal pools

Attachment 3: Summary of COCs in surface water and sediment from two vernal pools

Attachment 4: Potential risks associated with surface water in two vernal pools

Attachment 5: Potential risks associated with sediment in two verbal pools

LIST OF ACRONYMS

AST aboveground storage tanks AVS acid volatile sulfides BERA baseline ecological risk assessment COC contaminant of concern CSM conceptual site model DNAPL dense non aqueous phase liquid EPA Environmental Protection Agency ER-L effects range - low ER-M effects range - median Eq-P equilibrium partitioning ET ecotox threshold EU exposure unit HPSS Hatheway & Patterson Superfund Site HQ hazard quotient LCV lowest chronic value LEL lowest effect level NAWQC national ambient water quality criteria PAH polycyclic aromatic hydrocarbon PCP pentachlorophenol SCV secondary chronic value SEL severe effect level SEM simultaneously extracted metal SLERA screening-level ecological risk assessment SVOC semivolatile organic compound UST underground storage tanks





EXECUTIVE SUMMARY

INTRODUCTION

A screening-level ecological risk assessment (SLERA) was performed to assess the potential for ecological risk in two vernal pools at the Hatheway & Patterson Superfund Site (the Site). The Site was used for several decades as a wood treatment facility until its closure in 1993. Starting in the early 1970's, seeps were found discharging contaminated groundwater along a section of the Rumford River flowing through the Site. During subsequent investigations, high levels of wood treatment chemicals (principally heavy metals, polycyclic aromatic hydrocarbons [PAHs] and phenolic compounds) were detected in the sediments and surface water of the Rumford River.

The Hatheway & Patterson Company declared bankruptcy in 1993. Remedial activities since that time have included building a retaining wall and installing pumping equipment downgradient from the historic drip pads to limit the transfer of contaminated groundwater into the river.

A SLERA performed in 2003 using surface water and sediment analytical data collected from the Rumford River indicated the presence of potential ecological risk to benthic invertebrates and fish in the river at the Site. A subsequent baseline ecological risk assessment (BERA) was performed to better quantify the extent of this hypothetical risk. It concluded that actual risk to aquatic receptors (specifically, benthic macroinvertebrates, water column invertebrates, and fish) and fish-eating wildlife receptors (specifically, great blue heron and mink) were minimal to non-existent.

The current SLERA is an addendum to the BERA. The goal of this SLERA was to determine what potential risk, if any, may be associated with contaminants detected in surface water and sediment samples collected from two vernal pools at the Site.

RISK ANALYSIS AND CONCLUSION

The risk analysis for the vernal pool SLERA was based on a single surface water and sediment sample collected from each of two vernal pools at the Site (specifically, VP-C2 and VP-D1). The first step consisted of developing a screening-level problem formulation to select COCs, and develop a conceptual site model (CSM) to describe exposure pathways, identify potential receptors of concern, and select assessment and measurement endpoints. The receptors of concern for the vernal pools included benthic invertebrates, water column invertebrates, and the aquatic life stages of amphibians (i.e., tadpoles). Fish were omitted because the vernal pools have no permanent connection to the Rumford River and also dry out in the summer.

The SLERA was expanded to better quantify potential risk by calculating hazard quotients (HQs) for those COCs which exceeded their chronic surface water benchmarks and “no effect” sediment benchmarks. The evidence indicated that the potential for surface water risk was present in both vernal pools based on high levels of metals, and in VP-C2 based on high levels of PCP (HQ = 45.3). It was noted that the metals with the highest HQs (specifically, aluminum, iron, and mercury) were not associated with past activities at the site and might therefore represent background conditions.

The analysis showed that potential risk for metals in sediment was present in VP-D1, but only when evaluated using the “no effect” benchmarks. This potential risk became insignificant when evaluated using the “effect” benchmarks (i.e., all “effect” HQs < 1.0). Metals were not associated with risk in VP-C2 sediment. This evidence suggested that metals (at least those with benchmarks) were not risk drivers in vernal pool substrates.

1



All SVOCs exceeded their “no effect” sediment benchmarks in VP-D1. The potential risk from SVOCs (with the exception of PCP with a “no effect” HQ = 2.2, but for which an “effect” benchmark was not available) became insignificant when evaluated using “effect” benchmarks (i.e., all “effect” HQs < 1.0).

All SVOCs also exceeded their “no effect” sediment benchmarks in VP-C2. The potential risk from SVOCs, with the exception of PCP (“no effect” HQ = 1,920, but for which an “effect” benchmark was not available), fluorene (“effect” HQ = 1.8), and 2-methylnaphthalene (“effect” HQ = 3.6), became insignificant when evaluated using “effect” benchmarks (i.e., HQs < 1.0). PCP was by far the biggest risk driver in VP-C2. With such a high HQ, it is reasonable to expect toxicity in the sediment from VP-C2.

The potential risk associated with VP-D1 could be confirmed or denied by conducting a surface water toxicity test. This could be performed reasonably easily as part of pre-design work to help refine the available information on the areas requiring remediation in the general vicinity of VP-D1.

VP-C2 has a greater likelihood of presenting actual risk, based on the high PCP HQ at this location. Further, this vernal pool may have a direct connection to a PCP plume that originates on-site. This would suggest that dredging the sediment from VP-C2 would do little to reduce risk, as new PCP would reenter the vernal pool from groundwater. An alternative might be to re-create this vernal pool in a nearby area containing a high water table not impacted by a PCP plume. If appropriate and relevant, clean soil could also be used to fill VP-C2 to eliminate exposure to PCP by aquatic receptors at that location in the future.

2



1.0 SITE DESCRIPTION

A detailed description of the environmental setting at the Site was provided in the BERA. The reader is referred to Chapter 2 of the BERA for additional details. Figure 1 (from M&E, 2002) in this SLERA provides a general overview of the Site and its major terrestrial habitats. The brief description below refers specifically to the vernal pools at the Site.

1.1 NON-PERMANENT AQUATIC HABITATS

Vernal pools are formed in shallow depressions on the ground surface which fill up with runoff from snow melt and spring rains or are created in response to a rising groundwater table resulting from snow melt or spring rain. Several characteristics are common to vernal pools:

• small size: the surface area rarely exceed 0.1 acres • shallow depth: depths are usually less than 3 ft • isolated from permanent water: no fish predation • temporary: most vernal pools dry up by late spring-early summer

Many aquatic invertebrates and amphibians take advantage of these temporary habitats for breeding in the spring. Tadpole survival is enhanced due to the lack of fish predation. However, reproduction and development must be completed in a few weeks before the pool dries up and the aquatic habitat disappears.

A field survey conducted March 29 and April 1, 2002, identified eight vernal pools in the palustrine forested areas of the Site. Figure 2 (from M&E, 2002) in this SLERA depicts the location of those vernal pools. It should be noted that VP-D3 and VP-D4 in “Area C” (south of the Rumford River) appear to have been mislabeled in Figure 2 and should instead have been listed as VP-C3 and VP-C4, respectively. Also, Figure 2 indicates that VP-D3 in “Area D” (north of the Rumford River) appears to have been split into three separate locations (VP-D3W, VP-D3S, and VP-D3E, respectively) for reasons not explained in M&E (2002).

1.1.1 Environmental receptors

1.1.1.1 Aquatic invertebrates

Vernal pools, when present, offer habitat to numerous (semi-)aquatic invertebrates, including diving beetles, dragon flies, damsel flies, water boatman, back swimmers, water striders, oligochaetes, leeches, chironomids, and amphipods, among others. Some species are opportunists who use the pools as temporary feeding stations. Others use the pools for reproduction.

1.1.1.2 Amphibians

Vernal pools represent a critical habitat for many amphibians (frogs, toads, salamanders) with aquatic life stages. Reproductive success can be greatly enhanced by breeding in waters where fish predation is nonexistent.

3



2.0 DATABASE DEVELOPMENT AND DATA PROCESSING

2.1 DATA SOURCES

On April 25, 2002, a single surface water sample and sediment sample was collected from each of two vernal pools at the Site (for details, see M&E, 2002). Surface water and sediment samples were not collected from the other six vernal pools because they no longer contained enough water to serve as amphibian breeding habitat.

• The first pool (VP-C2), located in a depression created by a tree blowdown, was situated near the mouth of the Back Channel, about 300 ft downgradient from the former drip pads. Historically, a groundwater plume contaminated by wood preservatives from the former drip pads is believed to have moved in the general direction of VP-C2. When first surveyed on April 1, 2002, this pool was about 27 ft long by 7 ft wide, with a maximum depth of 1.0 ft. By April 25, 2002, VP-C2 had dried to 6 ft by 2.4 ft across and 0.5 ft deep.

• The second pool (VP-D1) was located in the palustrine forested area across from the Rumford River. There is no known hydraulic connection between this pool and the drip pads across from the river. When first surveyed on March 29, 2002, VP-D1 was about 30 ft long by 18 ft wide, with a maximum depth of 1.5 ft. By April 25, 2002, VP-D1 had dried to 28 ft by 16 ft across and 0.8 ft deep.

2.2 DATA QUALITY

The analytical data for the two surface water and two sediment samples collected from both vernal pools were validated prior to their release by M&E (2002). Only data without a flag or flagged with a “J” were retained for evaluation. Also, the surface water samples were not filtered prior to analysis. Hence, the metals data used in the SLERA represent total metals.

The analytical data were not summarized and summary statistics were not calculated because each vernal pool was considered as an individual habitat. Besides, only a single surface water and sediment sample was collected from each pool for analysis, precluding the use of summary statistics.

4



SECTION 3: PROBLEM FORMULATION

3.1 SITE CHARACTERIZATION

3.1.1 Site exposure unit (EU)

Each vernal pool represented its own EU to characterize exposure to aquatic invertebrates and amphibians in the SLERA.

3.1.2 Background EU

No background data collected from off-site vernal pools were available for comparison to the two on-site vernal pools. Hence, the assessment proceeded strictly based on the data obtained from the two vernal pools at the Site.

3.2 SELECTING CONTAMINANTS OF CONCERN (COCs)

COCs are a subset of the analytes present in site media which have the potential to affect local ecological receptors. The COCs were selected by comparing measured analyte concentrations in surface water and sediments to conservative published surface water and sediment screening benchmarks. An analyte in surface water or sediment was retained as a COC if its detected concentration exceeded its benchmark. Also, an analyte detected in surface water or sediment was automatically retained as a COC if it did not have a corresponding screening benchmark. Two analytes (acetophenone and diethyl phthalate) were eliminated because they were present in laboratory blanks. Finally, calcium, magnesium, potassium, and sodium were automatically eliminated as potential COCs because they are essential physiological electrolytes.

3.2.1 Surface water benchmarks

The published sources of screening benchmarks used in selecting surface water COCs for the vernal pools are described below. The order of preference (from highest preference to lowest preference) for selecting benchmarks was as follows:

• Chronic freshwater national ambient water quality criteria (NAWQC) presented in U.S. EPA (2002).

• Secondary Chronic Values (SCVs) calculated based on the Tier II method described in U.S. EPA (1995) as reported in Table 1 in Suter and Tsao (1996).

• The most conservative lowest chronic values (LCVs) for fish, aquatic invertebrates, or aquatic plants as reported in Table 1 in Suter and Tsao (1996).

The chronic NAWQC in U.S. EPA (2002) represent concentrations of analytes in surface water which, if not exceeded for four consecutive days over a three-year period, are not expected to cause unacceptable harm to freshwater aquatic organisms. The SCVs were developed with a methodology similar to that used for the NAWQC, except that they are based on a less complete data set than required for calculating the NAWQC. The missing toxicity data are compensated for by applying conservative correction factors. The LCVs represent the lowest published chronic toxicity data points found for fish, aquatic invertebrates, and aquatic plants by Suter and Tsao (1996).

3.2.2 Sediment benchmarks

The published sources of screening benchmarks used in selecting sediment COCs are described

5



below. The order of preference (from highest preference to lowest preference) for selecting the benchmarks was as follows:

• Consensus-based threshold effects concentrations (TECs) presented in Table 1 in Ingersoll et al. (2000).

• Effects Range - Low (ER-L) threshold concentrations presented by Long et al., (1995). • Ecotox thresholds (ETs) for sediments presented in Table 2 in U.S. EPA (1996); within this

table, the order of preference was freshwater sediment quality criteria, sediment quality benchmarks, and ER-L.

• Lowest effect level (LEL) Ontario provincial sediment quality guidelines (Persaud et al., 1993).

• For organic compounds, the Equilibrium Partitioning (EqP)-derived secondary chronic value or lowest chronic value sediment quality benchmarks presented in Table 3 in Jones et al. (1997).

• For pentachlorophenol (PCP), the marine sediment quality standard published by the Washington Department of Ecology (1991) was used.

TECs represent values below which harmful effects to benthic invertebrates are unlikely to be observed. ER-Ls are concentrations measured in estuarine or marine environments below which toxicity to benthic invertebrates rarely occurred. ETs were developed by the EPA as benchmarks for use as screening tools within the Superfund program. They were obtained from diverse sources, some of which include the ones described above. LELs represent values below which no effects are expected for the majority of sediment dwelling organisms. The Eq-P-derived benchmarks are values calculated using protective water quality criteria together with correction factors to account for the effects of organic carbon in sediment. The marine sediment quality standard for PCP represents a concentration at which no acute or chronic adverse effects are expected to biological resources. It was the only sediment criterion found for PCP. All the criteria listed above represent concentrations expected to protect benthic organisms.

3.2.3 Media-specific COCs

3.2.3.1 Surface water COCs

Attachment 1 presents the results of the COC selection process for the two surface water samples collected from the vernal pools at the Site. Seven metals and eight SVOCs were identified as COCs.

• All seven metals were retained because they exceeded their respective benchmarks in one or both vernal pools.

• Of the eight SVOCs identified as COCs, all but one were retained because they had been detected in one or both surface water samples but lacked corresponding benchmarks. Only PCP was detected in VP-C2 at a concentration far in excess of its published benchmark.

3.2.3.2 Sediment COCs

Attachment 2 presents the results of the COC selection process for the two sediment samples collected from the vernal pools at the Site. Nine metals and 16 SVOCs were identified as COCs.

• All but three of the nine metals identified as COCs were retained because they were detected in one or both sediment samples from the vernal pools but lacked corresponding benchmarks. The exceptions were copper, cadmium, and lead in VP-D1 which were retained because their

6



concentrations exceeded their benchmarks.

• Of the 16 SVOCs identified as COCs, all but five were retained because they were detected in one or both surface water samples at concentrations above their corresponding benchmarks. Of note was PCP which was present in the sediment sample from VP-C2 at a concentration over three orders of magnitude above its benchmark.

Attachment 3 provides a summary of the COCs identified in the surface water and sediment samples collected from the two vernal pools at the Site.

3.3 SCREENING-LEVEL CONCEPTUAL SITE MODEL (CSM)

A screening-level CSM identifies the sources, media, exposure pathways and receptors evaluated in the SLERA, and the relationship between the assessment and measurement endpoints. Its purpose is to illustrate how ecological receptors might come in contact with COCs associated with releases from the site. Figure 3 presents a simplified CSM for the vernal pools.

In the past, wood preserving chemicals were stored and used at various locations at the Site. Chemicals reached the groundwater table either directly via leaking underground storage tanks (USTs) or aboveground storage tanks (ASTs), or indirectly by migrating through the unsaturated soil column as a result of surface or subsurface spills and wood drying activities. Contaminants were transported downgradient in the groundwater and could have seeped into one or more low-lying depressions during times when the local water table was high. Alternatively, some of the contaminants could have reached the depressions as overland runoff during periods of heavy rainfall. The contaminants remained associated with sediments in those depressions when the pools dried out. Subsequent replenishment with water may cause some of those contaminants to resolubilize in the water column.

3.3.1 Exposure pathways

Various aquatic invertebrates and the aquatic life stages of certain amphibian species can be expected to use the vernal pools at the Site when they fill up with water in early spring. These aquatic organisms are exposed to contaminants either through direct contact with surface water, sediment, pore water and/or by ingesting surface water, sediment, pore water, and food items.

• Organisms exposed primarily via direct contact with surface water include water column invertebrates and the early life stages of amphibians swimming in the water column.

• Organisms exposed primarily to contaminants via direct contact with sediment or pore water include benthic invertebrates which spend their whole life in and on sediments (e.g., oligochaetes, amphipods) or juvenile life stages of terrestrial insects (e.g., stone flies, chironomids, mayflies, dragonflies).

• Organisms exposed primarily to contaminants via food ingestion may include larger benthic invertebrates such as predatory diving beetles and tadpoles.

3.4 SCREENING-LEVEL ASSESSMENT AND MEASUREMENT ENDPOINTS

Endpoints help quantify the risks to representative ecological receptors that may be exposed to site contaminants associated with the vernal pools. The first step was to select appropriate assessment endpoints which represent explicit expressions of the key ecological resources to be protected. They generally reflect

7



the protection of sensitive populations, communities, or trophic guilds.

Most often, it is not possible to directly quantify risk to an assessment endpoint. Instead, one or more measurement endpoints need to be selected for each assessment endpoint. These endpoints represent measurable ecological characteristics, quantified through laboratory or field experimentation, which can be related back to the valued ecological resources chosen as the assessment endpoints. To be relevant and useful, the measurement endpoints should represent the same exposure pathway(s) and mechanisms of toxicity as the assessment endpoints they represent.

3.4.1 Selecting representative assessment endpoint species or communities

It is not practical to evaluate risks to all of the species in vernal pools that may potentially be affected by site-related contaminants. Instead, two specific groups most likely to experience exposure to site-related contaminants in vernal pools were selected.

• Water column organisms

The water column invertebrate community encompasses the zooplankton (mostly crustaceans) which are commonly found in all water bodies. They play an important role in energy and nutrient transfer to higher trophic levels and are also a key food resource for higher trophic levels. The presence of site-derived chemicals in surface water from the vernal pools could result in direct mortality or decreased reproduction in water column invertebrates.

Amphibians are expected to use some of the available vernal pools at the Site for reproduction in the spring. These pools should provide the tadpole stages with a diverse food base. Contaminants, if present in the vernal pools, could result in direct toxicity to the tadpoles themselves or affect the food base used by the growing tadpoles.

• Benthic invertebrates

The sediments in the vernal pools should be able to support a diverse community of benthic species when the pools fill up with water in the spring.

3.4.2 Assessment endpoints

The following assessment endpoints were chosen to help evaluate the potential risks to the receptors identified in section 3.4.1. A risk question follows each assessment endpoint. It was assumed that by evaluating and protecting the assessment endpoints discussed below, all aquatic receptors associated with the vernal pools would be protected as well.

• Maintain a stable and healthy water column community: Are the levels of contaminants in surface water sufficiently high to cause biologically-significant changes or impair the function of the water column invertebrate community or the early life stages of amphibians in vernal pools?

• Maintain a stable and healthy benthic invertebrate community: Are the levels of contaminants in sediments sufficiently high to cause biologically-significant changes or impair the function of the benthic invertebrate community in vernal pools?

8



3.4.3 Measurement endpoints

Measurement endpoints were used to quantify the presence of potential risk to their associated assessment endpoints.

Due to the limited data, only one measurement endpoint was identified for each of the assessment endpoints and their associated risk question.

3.4.3.1 Water column community

Maintain a stable and healthy water column community: Are the levels of contaminants in surface water sufficiently high to cause biologically-significant changes or impair the function of the water column invertebrate community or the early life stages of amphibians in vernal pools?

One line of evidence was used to assess the potential impacts of contaminants present in water from the vernal pools to the local water column invertebrate community and the early amphibian life stages:

< compare the COC concentrations measured in the water samples to conservative no effect surface water benchmarks

3.4.3.2 Benthic macoinvertebrate community

Maintain a stable and healthy benthic invertebrate community: Are the levels of contaminants in sediments sufficiently high to cause biologically-significant changes or impair the function of the benthic invertebrate community in vernal pools?

One line of evidence was used to assess the potential impacts of contaminants present in sediment from the vernal pools to the local benthic invertebrate community:

< compare the COC concentrations measured in the sediment samples to conservative no effect and effect sediment benchmarks

9



4.0 ECOLOGICAL EXPOSURE ASSESSMENT

Vernal pools are temporary, self-contained habitats which are not connected to each other or to permanent bodies of water. Exposure of water column invertebrates, the early life stages of amphibians, and benthic invertebrates was therefore assessed for each vernal pool separately using the available surface water and sediment analytical data.

Water column invertebrates and the early life stages of amphibians were assumed to be exposed mainly via direct contact with the water in the vernal pools. The single surface water sample collected from each vernal pool was also assumed to represent “typical” contaminant levels present in the water column.

Benthic invertebrates were assumed to be exposed to contaminants mainly via direct contact with the sediment layer at the bottom of the vernal pools. The single sediment sample collected from each vernal pool was assumed to represent “typical” contaminant levels present in the sediment.

Therefore, exposure was quantified by using the COC concentrations measured in each surface water and sediment sample collected from the vernal pools .

10



5.0 ECOLOGICAL EFFECTS ASSESSMENT

5.1 Surface water benchmarks

No chronic “effects” water quality benchmarks were available. Therefore, the no effect screening benchmarks used in selecting surface water COCs (see Attachment 1) were retained to support the ecological effects assessment.

5.2 Sediment benchmarks

The screening-level “no effect” sediment benchmarks discussed in section 3.2.2 were expanded to include published “effects” benchmarks. The goal was to enhance the existing no effects sediment benchmark database with chemical-specific values above which an impact on benthic invertebrates would be predicted to occur. Both sets of sediment benchmarks can then be used to better quantify the potential impacts associated with one or more COC exceedences.

Attachment 2 summarizes the available “effect” sediment benchmarks for use in the risk characterization. The consensus-based probable effects concentrations (PECs) by MacDonald et al. (2000) represent contaminant levels above which harmful effects in benthic invertebrates are likely to be observed. The effects range - median (ER-M) by Long et al. (1995) represent contaminant levels above which the incidence of effects are likely to be observed. Finally, the severe effect level (SEL) by Persaud et al. (1993) represent contaminant concentrations at which the sediment is considered heavily polluted and likely to affect the health of sediment-dwelling organisms.

11



6.0 ECOLOGICAL RISK CHARACTERIZATION

6.1 INTRODUCTION

The hazard quotient (HQ) method was used to characterize risk to the selected receptor groups from exposure to the COCs detected in the surface water and sediment samples collected from the two vernal pools at the Site. An HQ for each COC was calculated using the following generic equation:

HQ = exposure concentration ÷ toxicity value

The exposure concentration was represented by the analytical data for the COCs, whereas the toxicity values were represented by the available surface water and sediment benchmarks. In the current assessment, if the HQ was less than 1.0, then it was assumed unlikely that the COC would result in an adverse effect to the target receptor group. Conversely, an HQ above 1.0 indicated the possibility of risk to the target receptor group.

6.2 ASSESSMENT ENDPOINT 1: WATER COLUMN COMMUNITY

Maintain a stable and healthy water column community: Are the levels of contaminants in surface water sufficiently high to cause biologically-significant changes or impair the function of the water column invertebrate community or the early life stages of amphibians in vernal pools?

The potential risk to the water column community associated with the vernal pools was assessed by comparing surface water benchmarks to the surface water analytical data. Attachment 4 compares analytical results and surface water benchmarks for the metals and SVOCs identified as COCs in section 3.2.3.1.

As explained in section 3.1.1, each surface water sample was considered as an individual EU in the risk characterization based on the assumption that aquatic organisms would not move from one vernal pool to another. It should also be noted that finding risk in the surface water from the vernal pools was unavoidable because the same benchmarks used for selecting the surface water COCs were used to calculate HQs for those same COCs.

Several general observations are discussed below (see also Attachment 4):

< In VP-C2, seven metals had HQs above 1.0 (range = 2.9 to 23.9). The three highest exceedences were for mercury (HQ = 23.9), iron (HQ = 21.2), and aluminum (HQ = 9.3), none of which are considered Site-related contaminants.

< In VP-C2, PCP was the only SVOC with a benchmark for calculating a HQ. This HQ equaled 45.3 and suggested a high potential for risk to water column organisms associated with a Site-related contaminant.

< In VP-D1, five metals had HQs above 1.0 (range = 1.8 to 58.7). The highest exceedences were for mercury (HQ = 58.7) and aluminum (HQ = 10.2), neither of which is considered a Site-related contaminant.

< In VP-D1, PCP not was detected in the surface water sample. None of the remaining SVOCs had a benchmark for calculating HQs.

Based on the available evidence, it was concluded that the water column community associated with

12



VP-C2 has a high likelihood of being exposed to unacceptable risk from PCP in the surface water. There is also the potential for unacceptable risk associated with high levels of metals in both vernal pools. However, the metals with the highest HQs (i.e., aluminum, iron, and mercury) are not associated with past activities at the Site and may therefore have been more representative of regional background conditions .

6.3 ASSESSMENT ENDPOINT 2: BENTHIC INVERTEBRATE COMMUNITY

Maintain a stable and healthy benthic invertebrate community: Are the levels of contaminants in sediments sufficiently high to cause biologically-significant changes or impair the function of the benthic invertebrate community in vernal pools?

The potential risk to the benthic community associated with sediment from the vernal pools was assessed by comparing “no effect” and “effect” sediment benchmarks to the sediment analytical data. Attachment 5 compares analytical results and sediment benchmarks for the metals and SVOCs identified as COCs in section 3.2.3.2.

As explained in section 3.1.1, each sediment sample was considered an individual EU in the risk characterization based on the assumption that these organisms would not move from one vernal pool to another.

Several general observations are discussed below (see also Attachment 5):

• For the three metals with sediment benchmarks (i.e., cadmium, copper and lead), the HQs in VP-C2 were below 1.0 for both the “no effect” and “effect” benchmarks. In VP-D1, whereas the “no effect” HQs were slightly above 1.0 for all three analytes (range: 1.1 to 2.9), the “effect” HQs for those same analytes were all below 1.0. These observations lead to the conclusion that the presence of metals in sediment was unlikely to represent an unacceptable risk to benthic invertebrates inhabiting vernal pools at the Site.

• In VP-C2, seven SVOCs had a “no effect” HQ above 1.0. PCP was noteworthy since the HQ for this analyte was 1,920. Only 2-methyl naphthalene and fluorene had “effect” HQs above 1.0 (3.6 and 1.8, respectively). PCP would most likely also have been included in this group if an “effect” benchmark had been available for this analyte.

• In VP-D1, seven SVOCs had a “no effect” HQ above 1.0 (range = 1.2 to 4.4). None of these analytes had “effect” HQs above 1.0

Based on the available evidence, it can be concluded that the benthic invertebrate community associated with VP-C2 would have a high likelihood of being exposed to unacceptable risk from several SVOCs in the sediments. However, PCP would be responsible for most of that potential risk. Also, the total potential risk to benthic invertebrates in VP-C2, even when omitting PCP, was greater than in VP-D1.

6.4 UNCERTAINTY ANALYSIS

6.4.1 Introduction

Uncertainty is an integral component of any SLERA. Numerous assumptions and decisions were made in order to generate the data required for risk characterization. A key component of the process was to identify the main sources of uncertainty for each assessment endpoint and determine how those uncertainties could have affected the outcome of the risk calculations.

13



6.4.2 Uncertainties associated with assessing risk to water column organisms

Some uncertainty may be associated with basing the assessment on a single water sample collected from each vernal pool. However, given the small size of the vernal pools (< 0.1 acre) and their shallow depth (<1.0 ft), it is reasonable to assume that one water sample was in fact representative of the conditions in those pools.

Uncertainty was associated with identifying and using surface water benchmarks. NAWQC were only available for metals. The remaining values represented SCVs or LCVs. All of these values could be considered generic. The majority were probably quite conservative. Because of this built-in conservatism, it is believed to be unlikely that risk associated with measured surface water COCs would have been missed.

Several location-specific physical and chemical variables associated with surface water (e.g., dissolved organic carbon content, hardness, particulate levels) can affect toxicity by binding contaminants or affecting their uptake by aquatic organisms. For metals, using data from unfiltered surface water samples and assuming that the measured concentrations were 100% bioavailable was highly conservative and would have resulted in overly-conservative risk estimates. The only way to eliminate this uncertainty would have been to expose sensitive aquatic organisms directly to surface water collected from vernal pools to determine if dissolved constituents would have affected survival, growth, or reproduction.

Uncertainty was associated with a lack of knowledge about analyte background concentrations in surface water from vernal pools unaffected by the Site. For example, it was not known if the high levels of some metals in surface water were site-specific or represented regional conditions. The latter interpretation was favored because the metals with high potential risk were not associated with past activities at the Site. Without background data, however, the prudent assumption should be made that the observed exceedences were Site related. It is unlikely that the elevated levels of PCP in the water sample collected from VP-C2 reflects background conditions.

Finally, most of the SVOCs did not have published benchmarks and could therefore not be evaluated for risk in this SLERA. The only way to eliminate this uncertainty would have been to expose sensitive aquatic organisms directly to surface water collected from vernal pools.

6.4.3 Uncertainties associated with assessing risk to benthic invertebrates

Some uncertainty may be associated with basing the assessment on a single sediment sample collected from each vernal pool. However, given the small size of the vernal pools (< 0.1 acre), it was reasonable to assume that one sediment sample was in fact representative of the overall conditions of the substrate within the pool.

The sediment benchmarks were assumed to represent generic but conservative values for comparison against the analyte concentrations measured in the two sediment samples. Several location-specific physical and chemical variables (e.g., organic carbon, acid volatile sulfides [AVS] - simultaneously extracted metals [SEM]) may influence whether or not a particular analyte would in fact be toxic. Information concerning these variables was not available. The only way to eliminate this uncertainty would have been to expose sensitive benthic organisms directly to the sediments collected from the vernal pools to determine if these variables would have affected survival and growth.

PCP was present at high concentrations in the sediment sample collected from VP-C2 (690 mg/kg). The only benchmark available to screen this analyte was developed for marine sediments (Washington DOE, 1991). There is uncertainty associated with using a marine benchmark to assess potential risk in a freshwater

14



sediment. However, the extremely high PCP concentration makes it unlikely that risk would disappear if a freshwater benchmark were available.

Finally, numerous COCs did not have established sediment benchmarks and could therefore not be assessed for their risk potential. The only way to eliminate this uncertainty would have been to expose sensitive benthic organisms directly to sediment collected from the vernal pools to determine if survival or growth could be affected.

15



7.0 SUMMARY AND CONCLUSION

A SLERA was performed using a surface water and a sediment sample collected from two separate vernal pools at the HPSS. The goal was to determine if analytes would be present in those two matrices at concentrations indicative of potential risk to benthic invertebrates and water column organisms (specifically, invertebrates and the aquatic life stages of amphibians).

The evidence indicated that the potential for surface water risk was present in both vernal pools based on high levels of metals, and in VP-C2 based on high levels of PCP. It was noted that the metals with the highest HQs (specifically, aluminum, iron, and mercury) were not associated with past activities at the site, and could therefore reflect regional background conditions.

The evidence also indicated that the potential for sediment risk associated with metals was present only in VP-D1 when evaluated based on the “no effect” benchmarks. That potential for risk in VP-D1 became insignificant when it was evaluated using the “effect” benchmarks, suggesting that metals (at least for those with benchmarks) may not be likely risk drivers in the vernal pools.

Numerous SVOCs exceeded their “no effect” benchmarks in both vernal pools. PCP exceeded its “no effect” benchmark by 1,920 in VP-C2 but only by two in VP-D1. Hence, this compound was by far the biggest risk driver in VP-C2. At such high concentrations, it would be reasonable to expect toxicity in the substrate from VP-C2.

Based on the findings of this SLERA, VP-D1 appears to exhibit a marginal risk to ecological receptors that might inhabit it during the spring and early summer. As part of pre-design work, there may be some utility in performing a surface water toxicity test or similar investigation to confirm or deny the presence of risk to receptors in this vernal pool. VP-D1 may have been impacted by historical surface run-off, as there is no indication of a groundwater plume containing PCP in its immediate vicinity. If risk is in fact confirmed, removing contaminated sediments from this pool would be expected to eliminate the risk.

The circumstances concerning VP-C2 appear to be quite different because the very high HQ suggests that risk is more likely to be present at this location. The pool may be situated above a PCP plume originating from the site, and the high water table in this area may provide a direct link between the plume and surface water in VP-C2. This would suggest that removing contaminated sediment from the pool would not be effective unless the plume were also remediated. It might be more effective to create a new vernal pool in a nearby area with a similarly high water table not affected by groundwater contamination. If appropriate and relevant, clean soil could also be used to fill VP-C2 to eliminate exposure to PCP by aquatic receptors at that location in the future.

16



8.0 REFERENCES

Ingersoll, C.G., D.M. MacDonald, N. Wang, J.L. Crane, L.J. Field, P.S. Haverland, N.E. Kemble, R.A. Lindskoog, C. Severn, and D.E. Smorong. 2000. Prediction of sediment toxicity using consensus-based freshwater sediment quality guidelines. EPA 905/R-00/007.

Jones, D.S., G.W. Suter, and R.N. Hull. 1997. Toxicological benchmarks for screening contaminants of potential concern for effects on sediment-associated biota: 1997 revision. Oak Ridge National Laboratory. ES/ER/TM-95/R4.

Long, E.R., D.D. MacDonald, S.L. Smith and F.D. Calder. 1995. Incidence of adverse biological effects with ranges of chemical concentrations in marine and estuarine sediments. Environ. Manag. 19:81-97.

MacDonald, D.D., C.G. Ingersoll and T.A. Berger. 2000. Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Arch. Environ. Contam. Toxicol. 39:20-31.

Metcalf & Eddy. 2002. Vernal pool survey. Amendment to final habitat evaluation survey technical memorandum. Hatheway & Patterson Superfund Site, Mansfield, Massachusetts.

Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of Environment and Energy.

Suter, G.W. and C.L. Tsao. 1996. Toxicological benchmarks for screening potential contaminants of concern for effects on aquatic biota: 1996 revision. Oak Ridge National Laboratory. ES/ER/TM-96/R2.

U.S. EPA. 1995. Final water quality guidance for the Great Lakes system; final rule. 40 CFR 9, 122, 123, 131, and 132 (3/23/95).

U.S. EPA. 1996. Ecotox threshold. EPA 540/F-95/038.

U.S. EPA. 2002. National recommended water quality criteria: 2002. EPA 822-R-02-047.

Washington Department of Ecology. 1991. Washington sediment management standards. Washington Administrative Code, Title 173, DOE, Chapter 173-204.

17

PAST WOOD TREATMENT ACTIVITIES

DRIP PADS

UNDERGROUND STORAGE

TANKS

ABOVEGROUND STORAGE

TANKS

PRIMARY SOURCESPRIMARY SOURCES

SURFACE SPILLS

SUBSURFACE SPILLS

GROUND-WATER

VERNAL POOLS

SOIL COLUMN

RELEASE AND IMPACT AREASRELEASE AND IMPACT AREAS

AMPHIBIANS

INVERTE-BRATES

AFFECTED FAUNAAFFECTED FAUNA

Figure 3: Conceptual Site Model – Vernal Pools Hatheway & Patterson Superfund Site, Mansfield, MA

WATER COLUMN INVERTE-BRATES

BENTHIC INVERTE-BRATES

TADPOLES

Attachment 1: Selection of Surface Water COCs in Two Vernal Pools

Hatheway and Patterson Superfund Site Mansfield, Massachusetts

Screening Level Ecological Risk Assessment

Analyte Surface Water

Benchmark Vernal Pools

VP-C2 COC? Reason Code VP-D1 COC? Reason Code INORGANICS (ug/L) aluminum 8.70E+01 (1) 8.07E+02 YES a 8.90E+02 YES a antimony 3.00E+01 (2) 3.20E-01 NO b 4.70E-01 NO b arsenic 3.10E+00 (2) 5.50E-01 NO b 9.80E-01 NO b barium 4.00E+00 (2) 1.88E+01 YES a 1.96E+01 YES a beryllium 6.60E-01 (2) 3.20E-01 NO b 5.10E-01 NO b cadmium 2.50E-01 (1) 7.20E-01 YES a 2.10E-01 NO b calcium 1.16E+05 (3) 1.25E+04 NO b & c 7.69E+03 NO b & c chromium 1.10E+01 (1) 3.80E+00 NO b ND - -cobalt 2.30E+01 (2) 4.30E+00 NO b 2.10E-01 NO b copper 9.00E+00 (1) 8.30E+00 NO b 4.70E+00 NO b iron 1.00E+03 (1) 2.12E+04 YES a 1.77E+03 YES a lead 2.50E+00 (1) 8.60E+00 YES a 6.60E+00 YES a magnesium 8.20E+04 (3) 2.36E+03 NO b & c 1.27E+03 NO b & c manganese 1.20E+02 (2) 8.82E+02 YES a 1.32E+01 NO b mercury (inorganic) 7.70E-01 (1) 1.84E+01 YES a 4.52E+01 YES a nickel 5.20E+01 (1) 2.80E+00 NO b 4.20E+00 NO b potassium 5.30E+04 (3) 8.40E+02 NO b & c 2.64E+02 NO b & c selenium 5.00E+00 (1) 7.80E-01 NO b 7.40E-01 NO b sodium 6.80E+05 (3) 1.10E+04 NO b & c 5.19E+03 NO b & c vanadium 2.00E+01 (2) 4.00E+00 NO b 6.30E+00 NO b zinc 1.20E+02 (1) 1.87E+01 NO b 2.96E+01 NO b

SEMIVOLATILE ORGANICS (ug/l) benzaldehyde NA - 4.40E-01 YES d 6.00E-01 YES d 4-methylphenol (*) 1.30E+01 (2) 1.20E+00 NO b ND - -2,4-dichlorophenol NA - 8.60E-01 YES d ND - -naphthalene 1.20E+01 (2) 6.00E+00 NO b ND - -3,4-dimethylphenol NA - 7.70E-01 YES d ND - -2,4,6-trichlorophenol NA - 4.20E-01 YES d ND - -2,4,5-trichlorophenol NA - 9.40E+00 YES d ND - -2,3,5,6-tetrachlorophenol NA - 1.20E+01 YES d ND - -pentachlorophenol 1.50E+01 (1) 6.80E+02 YES a ND - -pyrene NA - 2.80E-01 YES d ND - -butyl benzyl phthalate 1.90E+01 (2) ND - - 2.60E-01 NO b bis(2-ethylhexyl)phthalate 3.00E+00 (2) ND - - 7.80E-01 NO b benzo(b)fluoranthene 3.50E+01 (2) 2.50E-01 NO b ND - -

Note 1: only those analytes detected in at least one of the two vernal pool surface water samples are shown in this table Note 2: NA = not available; ND = not detected Note 3: (*) indicates that benchmark shown is for 2-methylphenol

Freshwater benchmark sources were as follows:

The reason codes are as follows: a = the analyte concentration exceeds the benchmark b = the analyte concentration falls below the benchmark c = the analyte is a physiological electrolyte d = no benchmark is available

(1) National Recommended Water Quality Criteria (U.S. EPA. 2002. National Recommended Water Quality Criteria: 2002. EPA-822-R-02-047.) (2) secondary chronic values (Suter, G.W. and C.L. Tsao. 1996. Toxicological benchmarks for screening potential contaminants of concern for effects on aquatic biota: 1996 revision. Oak Ridge National Laboratory. ES/ER/TM-96/R2.) (3) lowest chronic values (Suter, G.W. and C.L. Tsao. 1996. Toxicological benchmarks for screening potential contaminants of concern for effects on aquatic biota: 1996 revision. Oak Ridge National Laboratory. ES/ER/TM-96/R2.)

The order of preference (from most to least preferred) for selecting surface water benchmarks was as follows: NAWQC, secondary chronic values, and lowest chronic value.

Analytical data source: Metcalf & Eddy. 2002. "Vernal pool survey. Amendment to final habitat evaluation survey technical memorandum". Hatheway & Patterson Superfund Site, Mansfield, MA.

Screening Level Ecological Risk Assessment Attachment 2: Selection of Sediment COCs in two Vernal Pools


Analyte

Sediment Benchmark Vernal Pools

"No effect" "Effect" VP-C2 COC? Reason Code VP-D1 COC?

Reason Code

INORGANICS (mg/kg) aluminum NA - NA - 5.15E+03 YES d 4.40E+03 YES d antimony 1.20E+01 (5) NA - 3.60E-01 NO b 2.45E+00 NO b arsenic 9.80E+00 (1) 3.30E+01 (1) 8.80E-01 NO b 1.55E+00 NO b barium NA - NA - 2.80E+01 YES d 8.35E+01 YES d beryllium NA - NA - 1.50E+00 YES d 2.50E+00 YES d cadmium 9.90E-01 (1) 4.98E+00 (1) 9.60E-01 NO b 1.09E+00 YES a calcium NA - NA - 3.03E+03 NO c 3.63E+03 NO c chromium 4.34E+01 (1) 1.11E+02 (1) 2.01E+01 NO b 7.60E+00 NO b cobalt NA - NA - 3.00E+00 YES d 4.90E+00 YES d copper 3.16E+01 (1) 1.49E+02 (1) 1.60E+01 NO b 3.69E+01 YES a iron 2.00E+04 (4) 4.00E+04 (4) 8.78E+03 NO b 1.78E+03 NO b lead 3.58E+01 (1) 1.28E+02 (1) 1.70E+01 NO b 1.04E+02 YES a magnesium NA - NA - 5.25E+02 NO c 3.67E+02 NO c manganese 4.60E+02 (4) 1.10E+03 (4) 2.46E+02 NO b 1.48E+01 NO b mercury (inorganic) 1.80E-01 (1) 1.06E+00 (1) 7.00E-02 NO b 1.00E-02 NO b nickel 2.27E+01 (1) 4.86E+01 (1) 6.60E+00 NO b 1.38E+01 NO b potassium NA - NA - 8.98E+01 NO c 1.97E+02 NO c selenium NA - NA - 3.40E+00 YES d 3.40E+00 YES d silver 1.00E+00 (2) 3.07E+02 (2) 7.00E-02 NO b ND - -sodium NA - NA - 8.20E+01 NO c 1.37E+02 NO c vanadium NA - NA - 9.60E+00 YES d 3.12E+01 YES d zinc 1.21E+02 (1) 4.59E+02 (1) 2.28E+01 NO b 4.68E+01 NO b

SEMIVOLATILE ORGANICS (ug/kg) benzaldehyde NA - NA - ND - - 1.30E+03 YES d naphthalene 1.76E+02 (1) 5.61E+02 (1) 5.20E+02 YES a ND - -2-methylnaphthalene 7.00E+01 (2) 5.61E+02 (1)* 2.00E+03 YES a ND - -2,4,6-trichlorophenol NA - NA - 5.00E+02 YES d ND - -2,4,5-trichlorophenol NA - NA - 4.00E+03 YES d ND - -1,1'-biphenyl 1.10E+03 (3) NA - 6.20E+02 NO b ND - -acenaphthene 1.60E+01 (2) 5.36E+02 (1)** 2.60E+02 YES a ND - -dibenzofuran 2.00E+03 (3) NA - 4.40E+02 NO b ND - -fluorene 7.74E+01 (1) 5.36E+02 (1) 9.60E+02 YES a ND - -2,3,5,6-tetrachlorophenol NA - NA - 9.90E+03 YES d ND - -pentachlorophenol 3.60E+02 (6) NA - 6.90E+05 YES a 7.85E+02 YES a phenanthrene 2.04E+02 (1) 1.17E+03 (1) 5.70E+02 YES a 4.40E+02 YES a fluoranthene 4.23E+02 (1) 2.23E+03 (1) ND - - 5.15E+02 YES a pyrene 1.95E+02 (1) 1.52E+03 (1) 2.50E+02 YES a 8.65E+02 YES a butylbenzyl phthalate 1.10E+04 (3) NA - 4.60E+02 NO b ND - -benzo(a)anthracene 1.08E+02 (1) 1.05E+03 (1) ND - - 3.95E+02 YES a chrysene 1.66E+02 (1) 1.29E+03 (1) ND - - 3.40E+02 YES a di-n-octyl phthalate >100,000 (5) NA - 3.70E+02 NO b ND - -benzo(b)fluoranthene NA - 5.36E+02 (1)** ND - - 5.25E+02 YES d benzo(k)fluoranthene 2.40E+02 (4) 5.36E+02 (1)** ND - - 3.45E+02 YES a

Note 1: only those analytes detected in at least one of the two vernal pool sediment samples are shown in this table Note 2: NA = not available; ND = not detected Note 3: the units are in dry weight note 4: * = benchmark shown is for naphthalene; ** = benchmark shown is for fluorene

Sediment benchmark sources were as follows:

The reason codes are as follows: a = the analyte concentration exceeds the benchmark b = the analyte concentration falls below the benchmark c = the analyte is a physiological electrolyte d = no benchmark is available

(3) U.S. EPA. 1996. ECO Update: Ecotox Thresholds. EPA 540/F-95/038. January, 1996

(6) Washington Sediment Management Standards. 1991. Washington Administrative Code, Title 173. Dept. of Ecology, Chapter 173-204.

(4) Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of Environment and Energy. (5) Jones, D.S., G.W. Suter and R.N. Hull. 1997. Toxicological benchmarks for screening contaminants of potential concern for effects on sediment-associated biota: 1997 revision. Oak Ridge National Laboratory. ES/ER/TM-95/R4

Analytical data source: Metcalf & Eddy. 2002. "Vernal pool survey. Amendment to final habitat evaluation survey technical memorandum". Hatheway & Patterson Superfund Site, Mansfield, MA.

(1) MacDonald, D.D., C.G. Ingersoll, and T.A. Berger. 2000. Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Arch. Environ. Contam. Toxicol. 39:20-31. (2) Long, E.R., D.D. MacDonald, S.L. Smith and F.D. Calder. 1995. Incidence of adverse biological effects with ranges of chemical concentrations in marine and estuarine sediments. Environ. Manag. 19:81-97

Attachment 3: Summary of COCs in Surface Water and Sediment from Two Vernal Pools



Analytes

Vernal Pools Reason for COC Selection Surface Water Sediments Surface Water Sediments

VP-C2 VP-D1 VP-C2 VP-D1 Exceeds

Benchmarks No

Benchmarks Exceeds

Benchmarks No

Benchmarks INORGANICS aluminum Y Y Y Y • • barium Y Y Y Y • • beryllium N N Y Y • cadmium Y N N Y • •* cobalt N N Y Y • copper N N N Y •* iron Y Y N N • lead Y Y N Y • •* manganese Y N N N • mercury Y Y N N • selenium N N Y Y • vanadium N N Y Y • Total No. of COCs 7 5 6 9

SEMIVOLATILE ORGANICS benzaldehyde Y Y N Y • • naphthalene N N Y N •* 2-methylnaphthalene N N Y N •** 2,4-dichlorophenol Y N N N • 3,4-dimethylphenol Y N N N • 2,4,6-trichlorophenol Y N Y N • • 2,4,5-trichlorophenol Y N Y N • • acenaphthene N N Y N •* fluorene N N Y N •** 2,3,5,6-tetrachlorophenol Y N Y N • • pentachlorophenol Y N Y Y • •** phenanthrene N N Y Y •* fluoranthene N N N Y •* pyrene Y N Y Y • •* benzo(a)anthracene N N N Y •* chrysene N N N Y •* benzo(b)fluoranthene N N N Y •* benzo(k)fluoranthene N N N Y •* Total No. of COCs 8 1 10 8 Source: Attachments 1 and 2 of the Vernal Pool SLERA

* = the measured concentration fell between the "no effect" and "effect" sediment benchmarks for this analyte ** = the measured concentration exceeded the "effect" sediment benchmark for this analyte

Attachment 4: Potential Risks Associated with Surface Water in Two Vernal Pools



Analyte

EFFECT EXPOSURE RISK (HQ)

Surface Water Benchmark

Vernal Pools Vernal Pools

VP-C2 VP-D1 VP-C2 VP-D1 INORGANICS (ug/L) aluminum 8.70E+01 8.07E+02 8.90E+02 9.28E+00 1.02E+01 barium 4.00E+00 1.88E+01 1.96E+01 4.70E+00 4.90E+00 cadmium 2.50E-01 7.20E-01 2.10E-01 2.88E+00 8.40E-01 iron 1.00E+03 2.12E+04 1.77E+03 2.12E+01 1.77E+00 lead 2.50E+00 8.60E+00 6.60E+00 3.44E+00 2.64E+00 manganese 1.20E+02 8.82E+02 1.32E+01 7.35E+00 1.10E-01 mercury (inorganic) 7.70E-01 1.84E+01 4.52E+01 2.39E+01 5.87E+01

SEMIVOLATILE ORGANICS (ug/l) benzaldehyde NA 4.40E-01 6.00E-01 - -2,4-dichlorophenol NA 8.60E-01 ND - -3,4-dimethylphenol NA 7.70E-01 ND - -2,4,6-trichlorophenol NA 4.20E-01 ND - -2,4,5-trichlorophenol NA 9.40E+00 ND - -2,3,5,6-tetrachlorophenol NA 1.20E+01 ND - -pentachlorophenol 1.50E+01 6.80E+02 ND 4.53E+01 -pyrene NA 2.80E-01 ND - -Source: Attachment 1 of the Vernal Pool SLERA

notes: ND = not detected; NA = not available bolded value indicates HQ > 1.0 - = HQ cannot be calculated because analyte was ND and/or benchmark was NA

Attachment 5: Potential Risks Associated with Sediment in Two Vernal Pools



Analyte

EFFECT EXPOSURE RISK (HQ) Sediment Benchmark VP-C2 VP-D1 VP-C2 VP-D1

"No effect" "Effect" "No Effect" "Effect" "No Effect" "Effect" INORGANICS (mg/kg) aluminum NA NA 5.15E+03 4.40E+03 - - - -barium NA NA 2.80E+01 8.35E+01 - - - -beryllium NA NA 1.50E+00 2.50E+00 - - - -cadmium 9.90E-01 4.98E+00 9.60E-01 1.09E+00 9.70E-01 1.93E-01 1.10E+00 2.19E-01 cobalt NA NA 3.00E+00 4.90E+00 - - - -copper 3.16E+01 1.49E+02 1.60E+01 3.69E+01 5.06E-01 1.07E-01 1.17E+00 2.48E-01 lead 3.58E+01 1.28E+02 1.70E+01 1.04E+02 4.75E-01 1.33E-01 2.90E+00 8.12E-01 selenium NA NA 3.40E+00 3.40E+00 - - - -vanadium NA NA 9.60E+00 3.12E+01 - - - -

SEMIVOLATILE ORGANICS (ug/kg) benzaldehyde NA NA ND 1.30E+03 - - - -naphthalene 1.76E+02 5.61E+02 5.20E+02 ND 2.95E+00 9.27E-01 - -2-methylnaphthalene 7.00E+01 5.61E+02 2.00E+03 ND 2.86E+01 3.57E+00 - -2,4,6-trichlorophenol NA NA 5.00E+02 ND - - - -2,4,5-trichlorophenol NA NA 4.00E+03 ND - - - -acenaphthene 1.60E+01 5.36E+02 2.60E+02 ND 1.63E+01 4.85E-01 - -fluorene 7.74E+01 5.36E+02 9.60E+02 ND 1.24E+01 1.79E+00 - -2,3,5,6-tetrachlorophenol NA NA 9.90E+03 ND - - - -pentachlorophenol 3.60E+02 NA 6.90E+05 7.85E+02 1.92E+03 - 2.18E+00 -phenanthrene 2.04E+02 1.17E+03 5.70E+02 4.40E+02 2.79E+00 4.87E-01 2.16E+00 3.76E-01 fluoranthene 4.23E+02 2.23E+03 ND 5.15E+02 - - 1.22E+00 2.31E-01 pyrene 1.95E+02 1.52E+03 2.50E+02 8.65E+02 1.28E+00 1.64E-01 4.44E+00 5.69E-01 benzo(a)anthracene 1.08E+02 1.05E+03 ND 3.95E+02 - - 3.66E+00 3.76E-01 chrysene 1.66E+02 1.29E+03 ND 3.40E+02 - - 2.05E+00 2.64E-01 benzo(b)fluoranthene NA 5.36E+02 ND 5.25E+02 - - - 9.79E-01 benzo(k)fluoranthene 2.40E+02 5.36E+02 ND 3.45E+02 - - 1.44E+00 6.44E-01 Source: Attachment 2 of the Vernal Pool SLERA

Notes: NA = not available; ND = not detected, HQ = hazard quotient bolded value indicates HQ > 1.0 - = HQ cannot be calculated because analyte was ND and/or benchmark was NA

Documents

Screening-Level Ecological Risk AssessmentA SLERA performed in 2003 using surface water and sediment analytical data collected from the Rumford River indicated the presence of potential