UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION I

ONE CONGRESS STREET SUITE 1100 BOSTON, MASSACHUSETTS 02114-2023

MEMORANDUM i

Date: March 26, 2001

Subj: Review of report Preliminary Ecological Risk Evaluation for the Mohawk Tannery Superfund Site, Nashua, NH and general recommendations for sampling and analysis to support ecological risk assessment activities associated with the Engineering Evaluation/Cost Analysis (EE/CA) and Remedial Investigation/Feasibility Study (RI/FS)

From: Richard Sugatt, Environmental Scientist Technical Support Section, OSRR

To: Neil Handler, RPM, New Hampshire and Rhode Island Superfund Section. OSRR

Thank you for the opportunity to review the above-referenced document (attached) and to provide sampling and analysis recommendations to support the screening level ecological risk assessment (SLERA) that will be conducted as part of the Engineering Evaluation/Cost Analysis (EE/CA). I have also provided some sampling and analysis recommendations to support the SLERA and baseline ecological risk assessment for the RI/FS. which will evaluate ecological risks to organisms exposed to sediments and surface water of the Nashua River.

The above-referenced document was prepared for EPA by Lockheed Martin Systems Support and Training Services Company. The conclusions of the report are based on the very limited data that was already available for the site. Site-specific contaminant concentrations were screened against relevant ecotoxicological benchmarks for surface water, soil and sediment. I agree with the conclusion of the report that this screening strongly suggests that aquatic and terrestrial organisms associated with this area are being exposed to levels of contamination that could result in adverse biological effects.

The focus of the Engineering Evaluation/Cost Analysis (EE/CA) is on the on-site disposal areas. As a result, it is recommended that the SLERA for the EE/CA evaluates risks to terrestrial and semi-aquatic organisms potentially exposed to soils, as well as the surface water and sediments in the waste lagoons. In addition, the SLERA for the EE/CA should evaluate the risks to aquatic

organisms potentially exposed to surface water and sediments in the waste lagoons. The SLERA for the EE/CA should also evaluate qualitatively the potential risks to aquatic organisms in the Nashua River in the event of catastrophic release of lagoon wastes to the Nashua River through lagoon failure or flooding.

At this time there is not a well-defined set of chemicals of potential concern (COPCs) for this site. The analyte list for all on-site soil, surface water and sediment locations should include the EPA target analyte list (TAL), the target compound list (TCL), and chlorinated dibenzodioxins/furans. Representative sediment samples from the lagoons should be analyzed for total organic carbon (TOC), acid volatile sulfides (AVS) and simultaneous extracted metals (SEM). Surface water samples from the lagoons should be taken on a filtered and unfiltered basis.

To better identify those aquatic and terrestrial receptors associated with the tannery facility and its surroundings, a field visit should be performed to collect additional information and a more detailed description of the habitat and organisms associated with the site. In addition, a Quality Assurance Project Plan (QAPP) should be developed to collect an expanded set of surface soil, sediment, surface water and groundwater samples for the full suite of chemical analyses. This QAPP should identify data quality objectives for field sampling and laboratory analysis of surface soil on the site, and surface water and sediment in the lagoons to support the SLERA to identify a list of COPCs to be incorporated into the baseline ecological risk assessment that will be conducted during the RI/FS.

In development of the QAPP for additional sampling and analysis at the site, the following considerations should be taken in to account, in order to provide data suitable for ecological risk assessment purposes:

1. Sediment samples should be collected for analysis for TAL and TCL analytes, acid volatile sulfides/simultaneous extracted metals (AVS/SEM), grain size, and total organic carbon. Sample depths of 1-6" are suitable for all sediment parameters except AVS/SEM, which should be taken as a discreet sample in the 1-10 cm depth.

2. Prior to preparation of the QAPP, a few sediment samples should be obtained from the lagoons to assess the percent solids of representative sediments, in order to avoid later problems with data rejection. EPA Region I requires that positive sample results are to be designated as estimated (J) when % solids are 10% or greater and less than or equal to 30%. All positive results are to be rejected (R) when % solids is less than 10%. All non-detected results are to be rejected when % solids is less than or equal to 30%. If sediments have too much moisture, freeze-drying should be considered to increase the % solids of those samples that will be analyzed for parameters other than VOCs.

3. Volatile organic compounds in sediment should use EPA SW846 Method 5035.

4. Data quality objectives should be established to detection limits suitable to the use of ecological benchmarks for each medium.

5. Surface water should be analyzed for dissolved oxygen, pH, specific conductance, and temperature (on-site), and TAL and TCL parameters for both filtered and unfiltered samples.

6. A follow-up sampling round may be required to fill any remaining data gaps and to account for seasonal variability in parameters such as AVS/SEM.

7. Soil samples should be taken at the 0-1' depth.

Surface soils should be analyzed in areas where suitable terrestrial habitat coincides with areas of known or suspected contamination.

More detailed recommendations will be provided during the upcoming EPA review of the work plan for the EE/CA.

These general recommendations also apply to sampling and analysis of surface water and sediment in the Nashua River for the RI/FS. For the RI/FS, sediment samples should be taken upstream of the site, at the site, and downstream of the site in the Nashua River. Surface water samples should be taken in the Nashua River upstream, adjacent and downstream of the site, in any nearby wetland areas potentially affected by the site, and in the hyporheic zone (surface water/groundwater interface) in any areas where groundwater from the site may be emerging in the Nashua River. More detailed recommendations will be provided during the upcoming EPA review of the work plan for the RI/FS.

Preliminary Ecological Risk Evaluation for the

Mohawk Tannery

Nashua, New Hampshire

1.0 INTRODUCTION

This Preliminary Ecological Risk Evaluation (PRE) for the Mohawk Tannery focuses on data compiled in the Final Site Inspection Priontization Report for Mohawk Tannery Nashua, New Hampshire (NHDES), dated November, 1996 (SIP report), EPA Analytical Results from Recent Sampling Activities at the Mohawk Tannery Site in Nashua, New Hampshire (EPA), dated December 13, 2000, and Preliminary Sludge Characterization Report - Areas I and II - Mohawk Tannery Site Nashua, New Hampshire (ERI), dated January 11, 2001 This screening of preliminary data has been prepared according to procedures recommended in the EPA document, Ecological Risk Assessment Guidance for Superfund, Process for Designing and Conducting Ecological Risk Assessments, Draft Final (EPA 540/R-97-006) (EPA, 1997) The purpose of this review is to evaluate current data on the site with respect to accepted ecological benchmarks, to identify chemicals that might pose a potential risk to aquatic or terrestrial organisms Background information on the site is only briefly summarized in order to provide a context for subsequent steps.

This screening of preliminary data consists of a Screening-Level Problem Formulation and Ecological Effects Evaluation, and contains the following sections

* Site History

* Previous Investigations

* Environmental Setting

* Nature and Extent of Contamination

* Exposure Pathway Analysis

* Screening-Level Methodology

* Results of the Screening-Level Evaluation

* Discussion

4 References

This screening of preliminary data is based on the use of limited site-specific information on the presence of ecological receptors and other natural features, therefore some of the sections listed above contain only a brief summary of the information.

2.0 SITE HISTORY

Mohawk Tannery, also known as Granite State Leathers (GSL), operated from 1924 to 1984. During the operation of the tannery, alkaline and acidic waste streams were produced The alkaline waste stream was the result of the pre-tanning preparation process; the acid waste stream was the result of the tanning process itself 50,000 gallons of alkaline waste produced per day (GPD) was composed primarily of undissolved lime and protemaceous solids such as, hair, fleshings and hide scraps 100,000 GPD of acid waste consisted mostly of spent chromium tanning materials and some hide residue "pickling" wastes

Little is known regarding tannery effluent treatment practices from 1924 to the 1960's due to incomplete records It has been assumed that, prior to the establishment of two lagoons (Areas I and II) in the 1960's, waste products were discharged directly to the Nashua River Once the lagoons were established, the alkaline and acid waste stream effluents were combined and the liquid fraction overflow from the lagoons was discharged to the Nashua River During the 1970's, from approximately 1971 to 1973/1974, a separate treatment process for the waste streams was established The alkaline effluent was pumped from the mam facility underground to an elevated wooden sluiceway through which it was transported to a screen building for removal of solids After the removal of solids, the effluent was transported through a second wooden sluiceway to the settling lagoons, first to Area II, then to Area I for long-term deposition

3.0 PREVIOUS INVESTIGATIONS

Several studies and sampling investigations have been conducted by the New Hampshire Department of Environmental Services (NHDES), the United States Environmental Protection Agency (EPA) and several environmental consulting firms from 1985 to 2001 The most comprehensive environmental investigation was the Phase II Hydrogeologic Study, Granite State Leathers, Inc, Nashua, New Hampshire, conducted in 1985 by Goldberg-Zomo and Associates, Inc (GZA).

One source available to review and provide analytical data for the screening of preliminary data and ecological effects evaluation was The New Hampshire Department of Environmental Services Final Site Inspection Prioritization Report (SIP) from 1996. This document summarizes the data from the various previous reports, however only a small fraction of the previously-collected data is presented in the SIP report. Also, the source and nature of the data presented in the SIP report is not always clear. In one instance the same analytical results appear to have been reported as both surface water listed in a table, and sediment data depicted on a map. A more detailed screening of surface water and sediment data would require use of some of the original reports.

Additional information was available from the 2000 EPA report, EPA Analytical Results from Recent Sampling Activities at the Mohawk Tannery Site in Nashua, New Hampshire, and the 2001 ERI report, Preliminary Sludge Characterization Report - Areas I and II - Mohawk Tannery Site, Nashua, New Hampshire The two reports, respectively focused on providing preliminary sludge characterization data from Area I and Area II lagoons to help determine the ability of a portable XRF to measure chromium concentrations in the sludge and to identify disposal alternatives for the sludge.

4.0 ENVIRONMENTAL SETTING

The Mohawk Tannery property is located in the lower Merrimack River basin on the eastern bank of the Nashua River (Figure 1), in a residential area one mile west of the City of Nashua. The site is composed of two abutting properties, a 15-acre developed parcel to the north containing the tannery facility, and another 15-acre undeveloped parcel to the south. The SIP report provides little information

on the ecological setting. From an aerial photograph taken in the 1970's, it can be seen that the site is bordered to the north by mixed hardwood and coniferous forest, to the south by predominantly mixed-hardwood forest, to the west by the Nashua River, and to the east by a residential area.

Nine potential Source Areas were identified in the SIP Area I and II are located 20 to 30 feet east of the Nashua River while Areas III, IV, V and VI are located 260, 200, 370 and 400 feet east of the Nashua River, respectively (Figure 2) All six areas are within the 100-year flood zone Area VII is the most southern source of contamination, while Area VIII, the Fimbel Door Landfill, is located to the north of the tannery facility Area IX consists of the NPDES discharge pipe and the Lagoon drainage line both at the edge of the Nashua River bank Most of these areas are assumed to be areas where waste sludges from the tannery were deposited It should be noted that although waste sludges were placed in the Fimbel Door Landfill (Area VIII) this area is not currently considered part of the site It is also reported that the landfill is capped, lined, and has a leachate collection system installed (August 9, 1990, Scope of Work for Remedial Closure Study Fimbel Landfill)

5.0 NATURE AND EXTENT OF CONTAMINATION

Sampling at the tannery facilities has been largely focused on surface and sub-surface soil in the various disposal areas on the site Very limited sampling has been performed in the Nashua River or in non-source areas on site Data summaries presented in the available reports are only sufficient to provide a preliminary screening of risk, and a baseline for a more in-depth investigation The available data for each medium of ecological interest (surface soil, surface water, and sediment) are described below

Most of the soil data in the SIP report are from samples collected by GZA in 1985, from depths between 2.5 and 12 feet below ground surface These samples are not immediately relevant to ecological risk analysis, because direct contact with any terrestrial receptors is unlikely to occur at depths greater than one foot. Among the data presented is a single surface soil sample collected by the NH DES at the dram pipe located 10 feet back from the water's edge on the eastern bank of the Nashua River. Chemicals detected include elevated levels of chromium, cadmium, and lead In addition, more recent soil data were found in the 2000 EPA report, EPA Analytical Results from Recent Sampling Activities at the Mohawk Tannery Site in Nashua, New Hampshire and the 2001 ERI report, Preliminary Sludge Characterization Report - Areas I and II - Mohawk Tannery Site, Nashua, New Hampshire. All the data contained in these two reports are from samples taken from within the two lagoons (Areas I and II) at the site.

The primary source of sediment data appears to be from samples collected in the Nashua River by NHDES on October 8,1993. These data are presented in a series of hand-drawn maps of the Nashua River near the Mohawk Tannery outfall pipe. The maps show the sample locations, with concentrations of cadmium, chromium, and lead at each location. Some of this data appears to have been inadvertently presented as surface water data in Table 4 of the SIP report, however the text and Table 3 of the SIP report support interpreting these data as sediment data. Samples from the Nashua River detected elevated levels of chromium, cadmium and lead. The available sediment data present the results of analytes for metals only. No sediment data for organic chemicals was available for this evaluation.

As mentioned above, some of the data presented as surface water data in Table 4 of the SIP report may in fact be sediment data, however the samples labeled "NPDES Effluent Data" were assumed to be surface water data for purposes of this review. Additional surface water data may be available in the source documents, however most of this data is over ten years old, and would probably have little bearing on current water quality conditions within the Nashua River.

In addition to the samples discussed above, previous investigations conducted by various environmental consultants have detected elevated levels of metals and VOC's in sludges, soils and groundwater There is reason to suspect that surface soil and seep contamination may exist, however additional sampling should be conducted targeting surficial areas accessible to ecological receptors

Other possible source areas were mentioned in the SIP report Several 55 gallon drums may have provided another source of contamination These drums were originally from the Amoskeag Leather Co and were transported to the Mohawk facility and disposed of in the Fimbel Door Landfill Other sources of potential contamination include two discharges of sodium hydro sulfate" discussed in the SIP report These discharges are described as consisting of separate discharges of approximately 100 gallons and 1282 gallons These discharges were accidentally released in the vicinity of the storage tank located to the east of the mam facility

6.0 EXPOSURE PATHWAY ANALYSIS

The Mohawk Tannery property is located within the Merrimack River basin, and adjacent to the Nashua River The SIP report provides a general inventory of the amount of wetland frontage within 15 miles along the Nashua River and the Merrimack River (0 66 linear miles)

All sensitive environments outlined in the SIP Report were identified by the New Hampshire Natural Heritage Program and the Massachusetts Natural Heritage Program endangered species information was also provided The report identifies Area I and Area II (depositional lagoons) as wetlands located in the site The report also identifies the following threatened or endangered species as present in the vicinity of the tannery property (0 25 miles to 3-4 miles) banded sunfish, birds foot violet, burgrass, eastern hognose snake, northern prickly ash, goats rue, bald eagle, Siberian chives, American plum, swamp azalea, hairy stargrass and geometric moth Although, the actual location of these species was not provided, northern prickly ash, a tree listed as a New Hampshire endangered species reportedly exists within 1 to 2 miles radius of the site

The Nashua River provides habitat to a number of warmwater species such as yellow perch, sunfish and largemouth bass The Nashua River is also stocked with anadromous species, approximately 200 shad and 600 alewife are stocked annually In addition, tributaries of the Nashua River are stocked with trout

The site is located one mile west of the City of Nashua in a residential area, hence, it is possible that terrestrial habitat available for wildlife species beyond the immediate area of the site is limited

7.0 SCREENING-LEVEL METHODOLOGY

This section presents a comparison of surface water, sediment, and soil site-specific contaminant concentration data with ecotoxicological benchmarks appropriate to those media This screening process identifies the Contaminants of Potential Concern (COPCs) for each medium Chemicals selected as COPCs warrant further investigation It is likely that additional sampling and analysis of surface water, soils, and sediments will be necessary to derive a more complete list of COPCs This preliminary screening is only based on one surface water sample, and only a few sediment samples Most of these samples appear to have been analyzed for metals, in the case of surface water, volatile organic compounds (VOCs), and in the case of surface soils and test pits, dioxms and furans

Table 1 presents the surface water analytical results from the NPDES outfall, which is shown in Figure 2 These data were compared with freshwater Federal Ambient Water Quality Criteria (AWQC) Table 1 also includes the selection of potential inorganic COPCs for surface water The benchmarks selected

for surface water are the acute (Criterion Maximum Concentration or CMC) and chronic (Criterion Continuous Concentration or CCC) AWQC for freshwater These values are cited in the National Recommended Water Quality Criteria - Correction (EPA, 1999)

The AWQC are Applicable or Relevant and Appropriate Requirements (ARARS) for surface waters and were used when available The AWQC are derived from at least eight LC50s (concentration lethal to 50% of organisms tested) and three chronic values (CVs), encompassinga variety of aquatic species They are designed to be protective of 95% of aquatic life The criterion continuous concentration (CCC) and criterion maximum concentration (CMC) were used in this evaluation The CCC is an estimate of the highest concentration of a material in surface water to which an aquatic community can be exposed indefinitely without resulting in an unacceptable effect (EPA, 1999) The CMC is an estimate of the highest concentration of a material in surface water to which an aquatic community can be exposed briefly without resulting in an unacceptable effect (EPA, 1999) For certain metals, the AWQC can be adjusted to account for site-specific hardness, however in this case the hardness of the receiving water was not known and a default value of 100 mg/L as CaCO3 was used

For some chemicals, AWQC values are not available. Other screening benchmarks for these chemicals were found in Suter and Tsao (1996) This document representsa compilation of screening benchmarks for surface waters developed for the Oak Ridge Reservation by the Environmental Sciences Division of the Oak Ridge National Laboratory. The Tier II secondary acute and secondary chronic values were developed according to procedures described in the EPA document Proposed Water Quality Guidance for the Great Lakes System. These values are derived in a manor similar to that used to develop AWQC, except that fewer data are required to develop Tier II values In addition, a water quality criterion developed by the U.S. EPA Great Lakes Initiative and cited in Suter and Tsao (1996) was used for phenol.

Sediment evaluation used the sediment guidelines prepared by the Ontario Ministry of the Environment (OMOE) to help environmental managers assess sediment quality (Jaagumagi et al. 1995). The major objective of the sediment quality guidelines is to provide protection of biological resources against the lethal and sub-lethal effects of contaminated sediments. These biological resources include organisms that could be affected directly; that is, the benthic species that live in or feed on the sediment and water column organisms that could sorb contaminants released from the sediment to water and/or through the consumption of benthic organisms; and those affected indirectly, such as non-aquatic consumers (humans and wildlife) or top aquatic predators such as fish.

The biologically based guidelines have been derived to protect those organisms that are directly affected by contaminated sediment and to protect against biomagnification of contaminants through the food chain. The lowest effect level (LEL) indicates a level of sediment contamination that can be tolerated by the majority of benthic organisms. A severe effect level (SEL) indicates a level at which pronounced disturbance of the sediment-dwelling community can be expected. The SEL is a sediment concentration of a compound that would be detrimental to the majority of benthic species.

The maximum sediment analytical results from the data presented in the SIP report were compared to the Lowest Effect Levels (LELs) and the Severe Effect Levels from the Ontario Ministry of the Environment (OMOE) sediment quality guidelines (Jaagumagi et al. 1995). This comparison is found in Table 2. Concentrations exceeding low and high benchmarks are highlighted in the screening tables.

An assessment of inorganic and organic soil contaminant concentrations was based on samples collected in 2000 (EPA and ERI) and 1995 (GZA), respectively. The maximum detected value for each chemical was selected for comparison with ecological screening values as an initial step in determining potential risk. The soil results for inorganic chemicals represent the maximum values from samples

taken primarily in the two lagoons The results for organic chemicals represent maximum values from samples taken at various depths in a number of different disposal areas within the site This evaluation of soil contaminant levels (Table 3) was conducted using the lowest of benchmarks designed to be protective of soil invertebrates, terrestrial plants, and wildlife These benchmarks were developed as preliminary remediation goals (PRGs) by Efroymson et al (1997) for the Oak Ridge National Laboratory in Oak Ridge, Tennessee The PRGs are a compilation of benchmarks developed separately for the various plant and animal groups The soil invertebrate and terrestrial plant benchmarks were developed primarily based on literature on direct toxicity of various chemicals to these groups The wildlife benchmarks were developed for a number of mammal and bird species common in the Eastern United States and are based on conservative food chain modeling All of these benchmarks carry a fairly high degree of uncertainty however they are frequently used as a conservative screening tool for soil data The values presented in Table 3 represent the lowest benchmark for each chemical among the various benchmarks developed for soil invertebrates plants and terrestrial wildlife

Table 4 presents an evaluation of surface soil and test pit data from recent sampling (ERI) of the lagoons (Areas I and II) for dioxms and furans The samples were analyzed for 17 individual dioxm and furan congeners Toxicological benchmarks are generally available only for the compound 2,3,7,8­tetrachlodibenzo-p-dioxm (2,3,7,8-TCDD), therefore the soil data were modified using the Toxicity Equivalency Factor (TEF) approach to convert data for the various congeners to a toxicologically equivalent value for 2,3,7,8-TCDD In this approach, the concentration of each congener is multiplied by a TEF representing an estimate of the toxicity of each congener relative to that of 2,3,7,8-TCDD (which has a TEF of 1) The resulting products are summed to achieve a single 2,3,7,8-TCDD equivalent for comparison with benchmarks There are slightly different sets of TEFs to adjust for risk to various wildlife groups, fish, mammals/humans, and birds

The adjusted soil data are compared with low risk and high risk sediment benchmarks developed to evaluate 2,3,7,8-TCDD risk to fish and mammals specified in Interim Report on Data and Methods for Assessment of 2,3,7,8-Tetrachlorodibenzo-p-dioxm Risks to Aquatic Life and Associated Wildlife (EPA, 1993) The reason for using a sediment benchmark value to evaluate soil data is the proximity of the two lagoons to the Nashua River It is plausible that flooding, breaching of the lagoon berms, heavy rams, or some combination of these events could cause soil contaminants to migrate to the Nashua River It is also possible that the lagoons themselves could be flooded for periods of time, in which case the soils of the lagoon may function as sediment from an ecological standpoint

8.0 RESULTS OF THE SCREENING-LEVEL EVALUATION

The surface water sample collected from the NPDES effluent indicated the presence of the organic compounds methylene chloride and phenol, as well as arsenic, silver and zinc The concentration of phenol exceeded the Great Lakes acute value for this chemical The concentration of silver exceeded the acute AWQC by more than one order-of-magnitude The concentration of zinc exceeded the acute and chronic criteria for this metal These findings suggest that there is potential risk to aquatic organisms in the Nashua River from organic and inorganic chemicals, based on the very limited data available for evaluation

Sediment analysis indicated values of cadmium, chromium and lead orders-of-magnitude above the LEL and SEL values for these metals If these concentrations are indicative of current conditions, there is potential risk of adverse effects on benthic (sediment-dwelling) organisms, and possibly to organisms that may consume benthic organisms It should be noted that this evaluation was limited to data on a small number of metals, other inorganic and organic chemicals might be present as well

Soil analysis was based on surface soil and test pit samples collected in areas of tannery sludge deposition It must be noted that any ecological screening of soil data carries a high degree of uncertainty, because there is no universally-accepted set of screening benchmarks for soil An additional source of uncertainty is the extent to which the soil data available represents surface soil conditions Most ecological risk assessments use soil samples taken from 0 to 1 foot depth as this is the biologically active zone in soil The results presented in this evaluation range in depth from surface samples to samples at several feet in depth

Based on the information available the organic compounds 2 4 6-tnchlorophenol pentachlorophenol and phenol are present at concentrations that may pose a risk to terrestrial wildlife The inorganic chemicals arsenic copper chromium lead and zinc are all present at concentrations that exceed benchmarks for terrestrial plants or wildlife The uncertainty in this analysis would be reduced with additional surficial soil sampling and analysis in source areas and non-source areas of the site to provide some basis for determining average exposures

The evaluation of dioxms and furans was conducted by comparing data from soil from the two lagoons to sediment benchmarks developed through modeling to represent levels of low and high risk to fish, birds, and mammals The use of sediment benchmarks to evaluate soil is based on the premise that soil in the lagoons might become sediment during periods of flooding, or may be washed into the river sediments during periods of high water This evaluation indicates that several of the surface soil samples, and all of the test pit samples, exceed their low-risk benchmarks The test pit samples exceed the high-risk benchmarks for all groups by one to two orders of magnitude This suggests that if a sediment exposure were to apply to these chemicals due to flooding, erosion, or other factors there could be substantial risk to fish in the Nashua River, and to birds and mammals exposed to the contents of the lagoon

Another benchmark presented in the list of preliminary remediation goals (PRGs) by Efroymson et al (1997) is a TCDD soil benchmark developed for the short-tailed shrew to represent risk to insectivorous mammals This benchmark is 0 00315 nanograms/kg, and it would be exceeded by all measured TCDD equivalents in the two lagoons

Based on the limited data available, there is reason to investigate surface water, sediment, and surface soil further for potential risk from inorganic and organic chemicals The source areas may pose a risk to terrestrial wildlife, and, should the lagoons be flooded, to aquatic life as well

9.0 DISCUSSION

Based on the data presented in the vanous source documents, the preliminary screening of surface water, soil and sediment indicates that risk may be present to receptors in the Nashua River, as well as to terrestrial organisms in the area of the site Concentrations of phenol, silver and zinc in surface water exceed relevant aquatic benchmark values for these chemicals Concentrations of cadmium, chromium, and lead in sediment exceed both LEL and SEL values, indicating potential risk to sediment organisms Soil data indicates the presence of 2,4,6-tnchlorophenol, pentachlorophenol, phenol, arsenic, copper, chromium, lead, and zinc that has the potential to be harmful to terrestrial receptors, in addition to total dioxm/furan concentrations that exceed both low and high risk levels for fish, birds and mammals The water and sediment benchmarks used are based on measured effects on pelagic and sediment-dwelling organisms Such organisms may be at risk when they forage in the Nashua River or surrounding upland areas, based on the screening performed on the limited data available

The source areas that would pose the greatest risk, based on the information available to data, would be Areas I and II, the two large lagoons near the Nashua River These lagoons have the greatest potential

to provide direct exposure to wildlife, and potential exposure to biota in the Nashua River.

10.0 REFERENCES

Efroymson RA, Will ME, Suter GW 1997 Toxicologies! Benchmarks for Screening Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process 1997 Revision Prepared for the U S Department of Energy, November, 1997 Publication Number ES/ER/TM-126/R2

Efroymson, R A , G W Suter, B E Sample, and D S Jones 1997 Preliminary Remediation Goals for Ecological Endpomts Prepared for the U S Department of Energy, Office of Environmental Management, August, 1997 Publication Number ES/ER/TM-162/R2

Environmental Reclamation, Inc 2001 Preliminary Sludge Characterization Report - Areas I and II ­Mohawk Tannery Site, Nashua, New Hampshire. January 11, 2001

GZA Goldberg-Zoino and Associates, Inc 1985 Phase II Hydrogeologic Study, Granite State Leathers, Inc., Nashua, New Hampshire.

New Hampshire Department of Environmental Services. 1996 Final Site Inspection Pnontization Report for Mohawk Tannery, Nashua, New Hampshire . CERCLIS No NHD981889629. November, 1996

New Hampshire Department of Environmental Services 1993 Mohawk Tannery Site, Expanded Site Inspection, Nashua, NH. December 29, 1993.

NUS Corporation. 1989. Final Screening Site Inspection Report for the Mohawk Tannery Facility, Nashua, New Hampshire July 5, 1989

Jaagumagi RD, Persaud, Bedard D 1995. Ontario's Approach to Sediment Assessment and Remediation. Second SETAC World Congress (16th Annual Meeting) Vancouver, British Columbia, Canada, November 5-9, 1995.

U.S. Environmental Protection Agency (USEPA). 2000. EPA Analytical Results from Recent Sampling Activities at the Mohawk Tannery Site in Nashua, NH. December 13, 2000.

U.S. Environmental Protection Agency (USEPA). 1999. National Recommended Water Quality Criteria -Correction. Office of Water. EPA/822/Z/99/001.

U.S. Environmental Protection Agency (USEPA). 1997. Ecological Risk Assessment Guidance For Superfund: Process for Designing and Conducting Ecological Risk Assessments, Interim Final. Environmental Response Team, Edison, New Jersey.

U.S. Environmental Protection Agency (USEPA). 1996. ECO Update: Ecotox Thresholds. Office of Solid Waste and Emergency Response (OSWER). EPA/540/F-95/038.

U.S. Environmental Protection Agency (USEPA). 1993. Interim Report on Data and Methods for Assessment of 2,3,7,8-Tetrachlorodibenzo-p-dioxin Risks to Aquatic Life and Associated Wildlife. Office of Research and Development. EPA/600/R-93/055.

U.S. Fish and Wildlife Service and New Hampshire Division of Public Health Services. 1987. Risk Assessment ofFuran Contaminated Fish in the Nashua River, Nashua, New Hampshire. PHS/FWS 87­2.

Van den Berg M, Birnbaum L, Bosveld ATC, Brunstrom B, Cook P, Feeley M, Giesy JP, Hanberg A, Hasegawa R, Kennedy SW, Kubiak T, Larsen JC, van Leeuwen FXR, Liem AKD, Nolt C, Peterson RE, Poellinger L, Safe S, Schrenk D, Tilhtt D, Tysklind M, Younes M, Waern F, Zacharewski T 1998 Toxic Equivalency Factors (TEFs) for PCBs, PCDDs, PCDFs for Humans and Wildlife Environmental Health Perspectives 106 775-792

Will ME, Sutler GW II 1995 Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants 1995 Revision Prepared for the U S Department of Energy, September, 1995 Publication Number ES/ER/TM-85/R2

Figure 1 Site Map

10

BOSTON UAJNE RAILROAO

AREjMEXISTING LAGOOH

LEGEND MONITORING (SCREENED INTERVAL UNKNOWN)

-*-*• FENCE GRASS ft TREE

A - SLUDGE CLARIFYING

• - SLUDGE OEWATERING UNOEVOOPCD LAND UNIT

"stSfefe*" * * " " » " * PROPERTY

BUODtNG NOT TO SCALE - NAStTSTORACE TANK

ADAPTED FROM NUS SITE SKETCH

SITE SKETCH MOHAWK TANNERY NASHUA, NH. FIGURE 2

11

Tables

12

Table 1

Screening of Organic and Inorganic Chemicals in Surface Water Mohawk Tannery, Nashua, New Hampshire

Acute Chronic Chemical Concentration^!) Benchmark (2) BBenchmarkJ3^

Organics ug/L Methylene Chloride 177 26,000 2,200

Phenol 2500 2,000 110 Inorganics ug/L

' Arsenic 2 66

Silver 60 4.1

Zinc 132 120 120

NOTES: (1) value is the concentration reported in the single NPDES water sample from the SIP report. (2) values for silver and zinc are the AWQC (EPA, 1999) CMC and CCC values. For methylene chloride and arsenic, Tier II secondary acute and secondary chronic values were used, assuming arsenic in the form of arsenic V. For phenol, ambient water quality criteria from the Great Lakes Initiative (cited in Suter and Tsao, 1996) were used. — = Not Available - no criterion for this chemical

= Indicates that the contaminant concentration exceeds the low benchmark at this station

bold text = Indicates that the contaminant concentration exceeds the high benchmark at this station

Table 2

Screening of Inorganic Chemicals in Sediment Mohawk Tannery, Nashua, New Hampshire

Maximum Concentration

Chemical ug/g dry wt. (1) SEL (2) , LEL13)

Cadmium 18,700 10 0.6

Chromium 313,000 110 26

Lead 163,000 250 31

Notes: (1) Maximum concentration among the NHDES sediment samples from

the Nashua River presented in the SIP report. (2) SEL = Severe Effect Level from Jaagumagi et al (1995). (3) LEL = Lowest Effect Level from Jaagumagi et al (1995).

= Indicates that the contaminant concentration exceeds the low benchmark

at this station. bold text = Indicates that the contaminant concentration exceeds the high benchmark

at this station. Jaagumagi, R., D. Persaud and D. Bedard. 1995. Ontario's Approach to Sediment Assessment and Remediation. Second SETAC World Congress (16th Annual Meeting) Vancouver, British Columbia, Canada, November 5-9, 1995.

Table 3

Screening of Inorganic Chemicals in Soil Mohawk Tannery, Nashua, New Hampshire

(all values expressed in parts per million (ppm) Maximum Detected Lowest Preliminary

Chemical Concentration (3) Remediation Goal (4) Organic Chemicals (1)

— Methylene Chloride 029 ~~ Tnchloroethylene 038

Toluene 93 200

Chlorobenzene 021 40

Acetone 36 —

2-butanone 078 2,4,6-trichlorophenol 140 4

Pentachlorophenol 510 3

Phenol 50 30

Inorganic Chemicals (2) Arsenic 21 99

Copper 74 60

Chromium 52140 04

Lead 193 405

Zinc 503 8.5 , Notes­(1) Concentrations detected in soil borings from various source areas

on site, reported by GZA (1985) (2) Concentration detected in soil samples from Areas I and II (lagoons)

reported by EPA (2000) (3) Value presented is the maximum detected concentration among

soil samples from the vanous source areas, in parts per million (4) The lowest PRO from Efroymson et al (1997) is presented This represents

the lowest value from the soil invertebrate, plant, and wildlife PRGs prepared for the Oak Ridge National Laboratory

— indicates that no benchmark was available for the chemical = Indicates that the contaminant concentration exceeds the benchmark

for this chemical. bold text = Indicates that the contaminant concentration exceeds the benchmark for both

terrestrial plants and earthworms at this location

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