hiteman b f uo

Superfund Proposed Plan

Hiteman b f uo Herkimer County, New York SDMS Document

Region 2 112266

AuQust 2006

PURPOSE OF THIS DOCUMENT

his document describes the remedial alternatives considered for the Hiteman Leather Company Superfund site and identifies the preferred remedy with the rationale for this preference. This Proposed Plan was developed by the'U.S.

Environmental Protection Agency (EPA) in consultation with the New York State Department of Environmental Conservation (NYSDEC). EPA is issuing this Proposed Plan as part of its public participation responsibilities under Section 117(a) of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, and Sections 300.430(f) and 300.435(c) of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). The nature and extent of the contamination at the site and the remedial alternatives summarized in this Proposed Plan are described in the February 2005 Remedial Investigation (Ri) report and August 2006 Feasibility Study (FS) report, respectively. EPA and NYSDEC encourage the public to review these docunients to gain a more comprehensive understanding ofthe site and the Superfund activities that have been conducted at the site.

This Proposed Plan is being provided as a supplement to the RI/FS reports to inform the public of EPA and NYSDEC's preferred remedy and to solicit public comments pertaining to all of the remedial alternatives evaluated, including the preferred soil, sediment, and groundwater alternatives. EPA and NYSDEC's preferred remedy consists of excavation of contaminated soil hot spots from the former tannery property, excavation/dredging of contaminated wetland and river sediments located adjacent to the former tannery property, solidification' and consolidation of the excavated/dredged soils and sediments on the former tannery property, soil cover, and intermittent groundwater extraction and treatment.

In order to appropriately balance the magnitude of the impacts of remediation with the reduction of ecological risk, excavation/dredging of river sediments in areas downstream of the former tannery property would be evaluated based on an assessment of sediment concentrations and the potential ecological impacts.

The remedy described in this Proposed Plan is the preferred remedy for the site. Changes to the preferred remedy, or a change from the preferred remedy to another remedy, may be made if public comments or additional data indicate that such a change will result in a more appropriate remedial action. The final decision regarding the selected remedy will be made after EPA has taken into consideration all public comments. EPA is soliciting public comment on all of the alternatives considered in the Proposed Plan and in the detailed analysis section ofthe RI/FS report because EPA and NYSDEC may select a remedy other than the preferred remedy.

Solidification employs the addition of cement additives to change the physical and chemical characteristics of a waste In order to immobilize contaminants.

iVIARK YOUR CALENDAR

Augus t 22, 2006 - September 21 , 2006: Public connnnent period related to this Proposed Plan.

Augus t 29, 2006 at 7:00 P.M.: Public meeting at the Village of West Winfield Free Library, South Street, WestWinfield, NY. n

I ':Ti.ri??gigf»^sPsgiisrl

COMMUNITY ROLE IN SELECTION PROCESS

EPA and NYSDEC rely on public input to ensure that the concerns of the community are considered in selecting an effective remedy for each Superfund site. To this end, the Rl and FS reports and this Proposed Plan have been made available to the public for a public comment period which begins on August 22, 2006 and concludes on September 21 , 2006.

A public meeting will be held during the public comment period at the West Winfield Free Library on August 29, 2006 at 7:00 p.m. to present the conclusions of the RI/FS, to elaborate fu r the r on the reasons for recommending the preferred remedy, and to receive public comments.

Comments received at the public meeting, as well as written comments, will be documented in the Responsiveness Summary Section of the Record of Decision (ROD), the document which formalizes the selection of the remedy.

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Superfund Proposed Plan Hiteman Leather Site

Written comments on the Proposed Plan should be addressed to:

Jack O'Dell Remedial Project Manager

Central New York Remediation Section U.S. Environmental Protection Agency

290 Broadway, 20th Floor New York, New York 10007-1866

' Telefax: (212)637-3966 Internet: [email protected]

SCOPE AND ROLE OF ACTION

The primary objectives of this action are to remediate the sources of soil, sediment, and groundwater contamination, to minimize the migration of contaminants, and to minimize any potential future health and environmental impacts.

SITE BACKGROUND

Site Description

The Hiteman Leather Company site (hereinafter, the "former tannery property") is a former tannery and leather

>manufacturing facility located in the Village of West Winfield at 173 South Street (Route 51) just south ofthe intersection of Route 51 with State highway Route 20. The former tannery property, currently owned by the Village of West Winfield, is bordered to the north by commercial buildings and residences, to the east by South Street, to the south by a residential property and a small tributary to the Unadilla River, and to the west by the West Winfield Cemetery. The former tannery property is approximately 12 acres in size and is traversed by approximately 800 feet of the Unadilla River. Ten acres are located on the northern bank of the river and 2 acres are located on the southern bank, which fronts on South Street. A landlocked privately-owned 2-acre parcel is located to the rear. (See Figure 1).

On the 10-acre portion of the former tannery property, two former tannery buildings are located in the northeast. One of these, a metal shed, is currently used by the Village of West Winfield Department of Public Works (DPW) for storage and as a garage. The other building is a small concrete shed, which is unused. Foundation remriants ofthe former tannery buildings {i.e., the tannery buildings were demolished) and a macadam parking lot are located in the southeast along South Street. A 2-acre area, where three former wastewater lagoons (each approximately 50 feet wide by 350 feet long), now leveled and backfilled, is located to the west behind the former buildings. To the far west is a

J.8-acre wetland. A 4-acre open field area lies in the northern and middle part of this 10-acre area. Most of the 10-acre area is fenced, whereas the southern part of the site is unfenced, undeveloped, low lying and thinly-wooded, with

a small open field area. A small, inactive horse barn is located on the rear parcel.

Geographically, the site is located within the Unadilla River valley, the floor of which has relatively low topographic relief. West Winfield is located on the northern edge of the approximately one and one-half mile wide Unadilla River valley, which is oriented west southwest-east northeast and slopes slightly (approximately 0.28 percent slope) to the southwest in the vicinity of the site. The river valley is bounded abruptly to the north and south by rolling hills with elevations between three and five hundred feet above the valley floor.

The topography of the former tannery property is mostly flat,! with a gentle southwestern slope from the northeastern and eastern portions ofthe site toward the southwestern wetland area and the Unadilla River. The area once occupied by the former wastewater lagoons has no topographic expression other than small mounds and hummocks. The surface expression of a possible former channel leading from the northernmost former lagoon to the wetlands, observed in historical aerial photographs, can be identified visually. Along the Unadilla River, the northern river bank drops steeply (betw^een six and 8 feet) down to the river. Riprap was placed along an approximately 600-foot section of this bank, as an erosion control measure by EPA in 1996. The 2-acre southern portion ofthe site is level. Ground surface elevations range from approximately 1,170 to 1,180 feet above mean sea level.

Site History

The West Winfield tannery was established on the northern bank ofthe Unadilla River in 1820 by a Mr. Adsit. In 1910, after several changes in ownership, the tannery business was acquired by the Hiteman family and the name of the business was later changed to the Hiteman Leather Company. In 1922, the company was officially reorganized as a corporation under the name of Hiteman Leather Company, Inc., with the name remaining unchanged until the termination of the business in 1968.

In the leather tanning process, animal hides and skins absorb chemicals that prevent the resulting leather from decaying, make it resistant to wetting, and keep it supple and durable. Originally, tree bark extract (containing tannins) was used; later chromium salts were also used.

Waste was originally discharged from the tannery buildings directly to the Unadilla River. Under the Hiteman family, the tannery and tannery property experienced many changes over the years to expand business and increase production, including a major change during the early 1900s to incorporate chromium-based tanning into the process. The chromium-based process, in combination with mechanization, reduced the time to manufacture leather from years to months to weeks; however, the wastes that were generated were more toxic and far more voluminous,

EPA Region II - August 2006 1 0 . 0 0 0 3 9

mailto:[email protected]


resulting in the construction of two unlined lagoons in 1931 and a third unlined lagoon in 1959. Berms were constructed

karound the lagoons to increase their capacity. Wastewater 'was discharged via a sluiceway to the lagoons. The wastewater lagoons reportedly discharged to the Unadilla River and to the wetland area to the northwest of the lagoons (which ultimately drains to the Unadilla River). Wastewater from the coloring process was discharged into two 240 cubic-foot concrete dye tanks prior to being discharged to the Unadilla River. Sludge from the bottom of the lagoons was periodically dredged and was reportedly deposited as berm material surrounding the lagoons.

The inability to economically treat contaminated wastewater from the tannery forced the closing of the Hiteman Leather Company in 1968. The property and buildings were sold in 1969 to Erie Davis of Clinton, New York, who subsequently rented the buildings to various small businesses during the 1970s (mostly for storage), including a cookie company and a tire company. The tannery buildings were no longer occupied after 1982 and they gradually deteriorated.

Discarded hides, hide scrapings and shavings, and other tannery wastes were reportedly disposed of in the Village of West Winfield Dump, located approximately 1/3 mile to the southeast of the former tannery property. The 2.5-acre Crumb Trailer Park now overlies the former dump. While a preliminary investigation of the trailer park was commenced during the RI/FS, additional data are required. Accordingly,

|potential response actions with respect to the trailer park were not assessed in this Proposed Plan. A determination as to whether or not the tannery wastes disposed of in the dump pose a threat to the residents of the trailer park will be assessed in the near future through EPA's Emergency Response and Removal Program. This program protects the public and the environment from immediate threats posed by hazardous substances and oil.

The site was added to the New York State Registry of Inactive Hazardous Waste Sites in 1985. Several New York State investigations were conducted at the site during the 1980s. The New York State Department of Environmental Conservation (NYSDEC) conducted an investigation ofthe site from 1988 to 1992, which resulted in the site being referred to EPA for further evaluation. In 1994, EPA performed some preliminary sampling at the former tannery property and fenced the northern part of the site to prevent unauthorized access, particularly to the deteriorating buildings.

In 1996, EPA conducted a site investigation and found asbestos-covered pipes throughout the main tannery building. It was also determined that the wood-frame sections ofthe building were structurally unsound. Based on this evaluation, EPA conducted an asbestos removal and

^demolished the wood frame sections of the building, power louse, and chimney stack in 1996. The remaining concrete and steel building was demolished by the Davis estate in 1998, with the latter demolition leaving piles of loose brick

EPA Region II - August 2006

and concrete debris, as well as other concrete remnants {e.g., building pillars, concrete dye tanks\ etc.). Much ofthe loose debris was removed from the concrete foundation floor by EPA in May 2001 to facilitate sampling under the floor.

In 1999, the site was listed on EPA's Superfund National Priorities List.

EPA conducted a field investigation at the Hiteman Leather site in 2001-2002 to acquire data for the Rl. Field investigation activities involved geological and hydrogeological investigations (including monitoring well installation) and environmental sampling, which included the collection of samples from surface soil (top two feet of soil), subsurface soils (below two feet), wetland sediment, surface water and sediment from the Unadilla River, fish tissue, groundwater, residential wells, and public supply wells. Associated activities included a surface features investigation (including site base map preparation), synoptic water level measurements, an ecological assessment, a wetlands delineation, and a cultural resources survey.

The Village of West Winfield acquired the former Hiteman Leather tannery property in 2003.

In 2004, a variety of samples were collected to support a Baseline Ecological Risk Assessment (BERA), including biological samples, soil and sediment for toxicity tests, and additional surface water and sediment samples from downstream areas ofthe river {i.e., locations along a 7,000-ft reach). Supplemental groundwater sampling was performed at the site during 2006.

The Village of West Winfield is currently supplied with potable water from two water supply wells located north, of Route 20, but within the Village limits. The wells are approximately 1,700 feet northeast (upgradient) of the former tannery property.

In 2003, EPA awarded a $100,000 federal grant to the Village of West Winfield to develop a Reuse Assessment and Redevelopment Plan for the Hiteman Leather site as part of the EPA's Superfund Redevelopment Initiative^. The Village's Reuse Assessment and Redevelopment Plan^, calls for the construction of a community center, development of recreational facilities, consolidating and modernizing the existing DPW facility, and commercial development.

The Hiteman Leather Company reportedly cleaned the the dye tanks before it closed the facility.

The Superfund Redevelopment Initiative is a nationally coordinated effort to restore toxic waste sites to productive reuse.

Reuse Assessment and Redevelopment Plan for the Hiteman Leather Superfund Site, Village of West Winfield, New York, February 2006.

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SITE HYDROLOGY/HYDROGEOLOGY

kSite Hydrology

The Hiteman Leather site is located in the northern portion of the Appalachian Upland physiographic province, which includes the Unadilla River valley. Local surface water runoff flows toward the Unadilla River, which traverses the former tannery property from the Route 51 bridge at the eastern edge to the outflow of the wetland area on the western side of the property. The Unadilla River in the area where it crosses the former tannery property is classified by New York State as a "Class C(T)" stream. The best usage of Class C waters is fishing. These waters shall be suitable for fish propagation and survival. The water quality shall be suitable for primary and secondary contact recreation (6 NYCRR Part 701.8)., The symbol (T) after any class designation means that the designated waters are trout waters, and that the dissolved oxygen specification for trout waters shall apply (6 NYCRR Part 931.2(g)).

The former tannery property is located in a 500-year flood plain and according to the Federal Emergency Management Agency, approximately sixty percent of the site is in a 100-year flood plain.

Site Hydrogeology

rHydrogeologic data indicate a highly complex hydrogeologic system governed by artesian conditions, seasonal variations, and the presence of natural and man-made surface water bodies. It is likely that several factors, including historic tannery practices, altered the natural flow of groundwater underlying the former tannery during its operation. The hydrogeology is characterized by the existence of three hydrogeologic units described below.

The limestone bedrock unit underlying the former tannery property comprises the bedrock aquifer; groundwater flow in this unit is through joints and bedding planes, which were observed to be wider and more numerous near the bedrock surface. The bedrock aquifer is semi-confined by the glacio-lacustrine deposits, resulting in artesian conditions in wells completed in this unit. Groundwater in the bedrock aquifer beneath the former tannery property has a dominant upward flow direction with a minor west/southwest component.

The glacio-lacustrine semi-confining unit overlies the bedrock aquifer. These fine-grained deposits create a leaky, semi-confining unit, separating the underlying bedrock aquifer from the shallow outwash aquifer above. Despite its lower permeability, the unit is water-producing (although it is not very productive). According to water level data in deep wells, the horizontal flow in this unit is to the southwest. In

kaddition, there is a seasonal upward vertical gradient through This unit, suggesting a hydrological connection between this unit and the bedrock aquifer.

The shallow outwash aquifer unit overlies the glacio-lacustrine semi-confining unit and is composed of glacial outwash and fluvial sediments, and fill material. This aquifer is unconfined, and unlike the lower units, does not exhibit artesian conditions. Water table depths vary seasonally, but generally ranged from three to 18 feet below ground surface during 2001-2002. Groundwater flow in the shallow aquifer is to the southwest.

RESULTS OF THE REMEDIAL INVESTIGATION

Based upon the results of the Rl, EPA has concluded that metals are the predominant contaminants in the soils in the northern 10 acres of the former tannery property and in sediments in the wetland and in the Unadilla River. Although a number of organic compounds were detected at the former tannery property, they appeared to be incidental, were found only infrequently and at relatively low concentrations, and/or could not be attributed to site activities. The contaminants of concern (COCs) identified for the site include antimony, arsenic, cadmium, chromium, hexavalent chromium, lead, manganese, mercury, and nickel.

The first step in evaluating the nature and extent. of contamination at and emanating from the site was to identify regulatory standards and criteria to assess and screen detected constituents in the various sampled media. Second, results from background, or upgradient samples that were collected for each sampled media were evaluated and compared to data from environmental or downgradient samples.

Soils

There are currently no federal or state promulgated standards for contaminant levels in soils. There are, however, other federal or state advisories, criteria, or guidance (which are used as "To-Be-Considered" [TBC] criteria), one of which is the New York State Technical and Administrative Guidance Memorandum No. 94-HWR-4046 (TAGM) objectives", which NYSDEC consistently applies as a basis for addressing contaminated soils. TAGM objectives are the more stringent cleanup level between a human health protection value, a value based on protection of groundwater, or background concentrations. The applicable TAGM objectives for the former tannery area soils are summarized in Table I , below.

The human health protection values that are being used as TBCs for this site are derived from a variety of sources, including human health protection TAGM objective values, site background, and site-specific risk-based calculations.


Division Technical and Administrative Guidance Memorandum: Determination of Soil Cleanup Objectives and Cleanup Levels, Division of Hazardous Waste Remediation, January 24, 1994.

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The human health protection values that are being used are summarized in Table 1, below.

' A total of-26 surface soil samples and 75 subsurface soil samples were collected from 30 soil borings on the former tannery property. Surface soil samples were collected at each boring from the 0-2-foot depth interval. Subsurface soil samples were collected from multiple depth intervals at each boring location ranging from the 2-4-foot interval to the 8-10-foot interval. In the lagoon area, several samples were collected to depths of 18-20 feet.

Dark gray-to-black material, which appears to have resulted from the tree bark extract {i.e., lignins and tannins) used in the non-chromium tanning process, was observed at approximately two to 5 feet below the ground surface in the area ofthe former wastewater lagoons. This material, which was 1- to 6-inch thick, was only observed in the shallow aquifer. The levels of metals detected in this material were no greater than those detected in lighter-colored soils.

All of the COCs identified for the site were found in the former tannery property's surface soil samples (0-2ft) and the subsurface soil samples (below 2-ft). While the highest contaminant concentrations in each soil strata were comparable, in general, the majority of the detections and high concentrations were found less than 5 feet from the surface.

• T he highest concentrations found in the surface and subsurface soils for each of the COCs detected 'above applicable criteria are summarized in Table 1, below.

The location of the most frequent excursions above the human health protection values in both surface and subsurface soil includes an area southwest of the former building footprint, between the former building footprint and the Unadilla River, where a sluiceway and underground storage tank were located. Other areas of elevated COC contamination in surface and subsurface soil include the eastern part of the former lagoons (where wastewater entered the lagoons), along the northern bank of the river, and in the west-central part of the former tannery property (adjacent to the wetlands, where lagoon overflow was directed to the on-site wetland through a former weir box).

Table 1 COMPARISON OF SOIL CONCENTRATIONS AND

CLEANUP OBJECTIVES

Contaminant of

Concern

Antimony

Arsenic

Cadmium

Maximum Concentrations '

Detected (mg/kg)

260

45

11.8

TAGM Objectives

(mg/kg)

ND

10.2

1

Human Health

Protection Values (mg/kg)

31

N/A

N/A

Chromium

Lead

Manganese

Nickel

75,800

849

1,090

60.8

18.8

13.2

554

25.4

N/A

N/A

554

N/A

Key: ND= Not Detected • N/A=Not applicable (does not pose an increased cancer or noncancer risk)

Sediments

There are currently no federal or state promulgated standards for contaminant sediments. Similar to soils, there are, however, TBC criteria, one of which is NYSDEC's sediment screening values^. During the design phase, Unadilla River sediment background concentrations would be reassessed. Contaminated Unadilla River sediments would be remediated based upon the sediment screening values (LELs) noted in Table 2, below, or sediment background concentrations, if appropriate.

Seventeen sediment samples were collected from five depositional areas in the Unadilla River (one adjacent to the former tannery property and four downstream areas; the furthest downstream depositional area is located 1.2 miles from the former tannery property) to an average depth of 6 inches (a rocky river bottom limited the sampling depth). The highest concentrations found in the Unadilla River sediments for each of the COCs detected are summarized in Table 2, below.

Table 2 COMPARISON OF RIVER SEDIMENT CONCENTRATIONS

AND SEDIMENT SCREENING VALUES

Contaminant of Concern

Antimony

Arsenic

Cadmium

Maximum Concentrations

Detected in Unadilla River

Sediments (mg/kg) ^

15

7.2

0.54

Sediment Screening Values

Lowest Effect Levels (mg/kg)

2

6

0.6

Severe Effect Levels (mg/kg)

25

33

9


NYSDEC's sediment screening values are specified in its Division of Fish and Wildlife, Division of Marine Resources, Technical Guidance for ""Screening Contaminated Sediments, January 1999. The guidance identifies two levels of risk for metals contamination in sediments. These are the Lowest Effect Level (LEL) and the Severe Effect Level (SEL). A sediment is considered contaminated if either criterion is exceeded. If both criteria are exceeded, the sediment is considered to be severely impacted. If only the LEL criterion is exceeded, the impact is considered moderate.

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Chromium

Copper

lead

Mercury

Nickel

1,670

22.7

58.3

0.25

18.8

26

16

31

0.15

16

110

110

110

1.3

50

Sediment samples were collected from two depths (0-6 inches and 18-24 inches) at 15 locations within the wetland. The highest concentrations found in the wetland sediments (0-2ft) for each of the COCs detected are summarized in Table 3, below. Since the ecological risk related to the wetland sediments is to burrowing animals, an excavation depth of 3 feet will be used for purposes of remediation.

Table 3 WETLAND SEDIMENT CONCENTRATIONS


<

Antimony

Arsenic

Cadmium

Chromium

Copper

Lead

Mercury

Nickel

Maximum Concentrations Detected in Wetland Sediments

(mg/kg)

795

188

6.2

89,900

635

316

0.82

30.8

Surface Water

New York State has promulgated surface water quality criteria, New York State Ambient Water Quality Standards and Guidance Values and Groundwater Effluent Limitations. The criteria for the COCs for Class C surface waters (trout propagation, fishing, and recreation) are summarized in Table 4, below.

Surface water samples were collected at fourteen of the locations in the Unadilla River where sediment deposits were obtained. No COCs were detected above the water quality standards (see Table 4, below).

Table 4 COMPARISON OF SURFACE WATER

CONCENTRATIONS AND WATER QUALITY CRITERIA



Detected in Surface Water

(MQ/I)

Surface Water Quality Criteria

(MQ/I)

Arsenic

Cadmium

Chromium

Copper

Hexavalent Chromium

Lead

Mercury

Nickel

ND

ND

ND

ND

ND

ND

ND

ND

150

2.09

74.1

8.96

11

3.78

0.77

52

Key: pg/l = microgram per liter ND=Not detected

Groundwater

- EPA and New York State Department of Health have promulgated health-based protective Maximum Contaminant Levels (MCLs), which are enforceable standards for various drinking water contaminants. MCLs, which ensure that drinking water does not pose either a short- or long-term health risk, will be used as the cleanup criteria for the groundwater. Table 5, below, summarizes the MCLs for the COCs.

Groundwater samples were collected from 21 monitoring wells. Samples from the bedrock aquifer never exceeded MCLs. While there were MCL exceedances in the shallow aquifer during early sampling rounds, these samples were highly turbid. Subsequent samples with lower turbidity did not exceed MCLs. MCLs were, however, exceeded in the semi-confining unit in three wells (north central, southwest, and immediately south of the Unadilla River). The highest concentrations found in these wells for each of the COCs. detected are summarized in Table 5, below.

Table 5 COMPARISON OF GROUNDWATER CONCENTRATIONS

AND GROUNDWATER STANDARDS


Arsenic

Chromium

Lead

Nickel


Detected in Groundwater

(ug/i)

184

240

176

323

Groundwater Standards

(ug/i)

10

100

15

100

Key: pg/l = microgram per liter

With the exception a monitoring well which is located adjacent to the wetland, the monitoring wells screened in the semi-confining unit are artesian (upward flowing).


Super fund P roposed Plan H i teman Leather Site

M

WHAT IS RISK AND HOW IS IT CALCULATED? I

A Superfund baseline human health risk assessment is an-analysis of the potential adverse health effects caused by hazardous substance releases from a site in the absence of any actions to control or mitigate these under current- and future-land uses. A four-step process is utilized for assessing site-related human health risks for reasonable maximum exposure scenarios.

Hazard Identification: In this step, the COCs at the site in various media (/.e., soil, groundwater, surface water, and air) are identified based on suchfactdrs as toxicity, frequency of occurrence, and fate and transport of the contaminants In the environment, concentrations,of the contaminants in specific media, mobility, persistence, and bioaccumulation.

Exposure Assessment: In this step, the different exposure pathways through which people might be exposed to the contaminants.identified in the previous step are evaluated. Examples of exposure pathways include incidental ingestion of and dermal contact with contahiinated soil. Factors relating to the exposure assessment include, but are not limited to, the concentrations that people might be exposed to and the potential frequency and duration of exposure. Usihg these factors, a "reasonable maximum exposure" scenario, which portrays the highest level, of human exposure that could reasonably be expected to occur, is calculated. '

Toxicity Assessment: In this step, the types of adverse health effects associated with chemical exposures, and the relationship between magnitude of exposure and severity of adverse effects are determined. Potential health effects are chemical-specific and may include the risk of developing cancer over a lifetime or other non-cancer health effects;, such as changes in the ndrmalfunctions of organs within the body (e.g., changes in the effectiveness of the imhiune system). Some chemicals are capable of causing both cancer and noncancer health effects. ;. :•'••••:''''.. • \ .

Risk C/jaracterizaf/on.- This,step summarizes and combines outputs ofthe exposure and toxicity assessments to provide a quantitative assessmentofsite risks. Exposures are evaluated based on the potential risk of developing cancer iand the potential for non-cancer health hazards. The likelihood of an individual developing cancer Is expressed as a probability. For example, a 10"" cancer risk rneans a "one-in-ten-thousand excess cancer risk"; or one additional cancer ma^ be seen in a [Dopulation of 10,000 people as a result of exposure to site contaminants under the conditions explained in the Exposure Assessment. Current Superfund guidelines for acceptable exposures are an individual lifetime excess cancer;risk\in the range of 10"" to 10"® (corresponding to a orie-|n-ten-thousand to a one-in-a-miliion excess;cahcer risk) with 10"° being;the point of departure. For non-cancer health effects, a "hazard Index" (HI) is calculated. An HI represents the sum ofthe individual exposure levels compared to their, corresponding reference doses. The key concept for a non-cancer HI is that a:."thresh6ld level" (measured as an HI of less than 1) exists below which non-cancer health effects are not expected to occur.

The detection of contamination in the semi-confining unit is attributable to suspended colloidal particulates in the samples, as contaminants were only found in the unfiltered, highly turbid samples (the results from the filtered samples did not exceed the MCLs).

The unusual pattern of contaminants {i.e., contaminants only being present in the semi-confining unit) might be explained as follows. While the tannery was in operation, contaminants flowed into the shallow glacial aquifer, deep glacial semi-confining unit, and possibly into the bedrock aquifer while under hydraulic pressure from the lagoons. Those.conditions no longer exist at the site {i.e., the lagoons have been backfilled with soil and the berms have been leveled) and that migration pathway has been eliminated. It was also determined that the metal contaminants are' tightly bound to the soil particles, which limits their mobility into the groundwater.

Based upon the data, EPA has also concluded that there is no horizontal migration of groundwater contaminants at the site, as is indicated by the lack of a groundwater plume. The data also indicate that there is no current upward migration of contaminants at the site from the semi-confining unit to the shallow aquifer, despite artesian conditions. In addition, the semi-confining unit (the only strata where contamination was detected above MCLs) is not a very productive unit, as many of the deep monitoring wells were pumped dry during low-flow sampling.

SITE RISKS

Based upon the results ofthe Rl, a baseline risk assessment was conducted to estimate the risks associated with current and future property conditions. A baseline risk assessment is an analysis of the potential adverse human health effects caused by hazardous-substance exposure in the absence of any actions to control or mitigate these under current and reasonably anticipated future land uses.

The human health estimates summarized below are based on current reasonable maximum exposure scenarios and were developed by taking into account various conservative estimates about the frequency and duration of an individual's exposure to the COCs, as well as the toxicity of these contaminants.

A screening level ecological risk assessment (SLERA) was also conducted to assess the risk posed to ecological receptors due to site-related contamination, which resulted in the performance of a BERA, which is discussed below.

Human Health Risk Assessment

As was noted above, the former tannery property is currently being used by the Village of West Winfield DPW for storage and as a garage. It is anticipated that the land use in the future will be recreational/commercial.



m

The baseline risk assessment began with selecting COCs in the various media that would contribute to site risks. Since

I the area is served by municipal water, it is not likely that the groundwater underlying the former tannery property will be used for potable purposes in the foreseeable future; however, since regional groundwater is designated as a drinking water source, potential exposure to groundwater was evaluated.

COCs in the groundwater include antimony, arsenic, chromium, lead, and nickel. While risk calculations related to the groundwater were not undertaken, groundwater concentrations in. the semi-confining unit for these contaminants exceeded MCLs, indicating a potential health risk.

Several exposure pathways and receptors were identified during the risk assessment. A review of the carcinogenic risks for exposures to former tannery property soils and wetland and river sediments showed that all of the carcinogenic risks were within the acceptable risk range {I.e., no excess lifetime cancer risks exceeded the EPA threshold of lO""). Specifically, the risk posed by surface soils to an adolescent trespasser on the former tannery property under the current-use scenario posed an increased cancer risk of 6.4x10"^. The future-use scenario poses an increased cancer risk of 2x10'® to construction workers exposed to subsurface soils.

fwith regard to non-cancer effects. His exceeded the EPA threshold of one for several scenarios. Under the former tannery property future-use scenario, the HI for a child recreational user exposed to surface soils (top two feet of soil) is 2.6 and the HI for a construction worker exposed to dust from the subsurface soils (at a four-foot depth at one location) is 5.

Ecological Risk Assessment

Ecological communities identified on the former tannery property include old-field habitats, emergent/scrub-shrub/forested wetlands, semi-maintained grass areas, and urban/disturbed areas. Wooded areas were limited to thin bands of trees and shrubs along the property's boundaries, and isolated thin hedgerows within the interior of the property.

The former tannery property is separated from the Unadilla River and neighboring natural areas by an 8-foot high chain-link fence. The presence of the fence limits the use of the property as a habitat resource by large mammals. It is, however, utilized as a habitat resource by smaller mammals. Avifauna utilize the property as a habitat resource. During the ecological reconnaissance, several passerine species were observed. No raptors, waterfowl, wading birds, reptiles, or amphibians were observed. The wetlands do not support

dequate surface water resources to provide year-round habitat for fish. While predators were not observed, it is

possible that hawks, owls, shrews, mink, weasels, raccoon, skunk, and fox hunt in the fields and edge communities.

There are no known occurrences of rare or state-listed animals or plants, significant natural communities, or other significant habitats, federally-listed threatened or endangered species or habitats of special concern within a two-mile radius of the former tannery property. No known threatened and endangered species were observed.

As part of the Rl, a SLERA was conducted. The results of the SLERA indicated the potential for risk to ecological receptors from site-related contaminants. EPA concluded that a more thorough assessment of ecological risk {i.e., a BERA) was warranted. The BERA used a multiple lines-of-evidence approach to evaluate ecological risks, including food chain modeling, site-specific toxicity testing, and field observations (such as the lack of amphibians in the wetland).

The BERA focused on both the aquatic communities exposed to contaminants in the Unadilla River and the terrestrial organisms exposed to contaminants in the on-property wetland sediment and upland surface soil at the site.

The BERA identified the potential for ecological risks from exposure to chemicals detected in the Unadilla River sediment, wetland sediment, and former tannery property surface soil. Metals drove the risk calculations, showing a high (greater than unity) Hazard Quotient (HQ)^ attributable to the metals in these rnedia.

The BERA determined that contaminated Unadilla River sediments had a negative impact on invertebrate aquatic organisms. High concentrations of metals in wetland sediments and former tannery property surface soils along an 800-foot long, 20-foot wide strip along the top of the northern bank of the river pose significant risks to plants, soil microbes, and invertebrates in these media. In addition, terrestrial invertivore and terrestrial omnivorous avian species with small home or foraging ranges are also impacted by ingesting invertebrates that inhabit contaminated media.

Although the BERA did not calculate the risk to muskrats, it is believed that contaminated soils along a 225-foot unriprapped portion ofthe side ofthe northern riverbank may pose a threat to muskratS:

Summary of Human Health and Ecological Risks


An HQ Is a ratio of a measured or modeled exposure to an effect concentration considered to represent a "safe" environmental concentration or dose. There is a potential for risk associated with HQs greater than 1.

1 0 . 0 0 0 4 5 ^


The results of the risk assessment indicate that former tannery property soil hot spots present unacceptable

^increased non-cancer hazards. Contaminated soils along the 'river on the former tannery property area and contaminated wetland and river sediments pose unacceptable ecological risks. In addition, inorganic groundwater concentrations in the semi-confining unit exceed their respective MCLs, thereby posing a potential human health risk.

Based upon the results of the Rl and the risk assessment, EPA has determined that actual or threatened releases of hazardous substances from the site, if not addressed by the preferred remedy or one of the other active measures considered, may present a current or potential threat to human health and the environment.

pollutants and contaminants at a site. CERCLA §121 (d), 42 U.S.C. §9621 (d), further specifies that a remedial action must attain a level or standard of control of the hazardous substances, pollutants, and contaminants, which at least attains ARARs under federal and state laws, unless a waiver can be justified pursuant to CERCLA §121 (d)(4), 42 U.S.C. §9621 (d)(4).

Detailed descriptions of the remedial alternatives for addressing the contamination associated with the site can be found in the FS report. The FS report presents four former tannery property alternatives, three sediment alternatives, and three groundwater alternatives. To facilitate the presentation and evaluation ofthe alternatives, the FS report alternatives were reorganized in this Proposed Plan to formulate the remedial alternatives discussed below.

REMEDIAL ACTION OBJECTIVES

Remedial action objectives are specific goals to protect human health and the environment. These objectives are based on available information and standards, such as applicable or relevant and appropriate requirements (ARARs), to-be-considered guidance, and site-specific risk-based levels.

The following remedial action objectives were established for the site:

Reduceoreliminateanydirectcontact, ingestion, or inhalation threat to future recreational users or construction workers to contaminated soils and sediments;

Although the FS report evaluated a remedial alternative that included the excavation, solidification, and on-property disposal of all former tannery property soils that exceed TAGM objectives, it was eliminated from further consideration in this Proposed Plan since it was significantly more expensive (an estimated present-worth cost of $27,800,000) than the other action alternatives while providing no additional protection of public health or the environment.

The construction time for each alternative reflects only the time required to construct or implement the remedy and does not include the time required to design the remedy, negotiate the performance of the remedy with any potentially responsible parties, or procure contracts for design and construction.

Minimize exposure of wildlife or fish to contaminated soils and sediments;

• Protect human health by preventing exposure of future users to contaminated groundwater; and

• , Restore groundwater to levels which meet state and federal standards within a reasonable time frame.

Tables 1, 2, 4," and 5 summarize the soil, river sediment, surface water, and groundwater cleanup objectives, objectives, standards, and standards, respectively.

SUMMARY OF REMEDIAL AL TERN A TIVES

CERCLA §121 (b)(1), 42 U.s!c. §9621 (b)(1), mandates that remedial actions must be protective of human health and the environment, cost-effective, comply with ARARS, and utilize permanent solutions and alternative treatment technologies and resource recovery alternatives to the maximum extent practicable. Section 121 (b)(1) also establishes a preference for remedial actions which employ, as a principal element, treatment to permanently and significantly reduce the volume, toxicity, or mobility of the hazardous substances.

The remedial alternatives are:

Soil and Sediment Alternatives

Alternative S-1: No Action

Capital Cost:

Annual Operation, Maintenance, and Monitoring (OM&M) Cost:

Present-Worth Cost:

Construction Time:

$0

$0

$0

0 months

The Superfund program requires that the "no-action" alternative be considered as a baseline for comparison with the other alternatives. The no-action remedial alternative for soil does not include any physical remedial measures that address the problem of soil and sediment contamination at the property.

Because this alternative would result in contaminants remaining above levels that allow for unrestricted use and unlimited exposure, CERCLA requires that the site be



reviewed at least once every five years. If justified by the review, remedial actions may be implemented to remove,

^treat, or contain the contaminated soils and sediments.

Since the contaminated sediments in downstream areas are in remote locations, access to the sediments would require significant tree clearing, road construction, erosion control, and intrusion in wetland areas.

Alternative S-2: Contaminated Soil and Sediment Excavation/Dredging, Off-Site Treatment/Disposal, and Soil Cover

Capital Cost:

Annual OM&M Cost:

Present-Worth Cost:

Construction Time:

$15,036,000

$310,000.

$16,129,000

24 months

This alternative consists of the excavation of soil from three former tannery property hot spots that exceed human health protection values (Areas S I , S2, and S3) (see Figure 2). The two surface soil hot spots (Areas SI and S3)-would be excavated to a depth of 2 feet and the subsurface soil hot spot (Area S2) would be excavated to a depth of approximately 4 feet. The sluiceway would be excavated in conjunction with Area S3.

This alternative also includes the excavation of a surficial soil hot spot located to the east of Area SI (Area S8), soil from

^unsaturated zone (above the water table) soil hot spots' 'underlying Areas SI and S3, unsaturated zone soil hot spots underlying Area S2, an unsaturated zone soil hot spot located in the southeastern corner of the foundation remnants (Area S4), unsaturated zone soil hot spots located in the former lagoons (Area S5), an approximately 800-foot long, 20-foot wide contaminated strip along the top of the northern bank ofthe river along the former tannery property to a depth of 2 feet (Area S6), and a 225-foot unriprapped portion ofthe side ofthe northern riverbank along the former tannery property 5 feet laterally from the edge of the river (AreaS7).

In addition, contaminated Unadilla River sediments exceeding the sediment screening values or sediment background concentrations, if appropriate, would be dredged/excavated. Contaminated wetland sediments would be excavated to a depth of 3 feet.

The wetland areas containing small shrubs and dense vegetation would require clearing prior to excavation/dredging activities.

Unsaturated zone soil hot spots are defined as grossly-contaminated soil/material. To the extent practicable, excavation would occur during a low groundwater table period {i.e., July - November) with a goal of removing hot spots to a depth of 6 -7 feet or the groundwater table, whichever is deeper.


The estimated volume of contaminated soil to be excavated on the former tannery property is 11,000 cubic yards (CY). The estimated volumes of sediment to be remediated are 9,200 CY in the wetland and 2,400 CY in the Unadilla River. The actual extent of the excavation and the volume of the excavated material would be based on post-excavation confirmatory sampling.

The loose brick and concrete debris, as well as concrete remnants, including the concrete dye tanks, located on the former tannery property, would be decontaminated, if necessary. The concrete dye tanks will be demolished and removed. Any contaminated soils and sludges associated with the debris and concrete remnants would be excavated/removed.

All excavated soils and sediments, as well as any recovered sludges, would be characterized and transported for disposal (treatment may be required) at an off-site RCRA-compliant facility. Cleared , vegetation would be disposed at a nonhazardous waste landfill or could be mulched and used elsewhere on-site.

Water generated from dewatering the sediments and from collected runoff would be collected and treated on-site. It would be discharged into the Unadilla River in conformance with State Pollutant Discharge Elimination System (SPDES) requirements.

In former tannery property areas where residual soil contamination would exceed the TAGM objectives, a soil cover with a thickness of two feet would be placed in areas with "active" exposure potential and a thickness of one-foot in areas with "passive" exposure potential. "Active" and "passive" areas are based on the current future-use plan prepared for the Village of West Winfield.

Before placing the soil cover over areas where residual soil contamination would remain, a readily-visible and permeable subsurface demarcation delineating the interface between the native soil and the backfill would be installed.

The excavated areas would be backfilled with clean soil. The backfilled areas, as well as the soil cover, would be seeded with grass to stabilize the soil. The disturbed wetlands and river bed would also be restored.

All remedial work in the wetlands and river bed would need to comply with New York State Environmental Conservation Law Article 24 and 6 NYCRR Part 663 requirements, as well as Executive Order 11990, 40 CFR Part 6 Appendix A, "Statement of Procedures on Floodplains Management & Wetlands Protection," and Section 404 of the Clean Water Act.

1 0 . 0 0 0 4 7


The restored wetlands would require routine inspection for several years to ensure adequate survival of the planted

^vegetation. Replanting would be performed, if necessary.

Under this alternative, institutional controls in the form of an environmental easement and/or restrictive covenant would be used to restrict any excavation below the former tannery property's soil cover unless the excavation activities are in compliance with an EPA-approved site management plan. The site management plan would provide for the proper management of all post-construction remedy components. Specifically, the site management plan would describe procedures to confirm that the requisite engineering (subsurface demarcation) and institutional controls are in place and that nothing has occurred that will impair the ability of said controls to protect public health or the environment. The site management plan would also include the identification of any use restrictions on the former tannery property; necessary provisions for the implementation ofthe requirements of the above-noted environmental easement and/or restrictive covenant; and provision for the performance of the OM&M required by the remedy.

It is estimated that it would take 24 months to implement this alternative.

Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use and unlimited exposure, CERCLA requires that the site be

|reviewed at least once every five years. If justified by the review, further remedial actions may be implemented to remove or treat the wastes.

Alternative S-3: Contaminated Soil and Sediment Excavation/Dredging, On-Site Solidification, Placement of Solidified Materials on Former Tannery Property, and Soil Cover

Capital Cost:

Annual OM&M Cost:

Present-Worth Cost:

Construction Time:

$12,608,000

$325,000

$14,212,000

24 months

This alternative is the same as Alternative S-2 except, instead of off-site disposal, the excavated soils and sediments, as well as any recovered sludges, would be chemically stabilized, consolidated in low-lying areas on the former tannery property, and covered with a soil cover. Filling ofthe low-lying areas will be consistent with the Village of West Winfield's redevelopment plan for the site.

.Chemical stabilization immobilizes/fixates the contaminants Fby forming chemical bonds, thus, reducing the solubility or availability of the contaminants to the environment. Bench-

scale tests would be required to determine and optimize the solidification agents.

The loose brick and concrete debris, as well as other concrete remnants located on the former tannery property, would, be consolidated in low-lying areas on the former tannery property. Any contaminated soils and sludges associated with the debris and concrete remnants would be excavated/removed, solidified, and placed in the low-lying areas on the former tannery property.

In addition to placing a soil cover over former tannery property areas where residual soil contamination would remain as described in Alternative S-2, underthis alternative, a two-foot thick soil cover would be placed over the consolidated materials located in the low-lying areas on the former tannery property.

The soil cover that is placed over former tannery property areas would need to meet RCRA Subtile D and 6 NYCRR Part 360 closure requirements.

Before placing the soil cover over the solidified materials and areas where residual soil contamination would remain, a readily-visible and permeable subsurface demarcation delineating the interface between the solidified materials and the soil cover and the native soil and the soil, respectively, would be installed.

Under this alternative, institutional controls in the form of an environmental easement and/or restrictive covenant would be used to restrict future development/use of the former tannery property where treated soils are disposed and to restrict any excavation below the former tannery property's soil cover unless the activities are in compliance with an EPA-approved site management plan.

The site management plan would provide for the proper management of all post-construction remedy components. Specifically, the site management plan would describe procedures to confirm that the requisite engineering (subsurface demarcation) and institutional controls are in place and that nothing has occurred that will impair the ability of said controls to protect public health or the environment. The site management plan would also include the identification of any use restrictions on the former tannery property; necessary provisions for the implementation ofthe requirements of the above-noted environmental easement and/or restrictive covenant; and provision for the performance of the OM&M required by the remedy.

Sampling and analysis of groundwater samples would be performed for an estimated five years to facilitate an evaluation of the effectiveness of the stabilization process.

It is estimated that it would take 24 months to implement this alternative.



Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use

kand unlimited exposure, CERCLA requires that the site be 'reviewed at least once every five years. If justified by the review, further remedial actions may be implemented to remove or treat the wastes.

Groundwater Alternatives

Alternative GW-1: No Action

Capital Cost:

Annual OM&M Cost:

Present-Worth Cost:

Construction Time:

$0

$0

$0

0 months

The Superfund program requires that the "no-action" alternative be considered as a baseline for comparison with the other alternatives. The no-action remedial alternative would not include any physical remedial measures to address the groundwater contamination at the site.

Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use

.and unlimited exposure, CERCLA requires that the site be reviewed at least once every five years. If justified by the review, remedial actions may be implemented to remove or treat the wastes.

Alternative GW-2: Intermittent Groundwater Extraction and Treatment

Capital Cost:

Annual OM&M Cost:

Present-Worth Cost:

Construction Time:

$334,000

$123,000*

$920,000

6 months

Underthis alternative, contaminated groundwater would be extracted utilizing the three monitoring wells in the semi-confining unit where contamination was detected. Since two of the monitoring wells are artesian during the wet season, they should readily support continuous extraction during this season: During dryrseasons, the three wells may be pumped dry. Therefore, pumping would continue as long as

there is sufficient water in the wells and halted when the well level drops below a set level.

As was noted above, the detection of contamination in the semi-confining unit is attributable to suspended colloidal particulates in the samples, as contaminants were only found in the unfiltered, highly turbid samples. Therefore, removal of the suspended solids via filtration (e.g., bag filters) is likely to be the only form of treatment needed. The filtered water would be discharged to the Unadilla River in conformance with SPDES requirements.

Metals contamination on the suspended colloidal particulates appears to be a localized phenomenon, appearing in only three monitoring wells. While suspended colloidal particulates can easily be removed by filtration, the particulates may, however, persist within the aquifer. Therefore, how long it would take to effectively restore groundwater quality is indeterminate. It is anticipated that the groundwater extraction and treatment would be performed for one year. Groundwater monitoring would, however, continue for a longer duration.

It is estimated that it would take six months to construct this alternative.

This alternative would also include long-term monitoring and institutional controls in the form of an environmental easement and/or restrictive covenant that would restrict the use of groundwater in the semi-confining unit as a source of potable or process water unless groundwater quality standards are met.

Under this alternative, a site management plan would be developed to provide for the proper management of all post-construction remedy components, such as institutional controls, and include the identification of any use restrictions on the former tannery property; necessary provisions for the implementation of the requirements of the above-noted environmental easement and/or restrictive covenant; and provision for the performance of the OM&M required by the remedy.

Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use and unlimited exposure, CERCLA requires that the site be reviewed at least once every five years.

Alternative GW-3: Long-Term Groundwater Monitoring and Institutional Controls

The first year O&M cost would consist of $40,000 for groundwater monitoring and $83,000 to operate the groundwater extraction and treatment system. Subsequent years would consist of only groundwater monitoring.


Capital Cost:

Annual OM&M Cost:

Present-Worth Cost:

Construction Time:

1 0 . . 0 0 0 4 9

$35,000

$40,000

$528,000

1 month


•a! Ul

This alternative would also include long-term monitoring and institutional controls in the form of an environmental asement and/or restrictive covenant that would restrict the

use of groundwater in the semi-confining unit as a source of potable or process water unless groundwater quality standards are met.

Under this alternative, a site management plan would be developed to provide for the proper management of all post-construction remedy components, such as institutional controls, and include the identification of any use restrictions on the former tannery property; necessary provisions for the implementation of the requirements of the above-noted environmental easement and/or restrictive covenant; and provision for the performance of the OM&M required by the remedy.

It is estimated that it would take one month to prepare the sampling plan needed to carry out this alternative.

Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use and unlimited exposure, CERCLA requires that the site be reviewed at least once every five years.

COMPARATIVE ANALYSIS OF ALTERNATIVES

During the detailed evaluation of remedial alternatives, each |alternative is assessed against nine evaluation criteria, namely, overall protection of human health and the environment, compliance with applicable or relevant and appropriate requirements, long-term effectiveness and permanence, reduction of toxicity, mobility, or volume through treatment, short-term effectiveness, implementability, cost, and state and community acceptance. The evaluation criteria are described below.

Overall protection of human health and the environment addresses whether or not a remedy provides adequate protection and describes how risks posed through each exposure pathway (based on a reasonable maximum exposure scenario) are eliminated, reduced, or controlled through treatment, engineering controls, or institutional controls.

• Compliance with ARARs addresses whether or not a remedy would meet all of the applicable or relevant and appropriate requirements of other federal and state environmental statutes and requirements or provide grounds for invoking a waiver.

• Long-term effectiveness and permanence refers to the ability of a remedy to maintain reliable protection of human health and the environment over time, once cleanup goals have been met. It also addresses the magnitude and effectiveness of the measures that may be required to manage the risk

posed by treatment residuals and/or untreated wastes.

Reduction of toxicitv. mobility, or volume through treatment is the anticipated performance of the treatment technologies, with respect to these parameters, a remedy may employ.

Short-term effectiveness addresses the period of time needed to achieve protection and any adverse impacts on human health and the environment that may be posed during the construction and implementation period until cleanup goals are achieved.

Implementability is the technical and administrative feasibility of a remedy, including the availability of materials and services needed to implement a particular option.

• Cost includes estimated capital and OM&M costs, and net present-worth costs.

State acceptance indicates if, based on its review of the RI/FS and Proposed Plan, the state concurs with the preferred remedy at the present time.

Communitv acceptance will be assessed in the ROD and refers to the public's general response to the alternatives described in the Proposed Plan and the RI/FS reports.

A comparative analysis of these alternatives based upon the evaluation criteria noted above follows.

Overall Protection of Human Health and the Environment ^

Alterative S-1 would not be protective of human health and the environment, since it would not actively address the contaminated soils and sediments which present unacceptable risks of human and ecological exposure. Alternatives S-2 and S-3, on the other hand, would be protective of human health and the environment, since each alternative relies upon a remedial strategy and/or treatment technology capable of eliminating exposure in combination with institutional controls, engineering controls (subsurface demarcation), and a site management plan. Under these alternatives, the contaminants would either be treated/disposed of off-site (Alternative S-2) or solidified and covered with soil on the former tannery property (Alternative S-3).

Since Alternatives GW-1 and GW-3 would rely upon natural attenuation^ (a process which has not been demonstrated to


Natural attenuation is a variety of/n-s/ftv processes which, under favorable conditions, act without human intervention to reduce the mass, toxicity, mobility, volume, or concentration of contaminants in groundwater.

1 0 . 0 0 0 5 0


Ul

• r tr(

be occurring at the site) to restore groundwater quality to drinking water standards, they would not be as protective as

Iternative GW-2, which would include extraction and reatment of contaminated groundwater. The institutional

controls under Alternatives GW-2 and GW-3 would provide protection of public health until groundwater standards are met.

Compliance with ARARs

There are currently no federal or state promulgated standards for contaminant levels in soils and sediments. There are, however, other federal or state advisories, criteria, or guidance (which are used as TBC criteria). For soils. New York State TAGM objectives are a TBC criteria. For sediments, NYSDEC's sediment screening values are a TBC criteria.

EPA and NYSDOH have promulgated health-based protective MCLs (40 CFR Part 141, and 10 NYCRR, Chapter 1), which are enforceable standards for various drinking water contaminants (chemical-specific ARARs). Although the groundwater at the site is not presently being utilized as a potable water source, achieving MCLs in the groundwater is an applicable standard, because area groundwater is a source of drinking water. Alternatives GW-1 and GW-3 would not provide for any direct remediation of groundwater and would, therefore, rely upon natural processes (which have not been demonstrated to be occurring at the site) to achieve chemical-specific ARARs. Alternative GW-2 would be the most effective in reducing groundwater contaminant concentrations below MCLs, since it would include the collection and treatment of contaminated groundwater.

Long-Term Effectiveness and Permanence

Since the contaminated soils would not be addressed under Alternative S-1, this alternative would not achieve the human health protection values for soils. Since the contaminated sediments would not be addressed under this alternative, it would also not comply with the sediment cleanup objectives.

Under Alternatives S-2 and S-3, excavating the former tannery property soils exceeding the human health protection values and covering soils with residual contamination that exceeds the TAGM objectives would achieve compliance

.with TBCs.

The sediment component of Alternatives S-2 and S-3 would attain sediment cleanup levels for all riverbed areas.

Alternative S-2 would be subject to New York State and federal regulations related to the off-site transportation of wastes. Since the excavated soils and sediments would be transported to the former tannery property area for solidification, Alternative S-3 would also be subject to New York State and federal regulations related to the transportation of wastes.

Since Alternatives S-2 and S-3 would involve the excavation/dredging of contaminated soils and sediments, they would require compliance with fugitive dust regulations.

Since leather waste is defined in the RCRA regulations as a solid waste, but not a hazardous waste, RCRA Subtitle D and 6 NYCRR Part 360 closure requirements would apply to the consolidation of the excavated/dredged soils and sediments in the low-lying area underAlternative S-3.

The provisions of New York State Environmental Conservation Law Section 27-1318, Institutional and Engineering Controls, may be applicable to the environmental easements in Alternatives S-2, S-3, GW-2,

.and GW-3.

Alternative S-1 would involve no active remedial measures and, therefore, would not be effective in eliminating the potential exposure to contaminants in soils and sediments. Both Alternatives S-2 and S-3 would be effective in the long term by removing contaminated soils and sediments that exceed human health protection values and present ecological risks and covering soils with residual contamination, in combination with engineering controls (subsurface demarcation), institutional controls, and a site management plan. Alternatives S-2 and S-3 would both provide permanent remediation by removing the contaminated soils and sediments to an off-site treatment/disposal facility and treating and consolidating them on-site, respectively.

Alternatives GW-1 and GW-3 would be expected to have minihial long-term effectiveness, since they both would rely upon natural attenuation to restore groundwater quality. Natural attenuation has not, however, been proven to be occurring at this site. Alternative GW-2, by actively pumping and treating the contaminated groundwater, would have long-term effectiveness and permanence and achieve groundwater standards at a faster rate than Alternatives GW-1 and GW-3.

Metals contamination on the suspended colloidal particulates appears to be a localized phenomenon, appearing in only three monitoring wells. While Alternative GW-2 would be effective during pumping and suspended colloidal particulates can easily be removed by filtration, the particulates may, however, persist within the aquifer. Therefore, how long it would take to effectively restore groundwater quality is indeterminate. Since limited water is expected to be available in the wells in the semi-confining layer, hydraulic control is not likely to be established during pumping. However, since the suspended colloidal particulates appears to be a localized phenomenon, complete hydraulic control would not be required.



#

Alternative GW-2 would generate treatment residues which would have to be appropriately handled; Alternatives GW-1

nd GW-3 would not generate such residues.

Mobilitv. or Volume Through Reduction in Toxicitv. Treatment

Alternative S-1 would provide no reduction in toxicity, mobility or volume. Under Alternative S-2, the mobility and volume of the contaminants would be eliminated by removing the contaminated soil for off-site treatment/disposal. Under Alternative S-3, the toxicity and mobility of the contaminants would be reduced by on-site treatment (stabilization). However, as a result ofthe stabilization process, the volume would increase.

Alternatives GW-1 and GW-3 would not effectively reduce ' the toxicity, mobility, or volume of contaminants in the groundwater, as these alternatives involve no active remedial measures. These alternatives would rely on natural attenuation to reduce the levels of contaminants; a process that has not been demonstrated to be occurring at this site. Collecting and treating contaminated groundwater under Alternative GW-2, on the other hand, would reduce the toxicity, mobility, and volume of contaminants, thereby satisfying CERCLA's preference for treatment.

Short-Term Effectiveness

m.

#

ince Alternative S-1 does not include any physical construction measures in any areas of contamination it, would not present any potential adverse impacts to workers on the former tannery property or the community as a result of its implementation. Alternatives S-2 and S-3 could present some limited adverse impacts to remediation workers through dermal contact and inhalation related to excavation/dredging activities. Noise from the excavation/dredging work associated with Alternative S-2 and from the excavation/dredging work and stabilization process associated with Alternative S-3 could present some limited adverse impacts to remediation workers and nearby residents. In addition, interim and post-remediation soil sampling activities would pose some risk. The risks to remediation workers and nearby residents under all of the alternatives could, however, be mitigated by following appropriate health and safety protocols, by exercising sound engineering practices, and by utilizing proper protective equipment.

Alternative S-2 would require the off-site transport of contaminated soils and sediments, which may pose the potential for traffic accidents, which in turn could result in releases of hazardous substances. Alternative S-3 would require the transport of contaminated soil and sediments through the Village to the former tannery property for stabilization, which may pose the potential for traffic

ccidents, which in turn could result in releases of hazardous substances. Under Alternatives S-2 and S-3, substantial disturbance ofthe land during excavation activities could

affect the surface water hydrology of the areas being excavated. For these alternatives, there is a potential for increased stormwater runoff and erosion during excavation activities that would have to be properly managed to prevent or minimize any adverse impacts. For these alternatives, appropriate measures would have to be taken during excavation/dredging activities to prevent the transport of fugitive dust.

Under Alternatives S-2 and S-3, there is a potential that the excavation/dredging of contaminated sediments may adversely affect the wetland and river bed. In addition, the excavation/dredging ofcontaminated sediments would likely result in releases of contaminated sediments, which might increase ecological exposures in the short term. Although these alternatives would provide lower residual risks to the environment relative to the no-action alternative, they would disturb wetland habitats. Removing contaminated Unadilla River sediments located adjacent to the former tannery property would likely cause only limited adverse ecological impacts, since only a small segment of the river would be remediated. The remediation of the downstream areas, on the other hand, would likely result in more significant adverse ecological impact since a much larger portion of the river would be remediated (40 CY of contaminated sediments adjacent to the former tannery property as compared to 2,400 CY of contaminated sediments located adjacent to the former tannery property and downstream). Many of the downstream stretches ofthe river are remote and access to the river sediments would require significant tree clearing, and road construction in wetland areas: Wetland restoration issues may persist long after sediment removal activities have ceased.

Since no actions would be performed under Alternative S-1, there would be no implementation time. For Alternatives S-2 and S-3, it is estimated that it would take 24 months to implement.

Alternative GW-1 would have no short-term impact to workers or the community and would have no adverse environmental impacts, since no actions would be taken. Alternatives GW-2 and GW-3 might present some limited risk to remediation workers through dermal contact and inhalation related to groundwater sampling activities. While it is assumed that existing monitoring wells in the semi-confining unit would be used to extract contaminated groundwater underAlternative GW-2, ifadditional wells need to be installed, this alternative would pose an additional risk to on-site workers, since it would involve the installation of extraction wells through potentially contaminated soils and groundwater. The risks to on-site workers could, however, be minimized by utilizing proper protective equipment.

Since no actions would be performed underAlternative GW-1, there would be no implementation time. For Alternative GW-2, it is estimated that it would take six months to implement. For Alternative GW-3, it is estimated that it would take one month to implement.



01

The contamination in the semi-confining unit is attributable to colloidal particulates. Since the mass of colloidal

articulates cannot be determined, time frames to reach groundwater standards under all of the groundwater alternatives is indeterminate.

Implementability

Alternative S-1 would be the easiest to implement, as there are no activities to undertake.

The filtration unit and metal adsorption media technologies that would be used for groundwater treatment are proven and-reliable in achieving the specified performance goals and are readily available.

The implementation of institutional controls would be relatively easy to implement under Alternatives GW-2 and GW-3.

Cost

Solidification (Alternative S-3) is a readily available technology that is proven and reliable in immobilizing metals in soils and sediments. Equipment, services, and materials needed for all ofthe soil and sediment action alternatives are readily available and the actions under these alternatives would be administratively feasible. Sufficient facilities are available for the off-site treatment/disposal of the excavated materials under Alternative S-2.

Under Alternatives S-2 and S-3, determining the extent of the excavation/dredging could be easily accomplished through post-excavation/dredging soil and sediment sampling and analysis.

Monitoring the effectiveness of the solidification process underAlternative S-3 would be easily accomplished through groundwater monitoring.

• ^

m

he excavation/dredging of sediments in the open water located adjacent to the former tannery property area would be fairly easy to implement, since the sediments would be easily accessible. Addressing the sediments in the remote downstream areas, on the other hand, would require significant tree clearing, road construction, erosion control and intrusion in wetland areas. Therefore, it is likely that removing contaminated sediments in the Unadilla River in the remote downstream areas may result in significant environmental impacts.

The implementation of institutional controls, engineering controls (subsurface demarcation), and the development of a site management plan would be relatively easy to implement under Alternatives S-2 and S-3.

Alternative GW-1 would be the easiest to implement, since it would not entail the performance of any activities. Alternative GW-3 would also be easy to irnplement technically with little or no administrative problems.

Equipment, services, and materials needed for all of the groundwater action alternatives are readily available and the actions under these alternatives would be administratively feasible. Groundwater extraction and treatment systems similar to that which would be used under Alternative GW-2 have been implemented successfully at numerous sites to xtract and treat contaminated groundwater.

The present-worth cost associated with the Alternatives S-2 and S-3 is calculated using a discount rate of 7% and a 5-yeartime interval. The present-worth cost associated with the Alternatives GW-2 and GW-3 is calculated using a discount rate of 7% and a 30-year time interval. The estimated capital, operation, maintenance, and monitoring (OM&M), and present-worth costs for each of the alternatives are presented below.

Alternative

S-1

S-2

S-3

GW-1

GW-2

GW-3

Capital

$0

$15,036,000

$12,608,000

$0

$334,000

$35,000

Annual OM&M

$0

$310,000

$325,000

$0

$123,000^°

$40,000

Total Present-

Worth

$0

$16,129,000

$14,212,000

$0

$920,000

$528,000

As can be seen by the cost estimates, Alterative S-1 is the least costly soil/sediment alternative at $0. Alterative S-2 is the most costly soil alternative at an estimated present-worth cost of $16,129,000. The least costly groundwater remedy is Alternative GW-1 at $0. Alternative GW-2 is the most costly groundwater alternative at an estimated present-worth cost of $920,000.

State Acceptance

NYSDEC concurs with the preferred soil/sediment and groundwater alternatives.

10


The first year O&M cost would consist of $40,000 for groundwater monitoring and $83,000 to operate the groundwater extraction and treatment system. Subsequent years would consist of only groundwater monitoring.

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Communitv Acceptance "

^Community acceptance of the preferred alternative will be 'assessed in the ROD following review of the public comments received on the Proposed Plan.

PROPOSED REMEDY

Based upon an evaluation of the various alternatives, EPA, in consultation with NYSDEC, recommends Alternative S-3 (contaminated soil and sediment excavation/dredging, on-site solidification and consolidation on the former tannery property, and soil cover) and Alternative GW-2 (intermittent groundwater extraction and treatment) as the preferred remedy for soil and groundwater, respectively. Specifically, this would involve the following:

Excavation of soil from three former tannery property hot spots that exceed human health protection values (Areas S I , S2, and S3) (see Table 1 and Figure 2). The two surface soil hot spots (Areas SI and S3) would be excavated to a depth of 2 feet and the subsurface soil hot spot (Area S2) would be excavated to a depth of approximately 4 feet. The sluiceway would be excavated in conjunction with Area S3.

Excavation of a surficial soil hot spot located to the east of Area SI (Area S8), soil from unsaturated zone soil hot spots^^ underlying Areas SI and S3, unsaturated zone soil hot spots underlying Area S2, an unsaturated zone soil hot spot located in the southeastern corner of the foundation remnants (Area S4), and unsaturated zone soil hot spots located in the former lagoons (Area S5).

An approximately 800-foot long, 20-foot wide contaminated strip along the top of the northern bank of the river would be excavated to a depth of 2 feet (Area S6). In addition, contaminated soil along the 225-foot unriprapped portion of the side of the northern riverbank would be excavated 5 feet laterally from the edge of the river (Area S7).

Contaminated wetland sediments would be excavated to a depth of 3 feet. Post-excavatiort samples would be collected.

During the design phase, Unadilla River sediment background concentrations would be reassessed.

Unsaturated zone soil hot spots are defined as grossly-contaminated soil/material. To the extent practicable, excavation (and associated on-site solidification) would occur during a low groundwater table period (;.e., July -November) with a goal of removing the hot spots to a depth of 6 -7 feet or the groundwater table, whichever is deeper.


Contaminated Unadilla River sediments located adjacent to the former tannery property exceeding the sediment screening values (LELs, see Table 2, above) or sediment background concentrations, if appropriate, would be excavated/dredged. Since contaminated sediments would be left in place downstream of the former tannery property, following baseline sediment and biological sampling, short- and long-term monitoring in these areas would be performed. Short-term monitoring would be performed on an annual basis for a period of five years. Long-term monitoring would be performed every five years after the short-term monitoring ceases. The baseline, short-, and long-term monitoring would include sediment chemical analyses, sediment toxicity testing, and analysis of benthic macro invertebrate communities. The need for remediation in areas further downstream of the former tannery property would be evaluated based on an assessment ofthe above-noted sediment and biological analyses. Further remediation would be required in the downstream areas if it is determined through monitoring that the remedial activities that were conducted upstream in the river, in the wetland, and on the former tannery property were not effective in eliminating the ecological risk.

The loose brick and concrete debris, as well as other concrete remnants (including the demolition and removal ofthe dye tanks) located on the former tannery property and the demolition and removal of the foundation remnants (if consistent with the Village of West Winfield's redevelopment plan for the site), would be consolidated in low-lying areas on the former tannery property. Any contaminated soils and sludges associated with the debris and concrete remnants would be excavated/removed. Filling of the low-lying areas will be consistent with the Village of West Winfield's redevelopment plan for the site.

All excavated sediments would be dewatered, as necessary. Excavated/dredges soils, sediments, and sludges would be chemically stabilized and consolidated in low-lying areas on the former tannery property.

A two-foot thick soil cover would be placed over the consolidated materials in the low-lying areas on the former tannery property. In former tannery property areas where residual soil contamination exceeds the TAGM objectives, a soil cover with a thickness of two feet would be placed in areas with "active" exposure potential (e.g., playing fields) and a thickness of one-foot thick in areas with "passive" exposure potential (e.g., walking trails, parking lots). "Active" and "passive" areas are based on the current future-use plan prepared by the Village of West Winfield.

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Before placing the soil cover over the solidified materials and areas where residual soil contamination would remain, a readily-visible and permeable subsurface demarcation delineating the interface between the solidified materials and the soil cover and the native soil and the soil, respectively, would be installed.

The excavated areas would be backfilled with clean soil. With the exception of the riverbank, the backfilled areas, as well as the soil cover, would be seeded with grass to stabilize the soil. The riverbank would be restored with appropriate vegetation. Inspections of the restored riverbank would be performed for several years to ensure adequate survival of the planted vegetation. Replanting would be performed, if necessary.

The disturbed remediated wetlands and river bed would be restored. All remedial work in these areas would comply with the substantive requirements of New York State Environmental Conservation Law Articles 15 and 24, 6 NYCRR Parts 608 and 663; Executive Order 11990,40 CFR Part 6 Appendix A, "Statement of Procedures on Floodplains Management & Wetlands Protection"; and Section 404 of the Clean Water Act. The restored wetlands would require routine inspection for several years to ensure adequate survival of the planted vegetation. Replanting would be performed, if necessary. Short- and long-term monitoring of wetland sediments would be performed to evaluate the effectiveness of the remedy. Further remediation would be required in the wetland if it is determined through monitoring that recontamination from underlying sediments has occurred.

Contaminated groundwater would be extracted on an intermittent basis from three existing monitoring wells in the semi-confining unit.

Water generated from dewatering the sediments and from runoff would be collected. This water would be treated at an on-site facility by methods appropriate for the treatment of metals, such as a filtration and metal adsorption media. The extracted groundwater would be treated by filtration. All treated water would be discharged to the Unadilla River in conformance with SPDES requirements.

Short-term groundwater monitoring (estimated five years) to evaluate the effectiveness of the stabilization process.

Long-term groundwater monitoring.

Imposition of institutional controls in the form of an environmental easement and/or restrictive covenant that would, at a minimum, require: (a) restricting future development/use of the former tannery


property where treated soils are located and restricting any excavation below the former tannery property's soil cover unless the activities are in compliance with an EPA-approved site management plan (see below); (b) restricting the use of groundwater in the semi-confining unit as a source of potable or process water unless groundwater quality standards are met; and (c) the owner to complete and submit periodic certifications that the institutional controls are in place.

Development of a site management plan. The site management plan would provide for the proper management of all post-construction remedy components. Specifically, the site management plan would describe procedures to confirm that the requisite engineering (subsurface demarcation) and institutional controls are in place and that nothing has occurred that will impair the ability of said controls to protect public health or the environment. The site management plan would also include the identification of any use restrictions on the former tannery property; necessary provisions for the implementation ofthe requirements ofthe above-noted environmental easement and/or restrictive covenant; and provision for the performance of the OM&M required by the remedy.

Periodic reviews by EPA to ensure that the remedy continues to be protective of public health and the environment.

The boundaries of the soil excavations will be defined in a remedial design sampling program.

Because this alternative would result in contaminants remaining on-site above levels that allow for unrestricted use and unlimited exposure, CERCLA requires that the site be reviewed at least once every five years. If justified by the review, further remedial actions may be implemented to remove or treat the wastes.,

Basis for the Remedy Preference

Under Alternatives S-2 and S-3, the excavation/dredging of sediments in the open water located adjacent to the former tannery property area would be fairly easy to implement, since the sediments would be easily accessible. Addressing the sediments in the remote downstream areas, on the other hand, would require significant tree clearing, road construction, erosion control and intrusion in wetland areas. In addition, significant adverse ecological impacts would likely occur in the downstream areas, since a much larger portion of the river would be remediated. As a result, addressing all ofthe contaminated sediments in the Unadilla River would present potentially significantly greater environmental impacts than just addressing the contaminated sediments located adjacent to the former tannery property.

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Through solidification. Alternative S-3 would satisfy CERCLA's preference for remedial actions which employ, as

ka principal element, treatment to permanently and "significantly reduce the volume, toxicity, or mobility of the hazardous substances, pollutants and contaminants at a site (although the volume would increase).

While Alternatives S-2 and S-3 would both effectively achieve the soil cleanup levels and provide the same degree of protection of human and ecological receptors, off-site disposal under Alternative S-2 would be more costly than on-site solidification under Alternative S-3. Therefore, EPA believes that Alternative S-3 would effectuate the soil cleanup while providing the best balance of tradeoffs with respect to the evaluating criteria.

Alternatives GW-1 and GW-3 would rely upon natural processes (which have not been demonstrated to be occurring at the site) to restore groundwater quality to drinking water standards. Although more costly than the other action alternative. Alternative GW-2, which would include extraction and treatment of contaminated groundwater, would likely result in the restoration of water quality in the aquifer more quickly than natural processes. Therefore, EPA has identified Alternative GW-2 as its preferred groundwater alternative, since it would effectuate the groundwater cleanup while providing the best balance of tradeoffs among the alternatives with respect to the evaluation criteria.

)T\r\e preferred remedy is believed to provide the greatest protection of human health and the environment, provide the greatest long-term effectiveness, be able to achieve the ARARs more quickly, or as quickly, as the other alternatives, and is cost-effective. Therefore, the preferred remedy would provide the best balance of tradeoffs among alternatives with respect to the evaluation criteria. EPA and NYSDEC believe that the preferred remedy would treat principal threats, be protective of human health and the environment, comply with ARARs, be cost-effective, and utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable. The preferred remedy also would meet the statutory preference for the use of treatment as a principal element.


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• ^ Remediation Wells

Water Body Boundary

^ ^ ^ • ^ ~ Site Boundary

i

F^~77 - •?i Treated Soil and Sediment L_ i£™i i j Placement Area

^

) . _ . .

Excavation Limits

Soil Cover Areas Note: Soil cover areas in which soil contaminant levels exceed the TAGM objectives. Areas with "active" exposure (e.g., playing fields) will be covered with two feet of soil. Areas with "passive" exposure potential (e.g., walking trails, parking lots) will be covered with one foot of soil. "Active" and "passive" areas are based on the cun-ent future-use plan for the Village of West Winfield.

NOTE: 1) Area S6 includes excavation along the top of the river bank. The excavation does not include rip-rap or other river bank stabilization stnjctures.

2) Area URI excavation includes river bottom sediment only. The excavation does not include rip-rap or other river bank stabilization structures.

3) Area S7 (river's edge with no rip-rap) is not shown on this figure due to scaling. Area 87 has an area of 1,125 square feet and depth of 5 feet.

CDM Figure 2

Locations of On-Property Soil and Sediment Excavation Areas, Treated Soil and Sediment Placement Area, Soil Cover Areas, and Groundwater Remediation Wells

Hiteman Leather Company Superfund Site West Winfield, New York

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hiteman b f uo

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