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Superfund ProgramShaffer Landfill Iron Horse ParBillerica MA

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Supplement Proposed Plan

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May 1991

EPA Issues Supplement to Proposed Plan for Cleanup of the Shaffer Landfill Iron Horse Park Superfund Site

The US Environmental Protection Agency (EPA) is issuing a Supplement to the Proposed Plan in which it is proposing an alternate cleanup plan referred to as the Preferred Alternative to address contamination at the Shaffer Landfill Iron Horse Park Superfund Site in Billerica MA

The Supplement to the Proposed Plan describes a cleanup option developed and recommended from among those that were evaluated during the Remedial Investigation (RI) and Feasibility Study (FS) performed for the site and which were commented on extensively by the public These comments were received during the 60-day comment period for the original Proposed Plan Although this Preferred Alternative is a significant change from the earlier Preferred Alternative EPA believes this change could be reasonably anticipated by the public based upon the other alternatives discussed For this reason the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) does not require additional public participation However because EPA is interested in the publics views on the new Preferred Alternative EPA is providing an opportunity for public to review and comment The other alternatives discussed in this Supplement to the Proposed Plan are identical to those which appeared in the original Proposed Plan of January 15 1991 This Supplement to the Proposed Plan also discusses impacts on floodplains by remedial alternatives considered by EPA EPA will consider public comments made on this Supplement to the Proposed Plan as part of the final decision-making process for selecting the cleanup remedy for the site

The Preferred Alternative now includes 1) reconstruction of the entire landfill cap and 2) collection and treatment of leachate to remove and prevent further migration of contaminants The Preferred Alternative is described in greater detail on pages 9 and 10 of this document

This Supplement to the Proposed Plan 1 explains the opportunities for the public to comment on

the remedial alternatives 2 includes a brief history of the site and the

principal findings of site investigations

Mote Words that appear in bold print in this docunent are defined in the glossary on pages 19 and 20

3 provides a brief description of the Preferred Alternative and other alternatives evaluated in the FS

4 outlines the criteria used by EPA to propose an alternative for use at the site and briefly analyzes whether the alternatives meet each criteria and

5 presents EPAs rationale for its preliminary selection of the preferred alternative

To help the public participate in reviewing the cleanup options for the Landfill this document also includes information about where interested citizens can find more detailed descriptions of the remedial process and the alternatives under consideration for the Shaffer Landfill section of the Iron Horse Park Site

THE PUBLICS pOfrF TN EVALUATING REMEDIAL ALTERNATIVES

PUBLIC INFORMATIONAL MEETING

On January 15 1991 EPA held a public informational meeting at 730 pm in the Billerica Town Hall to describe the Proposed Plan and other alternatives evaluated in the Feasibility Study (FS) Following the presentations EPA held a question and answer period

PUBLIC COMMENT PERIOD ON PROPOSED PLAN

EPA conducted a 60 day-public comment period from January 16 to March 16 1991 to provide an opportunity for public input on the agencys Proposed Cleanup Plan and Feasibility Study

PUBLIC COMMENT PERIOD ON SUPPLEMENT TO THE PROPOSED PLAN

EPA is conducting a 30-day public comment period from May 18 to June 17 1991 to provide an opportunity for public input on the Supplement to the Proposed Plan During the comment period the public is invited to review the Supplement to the Proposed Plan and offer comments to EPA

INFORMAL PUBLIC HEARINGS

EPA conducted two informal public hearings on February 5 and February 19 1991 at the Billerica Town Hall beginning at 730 pm to accept oral comments on the cleanup alternatives considered for the Site The public hearings provided the public with opportunities to comment on the cleanup plan after they had heard the presentation at the public informational meeting and reviewed the Proposed Plan Comments made at the public hearings have been transcribed and a copy of the transcript will be added to the Site Administrative Record available at the EPA Records Center at 90 Canal Street in Boston Massachusetts and at the information repository listed on page 3

2 Shaffer LandfillSupplement to the Proposed Plan

WRITTEN COMMENTS

If after reviewing the Supplement to the Proposed Plan you would like to comment in writing on it EPAs Proposed Plan or any of the other cleanup alternatives under consideration for this Site please mail your written comments (postmarked no later than June 17 1991) to

Don McElroy Remedial Project Manager US Environmental Protection Agency Waste Management Division (HEC-CAN6) JFK Federal Building Boston MA 02203 (617) 223-5571

EPAS REVIEW OF PUBLIC COMMENT

EPA will review comments received from the public as part of the process of reaching a final decision on the most appropriate remedial alternative for cleanup of the Shaffer Landfill Iron Horse Park Site EPAs final selection of a remedy will be issued in a document called a Record of Decision (ROD) for the Site this summer Accompanying the ROD will be a document called the Responsiveness Summary which summarizes EPAs responses to comments received during both the 60-day public comment period for the Proposed Plan as well as the 30-day public comment period for the Supplement to the Proposed Plan Once the ROD is signed by EPAs Regional Administrator it will become part of the Administrative Record The Administrative Record contains documents used by EPA to reach a final cleanup decision

Additional Public Information

Because this Proposed Plan provides only a summary description of the investigation of the Shaffer Landfill Iron Horse Park Site and the cleanup alternatives considered the public is encouraged to consult the Administrative Record which contains the Remedial Investigation and Feasibility Study (RIFS) reports and other Site documents for a more detailed explanation of the Site and all of the remedial alternatives under consideration

The Administrative Record is available for review at the following locations

EPA Records Center 90 Canal Street 1st Floor Boston Massachusetts 02114 (617) 573-5729 Hours Monday-Friday 830 am to 100 pm and 200 pm

to 500 pm

Billerica Public Library 25 Concord Road Billerica MA 01821 (508) 671-0949 Hours Monday-Thursday 900 am to 900 pm Friday-Saturday 900 am to 500 pm


Site History

The Shaffer Landfill comprises just one part of the Iron Horse Park Superfund Site The entire Site consists of approximately 553 acres of land in North Billerica near the Tewksbury town line (Figure 1) The Site is an active industrial complex and railyard with a long history of activities that have resulted in contamination of soils groundwater and surface water

The Shaffer Landfill is located on property originally owned by the Boston amp Maine Corporation In 1966 the Boston amp Maine Corporation sold the Landfill to the Shaffer Realty Corporation Title to the property was then transferred to the Graypond Realty Trust Graypond Realty Trust is the current owner of the Landfill

The Landfill occupies approximately 106 acres east of Pond Street and south of Richardson Pond in the Town of Billerica MA (see Figure 2) Approximately 60 acres of the property were used for disposal of residential and commercial solid waste over a period of more than 30 years Prior to its use as a landfill the area was a wetland

The Shaffer Landfill itself is divided into two physically distinct sections The western section includes approximately 24 acres and is referred to as the Residential Section The eastern section includes approximately 36 acres and is referred to as the Commercial Section

Records from the Commonwealth of Massachusetts and the Town of Billerica indicate that the property was used for rubbish disposal by 1946 and was an open burning dump for over 20 years In 1968 the Town of Billerica passed new regulations which required that all refuse be placed above the water table that the dump be operated as a sanitary landfill and open burning be stopped The Landfill however generally did not meet the requirements of these regulations open burning continued and daily cover was inadequate

After issuing a series of violation notices and administrative orders citing continued noncompliance with the Commonwealths environmental regulations the Massachusetts Department of Environmental Quality Engineering (now called the Massachusetts Department of Environmental Protection or MA DEP) filed suit in an attempt to obtain compliance with these requirements A settlement was reached by the parties in 1984 The terms of this settlement are contained in a Final Judgment As part of this settlement the Shaffer Landfill ceased accepting refuse at the Commercial Section in 1984 and at the Residential Section in 1986 Work to close the Landfill in accordance with the Final Judgment has been continuing since that time

Iron Horse Park was placed on the National Priorities List (NPL) in September 1984

Cleanup Activities to Date

In August 1984 EPA using its removal authority covered a portion of the Site west of Pond Street known as the Johns-Manville Asbestos Landfill with gravel and topsoil to prevent asbestos in the landfill from becoming airborne


In 1985 EPA began evaluations of the Site to determine the nature and extent of contamination at Iron Horse Park Under the first phase of the evaluation EPA conducted a broad study of the Site This study was entitled the Phase 1A Remedial Investigation (RI) and was conducted from September 1985 to July 1987 As a result of the Phase 1A RI EPA concluded that the size and complexity of the Iron Horse Park Site warranted dividing the Site into Operable Units The Operable Units would then be studied and cleaned up in phases

A Phase IB RI and FS were conducted for Operable Unit 1 the B amp M Wastewater Lagoons A Record of Decision (ROD) choosing a remedy for Operable Unit 1 was signed in September 1988 Work on the remedy for this portion of the Site is currently underway

The Shaffer Landfill is the second Operable Unit The Phase 1C RI was completed in November 1989 The Phase 1C FS was completed in January 1991 Under the Final Judgment entered into with Massachusetts the owners of the Landfill have commenced construction of a cap This cap does not meet the technical specifications of the Final Judgment

The third Operable Unit contains the other areas of concern at Iron Horse Park which were identified in the Phase 1A RI (see section 102 of that document for details) These areas will be addressed in a supplemental RI The characterization of these areas will begin later this year

Results of the Remedial Investigation (RI) The RI identifies the nature and extent of contamination at

the Site EPA conducted field activities for the RI that included the collection and analysis of samples of groundwater sediment and surface water The results of these analyses identified contaminants such as Volatile Organic Compounds (VOCs) acidbaseneutral (ABN) compounds and metals in groundwater sediments and surface water The findings of the field activities are summarized below

1 Groundwater Groundwater flows in three directions around Shaffer Landfill West and southwest of the Landfill groundwater flows north toward Richardson Pond In the central portion of the Landfill groundwater flow is both north toward Richardson Pond and south toward the Middlesex Canal In the eastern portion of the Landfill groundwater flows to the east As part of the process of reaching these conclusions on flow EPA installed 12 new wells and used 37 existing wells in its study of groundwater

The highest levels of VOCs in groundwater were detected east (downgradient) of the Landfill EPA found that VOCs such as benzene xylenes and others are present in this groundwater at levels that are above Maximum contaminant Levels (MCLs) for drinking water Acidbaseneutral (ABN) compounds were detected at low levels in some wells southeast (downgradient) of the Landfill Metals were detected at levels above MCLs in groundwater north (upgradient) of the Landfill and south of the Middlesex Canal

The RI groundwater data suggests that leachate is contaminating groundwater and flowing offsite to the east and southeast

2 Sediment Sediment samples were taken in 33 locations surrounding and adjacent to the Landfill The highest concentrations of VOCs were found north of the Landfill on the


southern edge of Richardson Pond ABN compounds were found both upstream and downstream of the Landfill The highest levels of ABN compounds were found west of the Landfill at relatively low levels and do not appear to have a connection with the Landfill

3 Surface Water EPA collected surface water samples from 19 locations VOCs were found north of the Landfill on the southern edge of Richardson Pond and along Content Brook east and downstream of the Landfill All Ambient Water Quality Criteria (AWQC) for arsenic were exceeded both upstream and downstream of the Landfill but again the highest concentration was measured downstream The AWQC for nickel was exceeded downstream of the Landfill

Summary of Site Risks

An Endangerment Assessment was prepared in 1989 for the Shaffer Landfill The Endangerment Assessment determines the present and future potential risks to public health and the environment posed by the site based on existing conditions as determined by the RI EPA concluded in the Endangerment Assessment that drinking groundwater contaminated by leachate from the Landfill poses a potential risk to human health EPA believes that groundwater in the area around the Landfill is not currently being used for drinking water This means that nobody is currently exposed to this risk If in the future residents were to use the on-site groundwater as a drinking water supply such use could pose unacceptable risks to human health The risk through skin contact with contaminated sediments in the streams is very low

Air quality studies by MADEPs Office of Research and Standards have indicated that while Allowable Ambient Levels (AALs) for certain air pollutants have been exceeded on-site there is no indication that residents off-site are exposed to those higher concentrations

For an explanation of risks posed by contamination at the Shaffer Landfill Site please refer to the Endangerment Assessment presented in Section 60 of the Shaffer Landfill RI report that is available at the information repository at the Billerica Public Library

Proposed Cleanup Objectives

Using the information gathered during the RI and FS EPA identified remedial response objectives for cleanup of the Shaffer Landfill Site The cleanup objectives are listed below

1 Prevent ingestiondirect contact with landfill waste contamination

2 Prevent migration of contamination via leachate which would result in groundwater concentrations in excess of federal MCLs and Massachusetts Groundwater Quality Standards

3 Prevent migration of contamination via leachate to surface waters and sediments to ensure that AWQCs are not exceeded due to the site

4 Prevent damage and loss of wetlands caused by eroding soil from the landfill cap and meet all federal and state wetlands protection ARARs


5 Prevent ingestion of water having contamination in excess of federal MCLs and Massachusetts Groundwater Quality Standards and

6 Restore groundwater aquifer offsite (beyond the boundary of the waste management unit) to contaminant concentrations below federal MCLs and Massachusetts Groundwater Quality Standards

The principle threats at the Landfill stem from groundwater contamination which is a result of leachate migration from the Landfill Groundwater beyond the boundary of the waste management unit will meet MCLs and Massachusetts Groundwater Quality Standards following capping and leachate collection which will result in attenuation of groundwater contamination over time Although exceedances of AWQC have been detected in surface waters this operable unit addresses the Landfill leachate and groundwater only Surface waters will be looked at in the future to see if Superfund is the appropriate mechanism to deal with this problem

Finally it should be noted that the Preferred Alternative for the Landfill does not meet the closure requirements of the Resource Conservation and Recovery Act (RCRA) Subtitle C RCRA Subtitle C closure is not identified as an Applicable or Relevant and Appropriate Requirement (ARAR) for the Landfill because there is no evidence that hazardous waste was disposed of at the Landfill If information becomes available that shows that hazardous waste was disposed of at the Landfill closure of the Landfill under Subtitle C standards may not be possible because it would necessitate covering a portion of the Boston and Maine Railroad tracks and filling a portion of the wetlands EPA seeks your comments on a potential waiver of ARARs pursuant to Section 121 (d)(4) of CERCLA

Floodplains Assessment

Federal policy with respect to floodplain management is codified in 40 CFR Part 6 Appendix A consistent with Executive Order 11988 on floodplain management These regulations require that actions affecting floodplains avoid whenever possible the long and short term impacts associated with the occupancy and modification of floodplains In defining the policy the regulations indicate that when there is no practical alternative to locating in a floodplain the proposed activity must minimize the impact which floods may have on human safety health and welfare as well as the natural environment

During the Phase 1C RI a study of the areas adjacent to the Shaffer Landfill identified the general boundaries of the 100-year floodplain The bulk of the land to the east of the Commercial Section of the Landfill and between the B amp M railroad tracks and the Middlesex Canal is within the 100-year floodplain The exception is a small area approximately 100 feet east of the toe of the Commercial Section This area which is a high point (above the 100-year floodplain) is approximately 400 feet east to west by 500 feet north to south The floodplain area to the east of the Landfill is connected with two other relatively large floodplain areas at the Landfill an area bordered roughly by the Commercial and Residential Sections and the Middlesex Canal and an area which extends south of the Commercial Section of the Landfill and south past the Middlesex Canal The area west of the Landfill to Pond Street is above the


level of the 100-year floodplain (see Figure 3) The remedial alternatives which were evaluated and are

presented in the following section of this Supplement to the Proposed Plan fall into three general categories with respect to potential impact to the 100-year floodplain

The first category is for alternatives which contain no action in and therefore have no impact on the floodplain Alternatives l 2 and 5 fall into this category

The second category is for alternatives which have leachate collection and storage only as a part of the remedy Alternatives 3 4 and the Preferred Alternative fall into this category These alternatives all propose collection of leachate via gravity Of necessity this leads to a collection vessel (tank) located within the floodplain (which is immediately off of the toe of the Landfill This tank could be buried (at present a tank with a 7500 gallon capacity or 10 ft x 10 ft x 10 ft is estimated to be adequate for 3 days of collection capacity) with minimal short-term and virtually no long-term impacts on the floodplain Additionally historical topographic profiles could easily be reproduced An added benefit of this configuration is that the collection system is passive It cannot overflow as the collection would cease if the tank was full This siting method which is the approach that EPA feels is best suited to the Shaffer Landfill involves the least impact or potential impact to the 100-year floodplain of any examined for the collectionstorage of leachate

The third category is for alternatives which require an on-site treatment plant for contaminated groundwater and leachate Alternatives 3A 4A and 5A fall under this category Implementation of these alternatives would also involve construction within the floodplain As a part of these alternatives extraction wells would be located east of the Landfill but west of Content Brook and the contaminated groundwaterleachate would be pumped to the treatment plant Unless located on the relatively high area discussed above these wells would of necessity be located in the floodplain The treatment plant or the majority of it could be located within the higher ground area outside the floodplain In addition collected leachate would need to be delivered to the treatment plant This could be accomplished by a storage tank and piping located within the floodplain or with piping only directly feeding leachate to the treatment plant In either case construction would be required within the floodplain and any permanent structures would need to comply with RCRA floodplain siting requirements Therefore the impact to the floodplain from these alternatives would be from the construction of extraction wells piping and possibly a storage vessel within the floodplain

Floodplain Assessment Finding

EPAs Preferred Alternative falls under the second category of floodplain impact discussed above EPA finds that there is no practical alternative to the scenario presented above of a passive leachate collection system delivering leachate to a storage tank buried within the 100-year floodplain This siting method will have a limited short-term impact on the floodplain Pre-construction grades and topography could easily be restored and there would be a minimum net loss of floodplain There is no floodplain impact under the category 1 alternatives However


Alternatives 1 and 2 do not meet the criterion for Long-term effectiveness and permanence and Alternative 5 does not meet the criterion for ARARs These criteria which are both a part of the alternative evaluation process are discussed below While the siting methods related to category 3 are technically feasible to construct they each introduce issues (greater disturbance to or net loss of floodplain) which make them technically more difficult to implement

EPAa Preferred Alternative

EPAs selection of the preferred cleanup alternative for the Shaffer Landfill Site as described in this Supplement to the Proposed Plan is the result of a comprehensive evaluation and screening process The FS for the Landfill was conducted to identify and analyze the alternatives considered for addressing contamination at the Landfill The FS report for the Shaffer Landfill describes the alternatives considered as well as the process and criteria EPA used to narrow the list to eight potential remedial alternatives (For details on EPAs screening methodology see Sections 3 and 4 of the FS) The following sections describe the Preferred Alternative and the other alternatives EPA retained for detailed analysis

EPA is proposing a cleanup plan to address the source of contamination at the Landfill as well as the resultant groundwater contamination The FS evaluates alternatives which address both Source Control [SW] and Management of Migration [GW])

Source Control EPAs Preferred Alternative for Shaffer Landfill consists of

improvements to the landfill cap and collection removal treatment and disposal of leachate

This alternative would control the sources of contamination by

Reconstruction of the entire Landfill cap This will improve its overall stability and its ability to prevent precipitation from leaching through the Landfill Reconstruction would be achieved by removing the existing topsoil layer adding additional low-permeability soil to 1) provide a 5 grade on the top of the Landfill lobes and 2) provide a consistent smooth sub-grade on the Landfill side slopes installing an impermeable textured membrane liner over the entire Landfill area installing a 6-inch drainage layer installing a non-woven filter fabric between the drainage and topsoil layers reinstalling the topsoil layer to a depth of 12-inches and reseeding the disturbed areas Construction of necessary surface water drainage system Maintenance of cap surface drainage system and landfill gas collectionflare system If necessary improvements will be made Monitoring of gas collectionflare system Construction operation and maintenance of leachate collection facilities Off-site treatment and disposal of leachate Construction of a site perimeter security fence


Management of Contaminant Migration The Preferred Alternative would manage the migration of

contaminants by

- Monitoring of groundwater and surface water quality

Under this alternative the permeability of the Landfill cap is significantly reduced over its entire surface Additionally improvements in adding slope to the top flatter areas and the construction of a drainage layer will greatly improve the removal of surface water from the cap thereby further reducing infiltration through the Landfill and the production of leachate Leachate that is produced would be collected into a leachate storage tank for treatment and disposal off-site in accordance with applicable requirements Groundwater and surface water quality would be monitored to show the effectiveness of these measures in controlling the spread of further contamination and meeting clean up standards

Estimated Time for Design and Construction 2 Years Estimated Time for Operation 30 Years Estimated Capital Cost $9012098 Estimated Operation and Maintenance Cost S3541426 Estimated Total Cost $12553524

Other Alternatives Evaluated in the F8

The public is invited to comment not only on the preferred cleanup alternative but also on the other eight remedial alternatives that EPA evaluated in detail Each of these alternatives is described briefly below A more detailed description of each alternative can be found in the Feasibility Study report THE FOLLOWING ALTERNATIVES APPEARED IN THE PROPOSED PLAN ISSUED IN JANUARY 1991

Alternative l No Action This alternative was evaluated in detail in the FS to serve as a baseline for comparison with the other remedial alternatives under consideration Under this alternative no treatment or containment of waste or leachate would occur and no effort would be made to restrict potential exposure to site contaminants

Alternative 2 Landfill Cap CompletionRepair Alternative 2 consists of improvements to the top flatter portions of the existing Landfill cap Alternative 2 would include

- Repair of top portions (approximately 16 acres) of existing cap on both sections of the Landfill by addition of fill and regrading to achieve minimum 5 slopes followed by reconstruction of the low permeability and topsoil layers over those areas - Maintenance of cap surface drainage system and landfill gas collectionflare system If necessary improvements will be made - Monitoring of gas collectionflare system - Monitoring of groundwater and surface water quality and - Construction of a site perimeter fence


Estimated Time for Design and Construction 6 months Estimated Period for Operation 30 years Estimated Capital Cost $1330000 Estimated Operation and Maintenance (net present worths $901000 Estimated Total Cost (net present worth) $2231000

Alternative 3 Landfill Cap CompletionRepair with Leachata Collection Alternative 3 contains the same features as Alternative 2 in terms of completion and maintenance of the landfill cap In addition Alternative 3 calls for

- Improvements to the existing surface drainage system - Construction operation and maintenance of leachate collection facilities and - Off-site treatment and disposal of leachate

Estimated Time for Design and Construction 1 year Estimated Period for Operation 30 years Estimated Capital Cost $1649000 Estimated Operation and Maintenance Cost (net present worths $3541000 Estimated Total Cost (net present worth1 $5190000

Alternative 3At Landfill Cap CompletionRepair with Leachate Collection and Qroundwater Extraction and Treatment Alternative 3A contains the same features as Alternative 3 in terms of completion and maintenance of the landfill cap improvements to the surface drainage system and leachate collection and treatment In addition Alternative 3A calls for

- Construction operation and maintenance of a groundwater extraction system along the eastern side of the landfill - Construction operation and maintenance of an on-site system for treatment of groundwater and leachate and - Discharge of treated groundwater to surface water

Estimated Time for Design and Construction 2 years Estimated Period for Operation 30 years Estimated Capital Cost $8842000 Estimated Operation and Maintenance Cost (net present worth) $4310000 Estimated Total Cost (net present worth) $13152000

Alternative 4 Partial Reconstruction of Landfill Cap with Leachate Collection Alternative 4 is similar to EPAs Preferred Alternative in terms of the type of cap reconstruction However the scope of the reconstruction is limited to the top flatter portions of the Landfill Alternative 4 calls for

- Reconstruction of the top portions (approximately 16 acres) of the existing landfill cap by removing the existing topsoil layer adding fill and regrading to achieve a minimum 5 slope installing additional low permeability material (either an additional 12-inches of soil with a maximum permeability of 1x10-7 cmsec or a geo membrane) installing a new 6-inch drainage layer reinstalling the topsoil layer to a revised depth of 12-inches and reseeding the disturbed areas - Improvements to the existing surface drainage system - Maintenance of cap surface drainage system and landfill


gas collectionflare system If necessary improvements will be made - Construction operation and maintenance of leachate collection facilities and - Off-site treatment and disposal of leachate

Estimated Time for Design and Construction 1 year Estimated Time for Operation 30 years Estimated Capital Cost $2095000 Estimated Operation and Maintenance Cost fnet present worth) S3541OOP Estimated Total Cost (net present worth) $5637000

Alternative 4A Partial Reconstruction cf Landfill Cap with Leachate collection and Groundvater Extraction and Treatment Alternative 4A contains the same features as Alternative 4 in terms of completion and maintenance of the Landfill cap In addition Alternative 4A also includes


Estimated Time for Design and Construction 2 years Estimated Period for Operation 30 years Estimated Capital Cost S9257OOP Estimated Operation and Maintenance Cost fnet present worth) $4310000 Estimated Total Cost fnet present worth) $13567000

Alternative 5 Total Reconstruction of Landfill Cap This alternative involves a complete reconstruction of the Landfill cap but does not include leachate collection and treatment The components of Alternative 5 are

- Reconstruction of the entire landfill cap to meet EPAs recommended final cover design standards for hazardous waste landfills - Maintenance of cap and landfill gas collectionflare system If necessary improvements will be made - Monitoring of gas collectionflare system - Monitoring of groundwater and surface water quality and - Construction of a site perimeter security fence

The cap reconstruction is extensive and would include the following activities

- Excavation of the existing vegetated topsoil - Temporary storage of the excavated soil - Removal of existing surface drainage facilities - Protection and raising of existing gas collection manholes - Regrading to establish required slopes - Upgrading the existing low permeability soil layer to achieve 24 inches of soil with a maximum permeability of 1 x 10-7 cmsec - Testing of the upgraded low permeability layer to assure design standards are achieved


- Installation of a flexible membrane liner (FML) component directly above the upgraded low permeability soil layer - Installation of a soil drainage layer above the FML to drain the immediate and upgradient areas of the landfill - Installation of a geotextile filter between the drainage layer and upper vegetative layer - Installation of the vegetative support layer consisting of a minimum 24-inch layer of soil - Re-establishment of vegetative cover - Construction of required surface water runoff control facilities and - Erosion control during construction activities

Estimated Time for Design and Construction 2 12 years Estimated Period for Operation 30 years Estimated Capital Cost S12799000 Estimated Operation and Maintenance Cost fnet present worth) S901000 Estimated Total Cost fnet present worth) Sl3700000

Alternative 5A Total Reconstruction of Landfill Cap with Qroundwater Extraction and Treatment Alternative 5A contains all components of Alternative 5 Alternative 5A also includes

- Construction operation and maintenance of a groundwater extraction system along the eastern side of the landfill - Construction operation and maintenance of and on-site groundwater treatment system and - Discharge of treated groundwater to surface water

Estimated Time for Design and Construction 2 12 years Estimated Period for Operation 30 years Estimated Capital Cost S19992000 Estimated Operation and Maintenance Cost fnet present worth) $4310000 Estimated Total Cost fnet present worth) $24302000

Summary of the Comparative Analysis of Alternatives

EPA uses nine criteria to evaluate each remedial alternative retained for detailed analysis in the FS The nine criteria are used to select a remedy that meets the national Superfund program goals of protecting human health and the environment maintaining protection over time and minimizing untreated waste Definitions of the nine criteria and a summary of EPAs evaluation of the alternatives using the nine criteria are provided below

1 Overall Protection of Human Health and the Environment addresses how an alternative as a whole will protect human health and the environment This includes an assessment of how public health and environmental risks are properly eliminated reduced or controlled through treatment engineering controls or institutional controls

The Preferred Alternative for addressing contamination at the Shaffer Landfill would provide overall protection by preventing direct contact and ingestion of site contaminants reducing the volume of leachate production and minimizing erosion of the landfill into surrounding wetlands Further


protectiveness is provided by the collection and off-site treatment and disposal of leachate

Alternatives 2 3 3A 4 4A 5 and 5A would also provide overall protection but to varying degrees In general cap effectiveness and erosion protection increase from Alternative 2 to Alternative 5 The Preferred Alternative is very close to Alternative 5 in terms of cap effectiveness and erosion protection In addition the A alternatives provide additional protection by treating groundwater Alternative 2 is the least protective and Alternative 5A is the most protective Only Alternative 1 the no action alternative would not meet this criterion Under Alternative 1 there is a cap in place however it is not properly maintained and access to the site is not adequately restricted

2 Compliance with Applicable or Relevant and Appropriate Requirements (ARARs) addresses whether or not a remedy complies with all State and Federal environmental and public health laws and requirements that apply or are relevant and appropriate to the conditions and cleanup options at a specific site If an ARAR cannot be met the analysis of the alternative must provide the grounds for invoking a statutory waiver

The Preferred Alternative and Alternatives 2 through 4 in the detailed analysis in the FS would meet all ARARs Alternative 1 would not meet MCLs and Massachusetts Groundwater Quality Standards Alternatives 5 and 5A would not meet wetlands ARARs because they necessitate the filling of wetlands in order to meet slope requirements

3 Long-term Effectiveness and Permanence refers to the ability of an alternative to maintain reliable protection of human health and the environment over time once the cleanup goals have been met

Alternatives 1 and 2 do not meet this criterion because they contain no measures to address leachate or groundwater In general the long-term effectiveness and permanence of the alternatives increases from Alternative 2 to Alternative 5 because of increasing cap stability The Preferred Alternative comes very close to being the equal of Alternative 5 in terms of cap stability In addition all alternatives require operation and maintenance to ensure they are protective over time The amount of operation and maintenance required is related to cap stability more stable caps require less operation and maintenance Again the Preferred Alternative comes very close to being the equal of Alternative 5 in terms of requiring relatively less operation and maintenance effort because of cap stability

4 Reduction of Toxicity Mobility or Volume through treatment are three principal measures of the overall performance of an alternative The 1986 amendments to the Superfund statute emphasize that whenever possible EPA should select a remedy that uses a treatment process to permanently reduce the level of toxicity of contaminants at the Site the spread of contaminants away from the source of contamination and the volume or amount of contamination at the Site


Alternatives 1 2 and 5 do not provide a reduction of toxicity mobility or volume through treatment Alternatives 3 4 and the Preferred Alternative reduce toxicity mobility and volume through treatment by collecting leachate and treating and disposing of it off-site Alternatives 3A 4A and 5A reduce toxicity mobility and volume through treatment by extraction and treatment of groundwater In addition Alternatives 3A and 4A also contain provisions for leachate collection and treatment

5 Short-term Effectiveness refers to the likelihood of adverse impacts on human health or the environment that may be posed during the construction and implementation of an alternative until cleanup goals are achieved

With the exception of Alternative 1 the Preferred Alternative and all of the alternatives retained for detailed analysis in the FS would have limited short-term impacts With Alternatives 2 through 5A and the Preferred Alternative the potential exists for erosion and associated damage to wetlands during landfill cap repair and reconstruction activities Erosion control precautions would limit adverse impacts during implementation Additionally the implementation of Alternatives 5 and 5A would require the filling of wetlands The alternatives with leachate collection require excavation through areas of known leachate outbreak Because of the potential risk associated with these activities engineering precautions would be needed to minimize the risk of contaminant emissions and ensure short-term protection of workers residents and the environment Because Alternatives 3 4 and the Preferred Alternative require transporting the leachate off-site some short-term risk exists Alternatives 5 5A and the Preferred Alternative require significant new cap material As a result there would be significant daily truck traffic in the community throughout the relatively long implementation period of these alternatives Alternatives 1 2 and 5 would have no short-term impact on the floodplain Alternatives 3 3A 4 4A and 5A would have short term impacts on the floodplain during limited construction activities which would need to take place within the floodplain

6 Implementability refers to the technical and administrative feasibility of an alternative including the availability of materials and services needed to implement the alternative

Except for Alternatives 5 and 5A all alternatives retained for detailed analysis are technically and administratively implementable To provide the necessary slope for the Landfill under Alternatives 5 and 5A a portion of the Boston amp Maine railroad tracks would be covered and wetlands would be filled making these alternatives technically and administratively difficult to implement Alternatives 5 and 5A also present implementation concerns because they require the procurement hauling and handling of large volumes of materials necessary for cap reconstruction The Preferred Alternative would also require a significant volume of material although it requires less material than Alternatives 5 and 5A This could present some minor problems in implementing this alternative


7 Cost includes the capital (up-front) cost of implementing an alternative as well as the cost of operating and maintaining the alternative over the long-term and net present worth of both capital and operation and maintenance costs

The capital operation and maintenance and total cost for each alternative is provided as part of the Site description in the preceding sections on EPAs Preferred Alternative and Other Alternatives Evaluated in the FS

8 State Acceptance addresses whether based on its review of the RIFS and Proposed Plan the State concurs with opposes or has no comment on the alternative EPA is proposing as the remedy for the site

9 Community Acceptance addresses whether the public concurs with EPAs Proposed Plan Community acceptance of this Proposed Plan will be evaluated based on comments received at previous public meetings and during the public comment period

According to the National Contingency Plan (NCP) of the nine criteria protection of public health and compliance with all applicable and relevant and appropriate requirements are considered threshold requirements that must be met by all remedies EPA balances its consideration of alternatives with respect to long-term effectiveness and permanence reductions of toxicity mobility or volume through treatment short-term effectiveness implementability and cost State and community concerns are considered as modifying criteria factored into a final balancing of all criteria to select a remedy Consideration of State and community comments may prompt EPA to modify aspects of the preferred alternative or decide that another alternative considered provides a more appropriate balance

EPAs Rationale for Proposing the Preferred Alternative

Based on current information and analysis of the RI and FS reports EPA believes that the Preferred Alternative for the Shaffer Landfill is consistent with the requirements of the Superfund law and its amendments specifically Section 121 of CERCLA and to the extent practicable the NCP Except for the No Action alternative all of the alternatives presented in this Supplement to the Proposed Plan would provide some degree of overall protection of human health and the environment In EPAs analysis however the Preferred Alternative identified in this Plan provides protectiveness equal to or greater than the other alternatives considered while still meeting all ARARs At the same time the final cap in the Preferred Alternative approaches the overall protectiveness permanence and stability of the cap described in Alternatives 5 and 5A while involving less construction and no adverse affect on the wetlands EPA believes that this alternative would effectively reduce the migration of contaminants off-site Groundwater and surface water quality testing would monitor the effectiveness of this alternative and the possible necessity of further action In addition in EPAs estimation the preferred alternative would achieve the best balance among the criteria used by EPA to evaluate the


alternatives The preferred alternative would provide short and long-term protection of human health and the environment would attain all Federal and State applicable or relevant and appropriate public health and environmental requirements (ARARs) would reduce the volume and toxicity of contaminated leachate and would utilize permanent solutions to the maximum extent practicable In sum the Preferred Alternative would provide overall protection and long-term effectiveness greater than all other evaluated alternatives except Alternatives 5 and 5A (which do not meet ARARs)

For Mor Information

If you have any questions about the site or would like more information you may call or write to

Don McElroy Remedial Project ManagerUS Environmental Protection AgencyWaste Management Division (HEC-CAN6) JFK Federal Building Boston MA 02203 (617) 223-5571 or Doug GutroCommunity Relations CoordinatorUS Environmental Protection AgencyPublic Affairs Office (RPA) JFK Federal Building Boston MA 02203 (617) 565-3383


Glossary Ambient Water Quality Criteria Concentration values of toxic pollutants in navigable waters that based on available data will not result in adverse impacts on important aquatic life or on consumers of such aquatic life

Applicable or Relevant and Appropriate Requirements (ARARs1 ARARs include any State or Federal statute or regulation that pertains to protection of public health and the environment in addressing certain site conditions or using a particular cleanup technology at a Superfund site A State law to preserve wetland areas is an example of an ARAR EPA must consider whether a remedial alternative meets ARARs as part of the process for selecting a cleanup alternative for a Superfund site

Aquifer A layer of rock or soil that can supply usable quantities of groundwater to wells and springs Aquifers can be a source of drinking water and provide water for other uses as well

Baseline With respect to the alternatives evaluated a statement of existing conditions and their relative consequences should no further action be taken

Comprehensive Environmental Response Compensation and Liability Act (CERCLA) A Federal law passed in 1980 and modified in 1986 by the Superfund Amendments and Reauthorization Act (SARA) The act created a special tax that goes into a Trust Fund commonly known as Superfund to investigate and clean up abandoned or uncontrolled hazardous waste sites Under the program EPA can either l) pay for site cleanup when parties responsible for the contamination cannot be located or are unwilling or unable to perform the work or 2) take legal action to force parties responsible for site contamination to clean up the site or pay back the Federal government for the cost of the cleanup

Feasibility Study (FS) Report Report that summarizes the development and analysis of remedial alternatives that EPA considers for the cleanup of Superfund sites

Groundwater Water found beneath the earths surface that fills pores between materials such as sand soil gravel and cracks in bedrock and often serves as a principal source of drinking water

Maximum Contaminant Levels (MCLs) The maximum permissible level of a contaminant in water that is consumed as drinking water These levels are determined by EPA and are applicable to all public water supplies

National Pollutant Discharge Elimination System (NPDES) The national program for issuing modifying monitoring and enforcing permits and imposing and enforcing pretreatment requirements under the Clean Water Act

National Priorities List (NPL) EPAs list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund Parts per Billion (ppb) A unit of measurement used to describe levels of contamination For example one gallon of a solvent in one billion gallons water is equal to one part per billion


Plume A three dimensional zone within the groundwater that contains contaminants and generally moves in the direction of and with groundwater flow

Pretreatment Treatment of wastewater performed prior to discharge to a public sewer system

Record of Decision (ROD1 A public document that explains the cleanup alternative to be used at a National Priorities List (NPL) site The ROD is based on information and technical analysis generated during the RIFS and on consideration of the public comments and community concerns

Remedial Alternative Option evaluated by EPA to address the source andor migration of contaminants at a Superfund site to meet health based cleanup goals

Remedial Investigation fRI) The Remedial Investigation determines the nature and extent and composition of contamination at a hazardous waste site and directs the types of cleanup options that are developed in the FS

Sediments The sand or mud found at the bottom and sides of bodies of water such as creeks rivers streams lakes swamps and ponds Sediments typically consist of soil silt clay plant matter and sometimes gravel

Solvents Liquids capable of dissolving other liquids or solids to form a solution The chief uses of industrial solvents are as cleaners and degreasers Solvents also are used in paints and Pharmaceuticals Solvents used in foundries and other industrial applications are frequently VOCs Many solvents are flammable and toxic to varying degrees

Source Area at a hazardous waste site from which contamination originates

Surface Water Bodies of water on the surface of the earth such as rivers lakes and streams

Volatile Organic Compound (VOC A group of chemical compounds composed primarily of carbon and hydrogen that are characterized by their tendency to evaporate (or volatilize) into the air from water or soil VOCs include substances that are contained in common solvents and cleaning fluids Some VOCs are known to cause cancer

Wetlands Areas such as marshes bogs and swamps that are saturated with water long enough each year to affect the type of soil and vegetation found in the area Wetlands are federally protected because they purify water prevent floods feed and shelter fish and wildlife and offer recreational opportunities


Figure 1

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Key Site Features Map Iron Horse Park Site Billerica MA

Figure 1illmipp] 20 Shaffer Landfillsupplement to the Proposed Plan

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3 provides a brief description of the Preferred Alternative and other alternatives evaluated in the FS

4 outlines the criteria used by EPA to propose an alternative for use at the site and briefly analyzes whether the alternatives meet each criteria and

5 presents EPAs rationale for its preliminary selection of the preferred alternative

To help the public participate in reviewing the cleanup options for the Landfill this document also includes information about where interested citizens can find more detailed descriptions of the remedial process and the alternatives under consideration for the Shaffer Landfill section of the Iron Horse Park Site

THE PUBLICS pOfrF TN EVALUATING REMEDIAL ALTERNATIVES

PUBLIC INFORMATIONAL MEETING

On January 15 1991 EPA held a public informational meeting at 730 pm in the Billerica Town Hall to describe the Proposed Plan and other alternatives evaluated in the Feasibility Study (FS) Following the presentations EPA held a question and answer period

PUBLIC COMMENT PERIOD ON PROPOSED PLAN

EPA conducted a 60 day-public comment period from January 16 to March 16 1991 to provide an opportunity for public input on the agencys Proposed Cleanup Plan and Feasibility Study

PUBLIC COMMENT PERIOD ON SUPPLEMENT TO THE PROPOSED PLAN

EPA is conducting a 30-day public comment period from May 18 to June 17 1991 to provide an opportunity for public input on the Supplement to the Proposed Plan During the comment period the public is invited to review the Supplement to the Proposed Plan and offer comments to EPA

INFORMAL PUBLIC HEARINGS

EPA conducted two informal public hearings on February 5 and February 19 1991 at the Billerica Town Hall beginning at 730 pm to accept oral comments on the cleanup alternatives considered for the Site The public hearings provided the public with opportunities to comment on the cleanup plan after they had heard the presentation at the public informational meeting and reviewed the Proposed Plan Comments made at the public hearings have been transcribed and a copy of the transcript will be added to the Site Administrative Record available at the EPA Records Center at 90 Canal Street in Boston Massachusetts and at the information repository listed on page 3


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