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'-> UNITED STATES ENVIRONMENTAL-.,~~CY

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PREFERRED ALTERNATIVE DOCUMENT

RE-SOLVE INC. SITE

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Re-Solve Inc. Site North Dartmouth, Massachusetts

II. STATEMENT OF DOCUMENTS PURPOSE

Section 117 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) requires that notice must be published and a brief analysis of the proposed plan for site remediation be made available to the public . In addition, EPA should alao provide reasonable opportunity for subtllisaion of wr:itten comments as well aa th• opportunity for a public meeting near the aite regarding the proposed plan. ·. .

This document describes the preferred remedial action altern­ative (i.e. proposed plan) for the Re-Solve, Inc. aite. Thia alternative has been selected frOill among the the altern­atives analyzed in the Feasibility Study (PS) for the aite. The preferred alternative document 1a intended to describe EPA's deciaion to the public, but the preferred alternative ia not necessarily the final re111edy selection for the site.

Thia preferred alternative document 1a aade available with the PS and other documents contained in the adminietratlve record, for public review and comment. In addition to the FS, the administrative record includes all documents such as remedial investioationa and asaociatd vorkplana, da""ta, analys­es, public comments, public meeting transcripts and other relevant material.

All documents developed and released to the public are avail ­able for public inspection and copying at the followino locations•

~~· ISouthworth Library u.s. EPA LibrarycP'/ J "" 732 Dartmouth Street JFIC Federal Building

oJ~.,J .,_ Dartmouth, MA 02748 15th Ploor ,. ' (617)999-0726 Boston, MA 02203 ~"' (6l7)S6S-3300

LI I. ROLE OF COMMUNITY IN PROCESS

Oevelopino and publishing a preferred remedial alternative document provides the public with an opportunity to comment on the Aoency's rationale for ita preferred alternative, while providino EPA with comments and information from the public that may support, retina or change the Agency's

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preference for the site. The final determination will be made available through the Record of Decision (ROD) only after consideration of all comments on all remedial alternatives addressed in the PS. Written and verbal comments will be accepted until July 7, 1987, and diecuaaed in the Reaponaive­neaa Summary of the ROD. All written comments should be aent tO I

Stephen Joyce u.s. Environmental Protection Agency Waste Management Division (HRS-1903)

JFK Federal Building Boston, Maaaachuaetta 02203

617-565-3633

EPA will hold an . informational public 111eeting on June 23, 1987 at 7 s00 p .m. at the Dartmouth Town Hall in Dartmouth, Maaaachuaetta . In addition, oral col'lllllenta can be entered into the record during a second public meeting at the Dart­mouth Town Hall on July 1, 1987 at 7t30 p.m.

IV. SCOPE OP REMEDIAL ACTIVITY

The preferred alternative is a co•prehenaive approach for aite re11ediation which includea both a aource control and llanaQeaent of migration component. Specific reaponae objective& to be met by the preferred alternative have been developed for the Re-Solve Inc. aite.l Theae objective&include t

• Reduce rhka to human health aaaociated with direct contact with conta11inanu in aurface and aub-aurface aoila and aedimenta.

• Reduce rhka to freahwater aquatic life aaaociated with contact with PCB contaminated aediments and bioaccumula­tion including sediment dwelling organhma and thoae at higher trophic levels.

• Reduce or eliminate the mobility, toxicity and volume of hazardous aubatancee, pollutant& and contaminant&.

Reduce the rhka to human health associated with dermal contact with aubaequent abaorption, inoeation of ground­water, and inhalation of volatiles released from ground­water and aurface water.

• Eliminate or minimize the threat posed to the public health, welfare and the environment from the current

Refer to Chapter 2.0 of the Re-Solve, Inc . aite draft rs, June 1987, for a more detailed diacusaion on aite reaponae objectives. Thia diacuaaion is orQanized into objective& for source control and management of migration alternative& .

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extent of contaminant migration in groundwater and surface water.

Haintatndatr quality at protective levels for on-site workers and the public r~ durlng site remediation.

V. ALTERNATIVES ANALYZED IN THE FEASIBILITY STUDY

To meet the response objectives, a variety of remedial alternatives were developed by combining technolooiea that had passed an initial screening process during the PS. Combining different technologies was necessary because individual technolo;iea would not, in themselves, remediate ~ the release of hazardous substances from the alta. The z:o alternatives considered in a detailed evaluation in the ~"' PS include source control remedial alternatives and "'' :00 ""'"' J>r

analyaie of the source control and management of migration management Of'iii'IQr~emedial alternatives. A summary --<<

~"' alternatives is presented in Appendix A.

Source Control

sc-1. No Action . This alternative includes no both aource control and management of •dgratlon,

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contaminated ao ila and groundwater. It entail• the li11ited protection provided by fencing at the eter of the aite, poating warning aigna on the fence e area of the

) ~~=~: ~~~b~~:~I~9t~~ec~~~~~tc~~v r~l~~lc d~:~la:n~~ple-X •enting a 11ultlmedh monitoring p gram No treatiHnt of

aource aoil or groundwater h prov

be tested and, if appropriate, wetlands wlll be restored.

SC-4. On Site Dechlorination. This alternative also entails excavation of contaminated soils on-site and aediments in the wetlands north of the aite and the unnamed tributary and treatment in an on-aite mobile dechlorination unit. Potassium/ polyethylene glycol (KPEG) dechlorination is a soil treatment process aultable for the treatment of large volumes of soil contaminated at low to moderate levels (1 -10,000 ppm) wlth chlorinated organics such as PCBs. Treated soils from this process will be tested and, if appropriate, used as backfill and the wetlands will be restored.

SC-7c. Encapsulation/In-Situ Treatment/Source Material Treatment. Thh alternative provides for the excavation and destruction of specific areas exhibiting high concentra­

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tiona of PCBs separately from tho rest { tho contaminated soils. The highly contaminated aourc~!terial wUl be ~ ~~==~~~·~.~~~o~~~:~~~nb~s~~;)1~~ !~~~t~:t!~~..!~~-~!;tru;ftGn~ (SC-14). Treated soils will be teated and, if appropriate, \.1,.,u used aa backfill. The purpose of the separate treatment 1a :;:..:;t to reduce the level of contamination in the remaining soils to a range suitable for in-situ soil flushing with aurfactant solution. Contaminated sediments in the wetlands north of the site and the unnamed tributary will be excavated and treated with the remaining soils by the in-situ soil flushing process. Thia alternative also includes restoration of the wetlands.

SC-14. Off-Site Thermal Destruction. This alternative entails the excavation of contaminated soils on-site and sediments in the wetlands north of the site and the unnamed tributary and transportation of the total volume of material to an off-site TSCA permitted incinerator for treataent. Excavated areas will be backfilled with clean fill and the wetlands will be restored.

Management of Migration

MOM-1. No Action. This alternative has been c011bined with the no action alternative for source control (SC-1) and described previously.

_) MOM-2a and e. On Site Groundwater Treatment. This alter­

}( native con at;!tof recirculation, pump and flush ayatem. The groundw 11 be extracted from walla located in the areas of high contamination, passed through the treat11ent facility, and dhcharged via a distribution ayate11 over the entire aite. For treatment, MOM-2a utilizes a heated air stripping tower to remove organic contaminants whereas MOM-2c utilizes an ambient air stripping tower and carbon adsorption contactors. A small portion of the treated water will be further treated with activated carbon and then discharged to the Copicut River.

MOM-4. On-Site Groundwater Pre-Treatment to Off-Site Waste­Water Facility. This alternative entails extracting contamin­ated groundwater from the overburden and bedrock aquifere , treating it on-site with precipitation and air stripping, and transporting it off-si pipeline to a local waste­water treatment plant fo tina · tr atment and disposal.

The alternatives Hs~v :::dis seed in detall in the Re-Solve, Inc. draft 1 , available for public review at the previo sted locations.

Description of the Preferred Alternative

The preferred alternative selected for implementation at

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the Re-Solve, Inc . site is consistent with the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA}, the Superfund Amendments and Reauthorization Ac t o f 1986 (SARA) and the National Contingency Plan (NCP) 1 40 CFR Pa r t 300 !l• .!.!.9.·, 47 Feder al Reg ister 31180 July 16, 198 2 , as ame nded.

A. Summary o f the Ma jor Components o f the Preferred Al t e r na tive.

The preferr ed alternative for the Re-Solve , Inc . si t e i nc ludes both a source control and management of migration component.

The s ource control component en t a ils excavation of PCB contamina~eoils located in the uns aturated zone and

~~~~~T~~t ~a .~~~;t~~~~!~•p~~~:!~ri 8 o~.:~~Ui~~ e reatm of PCBa in soils but it 1 ~ om

the laboratory testa, that thh proce e tive in removing a percentage of other organics rom the ~ .1. This alternat i ve requires extensive on-site handlingAof ~~-

·~~~ _,~~~l ~~~~==~:a:~~ :~~!~t~:~o~~~o~;f~:~t!i!~~ra:~o~no;f~~~~.!~ '~ '-011\.E. ,..4- ~ ";.._ inated fugitive duet and odors, the method of excavation u, Oc.~...U...~ ...... ~ vill be restricted to sheet piling vertical cute. This

approach will reduce open air removal of contaminated c.~ ....... -""""' ­ soils and thus limit the potential for emissions. Into.o.....fho..c..t.....&..\•oJ~.J addition to on-site soils, PCB contaminated aedimenu h.~ ~ca.~• ..... ...O will be excavated from the wetlands north of the site and ~w 'r"'""\0\,.4.....>c...H." the unnamed tributary and treated on-aite in the dechlor•

ination facility. Treated soils will be tested and, if'-\,....,""'+\o..,l wh.~\..l appropriate, used •• backfill. These soils will be ::H\.Q...I(./0.~"1 I~ further treated to reduce the level of volatile organic 1.\,••H\/~\·""+ 't'\o .. compounds aa part of the management of migra onent.

The site will be regraded and revegetated, nd the w tlanda ., ..,\"\ , u.S) 4-c.~ will be r estored . Because dechlorinatio is ~nno ative 0~ ""\I'(. \---c.c.+ . technology and i s only proven on a labor tor~cale evel,

an intensive pilot s tudy is required to aeertain e e f fecti veness i n relliOVi ng PCBa and other nants from t he Re-Solve soils . If dechlorination, baaed on the r e s ults of the p i lot seale study , h determined not to be e ffective in t he t r eatment o f the a l te-spec ifle was t e, the Agency vill s elect on-site thermal destructi on (SC- 2) aa the source control remedia l a l te rna tive.

The management of migration compone nt cons i sts o f a recirculation, pump and flush system. Th is component will be implemented after the source control remedial action has been completed. The groundwater will be extracted from wells located in areas of high contamina· tion, passed through the treatment facility, and discharged via a distribution system over the entire site. The soils within these areas will be flushed by this process

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2. Table 4-1, •calculation of Soil PCB Cleanup Levels for the Re­Solve, Inc. Site.• Re-Solve draft FS, June 1987.

Refer to Chapter 4 of the Re-Solve draft FS for a dlae1,1asion on the variability and uncertainty aa•ociated vith aoil cleanup level•.