Environmental Protection Agency-Region 3Superfund Program

PROPOSED PLAN

AVCO Lycoming SiteWilliamsport, Pennsylvania April 1991

Introduction

The U. S. Environmental Protection Agency Region III (EPA) hasidentified a preferred alternative for remediating ground waterat the AVCO Lycoming facility located in Williamsport,Pennsylvania. The selection of this alternative is based on therecently submitted draft Remedial Investigation and FeasibilityStudy (RI/FS) prepared by Textron Lycoming. This ProposedRemedial Action Plan (Plan) summarizes the draft RI/FS report,and subsequent comments to that report, identifies the remedialalternative preferred by EPA, and explains the reasons for thispreference.

The preferred alternative addresses groundwater in the overburdenand bedrock aquifers that has become contaminated as a result ofpast disposal practices at the AVCO Lycoming facility. Beforeselection of a final remedy, EPA will consider written and oralcomments on the proposed alternatives. Therefore, the public isencouraged to review and comment on all the alternativesidentified in this Plan.

This Plan has been prepared by the EPA to facilitate publicparticipation in the decision-making process regardingremediation of the site. The Plan:(l.) fulfills the publicnotification requirements of Section 117(a) of the ComprehensiveEnvironmental Response, Compensation and Liability Act (CERCLA,commonly known as Superfund) of 1980, as amended, 42 U.S.C.§9617; 2.) describes the remedial alternatives evaluated in thedraft RI/FS and subsequent comment documents; 3.) identifiesEPA's preferred alternative and explains why the Agency prefersit; 4.) solicits community involvement in the selection of aremedy; and 5.) refers interested parties to the RI/FS and othersite-related documents housed in the local information andadministrative repositories at the James V. Brown Library ofWilliamsport and Lycoming County, in Williamsport, Pennsylvania.

EPA encourages the public to review site-related materials inorder to have a more comprehensive understanding of the Superfundactions that will be occurring at the AVCO Lycoming site. Whilethis document highlights key information from the RI/FS report,more complete sources of information regarding the remedialaction are the RI/FS report and the site administrative record.

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Copies of the FS report and the administrative record can bereviewed at the James V. Brown library. It is expected that arevised FS will be added to the administrative record inapproximately one month. That FS, however, is not expected todiffer significantly from the remedies described in this proposedplan and as reflected in the subsequent documentation settingforth the States' comments and other documentation.

Public comments about the remedial actions described in thisProposed Plan will be accepted by the EPA representatives listedat the end of this document during the public comment period thatbegins on April 17, 1991 and closes on May 16, 1991. A publicmeeting to discuss the Proposed Plan will be held on May 2, 1991at the Sheraton Hotel at 7:00 P.M. If there are any questionsconcerning the public meeting, please contact Eugene Dennis orAmy Barnett at the address or telephone numbers listed at the endof this Plan.

Site Background

The AVCO Lycoming facility is located at 652 Oliver Street inLycoming County, Williamsport, Pennsylvania (see Site LocationMap). The facility is approximately 28 acres and is situatednext to a residential neighborhood with some small industry. Twopublic parks are located within the residential area that includebaseball fields, a public swimming pool, skateboard park andplayground.

Portions of the AVCO Lycoming property were first used formanufacturing purposes around the turn of the century.Manufacturing operations consisted of a bicycle and sewingmachine manufacturing facility, a sandpaper plant, a tool and dieshop and a silk plant. During the 1920's the plant property waspurchased by AVCO Corporation and plant operations centeredprimarily on the manufacture and repair of aircraft engines.Prior to 1940, automobile and boat engines were also produced atthe plant. During World War II, and perhaps for several yearsfollowing the war, it is believed that sections of the plant wereleased to or owned by certain other entities, including theDefense Plan Corporation and the Reconstruction FinanceCorporation for manufacturing, research and development projects.Little information exists regarding the foregoing activities.

In February 1980, Textron acquired AVCO Lycoming Corporation,which includes the AVCO Lycoming Williamsport Division. AVCOremains a wholly-owned subsidiary of Textron. The facility isnow known as Textron Lycoming, but it will be referred to as AVCOLycoming in this Plan.

The AVCO Lycoming site contains several potential areas ofconcern including a "dry well", coolant water well, past plating

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areas, a temporary sludge holding lagoon, degreasing areas andchemical storage areas. These areas were identified throughemployee interviews, employees' general knowledge of planthistory and aerial photographs. The "dry well", it is believed,consisted of an old septic basin that was reportedly used forwaste disposal until it was sealed in the middle 1950's. Thecoolant water well, drilled in the 1930's and located in themiddle of the plant, may have intercepted floor wash residueuntil it was covered. The past plating areas are of concern as aresult of cadmium, chromium, copper, tin, lead, nickel and blackoxide plating that took place over the years. A temporary sludgeholding lagoon was used for three or four years during the 1950'sto hold sludge from the waste water treatment plant. The sludgewas eventually shipped off-site for disposal and the lagoon wasbackfilled. Solvents used in previous degreasing locations areknown to have leaked or spilled on the plant floor possiblyentering the plant sewer system or other areas of the plant.Chemical storage existed primarily in areas where they were usedfor manufacturing processes. Temporary chemical storage areaswere also located in the east end of the plant, and near theexperimental laboratory in the north end of the plant.

The plant has approximately 40 underground storage tanks thathave stored products such as varsol, jet fuel and diesel fuel inthe past. Many of these tanks have been taken out of service andare presently being abandoned or upgraded in accordance withunderground storage tank (UST) regulations.

The AVCO Lycoming site was placed on the National Priorities List(NPL) on February 12, 1990 having a score of 42.24. Between 1989and 1991, an RI/FS was conducted by Textron Lycoming under theguidance of EPA and the Pennsylvania Department of EnvironmentalResources (PADER). The RI/FS was conducted to identify thetypes, quantities and locations of contaminants and to developways of addressing the contamination problems. The RI included arisk assessment that determined which of the contaminantsdetected posed a risk to human health or the environment. Theresults of the RI are as follows:

1. The shallow ground water in the overburden on-site iscontaminated with trichloroethylene (TCE), 1,2-dichloroethylene (DCE) and vinyl chloride. The shallowground water in the overburden off-site is contaminated withTCE and DCE.

2. The shallow ground water in the overburden in the westernsection of the plant is contaminated with total chromium andhexavalent chromium.

3. The ground water in the bedrock on-site and off-site iscontaminated with TCE, DCE and vinyl chloride.

4. On-site soil samples have concentrations of lead andchromium above background levels.

5. The total volatile organic compound (VOC) concentrations inon-site soil samples are low, and consist primarily ofxylene, ethylbenzene, and TCE.

6. The surface water quality of Lycoming Creek is not affectedby the site.

Scope and Role of Operable units

This is the first remedy proposed by EPA for the AVCO Lycomingsite. However, the groundwater is currently being monitoredunder a quarterly monitoring program, conducted in accordancewith a November 1985 Consent Order between PADER and TextronLycoming. This remedy is expected to address all of the mediaaffected by the contamination at the site. Splitting the siteinto smaller components called operable units to addressindividual media is not warranted at this time.

Summary of site Risk

During the RI/FS an analysis that is commonly referred to as abaseline risk assessment (RA) is performed. The RA normallyevaluates the current and potential risk(s) to human andenvironmental populations when no further remedial action occursat a site.

At the AVCO Lycoming site, some remedial response has alreadytaken place pursuant to the PADER Consent Order The currentactions include three groundwater recovery wells on-site andassociated treatment. Groundwater recovery and treatment is alsooccurring off-site at Elm Park, at Third Street, and at theWilliamsport Municipal Water Authority (WMWA). These operationshave helped to control the migration of contaminated groundwater.

The RA section of the RI/FS for this site evaluated the healtheffects of site contaminants on the following potentially exposedpopulations: residents who currently live and work in thesurrounding area and may inhale compounds volatilizing from on-site soils; current recreational users of Elm Park near the airstrippers; current workers on-site (who may inhale compounds fromsoils and air strippers); residents near the site and ThirdStreet air strippers; current recreational users of LycomingCreek; hypothetical users of on-site and off-site ground water asa drinking water source in the future; and current users oftreated ground water from the WMWA production well field thatservices Williamsport.

The RI showed that on-site soils and groundwater at the AVCO site

contain moderate to high levels of organic and inorganiccontaminants. The two major inorganic constituents found in thesoils are lead and chromium. Lead was detected at concentrationsof 169 ppm and 185 ppm at the eastern end of the site property.The highest chromium concentrations detected were 437 ppm nearthe center of the site and 1,120 ppm beneath the Human Resourcesbuilding, which no longer stands. The shallow ground water inthe overburden in the western section of the site contains totalchromium and hexavalent chromium at concentrations of 9,250 ppband 10,000 ppb, respectively.

The primary VOCs found in the groundwater at the AVCO siteinclude TCE, DCE and vinyl chloride. The shallow groundwater inthe overburden on-site contains concentrations of TCE up to17,000 ppb and DCE up to 7,000 ppb. Vinyl chloride was alsodetected in the shallow ground water on-site at concentrations of520 ppb. The ground water in the bedrock on-site containsconcentrations of TCE up to 13,000 ppb and DCE up to 8,400 ppb.

The direction of groundwater flow at the AVCO site is generallyto the south toward Lycoming Creek and the WMWA well field.Contaminated groundwater has migrated from the AVCO facility inthe direction of the well field. The shallow ground water in theoverburden off-site contains concentrations of TCE at 2,900 ppband DCE at 980 ppb. The ground water in the bedrock off-sitecontains concentrations of TCE at 730 ppb and DCE at 170 ppb.

Based on the information collected during the RI, the RAidentified 11 scenarios that were associated with ground water,soil, surface water, air and sediment at and around the AVCOsite. Currently, carcinogenic risks due to treated waterprovided by the WMWA, on-site soils, Lycoming Creek surface waterand sediment, and air emissions from the air strippers on-siteand off-site are at or below the acceptable level of 10"6. Thislevel is equivalent to 1 extra chance in 1,000,000 of contractingcancer due to exposure to site-related contaminants.

However, the on-site and off-site contaminated ground watercontribute future risks for potential ground water users. Thefollowing scenarios describe conservative risks due tohypothetical exposures to site-related contaminants, as presentedin the RA.

The untreated ground water in the WMWA well field and the groundwater in the monitoring wells located on Third Street present anexcess human cancer risk presently estimated at 3.25xlO"2. Thisrisk is primarily due to TCE present at a maximum concentrationof 19,000 ppb in 1988 in a monitoring well near Third Street.The range of values for this scenario is 0.2 ppb and 1,900 ppbwith an average value of 317 ppb. This risk evaluationrepresents a highly conservative estimate of human health riskand means that individuals exposed to ground water in this area

have 32,500 extra chances out of 1,000,000 of contracting cancer.Due to the conservative nature of this assessment, however, theactual health risks will probably be lower.

The off-site overburden ground water in the Elm Park areapresents an excess human cancer risk presently estimated at2.97xlO"2. The risk is primarily due to beryllium and TCEpresent at maximum concentrations of 3.5 ppb and 860 ppb,respectively. The range of values for beryllium is 0.4 ppb and3.5 ppb, and for TCE, the range is 1.1 ppb and 860 ppb. Theevaluation represents a highly conservative estimate of humanhealth risk and means that individuals exposed to ground water inthis area have 29,700 extra chances out of 1,000,000 ofcontracting cancer. Due to the conservative nature of thisassessment, however, the actual health risks will probably belower.

The on-site overburden ground water presents an excess humancancer risk presently estimated at 9.53xlO"1. The risk isprimarily due to vinyl chloride present at a maximumconcentration of 1,100 ppb in 1988 in a sample from an on-sitemonitoring well. The range of values for this scenario is 1 ppband 1,100 ppb with an average value of 126 ppb. This riskevaluation represents a highly conservative estimate of humanhealth risk and means that individuals exposed to ground water inthis area have 953,000 extra chances out of 1,000,000 ofcontracting cancer. Due to the conservative nature of thisassessment, however, the actual health risks will probably belower.

The off-site bedrock ground water presents an excess human cancerrisk presently estimated at 2.39xlO"2. The risk is primarily dueto TCE present at a maximum concentration of 1,200 ppb in asample from a monitoring well located south of Third Street. Therange of values for this scenario is 0.5 ppb and 1,200 ppb withan average of 439 ppb. This risk evaluation represents a highlyconservative estimate of human health risk and means thatindividuals exposed to ground water in this area have 23,900extra chances out of 1,000,000 of contracting cancer. Due to theconservative nature of this assessment, however, the actualhealth risks will probably be lower.The on-site bedrock ground water presents an excess human cancerrisk presently estimated at 9.89xlO"1. The risk is primarily dueto vinyl chloride and TCE present at maximum concentrations of250 ppb and 19,000 ppb, respectively. The range of values forvinyl chloride is 1.0 ppb and 250 ppb with an average of 53 ppb.The range of values of TCE is 0.5 ppb and 19,000 ppb with anaverage of 2,838 ppb. This risk evaluation represents a highlyconservative estimate of human health risk and means thatindividuals exposed to ground water in this area have 989,000extra chances out of 1,000,000 of contracting cancer. Due to the

conservative nature of this assessment, however, the actualhealth risks will probably be lower.

Actual or threatened releases of hazardous substances from thissite, if not addressed by the preferred alternative or one of theother remedial measures considered, present a current orpotential threat to public health, welfare, or the environment.

Scope and Role of Remedial Action

At this site the most significant risk is via the on-site andoff-site contaminated ground water. As such, EPA plans tomitigate the threat posed by this media.

The contaminated ground water plume has migrated south towardLycoming Creek and the WMWA. Although the exiting on-site groundwater recovery and treatment system has been effective inremoving VOCs from groundwater, it has not prevented the off-site migration of contaminated ground water. Therefore, thepreferred strategy for remediating the contaminated ground wateris to prevent the off-site migration with additional recoverywells and to treat the recovered ground water on-site. The off-site contaminated ground water will continue to be remediated bythe existing recovery and treatment systems, which will beenhanced by additional recovery.

The on-site contaminated soils do not threaten ground waterquality, nor do they pose a risk via inhalation or dermalcontact. Therefore, the proposal remediation for the siteinvolves only ground water recovery, treatment and disposal.

Institutional controls for potential exposure to contaminatedsoils via direct contact'will be addressed as part of theselected remedy.

Summary of Alternatives

The Superfund process requires that the alternative chosen toclean up a hazardous waste site meet several criteria. Thealternative must protect human health and the environment, becost-effective, and meet the requirements of all state andfederal laws and regulations. Permanent solutions tocontamination problems should be developed, whenever possible.These solutions should reduce the volume, toxicity, or mobilityof the contaminants. Emphasis is also placed on treating thewastes at the site, whenever this is possible, and on applyinginnovative technologies to clean up the contaminants.

In the FS for the site, a screening of technologies applicable toremediating the contaminated media was completed. Thetechnologies were screened according to their effectiveness andimplementability. Those technologies determined to be most

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applicable were then developed into remedial alternatives.Alternatives GW-1 through GW-5 have passed the screening and areretained. In addition, the EPA has added the No ActionAlternative (Alternative 1) as required by the Nation ContingencyPlan. Therefore, the following sets forth the list ofalternatives:

Alternative 1: No ActionAlternative GW-1: No Further ActionAlternative GW-2: Limited ActionAlternative GW-3: Ground Water Collection, Chemical

Treatment for Metals, Air Stripping,Emissions Controls, and Discharge ofTreated Water.

Alternative GW-4: Ground Water Collection, ChemicalTreatment for Metals, ChemicalOxidation, and Discharge of TreatedWater.

Alternative GW-5: Ground Water Collection, ChemicalTreatment for Metals, Air Stripping,Emissions Controls, Reinjection andDischarge of Treated Water, and In-SituBiological Treatment.

Common Elements

Except for the "No Action" alternative, all of the remainingalternatives for the Site include the continued operation of theexisting groundwater recovery wells.

Alternative 1

The National Contingency Plan (NCP) requires that a no actionalternative be evaluated as a baseline for comparison to otheralternatives. Under this alternative, no remedial action wouldbe taken at the site. The exiting groundwater extraction andtreatment systems would not be operated, however, groundwatermonitoring would continue.

At the AVCO Lycoming Site, remedial actions have already beenundertaken, pursuant to a Consent Order and agreement with PADER.Thus, a true no-action alternative is not possible. The bestapproximation of a no-action alternative is ceasing currentactions, that is shutting off the on-site and off-sitegroundwater extraction system. The no-action alternative wouldinclude groundwater monitoring consisting of sampling andanalysis in accordance with the existing PADER Consent Order andAgreement.

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Alternative GW-1

Annual O&M Cost; $10.100Present Worth: $160.000

Under this alternative, EPA would take no further action beyondthe continued operation of the existing groundwater recovery andtreatment at the site to prevent exposure to the contaminatedmedia or to reduce risk at the site.

Alternative GW-2

Capital Cost; $48.000Annual O&M Cost; $11.300Present Worth; $220.000

This alternative consists of institutional controls includingdeed, zoning, and/or ownership restrictions to limit futureproperty use to those activities compatible with site conditions.This alternative would also involve the construction andmaintenance of a fence around the western portion of the site toprevent unauthorized entrance in this area.

Alternative GW-3

Capital Cost; $2.500,000Annual O&M Cost; $ 442.700Present Worth; $9.300.000

This alternative consists of a ground water recovery system tocontain contaminated ground water on-site. The portion of therecovered ground water containing elevated levels of chromium andother metals would be chemically treated. Recovered ground waterwould be air stripped for VOC removal and the off-gas from theair stripper would be treated by the best available controltechnology. The treated ground water would be discharged toLycoming Creek. This alternative also includes additional off-site groundwater recovery and treatment in the vicinity of ElmPark. This additional off-site groundwater recovery andtreatment has been added to Alternative GW-3 contained in thedraft FS. In addition, institutional controls have been added tothis Alternative in the form of limiting future property use.

Alternative GW-4

Capital Cost; $2.400,000Annual O&M Cost; $525.700Present Worth: $10.000,000

Alternative GW-4 is the same as Alternative GW-3, except for theuse of chemical oxidation for VOC removal instead of air

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stripping. The effluent from the oxidation unit would dischargeddirectly to Lycoming Creek.

Alternative GW-S

Capital Cost: $3.300.000Annual O&M Cost; $650.000Present Worth; $13.000.000

Alternative GW-5 consists of the same components as GW-3 plus in-situ biological treatment for ground water beneath the site. Theground water recovery well system for this alternative would bethe same as that described in Alternative GW-3, but the dischargescenario would be different due to the need for upgradientreinjection of ground water to facilitate in-situ bioremediation.Since inorganic contaminants are mainly confined to the westernportion of the site, this ground water would be treated formetals, and the entire recovered stream would be treated forVOCs.

Evaluation of Alternatives and the EPA Preferred Alternative

After careful consideration of the proposed remedial alternativeand subsequent comments to those alternatives, EPA's preferredalternative for the AVCO Lycoming site is Alternative GW-3.Under this alternative, ground water recovery wells would beinstalled on the downgradient side of the facility to containcontaminated ground water and control further migration. Thecontaminated ground water would be recovered through a series ofexisting and newly installed recovery wells. The recoveredground water would be chemically treated for metals and airstripped for VOCs. The vapor phase from the air stripper wouldbe treated by the best available control technology and thetreated ground water would be discharged to Lycoming Creek. Theoff-site contaminated ground water will be recovered and treatedthrough the existing off-site recovery wells. This off-sitesystem will be modified to include additional recovery andtreatment in the vicinity of the Elm Park area. In addition,institutional controls have been added to this alternative in theform of limiting future property use.

Based on currently available information, the EPA anticipatesthat this alternative will be protective of human health and theenvironment. In evaluating remedial alternatives, the EPAconsiders nine specific criteria (see Table 1).

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Table 1. DB8CRIPTZOM OF BVALUATIOM CRITERIA

addresses whether or not a remedy will: cleanup a site to withinthe risk range; result in any unacceptable impacts; control theinherent hazard (e.g., toxicity and mobility) associated with asite; and minimize the short-term impacts associated withcleaning up the site.Compliance with ARAR's - addresses whether or not a remedy willmeet all the applicable or relevant and appropriate requirementsof other environmental statues and/or provide grounds forinvoking a waiver.

Long-tern Effectiveness and Permanence: - refers to the ability ofa remedy to maintain reliable protection of human health and theenvironment over time, once cleanup goals have been met.

Reduction of Toxicity. Mobility, or Vo uje, through Treatment —refers to the anticipated performance of the treatmenttechnologies that aay be employed in a remedy.Short-tern Effectiveness - refer* to the period of time neededto achieve protection, and any adverse impacts on human healthand the environment that may be posed during the construction andimplementation period until cleanup goals are achieved.

laolementability - describes the technical and administrativefeasibility of a remedy, including the availability of materialsand services needed to implement the chosen solution.

Cost - includes the capital for materials, equipment, etc. andthe operation and maintenance cost.Support Agency Acceptance - indicates whether, based on itsreview of the; RI,FS and £he Proposed Plan, the State concurswith, opposes, or has no comment on the preferred alternative.

Acceptance - will be assessed in the Record of Decisionfollowing a review of the public comments received on the RI, FS,and the Proposed Plan.

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Analysis of Preferred Alternative

Overall Protection of Human Health and the Environment

Due to contaminant migration and contaminant concentrations thatexceed health-based levels, alternatives 1 and GW-2 would not beprotective of human health or the environment. Since protectionof human health and the environment is a threshold criteria forany Superfund action, these alternatives cannot be selected andthus will not be evaluated further.

Alternative GW-1 would continue to recover and treat thecontaminated groundwater utilizing the existing recovery andtreatment system. This alternative would provide limitedprotection. Alternatives GW-3, GW-4, and GW-5 minimize off-sitemigration of contaminants in ground water flowing beneath theplant. These alternatives would provide adequate protection bycontrolling and reducing risk through a combination ofcontainment, treatment and institutional controls. The preferredalternative would contain and treat the contaminated ground wateron-site while the off-site ground water plume is recovered andtreated through the existing ground water treatment system. Thisalternative would also provide for additional off-sitegroundwater recovery and treatment. The effluent limits for thedischarge of treated ground water would be met for alternativesGW-3, GW-4, and GW-5.

Compliance with ARARs

The goal of the ground water remediation is to achieve backgroundground water quality as required by the PADER. Alternatives GW-1 would probably not achieve the Pennsylvania ARAR for groundwater in a reasonable time period. Alternative GW-3, GW-4, andGW-5 are most likely to achieve compliance with ARARs whichinclude the Safe Drinking Water Act, Clean Streams Act and theClean Air Act. Alternative GW-5 may achieve compliance withARARs more quickly than alternatives GW-3 and GW-4.

Short-term Effectiveness

Alternative GW-1 consists of pumping and treating ground water.This alternative would utilize the existing groundwater recoveryand treatment system. The time for remediation for thisalternative is not known but is expected to exceed that requiredfor alternatives GW-3, GW-4 and GW-5. Short-term risks would beassociated with the construction of the ground water treatmentfacilities and the installation of additional ground waterrecovery wells.

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Long—Term Effectiveness

For each of the alternatives, long-term management will berequired, including monitoring of the effectiveness of therecovery and treatment system. During operation of the treatmentsystem, monitoring of surface water, ground water, and treatedeffluent will be required. The potential for contaminants toexist as a separate, denser phase in the deep aquifer willrequire that ground water recovery be conducted for a prolongedperiod, and can be evaluated at each of the five-yeareffectiveness reviews.

Reduction of Toxicity, Mobility or Volx

Alternative GW-1 provides little reduction of toxicity, mobilityand volume as it does not contain the contamination on-site.This allows only for the existing volume of contaminated groundwater with its inherent toxicity, mobility and volume to becollected and treated. Alternative GW-5 is expected to providethe highest degree of toxicity, mobility or volume reductionbecause of the additional reduction in VOC levels in the aquiferby bioremediation. The groundwater treatment systems inAlternatives GW-3 and GW-4 are anticipated to provide fairlyequal reduction in VOC levels as compared to alternative GW-5.

Implementability

Implementation of alternative GW-5 presents potential obstaclesrelative to technical feasibility. This alternative requires asubstantial degree of permitting, and bioremediation is andinnovative technology with associated uncertainties forreliability, ease of adding additional remedial measures, andconstruction/operation. Potential problems associated withAlternatives GW-3 and GW-4 are not expected to be significant.Alternative GW-4 only requires one permit and is a less widelyused method. Alternative GW-3 will require additional permitsbut is expected to be the most reliable of the treatment systemsconsidered.

Cost

Alternative GW-3 provides the most favorable costs (relative toAlternatives GW-4 and GW-5) and provides essentially equalbenefits relative to Alternative GW-4 and somewhat lesserbenefits than Alternative GW-5, which costs substantially more.

State Acceptance

At this time the PADER is in agreement with EPA regarding theselection of GW-3 as the preferred alternative.

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Community Acceptance

Community acceptance of the preferred alternative will beevaluated after the public comment period, and will be describedin the Record of Decision (ROD) for the site.

Rationale for Selection of the Preferred Alterative

The rationale for selection of the preferred alternative is basedon three principles and is supported by the comparative analysisof the alternatives set forth above. The three principles usedto select the remedy are as follows:

1) The placement of ground water recovery wells along thedowngradient side of the site will prevent further off-sitemigration of the contaminated ground water.

2) The treatment of the recovered on-site contaminated groundwater will help in restoring the quality of on-site ground waterin the overburden and bedrock.

3) The additional recovery and treatment of the contaminated off-site ground water will help in restoring the quality of off-siteground water in the overburden and bedrock .

Based on information currently available, the preferredalternative provides the best balance of tradeoffs among theother alternatives with respect to the evaluation criteria.

Public Participation

EPA relies on public input so that the remedy selected for eachSuperfund site meets the needs and concerns of the localcommunity. To assure that the community's concerns are beingaddressed, a public comment period on this Proposed Plan will beopen on April 17, 1991 and close on May 16, 1991. During thistime, the public is encouraged to submit comments on the ProposedPlan to EPA. A public meeting to discuss the Proposed Plan willbe held on May 2, 1991 at 7:00 P.M. at the Sheraton Hotel inWilliamsport. If you have any questions about the publicmeeting, contact Amy Barnett or Eugene Dennis at the addresses ortelephone numbers listed below. EPA may modify the preferredalternative; select another response action presented in thisplan; or develop another alternative, if public response warrantssuch an action, or if new material is presented. The remedyselected will be documented in a Record of Decision thatsummarized EPA's decision-making process.

Persons interested in reviewing the Plan and related documents inthe Administrative Record will find this information at a

repository located at the James V. Brown Library of Williamsport

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and Lycoming County. To comment, interested parties should writeto the following EPA representatives:

Amy Barnett (3EA21)(215) 597-6905Community Relations CoordinatorEnvironmental Protection Agency841 Chestnut BuildingPhiladelphia, Pennsylvania 19107

or

Eugene Dennis (3HW23)(215) 597-8555Remedial Project ManagerEnvironmental Protection Agency841 Chestnut BuildingPhiladelphia, Pennsylvania 19107

All comments submitted must be postmarked by May 16, 1991.

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