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Proposed PlanConrail Rail Yard

Elkhart County, IndianaApril 1991

U.S.EPA AND IDEM PROPOSE A CLEANUP PLAN

This Proposed Plan identifies the alternative preferred by the UnitedStates Environmental Protection Agency (U.S. EPA) and the IndianaDepartment of Environmental Management (IDEM) for ensuring thatresidents in areas near the site, who are potentially at risk from thegroundwater contamination emanating from the Conrail Superfund site inElkhart, Indiana, are provided with a permanent safe drinking watersupply, and for implementing interim measures to control groundwatercontamination. This plan summarizes other alternatives being consideredfor cleaning up this site.

U.S. EPA and IDEM are issuing this Proposed Plan as part of their publicparticipation responsibilities under the Comprehensive EnvironmentalResponse, Compensation, and Liability Act (CERCLA), also known asSuperfund. This document summarizes information that can be found ingreater detail in the report, "Preliminary Evaluation of Phase 1Remedial Investigation (RI) Results and Interim Remedial Alternatives,April 1990," and the April 1991 Phased Feasibility Study (PFS) report,as well as other documents contained in the Administrative Record filefor this site. The administrative record and other documents describinginvestigations and studies that have been carried out concerning thesite are located in the local repository at the Elkhart Public Library,Reference Desk, 300 S. Second Street, Elkhart, Indiana, and in theoffices of U.S. EPA, Region 5, 230 S. Dearborn Street, Chicago,Illinois. The public is encouraged to review the documents in therepository in order to gain a more comprehensive understanding of thesite and the Superfund activities that have been conducted there.

U.S. EPA, in consultation with IDEM, will select a remedy for the watersupply only after the public comment period has ended and theinformation submitted during that time has been reviewed and considered.When this selection is made, the preferred alternative may be modifiedor another response action presented in this Proposed Plan and in thereport for the FS may be selected based upon new information or publiccomments. Therefore, the public is encouraged to review and comment onall the alternatives identified here for the Conrail Railyard site, soU.S. EPA can select a final remedy that takes into account concernsraised by the public.

SITE BACKGROUND

The Conrail study area is partially located within the southwestern citylimits of Elkhart, Indiana. The remainder of the study area extendsbeyond city boundaries to the west. The study area for the projectencompasses the 675-acre Elkhart Yard of consolidated Rail Corporation(Conrail), and residential areas south of the St. Joseph River, withinwhich groundwater contamination has been identified based on analyticaldata from previous sampling efforts.

Areas of contamination extend from within the Conrail Railyard in twodirections, northwest and north, into residential areas, designated asthe County Road 1 area, the LaRue Street area, the Vistula Avenue area,and the Charles Avenue area (see Figure l). Contaminants detected insamples collected from private wells in these areas, include carbontetrachloride (CC14) , trichlorethylene (TCE), and other volatile organiccompounds (VOCs).

Based upon sampling performed by U.S. EPA/Technical Assistance Team(TAT) in 1986, bottled water was provided to residents whose wells wereaffected by the contamination. Either carbon filter units or water mainconnections were later installed in these residences to ensure a safedrinking water supply. Two types of activated carbon filter units wereinstalled in residences: point-of-use units and whole-house units. Inall, 20 point-of-use and 56 whole-house units were installed. Althoughhomeowners are ultimately responsible for the operation and maintenanceof these units, the Indiana Department of Environmental Management(IDEM) is currently assisting in their operation and maintenance.

EPA/TAT also conducted an inspection of the Conrail site in July andAugust 1986. Seven water/liquid samples and 21 soil samples werecollected at the Conrail site on July 31 and August 1, 1986. Theresults of the analyses revealed TCE concentrations as high as 5,850parts per billion (ppb) and CC14 concentrations as high as 117 ppb insoil samples. Based on these results, the downgradient location of TCE-and CCl4-contaminated private wells from the railyard, and the historyof poor waste handling practices at the railyard, the Conrail site wasplaced on a roster of sites proposed for inclusion on the NationalPriorities List (NPL) in June 1988.

The first phase of the remedial investigation (RI) was essentiallycompleted in January 1990, and was detailed in the April 1990Preliminary Evaluation Report, as well as being summarized in a June1990 fact sheet. During the RI various investigations were undertaken,including a soil gas survey, the collection of soil samples from 29 soilboring locations, for chemical/physical tests, the collection ofsediment samples from 5 locations, the installation of 36 monitoringwells, and subsequent sampling of groundwater from these wells. Inaddition to the above activities, tests were performed at the monitoringwells to aid in determining groundwater flow conditions. The results ofthese investigations are discussed below.

The soil gas survey was conducted primarily in the suspected contaminantsource areas within the Conrail railyard, although a limited number oftests were conducted in the residential/industrial area north of theConrail railyard. This survey was used to preliminarily identify thepresence of contaminants in the soil, and as a screening tool to directfuture sampling efforts. All samples were analyzed for only TCE andCC14. The results indicated that TCE contamination exists in thesubsurface soil in the area noted as the East Leaking Tank Car ParkingArea of the Conrail Yard, to the west of Oakland Avenue. The soil gas

survey did not indicate the existence of TCE or CC14 contamination at anyof the other suspected source locations. The survey, however, didindicate CC14 contamination near the Elkhart Office Machine building onRoute 33, and at a single location along Tower Road, which coincideswith the location of the County Road 1 contamination plume.

Soil samples were collected from borings near the suspected source areaswithin the Conrail railyard, and from areas upgradient from the Conrailrailyard. Analysis of soil samples from these borings confirmed the TCEcontamination noted during the soil gas study in the East Leaking TankCar Parking Area, with concentrations of 36 to 180 ppb found. Throughthis limited sampling, no TCE or CC14 contamination was detected in anyof the other suspected source areas within the Conrail railyard and thearea sampled downgradient of the Conrail railyard.

The results of the groundwater sampling performed under this phase ofthe RI field investigations confirmed the TCE and CC14 contaminationplumes previously identified by EPA, and provided a preliminaryindication of the vertical extent of the plume. TCE in the shallowwells within the County Road 1 area was found in concentrations as highas 96 ppb, while concentrations in the deep wells went as high as atleast 2,300 ppb. No TCE was found in the shallow monitoring wells inthe Vistula Ave. area, and only 1 ppb was found in one of the deepmonitoring wells. Of the shallow and deep wells located around theLaRue Street area, TCE was found in only one shallow well at aconcentration of 6 ppb. TCE was also found in two shallow wellsconstructed near the car shop (in the Conrail Yard) at concentrations of2 and 6.7 ppb. With the exception of a concentration of 7 ppb of TCEfound in one shallow well just upgradient of the Conrail Yard, no otherconcentrations of TCE were detected in any of the other upgradientwells.

In terms of the groundwater sampling, CC14 in the shallow wells withinthe County Road 1 area was found in concentrations as high as 150 ppb,and as high as 150 ppb in the deep wells. CC14 was found in the shallowwells of the Vistula Avenue area in concentrations as high as 340 ppb,and in the deep wells in concentrations as high as 160 ppb. No CC14 wasfound in either the shallow or deep monitoring wells constructed in theLa Rue Street area. CC14 was found in two shallow monitoring wellsinstalled near the Car Shop and to the east of the Car Shop (on theConrail Yard), at concentrations of 230 and 34 ppb, respectively. NoCC14 was found in any of the monitoring wells installed upgradient of theConrail Yard.

The first phase of field investigations for the RI also found that thegroundwater flow directions in both the shallow and deep zones,monitored through this phase of the investigation, were in a north tonorthwesterly direction toward the St. Joseph River and Baugo Bay. Inaddition, it was also found through the investigations that the 16- to20-foot thick clay layer, which was thought to exist over much of thestudy area at a depth of 40 to 60 feet below grade, was not continuous

across the study area. Soil borings indicate that the clay layerseparating the shallow and deep zones was not present in the County Road1 area and in an area immediately south of LaRue Street. Where a claylayer was found to exist, the depth to the clay layer varied from 3 to36 feet below ground surface and its thickness was found to range from1 to 85 feet. It was noted through these investigations that theidentified contamination plume in the County Road 1 area generallycoincides with the area where no clay was found, and that the plumecoincides with the shallow and deep groundwater flow direction.

SCOPE AND ROLE OF THE INTERIM REMEDIAL ACTION

The scope of this interim remedial action is to provide a clean watersupply to residences affected by risks in and around the site and tocontrol groundwater contamination and expansion of the groundwaterplume. Investigations have not provided sufficient information to allowthe initiation of the complete remedial action at this point in time.Specifically, more investigations are necessary to identify the sourceareas within the Conrail railyard, as well as any other source(s) off-site of the Conrail railyard, which are contributing to the TCE/CC14contamination plumes. Secondly, more investigations are needed tofurther determine the vertical extent of the contamination plumes, bothwithin and off the Conrail railyard, including each of the previouslydesignated residential areas (i.e., County Road 1, LaRue Street, VistulaAvenue, and Charles Avenue). A decision on restoration of thegroundwater will be postponed until these additional investigations arecomplete. Finally, investigations are needed to further define the linkbetween the County Road 1 contamination area, and the contaminationfound in the Vistula Avenue and Charles Avenue areas.

Information has pointed to the need for an interim remedial action toprovide a clean water supply to residences affected by potential risksin and around the site, and to control the migration of groundwatercontamination in the study area. Specifically, there is a need toinstitute an interim remedial action that will eliminate or reduce thehealth risk posed to humans by exposure to contaminated groundwater.This need is based on contaminant levels present in the potable watersupply for some of the residences, and the potential for otherresidences in the area to be impacted by the contaminated groundwater,due to movement of the contaminated groundwater. The interim action isnecessary or appropriate to prevent further groundwater degradation andto reduce threats to human health and the environment. The interimaction will be monitored and maintained to ensure its effectivenessuntil the final remedy is implemented.

The interim action will be consistent with the final remedy. Even ifaquifer cleanup actions can be initiated within a few years, it willtake several years to ensure that risks associated with exposure to thegroundwater will be eliminated. Therefore, addressing exposure to thegroundwater at this time, through the provision of a potable watersupply, is a necessary and natural part of the overall remedy. This

interim action will not exacerbate the site problem; rather, thegroundwater containment actions identified by this interim action willbe an integral part of the final groundwater remedy.

SUMMARY OF SITE RISKS

As a part of the feasibility study for this interim action, apreliminary risk assessment was prepared to evaluate the need forimplementation of an interim remedial measure designed to immediatelyreduce or eliminate public exposure to contaminated groundwater. Manyresidences in the area rely on this groundwater as their domestic watersupply source. Residents using the groundwater can be exposed to thecontaminants it contains. The most significant exposures generallyresult from direct consumption of the water itself and beverages madewith the water, and through dermal contact with the water and inhalationof vapors from the water while bathing.

U.S. EPA calculated an unacceptable public health risk for exposure tothe contaminants of concern (i.e., TCE and CCl4} based on the exposurerequired for one additional person in a million to contact cancer ifexposed to TCE or CCl4 over a lifetime. (Note: These risks are inaddition to normal risk of cancer posed in everyday life.) For a one ina million lifetime health risk, U.S. EPA determined that if anindividual is exposed to greater than 1.23 ppb of TCE or 0.152 ppb ofCC14, then that person would be at risk of contacting cancer.

Also, another standard developed by U.S. EPAfs Office of Drinking Waterwas utilized, specifically the National Primary Drinking Water Standardsmaximum contaminant levels (MCLs) for certain substances in drinkingwater. These standards are set at levels as close to the level at whichno known or anticipated adverse health effects would occur, allowing anadequate margin of safety, as can be feasibly achieved using bestavailable technology. For both TCE and CC14, the MCL is 5 ppb.

As can be seen from the above figures, if residents with point of entryfilters were to drink untreated water or if they used untreated waterfor regular household purposes such as showering, they could be exposedto contaminant levels much higher than the estimated baseline risklevels, and the MCLs. In addition, the residents within the impactedarea who are using private well supplies not equipped with filtersystems as their sole source of potable water are potentially at risk.The basis for this determination is that stage fluctuations in the St.Joseph River, make the groundwater flow regimes susceptible to changes,which may result in the mixing of groundwater and further expansion ofthe currently identified boundaries of contamination. In addition, thecurrent monitoring program and supply of filtration units arerestricted. Finally, IDEM's monitoring program indicates thatgroundwater contamination levels are increasing in some of theresidential wells in the County Road 1 and Vistula Avenue areas.Therefore, there are four general areas which are considered to be

potentially at risk based on the above scenario: the County Road 1,Vistula Ave., Charles Ave., and LaRue St. areas. There are a total ofapproximately 500 residences which would be affected in these areas.

Releases of hazardous substances from the site, through exposure to thegroundwater, if not addressed by the preferred alternative or one of theother measures discussed in this plan, may present an imminent andsubstantial endangerment to public health, welfare, and the environment.

SUMMARY OF ALTERNATIVES

Alternative l: No Action

The Superfund program requires that the "no action" alternative beevaluated at every site to establish a baseline for comparison. Undera no-action alternative, actions taken to reduce the potential forexposure should not be included as a component of the alternative. Assuch, this alternative would evaluate the situation at the site withnone of the residences having individual carbon filter units. The no-action alternative serves as a baseline for comparison of otheralternatives.

Taking no action at the site would result in leaving contaminatedgroundwater in the aquifer, and would increase exposure to thecontaminated groundwater, since operation and maintenance of theexisting filter systems could not be guaranteed.

The no-action alternative would, however, include the monitoring of thegroundwater contamination, to monitor risks resulting from the no-actionalternative. It is assumed that the monitoring program will consist ofthe semiannual sampling of twenty five wells installed during the RI.

Total Present Worth Cost: $147,300

Alternative 2: Groundwater Monitoring; Installation of a New centralWell Supply in Contaminated Area with Water Distribution System for theFour Potentially at Risk Areas; Groundwater Extraction, Treatment, andDisposal to Surface Waters

This alternative includes the installation of four groundwaterextraction wells within the area of contamination, three of which wouldbe placed along the centerline of the plume within the County Road 1area, and one approximately in the center of the Vistula Ave. areacontamination. This system will be designed to initially withdrawapproximately 500 gallons per minute (GPM) of groundwater. Airstripping will be utilized to treat the contaminated groundwater, withsuch a treatment facility located in the Vistula Ave. contaminationarea. The treatment will actually consist of four primary components:(1) an influent storage tank; (2) a pretreatment system; (3) an airstripping system; and (4) a treated water (effluent) storage tank.

This alternative will serve two purposes, to control the movement of the

plume, and to serve as the potable water supply source for the affectedresidences. Groundwater extraction rates will be designed, and adjustedas necessary to provide for adequate control of the movement of thegroundwater contamination. In addition, the extracted groundwater willbe treated to levels necessary to allow it to be used as the source ofdrinking water for the residences.

This alternative will also include a water distribution system whichwill be sized to convey both the fire flow demand and the peak hourlypotable demand. The system will be designed to serve approximately 505units, within the four areas, and will include the installation of about67,000 feet of distribution line.

Treated water in excess of domestic requirements will be discharged tothe St. Joseph River. This alternative also includes groundwatermonitoring, as discussed under Alternative 1.

Total Present Worth Cost: $5,123,600

Alternative 3: Groundwater Monitoring; Installation of IndividualPoint-of-Entry Treatment Units; Groundwater Extraction, Treatment andDisposal of Treated Water

This alternative includes the groundwater extraction and treatmentsystem detailed in Alternative 2. However, under this alternative, allof the groundwater that is extracted and treated will be discharged tothe St. Joseph River.

This alternative entails the installation of point-of-entry (POE) carbonfilter units in homes and businesses in the affected or potentiallyaffected area. For this alternative, about 450 homes or businesses notcurrently using POE systems, including those currently having point-of-use systems will be provided with POE systems. Periodic sampling, aswell as filter, prefilter, and flow meter replacement, will also benecessary under this alternative. This alternative is similar toAlternative 1, in that it includes groundwater monitoring.

Total Present Worth Cost: $4,450,900

Alternative 4: Groundwater Monitoring; Provision of Separate WaterSupplies for the Charles Ave./Vistula Ave. area, and the County Road1/LaRue street area; and Groundwater Extraction, Treatment/ and Disposalof Treated Water

This alternative includes the groundwater extraction and treatmentsystem detailed in Alternative 2.

Under this alternative, the source of the potable water supply for theaffected residents is dependent upon the County in which the area islocated. In the County Road 1 and LaRue Street areas (which are bothlocated in Elkhart County), the installation of a water distributionsystem would extend from the existing City of Elkhart water supply

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system. Such a distribution system would service about 304 units, andwould entail the installation of approximately 43,000 feet ofdistribution line.

For the Vistula Ave. and Charles Ave. areas (which are both located inSt. Joseph County), this alternative includes two options. The firstoption, is to connect the approximately 201 residences in these areas toa municipal water supply being planned for the Town of Osceola. Thereare uncertainties involved, however, both in terms of whether such asystem will actually be developed, and the timing involved in thedevelopment of such a system. Therefore, another option for servicingthis area, involves the use of treated groundwater from the proposedgroundwater extraction system. Under both of these options, around20,000 feet of distribution lines will need to be installed. Inaddition, any treated groundwater, in excess of domestic requirementswill be discharged to the St. Joseph River. This alternative is similarto the previous alternatives, in that it includes groundwatermonitoring.

Total Present Worth Cost: $4,613,600

Alternative 5: Groundwater Monitoring; Provision for Extension of thecity of Elkhart's Municipal Waterworks to Serve all Four Affected Areas;and Groundwater Extraction, Treatment/ and Disposal of Treated Water

This alternative is similar to Alternatives 2, 3 and 4, in that itincludes groundwater monitoring to help ensure that this alternative iseffectively meeting the remedial action goals. In addition, thisalternative also includes the groundwater extraction system detailed inAlternative 2. Under this alternative, all of the groundwater that isextracted and treated will be discharged to the St. Joseph River.

The potable water supply under this alternative would serve all four ofthe affected areas, through the installation of a water distributionsystem extending from the existing City of Elkhart water supply system.Such a distribution system would service all 505 of the estimated unitsin the affected areas, and would entail the installation ofapproximately 67,000 feet of distribution line.

Total Present Worth Cost: $3,969,300

THE PREFERRED ALTERNATIVE

The preferred alternative is Alternative 5. This alternative includesthe tie-in of all four of the affected areas to the existing City ofElkhart municipal water supply system. This alternative also includesgroundwater monitoring, and the installation of a groundwaterextraction, treatment, and disposal system. Finally, this alternativewould include some type of instutional controls, such as deedrestrictions limiting residential contact with the groundwater, as wellas the plugging and abandonment of wells at those residences connectedto the system.

Implementation of this alternative, however, is dependent upon thecapability of the City of Elkhart's system to serve this entire area,and is dependent upon the City of Elkhart having the ability/authorityto serve those areas outside of Elkhart County.

In the event that extending City of Elkhart service to the affectedareas within St. Joseph County, proves to be unfeasible, the preferredalternative would be Alternative 4. This alternative is similar toAlternative 5 in all respects, except that the supply of potable waterto affected residents will be handled separately for each County. Forthe affected residents in Elkhart County (i.e., those in the County Road1 and LaRue Street areas), potable water will be supplied through a tie-in to the City of Elkhart municipal water supply system. For theaffected residents in St. Joseph County (i.e., those in the Vistula Ave.and Charles Ave. areas), potable water will be supplied through eithera tie-in to the proposed Town of Osceola water system, or with extractedgroundwater, which has been treated.

EVALUATION OF ALTERNATIVES

The National Contingency Plan (NCP) requires that the alternatives beevaluated on the basis of the following nine evaluation criteria: (1)Overall protection of human health and the environment; (2) Compliancewith applicable or relevant and appropriate requirements (ARARs); (3)Long-term effectiveness and permanence; (4) Reduction of toxicity,mobility, or volume through treatment; (5) Short-term effectiveness; (6)Implementability; (7) Cost; (8) State acceptance; and (9) Communityacceptance. This section discusses how the preferred alternativecompares to the other alternatives with regard to these nine evaluationcriteria.

1. Overall Protection of Human Health and the Environment

With the exception of the no-action alternative, all of the alternativesprovide good protection of human health and the environment with respectto exposure to contaminated groundwater. The no-action alternativeprovides no such protection. Alternatives 5 provides a somewhat higherdegree of protection than Alternatives 2 and 3, since Alternative 5eliminates the exposure to the affected residences, through connectionto a different water supply source. Alternatives 2 and 3 do providegood protection, however, since the extracted groundwater will betreated to at least MCLs. The level of protection provided byAlternative 4 will depend upon the option selected for providing potablewater to the affected areas of St. Joseph County. If a tie-in to theTown of Osceola is possible, the level of protection will be comparableto Alternative 5. If, however, the extracted, treated groundwater is tobe used as the water supply for the affected areas of St. Joseph County,the level of protection afforded by Alternative 4 will be comparable tothat provided under Alternatives 2 and 3.

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2. Compliance with ARARs

All of the Alternatives should be able to meet the identified ARARs atthe point of exposure. In light of the limited purpose of the remedy,clean up standards for groundwater in the aquifer do not pertain to theremedy and thus are not ARARs for this interim remedy. Aquifer cleanupARARs will be determined and addressed by a later measure when adecision is made on cleanup of the groundwater. Thus the ARARs thatpertain to this groundwater action are mainly those that relate todrinking water (i.e., MCLs), and treatment and discharge of theextracted groundwater.

3. Long-Term Effectiveness and Permanence

Alternative 5 will provide the highest degree of long-term effectivenessand permanence since it involves the provision of a water supply from asource other than the contaminated groundwater at the site. This degreemay not be much higher, however, since groundwater from the City ofElkhart's Main Street Well Field (which would probably be the source ofwater for this area) is also contaminated with TCE, although it istreated through the use of air strippers. The long-term effectivenessand permanence of Alternative 4 will depend upon the option chosen forservicing of the St. Joseph County area. If this area ties in to theTown of Osceola, then the degree of permanence for Alternative 4 will bethe same as that for Alternative 5. If, however, treated groundwater isutilized as the source of the drinking water for the St. Joseph Countyareas, the long-term effectiveness and permanence will be somewhat lesssince potential changes in contaminant concentrations could effect theeffectiveness of the treatment system, and thereby potentially effectthe permanence of Alternative 4. As with Alternative 4, sinceAlternative 2 involves the provision of treated groundwater to affectedresidences, long-term effectiveness and permanence although still beingadequate, is not as good as Alternatives 4 and 5. Alternative 3provides a below average degree of long-term effectiveness andpermanence, partly because of the potential for changes in thecontaminant concentrations to impact the effectiveness of the filters,and because these changes could impact each of the 505 filtersdifferently. Finally, the no-action alternative has no long-termeffectiveness, since it will not reliably protect human health and theenvironment.

4. Reduction of Toxicity, Mobility, or Volume Through Treatment

Since Alternatives 2, 3, 4, and 5 all include groundwater extraction,treatment, and disposal, they all provide for at least an adequatereduction of toxicity, mobility, and/or volume of the groundwatercontamination. Specifically, all of the alternatives result in thereduction of toxicity in the extracted groundwater, through treatmentfor VOCs using air stripping. Mobility of the groundwater contaminationwill be reduced through control of the groundwater extraction (e.g., therate of extraction, the location of the extraction wells, etc.) . Volumewill also be reduced through the extraction process. Alternatives 2 and

114 may provide a slightly higher degree of reduction, since the extractedgroundwater will be used as the water supply and will hence need to betreated to a potentially higher level.

5. Short-Term Effectiveness

Alternative 3 provides the highest degree of short-term effectiveness,since the home carbon units are readily available, and can be installedmore quickly than a waterworks system. In addition, there will belittle or no adverse effects to human health and the environment duringthe implementation period for Alternative 3. The short-termeffectiveness for Alternatives 2, 4, and 5 will also be good, but willbe lower than that for Alternative 3, since the time period forimplementation of these alternatives will be longer, and will result insome disruption during the period of construction. Alternative 5 willprovide a somewhat higher degree of short-term effectiveness (overAlternatives 2 and 4), if connection to the City of Elkhart's system canbe agreed to quickly.

6. Implementability

Alternative 3 will be the easiest to implement, since the filters areeasily available, can be easily and quickly installed, and will simplyrequire agreement by the individual homeowners to begin implementation.The implementability of Alternative 5 is good in terms of technicalfeasibility, since it involves materials and services which are readilyavailable. The administrative feasibility of Alternative 5, however,will hinge on the City of Elkart having the jurisdictionalability/authority to serve those areas outside of Elkhart County. Aswith Alternative 5, the implementability of Alternative 4 is also goodin terms of technical feasibility, since it involves materials andservices which are readily available. The administrative feasibilityof Alternative 4 depends upon the availability of connecting to theproposed Town of Osceola water system. Alternative 2 is adequate interms of implementability, being technically feasible in terms ofmaterials and services being readily available. Coordination among theaffected governmental bodies will be essential for most of thesealternatives. In addition, all of the above alternatives will includesome permitting requirements which may affect the administrativefeasibility of the alternatives, such as the discharge of treatedgroundwater, and the use of air strippers.

7. Cost

The costs of the various alternatives are presented above. Alternatives3, 4, and 5 all cost about the same. Alternative 2 is slightly moreexpensive.

8. State Acceptance

The State of Indiana supports the selection of the preferredalternative.

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9. Community Acceptance

Community acceptance of the preferred alternative will be evaluatedafter the public comment period ends and will be described in the Recordof Decision (ROD) that is issued for this remedy.

SUMMARY OF THE PREFERRED ALTERNATIVE

In summary, either Alternative 4 or 5 will substantially reduce the riskassociated with exposure to the contaminated groundwater, through theprovision of an alternate water supply. Both alternatives are believedto provide the best balance with respect to the evaluation criteria.Based on available information, U.S. EPA and IDEM believe the preferredalternatives would protect human health and the environment with respectto exposure to the contaminated groundwater, would comply with ARARs,would be cost effective, and would use permanent solutions andalternative treatment technologies to the maximum extent practical.This current interim action will be followed by a complete measure thatwill attain all ARARs. Because these alternatives would use treatmentfor the groundwater, through air stripping following pretreatment, theywill meet the statutory preference for a remedy that poses mainly arelatively low long-term threat to human health and the environment, andthat involves treatment as a principal element.

ROLE OF THE COMMUNITY IN THE PROCESS

U.S. EPA and IDEM encourage the public to comment on all of the remedialalternatives discussed in this proposed plan as well as the preferredalternative for the Conrail Site. These comments will be evaluatedbefore a final remedy is selected for the site. For a completedescription of the investigation and the alternatives underconsideration for the site, interested parties can review the documentsavailable in the following information repositories:

Elkhart Public LibraryReference Desk300 S. Second StreetElkhart, IN 46516

Harley Holben Elementary School30046 County Road 16 WElkhart, IN 46516

The administrative record, which contains all of the documents that U.S.EPA will use to select the final remedy for the site, is located at theElkhart Public Library site.

Written comments will be accepted during a public comment period beingheld from April 19, 1991 to May 20, 1991. Members of the community areencouraged to attend a public meeting on May 1, 1991 at the HarleyHolben Elementary School Gymnasium to discuss the proposed alternativesfor remediating contamination at the site. Verbal comments will berecorded during the meeting.

GLOSSARY

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Administrative Record - A compilation of documents that U.S. EPA eitherconsidered or relied upon in selecting remedial or removal actions to betaken at a Superfund site.

Air Stripping - A technology used to remove contaminants fromgorundwater. Air stripping involves pumping contaminated water to thetop of a tower. As the water cascades down, high powered fans send airupward causing volatile organic compounds to volatilize (i.e., changefrom liquid to gas). The volatilized contaminants are treated, ifnecessary, and then released into the atmosphere.

Applicable or Relevant and Appropriate Requirements (ARARs) - Federal,State, and local environmental and public health laws with whichremedial action alternatives must comply.

Aquifer - An underground rock or soil formation capable of yieldingwater in quantities suitable for domestic, industrial, or agriculturalpurposes.

Carbon Tetrachloride (CC14) - A nonflammable volatile organic compoundused as a solvent for oils, fats, and coatings, as a component in themanufacture of Freon (TM) and other chemicals, and, at one time, as afire suppressant in fire extinguishers. Carbon tetrachloride is a knowncarcinogen. The drinking water standard determined by the U.S. EPA forCC14 is 5ppb.

Comprehensive Environmental Response, Compensation and Liability Act of1980 (CERCLA) - A Federal law passed in 1980 and revised in 1986 by theSuperfund Amendments and Reauthorization Act. CERCLA created a specialtax that goes into a trust fund, commonly known as "Superfund," toinvestigate and clean up abandoned or uncontrolled hazardous wastesites.

Extraction Well - A pumping well designed to draw contaminatedgroundwater from an aquifer.

Maximum Contaminant Levels (MCL) - Enforceable federal standards for themaximum permissable level of contaminants in drinking water. MCLs areset as close to the Maximum Contaminant Level Goals as feasible.

National Contingency Plan (NCP) - The Federal regulation that sets theframework for the Superfund program. The NCP identifies thegovernmental organizations involved in remedial response, outlines theirroles and responsibilities, and discusses the interrelationships ofthese organizations. In addition, the NCP provides guidelines forplanning and conducting response activities.

National Priority List (NPL) - An EPA list of top priority hazardouswaste sites in the U.S. that are eligible for investigation and cleanupunder the Superfund program.

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Parts per billion (ppb) - A part per billion is a description of howmany units of a chemical that are present per billion total units. Forexample, 1 second in 32 years or one drop in a 10,000 gallon tank,equals one part per billion.

Phased Feasibility Study - An evaluation of remedies that are designedto address one part of the overall contamination problem. Phasedfeasibility studies may be conducted as a supplement to the morecomprehensive Remedial Investigation and Feasibility Study and mustpropose remedies that will be cons istent with a f inal remedy to theoverall contamination problem.

Present Net Worth (PNff) - An economic term used to describe today's costfor a Superfund cleanup and reflect the discounted value of futurecosts. A present worth cost estimate includes construction and futureoperation and maintenance costs. U.S. EPA uses present net worth valueswhen calculating the cost of alternatives for the long-term projects.

Record of Decision (ROD) - A document issued by U.S. EPA that describesthe corrective action to be taken at a Superfund site. The correctiveaction is selected after public comments on the proposed plan areconsidered.

Remedial Investigation (RI) - The remedial investigation examines thenature and extent of contamination problems at the site.

Soil Gas Survey - An analysis of air /gas samples drawn from thesubsurface to determine whether volatile organic compounds are present.

Superfund - A trust fund created under the Comprehensive EnvironmentalResponse, Compensation, and Liability Act of 1980 (CERCLA) toinvestigate and clean up abandoned or uncontrolled hazardous wastesites.

Trichloroethylene (TCE) - A nonflammable volatile organic compound usedas a solvent in dry cleaning processes, in removing oil and grease frommetal parts, and in removing caffeine from coffee. TCE is also used inthe manufacture of many other chemicals, pesticides, coatings, etc. TCEis a potential carcinogen in humans. The drinking water standarddetermined by the EPA for TCE is 5ppb.

Volatile Organic Compounds (VOCs) - Any of a number of chemicals thatcontain organic carbon and readily evaporate from liquids to gases whenexposed to air. Because of this tendency to evaporate in air, VOCsdisappear more rapidly from surface water than groundwater. Becausegroundwater does not usually come in contact with air, VOCs are noteasily released and can be present in drinking water. VOCs may pose athreat to human health. Some VOCs are believed to cause cancer inhumans. Examples of VOCs include trichloroethylene (TCE), carbontetrachloride (CC14) , xylene, and toluene.