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Environmental Protection Agency - Region 3Superfund Program

REVISED PROPOSED REMEDIAL ACTION PLAN

HH Burn Pit Superfund SiteFarringtqn, Virginia December, 1994

I. INTRODUCTION

The Proposed Remedial Action Plan and theRevised Proposed Remedial Action Plan

The U.S. Environmental Protection Agency, Region ITI ("EPA")has prepared this Revised Proposed Remedial Action Plan to complywith Section 117 of-the. Comprehensive Environmental Response,Compensation, and Liability Act of 1980, as amended ("CERCLA"),42 U.S.C, § 9617, and to describe EPA's preferred remedial actionfor the HH Burn Pit Superfund Site located in Farrington, HanoverCounty, Virginia ("Site").

EPA initially issued" a Proposed Remedial Action Plan("PRAP") for the Site on December -21, 1993. The_PRAP highlightedkey information from the Remedial. Investigation/Feasibility Study("RI/FS") performed for; the Site, described remedial alternativesthat were evaluated by EEA, identified EPA's preferred remedialalternative, and provided information supporting this preference.The preferred remedy "presented in the December 1993 PRAP includedexcavation and off-site.-disposal of contaminated soil andsediments, and extraction and treatment of contaminated groundwater";" : ~ ".—-—: :- - - - - - :- - - - • • -

A thirty day public comment period began on December 21,19.93 and ran through January 19, 1994. In response to a requestfrom the public, EPA extended the comment period an additionalthirty days through...February 18, 1994. -A public meeting was heldby EPA during the comment p_eriod, on January 11, 1994. Duringthe public comment period, EPA received one letter from aresident, as well as"two documents containing comments from agroup of companies .and 'individuals associated with the Site.These letters., along with the transcript from the public meeting,have been placed in "the Administrative Record file for the Site.

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During preparation of the Record of Decision ("ROD"), EPAidentified an issue that had the potential to significantlyimpact the cost of EPA's preferred alternative. Commentors hadquestioned EPA's preference to dispose of contaminated soils fromthe Site in a Virginia sanitary or industrial landfill regulatedunder Subtitle D of the Resource Conservation and Recovery Act("RCRA"). In investigating this matter further, EPA determinedthat the soils from" this Site could not be disposed of in thismanner. - - - - .

Contaminants present in Site-soils originated from spentsolvent wastes disposed at the Site. These wastes are regulatedas "F-listed" hazardous waste under RCRA and must be managed ashazardous wastes under that statute and its implementingregulations. RCRA-listed wastes may be disposed of only in ahazardous waste landfill permitted in accordance with RCRASubtitle C. In addition, RCRA-listed waste with contaminantconcentrations exceeding levels established in the RCRA .LandDisposal Restrictions cannot be landfilled without treatment.Treatment standards for "F-listed" wastes such as those found atthe Site are set forth at 40 C.F.R. Part 268, Subpart D (s_ee 59Fed. Keg. 47980, 48046 (September.19, 1994)).

The need to treat the "F-listed" wastes found at the Siteprior to landfilling results in an;.increase in the cleanup costof remedial actions which include this component. Theseincreased costs are reflected in this Revised Proposed RemedialAction Plan.

This Revised Proposed Remedial Action Plan describesremedial actions considered for the Site and EPA/s preferredcourse of action. EPA invites comment on all of the alternativesdescribed in this Revised Proposed.Remedial Action Plan. EPA maymodify the preferred alternative or- select another responseaction presented in this Revised Proposed Remedial Action Planand the Feasibility Study based on new information or publiccomments. Public comments and EPA's responses will be documentedin a Responsiveness Summary that will become part of a Record ofDecision announcing selection of a remedial action for the'Site.

Availability of Supporting Documentsand Opportunity for Public Comment

EPA encourages the public to review and comment on all of. .the alternatives, including the preferred alternative identified -in this Revised Proposed Remedial Action Plan, the RI/FS preparedfor the Site, and other documents contained in the AdministrativeRecord file for the Site. Interested parties may comment duringa public comment period which begins on December 23, 1994 andcloses on January 23, 1995. Written comments must be postmarkedno later than January 23, 1995. All comments submitted duringthe comment period will be reviewed and considered as part of theremedy selection process.

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Persons interested in reviewing the RI/FS and otherdocuments in the Administrative Record file will find thisinformation at the EPA Regipnal Qf£ic^ in Philadelphia and at arepository ..located .as flo.i Lows: ... "'r. : . . . .

Pamunkey Regional .LibraryAshland Branch

102 South Railroad "Ave.Ashland, VA 23005

(804) 798-4072 '

Pamunkey Regional "Library" hours .are Monday through Thursday from10:00 AM - 9:00" PM; Friday and Saturday from 10:00 AM - 6:00 PM.

EPA will be available to answer questions about this RevisedProposed Remedial Action Plan on January 4, 1995 from 2:00 - 7:00p.m. at the village, of.. Farrington Firehall in Glen Alien,Virginia. If anyone would' like the opportunity to present formalcomments during this .session,"please'notify one of the followingrepresentatives, prior to the session so arrangements can be madeto record your comments.

Leanne Nurse (3EA30)Community Involvement FacilitatorEnvironmental- Protection Agency

841 Chestnut StreetPhiladelphia, - Pennsylvania 19107

(800) 553-2509

or

Vance A. Evans (3HW41)Remedial Project Manager.

Environmental Protection Agency841 Chestnut Street

Philadelphia, Pennsylvania 19107(215) 597-8485

II. SITE BACKGROUND

The HH Burn Pit Site is located in Hanover County, Virginia,approximately 12 miles northwest of the city of Richmond onStaples Mill Road (Route 33) and 0;5 mile south of the -communityof Farrington, Virginia :(see Figure 1). The disposal area at theSite is a circular clearing approximately 1 acre in size locatedon a 73.5-acre parcel of"land owned by T. Frank Flippo and Sons,a Virginia limited partnership (see Figures 2 arid 3). Thecircular disposal area is .approximately 260 feet in diameter andis surrounded by a raised berm of native soil approximately 2 to4 feet high.' The berm was created when the disposal area was

cleared in what was originally a wooded area. Presently, only anarrow band of trees. 20 to 50 feet wide surrounds the site'sbermed disposal area and extends along the path of ._anintermittent stream. The stream originates on the bermed areaand flows westward through the Site to another stream, the BlackHaw Branch, approximately 2,800 feet from the bermed area. The"rest of the 73.5-acre property was clearcut in 1990. The .property now consists of low growing bushes and young trees. Thelogging that was performed in 199(1 Joy the current" STte owner hascaused significant disturbance to -the natural drainage andecological balance of the land, much of which is classified as awetland. No structures exist on the property.

Access to the Site is limited to one dirt road, which isapproximately 1,200 feet long and perpendicular to :.~-the west sideof Route 33. ^ A locked cable located at the approximate half-waypoint of the road restricts vehicular site access. No otherbarriers exist that would restrict pedestrian access.

The land surrounding the Site property is primarilywoodlands and farm fields, but an increasing number of .residential homes are being built. Approximately 175 people livewithin 1 mile of the Site. Public roads exist within 1 mile ofthe Site in every direction. The nearest large industry is theTyson Chicken processing plant, which is located approximately2.5 miles southeast of the Site on Route 33. The nearestresidence is approximately 400 feet east of the Site, adjacent, tothe Site access road. _ _. ..: _ . . __.

The regional drainage pattern in the vicinity of the Site isprimarily in a northwest to.southeast orientation. Smallertributaries and other minor surface drainage occur in manydirections and at various angles to the primary drainage.

tfydrogeology

The HH Burn Pit Site lies within the Piedmont Blue RidgeGroundwater Region. This region is characterized by a thickmantle of clay-rich saprolite overlying fractured crystallineigneous and metamorphic bedrock. The Petersburg formation,which is a fractured granite, underlies the Site and is a widelyused local aquifer. Ground water within the granite is stored infracture and joint openings. The Petersburg granite wasencountered at a depth between 63 to 71 feet below ground surfaceat the Site and in its close proximity. The shallow ground waterflow direction in the Petersburg aquifer is generally to thewest-northwest at the Site, following the topography. Directlyoverlying the Petersburg granite is its associated saprolitewhich is approximately 60 to 70 feet thick across the site. Thesaprolite is also used as an aquifer locally. Ground water isstored in the saprolite in the intergranular pore spaces as wellas within any relict structures of its parent rock the Petersburg

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granite..such as fractures.and joints/ The direction of groundwater .flow -in the saprolite aquifer is .generally in the samedirection as the shallow bedrock Petersburg .aquifer to the westand follows the topbgrag.hy , . Residence's surrounding the Siteobtain drinking water .from~~~doinestrc'"wells which produce watereither from the saprolite or the Petersburg granite aquifers.

Site History and Enforcement

The Site was purchased in' 19:50,.by Mr_. Howze Haskell. Fromapproximately I960 to 1976,"""the" Site was. owned and operated bythe Haskell.. "Chemical Company, Inc., which manufactured chemicalsat an off-site plant for distribution to several companies in theRichmond area. - The Site, property was conveyed to the presentowner, T. Frank Flippo:and Sons, in July 1935.

From 19-60'to 1976, the Site Was. used to burn spent solventsfrom printing press cleaning operations and printing ink residuecollected by the Haskell Chemical Company. There is evidencethat substances -from, other commercial operations were burned.Waste Was'.-brought in SB-gallon"drums'and stored on-site in one oftwo major collection" areas". "Tor" disposal/ wastes were emptiedinto one of two pits and burned (see Figure 2). The burn pitsare no longer visible since the disposal area has been regraded.

Operations ceased'in 1976, arid the property was transferredto Mr. Haskell's then newly formed holding.company, HHIncorporated, in 19T7. ; In JUne 1981, HH Incorporated submitted a"Notification of,., Hazardous Waste Site" form (Form 8900-1) to EPAas required, by .CERCLA. \ EPA suspected that hazardous substancescould be present due to possible incomplete combustion of thesolvents and ink residue as well as chemical by-products fromburning. .—- - ~-:——....----- ......—._..—...... .. - ——

The Virginia Department of Health, Division of Solid andHazardous Waste ("VA DSHW"), the agency responsible for hazardouswaste issues prior to the establishment of, the VirginiaDepartment of Waste Management ("VDWM"), initially managedinvestigation activities at the Site. Six residential wells weresampled in November and December 19.81 to determine if there wasevidence of migrating contamination. .The VA DSHW determined thatthe level of organic and inorganic contaminants in theresidential wells did not exceed background levels. In December1981, VA DSHW approved a cleanup plan prepared for the Site by HHIncorporated and which, if implemented, would.remove the sourcesof contamination.-

In May 1982, approximately 1,000" empty drums stored in thetwo collection "areas were reportedly crushed in the bermed areaand transported to a hazardous waste disposal facility under thesupervision of the VA DSHW. Stained soil, including the soilthat lined the burn pit, was also reportedly removed from the

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Site at the same time. Two monitoring wells/"one upgradient andthe other downgradient, were installed at the Site in June 1982.Based on the analytical results of water samples taken from thesewells, no conclusive evidence of groundwater contamination wasfound. Erosion and sediment control was initiated under a permitfrom Hanover County. These measures included grading andstabiliEing soils, -intercepting and channeling runoff to adrainage path, and reseeding and planting.

In response to community concerns, a general health surveywas conducted by the Virginia Department of Health in May 1983.Thirty-five households were surveyed, representing 143individuals. Based on the survey, no conclusive evidence linkinghealth problems to Site contamination was found. -

A non-sampling Preliminary Assessment of the Site wasconducted by EPA on March 16, 1983. On March 27, 1984, EPAperformed a Site Inspection that included samplinef'ofgroundwater, sediments, leachate, and runoff waterT Analyticalresults of these samples revealed the presence of polychlorinatedbiphenyls ("PCBs") as well as solvent components. These results,combined with the knowledge that waste burning had occurred atthe Site, raised concerns that dioxin might be present at theSite. The burning of PCBs is known to create dioxin compounds.The Site Inspection Report was published in October 1985.

On December 3, 1985, a dioxin screening was performed by EPAat the Site. This screening involved, among other things, soiland sediment sampling and analyses for dioxin. Results of theanalyses showed the presence of dioxin and dibenzofuran isomers.On October 9, 1986, a more extensive sampling study was performedthat involved the collection of 19 field samples to be analyzedfor dioxin. Results of the dioxin analyses showed low levels ofdioxin in three of the 19 samples. Other sample resultsrevealed elevated levels of volatile organic compounds ("VOCs"),metals, and PCBs.

In January 1987, the Site was proposed for inclusion on theCERCLA National Priorities List ("NPL11). A RemedialInvestigation and Feasibility Study ("RI/FS") commenced in 1988.Initial fieldwork was performed from November 19-88- through March1989. The Phase I analytical results showed a higher level ofcontamination at the Site than expected and a potential for off-site migration. Contamination beyond the burn pits andcollection areas included volatile organics, PCBs, pesticides,and inorganics (lead, zinc, cadmium, copper, and mercury). Tenresidential drinking water wells were tested; however, nocontamination of drinking water believed to be attributable tothe Site was found. The Site was placed on the NPL in March1989. Phase II of the RI/FS resumed in the Spring of 1992 andwas completed in June 1992.

III. SUMMARY OF._RI DATA AND SITE RISKS

Remedial Investigation Data " . , .^. ~. = ^ ". "O . j|- ^ . W *•

The' Remedial Investigation, ("RI'".) identified contaminantspresent at the HH Burn Pit Site as well as"the source and extentsuch contaminationr

Surface..arid subsurface soil analytical results indicatedthat soil contamination is. present in on-site surface soilswithin the bermed area,"and td: a limited extent, in soils to thewest. "Subsurface soil. Contamination was found to be well-definedand confirmed the locations of the former burn pits. The.subsurface contamination is highest within these pits, but is notlimited to those areas.

»PCBs, pesticides, and a phthalate'.were detected in all soil

matrices (sediment, surface soils, and subsurface soils) atdepths up to 12 to 14 feet below ground surface ("BGS"). Aroclor1260 was the most frequently detected PCB and was found furthestfrom the Site along tne: intermittent stream (a distance ofapproximately 2,500 ft,).

Subsurface soils were also, analyzed .for inorganiccontaminants. -Since many inorganic elements occur naturally, thelevels found were;" notT considered a concern'unless they exceededthe upper limit-of the 9~0th percentile of the common ranges foundin the eastern United States. The most prevalent metals foundexceeding these levels were .copper, lead, and zinc. The highestconcentrations were generally found a"t depths of less than twofeet and occasionally to the depth of_ four feet. Beryllium,selenium, chromium, nickel, and aritimony were detected atelevated levels at random depths and lateral distribution.

Surface water samples contained Aroclor 1260 in samplescollected as far as. 400.: feet downstre~am of the Site. Since PCBsreadily adsdrb to soil or sediments,"the presence of Aroclor 1260in the unfiltered surface water samples is most likely due toPCB-contaminated particles suspended in the water. Severalsurface water samples contained cadmium, copper, iron, lead, andzinc and can be attributed to the Site, although lead and zincwere detected at low levels In background samples. This suggeststhat the presence,of lead and zinc may be a natural occurrence insurface water in the .area.

Twelve residential: wells surrounding the Site were sampledduring the RI. One" residential we 11^ "sample revealed beryllium ata low concentration slightly above the MCL (MCLs are federalstandards that were established under the Safe Drinking WaterAct). Another residential well sample detected a traceconcentration of heptachlor epoxide slightly above the Virginia

3R3U2257

Groundwater Protection Level, but below the MCL. Thisresidential well is upgradient from the Site. Sample resultsfrom a residential well located over a mile south-southwest fromthe Site revealed low to trace concentrations oftetrachloroethene (below the MCL).

Several organic contaminants including benzene, toluene,vinyl chloride, and 1,2-DCA (dichloroethane) were detected aboveMCLs in on-site monitoring well samples. The presence of lead inground water samples was attributed to Site contamination.

Aluminum, beryllium, iron, manganese, and zinc were detectedin monitoring wells both within and downgradient of the bermeddisposal area as well, but these metals were also found in atleast one upgradient monitoring well at comparable-.concentrations. The aluminum and beryllium may be at levelsnaturally occurring near the Site.

Summary of Site Kisfc?

As part of the RI/FS, EPA conducted an analysis to identifyhuman health and environmental problems that could result ifcontamination at the Site is not remediated. The analysis forhuman health problems is referred to as a Baseline" RiskAssessment ("BRA"). EPA prepared the BRA for this Site usinginformation generated during the RI/FS.

In conducting the BRA, EPA determined that human exposure tocontaminants under conditions existing at the Site could occurthrough direct contact with contaminated surface soils, surfacewater, and stream sediments, and by inhalation of airborne vaporsfrom contaminated site soils. Human health risks are estimatedby taking into account various conservative assumptions about thelikelihood of a person (located either onsite or offsite) beingexposed to contaminated media and the toxicity of the .contaminants at the Site. The exposures and risks to potentialreceptors are quantitatively evaluated in the BRA,

At present, visitors to the property and trespassers are themost likely potential receptors. If the Site were converted toresidential use, residents could be exposed to Site contaminantsthrough surface soils, surface water, and stream sediments.Further, groundwater could conceivably be used as _a domesticwater supply and contaminated subsurface soils might becomeexposed surface soils as a result of excavation and gradingactivities during development.

For the purpose of the risk assessment, contaminants wereclassified into "potential carcinogens" and "noncarcinogens."The risks posed by these two types of compounds are assesseddifferently because noncarcinogens generally exhibit a threshold

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dose below which no adverse effects occur, while, no suchthreshold can be proven to .exist"for carcinogens.

As used here, the term: "carcinogen11 means any chemical forwhich there is sufficient evidence that'exposure may result incontinuing uncontrolled cell division (cancer) in humans and/oranimals. Conversely, the terra "noncarcinogen" means any chemicalfor which the carcinogenic evidence "is negative or insufficient.

The generally acceptable excess cancer risk range, asdescribed in section 300.430(e)(2)(i)(A)Y2) of the National Oiland Hazardous Substances-Pollution Contingency Plan ("NCP"), isbetween 1.0 x 10~4. to 1/0'x'lCT6.

To determine the"systemic health threats from contaminantswhich do not .cause cancer, EPA uses the Hazard Index ("HI")- Anymedia with a cumulative HI greater :than l._p has the potential toadversely af fect=~~health. .

According to "EPA guidance, risk management decisions shouldbe based on risk"estimates for the reasonable maximum exposure("RME") case in order to ensure that the decisions are adequatelyprotective of public health.

The analysis at the HH Burn Pit Site focused on 44contaminants of concern. Of these contaminants, the majority ofthe carcinogenic risk is due to the presence of vinyl chloride,PCBs, and beryllium found in ground water at levels as high as32.2 ug/L, 1.9 ug/L, arid 19 ug/L, respectively. The MCLs forthese compounds are 1 ug/L, 0.5 ug/L and 1 ug/L, respectively.

Total estimated cancer risks for future Site residents, bothadults'and children, exceeded 10~3 (2.0"x 10~3 and 1.2 x 10~3,respectively) under the RME. "Exposures to vinyl chloride, bis(2-chloroethyl)ether, PCBs, and beryllium in ground water andexposures to PCBs in Site soils .are responsible for the majorityof the estimated- cancer risk to hypothetical future residents.Vinyl chloride is classified as.a Group A human carcinogen.PCBs, bis(2-chloroethyi)ether, and beryllium are Group B2probable human carcinogens. Vinyl chloride is associated withliver and lung cancer. \ -There is also evid.ence that berylliumexposure is associated with lung cancer. PCBs and bis(2-chloroethyl) ether, are both associated, with liver cancer in rodentstudies. :_..".....—-—-—... ". --- - -----._:-. -. -- - - -

The baseline risk assessment estimates the hazard index fornoncarcinogenic effects for future Site residents under the RMEto be 8.4 for adults and 19 for children under six years old.These risks exceed 1.0, which is the acceptable hazard indexlevel. under.average "exposure conditions, future Site residentswould experience a hazard index for noncarcinogenic effects of2.4 for adults and 7.9 for children under six years old.

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Although ingestion of manganese in ground water.is.responsible for most of the estimated ..noncarcinogenic risk,"manganese is not considered a hazardous substance under 40 C.F.R.§ 302.4, and therefore has not been used as a. basis for .requiringaction at this site.

Environmental Risk Assessment _

EPA evaluated environmental problems associated withcontamination at the Site in an Environmental Risk Assessment("ERA"). The ERA focused on surface water, sediment, and surfacesoil.

Three metals (lead, copper, and zinc) and two organics (PCSand bis(2-ethylhexl phthalate)) were identified as thecontaminants of ecological concern. Three contaminant migrationmechanisms—storm water runoff, wind, and ground water—wereidentified as agents capable of dispersing these contaminantsoff-site and into the surrounding natural environment. Bothorganic and inorganic contaminants of ecological concern are moreprone to migration via runoff and wind as opposed to dissolutionand migration in ground water. This fact is supported by theabsence or low levels of these contaminants in the ground watersampled collected from beneath the Site and from nearby parcels.

The HH Burn Pit Site is a source of environmentalcontamination in soil, sediment, and surface water on and nearthe Site. This contamination may present the potential foradverse toxicological effects to various plant and animal speciesat and near the Site. The bermed disposal area at the Site isdevegetated and supports little life, and the stream sediment hasthe potential for toxic effects as "demonstrated by toxicitytesting. The predictive risk calculations support theseobservations. The area surrounding the Site does not show anysigns of increased toxicity due to contamination present on Site.Predators at the top of the food chain and wildlife with largehome ranges would not likely be adversely impacted due to thecomparatively limited extent of the contamination. On the otherhand, localized terrestrial and riparian impacts could be seriousand aquatic impacts could extend well downstream. The RI failedto fully determine these potentials.

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Scope of Role of Remedial Action ;

EPA anticipates that the remedial action selected followingthe comment perio'd on this Revised Proposed. Remedial Action Planwill be"the"ohTy~~remedia 1 action seJLected for the Site. Theselected remedial action will add"re~ss"" ail "media impacted by Sitecontamination. EPA" believes that separation of the Site intooperable units for ;remediation_._of individual media is notwarranted.

IV. SUMMARY OF ALTERNATIVES

In preparing"the Feasibility Study ("FS") for the Site,engineering technpip.gi§s.-,app_licable to remediating thecontaminated media were screened according to their effectivenessand implementability. /£hqse; technologies .remaining after thescreening process were ;then.developed into remedial alternatives.The medium-specific remedial alternatives were developed usinginformation and data from the RI Report "~~

Because the soil des"ign"ated for "remediation is apparentlyacting as a source, of ground water contamination, it isappropriate to combine :the soil/sediment" and ground wateralternatives into comprehensive site-^wide .alternatives. Themedium-specific alternatives presented"in the FS have beencombined into the-following site-wide alternatives; . ..

• Alternative A: No action.

• Alternative B: Capping of contaminated soils andsediments, limited institutional controls.

» Alternative El: Capping of contaminatedsoils and sediments, extraction and on-sitetreatment of contaminated ground water,limited institutional controls.

• Alternative R2^ ..-Capping of contaminated soils andsediments, in situ biological treatment of ground waterwith limited.aboveground treatment

• Alternative C: Excavation of contaminated soils andsediments, on-site thermal desorption treatment oforganics-contarainated soils and sediments, on-sitesolvent extraction treatment of metals-contaminated - 'soils and sediments, on-site disposal.

• Alternative Ci: .Excavation of contaminatedsoils and sediments,"on-site thermaldesorption treatment.of organics-contaminatedsoils and sediments," on-site solvent

13 ... - . .

AR3G2263

extraction treatment of metals-contaminatedsoils and sediments, on-site disposal.Extraction and On-Site treatment of contam-inated groundwater.

Alternative C2: Excavation of contaminated soils andsediments", on-site thermal desorption treatment oforganics-contaminated soils and sediments, on-sitesolvent extraction treatment of metals-contaminatedsoils and sediments, on-site disposal, in situbiological treatment of ground water with limitedaboveground treatment.

Alternative" D: Excavation and on-site thermaldesorption treatment of contaminated soils andsediments, off-site disposal.

Alternative Dl: Excavation and on-site thermaldesorption treatment of contaminated soils andsediments, off-site disposal, extraction and On-Sitetreatment of contaminated ground water.

Alternative D2: Excavation and on-site thermaldesorption treatment of contaminated soils andsediments, off-site disposal, in situ treatment ofcontaminated ground water.

Alternative E: Excavation and off-site treatment anddisposal of contaminated soils and sediments.

Alternative El: Excavation and off-sitetreatment and disposal of contaminated soilsand sediments, extraction and On-Sitetreatment of contaminated ground water.

Alternative E2: Excavation and off-sitetreatment and disposal of contaminated soilsand sediments, in situ biological treatmentof contaminated ground wa'ter with limitedabove ground treatment.

Alternative F: In situ treatment of contaminated -soilswith steam stripping and solidification, excavation andoff-site disposal of contaminated sediments.

Alternative Fl: In situ treatment of contaminatedsoils with steam stripping and solidification,excavation and off-site disposal of contaminatedsediments, extraction and On-Site treatment ofcontaminated ground water.

14

flR3u2.26l*

. • Alternative F2-: . In situ tr eatme~=ht_ of contaminatedsoils .with steam stripping and solidification,excavation and off-site disposal of contaminatedsediments, in Situ biological "treatment of ground water.with limited :aboveground treatment.

All of "t~he-Alternatives will include monitoring ground waterquality .in...the._siaproiite and Petersburg aquifer using monitoringand residential" wells'..::"This activity will-include installationof additional- monitoring wells in both the saprolite and bedrockaquifers, ,-The__monitoring program will be outlined in theRemedial Design. In addition'7 "the Remedial Design will includean assessment of the impacts of the remedy to wetlands.

The costs presented in this document are estimates to beused solely'for the purpose"b'f 'comparative analysis...

Alternative A: NO ACTION

Capital Cost: $ o .Total O&M Cost: "-" "'"'-i -i'•:'$• 1,049,000~Total Present Worth: $ 1,049,000 ' :Implementation 'Time: " 30 years

Section 300.43"0 (e)"("67 of the NCP requires that a "No Action"alternative be evaluated at every NPL site in order to establisha baseline for.comparison. Under this alternative, EPA wouldtake no further-remedial action at the Site to prevent exposureto the contaminated media .or to reduce risks at the Site. Groundwater and surface-water;" wduTd" Toe" monitored under thisalternative. .. ,.,.-•.:.... .. ._._ -•. _.;.. ":.:"-.. . . ....

Alternative B: CAPPING OF CONTAMINATED SOILS AND SEDIMENTS,LIMITED INSTITUTIONAL CONTROLS

Capital-Cost.- _ V...$' 290,000Total O&M Cost: :: •$ 1,255,000Total Present Worth: $ 1,545.,.O.OQImplementation Time: ''" 30 years : ." '. -""" :.

Alternative B would eliminate direct contact with thecontaminated soils and sediments through the installation of aRCRA Subtitle c multilayer cap. The cap would also reducesurface water infiltration through the contaminated soil andreduce the continued migration of contaminants to the groundwater. The capped area: would be fenced to restrict access. Boththe cap and the fence would be maintained to ensure long-termprotectiveness. \~-:- -- :•?.-

Prior to capping, this alternative would include theexcavation of. contaminated, stream sediments and surface soilsbeyond .the bermed disposal area. Additional sampling would be

15

R302265

performed during the Remedial Design to determine the exactlimits of excavation. The excavated materials would be placedwithin the bermed area within the area to be capped.

Deed restrictions would be placed on the contaminated .. .. .property to prohibit future use of"the contaminated ground waterand to protect the 'Integrity of the cap. Ground water monitoringwould be continued to detect any impact to local residents .fromthe migration of ground water contamination.

A periodic review pursuant to CERCLA §121(0), 42 U.S.C.§9621(c), would be required under this alternative.

Alternative Bl: CAPPING OP CONTAMINATED SOILS AND SEDIMENTS,EXTRACTION AND ON-SITE TREATMENT OPCONTAMINATED GROUND WATER, LIMITEDINSTITUTIONAL CONTROLS

Capital Cost: $ 967,000Total O&M Cost: $ 3,736,000Total Present Ftorth; $ 4,703,000Implementation Time: 30 years • .

All of the actions described under Alternative B would beimplemented. In addition, contaminated ground water would beextracted and treated on-site to achieve the cleanup levels inTable 2. Additional field investigations would be performedduring the Remedial Design to determine the appropriateconfiguration for the extraction well network. This alternativewould include the following elements in addition to thosedescribed for Alternative B:

• Ground water extraction using pumping wells;

• Metals removal via precipitation and sedimentation;

• Organics destruction via UV oxidation;

• Carbon polishing; and

• Surface discharge of treated ground water to theintermittent stream.

A monitoring program would be implemented to measure theeffectiveness of the ground water treatment system, to evaluatepotential impacts of the system on ecological receptors, and toensure local residents are not impacted by cleanup activities.

16

3 f-, /-, ' •'! ' i t~ f~A R 0 U L L D 0

Alternative B2: CAPPING OF CONTAMINATED SOILS AND SEDIMENTS,IN SITU TREATMENT OF CONTAMINATED GROUNDWATER WITH LIMITED ABOVE-GROUND TREATMENT,LIMITED INSTITUTIONAL CONTROLS

Capital Cost: ' - $ l.,549,00_0 "..";"_."Total O&M Cost: - r - --- $ 4,239,00-0.Total Pr'Bs.ent Worth: $ 5-, 788, 000 ~Implementation Time: ' .L - .15 years '.. . '-"

All of "the"actions described under Alternative B would beimplemented. in addition,""ground"water treatment"would beimplemented primarily, by in_situ, biological treatment of phenols,ketones, and aromatic hydrocarbons (and possibly some chlorinatedhydrocarbons), and aboveground treatment of metals, pesticides,PCBs, and other non-biodegradable compounds. The treatmentsystem would extract ground water from'the center of the plume ofcontamination, treat it aboveground to remove non-biodegradablecompounds, add nutriervt£f~and oxygen needed to promote growth ofaerobic microorganisms;^ and_ reinject the water at the peripheryof the plume. This treatment system would be designed to destroythe highest concentration contaminants in situ to reduce the timerequired to r"e;ac7P~th~e ~cle~anup levels identified in Table 2.

A monitoring program would be implemented to measure theeffectiveness of the ground water treatment system, to evaluatepotential impacts of the system on ecological receptors, and toensure local resicle'nts" are."not impacted by cleanup activities.

ALTERNATIVE C: EXCAVATXON OF CONTAMINATED SOILS AND SEDIMENTS,ON-SITE THERMAL DESORPTION TREATMENT OF ORGANICS-CONTAMINATED SOILS AND SEDIMENTS, ON-SITE SOLVENTEXTRACTION TREATMENT OF METALS-CONTAMINATED SOILSAND SEDIMENTS, ON-SITE DISPOSAL

Capital Cost; ; .$ 4,992,000Total O&M Cost: ~ $ 1,0-49,000Total Present Worth: $ 6,041,000Implementation Time_:.. ._;.__!., year___ ____________^_ __

Alternative__C-provides for the. excavation of contaminatedsoils and stream :sedJ.mehts followed by on-site treatment andbackfilling at the Site;. The:organics would be treated bythermal desorption, and the metals by solvent extraction. Thetotal estimated volume of contaminated soil to be treated is5,269yd3 based on concentrations exceeding the soil cleanuplevels to a depth of six feet. " Additional sampling would beperformed durlng"~the Remedial Design to determine the exactextent of sediment excavation.

17

T7

Excavated soils and sediments would be treated by thermaldesorption to remove organic contaminants above the cleanuplevels described in Table 2. The thermal desorption processconsists of heating solids containing organic contaminants,thereby driving off the water and organic contaminants andproducing a dry solid containing trace amounts of the organicresidue. The treated soils and sediments would be backfilled on-site.

Solvent extraction would then be utilized to- remove metals.above the cleanup levels described in Table 2. Solventextraction uses a treatment tank in which soil is homogeneouslymixed, flooded with a solvent, and again mixed thoroughly toallow the waste to come in contact with the solution. Oncemixing is complete, the solvent is drawn off by gravity, vacuumfiltration, or some other conventional dewatering process. Thesolids are then rinsed with a neutralizing agent (if needed), anddried. . ... ._.. . ..__._.. . - . -

Treatability studies would be required to determine thesolvent with the best chemical characteristics needed toadequately address the conditions at the site. The solvent wouldfoe treated for reuse on-site through neutralization. Theregeneration process would generate a metals sludge which wouldbe disposed of off-site. It is expected that the sludge would behandled as a hazardous waste requiring treatment at a RCRA-permitted facility prior to disposal.

Deed restrictions would be placed on the contaminatedproperty to prohibit use of the contaminated, .ground water. ;.Ground water monitoring would be continued to detect any impactto local residents from the migration of ground watercontamination.

A periodic review pursuant to CERCLA §121(c), 42 U.S.C.§9621(c), would be required under this alternative.

ALTERNATIVE Cl: EXCAVATION OF CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE THERMAL DESORPTIONTREATMENT OF ORGANICS-CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE SOLVENT EXTRACTIONTREATMENT OF METALS-CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE DISPOSAL, EXTRACTION ANDON-SITE TREATMENT OF CONTAMINATED GROUNDWATER

Capital Cost: $ 5,646,000Total O&M Cost; $ 3,530,000.rotal Present Worth: $ 9,176,000Implementation Time: 30 years ._ .. . ..

18

AR3G2268

All of the actions described under Alternative C would beimplemented. in ""addition, ground w.ater would be treated asdescribed in Alternative: Bl. Deed^rtstrlctions would be requireduntil the cleanup standards"have been achieved.

Alternative C2: EXCAVATION OF CONTAMINATED SOILS AND- SEDIMENTS, ON-SITE THERMAL DESORPTIONTREATMENT OF ORGANICS-CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE SOLVENT EXTRACTIONTREATMENT OF METALS-CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE DISPOSAL, IN SITUTREATMENT OF GROUND WATER

Capital Cost: '" . $ ''6.~~229', 000"'"""'"'Total O&M Cost: - ~ $' -"4,033,000 '. - -Total Present Worth: $ 10-,262, 000Implementation Time: ~..; 15 .years . , ;. "

'All of""the actions described under Alternative C would beimplemented. In addition, ground water would be treated asdescribed in Alternative B2. Deed restrictions would be requireduntil the cleanup standards have been achieved.

Alternative D: EXCAVATION OF CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE THERMAL DESORPTIONTREATMENT OF CONTAMINATED SOILS ANDSEDIMENTS, OFF-SITE DISPOSAL

Capital Cost; ::; : $ 7,639,000Total O&M Cost: $ 1,049,000Total Present Worth: -$ 8,688,000Implementation Time: ,; 1 year . . . . .

Alternative D is similar to Alternative G except that nometals treatment would be provided on-site, and the excavated andtreated soils" and sediments would be disposed of off-site. Dueto the presence of regulated F001-5 RCRA-listed wastes", all . -contaminated soils .and sediments would be handled as hazardouswastes. As such, the wastes.would be treated to the extent suchwastes contained contaminants exceeding acceptable levelsestablished-in the_RCRA'Land Disposal Restrictions, and disposedof. in a RCRA Subtitle C-permitted hazardous waste landfill.

Deed restrictions would be placed on the contaminatedproperty to ..prohibit future use of the contaminated ground water.Ground water monitoring would be continued to detect any impactto local resaden~ts~~from: the migration of ground watercontamination.

A periodic review pursuant to CERCLA § 121(c), 42 U.S.C. §9621(c), would be required under this alternative.

19 ......... , _ . . . . .

SR3u2269

Alternative Dl: EXCAVATION OF CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE THERMAL DESORPTIONTREATMENT OF CONTAMINATED SOILS ANDSEDIMENTS, OFF-SITE DISPOSAL, EXTRACTION ANDON-SITE TREATMENT OF CONTAMINATED GROUNDWATER

Capital Cost: $ 8,315,000Total O&M Cost: $ 3,530,000Total Present Worth: $ 11,845,000Implementation Time: 30 years .. .

All of the actions described under Alternative D would beimplemented. In addition, ground water would be treated asdescribed in Alternative Bl. Deed restrictions would be requireduntil the cleanup standards have been achieved..

Alternative D2: EXCAVATION OF CONTAMINATED SOILS ANDSEDIMENTS, ON-SITE THERMAL DESORPTIONTREATMENT OF CONTAMINATED SOILS ANDSEDIMENTS, OFF-SITE DISPOSAL, IN SITUTREATMENT OF CONTAMINATED GROUND WATER

Capital Cost: $ 8,897,000Total O&M Cost: $ 4,033,000Total Present Worth: $ 12,930,000Implementation Time: 15 years . .. . —_— .._. ... _. .

All of the actions described under Alternative D would beimplemented. In addition, ground water would be treated asdescribed in Alternative B2. Deed restrictions would be requireduntil the cleanup standards have been achieved. . :.. .

Alternative E: EXCAVATION AND OFF-SITE TREATMENT ANDDISPOSAL OF CONTAMINATED SOILS AND SEDIMENTS

Capital Cost; $ 7,690,000Total O&M Cost: $ 1,049,00-0- ... -.Total Present Worth: $ 8,739,000Implementation Time: l year . . . .

Under Alternative E, all contaminated soils and sedimentsabove cleanup levels described in Table 2 would be excavated,treated if necessary, and disposed at an off-site landfill,.Additional sampling would be performed during the Remedial Designto determine the exact extent of sediment excavation. Due to thepresence of regulated F001-5 RCRA-listed wastes, all contaminatedsoils and sediments would be handled as hazardous wastes. -Assuch, the wastes would be .treated to the extent such wastescontained contaminants exceeding acceptable levels established inthe RCRA Land Disposal Restrictions, and disposed of in a RCRA

20

flR3Q2270

Subtitle . Cr-p.ermit.t-ed hazardous waste-landfill. For costestimation purposes, it is^ssumed^th^t soils exceedingacceptable levels wiil^be incinerated*. _____

Deed restrictions iwould be placed "on the contaminatedproperty to prohibit future use.of :the 'contaminated ground water,Ground water monitoring would:be continued to detect any impactto local" residents from the migration of'ground watercontamination.

A periodic review pursuant to CERCLA § 121(c), 42 U.S.C. § '9621(c)V" ould be required..under' this alternative.

Alternative El: EXCAVATION AND OFF-SITE DISPOSAL OFCONTAMINATED SOILS AND SEDIMENTS, EXTRACTIONAND ON-SITE TREATMENT OF CONTAMINATED GROUNDWATER

Capital Cost: ': ' $ 8,366,0~OVTotal O&M Cost: " " $" 3,530,000 :": "Total Present'Worth: $ 11,896,000 " " ." " 'Implementation Time: ".;.:. 30 years . . . . . . :

All' of "the .actions described under Alternative E would beimplemented. In addition, gro'und"water would be treated andmonitored as-described in Alternative Bl. Deed restrictionswould be required until the cleanup standards have been achieved.

Alternative E2: EXCAVATION AND OFF-SITE DISPOSAL OFCONTAMINATED SOILS AND SEDIMENTS, IN SITUTREATMENT OF CONTAMINATED GROUND WATER

Capital Cost: .:_...$__ £,948,000 _ _ ' . " : "..Total O~&M Cost: " "::- ~$ ~4,033,000Total Present Worth: $ 12,981,300 ..Implementation Time: 1 5 , years " . . . " -

All of the "actions described under Alternative E would beimplemented. In addition, ground water would be treated asdescribed in Alternative B2. Deed restrictions would be requireduntil the cleanup standards have been achieved.

21

Alternative F: IN SITU TREATMENT OF CONTAMINATED SOILS WITHSTEAM STRIPPING AND SOLIDIFICATION,EXCAVATION AND OFF-SITE DISPOSAL OFCONTAMINATED SEDIMENTS

Capital Cost: $ 4,682,000Total O&H Cost: - $ 1,049,000Total Present Worth: $ 5,731,000Implementation Time: 1 year " "" :~r i

This alternative treats soils" via in situ techniques. Insitu steam stripping would force stream into "areas'of organiccontamination to volatilize the contaminants. The area beingtreated would be enclosed to capture the volatilizedcontaminants. In situ solidification would be used to immobilizemetals found in contaminated soil. Large bore augers are used topenetrate and mix the soil. Solidification agents such as ...Portland cement, silicates, or other proprietary additives areintroduced through the auger to the soil.

Sediments, because they are located near the surface, arenot good candidates for the in situ technologies identified forthis Site's contaminants. Therefore, contaminated sedimentswould be excavated and disposed of off-site. Additional samplingwould be performed" during the Remedial Design to determine theexact extent of sediment excavation. For costing purposes, it isassumed that the contaminant levels-"in the excavated sedimentsare below the RCRA Land Disposal Restriction treatment standards.Under thess circumstances, treatment would not be required andthe excavated sediments wojald be disposed of off-site in a -RCRASubtitle C-permitted hazardous waste landfill. Additional.sampling of the sediments would be performed during the remedialdesign to determine the need for treatment.

Deed restrictions would.-be placed on the contaminatedproperty to prohibit future use of«the contaminated ground waterand to ensure that solidified contaminants are not disturbed.Ground water monitoring would be continued to detect any impactto local residents from the migration of ground watercontamination.

A periodic review pursuant to CERCLA § 121(c), 42 U.S.C. §9621(c), would be required under this alternative.

22

SR3G2272

Alternative Fl: IN SITU TREATMENT OF CONTAMINATED SOILS WITHSTEAM STRIPPING AND SOLIDIFICATION,EXCAVATION AND OFF-SITE DISPOSAL OFCONTAMINATED SEDIMENTS, EXTRACTION AND ON-SITE TREATMENT OF CONTAMINATED GROUNDWATER

Capital Cost: - _ $ 5,358,.OaD- ' ::.:''.:'Total O&M Cost: ". --'-].—$ 3/530. 000"'" " " .Total Present Worth: - $8,888,000 " .

Time: .30. years. . .. ..

Al-1 of the actions described-under Alternative F would beimplemented. Tn addition, ground'water' would be treated asdescribed -in Alternative Bl".~ " Deed 'restrictions would be requireduntil the cleanup standards have been achieved.

Alternative F2: IN SITU TREATMENT OF CONTAMINATED SOILS WITHSTEAM STRIPPING AND SOLIDIFICATION,EXCAVATION AND OFF-SITE DISPOSAL OFCONTAMINATED SEDIMENTS, IN SITU BIOLOGICALTREATMENT OF GROUNDWATER WITH LIMITED ABOVE-GROUND TREATMENT

Capital Cost: - .-... .. .; '$-5.,..9.40,00-0".Total O&M Cost: : $ 4,033,000Total Present Worth:.-. $ 9,973,000Implementation Time: ~"; ~"~ 15 years ... "...

All of "the actions described -under Alternative E would beimplemented. . Irf addition, "ground 'water would be treated asdescribed in Alternative B2. ..Deed restrictions would be requireduntil the cleanup standards have been achieved.

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VI. SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

This section provides a description of the nine criteria EPAis required to consider;.under .CERCLA . and__Section300.43aC^T"(Vn"ii^) of the NCP, 40 C.T.R. § 300.430(e) (9) (iii) , inevaluating remedial alternatives "and 7an Analysis of .thealternatives "-considered'by EPA for implementation at theproperties .covered by this Proposed:Remedial Action Plan. Thenine criteria., are:..-.. . __j:--. , ...-:._:-..-.„.„.._.. .- .....^--; ..---L__ ...... _

A. Threshold Criteria:''Statutory requirements that eachalternative must satisfy 'in order'to be eligible forselection."" " ""

1) Overall P.r-0_tectio.n_or£_Huma.n Health and the Environment

Evaluation of.the ability of"each alternative to.provide adequate protection of human health and theenvironment in the long and short-term; description ofhow risks posed through each exposure pathway areeliminated, reduced," or controlled through treatment,engineering controls, or institutional controls.

2) Compliance with Applicable or Relevant and AppropriateRequirements (ARARs i

Evaluation'o'lT'the ability of each alternative to attainapplicable or-; relevant and appropriate requirements

1 under.,.federal" environmental'1 laws' and stateenvironmental or facility siting laws or providegrounds for .invoking a .waiver ..established under CERCLA.

B. Primary Balancing Criteria: -Technical criteria uponwhich the detailed: analysis".is primarily" based.

3) Long-Term Effectiveness and Permanence

Evaluation of'expected residual risk and the ability ofeach alternative to maintain reliable protection ofhuman health and the environment-over time aftercleanup requirements have been met.

4) Reduction of Toxicitv, Mobility, or Volume throughTreatment

Evaluation of'the degree to which an alternative .employs treatment methods to reduce the toxicity,mobility, or volume of hazardous substances at thesite.. .. - . ..." .... . . . " ^

25

flR3u2275

5) Short-Term Effectiveness _._..... _.__

Evaluation of the period of time needed to achieveprotection and any adverse impacts on human health andthe environment that may be posed during'theconstruction and implementation period. • ..

6) Xmplementabilitv

Evaluation of the technical .and administrativefeasibility of each alternative, including theavailability of materials and services.

7} Cost

Section 121 of CERCLA, 42 U.S.C. § "9621",~r"5qUire"3"selection of a cost-effective remedy that protectshuman health and the environment and meets the otherrequirements of the statute. "Alternatives are comparedwith respect to present worth cost, which includes allcapital costs and the operation and maintenance costincurred over the life of the project. Capital costsinclude expenditures, such as construction costsfnecessary to implement a remedial action. All costspresented are estimates computed for comparisonpurposes only.

C. Modifying Criteria: Criteria considered throughout thedevelopment of the preferred remedial alternative andformally assessed after the public comment period.

8) state Acceptance

Assessment of the State's position and key concernsrelating to EPA's preferred remedial alternative andother alternatives and the State's comments on ARARs orthe proposed use of waivers.

9) Community Acceptance ^ . . _ . . . . . .____. ___ .__ _. __ r

Consideration of the community's concerns on theproposed remedial action plan articulated during thecomment period. —--

1. Overall Protection of Human Health and the Environment

Alternatives that do not include remediation of the groundwater contamination at the Site do not address potential humanhealth risks posed by use of ground water. Alternatives A, B, C7D, E, and F, therefore, do not meet this threshold criteria for

26

AR302276

overall p'rotec.tioh of" human health* a3d the environment and willnot be considered further in this analysis.

Alternatives Bl and B2 reduce .risks posed via Site soils,sediments, surface water, and ground water by capping thecontaminated soils and sediments in" the disposal area(contaminated sediments "willVbe removed and consolidated into thedisposal area "pr~ior "to": capping) and extracting and treating theground water-.. Re"duced;"rlsk ._w_ilL_o_rily be achieved if the cap isproperly maintained and the extraction system continues tooperate..... ...... . __.=~,!_~ __— —— ..-•- ... . . . . . ........

Alternatives Cl, C2, Dl, D2, El, E2, Fl, and F2 alleffectively reduce risks posed by the Site through treatmentand/or disposal of soils and sediments and. treatment of.contaminated ground water. -Alternatives Cl and C2 treat thesoils and sediments to" health-based cleanup levels. AlternativesDl and D2 treat organic contaminants on-site, then dispose, of thetreated soils and sediments in an off-site landfill.Alternatives "Fl.._and F2:treat_soils on-site to health-basedcleanup levels aWdisjpbse of sediments in an off-site landfill.Alternatives El and E2 dispose"of.soils and sediments in an off-site landfill. " " "" " "' • —•••——- — -•- ——

2. Compliance with Applicable or Relevant and AppropriateRequirements (ARARs)

Under Section 121(d) of CERCLA, 42 U.S.C. § 9621(d), and EPAguidance, remedial actions at Superfund" sites must attain legallyapplicable or relevant and appropriate Federal and stateenvironmental standards, requirements, criteria, and limitations(collectively referred;to7as -ARARs). Applicable requirements arethose substantive environmental protection requirements,criteria, or-limitations promulgated under Federal or state lawthat specifically address hazardous substances found at the Site,the remedial action to:be implemented at the Site, the locationof the Site, or other circumstances at the Site. Relevant andappropriate requirements are -tho.se. which, while not applicable tothe Site, nevertheless address problems or situationssufficiently similar to" those encountered at the. Site that theiruse is-well suited to that Site. ARARs can be "chemical"specific, "action" specific, or "location" specific.

a- Chemical-Specific ARARs_ .r -.

Chemical-specific'soil .ARARs exist only for PCBcontamination. The PCB ARAR would not be met with AlternativesBl or B2. Alternatives Cl, C2, Dl, D2, El, and E2 will meet thesoil ARARs through soil" excavation arid/or "treatment. Dependingon the performance of in situ, steam" stripping, Alternatives Fland F2 may or may not"attain the ARAR.

27

a**» f' "* j*>. Vi •*] - -v

HOU 2 Li 1

Chemical-specific ARARs for ground water exist, as federal.drinking water standards and state .ground water qualitystandards. Alternatives Bl, B2, Ci, C2, Dl, D2, El, E2, Fl~, andF2 would meet the ground water ARARs through extraction andtreatment or in situ treatment throughout the saprolite aquifer.Long extraction and treatment durations may be required beforeARARs are achievedr :: •

b. Action-Specific ARARs ... _- -

All alternatives discharging treated ground water(Alternatives Bl, ci, Dl, El, and Fl) would meet the substantivestate and federal discharge requirements. Alternativesreinjecting ground water as part of an in situ treatment program(Alternatives B2, C2, D2, E2, and F2) would meet the requirementsof the VDEQ for ground water injection.

Alternatives Bl and B2 would meet action-specific ARARs forcap construction. Soils treated by thermal desorption underAlternatives Cl, C2, Dl, and D2 or by in situ steam strippingunder Alternatives Fl, and F2 would meet air emission criteria.If total PCB concentrations greater than 50 mg/kg are treated bythermal desorption, the system would need to^.pravide treatmentequivalent to that required by a TSCA-permitted incinerator.

Alternatives Dl, D2, El, E2, Fl, and F2 would meet action-specific ARARs for excavation, staging, transportation, and off-site disposal at a RCRA-permitted landfill.

c- Location-Specific ARARs

Location-specific ARARs for the Site are limited torequirements to maintain the integrity of the wetlandssurrounding the Site during remediation.

Alternatives Bl, B2, Cl, C2, Dl, D2, El, E2, Fl, and F2would impact wetlands to a similar degree, principally throughexcavation of contaminated sediments. Alternatives involvingextraction, treatment, and discharge of ground water(Alternatives Bl, Cl, Dl, El, and Fl) could potentially lower thewater table beneath the wetlands and partially dehydrate them.This impact could potentially be minimized by discharging thetreated ground water directly to the wetlands.

3. Long-Term Effectiveness and Permanence

Alternatives Bl and B2 rely on continued maintenance of thecap and the continued implementation of ground water .treatment toprovide long-term, effectiveness. These alternatives areconsidered less effective over the long term than alternativesthat remove contaminants from the Site through treatment or off-site disposal. .- ... . . ——.

28 .:

4R3G2278

Alternatives Cl, C2, JDI, D2," El_, and E2 provide asignificant level of lorig'-term "effectiveness through treatment ofcontaminated soils, sediments,- and ground water. Alternatives Fland F2 provide: "a" similar level of IbhgT-'term"5 effectiveness throughtreatment of contaminated, soils and ground water. UnderAlternatives Fl and F2, sediments::"are also removed from the Siteand disposed "in an "off-site .landfill. - . .

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

Alternatives Cl and C2 provide the highest reduction oftoxicity, mobility and volume through treatment. All media wouldbe treated on-site to remove Site, contaminants. Concentratedwaste generated by the on-site-. treatment processes would then betaken off-site, .for ..further treatment and/or disposal.

Alternatives Dl, D2, El, E2, Fl, and F2 also achievesignificant reductions ;of toxlcity, mobility, or volume throughtreatment. Under .Alternatives Dl and ~D2, Site contaminants areremoved frotiflall media^through treatment with the exception ofmetals in soil. Soils with metals -contamination are disposedoff-site. Under Alternatives El and E2, soils and sedimentscontaminated at levels :exceecling the RCRA Land Disposal.Restriction treatment standards would be treated off-site priorto disposal. Site contaminants are,also removed from groundwater through treatment under .Alternatives El and E2. UnderAlternatives Fl and F2, Site contaminants" are removed from soilsand ground water. Sediments are disposed off-site. As withAlternatives Cl and C2, concentra/ted wastes generated by removingSite-contaminants through on-site treatment processes wouldrequire further treatment and/or disposal off-site.

Alternatives Bl arid B2 reduce the toxicity, mobility, andvolume of Site contaminants in ground water through treatment.These alternatives do not treat Site contaminants in the soilsand sediments. ~ _ - : : .

5. Short Term Effectiveness

Alternatives~,Bl, B2, Cl,r~C2, Dl, D2, El, E2, Fl and F2 wouldcause a temporary increase in the amount _of dust produced, noisedisturbance, and truck traffic. Alternatives Dl, D2, El, E2, Fland F2 would produce "greater amounts of truck traffic due to theincreased use of off-site disposal. Alternatives Cl, C2, Dl, andD2 utilize on-site thermal desorption. Although this processproduces an offgas, pollution control equipment would eliminatepotential threats to nearby residents during .operation. In situsteam stripping (Alternatives Fl and F2) also generates an offgasthat would re'qulre "treatment.

Alternatives Bl and B2 would require the least amount oftime to implement. Alternatives El and E2 could be implemented

29

AR3G2279

faster than Alternatives Cl, C2, Dl, D2, Fl and F2,~ as no thermaldesorption or in situ treatment would be carried out on-site.Groundwater treatment for Alternatives Bl, B21_ Cl, C2, Dl, D2,El, E2, Fl, and F2 would continue for many years, although thetreatment duration for Alternatives Bl and B2 will likely belonger since the source of contamination will not be removed. ._

6, Implementability

The cap required in Alternatives Bl and B2 can be readilyimplemented. Most soil and groundwater treatment, processes forAlternatives Bl, B2, Cl, C2, Dl, D2.., El, E2, Fl, and F2 could bereadily implemented as well. As Alternatives Fl and F2 treat thesoil in situ, it may be difficult to ensure that all contaminatedsoil is treated. The in-situ groundwater treatment component ofAlternatives B2, C2, D2, E2, and F2 may be difficult to implementif Site conditions prove unsuitable for promoting subsurfacebacterial growth, or if other problems arise, such asdifficulties in reinjecting treated water and/or,providingsufficient oxygen to the groundwater plume. Treatability studieswould be required during the remedial design to determine theimplementability of the in situ ground.water treatment component.

7. Cost Effectiveness

The alternatives presented in the FS were expanded andcosted in this Revised Proposed Remedial Action Plan to presentoptions that addressed soil and sediments alone, as well as twodifferent options that addressed contaminated ground water—together with soils (extraction and treatment and in situbioremediation of ground water). The estimated costs associatedwith each of the alternatives are presented in Table 4.

3. State Acceptance

The Commonwealth of Virginia has reviewed the RI and FSreports and will indicate its concurrence or nonconcurrence withthe selected alternative following the public comment period forthis Revised Proposed Remedial Action Plan.

9. Community Acceptance

Community acceptance of the preferred alternative and "theother alternatives will be evaluated following the public commentperiod and addressed in the Record of-Decision.

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3u228G

Table 4 - .

COST .SUMMARY OF REMEDIAL ALTERNATIVES

ALTERNATIVE

A

B

Bl .

B2 . ..__

C

Cl

C2

D

Dl

D2

E

El - .: -E2

FFl . -:;-;—

F 2 . . . . . . . . .

-CAPITAL. COST.

-0-

$ 290,000

$ 967,000

$1,549/00:0

$4,992,000

$5,646,000 '

$6,229,000"

$7,639,000

,$8,315,000

$8,897,000

$7,690, "000 .

$8,366,000 -.-:.

$8,948,000

$4, 682,000

$5,358,000

$5,940,000 -'

PRESENT WORTHO & M

$1,049,000

$1,255,000

$3,736,000

$4,239,000

$1,049,000

$3,530,000

$4,033,000

$1,049,000

$3,530,000

$4,033,000

$1,049,000

$3,530,000

$4,0.33,000

$1,049,000

$3,530,000

$4,033,000

TOTAL" COST

$1,049,000

$1,545,000

$4,703,000

$5,788,000

$6,041,000

$9,176,000

$10,262,000

$8,688,000

$11,845,000

$12,930,000

$8,739,000

$11,896,000

$12,981,000

$5,731,000

$8,888,000

$9,973,000

31

ftR3u228

VII. EPA'S PREFERRED REMEDIAL ALTERNATIVE

At this time, EPA prefers Alternative El to remediate-thecontamination at the site. This alternative would substantiallyreduce the risks at the Site,by removing the principal threatposed by soil and sediment contamination through excavation andtreatment of contaminated wastes, and placement of"such wastes ina permitted disposal facility. Contaminated ground water wouldbe collected by an extraction well-.system constructed in the areaof the contaminant plume. The contaminated ground water would betreated via carbon adsorption, precipitation/ and sedimentationto remove the VOC, PCB, and metals contamination. Treatmentwould reduce the levels of contaminants to those set by the VDEQWater Division prior to discharge to the- ground surface.

Based on the information available at this time, EPAbelieves the preferred alternative would be protective of humanhealth and the environment, would _comply with ARARs, would becost-effective, and would use permanent solutions and alternativetreatment technologies to the maximum extent practicable. Thisalternative makes use of existing fully permitted treatment anddisposal facilities. Extensive treatability studies that wouldbe required under Cl, C2, Dl, D2,~E2, Fl, and F2 will not benecessary prior to implementation of this remedy. The remedyalso meets the statutory preference for use of a remedy whichpermanently and significantly reduces the toxicity, mobility, orvolume of the hazardous substances, pollutants, or contaminantsas a principal element and it is within the expectations of theNCP which states that EPA will treat principal threats posed bythe contamination at the Site. Alternatives Bl and B2 do notcontain treatment components for soils and sediments.

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AR3C22ff2

GLOSSARY

Administrative _R_e_c_o_r_d - Compilation of documents, data, reports,and other information, supporting selection of a response action.The record is placed in the information repositories to allowpublic.-access.".to the .material.- .. ...._. -. - ..... ...._... -._=,... . .

Aquifer - .An__yndergrd-uhti geologic^ fprtriation, _or group offormations, "containing useable amounts of ground water" that cansupply wells and springs".' " " :"~7TT~~..,._._,...;.,.-..--,

ARARs - Applicable, Relevant ..and Appropriate Requirements:

Applicable requirements;are those cleanup standards, standards ofcontrol-, and other substantive environmental protectionrequirements, criteria, or limitations promulgated under Federalor State law that specifically address a hasardous substance,pollutant:, "contaminant, " remedial action, location, or othercircumstance at'a-CERCLA site.

Relevant and Appropriate requirements are those same standardsmentioned above that while not "applicable" at the CERCLA site,address" problems or situations, sufficiently similar to thoseencountered at the site: that their use is., well suited to theparticular site. .:• --------r—.-.- -~--~

Biological Treatment -.^Generally refers to the breakdown oforganic compounds (contaminants] by micro-organisms.

Capping - Construction of a protective cover over areascontaining wastes or contamination. Caps prevent surfaceexposure of the., contaminated soils and. sediments and reduce oreliminate infiltration of rain water or other precipitation intothe soils/sediments. This minimizes the movement of contaminantsfrom the site through ground water or surface water.

Carcinogen -,._.A. cancer-causing agent, .. _ _.__ .____

CERCLA -. see. .SUPERFUND.._:. .. .._.. ..___. .- ..__.._.-

CFR - The. Code .of .Federal Regulations. ...For example, the citation40 CFR Part 2J5JO.-means Title 40 of the Code of FederalRegulations, Part 260. "; - - ':'...:.. "-

Desorption - The_physical process of separating a volatilecompound from a liquid mixture^ into :a gas.

Ex aitu BioremedlafcijQn - Treating soils in an above-gradetreatment system using conventional soil management practices toenhance microbial degradation of contaminants.

33

n ?•»*"** -" •"• o OA R 0 U L L 8 ,1

Respons iveness Summary - A summary of .oral and/ or .written publiccomments received by EPA during a comment period on key EPA" "" " ~documents, and EPA's responses to those comments. Therespons iveness summary is a key part of the ROD, highlightingcommunity concerns for EPA decision-makers.

Risk Assessment (Rff) - The RA is an_ essential component of theRemedial Investigation ("RI") Report. This portion of the RIevaluates the carcinogenic and non-carcinogenic risks presentedby the contaminants at a site. Risk is calculated both forcurrent uses and potential future uses of the property by a^defined population, ( i.e. . on and offsite residents'," trespassers,etc.)

Saprolita - A soft, typically clay-rich material that resultsfrom in-place chemical weathering of sedimentary, igneous, ormetamorphic rock. Saprolite can be characterized by preservationof original structures associated with the unweathered rock.

Scientific Notation - In dealing with particularly large or smallnumbers, scientists and engineers have developed a "-short hand"means of expressing numerical valuers. For example, 1,00*0,000 canbe written as 1 x 106 and 1/1,000,000 can be written as 1 x 10"®.

(Comprehensive Environmental Response Compensation andLiability Act -_ _A__ federal law passed in 1980, and amended 'in1986, which enables EPA to investigate and clean up hazardouswaste sites using Federal funds and/or .to require such actions bycertain classes of persons defined "as responsible uTTder thestatute.

Volatile Organic Compounds (VOCs) -. Chemical compounds containingcarbon that readily volatilize or evaporate when exposed to theatmosphere.

34