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FILE COPYSuperfundRecord of Decision:
Superfund Records CenterSITE:BREAK:OTHER:
Western Sand & GravelSite, Rl
SDMS DocID 259691
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TECHNICAL REPORT DATA(Pleate read Jnttnicnons on the rtvtrtt be fort completing)
1. REPORT NO.
EPA/ROD/R01-84/006
2.
4. TITLE AND SUBTITLE
SUPERFUND RECORD OF DECISION:Western Sand & Gravel Site, RI
7. AUTHORtS)
•9. PERFORMING ORGANIZATION NAME AND ADDRESS
12. SPONSORING AGENCV NAME AND ADDRESS
U.S. Environmental Protection Agency401 H Street, S.W.Washington, D.C. 20460
3. RECIPIENT'S ACCESSION NO.
6. REPORT DATE
09/28/846. PERFORMING ORGANIZATION CODE
• . PERFORMING ORGANIZATION REPORT NO
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
13. TVPE OF REPORT AND PERIOD COVERED
Final ROD Report14. SPONSORING AGENCV CODE
800/00
16. SUPPLEMENTARY NOTES
16. ABSTRACT
This semi-rural site has been a sand and gravel mining operation owned byWestern Sand and Gravel/ Inc., since 1953. In 1975 approximately 12 acres of the20-acre site were used for the disposal of 480,000 gallons of liquid wastes, in-cluding chemicals and sewage waste. These wastes were dumped into unlined lagoonsand seepage pits. Ground water contamination has occurred at the site and a plumeof contamination is moving towards domestic wells adjacent to the site.
The selected cost-effective remedial alternative includes: the installationof a permanent alternate water supply to service approximately 56 parcels of land,and the installation of carbon canister filters as a temporary abatement measurefor 8 homes with contaminated wells until the permanent water supply is functional.
Key Words: Cost Factors; Fire Protections Water Supply System; AlternateConcentration Limit (ACL); Ground Water Contamination; RCRA,Enforcement; Negotiated Settlement; Ground Water.Cleanup;Ground Water Strategy
KEV WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS b . l D E N T l F I E R S / O P E N E N D E D TERMS COSATI Field/Croup
Record of DecisionWestern Sand & Gravel Site, RIContaminated media: gw, soilKey contaminants: VOCs, solvents, TCE,
acids
IB. DISTRIBUTION STATEMENT 19. S E C U R I T Y CLASS fTllli Report/
None2V I
4020 SECURITY CLASS (Thilfggtl
None"22.
EPA F»rm 2JJO-1 (•*••• 4-77) P r e v i o u s E D I T I O N n o»tou«Te
INSTRUCTIONS
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•
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14. SPONSORING AGkNCY CODEInsert appropriate code.
IB. SUPPLEMENTARY NOTESEnter information not included eliewhere but useful, such av Prepared in cooperation with. 1 r.m\Uli<>i> t»l. IVcM/iiu-d at oinu-n-mi- ol.To be published in, Supersedet, Supplemenu. etc.
16. ABSTRACTInclude a brief (200 word* or less] factual summary of the most sifmfii-iinl intornui>»o lonumol in ilu- u-|xiri. Il ilu- ir|x>n innums aUfniHcant bibliopaphy or literature survey, mention it here.
17. KEY WORDS AND DOCUMENT ANALYSIS(a) DESCRIPTORS • Stlrci from the Thcuuim of tngmccrir.» and Sui-milK Terms the proper auil»»i/cd Ii-iius Hut idennly the majorconcept of the research and are sufficiently tpecit'ic and precise to be UK-J as index enirict lor caulut:in|:.
(b) IDENTIF1CRS AND OPEN-ENDED TERMS - Use identifier! for project nanii.%. code names, ev|uipmenl dcMcnalutv. etc. t'w itpcn-ended terms written in descriptor form for those subjects for which no descriptor exists.
(c)COSATi t ll.LD GROUP - 1 ieW an d Rroup awigrimenti art lobe token from rhc IV65COSA1I Suli(t-ir ( aii-piry List. Since the ma-jority of documents are multidijciplinary in nature, the Primary I itld /Group j^nnmtnUv) will be spt'iilu Ji^iplinc.areii <>l liunun
' endeavor, or type of physical object. The application^) will be ctow-rcUicntxti with -*.-rondjry I K-ld/( .ruup 4\sipnmcnis that will loll"*the primary
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Insert the price set by the National Technical Information Service or the Government Printing Office, il known.
EPA Fwm 2220-1 (R*«. 4.77) (*•»•••••>
ROD ISSUES ABSTRACT
Western Sand and Gravel, Inc.Burrillville, Rhode Island
Region; I
AA, OSWERBriefing Date: June 25, 1984
SITE DESCRIPTION
This semi-rural site has been a sand and gravel mining operationowned by Western Sand and Gravel, Inc., since 1953. In 1975approximately 12 acres of the 20-acre site were used for the disposalof 480,000 gallons of liquid wastes, including chemicals and sewagewaste. These wastes were dumped into unlined lagoons and seepagepits. Ground water contamination has occurred at the site and a plumeof contamination is moving towards domestic wells adjacent to the site.
SELECTED ALTERNATIVE
The selected cost-effective remedial alternative includes: theinstallation of a permanent alternate water supply to serviceapproximately 56 parcels of land, and the installation of carboncanister filters as a temporary abatement measure for 8 homes withcontaminated wells until the permanent water supply is functional.
ISSUES AND RESOLUTIONS KEY WORDS
t
1. The alternate water supply system will provide . Cost Factorscapacity for fire protection, based on current . Fire Protectiondemand, because of the minimal additional cost. . Water Supply
System
2. Although the final remedial action will . Alternateprovide for source control measures, the Concentrationground water in the vicinity of the site Limit (ACL)will remain contaminated. The selected . Ground Waterremedial measure (alternate water supply) Contaminationwill abate the public health risk associated . RCRAwith the contaminated ground water and theRI/FS indicates that there will not beadverse impacts to ground water receptors.If CERCLA actions are required to be in
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Western Sand and Gravel, Inc., Rhode IslandJune 25, 1984Continued
ISSUES AND RESOLUTIONS KEY WORDS
conformance with the technical provisions ofRCRA, corrective action must be taken toaddress the remaining contaminated groundwater or an Alternate Concentration Limit(ACL) established. The Region submitted aproposal for an ACL at the site. It wasdetermined that there was insufficient datato warrant an ACL at this time.
The negotiated eighty percent settlement will . Enforcementbe rejected because additional ground water . Negotiatedinvestigation and possible future remedial Settlementactions may be required to mitigate the con-taminated ground water.
Since this ROD did not address all the ground . Ground Waterwater issues pertaining to site closure. Cleanupa future ROD will be prepared for Western . Ground WaterSand and Gravel to focus on the cost impli- Strategycations and technical considerations forcleanup of the contaminated ground water.This ROD will also incorporate the Agency'sground water strategy into the recommendedalternatives.
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RECORD OF DECISIONREMEDIAL ALTERNATIVE SELECTION
Site_:_ Western Sand and GravelBurrillville. Rhode Island
DOCUMENTS REVIEWED:
I am basing my decision primarily on the following documentsdescribing the analysis of cost-effectiveness of remedialalternatives for the Western Sand and Gravel Site:
0 Remedial Investigation/Feasibility Study for WesternSand and Gravel. Arthur D. Little, Inc., May 22, 1984.
0 Remedial Investigation/Feasibility S tudy for WesternSand and Gravel. Arthur D. Little Inc., January 31, 1984.
0 Remedial Investigation/Feasibility Study for WesternSand and Gravel, Arthur D. Little. Inc. October 5, 1983.
0 Test Pit Explorations. Goldberg-Zoino and Associates,June 1981.
0 Letter from Philip P. Virgadamo of Environmental ResourcesAssociates, Inc. to Christine J. Spadafor, EPA Region ISite Manager, April 9, 1984.
0 Staff summaries and recommendations.
0 Responsiveness summary dated June 1934.
O PTIONS :
0 Installation of water filters as an Initial RemedialMeasure to provide protection for homes with contaminantsidentified in their wells, until the permanent alternatewater supply is functional.
• Installation of a permanent alternate water 'supply toservice approximately 56 parcels of land.
DECLARATIONS :
Consistent with the Comprehensive Environmental Response.Compensation and Liability Act of 1980 (CERCLA), and theNational Contingency Plan (40 CFR Part 300), I have determinedthat the remedial action providing for a permanent water supplyat the Western Sand and Gravel site is a cost-effective remedyand provides adequate protection of public health, welfare, and
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the environment, with respect to present drinking watercontamination. I have also determined that the installationof filters on individual homes as an initial remedial measureis a cost effective remedy and provides adequate protection •of public health, welfare, and the environment. The Stateof Rhode Island has been consulted and agrees with the approvedremedy, since it is consistent with the conditions that theState believes are appropriate for this site. In addition,some actions will require future operation and maintenanceactivities to ensure the continued effectiveness of the remedy.These activities will be considered part of the approved actionand eligible for Trust Fund monies for a period not to exceedone year.
I havp also determined that the action being taken isappropriate when balanced against the availability of TrustFund monies.used at other sites. In addition, the agency willauthorize the, collection of additional contamination and groundwater data necessary to characterize the requirements of sourcecontrol and site closure.
EPA will also undertake an additional study to evaluatealternative ground water corrective actions. If additionalremedial actions are determined to be necessary, a Record ofDecision will be prepared for approval of the future remedialaction.
Rate Lee M. ThomasAssistant AdministratorOffice of Solid Waste & Emergency Response
SUMMARY OF REMEDIAL ALTERNATIVE SELECTIONWestern Sand and GravelBurrillville, Rhode Island
SITE HISTORY AND DESCRIPTION rf
The Western Sand and Gravel site is located in Burrillville,Rhode Island, adjacent to the Douglas Pike and close to the townline of North Smithfield. Historically, this semi-rural site wasa gravel mining operation owned by Western Sand and Gravel, Inc.,and operated by Mr. James Cardi since about 1953.
Beginning in about 1975, approximately 12 acres of the 20acre site were used for the disposal of liquid wastes, includingchemicals and sewage waste (see Figure 1). Wastes were dumpedinto four chemical lagoons and eight or more seepage pits. Alllagoons and pits were unlined. The waste pits and lagoons were80 to 100 feet'.long, 18 to 20 feet wide and 8 to 10 feet deep.The wastes subsequently infiltrated into the soil, percolatingthrough the highly permeable soils into the groundwater.
There are approximately 56 parcels of land within 1/2 mileof the site affected or potentially affected by the contaminantsmigrating off-site. The Remedial Investigation/Feasibility Study(RI/FS) determined that ground water has been contaminated byhazardous waste at the site and is moving in a northerly directionto domestic wells adjacent to the site. There are approximately600 persons that are served by groundwater via private drinkingwells within a one mile radius of the site. The contaminatedground water also discharges into both the Tarkiln Brook and theSlatersville Reservoir. The Reservoir is used for recreationalpurposes and is not a source of drinking water. However, thesite does overlie the Slatersville Aquifer, a major ground wateraquifer for the State of Rhode Island.
In May of 1975, the Rhode Island Department of Health approveda request by Mr. Cardi to dispose of sewage waste in two trenchesat Western Sand and Gravel. These operations continued and wereinitially monitored by the Rhode Island Division of Solid WasteManagement in March 1976. In November 1976, a chemical pit wasidentified during a site inspection by the Rhode Island Divisionof Solid Waste Management, and acid wastes were observed beingdisposed of during a subsequent site visit in January 1977. Afire occurred in one of the chemical pits in March 1977, andofficials from the Burrillville and North Smithfield Fire Depart-ments ordered Mr. Cardi to remove the chemicals from the site.Mr. Cardi responded by burying the contents of the chemicallagoon. During the period of April through August 1977, therewere a series of State court hearings held related to Mr. Cardi'sviolations of guidelines for the disposal of septic tank andcesspool wastes. Also, the State received complaints from nearbyresidents, regarding chemical odors emanating from the WesternSand and Gravel site.
FIGURE iWESTERN SAND AND GRAVEL
HYDROGEOLOGIC SETTING QSLATEKSVN.IE
AQUIFERTMAMSNNSSIvrrV
SOOOMOOFT'/DAV
APPROXIMATE / /LOCATION / /OF PLUME / /
SlATERSVNiERESERVOIR
SHE CN1AIHUOTO SNOW K1AI
ttOtNO
SUIDOE
MIXED SON. • tlUOGE
SON. ft TRACE AMOUNTS OP SUIOQE
SURFACE CONTAMINATION
A COtHAMMAttD DOMtSIIC
MOMTOMMO Wtti IOCATIONS
• SURFACE SAMPUNO UXATIONS
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The Rhode Island Department of Environmental Management (DEN)was formed in October 1977 and this agency forwarded emergencyindustrial waste regulations to Mr. Cardi in December 1977.Mr. Cardi responded to these regulations by notifying DEM in March1978 that the site was an industrial waste disposal site*. Therewas no further regulatory activity (other than inspections) duringthe remainder of 1978.
In January 1979. concern of local residents and State officialsover the site resulted in a joint meeting of the Burrillville andNorth Smithfield town councils to discuss the operations at thesite. Private domestic wells in the area of the site were sampledby the Rhode Island Department of Health for contamination and inFebruary 1979, a Notice of Violation Order was sent to Mr. Cardiby DEM. A Cease and Desist Order was issued by DEM on April 24,1979. for among other things, violation of water and air pollutionregulations, and odors. Hearings on the Order were held in Mayand June 1979., Also, the towns of Burrillville and North Smithfielddeclared tvi?t the Slatersville Aquifer had become contaminated bywastes migrating from the site. Six ground water monitoring wellswere installed by Western Sand and Gravel under a consent agreementwith DEM and tested during November 1979. Analyses of the samplesshowed the presence of toluene, xylene, chloroform, 1,1,1-trichloro-ethane, trichloroethylene, tetrachloroethylene and dichloromethane.In the same time period DEM issued a consent decree, a show causeorder on closure, and a final closure order for pumping the chemicalwastes from the lagoons.
In 1979, hazardous wastes were no longer accepted at the site.State industrial waste manifests were kept for materials depositedat the site from May 1978 to April 1979. The manifests showapproximately 470.000 gallons of waste deposited at the site curingthat one year period. The quantity of wastes deposited at the siteprior to May 1978 is unknown.
In March 1980, personnel from the EPA Environmental ServicesDivision, on request from DEM, pumped the lagoons and began removalof the hazardous material. It is estimated that approximately60,000 gallons of liquid materials were removed. These actionswere taken under the authority of Section 311 of the Federal WaterPollution Control Act. as amended.
In December of 1983. the ground water recirculation systeminstalled by thf State of Rhode Island in November 1982. withthe intent of controlling the migration of hazardous wastes fromthe site, malfunctioned, causing an overflow of between 50 and250 gallons of waste material from an underground 10,000 galloncapacity tank. The Rhode Island Department of EnvironmentalManagement immediately took action to clean up the spill anddisposed of the contaminated spill debris at its expense. DEMthen notified the EPA Environmental Services Division and requestedthat the Agency assess the situation. As part of the EPA assessment.
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samples of aqueous and non-aqueous materials from the undergroundtank were sampled. In addition, the Department of EnvironmentalManagement excavated and removed from the site twelve drums ofsoil that were contaminated because of the overflow and replacedone of the system's pumping wells. f
CURRENT STATUS
A. Quantity, Types and Concentrations of Hazardous Substances
The RI/FS for the Western Sand and Gravel site was conductedby Arthur D. Little, Inc. The exact quantity and types of wastedeposited at the site are unknown. In addition, it is not certainwhen hazardous wastes were first deposited there. Therefore, itis not possible to determine the maximum possible amounts of wastesdumped at the site. However, based on information provided by theRhode Island .Department of Environmental Management manifests,approximately 470,000 gallons of wastes were disposed of at thesite during 1978-1979, with a nonthly average of 36,000 gallons.
YEAR MONTH GALLONS
1978 May 10,000June 22,700July 5,300August 40,600September 52,500 ff.October 28,100November 23,100December 32,750
1979 January 51.400February 58,300March 63,800April 79,000TOTAL 467,750
A priority pollutant analysis of hazardous wastes in the lagoonsprovided the following information on the types and concentrationsof the substances present (results in ug/1 or ppb). Prior to thepumping out of the lagoons, they were sampled at the surface andthe bottom (sediments). Leachate run-off from the lagoons wasalso sampled.
Volatiles Surface Sediments Leachate(ug/1) (ug/1) (ug/1)
Methylene chloride 19,000 23,000 301,1-Dichloroethylene 340Trichlorofluoromethane 730 -1,2-Dichloroethane 1,2001,1,1-Trichloroethane 230,000 460,000 661,1-Dichloroethane 4 ,700 7,500 24Trichloroethylene 140,000 550,000 3
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Vjol_a_tJL_le_s (Cont . ) Surface Sediments Leachate
Benzene 69 970 171,1,2,2-Tetrachloroethylene 280,000 91.000 2Toluene 24.000 7,200 ^ 230Ethylbenzene 68,000 23.000 " " 13Chlorobenzene - - 2.8
Ac_id_s
o-Chlorophenol 540Phenol 9804-Chloro-m-cresol 1.000 1604,6-Dinitro-o-cresol 940
B_a_s_e Neutraljs
Naphthalene- 7,800 2,900Anthracene 1,600 360Pyrene 440 110.Fluoranthene 210 230Chrysene 490 170Butyl benzylphthalate 47,000 14,000 24
Detection Limits 10 42 0.2
B. Extent of Contamination
There are three primary sources of contamination at the WesternSand and Gravel site. These include the contaminated ground waterplume located primarily in the northwest quadrant of the site butextending in a northerly direction toward the Slatersville Reservoir.chemical sludges found in the unsaturated zone at several locationson the site, and non-aqueous phase liquids (not soluble in water)that are primarily in the area near the existing ground water"recir-culation system. It is estimated that 3.818 cubic yards ot sludgeand sludge contaminated soils remain on site, as well as 582 cuoicyards of contaminated surface material (contained within the surfaceareas to a depth of 6 inches) 1573 cubic yards of contaminatedsoil below the sludge in the unsaturated zone (these soils arecontaminated by the overlying sludge and less viscous materials),and approximately 17,000 cubic yards of contaminated soils locatedin and around the waste handling areas. These numbers werecalculated as follows (quantities were derived from the RI/FSunless otherwise noted and include a 30% contingency):
Sludge & Sludge Contaminated Soil
LOCATION YP_L_U_HE
Pit 11 (Area A in R I / F S ) 145Pit 2 (Area B in R I / F S ) 30Area C in RI/FS 233 (RI /FS)
plus addit ional GZA calculations 2210 ( G Z A )Area E in RI/FS 12_0_0TOTAL 3818"
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The RI/FS estimated a total of 1600 yd3 of contaminatedsludges. The Goldberg-Zoino (GZA) report estimates between 2000and 4000 yd3 total contaminated sludges. The GZA report appearsto be more accurate in its calculations for the amount of sludgeon site, as the GZA investigation done in support of the^reportincluded numerous test pit explorations in an area not able tobe investigated by the RI/FS contractor due to placement of theground water recirculation system. Based on the GZA report as asupplement to theRl/FS, the amount of sludge remaining on-siteis calculated to be 3820 yd3, which includes a 30% contingencyfor sludge-contaminated material located next to the sludges(hereafter referred to as the visibly contaminated soils).
SURFACE MATERIAL
' LOCATION VOLUME. <Y<i3)
Pit II 160Pit 2 22Area F in RI/FS 400
TOTAL 582
CONTAMINATED SOIL TO SATURATED ZONE
LOCATION . YP.LUME (yd3) /-
Pit 11 350 ^Pit 2 48Area C in RI/PS 1175
TOTAL Y5~73~
CONTAMINATED WASTE HANDLING AREAS
LOCATION VOLUME, ( y d 3 )
Area D in RI/FS 1,070Area G in RI/FS 17,000
TOTAL 18,070
The contaminated ground water plume is migrating in a northerlydirection and has intersected monitoring wells at depths rangingfrom 45 to 75 feet below ground level.
C. Pathways of Migration
The contaminants leaving the Western Sand and Gravel site aremigrating primarily via ground water and surface water. Contaminantsare entering drinking water wells, the Tarkiln Brook and the Siaters-ville Reservoir.
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The ground water flow in the area of the Western Sand andGravel site occurs principally in the unconsolidated deposits andin fractured portions of bedrock. Measured depth to ground waterranges from approximately 4 feet to 30 feet. The thickness ofunconsolidated material is variable beneath the disposal, site andgenerally parallel to the Tarkiln Brook. The lower portfibn ofunconsolidated deposits is slightly more permeable than the upperportion.
The contaminated ground water flow at Western Sand and Graveldischarges to the Slatersville Reservoir and Slatersville Aquifer.The hydrogeologic conditions downgradient from the site are suchthat this flow is partitioned with approximately 80% dischargingdirectly to the Reservoir and 20% recharging the SlatersvilleAquifer that ultimately discharges to the Reservoir (partitioningbased on an evaluation of the horizontal and vertical hydraulicgradients in areas adjacent to the Reservoir). The contaminantloading to the Reservoir is approximately 3 gallons per day ofvolatile organics, assuming a ground water flow of 9000 gallons/daywith a worst case volatile organic content of 410 ppm, based onmonitoring well observations. Based on modeling, the dilutioncapacity of the Reservoir in the area of the contaminated dischargewas estimated at 30 million gallons, yielding an effective concen-tration of 0.10 ppm of total volatile organics. The concentrationof specific chemicals would be appreciably lower. Approximately0.7 gallons per day of volatile organics would flow to the Aquifer,which in turn discharges to the Reservoir.
Estimates of hydraulic properties of the stratified drift onsite include hydraulic conductivity that ranges from 12 to 90 feetper day and porosity that ranges from 0.20 to 0.35. These incombination with hydraulic gradient estimates of 0.002 to 0.003yields a transport velocity range of 0.2 to 1.5 feet per day.
Test drilling results indicate that the upper portion of thebedrock is fractured and is a path for ground water flow. The--estimated hydraulic conductivity is one foot per day and porosityis 0.01 (1%) for the fractured bedrock.
D. Actual or Potential Affected Receptors
There are both human and environmental receptors that arecurrently or potentially exposed to contaminants migrating fromthe Western Sand and Gravel site. The primary receptors are theindividual residents downgradient fronv the site whose drinkingwater wells have already or may potentially become contaminatedwith hazardous chemicals. Currently, nine homes have showncontamination of private drinking water wells at least one timeduring their sampling history. The highest levels detected inthe private wells are within the National Interim Primary DrinkingWater Standards for noncarcinogens. However, the levels are inexcess of a 10~^ excess cancer risk. The levels detected andthe associated risk are as follows:
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Contaminant Level
1,1,1 - trichloroethane 6 ppb
trichloroethylene
tetrachloroethylene
1,2 - dichloroethane
1,1 - dichloroethane
dichlor onethane
5 ppb
8 ppb
21 ppb
2 ppb
18 ppb
10"6 Excess Cancer Risk
being investigated byEPA Cancer Assessment Groupfor carcinogenic properties
2.B ppb
0.9 ppb
0.95 ppb
carcinogenic propertiessuggested in animal studies
0.15 ppb - cancer riskbas d on chloroform, asuspected carcinogen
In addition, based on the extent and directional flow of theplume and monitoring observations, it is expected that more privatewells will exhibit contamination in the future* although (becauseof the nature of the subsurface conditions,i.e. a ground waterflow gradient down into fractured bedrock) it is difficult topredict precisely which of the existing and potential future wellsin the threatened area will actually become contaminated. It isalso difficult to predict how long a given well is likely to remaincontaminated. While the ingestion of contaminated drinking waterposes a current and future public health risk, the current andprojected use of the Reservoir indicates there is no acute orchronic public health risk associated with exposure to surfacewater in the Reservoir,
In the vicinity upgradient from the majority of residentialwells, yet within the contaminated ground water plume, is groundwater monitoring well G2-1. Because of the location of GZ-1, itprovides information on the horizontal and vertical extent ofcontamination and was used as an indicator well for possible futureimpacts on the residential wells.
Contaminant
1,1-dichloroethylene
1,1-dichloroethane
Level (ppb)GZ1-2* GZ1-3**
10
184
14
226
10~6 Excess DraftCancer Risk (ppb) SNARL (gpb^
carcinogneic proper-ties suggested inanimal studies
trans-l,2-dichloroethylene 398 202 275'
ff
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1 ,2-dichloroethane 2 - 0.95
1 ,1 ,1-trichloroethane 12 66 being investigatedfor carcinogenicproperties
chlorobenzene 23 64 2 0 ( ° )
benzene 10 38 0 .68
toluene 87 440 340
ethylbenzene 32 190
xylene 120 720 620
chloroethane 2
*GZl-2 is 45' feet below surface. **GZl-3 is 74 feet below surface***10-day EPA Draft Suggested No Adverse Response Levels (SNARLS)(HA) Health Advisory(°) based on organoleptic properties,
EPA Ambient Water Quality Criteria
Recent monitoring results from this well indicate an increasein the concentration of hazardous substances in the contaminantplume. It is believed that this increase will begin to bereflected as increased contaminant levels in residential wells.
Based on the available residential and ground water well datacoupled with the determined location and migration of the contamin-ated ground water plume, a threat to public health is determinedto exist, as evidenced by contaminant levels above the 10~6 excesscancer risk. In addition, in the absence of established formaldrinking water standards or maximum contaminant limits for the .substances cited in the table immediately above, EPA believes thatthe draft SNARL'S (prepared by EPA's Office of Drinking Water foradvisory purposes), although not enforceable regulations, provide areasonable indication that the levels of certain cbntaminants foundin well GZ-1 may be of concern. Even with complete removal of thecontaminant source, it would take at least 15 years and probablylonger for contaminant levels at GZ-1 to decrease to safe levels.
Direct contact is another route of exposure of concern at thissite. The site has been used for dirt biking and for pet runs, aswell as being in close proximity to the sand and gravel operationslocated on the property.
Other receptors include the biological flora and fauna found inthe Tarkiln Brook and S latersville Reservoir including pickerel,blue-gill, and bass living in the Reservoir. However, the quantitiesof substances released to the Tarkiln Brook are estimated to be
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below those associated with aquatic toxicity. In addition, smallgame including rabbits and squirrels have been observed in thearea and may be exposed to the contaminated waters of TarkilnBrook. The remedial investigation indicated that these speciesare not being impacted by the contaminated surface flow. The U.S.Department of the Interior (DOI) stated in its preliminiry naturalresources evaluation of the site that no lands, minerals, watersor Indian resources under DOI's trusteeship have been damaged byreleases of hazardous substances and that the current existingrisk to DOI trust resources is relatively low. Monitoring datafrom April 1984 indicate that concentrations of hazardous substanceswithin the Tarkiln Brook decrease with distance downstream, owingin part to dilution effects.
The five surface water samples collected (one up-stream fromthe site, two adjacent to the site, one in the swamp and one atthe confluence where the Tarklin Brook and Reservoir meet) representthe most recent surface water monitoring data. All samples measuredat non-detectable levels except for one sample taken adjacent tothe site. According to the RI/FS, the levels detected in thatsample do not pose an acute toxic hazard to aquatic and terrestrialspecies.
The levels of contamination projected in Tarkiln Brook and theSlatersville Reservoir do not pose an acute toxic hazard to aquaticand terrestrial species. Also, the concentrations of contaminantsdischarging to the Slatersville Aquifer are below any levels associ-^ated with immediate risk to flora and fauna.
ENFORCEMENT
On February 7, 1984, a meeting attended by 49 of the 91potentially responsible parties (PRPs) was held in Boston, MA, tobegin negotiations in order to determine whether any responsibleparty was willing and able to undertake remedial design andconstruction. Negotiating meetings were conducted with thesteering committee representing approximately 45 PRPs on March 20;April 11; May 3; May 16 and May 30, 1984. On April 4, 1984, EPAmet with a technical representative of the steering committee todiscuss comments on the RI/FS. EPA does know that 17 of the 20largest contributors (by volume) are represented by the steeringcommittee. A negotiation schedule was developed requiring theparties to ccmmit by May 30, 1984, their willingness to undertakethe remedy. On May 30, 1984, the PRPs made an offer and EPAresponded with a counter-offer requiring implementation of theremedy outlined in this document and repayment of most post-CERCLAexpenditures. In light of the imminence of settlement anddelay in the ROD briefing from June 14 to June 25, EPA extendedits negotiation deadline until June 15, 1984. On June 22, 1984,the PRP's offered the agency a cash settlement of approximatelyS2.23 million, representing 80% of the Agency's costs. Thisoffer was rejected because a cash-out settlement posed unacceptable
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financial risks, because the proposed settlement would leave 20%of EPA's costs unreimbursed with few viable KlP's remaining topursue.
ALTERNATIVES EVALUATION
Based on the findings of the remedial investigation and riskassessment, the following response objectives were identified:
1) To provide residents in the affected area with a per-manent supply of safe drinking water,
2) Abate local sources of contamination at the site;
3) Minimize future public health risks by restrictingsite access.
There were twelve alternatives considered in attempting to meetthe above objectives. These remedial alternatives were developedby combining off-site components for a permanent water supply andon-site components for contaminant source reduction and site closure.The twelve alternatives include:
1. No action.
2. Off-site water supply only.
3. Permanent relocation only.
4. Off-site water supply, limited capping, fencing,grading, seeding, learning and monitoring.
5. Off-site water supply, full capping, fencing, grading,seeding, loaming and monitoring.
6. Off-site water supply* on-site landfarming, encapsulation,and/or landfilling of sludges and visibly contaminatedsoil, fencing, grading, seeding, loaming and monitoring.
7. Off-site water supply, limited excavation and off-sitedisposal of sludges and visibly contaminated soil,fencing, grading, seeding, loaming and monitoring.
8. Off-site water supply, Area E excavation and off-sitedisposal, fencing, grading, seeding, loaming and monitoring.
9. Off-site water supply, limited excavation and oft-sitedisposal of sludges and visibly contaminated soilincluding Area E, fencing, grading, seeding, loaming andmonitoring.
-11-10. Off-site water supply, total site excavation and off-site
disposal of sludges and visibly contaminated soil,fencing, grading, seeding, loaming and monitoring.
11. Off-site water supply, limited capping and limited 'excavation and off-site disposal of sludges arid visiblycontaminated soil, fencing, grading, seeding, loamingand monitoring.
12. Off-site water supply, limited capping and limited Area Eexcavation and off-site disposal of sludges and visiblycontaminated soil, fencing, grading, seeding, loamingand monitoring.
In accordance with Section 300.68(g) of the National ContingencyPlan (NCP), these alternatives were developed considering both sourcecontrol'and off-site remedial actions. The alternatives were basedon the results provided in the remedial investigation which determinedthat contaminants are migrating off-site via ground water and havealready impacted nine drinking water wells. (The RI/FS determinedthat seven residences in the affected area have shown contaminationin their drinking water. Discussions between the EPA RegionalSite Manager and the Rhode Island Department of Health, after theRI/FS was completed, confirm that as of May 1984, nine homeswithin the affected area have shown contamination in their privatedrinking wells.)
The initial listing of the twelve remedial systems can best beclassified by evaluating the components of each system according toon-site and off-site remedies.
Off-site components investigated include:
A. No action.B. Permanent relocation of residents.C. Permanent drinking water treatment
(carbon filters, bottled water).D. Permanent alternate water supply.E. Treatment of the contaminated water using the
existing groundwater recirculation system.
On-site components investigated include:
A. Contaminant Source Reduction/Control
1. No action2. Capping3. Landfarm/encapsulation4. Excavation and off-site disposal
a. Limitedb. Total site
5. Existing groundwater recirculation system
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6. On-site Landfi l l ( in compliance wi th RCRA)a. Limitedb. Total site
B. S ite Closure
1. No action2. Fencing3. Grading, learning and seeding4. Monitoring5. Capping
The components of the twelve remedial systems were screenedaccording to the requirements of Section 300.68(h) of the NCP inorder to narrow the list of potential remedial actions for furtherdetailed analysis. The criteria used in the initial screening processincluded: 1) total system costs, considering net present value ofcapital and O 'and M costs; 2) effects of the alternative upon the.environment with evaluation of whether the alternative will achievesource control and mitigate threats to public health, welfare andthe environment; and 3) acceptable engineering practices withrespect to feasibility and reliability for addressing the problem.
The initial screening of the off and on-site remedies resultedin excluding the off-site option of no action. Considering thecriteria (i.e. mitigation of the threat to public health) foreffects of the alternative, this option was screened out based onthe fact that certain wells are now contaminated at levels ofconcern, and that there is a reasonable expectation that contamin-ation will appear in additional wells located between the site andthe reservoir. A representative sample of contaminants identifiedin private drinking water wells at "levels of concern" includes:1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene,1,2-dichloroethane, 1,1-dichloroethane and dichloromethane. Basedon sampling from upgradient wells these levels are likely to increase.
The reason for consideration of permanent relocation of resi-dents located within the affected area is based solely on publichealth concerns related to the present and potential ingestion ofcontaminated drinking water from the private wells. The cost ofpurchasing the 56 parcels of land, which now show or may in thefuture show ground water contamination, at fair market value is$3,310,000. The public health problem of ingesting contaminatedwater can be more cost-effectively abated by installing an uncon-taminated alternate water supply for §1,200,000. The cost ofrelocation was evaluated against only the cost of the installationof an alternate water supply because the public health concern wasbased solely on the ingestion of contaminated drinking water fromthe private wells. Therefore, the off-site option for permanentrelocation of residents in the affected area for public healthconsiderations can be eliminated on the basis of cost.
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Treatment of the contaminated ground water off-site using theexisting ground water recirculation system was omitted as an optionbased on the determination that the system will not mitigate thethreat to public health caused from ingestion of the contaminatedground water. A portion of the plume has already migrated off-site,contaminating nine private drinking water wells. While.:such asystem may help retard contaminant migration from the site, theexisting systetn would not pull back the contaminated groundwateralready downgradient front the site or restore the contaminatedwells. Without such restoration, current and future threats topublic health from ingestion of contaminated drinking water wouldnot be mitigated.
Several on-site remedies for contaminant source reduction/controlwere also excluded from further consideration during the initialscreen. The no action alternative was excluded using the criteriafor effects of the alternative, based on the fact that no actionwould not achieve source control. Based on the results of theremedial investigation and risk assessment, a continuing source ofcontamination would provide a threat to public health from potentialdermal exposure. In addition, in reviewing site conditions todevelop a natural resources survey, the U. S. Department of theInterior has determined that in the absence of remedial action,there is a definite potential for future damages. The continuingsource of contamination would result in adverse environmental- effects,in that the sludges left on-site could cause degradation in surfaceand ground waters and lengthen the time necessary for the Slatersvi]^—Aquifer to cleanse itself.
vThe landfarming/encapsulation options were excluded from
consideration because the technologies are considered to be unprovenwith respect to treating the types of wastes found in the soils atWestern Sand and Gravel and, therefore, did not meet the criteriafor acceptable engineering practices.
The existing groundwater recirculation system was excludedfrom consideration as a long-term on-site option for contaminantsource reduction/control based on effects of the alternative. Aspreviously stated, regarding its impact on public health, operationof such a system would not improve the water quality in already-contaminated private drinking water wells. The system has provensomewhat effective in capturing non-aqueous phase liquids floatingon the groundwater surface.
The HI/PS predicted that removal of the recirculation systemcould permit any remaining non-aqueous phase liquids to migrate ina northerly direction until intercepted by the Tarkiln Brook.Should this occur, projections indicate that there would be noadverse acute toxic effects on aquatic and terrestrial life fromthe nonaqueous material, as it is suspected that most of the non-aqueous layer has already been removed from the groundwater surface
/Wli
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and stored in an underground tank. This estimation that most ofthe non-aqueous phase liquids have already been removed is basedon observations that the system has been capturing non-aqueousphase liquids at a rate much below that experienced during 1982and 1983. A . • .
The on-site alternative of no-action for Site Closure was alsorejected, because closure provisions are necessary to adequatelyprotect public health and the environment from future migrationfrom this site.
Consistent with Section 300.68(i) of the NCP, the off-siteand on-site remedies remaining after the initial screening wereincluded in a detailed evaluation. The detailed analysis of eachoption included:
1. Description of appropriate treatment and disposal• technology.
2. Special engineering considerations (pilot plant,additional studies).
3. Environmental impacts of proposed methods.
4. Operating, maintenance and monitoring requirements.
5. Off-site disposal needs and transportation plans.
6. Temporary storage requirements.
7. Safety requirements for remedial implementation on-siteand off-site.
8. Description of how the alternative could be phased intooperable units. - .
9. Description of how the alternative could be segmentedinto areas to allow implementation of differing phasesof the alternative.
10. A review of the off-site facilities provided by thestate to ensure present and future compliance with RCRA.
11. Environmental risk assessment.
12. Cost analysis - total costs including operating andmaintenance.
13. Reliability of the system.
14. Implementability at the site.
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The remedial components 'considered after the initialscreening are listed below:
Off-site
"Permanent limited water supply system (bottled water).
•Permanent alternate water supply.
•Permanent drinking water treatment for total home use (filters)
•Temporary drinking water treatment for total home use (filters)until the permanent supply is functional.
•Temporary alternate water supply (bottled water) until theperroananent supply is functional.
On-site .
•Removal of existing recirculation system.
•Soil and sludge excavation and on-site RCRA Landfill.a. Limited (3,820 yds3)b. Total (24.000 yds3)
•Soil and sludge excavation and off-site disposal at A RCRA ^facility.
a. Limited (3,820 yds3) \^b. Total (24,000 yds3)
•Capping.a. Limitedb. Total (400,000 ft2)
•Site Closure.- Capping- Fencing- Grad ing , Loaming, Seeding
•Ground water monitoring consistent with RCRA requirements.
In the course of the assessment of on-site alternatives, EPAdetermined that existing sampling data on the location of thesludges, concentrations of contaminated material below the sludges,and the extent to which those areas were subject to ground watersaturation on a seasonal basis were insufficient to permit finalselection of a remedy. Therefore, the decision for on-siteremedies is being deferred pending the development of additionalcontamination and ground water data. The remainder of this RODaddresses off-site actions only.
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RF.COMMENDED ALTER NATIVE
The reconunended off-site alternatives for the Western Sandand Gravel Site were selected in accordance with the NCP- partic-ularly Section 300.68 (j), and was determined to be the nfostcost-effective alternative that adequately protects and mitigatesdamage to public health, welfare and the environment.
A. OFF-SITE ALTERNATIVES
In considering the off-site options for a potable watersupply, the alternative of a permanent alternate water supplywas determined to be the most cost-effective long-term remedy.The areas to be provided with an alternative water supply havebeen determined as follows. First, water would be provided tonine parcels where wells have demonstrated contamination todate. Second, there are 47 other parcels of land located betweenthe source of contamination and the reservior, and in the generalarea where contaminated wells have been found. It is expectedthat at least some of these wells will show contamination in thefuture, and that contamination would continue for some time. Itis impossible, however, to reliably identify which particularwells will be contaminated. If EPA did not provide alternatewater for these parcels at this time, it would be necessary tosample the wells periodically and if contamination were found inthe future, to consider extending alternative water supplies atthat time. Although EPA has not specifically analyzed the costsof long-term monitoring of the potentially affected area andextending alternative water on a piecemeal basis, it is believedthat it would be more efficient to provide alternative water tothe entire potentially affected area at one time. In addition,extending water now would reduce the risk that persons may beexposed to contamination before periodic sampling could detectthis contamination. The estimated present worth cost for provid-ing a safe drinking water supply through an alternate system is.51,200,000. The estimated cost for individual carbon canisters(total home use) is 5156,800 for 56 units for the first year,including capital and O & M. Yearly O & M after the first yearis $100,800. Therefore, in 11 years, the cost of filtrationunits would be approximately the same as the cost of a permanentalternate water supply. Starting the 12th year of filtrationuse, that system would become increasingly more expensive thanthe other permanent alternate water system. The same costargument is true for bottled water, estimated to cost $95,200per year to supply 56 parcels. In 12 to 13 years, the cost ofusing hottled water for drinking purposes only and not totalhome use would exceed the cost of the permanent alternate watersupply. Therefore, an alternate water supply providing uncontam-inated potable water for total home use to 56 parcels is themost cost-effective long-term solution.
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The installation of an alternate water system has beendetermined to be the most cost-effective long-term method toabate the current and potential public health risks associatedwith ground water contamination. The cost of the system providesfor water to the tap for all home uses for 56 parcels and forfire protection. Fire protection capacity was calculated ascomprising 4.2% or approximately $50,000 of the total cost ofthe alternate water system. Because the cost of fire protectionis such a small percentage of the cost of the total system andwould offset some of the maintenance required system costs (i.e.flushing valves), it is recommended that it be a component otthe alternate water system.
Once it was determined that an alternate water system wasthe most cost-effective option for the provision of potablewater, locations and availability for the alternate supply wereexplore'd:
EVALUATION OF ALTERNATE WATER SUPPLY LOCATIONS
SYSTEM
1. Slatersville
2. Industrial
3. Nasonville
4. Slatersville/IndustrialTie-in
5. Well Field A
6. Well Field B
7. Well Field C
EVALUATION
-inadequate capacity as solesource
-inadequate capacity as sole 'source; currently used torindustrial purposes and one of x
the two wells is high in iron
-inadequate capacity as solesource
•adequate capacity but local -institutional constraints makeit unavailable
-adequate yield and upgradientfrom the site; close to theaffected area
•close to the affected area withadequate yield, but may possiblyhave future contamination fromthe W5G site
-close to the affected area withadequate yield, upgradient fromWSG but downgradient from Landfilland Resource Recovery, a nearbyNPL site, so there is a potentialfor future contamination
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/lii
8. Area by Tarkiln Pond -close to the affected area withadequate yield and upgradientfrom WSG; recommended by localcitizens involved with localwater systems - -
Water Systems 1, 2, and 3 were eliminated as alternative watersupplies because of inadequate capacity. Water Systems 4 through8 have adequate capacity. System 4 is unavailable because ofinstitutional constraints. Systems 6 and 7 could potentially beimpacted by contamination, and would require additional investigationbefore they could be utilized.
Water systems 5 and 8 are acceptable because 1) both haveadequate capacity; 2) both are located within the town of Burrill-ville and therefore eliminates the politial constraints encounteredwith water sources located outside of the town and 3) the TownCouncil of Burrillville has a mechanism for land acquistion, ifnecessary, to obtain land for a wellfield.
The costs for water systems 5 through 8 are approximatelyequal. The only difference between the systems is the locationof the production wells. The final selection of the well locationwill be based on technical criteria developed during design.-
As previously stated, the contaminant levels in the domesticdrinking water wells do not exceed the recommended levels fornon-carcinogens prescribed by EPA. However, some of the chemicalsdetected in these wells are suspect carcinogens. The measuredlevels and associated 10~6 excess cancer risk are as follows:
CONTAMINANTHIGHEST LEVELS OF SUSPECTCARCINOGENS DETECTED IN PRIVATE WELLS
10~6 EXCESSCANCER RISK
trichloroethylene
tetrachloroethylene
1,2-dichloroethane
6 ppb
8 ppb
21 ppb
2.8 ppb
0.9 ppb
0.95 ppb
It is reasonable to assume that these low-levels of carcinogenshave been ingested for some time and adverse health effects fromsuch long-term low-level exposure is unknown. In addition, it isappropriate to take preventive public health measures when anexcess cancer risk greater than 10~6 is determined. Therefore,it is a prudent preventive public health measure to providetemporary clean potable water to those residences exhibitingcontamination.
. -19-
While carbon canister filters and bottled water weredetermined not to be the most cost-effective options for long-termpotable water, it is recommended that filters be used as theinitial remedial measure for those homes with contaminated wells/until the permanent water supply is functional. In the-event thatmonitoring results show contamination above an acceptable levelfor additional residences in the affected area, filters will beprovided.
The costs associated with providing carbon canisters fortotal home water use (bathing, drinking, etc.) for nine homes(including operation and maintenance) for one year is $31,500/yr.The cost for providing bottled water for drinking purposes onlyand not total home use is $13,600/yr. for 9 homes. Due to thewide range of chemicals present in the plume, it is not certainthat ingestion is the only possible route of exposure. To protectagainst the possibilities of inhalation and dermal exposure, itis recommended' that protection for the total home use of waterb«- prr\-:^e3. T^-rrfore, it is recommended that the homes withcontaminated drinsing water wells be provided with carbon canisterfilters as an initial remedial measure until the permanent watersupply is functional.
The recommended alternative includes:
Remedial System Present Worth
1. Permanent water supply $1,200,000to 56 Parcels
2. Temporary water supply (filters) 51,750for 9 homes until permanent watersupply is functional (2 yrs)
SUBTOTAL $1,251,750
15% CONTINGENCY 167,763
TOTAL COST $1,439,513
COMPLIANCE WITH OTHER ENVIRONMENTAL LAVS
The permanent alternative water supply and the temporaryfilters will assure that persons in the area potentially atfectedby contaminated ground water will be provided with water which meetsthe standards of the Safe Drinking Water Act.
GROUND WATER PROTECTION
The RI/FS indicates that even with source control measuressuch as capping and soil removal, which will be addressed in asubsequent ROD, ground water in the vicinity of the site wouldremain contaminated for some time in the future.
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The recommended remedy will abate the most immediate andI significant public health risk from contaminated ground water.v In addition, however, the Agency will also consider the need for
either corrective action to address the remaining contaminatedground water. The Agency currently lacks sufficient dat£ todetermine the proper course of action for the ground water at •this site. A final decision on the necessity and feasibilityof ground water treatment at this site will be made upon thecompletion of additional study. The need for further soilexcavation will also be evaluated as part of the cost-effectiveanalysis of ground water treatment.
SCHEDULE
I
ACTIVITY
- Approve Remedial Action (ROD)
- U.S. Army Corps of Engineers beginsselection and procurement processfor engineering design services
- Award Superfund state contract andissue IAG for design and construction
- Amend cooperative agreement
- Award design contract, start design
- Complete design ofPermanent water supply
- Start construction ofPermanent water supply
- Complete construction ofPermanent water supply
DATE
September 1984
September 1984
September 1984
September 1984
December 1984
September 1985
November 1985
August 1986
COMMUNITY RELATIONS
EPA released a draft feasibility study (FS) to the publicthe week of January 30, 1984. Press releases, paid newspaperadvertisements, and direct mailings to about 90 persons were usedto announce the availability of the document, the comment period,and two public meetings.
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EPA held a public meeting on February 2, 1984, to explainthe recommendations of the FS, and another meeting, on February 23,to accept community comments on the F5 . Both meetings were heldin the local community. EPA, the State, and State's consultant,media representatives, citizens, local officials, and Cengressionalsattended. Between 50 to 100 people were present at each meeting.
The written comment period was initially announced to runfrom February 2 until February 23, and later extended by EPA toFebruary 29. Citizens then requested the comment period beextended to March 15. EPA compromised and extended it untilMarch 7. Several comments were received shortly after the lastdeadline. They have been included in this summary.
The majority of the comments came from the Western Sand andGravel Coordinating Committee, and advisory committee formed in1981 by the Burrillville Town Council, at the request of the RhodeIsland Department of Environmental Management (DEM), to facilitatecommunication between DEM and local government and to review plansand provioe acvice to DEM.
The Committee's recommendations were endorsed by the NorthSmithfield and Burrillville Town Councils, the North SmithfieldConservation Commission, the Burrillville Health officer. StateSenator Elizabeth M. Cesario, and two individuals.
SEP 28 BB4
COMMUNITY RELATIONS RESPONSIVENESS SUMMARY
Western Sand and Gravel Superfund Site * •
Introduction
The responsiveness summary will describe citizen concerns
raised during the coment period on the feasibility study and how
EPA considered and responded to these concerns.
In addition to the public meetings, EPA and DEM met informally
with the Western Sand and Gravel Coordinating Committee twice
during the comment period to ansver questions about the proposed
remedial action and to heat the committee's concerns.
DEM commented on the FS at the February 23 public meeting.
Those comments, which recommend modifications of the remedial
action recommended by the FS , are listed separately.
Comments from the generators* committee fthe Western Sand
and Gravel Steering Committee) have also been listed.
_f contaminated soilsuggestions'ranged from 16,000cubic yards to "remove all toxicwaste." Western Sand and GravelCoordinating Committee (V6GCC)recommended removing "20,833cubic yards or all sludge andcontaminated soil." Also wantexcavated areas filled withclean fill.
6 Need for public water supply;VBOCC and several others enphaticallysupported this FS recommendation, withstipulation of free tie-ins and feesonly for usage.
a o n sy^temt^as long as n
Ground water recirculationwant system continued as long as non-aqueous liquids remain, skimming ofnon-aqueous liquids, and additionalpumping wells near areas A and B,and between areas C,D, and E and thebrook (recommendations of VBGCC andan individual). Another contentrecommended expansion of the systemto "remove the 'source ' of the plume.1
ERA RES tOtSE
• After further evaluation of theamount of contaminated soils and sludgesremaining on site, the Agency recommendsthe deferral of on-site remedies pendingthe development of additional ground waterand contamination data, To determine moreprecisely what contaminants needs to beremoved, and what can safely be containeden-site.
0 EPA agrees that a permanent alternate watersupply should be provided to residenceslocated in the affected area.
0 Data indicates that the ground water recircu-lation system has not been effective instopping migrat Ion of contaminated ground waterfrom the site find its usefulness in capturingthe ncn-aquecus liquids appears to be declin-ing. Therefore, ERA does not support longterm operation or expansion of th* System.Rather, the Agc'flfcy expects that the systemwill be shut drvti &nd removed In coordinationwith the eourci control actions to be selectedin a subsequent: ROD.
III.
Location of jrfater supply source;Several ccnroenters sugest specificwater supply sources. V6GCC recommendedestablishing a new domestic well upgradientof the site, and criticized the recommendationto use Slatersville Water System as source;they believe the Slatersville Reservoir hasinsufficient capacity, and may be subject tocontamination from the site and industrial ordomestic waste entering Branch River.
• Monitoring? V6GCC recommends 25 years or untilsteady decline for five years: include surfacewater from Tarklin Brook, swamp near SlatersvilleReservoir, the Reservoir itself, test wells andprivate wells. Supported by two individuals.
Ground water treatment! VBGOC endorses ground watertreatment and suggests a facility DEM had proposeedin 1981. Supported by three commenters.
0 Based on widespread citizen concern re-garding the location ot the supply source,RRA reevaluated the recommended source,the Slatersville - Industrial Tie-in, asprovided in theRI/fS. Further in-depthdiscussions with hydrologists, regardinglocations recommended by the citizens,have resulted in the Agency recommendingthe location of the water supply be withinthe Town of Burrillville and in the vicin-ity south of the site.
• EPA agrees that a monitoring program,including ground water and surface watersampling, should be conducted. Privatewells are also to be sampled according toa monitoring plan. The Agency i» consid-ering a monitoring program to be conductedfor a period of: 30 years in accordancewithR(RA Part 264, with provisions forreevaluation in five years after siteclosure.
• The installatim of a permanent alternatewater supply will abate the current andfuture public health problems associateswith ingestion of contaminated drinkingwater. However, in order to ensureadequate long terra protection of publichealth 6 the environment, ERA will furtherevaluate the nt>ed for additional remedialactions. Therefore, an additional studywill he conducted to further explore thetechnological feasibility ot ground watertreatment.
riIV.
if additional soil is excavate,*6GCC" believes fencing will be necessaryonly around the recirculation system.
Warning signs; W5GCC and another comentersupported this FS recommendation of placardsaround site perimeter.
° Property buy-outt requested by two individuals.
* Protection/cleanup jrf Slatersville Reservoir!one commenter requested EPA^remove the heavyoily layer which floats on the water." VBOCCendorses applying EPA drinking water qualitystandards to reservoir.
0 The Agency expects that the final source controlalternatives will include placing a fence aroundthe area where the pits and lagoons were located(9.25 acres) in order to restrict site accessand subsequent further use of the area.Restricting site access also serves as a preven-tive public health measure in protecting personsfrom dermal contact with any remaining contam-inated soils.
9 The Agency agrees that placards should be placedaround the perimeter of the site, as well as atthe brock, swamp and mouth ot the reservoir.
0 The Agency believes that providing a potablesource of uncontaminated water is the cost-effective measure for mitigating the public healththreat posed by the presence of contaminated ground water.The Agency believes that property buy-outs are notwarranted at tins site as there are no significantadverse public health effects which are not addressedby the recommemted remedy.
0 The citizens voiced concerns that there waslimited sampling data on the reservoir. Inresponse, DEM conducted a round ot surfacewater sampling, including the reservoir, inApril 1984. Ttf? monitoring data from the mouthof the reservoVr indicates that there is neitheran environmental nor public health risk associa-ted with any c«itamination of the reservoir(latest resevo'c sampling was below detectionlevels for any contaminants). i.
V.
Aquifer protect ion t WGCC endorsesapplying EPA drinking water qualitystandards to aquifer.
0 Contaminated ground water has alreadymoved otf-site to the downgradient neighbor-hood and reservoir. However, a study tofocus on the technological feasibility otrecapturing thnt part of the escaped plumeand treating it will be conducted.Installation ot* a clean permanent watersupply will abate -any present public healthproblems associated with drinking con-taminated water from wells located in theaquifer.
REMAINING OOWUNITY OONCFRfG
Tanporary point-of-use-water treatment tadvocated by V6OCC. Want carbon filtrationsystem and free installation and maintenance.
0 On reevaluatiny the homes determined to havecontaminated private well water, ERA supportsproviding temporary water supply treatment(for total hone use) to nine residences thathave exhibited contamination at least once intheir sampling history.
VI,
STATE COMMENTS EPARESFOtGE
0 Permanent water supply to60 "land parcels.
0 Temporary water supply toIndividuals with contam-inated water.
0 Removal of 1600 to 500 cubicards of contaminated soil.ncluding pit 13, l>lus con-
tingency for more removal.Make determination based onfirst excavations.
Tvo year minimum for phase-outof
JflTOh
system. Phase-cut not be doneuntil non-aqueous layer contam-inants no longer removed oruntil permanent water in place,if no temporary water provided.
'Looming and seeding of lagoonarea, in addition to sitegrading.
Fencing; agree with this F5recommendation for fencingperimeter of site.
Warning signs around perimeterof site and at brock, swamp, andmcuth reservoir.
Monitoring program to includewells, brook, swamp, reservoir,and continue until "sustainedand substantial" decrease incontaminants.
The State comments concerningalternative water supplies havebeen addressed in the body of theRecord of Decision. In addition,a number of comments weresimilar to community comments;see previous "Community Comments"section for specific responses.
VII.
GENERATE* COMMENTS EPA RESPONSE
• Public Water supply;
1. Need not supported by R I/PS. 1.Study does not present sufficientdata to support finding that siteposes a present or potentialthreat to public health. Modelthat was used to predict healthrisks not useful for makingpredictions of contaminants levelsat sane future point in time forestimating health risks.
2. ^xtert of "affected" area rver- 2.stated. Includes three domesticwells on Douglass Pike. "Highlyunlikely" that site is source ofcontamination in those wells.May have been frcm domesticdisposal or septic tank cleaners.Affected area should be redefinedbased on contours of grcundwaterplume. Size is 1/3 to 1/2exaggerated.
3. Estimated water demand of 500,000 3.gal/day exaggerated. 25,000 gal/daymore than adequated to supply affectedarea. No CERLCA requirement thatremedial action provide benefits beyondthose necessary to mitigate andminimize damage to public health andthe environment; therefore, noneed for fire protection capability.
4. Not shown to be "feasible for the 4.location" as required by NationalContigency Plan. Determination offeasibility requires thorough analysisof available water sources for thatwater supply system.
The basis for EPA's conclu-sions on threats due to con-taminated ground water isdiscussed in the ROD.
Although the precise extentof the plume is difficult todefine, EPA has a reasonablebasis for including theDouglas Pike wells.
The size of pipes used inthe system is based on standardtechnical considerations,not on alleged exaggerateddemand projections. Includingfire protection as part of thealternate water system increasesthe cost of the system by only4.6%, as discussed in the ROD.
After analysis, EPA has determinedthat there are several availablewater sources for the alternativewater supply system.
Vlii
3. Removal of Contaminated soil;recommended off-site disposal400 cubic yards, and site grading.
6. Fencing; recotrrend fencing, butdo not specify area.
Monitoring; long-term monitoringnot cost effective; if permanentpublic water supply is installed,threat will have been eliminated.
Point-of-use water treatment;reconrvend for "those domesticwells that have exhibited con-sistent levels of contamination,"(three at present). Rationale fordismissing this option was notpresented inRI/B.
Phase-out of ground waterrecirculation system; recommendedbut time frame not specified.
5. It is EPA's judgement thatremoval of all the mostheavily contaminated soilis necessary to protectagainst continued groundwater deterioration.- Basedon the contractors estimate,it appears that the amount ofhigly contaminated wastes isconsiderably greater than 400cubic yards. This estimatewill be finalized afteradditional data is developed.EPA believes that unless allcontaminated soil is removed(which would probably not becost effective) site cappingwould be a necessary part offinal closure of the sites.
6. Discussed in ROD
7. Monitoring will be addressedin a subsequent ROD. Long-term monitoring, con-sistent withRCRA Part 264,is necessary and appropriateto ensure that the source controlmeasures which are selectedare and continue to be effective.
8. Discussed in ROD.
9. EPA agrees with this connvent.This issue will be addressedin a subsequent ROD.
