Document 3JKQ7ZvNX1njx3pNj4DX6RY1E

***>*!cjriai3e*3Eirj AR226-2539 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION III 841 Chestnut Building Philadelphie, Pennsylvania 19107-4431 In reply Refer to: 3HW90 May 5, 1997 DAIS ENVmONMSNTAl CERTIFIED MAIL RETURN RECEIPT REQUESTED W.M. Stewart Sr. Environmental Control Consultant DuPont Washington Works P.0. Box 1217 Parkersburg, WV 26102-1217 Re: Notice of Deficiency Verification Investigation Report Washington Works WVD 045 87 5291 , Dear Mr. Stewart : The Verification Investigation, E.I. du Pont de Nemoures & Co., Washington Works (Report), dated April 1992 has been reviewed and, although the Environmental Protection Agency (SPA) finds deficiencies in the Report, sufficient information is included to warrant proceeding with the EGRA Facility Investigation (RFI). Therefore, a RFI work plan is due within 90 days of receipt of this GENERAL COMMENTS Enclosed is a table identifying deficiencies in the Report. While the comments are written as though the Report is to be revised, EPA is not requiring that the Report be revised. It is considered more important to proceed with the RFI than expend resources revising the Report. However, the items (in the table) in bold do need a response. Please provide a response within 30 days of receipt of this letter. It is difficult to locate the precise locations of sampling points using the Report's Figure 6. The Report contains a divider marked "Plates" but that section is empty. Please provide three copies of the plate locating the actual sampling points on the Celebrating 2 5 Years o f Environm ental Progress CF032526 EID481623 }) topographic map used in the Verification Investigation Plan, Page Permit Requirement Corrective Action Permit Attachment 1 required soil and groundwater analyses for inorganics, volatiles, andsemi^volatiles Tnvestigation Plan, Table 18 liited the e IA Ckniitituwit List bui ?mitted chromium. EPA's September 30, 1 9 9 1 SSlvsiS S l" 6* re^ ired surficial soil sampling d ^ a d Landfill and referred to parameters T a M odioHv,tiie which includes chromium. DuPont modified Table 18 but added chloride instead of chromium. acceptance?^TMficaUy i d e S t i f a i S ^ t eDOTthii c S & L ^ d "" 01-' Tta failed^ & aMl y S r i f 0^ U * Po,S : S 1TM t=lent and additioBal " * * * -- Groundwater Section 7.1 discusses the use of dissolved versus total metals when evaluating groundwater quality. The second paragraph A o S i d f ? 1!? Para raS5S the reffenced EPA Directive submittSd in Appendix P. The EPA Directive, upon which is based t-he 12okinJ9 at disslved metals concentrations only nbeettJwleeenn tthhee' etitr^A filtered hained-tournifi^lteirnefdormdaattia,on asnhdowshiaihncoinsTMiisteen_c,y aluminum are present in the unfiltered data, only filtered samples Salvsefleen information ^ S has aluminum b ?n ^ e l u d e d m previous or present sample analysis. In ari1-mSddvt"e"ih1i sa]ifling logs indicate that almost all wells are muddy, thick muddy," or have "medium to high turbidity." s a m p l ^ r f S f b i T ^ tL with reePect to metals when the Sa ^-ffionit* The practice is tending to total medals, or unf iltered samples/ often usina low-flrM* j__ techniques. Redeveloping g r o S w a t e i ^ n i S r i M sampling with low-flow t a o h n i q j e e TM i a ^ c T ? a l L s lite=tti e v S Und"at`r PBt,Ctl,i" st" d d in 40 CPR 264 S4 to ? Therefore, no metal may be eliminated from further consideration at this time. tohnee RKiivteernrabnSj*c 'LLanSdffinll, the AnaCe"r0obic TDRiIgTeOsEt*i,onfouPnodndsin waenldls^at 'Burning Grounds, are not 40 CPR Part 264, appendix S cone " events Celebrating 25 Tears o f Environm ental Progress CP032527 EID481624 3 and p^Ls MCLs assigned to them. toxicological information. PAL Please provide known ' T^e Report uses EPA proposed action levels (PALs) (July 27, Z ' ' f o r screening purposes, a more current list used by Region f f Re9^oa 111 Risk-Based Concentrations: R.L. Smith UiJ1?9 the residential exposure scenario for soils. The significant difference between the Region III table and the Report Table 4 is arsenic. The value in Table 4 fails to consider arsenic as a carcinogen. As reported values for arsenic in the soil exceed j??lon / ^ numberi it may be necessary to determine a site- specific soil arsenic background number. Background Soil Samples . Determination of inorganic, soil background levels becomes important when the inorganic constituents exceed the Region III S S * 8"??*! /?0"cetfations. Soil arsenic levels exceed the ndutrial values for arsenic as a carcinogen of 0 .43/3.8 mg/kg. A statistically valid determination for background levels of arsenic is needed. A one-sided tolerance levels is appropriate. .we2re taken to represent background inorganic constituent conditions. Seven samples is less than the minimum number generally required (eight samples are generally necessary to calculate an upper tolerance level to represent background) but more importantly, the background samples need to be from the same soil series and horizon as the samples taken to evaluate releases from a solid waste management unit, in addition, background soil samples must be taken from areas unimpacted by facility operations Inclosed is a copy of EPA's Engineering Forum Issue paper, Determina.tion of Background Concentrations of Inorganics in Soils and. Sediments at Hazardous waste Sites, EPA/540/S-96/500, December 1995. The paper identified some of the concerns in determining inorganic soil background levels. M EVALUATION OF RECOMMENDATIONS Polyacetal Waste Incinerator The Work Plan specified soil analysis for cadmium, chromium, lead, selenium, ra-Cresol, and phenol. The Report, Table 3, fails datarOVlde re0ults for and m-Cresci. Provide the missing Celebrating 25 Y ean o f Environm ental Progress CF032528 EID481625 Local Landfill 4 unacceotableSriwn investigation" recommendation may be S r I f s f s! S groundwater protection standard of 40 s `*64,94 18 exceeded for arsenic, barium, and lead. c l o s e ? d o iJe ^edoodiittroinoail iglro!un-d^w^at^erthmonLiotcaolring well wwaass bheeiinnSg lSdf^ 199? DuPont notified EPA that thl SalLand^ M TM Provide the regarding closure of the surface i ^ o S d m e ^ t Ca^Chedule P lans Riverbank Landfill , whileA mSS?'aj S CngliS e J ^ x) aeed to be performed Sd groundwater elevations. .^So/Jrsenic e with respect to 60 days of receint of please submit a report, within 2w r ^ s ^ S a r = = - Anaerobic Digestion Ponds Che " " * i U y located within s S S IIlP S It ?investigation to date wtt'hin o^.ipt J S Burning Grounds w S s S S SS,a ' *TMeiss s Aiirair.s Ba.ra.sra Celebrating 2S Y ean o f E nvironm ental Progress CFQ32529 EID481626 5 analytical results for "excavated soil" and "Burning Ground Trench" soil. The Report, page 22, states that (p)ost-excavation soil sample analytical results . . demonstrate that the post excavation levels of contaminants were significantly lower, however, DuPont's March 16, 1990 lettet states that all of the hazardous waste encountered was not excavated. Therefore, soil contaminated to the "excavated soil" level are remaining at the Burning Ground and soil is a medium of concern for the RFI. SUBMITTALS Submittal of the RFI Work Plan According to permit condition II.D.l., within 90 calendar days of receipt of this letter or August 11, 1997, whichever is later, submit to EPA and the West Virginia Department of Environmental protection a work plan for the RCRA Facility Investigation for the Local Landfill, Riverbank Landfill including the Anaerobic Digestion Ponds and Burning Grounds, and the Polyacetal Waste Incinerator SPA'S portion of the RCRA permit for correctly action contains, in permit condition IIJD., provisions (or requirements) for the RFI. As a supplement to the permit language, enclosed is a copy of EPA's current permit RFI requirements. Of particular importance are attachment conditions D.2.f and g regarding screening risk assessment and base-line risk assessment. Within 30 days of receipt of this letter, for by June 11, X997, -whichever is later, submit to EPA and WVDEP information identified above or in the enclosed table. Within 60 days of receipt of this letter, or by July 11, 1997, whichever is later, submit to EPA and WVDEP a report on the pumpand-treat system as identified above. It is strongly suggested that prior to submitting the RFI Work Plan, that DuPont meets with EPA in the Regional office. Please call me at 21S-566-3429 to set up a meeting. . enei. ce: G.S. Atwal, WVDEP Remedial Project Manager RCRA Operations Branch Celebrating 25 Years o f E nvironm ental Progress CF032530 EID481627