DuPont Corporate Remediation Group Chestnut Run Plaza 715-240 974 Centre Road P.O. Box2915 Wilmington, DE 19805
November 6, 2012 

# NOV 0 72012

Dr. Maria Doa Director, Chemical Control Division (7405M) Room 4146 EPAEast U.S_ Environmental Protection Agency 1201 Constitution Avenue, NW Washington, DC 20004 202-564-4760 Document Control Office Office ofPollutionPrevention and Toxics EPA East, Room 6428 U.S. Environmental Protection Agency 1201 Constitution Avenue, NW Washington, DC 20004 202-564-8930

Attn: EPA Docket ID Number OPPT-2004-0113 Memorandum ofUnderstanding (MOU) between the U.S. Environmental Protection Agency (EPA) and E. L DuPont de Nemours and Company (DuPont) for a Perfluorooctanoic Acid (PFOA) Site-RelatedEnvironmental Assessment Program (November 3, 2005)

Re: MOUPhase III- Future Work Plan DataAssessmentReport, DuPont Washington Works, Washington. West Virginia, PFOA Site-relatedEnvironmentalAssessment Program (OPPT-2004-0113) and RevisedFinalAmendedScreening LevelExposure Assessment for DuPont Washington Works Facility, Washington, West Virginia, PFOA Site-relatedEnvironmentalAssessmentProgram (OPPT-2004-0113) (November 6, 2012)

DearDr. Doa:

TheMOUPhase III- Future Work Plan DataAssessmentReport, DuPont Washington Works, Washington. West Virginia, PFOA Site-relatedEnvironmentalAssessmentProgram (OPPT2004-0113) (Phase III Data Assessment Report) is submitted in accordance with Section V.F.2 of the above-identified MOU. This report summarizes the multi-media sampling described in the Future Work Plan- Phase III (November 18, 2010). The report presents the results and a discussion ofthese results from Phase III. As with previous status reports, this report includes West Virginia National PollutantDischarge Elimination System (NPDES) and granular activated carbon (GAC) treatment monitoring data that were received as ofOctober 19, 2012. These results were not generated as part ofthe Phase III MOU monitoring activities, but are provided by DuPont for completeness ofstudy. In addition, included with this Phase III Data Assessment Report, is the RevisedFinalAmendedScreening LevelExposureAssessment forDuPont Washington Works Facility, Washington, West Virginia, PFOA Site-relatedEnvironmental AssessmentProgram (OPPT-2004-0113) (RFA SLEA). While this Phase III DataAssessment Report and the RFA SLEA are standalone documents, these deliverables should be reviewed sequentially to obtain a complete understanding ofthe data collected during Phase III, and how these data were used to evaluate human exposures in the RFA SLEA.

The Phase III DataAssessment Report includes a discussion ofdata quality, trends and key findings. Thereport states that all data generated during Phase III reported by the laboratories have beenjudged, via internal and third party data review, as usable for the purposes ofPhase III

E.I. du Pont de Nemours and Company 

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and related projects. Overall, the media-specific concentrations ofPFOA show significant decreases in the past decade due to majorreductions in site emissions. For soil sampled during Phase III and during previous investigations underPhase I and Phase II, concentrations ofPFOA have decreased overtime, and PFOA concentrations are lower with increasing distance from the site. For Ohio River water, Phase III concentrations are over an order ofmagnitude lower than historic concentrations downgradient ofthe Site, and are approximately equal to or less than historic concentrations upgradient ofand adjacent to the Site.

The 2008 SLEA identified several pathways ofpotential exposure, specifically ingestion ofbeef and homegrown produce, where a lack ofdata resulted in uncertainty in that assessment. With the collection ofthe Phase III data, which included information on PFOA content in beeftissue and homegrown vegetables, this uncertainty has been significantly reduced in the 2012 RFA SLEA. In addition, the Phase III data have demonstrated non-detectable to very limited detections ofPFOA in these food stuffs. Ofthe 103 homegrown produce samples that were collected, only two samples showed detectable levels ofPFOA. The Phase III data also show that, while soil and water used for growing produce contained varying levels ofPFOA, the produce grown in that soil and water largely did not contain PFOA above analytical detection limits. Moreover, analysis ofbeeftissue indicated an absence ofPFOA above the analytical detection limit. This latter finding is consistent with data from the peer reviewed literature indicating a relatively short half-life for PFOA in cattle, as well as with USEPA's own work showing no detectable PFOA levels in tissue ofcattle raised on PFOA-contaminated land. The Phase III data also show that, while hay and water sources used for locally-raised cattle contained varying levels ofPFOA, the beeftissue from the locally-raised cattle did not contain PFOA above analytical detection limits.

Since 2000, DuPont has reduced combined air and water emissions from the Site by more than 99%. These reduction and control technologies, along with other exposure mitigation measures, such as installation ofgranular activated carbon (GAC) systems on multiple municipal drinking water systems serving roughly 20,000 residents, and the installation ofGAC filters on the private drinking water supplies ofover 50 homes, have produced significantreductions in potential exposure to PFOA in the area surrounding the Site. Forexample, for the most conservative residential scenario in the "Washington Works exposure area," total intakes calculated in the RFA SLEA are approximately 15- to 50-fold lower than corresponding intakes calculated in the 2008 SLEA. The presence ofPFOA and potential for exposure are expected to decline even further, as DuPont meets its commitment to no longer make, buy or use PFOA by 2015, orearlier if possible.

The reduced exposures calculated in the RFA SLEA are further substantiatedby recent biomonitoring data from the surrounding community. A December 5, 2011, C8 Science Panel Status Report showed that PFOA in blood levels ofpersons living in the vicinity ofthe Site have decreased from a geometric mean level of74.8 ng/mL in 2005-2006 to 30.8 ng/mL in 2010- a reduction ofnearly 60%. Considering the half-life ofPFOA in humans, such a finding is consistent with the significant reductions in potential PFOA exposure in the study area predicted in the RFA SLEA.

With the completion and submission ofthe enclosed two reports, the current PFOA environmental releases and sources ofthose releases from the Site and the presence ofPFOA in the environmental media on and around the Site are sufficiently understood and the pathways of migration and exposure to PFOA associated with the Site have been adequately characterized and assessed on a screening level basis. In so doing, DuPont has fully addressed the Charge presented in the MOU.

Page 2 of3 OPPT-2004-01 13 PFOA Site-Related Environmental Assessment ProgramDocket No. OPPT-2004-0113 EPA-DuPontMOU November 6, 2012

Ifyou need any additional information orfurther clarification, please contact me (302.999.6I97)

or Jenny Liu (302.999.3628).

Very truly yours,

# ~;B/~ Andrew S. Hartten Principal Remediation Project Manager

Enclosures:

Page 3 of3 I paper copy and l digital copy ofthe MOUPhase III- Future Work Plan Data AssessmentReport, DuPont Washington Works, Washington. West Virginia, PFOA Site-relatedEnvironmentalAssessmentProgram (OPPT-2004-0113) and RevisedFinalAmendedScreening LevelExposureAssessment forDuPont Washington Works Facility, Washington, West Virginia, PFOA Site-related EnvironmentalAssessmentProgram (OPPT-2004-0113) (November 6, 2012) I digital copy ofthe MOU Phase III- Future Work Plan Data Assessment Report (November 6, 2012)

OPPT-2004-0113 PFOA Site-Related Environmental Assessment Program

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