DuPont Corporate Remediation Group 

Chestnut Run Plaza 715-240 

974 Centre Road 

P.O. Box2915 

Wilmington, DE 19805 

November 6, 2012 NOV 0 7 2012 

Dr. Maria Doa 

Director, Chemical Control Division (7405M) 

Room 4146 EPA East 

U.S_ Environmental Protection Agency 

1201 Constitution Avenue, NW 

Washington, DC 20004 

202-564-4760 

Document Control Office 

Office of Pollution Prevention 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 of Understanding (MOU) between the U.S. Environmental Protection 

Agency (EPA) and E. L DuPont de Nemours and Company (DuPont) for a 

Perfluorooctanoic Acid (PFOA) Site-Related Environmental Assessment Program 

(November 3, 2005) 

Re: MOU Phase III- Future Work Plan Data Assessment Report, DuPont Washington 

Works, Washington. West Virginia, PFOA Site-related Environmental Assessment 

Program (OPPT-2004-0113) and Revised Final Amended Screening Level Exposure 

Assessment for DuPont Washington Works Facility, Washington, West Virginia, PFOA 

Site-related Environmental Assessment Program (OPPT-2004-0113) 

(November 6, 2012) 

Dear Dr. Doa: 

The MOU Phase III- Future Work Plan Data Assessment Report, DuPont Washington Works, 

Washington. West Virginia, PFOA Site-related Environmental Assessment Program (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 of these results from Phase III. As with previous status reports, this report includes 

West Virginia National Pollutant Discharge Elimination System (NPDES) and granular activated 

carbon (GAC) treatment monitoring data that were received as of October 19, 2012. These 

results were not generated as part of the Phase III MOU monitoring activities, but are provided by 

DuPont for completeness of study. In addition, included with this Phase III Data Assessment 

Report, is the Revised Final Amended Screening Level Exposure Assessment for DuPont 

Washington Works Facility, Washington, West Virginia, PFOA Site-related Environmental 

Assessment Program (OPPT-2004-0113) (RFA SLEA). While this Phase III Data Assessment 

Report and the RFA SLEA are standalone documents, these deliverables should be reviewed 

sequentially to obtain a complete understanding of the data collected during Phase III, and how 

these data were used to evaluate human exposures in the RFA SLEA. 

The Phase III Data Assessment Report includes a discussion of data quality, trends and key 

findings. The report states that all data generated during Phase III reported by the laboratories 

have been judged, via internal and third party data review, as usable for the purposes of Phase III 

E. I. du Pont de Nemours and Company CONTAINS NO CB 
Docket No. OPPT-2004-0113 

EPA-DuPont MOU 

November 6, 2012 

and related projects. Overall, the media-specific concentrations of PFOA show significant 

decreases in the past decade due to major reductions in site emissions. For soil sampled during 

Phase III and during previous investigations under Phase I and Phase II, concentrations of PFOA 

have decreased over time, and PFOA concentrations are lower with increasing distance from the 

site. For Ohio River water, Phase III concentrations are over an order of magnitude lower than 

historic concentrations downgradient of the Site, and are approximately equal to or less than 

historic concentrations upgradient of and adjacent to the Site. 

The 2008 SLEA identified several pathways of potential exposure, specifically ingestion of beef 

and homegrown produce, where a lack of data resulted in uncertainty in that assessment. With 

the collection of the Phase III data, which included information on PFOA content in beef tissue 

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 of PFOA in these food stuffs. Of the 103 homegrown produce samples that were 

collected, only two samples showed detectable levels of PFOA. The Phase III data also show that, 

while soil and water used for growing produce contained varying levels of PFOA, the produce 

grown in that soil and water largely did not contain PFOA above analytical detection limits. 

Moreover, analysis of beef tissue indicated an absence of PFOA 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 of cattle 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 

of PFOA, the beef tissue 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 of granular activated carbon (GAC) systems on multiple municipal drinking 

water systems serving roughly 20,000 residents, and the installation of GAC filters on the private 

drinking water supplies of over 50 homes, have produced significant reductions in potential 

exposure to PFOA in the area surrounding the Site. For example, 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 of PFOA 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, or earlier if 

possible. 

The reduced exposures calculated in the RFA SLEA are further substantiated by recent 

biomonitoring data from the surrounding community. A December 5, 2011, C8 Science Panel 

Status Report showed that PFOA in blood levels of persons living in the vicinity of the Site have 

decreased from a geometric mean level of 74.8 ng/mL in 2005-2006 to 30.8 ng/mL in 2010- a 

reduction of nearly 60%. Considering the half-life of PFOA in humans, such a finding is 

consistent with the significant reductions in potential PFOA exposure in the study area predicted 

in the RF A SLEA. 

With the completion and submission of the enclosed two reports, the current PFOA 

environmental releases and sources of those releases from the Site and the presence of PFOA 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 Program 
Docket No. OPPT-2004-0113 

EPA-DuPont MOU 

November 6, 2012 

If you need any additional information or further 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 of the MOU Phase III- Future Work Plan Data 

Assessment Report, DuPont Washington Works, Washington. West Virginia, 

PFOA Site-related Environmental Assessment Program ( OPPT-2004-0113) and 

Revised Final Amended Screening Level Exposure Assessment for DuPont 

Washington Works Facility, Washington, West Virginia, PFOA Site-related 

Environmental Assessment Program (OPPT-2004-0113) (November 6, 2012) 

I digital copy of the MOU Phase III- Future Work Plan Data Assessment Report 

(November 6, 2012) 

OPPT-2004-0113 PFOA Site-Related Environmental Assessment Program 
CONTAINS NO CBI