P. 1 

lrJ"32-u F177 

Civil 

Mitchell J. Small 

H. John Heinz III Professor 

of Environmental Engineering 

Camegie Mellon University 

Porter Hall 129, Frew Street 

Pittsburgh, Pennsylvania 15213 

(412) 268-8782 

Fax: (412) 268-7813 

ms35@andrew.cmu .edu 

July 17, 2009 

Director, Chemical Control Division (7045M) 

Room 4146 EPA East 

US Environmental Protection Agency 

1201 Constitution Avenue, NW 

Washington, DC 20004 

202-564-4760 

Attn : EPA Docket ID Number OPPT-2004-0113 (Lawrence Carter) 

Memorandum of Understanding (MOU) between the US EPA and E.I . DuPont de 

Nemours and Company (DuPont) for a Perfluorooctanoic Acid (PFOA) Site-Related 

Environmental Assessment Program : Final Report of ITP-convened PCP process. 

Dear Sir/Madam: 

With this letter I wish to submit to the EPA the final report of the Carnegie Mellon -

Independent Third Party (ITP) Peer Consultation Panel (PCP) process convened to evaluateand comment upon reports and supporting studies implemented by E. I. DuPont de Nemour5,_ 

and Company (DuPont) and their consultants for their Perfluorooctanoic Acid (PFOA) Site= 

Related Environmental Assessment Program, Phase 11 studies. The report is also available to 

the public on the CMU ITP website found at: 

http ://itp-pfoa .ce.cmu.edu 

Both the report and the website provide documentation of the review process that has occurred 

over the past 1'/2 years. 

We would like to thank scientists and other staff members at DuPont and EPA who cooperated 

fully with us in providing the information and support necessary to complete this report . We 

hope that it provides useful guidance for future data collection and studies at the DuPont 

Washington Works manufacturing plant and nearby locations. 

CONTAINS NO CPI 
Please contact me if you have any questions at this time. 

Sincerely yours, 

Mitchell J . S4na11 

Independent Third Party Administrator 

H. John Heinz III Professor of Environmental Engineering 

Civil & Environmental Engineering and Engineering & Public Policy 

cc: Andrew S . Hartten, DuPont Project Director 

Cathy Fehrenbacher, Chief, Exposure Assessment Branch, US EPA 

Members of the Peer Consultation Panel 

( C.F~~ 
Final Report 

of the 

Peer Consultation Panel 

conducting the review for the 

Scientific Peer Consultation Process for a Site Environmental Assessment Program 

as part of the 

DuPont - EPA Memorandum of Understanding and Phase lI Workplan 

Edited by 

Mitchell J. Small 

Civil & Environmental Engineering and Engineering & Public Policy 

Carnegie Mellon University 

Pittsburgh, PA 15213 

Independent Third Party (ITP) Administrator 

July 15, 2009 
Members of Peer Consultation Panel 

Mitchell J. Small, Ph.D., 

Independent Third Party Administrator 

Carnegie Mellon University 

Joel Baker, Ph.D. 

University of Washington Tacoma 

Kannan Kurunthachalam, Ph.D. 

Wadsworth Center, New York State Department of Health 

State University of New York at Albany 

Linda S. Lee, Ph.D. 

Purdue University 

Paul J. Lioy, Ph.D. 

UMDNJ - Robert Wood Johnson Medical School 

Scott A. Mabury, Ph.D. 

University of Toronto 

Michael McLachlan, Ph.D. 

Stockholm University 

Rosalind A. Schoof, Ph.D., DABT 

Integral Consulting Inc. 

Thomas B. Watson, Ph.D. 

Brookhaven National Laboratory 

Technical and administrative assistance for the peer consultation was provided by 

Kan Shao and Gloria Dadowski of Carnegie Mellon University. 
Table of Contents 

1 . Introduction and Overview . . .. . . .. . . .. . . . .. . . .. . . .. . . . .. . ... . ... . . .. . . ... . ... . . .. . . ... . ... . . ... . . .. . . .. . . . .. . . . .. . . ... . . ... . . . . . .4 

1 .1 Review Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

2. Summary of Key Findings and Conclusions . .. . . .. . . .. . . . .. . ... . ... . . . .. . ... . . .. . . . .. . . . . . . . . . . . ... . . ... . . .. . . . .. . . . . . .7 

2.1 For the Air Monitoring and Dispersion Modeling Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

2.2 For the Surface Water and Sediment Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

2.3 For the Soil and Groundwater Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

2.4 For the Assessment of PFOA in Biota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

2.5 Assessment of Multimedia Fate, Transport, and Exposure Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

2.6 Assessment of Human Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i 1 

2.7 Summary of Priority Needs for Future Monitoring and Model Development . . . . . . . . . . . . . . . . . . . . . 13 

3. Detailed Findings. . . . .. . . . .. . . .. . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . .. . . ... . . ... . . .. . . . ... . .... . .15 

3 .1 Air Monitoring and Dispersion Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 

3 .1 .1 Identification and Characterization of Transport Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

3 .1 .2 Source Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 

3 .1 .3 Air Monitoring Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 

3 .1 .4 Air Modeling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 

3 .1 .5 Data Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

3 .2 Surface water and Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

3 .2 .1 Ohio River. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 

3 .2 .2 Washington Works Outfall Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 

3 .2 .3 Landfill Surface and Leachate Analysis for Local, Dry Run, and Letart . . . . . . . . . . . . . . . . . . . . . . 26 

3 .2 .4 Other Surface Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 

3 .2 .5 Washington Works Site Potential for Additional PFOA Transport to Ohio River . . . . . . . 27 

3 .2 .6 Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 

3.2.7 Analytical Comment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 

3.1 .8 Specific Data Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 

3 .3 Soil and Groundwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 

3.3 .1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

3.3 .2 Washington Works Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 

3.3 .3 LHWA Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 
3 .3 .4 Local, Dry Run, and Letart Landfills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 

3 .3 .5 Comment on Ranking of Exposure Pathways Related to Groundwater for SLEA. . . . . . . 37 

3.3 .6 Specific Data Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 

3 .4 Biota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

3.4.1 Farm Produce and Local Population/Farmers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

3 .4 .2 Fish and Anglers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 

3 .4 .3 Breast Milk and Infants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 

3 .4 .4 Game Animals and Hunters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

3 .4 .5 Summary of Key Concerns Regarding Biota Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 

3.5 Multimedia Fate, Transport, and Exposure Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 

3.5 .1 Pathways of Exposure from the Site to Exposure Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

3.5 .2 Understanding of the Processes Governing PFOA Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 

3.5 .3 Quantification of PFOA Mass Flows Along the Major Pathways of Migration . . . . . . . . . . . 48 

3 .5 .4 Site-specific Empirical Evidence to Support the Semi-quantitative Understanding of 

the Major Pathways of Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 

3 .6 Human Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 

3 .6 .1 Conceptual Exposure Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 

3 .6 .2 General Exposure Assessment Methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

3 .6 .3 Interpretation of Significant Exposures in Light of Potential Health Risks . . . . . . . . . . . . . . . . . . 53 

3.6 .4 Exposure Point Concentration Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 

3.6 .5 Specific Exposure Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 

3.6.6 Uncertainty Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 

3.6.7 Conclusions and Identification of Data Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 

3 .7 Summary of Priority Data Needs for Future Study Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . `8 

3.7.1 Comprehensive Air Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 

3 .7 .2 Spatially Extensive Surface Water Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

3 .7 .3 Intensive River Sediment Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

3 .7 .4 Groundwater Pump and Tracer Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

3 .7 .5 Additional Biological Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 

3 .7 .6 Implementation of Multimedia Model to Evaluate Mass Balance in Nearby 

Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 

References . . . . . . ... . . ... . . . . . . . .. . . .. . . . .. . . ... . . ... . ... . . .. . . . .. . . .. . . .. . . ... . . .. . ... . . ... . ... . ... . . . .. . . .. . . .. . . . .. . . . .. . . .. . . .... . . ., . . . ... . 62 

Appendix A . . . . . .. . . . .. . . . .. . . ... . . .. . . . .. . . .. . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . .. . . .. . . . .. . . .. . . . . . . . .. . . . . . . . . . . . ... . . ... . . .. . . . .. . . . . . . . ... . 63 

A.1 Summary of March 23-24, 2009 Pubiic Meeting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63 

A.2 Public Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 
1 . Introduction and Overview 

This report summarizes the findings of the Peer Consultation Panel (PCP) convened to review the 

site environmental assessment program conducted by E.I . DuPont de Nemours and Company 

(DuPont) under a Memorandum of Understanding (MOU) with the United States Environmental 

Protection Agency (EPA), Office of Pollution Prevention and Toxics (OPPT). DuPont and EPA 

are signatories to the MOU in which DuPont has committed to provide EPA with certain data and 

information on perfluorooctanoic acid and its salts (PFOA) through a PFOA Site Related 

Environmental Assessment Program. In particular, the studies conducted by DuPont address the 

fate of PFOA at and near the DuPont Washington Works manufacturing plant located along the 

Ohio River, just west of Parkersburg, West Virginia. 

The peer review is evaluating the scientific quality and completeness of ongoing studies 

conducted by DuPont and its scientific consultants to characterize past and current releases 

associated with the site, as well as quantities of PFOA in nearby environmental media, including 

those media that can lead to human exposure. This data gathering has been conducted through 

the implementation of phased activities, known as Phase I and Phase II, and set in a Phase II 

Work Plan. Under the MOU, DuPont used the Phase I and Phase 11 data along with other relevant 

information to prepare the following reports : 

A. Data Assessment: DuPont Washington Works (OPPT-2004-0113 PFOA Site-Related 

Environmental Assessment Program), DuPont Corporate Remediation Group, Project 

No. : 507532/507533 18984356.05013, October 2, 2008. 

B. Screening Level Exposure Assessment for DuPont Washington Works Facility, 

Parkersburg, West Virginia (OPPT-2004-0113 PFOA Site-Related Environmental 

Assessment Program), Environ, October 2, 2008 . 

C. Future Data Needs Assessment: DuPont Washington Works (OPPT-2004-011 "s PFOA 

Site-Related Environmental Assessment Program), DuPont Corporate Remediation 

Group, Project No . : 507532/507533 18984356.05013, October 2, 2008. 
The specific goal of the PCP is to evaluate these reports (and related supporting informati:m 

provided by DuPont and its consultants) to determine whether an affirmative answer can be 

provided to the charge question posed in the DuPont-EPA MOU: 

Are current PFOA environmental releases and sources of those environmental releases 

from the Site and the presence of PFOA in environmental media on and around the S'.te 

sufficiently understood so that pathways of migration and exposure to PFOA associated 

with that Site are adequately characterized and assessed on a screening level basis? 

1.1 Review Process 

The members of the Peer Consultation Panel (PCP) were selected by ITP Administrator Mitchell 

Small following a public nomination procedure announced on the Carnegie Mellon PFOA Peer 

Consultation website: lltti) ://itp-pi<~a .ce .cmu.edu/. The nomination procedure, described at 

htt.p ://itp-pfoa .ce.cniu.edu/tna ,es/pecr .html was closed on August 22, 2008. A total of 13 

candidates were nominated by the US EPA (6), DuPont (3), Mitchell Small (3), Robert L. Griffin 

(1), and self nomination (1) . Members were chosen based on the need to address particular areas 

of expertise in the study and the strength of each individual's scientific qualifications . The final 

committee includes four members nominated by the US EPA, two members nominated by 

DuPont, two members nominated by Mitchell Small, and one member nominated by Robert L. 

Griffin (a member also nominated by the US EPA). 

The committee received copies of the three DuPont reports on November 3, 2008, and held a first 

organizational teleconference on November 18, 2008 . The first formal meeting of the PCP took 

place with a publicly announced teleconference on December 23, 2008. Input to the panel on the 

charge and related information was provided by the representatives of the US EPA and DuPont. 

There it was decided that the panel would subdivide the review and preliminary writing tasks 

with major and minor assignments as follows: 
Table 1 . PCP Focus Areas and Panelist Assignments 

Surface 

Air water & Soil & 

Biota Multi- Human 

Panel Member 

sediment groundwater Media Exposure 

Joel Baker Minor Major 

Kannan 

Kurunthachalam Minor Major 

Linda S. Lee Major Minor 

Paul J . Lioy Minor Major 

Scott A. Mabury Minor Major Minor 

Michael 

Mclachlan Minor Major 

Rosalind A. 

Schoof Minor Major 

Thomas B . 

Watson Major Minor 

The committee conducted further public teleconference meetings on February 23 and March 11, 

2009, to discuss their preliminary findings . Following the March meeting, a Final Preliminary 

Report of the PCP was concluded, serving as the basis for discussion at the public face-to-face 

meeting of the PCP that was held on March 23-24, 2009, in Parkersburg, West Virginia . The 

Parkersburg meeting included presentations by the US EPA and DuPont, further discussion of the 

Preliminary Report by the PCP, and public input. A summary of the Parkersburg meeting is 

included as Appendix A, including public comments submitted to the PCP during or closely 

following the meeting (Appendix A.2) . Full audio-video documentation of the meeting is found 

at : 

littU :i/itt.~-ploa .ce.cniu .c(Iu ;pa,_~c5-'annoiiaiccmetutshtml . 

Further revisions to the Preliminary Report were made following the Parkersburg meeting and 

discussed at a subsequent public teleconference held on May 19, 2009, leading to a draft final 

report. The draft final report was posted for public comment on June 4, 2009. One set of 

comments was received on this report ; these are presented in Appendix A.2 . The PCP undertook 

minor edits of the final report to address the public comments, and the final report was completed 

for submission to the US EPA on July 16, 2009. This final report was also posted on the public 

web site for the Peer Consultation project on that day. 
2. Summary of Key Findings and Conclusions 

The PCP finds that the three reports reviewed provide a good first conceptualization and analysis 

of potential pathways of PFOA exposure at and near the Washington Works Site. Furthermore, 

much of the data that has been collected and analyzed will be useful in estimating the likely 

magnitude of these exposure pathways and their relative importance on a screening level basis. 

However, the panel has also found significant limitations and omissions in the datasets and 

associated modeling for estimating the relative and absolute importance of different exposure 

pathways, and recommends that a significantly expanded set of data collection and analyses 

should be conducted to fill critical gaps. 

It should be noted that members of the panel did differ in their understanding and expectations of 

what was meant in the charge by, "adequately characterized and assessed on a screening level 

basis." Some members interpreted this to mean that the migration and exposure assessment 

should be at the current state-of-the-art in the scientific literature and practice for such 

assessments, with full coverage of potential migration and exposure pathways. Others interpreted 

the term "screening" to imply that a somewhat mare initial assessment was intended, which 

would then encompass a more-limited sampling and evaluation of a more-limited set of pathways. 

This difference in interpretation is reflected in differences between some of the comments made 

by different panel members and presented in our findings below. 

Key findings include : 

2.1 For the Air Monitoring and Dispersion Modeling Assessment: 

2 .1 .1 The conclusion that air emission, transport, and deposition is the primary pathway 

to contamination of drinking water is plausible, but is not adequately substantiated by the 

data and analyses that are presented in the reports . 

2 .1 .2 The selection of a two-mile radius around the plant seems insufficient to 

characterize the spatial extent of impact and potential exposures to PFOA released from 

the Site. The selection of this domain must be justified or the domain should be 

expanded and a more detailed characterization of the entire domain is needed. 
2 .1 .3 The temporal resolution of the air monitoring was insufficient to characterize the 

transport and dispersion of PFOA in the areas likely to be affected by emissions . 

2.1 .4 The data set used to evaluate the dispersion modeling is inadequate. 

2.1 .5 There was no attempt to evaluate the air monitoring and modeling by accounting 

for the released material . There should be an attempt made to perform a mass balance 

calculation for airborne material. 

2.1 .6 There is evidence that all airborne sources of PFOA have not been identified. Air 

monitoring should be performed at the landfill sites to eliminate them as possible sources 

of airborne PFOA as well as at the facility now known as the Little Hocking Service 

Center, especially if incineration occurs at this site . 

2.2 For the Surface Water and Sediment Assessment: 

2 .2 .1 Ohio River water sampling was very intermittent, and lacking in information 

regarding time of day or week, plant operation, river flow etc. As such, it is difficult to 

interpret what the reported river water concentrations mean. 

2 .2 .2 Adequate explanation is not provided for the absence of detectable PFOA in river 

samples along transects near the site, given the presence of PFOA in Ohio River and 

drinking water intake samples many miles downstream. 

2 .2 .3 Water samples at the Washington Works outfalls and landfill leachate and surface 

water samples suggest that these locations could have provided potentially important 

routes of PFOA transport to groundwater and the Ottio River. More extensive sampling 

associated with the landfills is needed. 

2.2 .4 No water samples were collected at other surface water bodies, neither in the study 

area nor in any stream or river sediments . PFOA in these media could lead to exposure to 

biota and subsequently through the human food chain. 
2 .3 For the Soil and Groundwater Assessment : 

2.3 .1 Substantial soil and groundwater data have been collected and the general routes of 

exposure have been defined. However, the groundwater flow model has not been 

adequately validated for use in the assessment. 

2 .3 .2 PFOA air emissions clearly were and still are a large contributor to contamination 

of drinking water via the air-soil-groundwater route especially within a few mile rac'.ius of 

the site . However, significant contributions !o drinking water contamination from 

additional PFOA transport modes cannot be ruled out . 

2.3 .3 Collection of additional samples associated with potential contamination of 

groundwater and migration to off-site streams from the ponds and contaminated layers in 

or near the water-bearing zones under the former (closed and capped) landfills are 

warranted as well as some post monitoring of the Riverbank Landfill and Anaerobic 

Digestion ponds that will have an engineered cap system. 

2.3 .4 Additional assessment as to whether or not pumping at LHWA induces any 

unexpected hydraulic connection between the groundwater associated with the Anaerobic 

Digestion ponds is suggested as well, given the high PFOA concentrations observed in 

the wells immediately north of the ADP even after pond material was removed. 

2.3 .5 Clarification regarding the potential off-site transport scenarios that may occur if 

pumping at the Ranney Well, the DuPont-Lubeck Well Field, or the East Well Field were 

to cease for some period of time is needed. 

2 .4 For the Assessment of PFOA in Biota: 

2.4.1 Biota can be an important pathway of PFOA exposure to the local populations . 

There is a need to determine concentrations of PFOA in several biological matrixes to 

accurately assess exposures. There are data gaps in characterizing PFOA in biological 

media, which can play an important role in the assessment of the migration of PFOA an 

and around the Site and subsequent human exposure. 
2.4.2 Home-grown produce and domestically produced milk have been identified in the 

Future Data Needs Assessment report as priorities for future data collection. In addition, 

it is recommended that PFOA data for farm produce, locally produced meat, fish from 

surface waters, breast milk samples and game animals (game hen) be collected to account 

for potential biological matrixes that could contribute to exposures . 

2.4 .3 Several aspects of the SLEA, as described in the reports, require further, moreadequate justifications . For example, exposure assessment of PFOA from the ingestion 

of local fish by anglers involved several non-conservative assumptions on fish species, 

ingestion rates, exposure duration and concentrations in fish. These estimates have 

introduced uncertainties that could potentially lead to an underestimate of actual 

exposures by 1 to 2-orders of magnitude. There is a need to refine the exposure models 

for fish consumption . 

2 .4 .4 Other biological media such as breast milk and game animals should be identified 

as potential exposure pathways to PFOA for certain subpopulations . Justifications are 

required to explain why these pathways are not considered in the current report and/or 

these pathways should be identified in the `Future Data Needs Report" for future study. 

2.5 Assessment of Multimedia Fate, Transport, and Exposure Pathways: 

2.5 .1 The site conceptual model adequately describes many of the transport pathways to 

people living close to the source. However, neither the exposure to PFOA nor the 

pathways of migration for people living more distance from the plant are characterized . 

This deficit is judged to be particularly serious for the population exposed via river water 

downstream of the site . 

2.5 .2 The site conceptual model appears to be factually incorrect in its placement of the 

SWMU and its correct location, on the rim of the river. The conceptual model also omits 

a potential transport pathway from the SWMU into the Ohio River and a pathway into 

groundwater that may also flow away from the Site. 

2 .5 .3 Migration within media (air and water) has been addressed elsewhere in this p---,r 

consultation . There appears to be a basic understanding of some intermedia transport 

10 
processes (e.g . river water to ground water). However, several intermedia pathways of 

migration of PFOA are not yet understood at a basic level . Deficits exist particularly 

regarding the transport of PFOA from surface soil to groundwater, and from air and water 

to food. 

2 .5 .4 A semi-quantitative description of the mass flows along some partial pathways of 

migration is presented (e.g. from air to surface soil) . However, no assessment along the 

entire major pathways (e.g. air - surface soil - groundwater - drinking water) is 

provided. 

2 .5 .5 Da' ta were collected and assessed to evaluate the atmospheric transport and 

deposition to soil following emissions to air at the Washington Works site. Data were 

also coilected in surface water, but no effort was made to assess the relationship between 

emissions to surface water and transport via surface water. Measurements were 

conducted that supported the understanding of the relationship between atmospheric 

emissions and deposition to terrestrial surfaces, but no effort was identified that evaluated 

quantitative understanding of the link between atmospheric emissions and the levels in 

groundwater in the unsaturated or saturated zones. Measurements to assess the transfer of 

PFOA from air and water to food are fully absent. 

2.6 Assessment of Human Exposure: 

2 .6 .1 The SLEA does not make sufficient effort to obtain and use local exposure 

concentrations, and exposure factors and behaviors for the local population, or to provide 

sufficient justification for the values used when local data or exposure parameters are not 

available . The authors used information from EPA guidance documents during the 

completion of their analyses, and applied general exposure factors to replace missing or 

unavailable information and data without adequate discussion of their reasoning for 

relying on these values. 

2.6 .2 While estimates for drinking water exposure are based upon site data, little or no 

data are available for the other exposure pathways (e.g . air, soil ingestion, food etc .) . All 

calculations are based upon hypothetical individuals represe .iting a reasonable maximum 

exposure (RME) or mean typical exposure (MTE) to represent high end and central 

11 
tendency levels of exposure, respectively . While this approach is reasonable, many of the 

activities and the frequency of activities used to estimate exposure to these hypothetical 

individuals were speculative. At the present time, there is no information provided in the 

document that assists in providing a validation for the baseline assumption used for each 

"receptor" person or population. 

2.6.3 The SLEA does not explain how the resulting intake estimates will be used in 

assessing risks. The lack of information regarding how the exposure estimates will be 

applied may lead to incorrect conclusions in the SLEA. For example, the conclusion that 

inhalation exposures are low compared with other exposure routes is irrelevant if the lung 

is a target organ and inhalation risk will be assessed separately from ingestion and dermal 

exposure. 

2.6 .4 The levels and types of data collected at the Washington Works Facility and Local 

Landfill, the Dry Run landfill, and the Letart Landfill, are not comparable. Thus, 

evaluations between sites are not possible. As a consequence the lack of data across the 

sites leads to major gaps in the ability to do site-specific screening exposure 

characterizations . 

2.6 .5 The five-year exposure duration used in the SLEA is a departure from standard risk 

assessment approaches and also requires an early explanation in the documynt. 

2 .6 .6 There is a lack of objective analysis of the relative degree of uncertainty for the 

different exposure pathways. 

2.6.7 The reliance on comparison with drinking water exposures as a basis for 

discounting the importance of other exposure patinwz.ys is particularly problematic and 

could be misleading. We understand that the intent is to assess the current drinking water 

status in the next iteration of this document, but this document should not appear to 

discount the relative importance of other exposure pathways based on a comparison with 

drinking untreated groundwater because that comparison does not reflect current 

conditions with widespread water treatment in place, i .e., pathways that seemed minor 

compared to drinking water exposures prior to wzter treatment, may now contribute a 

much greater fraction of total exposures . 

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2.6 .8 The screening exposure assessment should be forward looking in perspective, 

and utilize the extensive biomonitoring data in the population that now receives the 

drinking water through the Little Hocking Water Association, other public systems and 

from private wells. The biomonitoring data should offer insights regarding the current 

variability in exposures . The conceptual model for exposure needs to consider additional 

sampling based upon the recently established emissions from the stacks, and the 

additional data collection efforts described in Section 2.7 . These include air and biota 

monitoring programs that can achieve the goals of a revamped program and the goals of 

an exposure assessment. 

2.7 Summary of Priority Needs for Future Monitoring and Model Development 

As part of our review of the current Data Assessment, Screening Level Exposure 

Assessment, and Future Data Needs Assessment documents, the PCP identified high 

priority areas for further data, collection and model development . These are summarized 

below and may provide useful input in the design of Phase III studies for the Site. The 

recommended measurements include data needed to provide better resolved estimates of 

exposure, as well as for performing a mass balance calculation for historic and current 

PFOA emissions and environmental inventories . 

2.7 .1 A coordinated, ongoing air monitoring program is needed, including time 

coincident measurements of emissions, ambient concentrations, and deposition. 

Monitoring should include direct stack, ambient, and deposition monitoring at time scales 

sufficient to characterize long-term, seasonal, and diurnal variations in PFOA emissions, 

concentrations, deposition, and resuspension. Spatial resolution should be sufficient to 

address vertical variations in concentration that inform flux-deposition processes, and 

horizontal variations across key receptor locations, including the Ohio River, the LHWA 

well field, and more distant locations needed to determine the spatial extent of the Site 

influence. 

2.7.2 A spatially comprehensive synoptic survey of PFOA concentrations in the Ohio 

River is needed to characterize the spatial extent and source-receptor relationships of 

water quality impacts from the Site. If possible, samples should be collected on a single 

13 
day, extending from the Site to downstream areas known to have drinking water 

contamination (e.g ., at least as far as Crab Creek, -90 miles downstream). Samples 

should be obtained in the immediate vicinity of each of the major outfalls to the Ohio 

River and downstream (in line with the river current) and from selected tributary creeks 

and shallow water bodies (e.g ., Brinker Run for Letart Landfill and Lee Creek for Dry 

Run Landfill) that flow through the landfills. PFOA concentrations should be measured 

for co-located water, sediment and fish samples. . 

2.7 .3 An intensive sediment survey is needed for the Ohio River in areas immediately 

adjacent to the Washington Works outfalls, upstream and downstream of the outfalls, and 

downstream of the landfill sites . Transects should be designed to capture the extent of 

PFOA contamination related to a specific outfall and should include differential depth 

analysis. A sediment transect running from the Site across the river to the LHWA should 

also be surveyed to check for the existence of possible seepage zones emanating from the 

Riverbank Landfill (RBL) that could lead to PFOA transport to Ohio River water drawn 

by the LHWA well field . 

2.7 .4 Pump and tracer tests are needed to further explore possible hydraulic connections 

between the Ohio River waters near the Site and groundwaters on both sides of the river. 

The tests should include coincident monitoring of water levels in wells on both sides of 

the river in response to planned or imposed changes in pumping rates at the Ranney Well, 

the DuPont-Lubeck Well Field, the East Well Field, and the LHWA well field. Tracer 

tests should be implemented to test for possible groundwater pathways in or under the 

river bed between the former ADP area and the LWHA well field. In addition, PFOA 

monitoring should be conducted in these areas at existing and new wells along the banks 

of the river. 

2.7 .5 PFOA sampling of biological matrixes representing potential sources of exposure 

to local populations is needed to screen and characterize these pathways, including homegrown produce and domestically produced milk (already identified in the Future Data 

Needs report), farm produce, locally produced meat, breast milk, game animals, and 

possibly additional fish species. These studies should be conducted in conjunction with 

ongoing biomonitoring surveys of the local population to better coordinate exposure and 

biomarker estimates. 

14 
2.7 .6 A multimedia mass balance model should be developed to synthesize the available 

information on PFOA mass flows and environmental inventories . The model should be 

able to track and predict changes in emissions, transport, inventories and exposure over 

time. It should aiso be used to test whether the available information provides a 

consistent and sufficiently certain understanding of PFOA transport and exposure 

pathways from the facility, and to help guide further data collection needs. 

3. Detailed Findings 

3.1 Air Monitoring and Dispersion Modeling 

3 .1 .1 Identification and Characterization of Transport Pathways 

The Screening Level Exposure Assessment (SLEA) report states that 

"The results of this assessment indicate that ingestion of drinking water is the primary 

exposure pathway for potentially exposed populations in the vicinity of the Washington 

Works facility and Local Landfill, Dry Run Landfill, and Letart Landfill" (p. ES-5) 

The possible transport pathways from the Site are identified in the conceptual model (Figure 1 .2) . 

Deposition of airborne PFOA is the primary pathway to contamination of drinking water in the 

conceptual model. Characterization of this pathway is essential for an accurate SLEA. 

3 .1 .2 Source Characterization 

Air emissions from the Site were 29,900 lbs . in 2000 and were reduced to 300 Ibs. in 2006. An 

air emissions inventory was developed for 11 permitted sources at the Site using calculations 

based on a quantity of PFOA emitted per unit of production, a loss factor, and a scrubber 

efficiency factor. There was no direct monitoring of atmospheric emissions during the air 

monitoring studies . There was no monitoring of emissions at landfill sites . 
3 .1 .3 Air Monitoring Program 

Domain 

All air monitoring was conducted within a two-mile radius of the Site even though Figure 5.7 

shows PFOA in residential water supplies at levels above 5.0 p,g/L outside of the 2-mile radius 

(Data Assessment, Figures 5.7 and 5 .2) . 

Sampling 

Air sampling was accomplished by collecting 24-hour integrated samples using two sampling 

methods . The first method used OSHA Versatile Sampling Tubes (OVS) and collected samples 

at approximately one L min- . The second method used high volume samplers (HVS) collecting 

at a rate greater than 1000 L min-' . Limits of detection (LOD) and quantitation (LOQ) for both 

methods were determined using the signal to noise ratio of the analytical method (Data 

Assessment, Appendix 2.2) . In Phase 1 monitoring there was an LOD=40 ngrri 3 and an LOQ=70 

ngxri; for OVS sampling and LOD= 0.4 ngm; and LOQ= 0.7 ngm' for the HVS (Data 

Assessment, Appendix 5 .2) . Phase 2 confidence limits had to be calculated from the footnotes in 

Table 5.2 of the report and are given here in Table 1 . High volume samplers were used with 

cascade impactors to produce particle size distributions . The above ground elevation of the 

intake tubing was 3.6 feet. 

Table 1 : Limits of detection and quantitation for Phase 2 OVS and HVS sampling (data 

from Data Assessment, Table 5.2) 

Sampler Rate Volume Volume analytical Sampling sampling 

(Lmini 1) (L) (m) LOD (ng) LOD (ngnf 3) LOQ (ngm'3) 

0 *1S 1 .00 1,440 1 .44 0 .6 0.42 2.08 

H7#1S 1,000 1 .4E6 1,440 0.6 4.17E-04 2.08E-03 

Fhase 1 monitoring was conducted from November 2003 to March 2004 and consisted of 6 

events measured at 5 locations . Duplicate samples were collected at one location . Air emissions 

during the sampling of this phase were approximately 50001bs . per year (Data Assessment, 

Figure 4.1) . 
Phase 2 monitoring was conducted from August to October 2005 and consisted of 9 events with 

samples collected at 9 locations . Duplicate samples were collected at one location. Because of 

improvements in the analytical method resulting in lower detection limits between Phase 1 and 

Phase 2 monitoring, and because the high-volume samplers were operated at 1000 times higher 

flow rates than the OVS samplers, the data from the Phase 2 HVS samples were considered to be 

"more representative of actual air concentrations" and were used in the model comparison and the 

SLEA. Air emissions during this phase were less than 5001bs. per year (Data Assessment, Figure 

4.1) . 

Results 

There was no vapor phase material detected on the OVS tubes XAD resin in either Phase 1 or 

Phase 2 monitoring. 

The concentration range reported in Phase 1 data from the OVS samplers ranged from non-detect, 

less than the LOD of 40 ngrri ;, to 900 ngm' . Median particle diameter is less than 1 micron, 

with -60% of the particles less than 0.3 microns (Data Assessment, Appendix 5 .1) . 

The Phase 2 data were substantially different from those reported for Phase 1 . This is likely a 

consequence in the significant reduction in emissions from 2003 to 2005, but is not discussed in 

the report . Concentrations seen in HVS samples ranged from 0.01 to 75.9 ngm 3 . Approximately 

60% of the PFOA particles collected during the 9 events were less than 1 .3 pm in diameter (Data 

Assessment Table 5 .5) 

There are significant discrepancies in the Phase 2 monitoring data. 

The maximum concentration seen in Phase 2 was in the samples collected on October 11 and 12 

du:-ing event 8 at location 10/11 . The HVS sample designated 10/11 was collected at the site 

fence line (Data Assessment, Figure 5.2) . Two OVS samples were also collected at this location. 

A comparison of these OVS and HVS samples reveals significant unexplained differences in 

reported results. The HV S samples had concentrations of 73.5 and 75 .9 ngtn' of PFOA. One of 

the two OVS samples had no PFOA above the LOD of 0.4 ngm"; while the other OVS samplhad a concentration of 36.8 ngrn; . The HVS value of 70 ngm; is 35 times the LOQ of the 'JVS 
samplers. The reasons for the differences between the two sampling methods and the two OVS 

samplers are not explained . 

The winds during Phase 2 Event 8 were from the north east at 1 .54 to 3 .09 ms las measured at 

both onsite and offsite meteorological stations (Data Assessment, Appendix 5.2, Figures B-8 and 

B-17). The samplers at locations 10/11 were upwind of the manufacturing site. The reason that 

the maximum concentration was seen when the winds were coming from a direction where there 

was no known PFOA source is not explained . 

Another significant discrepancy is presented in the report 

"Air concentrations tend to decrease with distance from the Site in all directions except in 

the northeast quadrant where there is a slight increase at the 2-mile monitoring station . 

This increase cannot be explained definitively, but may be a result of terrain issues since 

this point is elevated and closer to the plume centerline. . ." 

(Data Assessment, p 42). 

This implies that there is a significant quantity of PFOA above the surface and that there is 

transport and deposition outside the monitored area. Limiting monitoring to 3.6 feet above the 

surface and within a 2 mile radius from the known air emissions sources is unlikely to account for 

all the material released from the site . 

The results from Phase 1 and 2 air monitoring show significantly higher PFOA concentrations 

than measurements reported by the European Food Safety Authority from two studies examining 

PFOA background levels (EFSA, 2008) . Measurements made in the United Kingdom found 

airborne exposures of 0.226 to 0.828 ngm ; in March and 0.006 to 0.222 ngm 3 in November of 

2005. The same report presents results of a study conducted in rural Norway where measured 

PFOA levels ranged from 1 .4 x 10-; to 1 .7 x 10-; ngm 3 . These PFOA levels are an order of 

magnitude lower than the lowest values seen using the HVS sampling method. 
3 .1 .4 Air Modeling 

"It is important to ensure traditional modeling approaches are applicable to perfluorinated 

compounds, which are known to have unusual properties." 

(Data Assessment, Appendix 5.3 p 1 .) 

The performance of two different models, ISCST3-PRIME and AERMOD, were evaluated by 

comparing each model's predictions with the results of the Phase 2 HVS measurements. PFOA 

source data input to the models was generated from an emissions inventory calculated from 

production correlation factors . The dependence of model performance on meteorological input 

was tested using data from two weather stations . One set of data were from an observing system 

at the Washington Works Site within the Ohio River Valley. The other were from an offsite 

meteorological tower located outside of the valley in Little Hocking OH, approximately one mile 

from the facility and at a higher elevation than the on-site station . 

AERMOD predictions were either close to, or over predictions of measured PFOA 

concentrations . Only 15% of the AERMOD predictions were less than the observed values. The 

performance of AERMOD was essentially the same when on-site or off-site meteorological input 

data were used. 

ISCST3-PRIME predictions were less than measured PFOA concentrations approximately half 

the time with either on-site or off-site meteorological input, but exhibited less precision that the 

AERMOD predictions . There was better performance using the off-site meteorological input data 

- the number of close approximations was increased. The under prediction was attributed to 

errors in the model results when the plume centerline is above the mixing height. 

The conclusion of the model evaluation was that AERMOD performed better than ISCST3-

PRIME because it made predictions that were closer to measured vales and erred on the side of 

over prediction. The superior performance of AERMOD is attributed to a better representation in 

the model of turbulent conditions and interactions with complex terrain . The report states that 

"AERMOD provides conservative ambient predictions of PFOA near a manufacturing 

facility that is useful for permitting or assessment purposes." 

(Data Assessment, p. 44) 
There was no effect on predicted PFOA concentrations when deposition was included in the 

AERMOD calculations . 

Evaluation of Air Monitoring and Dispersion Modeling in the Environmental Assessment 

Program 

Examination of the air monitoring and modeling programs and the data they produced raises a 

number of questions about the sources, transport, and fate of PFOA in the area around the site. 

The atmospheric transport pathway is not well understood. The Site-Released Environmental 

Assessment Program (SLEA) is not based on an adequate understanding of the sources and 

transport mechanisms of PFOA in the environment . 

Specific deficiencies in the analysis are : 

1 . The airborne PFOA sources are insufficiently characterized . 

The site emission factors were developed from production correlation factors that apply 

empirically derived formulas to determine emissions from production history. There was no 

attempt made to verify the production factors from direct emissions measurement during either of 

the air monitoring phases . At a minimum, there should be further explanation of the 

measurements that were used to determine these formulas and data on the validation of these 

calculations with actual stack monitoring. Actual stack monitoring during air monitoring would 

be even better . 

There was no air monitoring at the landfill sites . The assumption made in the assessment was that 

the sites had engineered covers that prevented emissions . The fact that the highest levels of 

PFOA seen during Phase 2 occurred when the wind was coming from the northeast, upwind of 

the site suggests that there is a strong local source other than the industrial plant. This source 

should be identified. Air monitoring should be performed at the landfill sites to eliminate them as 

possible sources or airborne PFOA. 

2 . The spatial resolution of the air monitoring was insufficient to characterize the transport and 

dispersion of PFOA in the areas likely to be effected by emissions . 
The sampling domain was limited to 2 miles around the site. Figure 5 .7 shows that there is well 

contamination above 5 pgL;' outside that radius. Figure 5 .2 shows average air concentrations 

over the nine Phase 2 events for all sampling locations . These range from 0.05 to 25 ngrri 3 . 

These values are well above those reported from urban and rural monitoring in Europe (EFSA 

2008). However, the extent of the area impacted by PFOA emissions from the site is not 

established by the air monitoring program. Atmospheric transport and deposition cannot be 

accurately assessed, or the effects of the site delineated, without extending the study domain until 

the measured PFOA concentrations are at or near atmospheric background levels . 

There was no air sample collected at a height greater than 3 .6 meters above the surface . 

Measurements in the vertical dimension are necessary to fully characterize the PFOA transport 

regime and provide data for model verification. 

3. The temporal resolution of the air monitoring was insufficient to characterize the transport and 

dispersion of PFOA in the areas likely to be effected by emissions . 

There is no discussion of the seasonality of atmospheric concentration levels . The behavior of 

PFOA in the environment is likely to be temperature dependent and therefore both diurnal and 

seasonal . It is also possible that there may be daily or seasonal cycles of surface deposition and 

reemission to the atmosphere of PFOA, particularly in summer. Air monitoring with diurnal time 

resolution is necessary to capture temperature dependent deposition and re-suspension cycles. 

Monitoring should be conducted in winter and summer so the dependence of atmospheric 

concentration on seasonal temperature extremes can be characterized . 

4 . The data set used to evaluate the dispersion modeling is inadequate. 

Model performance was evaluated against a data set that was inadequate for the reasons listed 

above. The result that adding deposition to the atmospheric transport models did not affect the 

predicted atmospheric concentrations cannot be corroborated with the limited data set use' to 

evaluate the model. Since atmospheric deposition is assumed to be the primary environmental 

pathway for PFOA leading to transport to affected aquifers, wet and dry deposition should be 

measured directly. 
5 . There was no attempt to perform a mass balance. The monitoring and modeling cannot be 

assessed if there is not some attempt to see if all the released material can be accounted for in the 

environment . One way to accomplish this would be to perform inverse modeling. Another 

would be to extend the air monitoring in both the horizontal and vertical dimensions and attempt 

an empirical mass balance. Both modeled and empirical mass balances should be performed. 

3 . : .5 Data Needs 

Stack sampling is necessary to verify the emissions inventory. 

Vertical sampling is necessary to establish a three dimensional concentration profile and provide 

data for mass balance calculations . 

Extended horizontal sampling to distances where the influence of local sources disappears and 

PrOA levels repr:.sentative of atmospheric background levels are seen. 

Air monitoring at landfill sites is necessary to eliminate them as additional local sources Of 

airborne PFOA. 

Air monitoring with diurnal time resolution is necessary to determine daily temperature 

dependent deposition and detect deposition and re-suspension cycles. 

PFOA wet and dry deposition measurements should be part of the air mcn:`:oring program. 

Winter and summer air sampling is necessary to determine the temperature dependence of 

deposition and transport processes. 

Modeled and measured mass balance calculations are necessary to account for all emissions and 

validate the monitoring, modeling, and exposure assessments . 

Long-term periodic measurements are essential to establish a, baseline _`o: levels of PFOA in the 

environment and quantify the effectiveness of emissions reductions. 
3.2 Surface Water and Sediment 

Overview: The only actual surface water samples obtained and analyzed for PFOA were from 

the Ohio River, during three dates in 2002 . For purposes of this review the more extensive outlet 

emissions from the Site (Washington Works) and the companion landfills (Local, Dry Creek, and 

Letart) were included; some putative surface water samples appear to have been taken/analyzed 

from these landfills as well. These "outlet" samples were obtained at various time points, 

depending on location, from the early 1990s up to 2008 . 

The report does not list any other surface waters monitored. Further, there are no sediment 

samples in the report . The SLEA used mean Ohio River water PFOA concentrations averaged 

from 60 total samples, over half of which were below the analytical LOQ. 

It does not appear that we sufficiently understand the current emissions and pathways of PFOA 

migration out of the Site and thus the answer to the question in the charge appears to be negative. 

In addition, there is insufficient information or data to understand how historical emissions lead 

to the current contamination of groundwater that results in the primary route for human exposure. 

It could be that the historical contamination of off-Site groundwater could have occurred through 

multiple mechanisms in contrast to what is occurring at present . 

3 .2 .1 Ohio River 

In addition to air emissions indirectly impacting surface water, direct discharges of PFOA to the 

Ohio River through the site outfalls, erosion of soils and leaching and runoff from solid waste 

management units (anaerobic digestion ponds and river bank landfill) and runoff from the three 

landfill sites could contribute to PFOA contamination of the surface waters, especially the Ohio 

River. The Ohio River is a potential pathway of transport of PFOA from the site and the landfills. 

PFOA in the Ohio River has migrated downstream to public water supply well fields located 

adjacent to the Ohio River that are recharged by river water (as evidenced by high levels of 

PFOA in downstream public water supplies) . 

A quick calculation of potential Ohio River PFOA concentrations for 2002, when -5,000 lbs of 

PFOA were released via aqueous discharges (Fig 4.1), yields a well-mixed average value of 

approximately 0.025 ppb PFOA. This assumes an average flow rate of 100,000 cfs [data on 

Ohio River flow at Parkersburg : National Weather Service, Advanced Hydrologic Prediction 

23 
Service; 100,000 cfs is the 75-90 percentile flow rate, however, the river would be expected to 

have somewhat higher flow downstream.] The value of 0.025 ppb is helpful to keep in mind 

when comparing actual Ohio River data. 

Ohio River Monitoring (Phase 1) was carried out in the summer and fall of 2002 with specific 

dates of sampling June 27 (Thursday), July 10 (Wednesday), and October 17 (Thursday). No 

information was provided that outlined the rationale for selection of sample day, location, or why 

the sampling was spread out over five months. According to Figure 5.12 (with min/max values 

and sample number; total 50 samples), there were 12 Ohio River transects taken during this 

period with 3 transects above the Site, 5 transects within the two-mile radius, and four additional 

transects downstream as far as Racine Lock and Dam (-50 miles from Site). 

The report says Fig 5.12 data are tabulated in Table 5.12 but the table only has values for 

transects near the Site and Letart . 

PFOA values were ND above the Site, ND to NQ adjacent and immediately downstream of the 

site, below which PFOA was detected and quantifiable 50 miles downstream to Transect 12 (2 

samples; -0.100 ppb) with the highest value at Transect 8 where PFOA was -1 ppb. PFOA 

dissipation appears moderate since Transect 9 and 10, sampled the same day, had PFOA at 0.28 

ppb at the upstream location and -5 miles downstream it was 0.23 ppb. At transect 12, the 

furthest downstream sampled, PFOA values were -0.100 ppb. It is unknown why further 

locations downstream were not reported since groundwater had detectable PFOA at Pomeroy (60 

miles) and apparently even to Crab Creek (-90 Miles) where a GAC system was being installed 

(to be completed Sept 2008). The summary section in the report incorrectly reports that PFOA . 

was only detected "18 miles downstream". It is clear that PFOA was transported at least 50 miles 

from the Washington Works Site, and likely further given PWS contamination, though no surface 

water samples are reported further downstream than Racine. The lack of assessment of the extent 

of PFOA migration and exposure to downstream locations is a major omission in this report. 

It is puzzling that PFOA was ND or NQ at all locations near the Site though it is noted that these 

samples were all taken on June 27`h while the detects downstream were taken in July or October . 

Outfall 005 (Site discharge farthest downstream) had PFOA concentrations of 76.2, 36.3, and 17 

ppb on June 27, July 10, and Oct 17, 2002 respectively . It is noted that the PFOA discharge on 

July 11, 2002, the day after the river sampling, was 230 ppb. Despite this close proximity to a 

24 
well known source, lack of detection in surface waters collected within 200 feet of the outfall is 

surprising. Is this due to a one-time sampling event (e.g., when the plant was shut down or after 

heavy rains or a weekend)? Some explanation needs to be put forth as to why there was no 

PFOA in surface water in these three trar.sects next to the Site. If the data were not collected to 

represent annual average, or at least representative values (taking into account seasonal, annual 

and daily variations), estimates of average exposure from such measurements are subject to high 

uncertainties . 

Additional sampling was carried out at two dates in each of 2004 and 2005, in the Ohio River at 

and near the Outfall 005; for reasons unknown the outfall itself was not apparently sampled on 

those days. Near the outfall, i .e . 5 ft to 20 ft from the bank, PFOA concentrations were generally 

between 1 and 6 ppb with concentrations dissipating out to "300 ft from the bank". It is unknown 

what the specific transect, relative to the outfall, was sampled in the river. 

Overall, there were 68 samples included in the SLEA (Transects 1 to 12 from 2002 and 04/05 

samples near outfall 005), of which 39 were ND or NQ for PFOA. In summary, river water 

sampling was so intermittent, and lacking in information regarding time of day or week, plant 

operation, river flow etc, that it is difficult to have a sense of what the river water concentrations 

mean. 

3 .2 .2 Washington Works Outfall Data 

Extensive sampling is reported for four active (001, 002, 005, 105) and two historical (003, 007) 

aqueous discharge outfalls during the years 2001 and 2008; data are found in Table 5 .17 and 

Appendix 5 .9 . Current outfalls range along the Site from the most downstream part of the site to 

the most upstream. Outfall 005 reportedly has the most "volume" but no data is provided to 

support this. Site 001, apparently the most upstream outfall, which places it upstream of the 

Little Hocking Water Association supply field, had a mean PFOA concentration of 21 ppb (high 

of 79.2 ppb) while 005 itself had an average of 56 ppb (high of 879 ppb). The report suggests 

these outfalls are the only significant source of PFOA to the Ohio River. 
200 

PFOA 

(ppb) 

150 - max = 879 

100 

50 - 

0 +--- 

2000 2001 2002 2003 2004 2005 2006 2007 2006 2009 

Year 

Figure 1 . Summary of PFOA conceintration measurements at Outfall 005 . 

The figure above is the annual data for Outfall 005 showing the mean value in ppb (red line), the 

top of the box is the 75`h percentile and the bottom the 25`h percentile for PFOA; the maximum 

observed value and the number of samples are indicated. The data suggest significant variability 

in PFOA discharge concentrations and no clear year to year reduction, at least between 2002 and 

2004. The outfall data are generally consistent with the PFOA water emissions reported in Figure 

4.1 where emissions declined modestly between 2002 and 2006. The 2001 water emissions, the 

first year reported in the figure above, were much lower at -11,000 lbs than the 2000 emissions, 

which were reported to be -48,000 lbs . 

Note: Figure 3.6 indicates additional Washington Works Site surface water outfa;ls that were 

sampled on a weekly or monthly basis. These include outfalls 102, 105, and 305 . However, we 

were unable to find data presented for any of these outfalls . 

3.2.3 Landfill Surface and Leachate Analysis for Local, Dry Run, and Letart 

Outlets, streams, leachate pipes, and related samples appearing in Tables 5.18 to 5 .20 all indicate 

measurable quantities of PFOA, including occasional very high values such as 4200 ppb in the 

26 
Upper Pond at Letart . Both active and historical locations are indicated though it is unclear why 

some monitoring locations were deleted . For instance the Upper Pond at Letart had 11 samples 

taken between 1991 and 1996 (480 to 4200 ppb) but values after 1996 are not provided. 

Similarly, Lower Pond, also at Letart, was sampled between 1991 and 2000 (mean value -1200 

ppb), with nothing later reported. 

Both Dry Run and Local Landfills had mean PFOA concentrations in the l Os to a 100 or so ppb 

while Letart was the most contaminated with mean PFOA values for outlets LCH1 approaching 

800 ppb. All of these sites would have presumably contributed to off-site transport of PFOA, 

directly or indirectly, to the Ohio River. At Dry Run Landfill, one unnamed "stream" had 24 ppb 

PFOA measured in 1996 with the only other sample taken producing a value of 6.28 ppb (2005) . 

3 .2 .4 Other Surface Waters 

There are several surface water bodies within the 2 mile radius of the site which were not 

sampled and analyzed. These include lakes and ponds - e.g ., Washington Lake (found on the 

map, located near the site) - located within the 2 mile radius of the site . There also appears to be 

several ponds located in the farmlands within the 2 mile radius . Farm animals can drink water 

from such ponds and this would be a potential source to farm animals and food chain 

contamination . It thus appears that PFOA has not been monitored in any of the surrounding 

surface waters other than the Ohio River. 

3.2.5 Washington Works Site Potential for Additional PFOA Transport to Ohio River 

The Site Conceptual Model (Figure 1 .2) is inaccurate in at least one aspect, since it shows the 

Solid Waste Management Units or SWMUs to the south of the Fluoropolymer plant (away from 

the river), which is incorrect . The anaerobic digestion ponds (ADPs) and the Riverbank Landfill 

(RBL) are actually perched just above the river north of the plant itself. The figure biases the 

discussion around the potential for the SWMUs to be a source of PFOA to nearby surface waters 

(i .e ., Ohio River) through leachate or stormwater runoff. Note *hat the Chemosphere paper by 

Davis et al (2007; 67:2011-2019) leaves the SWMU out of their Figure 3 altogether. 

3 .2 .6 Sediments 

Sediment samples were not collected from any of the water bodies in or around the Site although 

there is a potential that runoff from several contaminated sites including the solid waste 

management units (SWMU) can result in the migration of PFOA. There is a need for monitoring 

27 
of sediments from the Ohio River near the outfall, upstream and downstream of the Site, and the 

three landfill areas to assess the migration of PFOA through sediment transport. Sediment data 

are also used in exposure assessment, for specific scenarios involving contact with sediments, 

e.g ., groundskeeper/maintenance workers at the site (e.g., SWMU) and in landfill areas or off-site 

recreational boaters, and trespassers . Furthermore, sediment analysis is important for the 

assessment of pathways of migration of PFOA from the site and the landfills . Sediments are also 

important pathways of exposure to fish and benthic organisms . Human exposure to sediment can 

occur as a result of incidental ingestion and dermal absorption. Because no sediment PFOA data 

are available, such exposures have not been assessed . 

3 .2 .7 Analytical Comment 

LC/MS/MS requires one to know the ions of whatever analyte is of interest. For perfluorinated 

carboxylic acids (PFCAs) analysis one has to specifically put in both a parent and a fragment ion 

for each analyte of interest. It is unfortunate that these analyses were done such that only the ions 

associated with PFOA were monitored by the mass spectrometer (MS) detector and apparently no 

other analyte of interest. It is surprising since many other relevant fluorinated chemicals, such as 

the suite of PFCAs C6 through C15 as well as PFOS, can be co-analyzed in the exact same 

chromatographic run simply by adding all the associated ions to the multiple reaction monitoring 

(MRM) table in the MS analysis set up. Therefore, the only additional costs would be for 

standards and interpretation time. Note that the simultaneous monitoring of the known suite of 

perfluorinated chemicals is now the norm and not the exception . Therefore, although our charge 

is focused on PFOA, we would be remiss if we did not recommend that LC/MS/MS analyses 

conducted in the future should include simultaneous monitoring of the relevant suite of 

perfluorinated chemicals to obtain the additional information that will likely be useful in the 

ongoing assessment of PFOA. 

3.2 .8 Specific Data Needs 

1) All figures/tables should identify locations and dates when samples were taken (e.g . 

PWSs in Table 5.11 & Fig 1 .3) . 

2) A few creeks and shallow water bodies (e.g ., Brinker Run for Letart Landfill and Lee 

Creek for Dry Run Landfill) that flow through the landfills and sediments in these creeks 

should be analyzed, as these creeks are conduits for PFOA to the Ohio River. High 

concentrations of PFOA are expected in these creek sediments and in water and several 
exposure scenarios are possible. Fish, sediment and water should be collected from these 

creeks for PFOA analysis and exposure assessment. 

3) Further Ohio River water sampling/analysis needs to be done to measure the extent of 

river water migration of PFOA emanating from the Site. Historical emissions, likely of 

high concentration, appear to have resulted in the contamination of the public water 

system at Crab Creek which is -90 miles downstream. This suggests that river transport 

is significant and likely has reached very far downstream. The river water samples taken 

to date have been few in number and apparently not coordinated with plant operations. 

Sufficient samples need to be obtained in order to capture an accurate assessment of 

annual emissions, how these vary by time of day, season, etc. The current data set, with 

respect to size and breadth, does not appear to be consistent with the significant historical 

emissions inventory from the Site. 

4) The RBL and the ADP SWMU need to be correctly represented on the Site Conceptual 

Model . It is important to obtain the necessary samples to demonstrate that PFOA is not 

currently moving f:om the SWMU into the Ohio River or to the River via subsurface 

migration northward. From a simplistic examination of the maps/aerial photos supplied it 

is difficult to imagine how PFOA could be released from the Site and be transported over 

90 miles downriver while not impacting the Little Hocking Water Association supply 

wellfield located 700 feet across the River. 

5) A detailed explanation is needed of how historical and current emissions inventories are 

obtained for both water and air emissions . 

3.3 Soil and Groundwater 

3.3 .1 Background 

Groundwater is a primary drinking water source in the study area, thus a major target of concern 

with regards to PFOA exposure. Therefore, assessing PFOA sources to the groundwater and 

ensuring that these sources ar:d their magnitudes are properly identified L critical in assessing 

current and future exposure. Groundwater contamination at this Site can occur through four 

primary pathways: (1) Wet deposition of air emitted PFOA and PFOA-laden particles onto 

surface soil followed by leaching through the soil profile into subsurface aquifers, with 

subsequent migration in the direction of groundwater flow; (2) leaching through the landfill into 

the aquifer ; (3) runoff from the landfill onto nearby surface soil followed by percolation through 

29 
the soil to the aquifer; and (4) recharge of PFOA-laden river water, which could include PFOA 

released from the upper silty and clay alluvial zone during pumping. Each of these 

pathways are discussed below with regards to whether or not the sources and the pathways at the 

Washington Works Site and subsequent impacted sites are sufficiently characterized for the 

purpose of assessing exposure, and what additional data are needed to fill the data gaps. 

The general routes of exposure have been defined and substantial soil and groundwater data have 

been collected. Overall, PFOA air emissions clearly contribute to contamination of drinking 

water via the air-soil-groundwater route, although the report leads to concerns that there may be 

additional PFOA transport modes to drinking water. For example, the wind characterization 

shown for the DuPont Washington Works Site (Figure3-3) shows that wind transport occurs in all 

directions, winds to the SW are presented as most prevalent . The report then states that 

"residences that are located downwind of the Site have higher concentrations of PFOA than do 

residences upwind of the Site." (page 47 in Data Report 1). However, Figure 5.7 shows PFOA in 

groundwater serving as a residential water supply at > 2 .5 ppb (orange and red circles) at 8 sites 

south and west of the site while there are 9 sites to the north and east. Although presentation and 

interpretation of results in the report are inconsistent, data presented later in the report specifically 

with regard to the Little Hocking Water Association (LHWA) clearly exemplifies the role of 

PFOA transport via wind from the DuPont Washington Work sites, even if not in the apparently 

more prevalent SW wind direction shown in the Rose Wind (Figure 3-3). The latter will be 

discussed in more detail in section 3 .3 .3 below. 

3.3 .2 Washington Works Site 

3 .3 .2.1 Landfill Areas. This site of about 450 acres includes the fluoropolymer manufacturing 

plant and a Riverbank Landfill (RBL) area that within it contains three former anaerohic digestion 

ponds, which both sit on the river bank north of the plant. The ponds managed liquid and solid 

wastes from the fluoropolymer manufacturing processes until 1988 when the pond contents and 

upper few feet of clay liner and pond berm material were removed, backfilled, capped with 

topsoil, and vegetated. Although in Section 4.2 of the DA Report 1, it states that solid wastes 

were taken off-site and incinerated, later it is clear that there were solid wastes placed in some of 

the on-site SWMUs. The RBL itself was utilized from 1948 until the late 1960s and handled 

waste that "could contain PFOA". 
The Riverbank Landfill and the Anaerobic Digestion Ponds are (were) located within the 

floodplain adjacent to the Ohio River and along the edge of the upper terrace. The Riverbank 

Landfill was closed and is covered with top soils and vegetated. The Riverbank Landfill and the 

ponds are supposed to be getting an engineered cap system that will eliminate exposure and 

prevent further infiltration and leaching of waste related materials . Depending on how this area 

sits on the riverbank, a cap for only limiting infiltration may not be sufficient, but the designs for 

this cap are outside the scope of this assessment report . If undisturbed, the aquifer under the 

Washington Works site would discharge to the Ohio River. The Anaerobic Digestion Ponds were 

closed and material removed (1988) ; however, according to the well data as late as 2003 as 

detailed below, there are still residuals in the underlying soil that are leaching PFOA. 

PFOA concentrations measured in soil, surface water (seeps), and groundwater near the 

Riverbank Landfill and the Anaerobic Digestion Ponds indicate that PFOA from the land-filled 

materials did migrate to on-site soil and groundwater. The report claims no groundwater has 

moved off the Site due to production well pumping of groundwater, specifically the Ranney Well 

located to the East of the ADP. A schematic of this is highlighted in the SCM (Fig 1 .2; see also 

Fig 3 .8) though as noted above, the location of the SWMU is incorrect since it is actually perched 

just above the river. Interestingly, the report states that the contents of the ADP ponds and the 

upper few feet of clay liner and pond berm material were removed in 1988. Ground water 

monitoring wells are arrayed around the RBL and the ADP in which two wells in particular (P04-

MW02 and R04-MW02) are located immediately north of the ADP in the narrow area between 

the Ohio River and the ADP itself. These two monitoring wells were in operation between 1998 

and 2003 and 1999 and 2003, respectively . These two wells were accessing groundwater from 

the "primary aquifer" and "perched water in clay" and ranged in PFOA concentration between 

8000 ppb (1998) and -44,000 ppb (2003) and from 9,000 (1999) to 309,000 (2003) ppb, 

respectively. The most recent monitoring well data provided for the 2 wells (2002-2003) (P04-

MW02 and R04-MW02 2002-2003 data in Appendix 5.9-Table B) show very high PFOA 

concentrations (104 to 105 pg/L). Also there are high concentrations (lOz to 103 pg/L) in a well 

that appears to reside within the former ADP (Figure 3-6; Q04-MW02). In addition, from Figure 

3.8 showing the draw down due to the pumping of the Ranney well, it is not clear if the water 

associated with the 2 wells north of the ADP are actually being captured by Ranney well 

pumping. Therefore, it is challenging to simply rule out the potential for significant transport of 

PFOA from the former ADP into the Ohio River and/or into groundwater moving to the North 
and potentially the Little Hocking Water Association wells. A targeted groundwater tracer test 

may prove worthwhile for clarifying this uncertainty. 

3 .3 .2 .2 On-site Wells. According to the report and the supporting appendices, pumping of three 

on-site well fields near and parallel to the river (the Rar.ney Well, the DuPont-Lubeck Well Field, 

and the East Well Field) lowers the groundwater level to below river stage causing the river to 

recharge the aquifer zones rather than what would normally occur, that is, recharge of the river by 

groundwater. A United States Geological Survey (USGS) report (#2004-5088) summarizing the 

Survey's geohydrology assessment and simulation of groundwater flow in the Ohio River alluvial 

aquifers, including the Parkersburg area, indicates that the intense pumping (- 4.78 million 

gallons of water per day) in the Parkersburg well field has resulted in a cone of depression in the 

water table that is approximately 2 miles long parallel to the Ohio River and 1 mile wide. Their 

simulations estimate that approximately 75% of the water pumped in the Parkersburg well field 

by design is derived from river water and only 25% actually captures water from the alluvium. 

Given that the majority of water in the Parkersburg well field is drawn from the riverbed, the 

simulations estimat° typically short 5-year time-of-travel distances . USGS estimates a 5-year 

time-of-travel-area of approximately 1 .18 mi2), which is generally considered to be confined to 

the riverbed and the areas between the cones of depression in the well field. For the Parkersburg 

upper silty-clay confining layer, hydraulic conductivities are relatively small (1 to 3 ft/d), thus 

small changes in the hydraulic conductivity of this confining unit have pronounced effects o=. 

simulated heads. 

The large cones of depression that result due to the intense pumping of the localized cluster of 

industrial wells on the river band and the Neal Island complicate groundwater flow and lead to 

questions regarding how good the capture is by these wells and what level of pumping must be 

maintained, etc. Assuming good capture in conjunction with closure and proper capping of the 

River Bank area, this should minimize recharge of the river with PFOA-contaminated 

groundwater. Groundwater modeling simulations calibrated for the site have been made to try to 

assess the effect of pumping on the Ohio River-aquifer flow paths, as presented in Appendix 3 .2 . 

With the pumping there is a ground water divide in the central part of the site (as also implied in 

the USGS report) such that groundwater flows to the east toward the East Well Field on the 

eastern side of the divide and to the west on the western side of the divide, which ultimately flows 

either north toward the Ranney Well, or southwest toward the DuPont-Lubeck Well Field. From 

the northwestern corner of the site, groundwater flows southeast toward the DuPont-Lubeck Well 

32 
Field. Overall, groundwater modeling results, which assume continuous pumping of the on-site 

production wells, show that the pumping of production wells at the site does not allow for off-site 

migration of water within the site aquifer, with the exception of some off-site migration 

potentially occurring in the northwest corner of the site due to Blennerhassett Island where the 

river is not cut as deep yet and only connects to the upper alluvial zone. Also pumping by two GE 

wells (ID 3 and 4) can induce offsite migration of groundwater at the NW corner of the site . 

Given the complexity of the site, the multiple wells being pumped, the changing dynamics of the 

Ohio River including a series of locks and dams that are operated to pool the river as needed, it 

may be an over simp:ification to assume that there is no off-site transport of PFOA-laden 

groundwater at the Washington Works site. Some targeted groundwater tracer tests should be 

done to test this assumptio:~ and remove the present uncertainty. 

3.3 .3 LHWA Site 

At LH`JVA, all wells are drawing from the lower alluvium, which is dvscribed as sand to gravel to 

silty sand and has a hydraulic conductivity of 100 to 300 ft/day (USGS report 200-5088). Several 

additional soil borings and monitoring wells were installed in the LHWA area to better 

characterize PFOA contamination and pathways; however, this information was not well 

synthesized in the report . Synthesis of the water monitoring data (Table 4.1 in Appendix 5.8), 

depth of the wells installed (review of the in-field recordings of the soil borings in Appendix 5 .8), 

and the soil concentration data with depth (Tables 4 .6 and 4.7 in Appendix 5.8) supports the 

finding that much of the PFOA present is likely from wet deposition (or wet deposition and 

runoff) followed by percolation into the soil profile and subsequently groundwater . 

Some of the key data sets compiled from multiple sections of the report and associated 

appendices are presented in Figure 2. Several observations are apparent . First, contamination is 

much greater in the shallow wells that are drawing water primarily from the upper alluvium 

compared to the deeper wells drawing water from the lower alluvium, which is being replaced by 

river water. Secondly, PFOA concentrations are much higher in the upper 0 to 1' interval 

followed by a decrease in concentration with depth with a small rise in concentration again 

somewhere in the 17-25' interval depending on the core. It is clear by the higher concentrations 

observed in the top one foot of the soil borings in 2006 that substantial PFOA air emissions were 

still occurring at that time (although to a much lesser extent) . Seeing small rises further down in 

the soil profile reflects the variable nature of weather-dependent wet and dry deposition coupled 

33 
p. 37 

0 

0 © 

o a a 

y n 

e 

N 

h 

w a 

a a 

O °' 

N 

N 

'0 .N 

4) > 

>Y 

O = 

L 

= 

U) -0 

N 

IM (A 

LL N 

7 O 
with evapotranspiration and potential variations in actual PFAO air emissions for which no detailed data 

were provided. PFOA is only weakly sorbed to soils, with a partition coefficient of order of magnitude 

comparable to that of benzene (PFOA organic-carbon normalized partition coefficient, K,,c of_ lOz 

reported by Higgins and Luthy 2006 and DuPont 2003). Thus it is expected that PFOA will move easily 

from the surface to the subsurface with rain events. 

Third, clearly there was still a considerable amount of recent PFOA deposition from the air as can 

be seen from the 2005 grass and surface soil data summarized in Figure 2, even though a twoorder magnitude decrease in PFOA air emissions occurred, from 29,900 lbs in 2000 to 3001bs in 

2006. In addition, rain sampling in August 2005 at a site (Station 5 in Figure 5.3) on or in 

immediate proximity of the LHWA had the highest rain concentrations (-53 ppt , Table 5.4) . 

Changes (which hopefully consistently reflect improvements) on an annual basis from 2000 to 

2006 were not detailed in the report, thus it is difficult to extract what the current air emission 

contributions are to present PFOA air deposition to soil . For example, how different were 

emissions in 2005 that parallel 2005 grass/soil data collection versus in 2006 which may parallel 

or contribute to surface concentrations noted in the 2006 soil borings? Such information would 

help to anticipate the expected impacts on surface soil, surface water, and subsequently 

groundwater from deposition of air-borne PFOA after 2006 at the LWHA site as well as in the 

radius known to be impacted by theses pathways. In the case of the LHWA site, the low elevation 

of the LHWA site means it is also subject to surface runoff of PFOA air emissions that are 

deposited on the higher elevation land north and northwest of the LHWA site. 

While air emissions by 2006 have dropped two orders of magnitude compared to 2000, the 2006 

sampling and analysis of plants near the facility show substantial PFOA concentrations on plant 

surfaces. Much of this mass was clearly from surface deposition and free to mobilize to the soil 

surface and percolate to the aquifer (based on the difference between analysis of washed and 

unwashed plant material) . Substantial concentrations were also measured in the surface soils in 

2006 (Table 5 .16 for the borings at LHWA), which indicates that regular deposition of PFOAbearing particles is still occurring within the current domain of `allowable' air emission and 

releases . Therefore, given the high mobility of PFOA, the current level of `permissible' emissions 

will continue to contribute to loadings in the subsurface and groundwater. This loading could be 

occurring for large distances away from the site in multiple directions. This adds support for the 

need for further data collection of PFOA and PFOA-laden particle air emissions within and 

beyond the current 2-mile radius outlined in the current analysis, including measuring current 

deposition at the LWHA site . 

35 
In addition to the Washington Works site emissions that were a topic of the DuPont report, during 

our site visit we learned of another waste disposal facility (Little Hocking Service Center) 

located just west (< 1 mi) of the LHWA site . This additional waste facility receives (or did 

receive) wastes that may contain PFOA for incineration from another DuPont facility. It is not 

clear if incineration is still occurring on this site or what other activities have occurred or are still 

occurring at this site . Current air emissions, where appropriate, should be assessed from this 

facility as they could contribute to the level of PFOA observed at the LHWA site through 

atmospheric deposition. At the same time the local meteorology needs to be better characterized 

to help develop better models for predicting the current levels in the local atmosphere. In 

addition, the DuPont report should include a clear summary of the past and current activities at 

the site as well as details on anything stored above or below ground at the site . If this is not 

known, a comprehensive survey should be performed and reported on accordingly. 

Although it does appear that PFOA air emissions have been a substantial contributor to PFOA 

groundwater contamination, a rough mass balance estimation would help to validate whether this 

route could indeed yield such extensive and high PFOA concentrations in groundwater. Also is 

should be noted that the presence of PFOA in rainwater alone is not sufficient proof of the airsoil-groundwater transport pathway given the essentially universal observation of PFOA in rain 

across North America (see Scott et al ., 2006). The absence of mass balance calculations for this 

transport pathway makes it very difficult to interpret the observed data and make inferences 

regarding likely past, present, and future trends in PFOA concentrations and potential exposures . 

Some of the data (e.g ., high PFOA concentrations in a deep soil boring in 2002 between LHWA 

and the river bank (LHWAS2 in Appendix 4.1) suggest that other sources may contribute, 

including the potential that pumping may have induced the flow of water from the river along 

specific flow paths, pulling with it contaminated water leaching from the Anaerobic Digestion 

Ponds. (The same process of pumping that causes the river to recharge adjacent groundwater, 

and has been proposed to minimize off-site transport of leachate from the Washington Works 

Site), may occur at the LHWA site as well. In places where the river water intersects groundwater 

naturally or where it is induced (e.g., by well pumping), sediment can serve as a PFOA source to 

groundwater. It is also plausible that this is a highly sorptive and/or impermeable lens at this 

depth but it was hard to decipher the boring log from 2002, which states that problems were 

encountered with the temporary boring . 
3 .3 .4 Local, Dry Run, and Letart Landfills 

In some cases the panel differed with some of the conclusions about soils underlying the landfills 

being sufficient to minimize leaching from the landfills ; however, since the landfills have been or 

will soon be capped, details of our concerns in this area with regards to `current' PFOA sources 

and emissions may not be warranted . Prior to capping, runoff or percolation of precipitation 

through the PFOA-containing materials released and leached PFOA to the bottom of the landfill 

and then followed the direction of water flow, including along the clay bottom of the landfill and 

into underlying clays and fractured bedrock below the landfill. Covering of the landfills should 

substantially reduce leaching from the landfill as some of the limited data show. 

The Local Landfill (three landfill cells) was covered in 1980 with low-permeability soil that 

reduced infiltration of precipitation. Surface water and leachate from these cells flow to leachate 

collection ponds, then to storm sewers on-site and discharge to the Ohio River. At Dry Run 

Landfill, a permanent engineered cap was constructed in 2007, which should eliminate 

precipitation infiltrating through the landfill . A GAC-treatment system was installed in 2006 that 

removes PFOA from surface water discharging from the landfill's permitted outlet. Leachate at 

the Dry Run Landfill is sump pumped and treated at the Washington Worksite. The Letart 

Landfill, which contributed the highest levels of PFOA, was permanently closed and an 

engineered cap installed in 2001, which again should eliminate infiltration of precipitation 

through the landfill . Concentrations from the landfill in 2002 (post cap) are still substantial in 

some cases (Table 5.20). In 2006, a GAC treatment system was installed to remove PFOA from 

surface water and leachate discharging from the site's permitted outlet into the Ohio River. It is 

not clear if recent data have been collected for the area under the Letart landfill ponds where 

historically high concentrations were noted, and if PFOA in these zones is available for transport 

to groundwater and off-site . Therefore, although covering and capping of the landfills has 

reduced leaching and much of the surface water and leachate is being captured and treated, some 

additional data are needed on the PFOA concentrations currently in the water-bearing aquifer 

zones that can migrate off-site to small streams. 

3 .3 .5 Comment on Ranking of Exposure Pathways Related to Groundwater for SLEA 

There have been three separate residential water supply surveying and sampling programs preand within Phase I and II to date, which included public works and private wells. For water 

supplies with ? 0.05 pg/L (initial sampling program) or > 0.5 pg/L PFOA (later sampling 

programs) levels, treatment systems were set up for the most part or alternate water sources were 

37 
provided. The range in concentration of PFOA measured in residential drinking-water supplies is 

from `not detected' to a maximum of 22.1 pg /L. However, in assessing exposure from this water 

source, a conservative approach was taken (concentration data from pre-GAC treated water were 

used), which typically may be considered a safer approach, except in this report, the relative 

importance of all other modes of exposure are being decided based on this conservative approach 

used for drinking water. As discussed further in Section 3 .6, this bias could result in 

inappropriately discounting other exposure pathways. Exposure estimates should be made for 

GAC-treated or alternate water supply versus untreated water before comparing drinking water 

exposures with other pathways . 

3.3 .6 Specific Data Needs 

" Additional data associated with potential contamination of groundwater and 

migration to off-site streams from the ponds and contaminated layers in or near the 

water-bearing zones under the former (closed and capped) landfills are warranted 

including some post monitoring of the water-bearing zones associated with the 

Riverbank Landfill and Anaerobic Digestion ponds that will have an engineered cap 

system. 

" Additional assessment as to whether or not pumping at LHWA induces any 

unexpected hydraulic connection between the groundwater associated with the 

Anaerobic Digestion ponds is suggested as well, given the high PFOA concentrations 

observed in the wells immediately north of the ADP even after pond material was 

removed. Modelling in conjunction with previously reported data from USGS for the 

Parkersburg region was used to how industrial pumping on both sides of the Ohio 

River affected PFOA transport on and from the Washington Works site . Validation 

of this modelling effort with the collection of additional data is needed to remove the 

current uncertainty that exists. Options include monitoring for PFOA of existing or 

new wells on the bank of the river, monitoring of water level measurements on both 

sides of the river to determine drawdown in conjunction with recorded pumping 

conditions. Further, tracer tests should be used to delineate potential pathways 

between the LWHA and former-ADP area in/under the river bed, which will 

significantly reduce the source of uncertainty associated with only a modelling effort . 

" Clarification regarding the potential off-site transport scenarios that may occur if 

pumping at the Ranney Well, the DuPont-Lubeck Well Field, or the East Well Field 

were to cease for some period of time is needed. 

38 
" During the site meeting, questions arose regarding underground injection wells at the 

WWP site, which were later confirmed in public records . Although this practice has 

ceased, it should be mentioned in the report as well as details on the characteristics ef 

the injections (what, when, how much, under what pressure) and what the potential 

was for migration (horizontally and verticully) 

3.4 Biota 

The review is focused on the accuracy, scientific quality, and adequacy of the data for PFOA in 

biota for evaluating biota as a pathway of PFOA migration and exposure by humans. In 

particular, the completeness of the biota PFOA data for screening level exposure assessment 

(SLEA) is evaluated. 

Three types of biological samples have been analyzed for the determination of PFOA levels in 

this study. These are fish samples (n=20 for the Site plus n=20 for the background), meadow 

voles (from Little Hocking Water Association, n=10), and grass samples (from off-Site and onSite locations). The PFOA data for fish filet have been used in human exposure assessment with 

anglers as receptors . The PFOA data for grass have been used in the extrapolation of 

concentrations that could be found on home-grown produce. Based on this extrapolation, homegrown produce has been identified as an important potential source of exposure in the local 

population. However, this extrapolation has introduced some uncertainties and the screening 

level exposure assessment (SLEA) has identified this data gap for future study and refinement. 

While home-grown produce and domestically produced milk have been identified as important 

data gaps (i .e . in the future data needs report), other biological matrixes which are potential 

pathways of migration of PFOA to humans in the vicinity of the Site have not been discussed. 

The following sections describe these pathways and resulting data gaps and uncertainties in 

SLEA for PFOA exposure from biological media. 

3 .4 .1 Farm produce and local population/farmers 

The overall conclusion of the SLEA is that ingestion of drinking water (both public service 

district and private sources) has been the greatest route of PFOA exposure by the local population 

'.within a 2-mile radius from the Site) . However, groundwater and surface water (from the Ohio 

River or other streams or ponds) may be used as a source of drinking water for livestock and for 

irrigating crops by local farms. Thus, locally produced meat, milk, farm- and home-grown 

39 
produces (fruits and vegetables), can be potential routes of exposure in populations which 

consume these products. Although the reports have argued that airborne deposition has been the 

only source of PFOA to crops and crop products, studies have documented that PFOA is 

efficiently transferred from contaminated soil to crops, including corn stalks, by systemic uptake 

(Stahl et al ., 2009 ; Archives of Environmental Contamination and Toxicology, in press) . Feeding 

of livestock with fodder and other crops grown on PFOA contaminated soils can result in foodchain transfer of PFOA in and around the Site and the landfill areas. Currently, no data are 

available for locally grown farm produce and home-grown produce (fruits and vegetables), meat 

(beef and poultry), milk and eggs. The "Future Data Needs Assessment Report" has 

acknowledged the existence of this data gap and suggested the need for future studies to address 

it . 

According to the USEPA, approximately 37% of households in the South have home gardens. 

Modeled exposure analysis has indicated that consumption of locally grown crops, meat products, 

and milk could contribute exposures similar in magnitude to intakes of PFOA obtained via 

ingestion of drinking water. A community exposure study conducted in the vicinity of the 

Washington Works Site (Little Hocking Water Association) found an association between serum 

PFOA and servings of home-grown fruits and vegetables (Emmett et al ., 2006). There are two 

potential data needs that have been identified in the SLEA report ; (1) locally grown produce from 

home gardeners and (2) locally produced milk to assess exposures in farmers and home 

gardeners. However, locally produced meat including beef, and locally produced crops (from the 

farms), have not been identified as potential routes of PFOA exposure to the local population. 

Farm produce and home grown produce in the vicinity of Dry Run Landfill and Letart Landfill 

were not studied for PFOA contamination . 

Overall, there are uncertainties in the estimation of exposure to PFOA by farmers and the local 

population who consume locally grown farm produces and home-grown produces. There is a 

need to determine concentrations of PFOA in home-grown vegetables and fruits, locally grown 

farm produce (including fodder), milk, and meat (beef and poultry) . This should be done not only 

for the homes located within a 2-mile radius of the Site, but also for the farms located along the 

Ohio River. Data for biota (farm produce, home-grown produce, milk, and meat) from the Dry 

Run Landfill and Letart Landfill are needed to accurately assess the exposures in these locatione . 

Thus there exist data gaps and uncertainties in exposure assessment for farmers and local 

populations consuming locally-produced food products . 

40 
A specific concern is raised in the specification of the root uptake model presented in Appendix 3 

of the SLEA. There uptake is modeled based on tbe'Kow', which is really not directly applicable 

for ionizables without considering several other parameters (pH, ionic matrix, type of ion), and is 

particularly inappropriate for a compound like PFOA. 

3.4 .2 Fish and Anglers 

The relative importance of consumption of locally caught fish (in the vicinity of the Site and the 

landfills) as a route of exposure to PFOA by anglers and others who consume locally-caught fish 

has not been adequately assessed in the SLEA. For the SLEA, data from two species, with a total 

of 20 samples (n=10/species ; largemouth bass and channel catfish), caught near Washington 

Works outfall in October 2005 have been used. No fish samples were collected from other 

surface water locations along the Ohio River or near landfills, although several of these surface 

waters are accessible to anglers and local populations . Filet data were used in the calculation of 

exposure point concentrations (EPCs). The more typical exposure (MTE) and reasonable 

maximum exposure (RME) values for PFOA in fish filet collected from the Site were 1 .4 and 2.7 

ng/g, wet wt, respectively . This value appears to have been derived by averaging PFOA 

concentrations found in fish from a background location (n=20) in addition to Washington Works 

facility samples (Table 5 .7 of data assessment and Table 3-2 of SLEA). Although no 

considerable difference was found for PFOA levels in largemouth bass filet collected near the 

Site's outfall and the background location, the representation of PFOA data from two fish species 

with a limited number of samples collected at one point in time introduces uncertainties in the 

exposure assessment. In other words, PFOA levels determined in the two species of fish 

(largemouth bass and channel catfish) may not represent conservative or health-protective 

concentrations for fish consumed by anglers in the study area. 

PFOA levels in fish can vary depending on the species, feeding habits, gender, and time of 

sampling (pre-spawning versus post-spawning). Largemouth bass and channel catfish samples 

were collected in October, which represents a post-spawning season. There is a consumption 

advisory for largemouth bass and channel catfish collected along the Ohio River (Ohio EPA, 

2008), including Washington County, which suggests that these fish may not represent what 

anglers would catch or consume. In a recent survey of Ohio River tailwater anglers, 51 % of 

anglers interviewed were fishing for multi-species, 1 % were fishing for black bass (includes 

largemouth bass), 5% for catfish, 15% for hybrid striped bass, and 27% for sauger and walleye 

41 
(US Fish and Wildlife Service, 2004). In order to obtain a representative EPC value for fish, 

PFOA data from two species (n=20) collected at one point in time are not adequate unless it has 

been demonstrated that PFOA concentrations are expected to be no higher in other frequently 

consumed species . The current estimate of PFOA exposure for anglers is not demonstrated to be 

conservative and may be an underestimation of the actual exposure. 

No data for PFOA in fish from waterbodies near the landfill areas (Dry Run and Letart Landfills) 

are available . PFOA data for fish from Lee Creek, in the general vicinity of the Dry Run 

Landfill, are not available . Fish tissue PFOA data from the Ohio River in the immediate vicinity 

of Letart Landfill are not available . The assumption that fish may not contribute to significant 

PFOA exposure (relative to drinking water) near landfills is not adequately justified, especially in 

the absence of data. For example, the current model suggests that PFOA exposure from fish 

consumption is 2 to 4-fold lower than that by drinking water in the vicinity of Letart Landfill 

(Page 6-6, Sec 6 SLEA report) . However, a two-fold increase in EPC concentration for fish 

(from 1 .4 ng/g to 2.8 ng/g) or a two-fold increase in ingestion rate would make the above 

assumption inaccurate. Furthermore, the SLEA is expected to provide a conservative assessment 

of exposures with a due consideration of all potential pathways of exposure. Several surface 

waters within the 2-mile radius of the Site have not been sampled for fish (e.g., Lake 

Washington) and these waterbodies are accessible to the local public and anglers . 

For the exposure assessment of PFOA by anglers (Table B-25 SLEA report), fish ingestion rates 

of 0.095 g/kg-day (for MTE) and 0.56 g/kg-day (for RME) have been used (for adults) . These 

values are based on the general population fish ingestion rates (6.65 g or 39 g for an adult 

weighing 70 kg/d; lhttti :ilwww.cpa .~,,ov/waterscience/fish/files/contiumation reportpdf). These 

values potentially underestimate fish ingestion rates for anglers . Ingestion rates of freshwater fish 

by subsistence anglers are provided in Table 10-84 of the USEPA (1997)'s Exposure Factor 

Handbook. The 95`" percentile value for subsistence anglers is 170 g/day (95"' percentile) and the 

mean fish intake rate is 59 g/day (Table 10-85 of EPA's Exposure Factor Handbook). The values 

used in the assessment are approximately 4- to 9- fold lower than the values suggested by the US 

EPA for anglers' typical ingestion rates. There is a need to evaluate differences in exposures 

between `subsistence' and `recreational' anglers and fish consumers. 

If a conservative exposure screening does not screen out the fish consumption pa:hway, a survey 

(of local anglers) would provide more reliable information regarding type and ±Frp.,quency of fish 

42 
species caught and the consumption amount. If the fish consumption pathway is carried through 

to the next stage of risk assessment, collection of several species of sport-fish and subsistence fish 

from several locations along the river (to take into account the migratory patterns of fish) at 

different seasons is recommended for the calculation of EPC. 

3.4 .3 Breast Milk and Infants 

Several population groups (receptors) have been identified for the SLEA. The exposure 

assessment considered adult, adolescent and child populations to reflect different behaviors and 

physiological parameters. One population group that is not identified as a receptor for the SLEA 

is `infants' . There is a potential for elevated exposure to PFOA by infants via the ingestion of 

breast milk of the local mothers. The serum levels of PFOA in the local population (e.g., 

population from Little Hocking Water Association - 423 ng/mL in 2004; Emmett et al., 20G6) are 

100-fold higher than the U.S. general population (4 ng/mL) levels . The SLEA has identified that 

there exists a relationship between drinking water concentrations and breast milk concentrations 

of PFOA and that infant exposures from the ingestion of breast milk might be similar in 

magnitude to the estimated drinking water exposures for children (Page 3-26). The early life 

stages are very sensitive to exposure to toxicants and it is important to provide information on 

exposure pathways and exposure levels in infants in the vicinity of the Site. There is a need to 

conduct a conservative screening analysis for infant exposures via breast milk based upon current 

conditions of emissions and treatment to determine if there is a need to collect breast milk 

samples in the area (in the vicinity of the Site and the landfill areas as well as some 

reference/background locations). 

3 .4 .4 Game Animals and Hunters 

Hunting and gaming has been identified as a recreational activity in the region. Among several 

receptor populations and sources identified for the SLEA, ingestion of game animals was not 

identified as a pathway of exposure. Ingestion of harvested game can be a source of exposure. 

However, no game animals have been collected and analyzed for PFOA. A few grass samples 

collected within 2 miles from the Site contained several tens to a few hundreds of ng/g 

concentrations of PFOA. Herbivorous animals (deer, rabbits) can be exposed to PFOA through 

consumption of grass and other plants . There is a need to conduct a conservative screening 

analysis for this pathway to determine if it is necessary to analyze PFOA in deer, rabbit, pheasani, 

turkey, quail, and duck for the assessment of exposures in hunting and gaming populadons. 

While home grown produce has been identified as a pathway of exposure, home raised game are 

43 
not considered as a pathway of exposure. Home raised game animals including chicken can be a 

source of human exposures to PFOA. 

3 .4 .5 Summary of Key Concerns Regarding Biota Measurements 

Overall, while it is acknowledged that considerable effort has been put forward in developing 

these reports and compiling all the available data from the Site, there are data gaps, especially in 

characterizing PFOA in biological media, which can play an important role in the migration of 

PFOA on and around the Site. Furthermore, biota can be an important pathway of PFOA 

exposure to the local populations . There is a need to determine concentrations of PFOA in 

several biological matrixes to accurately assess exposures . Although home-grown produce and 

domestically produced milk have been identified in the Future Data Needs Assessment, it is 

recommended that PFOA data for farm produce, home-grown produce, locally produced meat, 

milk, fish from surface waters, breast milk samples and game animals (game hen) are needed, to 

account for potential biological matrixes that would contribute to exposures. Several aspects of 

the SLEA, as described in the reports, require further, more-adequate justifications . For example, 

exposure assessment of PFOA from the ingestion of local fish by anglers involved several nonconservative assumptions on fish species, ingestion rates and concentrations in fish. These 

estimates have introduced uncertainties that could potentially lead to an underestimate of actual 

exposures by up to 1 order of magnitude. There is a need to refine the exposure models for fish 

consumption . Other biological media such as breast milk and game animals should be identified 

as potential exposure pathways to PFOA for certain subpopulations . Justifications are required to 

explain why these pathways are not considered in the current report and/or these pathways should 

be identified in the `Future Data Needs Report" for future study. 

3.5 Multimedia Fate, Transport, and Exposure Pathways 

The foregoing chapters of this peer consultation have addressed the assessment of PFOA levels in 

specific media. Here we consider multimedia issues in the reports, and in particular whether the 

report has addressed multimedia transport of PFOA such that the pathways of migration from 

release to exposure are adequately characterized on a screening level basis. 

For the pathways of migration from release to exposure to be adequately characterized on a 

screening level basis, we expect the following to be satisfied: 
1 . The major pathways of migration from the source to the exposure media should be 

identified. 

2. A basic understanding of the processes governing this migration and the major factors 

influencing these processes should be demonstrated. 

3. A semi-quantitative description of the mass flows along the major pathways of migration 

from the source to the exposure media should be presented. 

4. Sufficient fielu data should be presented to demonstrate that the basic understanding of 

the major processes and the semi-quantitative mass flow calculations are roughly 

consistent with ~he reality in the study area. 

Our conclusions can be summarized as follows: 

1 . The site conceptual model adequately describes many of the transport pathways to people 

living close to the source. However, neither the exposure to PFOA nor the pathways of 

migration for people living more distance from the plant are characterized . This deficit i ; 

judged to be particularly serious for the population exposed via river water downstream 

of the site . 

2. The site conceptual model appears to be factually incorrect in its placement of the 

SWMU and its correct location, on the rim of the river. The conceptual model also omits 

a potential transport pathway from the SWMU into the Ohio River and a pathway into 

groundwater that may also flow away from the Site. 

3 . Migration within media (air and water) has been addressed elsewhere in this peer 

consultation. There appears to be a basic understanding of some intermedia transport 

processes (e.g. river water to ground water). However, several intermedia pathways of 

migration of PFOA are not yet understood at a basic level. Deficits exist particularly 

regarding the transport of PFOA from surface soil to groundwater, and from air and water 

to food. 

4 . A semi-quantitative description of the mass flows along some partial pathways of 

migration is presented (e.g. from air to surface soil) . However, no assessment along the 

entire major pathways (e.g. air - surface soil - groundwater - drinking water) is 

provided. 

5 . Data were collected and assessed to evaluate the atmospheric transport and deposition to 

soil following emissions to air at the Washington Works site . Data were also collected in 

surface water, but no effort was made to assess the relationship between emissions to 

surface water and transport via surface water. Measurements were conducted that 

45 
supported the understanding of the relationship between atmospheric emissions and 

deposition to terrestrial surfaces, but no effort was identified that evaluated quantitative 

understanding of the link between atmospheric emissions and the levels in groundwater 

from the unsaturated or saturated zones. Measurements to assess the transfer of PFOA 

from air and water to food are fully absent. 

3.5 .1 Pathways of Exposure from the Site to Exposure Media 

The site conceptual model adequately describes the likely dominant transport pathways to 

exposure media close to the Site. These include emissions to air - atmospheric transport -

deposition to soil - transport to groundwater - contamination of drinking water / food, emissions 

to surface water - transport to groundwater - contamination of drinking water /food, and leakage 

from waste sites to groundwater - contamination of drinking water / food. 

However, the transport pathways to exposure media more distant from the site are not addressed 

in the reports . One of these is atmospheric transport beyond the study area - deposition to soil -

transport to groundwater - contamination of drinking water / food. A mass balance approach was 

not reported in assessing the atmospheric dispersion of PFOA emitted at the sites, and hence it is 

not possible to evaluate the degree of attenuation of PFOA deposition with distance from the 

plant. 

A second transport pathway to exposure media distant from the site is river water - groundwater 

- drinking water. This pathway should be given particular attention, since attenuation of the 

PFOA concentration in river water with distance from the sites is expected to be very low due to 

the persistence and hydrophilicity of the chemical. Since bank filtration is a common method for 

obtaining drinking water, this pathway could result in high exposures for populations distant from 

the Site 

3.5 .2 Understanding of the Processes Governing PFOA Migration 

Migration within media (air and water) has been addressed elsewhere in this peer cons~iltation . 

The key transport processes between media are : 

Water - groundwater 

Atmosphere - surface soil 

Surface sail - groundwater 

46 
Groundwater - drinking water 

Groundwater - food 

Atmosphere - vegetation - food 

Water - groundwater exchange of PFOA is postulated to be the consequence of advection of 

water between the two media, presumably with little retention of PFOA in solid material. The 

similar concentrations measured in groundwater and aquifer material (e.g . Appendix 4.1) makes 

this a plausible assumption. The presence of unexplained high levels of PFOA in soil with high 

organic matter (see below) suggests, on the other hand, that retention in sediment could be a 

relevant factor in this process. Nevertheless, this is an appropriate worst case approach for a 

screening level evaluation. 

Atmosphere - surface soil transport was assessed using the model AERMOD and good results 

were obtained, suggesting that there is sufficient understanding of this process. 

The informadon on surface soil - groundwater transport provided in the reports is inconsistent . 

In Appendix 5 .3 it is argued that the surface soil samples represent long term accumulation, while 

elsewhere in the report (e.g . Part 1, sections 4.3 and 5.2 .4) it is argued that PFOA is highly mobile 

in soil and will be washed out of surface soil in single rain events. This indicates that there is not 

a basic understanding of PFOA transport from surface soil into the sub-surface unsaturated zone. 

Transfer from groundwater to drinking water is not a controversial issue for these chemica!s . 

Information on the efficiency of purification techniques is available . 

There is very poor understanding of the transfer from groundwater to food. This is acknowledged 

in the reports . 

The transfer of PFOA from the atmosphere to grass is not sufficiently understood. Observations 

suggest that at least 75 % of the residues in grass are from atmospheric deposition (Part 1, section 

5.4 .4) while modeling suggests that it is just 1-5 % (Part 2, Table C-3). Consequently the 

transport from the atmosphere into food is also not understood. This is acknowledged in the 

reports . 
3.5 .3 Quantification of PFOA Mass Flows Along the Major Pathways of Migration 

A quantification of PFOA mass flow from the atmosphere to surface soil is presented in 

Appendix 5 .3 . However, no assessment along the entire major pathways (e.g . air - surface soil -

groundwater - drinking water) is presented. Here it would be important to differentiate between 

the contribution of current and past emissions to current exposure, and to assess how both the 

exposure and the relative contribution of current and past emissions can be expected to change in 

the future as a result of control activities . 

3.5 .4 Site-Specific Empirical Evidence to Support the Semi-Quantitative Understanding of the 

Major Pathways of Migration 

Water - groundwater 

The transfer of PFOA following air emissions to surface soil was studied and reported on in 

Appendix 5 .3 . Good agreement was found between predicted and observed concentrations in 

surface soils. This work is considered sufficient for a screening level assessment. 

Although information on PFOA emissions to the Ohio River as well as PFOA concentrations in 

the Ohio River is available, no effort was made to assess whether this information was internally 

consistent. If the levels in the river are higher than predicted from the emissions, this would give 

evidence of further sources, and vice versa. 

No empirical evidence was identified to support the understanding on PFOA transport from 

surface soil to groundwater (or rather, to resolve the contradictions outlined in 3 .5 .2) . Appendix 

4.1 presents evidence on the vertical distribution of PFOA in soil and groundwater at several 

locations . However, no evidence is presented on vertical fluxes and how these relate to chemical 

concentrations in surface soil and environmental conditions. 

No measurements have been done on pathways leading to food. This is appropriately identified as 

a future data need in the reports . 

3.6 Human Exposure 

Earlier sections of this peer consultation have addressed the adequacy of characterization of 

PFOA concentrations in exposure media. This section addresses broad issues related to uiilizing 

those data in estimating human intakes in the screening level exposure assessment (SLEA). We 

48 
begin by revisiting the conceptual exposure model and commenting on its completeness, and then 

address the general exposure assessment methodology, exposure point concentration calculations, 

specific exposure parameters, and the uncertainty analysis . We conclude our assessment by 

discussing how limitations in the exposure assessment may affect the reliability of the 

conclusions and identification of data needs. 

3.6.1 Conceptual Exposure Model 

Updated conceptual exposure models are described in SLEA Section 3 .2 and presented in SLEA 

Figures 3-3 and 3-4. With the exceptions noted below, the exposure pathways and routes of 

exposure included in the model appear appropriate, though in many cases they are not yet well 

developed for the local conditions. This is an essential component of a revised plan for exposure 

assessment and the collection of samples to appropriately support that assessment. The selected 

receptors also represent an appropriate range of activities by which people might contact the 

affected exposure media; however, no effort was made to sample time-activity patterns of the 

local population, or to validate the appropriateness of the selected receptors to behaviors 

exhibited by those potentially exposed to releases from the Site. Generally, Figure 3-3 provides a 

clear pictorial description of PFOA release and transport processes (although, as noted above, the 

location of the ADP and RBL is incorrect and misleading) . Consistent with standard risk 

assessment methodology, Figure 3-4 documents the exposure media and exposur2 routes relevant 

for the various receptors . For each receptor/exposure medium combination, symbols indicate the 

completeness of the exposure pathway and data availability . Several comments are provided on 

this figure : 

" According to the figure domestic use of groundwater is anticipated to result in both 

ingestion and dermal exposures . Inhalation exposures are not included. We recognize 

that PFOA is water soluble and typically present as an ion, and consequently not 

expected to volatilize from hot water; however, inhalation should still be included in the 

conceptual model with a note regarding the limited potential for exposure via this route. 

" For sediment, for all receptors both ingestion and dermal exposures are reported as being 

either incomplete (i .e ., or potentially complete but with expected exposures less 

than other receptors (i .e ., "O") . This is not logical . A shaded circle or black circle must 

apply to at least one receptor for this medium. We recommend that shaded circles be 

applied for both the offsite swimmer and offsite angler for ingestion and dermal contact 

with sediment. 
" As described above, it is recommended that consumption of game and exposure of infants 

via breast milk be added as exposure pathways. 

3.6 .2 General Exposure Assessment Methodology 

The general approach used in the SLEA is consistent with EPA guidance for calculating intake 

estimates for use in risk assessment. The main limitations in the general methodology are that i) 

the SLEA does not make sufficient effort to obtain and use local exposure concentrations, and 

exposure factors and behaviors for the local population; and ii) the SLEA does not explain how 

the resulting intake estimates will be used in assessing risks. These issues are each addressed. 

A Screening level exposure assessment for perfluorooctanoic acid (POFA) was completed by 

Environ to provide a first-order analysis of potentially completed exposure pathways (media) and 

exposure routes ( entry into the body) among the three sites that were the subjects for study. The 

sites used in the analyses were the Washington Works Facility and Local Landfill, the Dry Run 

Landfill, and the Letart Landfill . In each case the screening exposure characterization suggested 

drinking water to be a major route of exposure to PFOA. The estimates for drinking water are 

based upon site data, and the authors used various assumptions (some of which not explained) 

about whom and how they would be exposed to PFOA. Little or no data are available for the 

other exposure pathways (e.g . air, soil ingestion, food etc.) 

The authors used information from EPA guidance documents during the completion of their 

analyses, and applied general exposure factors to replace missing or unavailable information and 

data. Five or six types of individuals were selected as the target receptors at each location . These 

included: offsite resident/home gardener, offsite resident farmer, offsite commercial worker, 

offsite creek visitor or recreational visitor, offsite angler, and offsite recreational swimmer. For 

the drinking water route of exposure these are reasonable populations . However, many of the 

activities and the frequency of activities used to estimate exposure to these hypothetical 

individuals were speculative. All calculations are based upon a reasonable maximum exposure 

(RME) or mean typical exposure (MTE) to represent high end and central tendency levels of 

exposure, respectively. In principle this analysis plan was a logical undertaking. 

At the present time, there is no information provided in the document that assists in providing a 

validation for the baseline assumption used for each "receptor" person/population. In most cases, 

the analysts use national data on percentages or frequency of activities to base their exposure 

50 
estimations for each location, but fail to describe the uncertainties associated with applying these 

assumptions to the population being evaluated. Demography and land use patterns in the study 

area are not given. There is a need to describe demography and land use patterns to evaluate if 

the SLEA is appropriate and covers all of the population in the region. The demographic 

characterization should describe the population distribution, industries and occupations, 

agriculrural land use, livestock production, anglers and type of fish, game animals and hunters. 

Further, as described in earlier sections, there is limited PFOA concentration data available for 

exposure routes other than drinking water in two of the three locations (the Dry Run landfill, and 

the Letart Landfill) . The available PFOA data were collected primarily around or near (within 2 

miles of) the Washington Works Facility, and some data were available for multiple exposure 

pathways. However, the number of data points is limited for some pathways even for the 

Washington Works Facility site, e.g . fish. No PFOA air concentration or fish concentration data 

were available for the other two locations . Further, data were not collected for PFOA in 

homegrown crops and other food product at any of these locations . As a result, extant data were 

used in the analyses, but not from locations of similar character. For the homegrown food 

consumption estimates, there is no justification provided for the assumption that the national 

values used would be reliable for estimating exposure in a location near a major source of PFOA 

or a site of PFOA disposal. The authors rely on modeled estimates of PFOA concentrations in 

home grown food, meat and animal products (milk, and edible fish) . For produce the model 

includes direct deposition and root uptake based on soil and groundwater EPCs. Since it is clear 

that drinking water can be a major pathway for exposure, consideration of the use of local tap 

water contaminated with PFOA in the preparation of food should be addressed, in addition to the 

uptake while food is being raised . The lack of data for site-specific exposure characterization is 

also identified as a limitation of the current study in our review of other media concentrations, 

including biota, presented above. 

Except for drinking water, which has a reliable database for estimating local exposure at all three 

locations, most of the data and estimates are presented as part of an uncertainty analysis. While 

an uncertainty analysis is certainly appropriate, it must first be preceded by a thorough 

documentation of what was done to obtain as much local data as possible, and how these date 

were used to obtain best estimates for the targeted exposures . Unfortunately, there is little or no 

local data that was collected or used to serve as a basis for many of the exposure route estimates 

completed for each location . Local data were neither used to estimate PFOA exposures for most 

51 
routes considered, nor to validate and compare against the national estimates that were generated . 

This raises questions regarding the significance of other (non-drinking water) exposure pathways 

and the levels contributed by different pathways to one or more of the routes of exposure. The 

information base for the exposure assessment is not site specific, which is a major weakness that 

permeates the screening exposure characterizations. What actually is required are sampling 

programs to collect data for the observed routes of exposure. Such data could be used to support 

or contradict the conclusion of an uncertainty or sensitivity analysis . 

The SLEA is also generally lacking in any discussion of background exposures to PFOA in the 

general U.S. population as a separate section that is divorced from the site specific exposure 

assessment. This information is needed to properly assess incremental exposures associated with 

the site . Information on PFOA in packaging and PFOA released by various cooking utensils and 

practices would be a valuable addition to any revised analysis plan to deal with confounders in 

the analysis of contributions associated with food consumption . A list of confounder sources that 

will have PFOA also needs to be identified to determine the significance of the local 

contributions versus the general contributions to PFOA for many different exposure pathways and 

sources. 

The different activities selected to represent the receptor populations need additional 

documentation. This could be accomplished by a survey of the population to see if, for example, 

people do swim in the Ohio River, fish in the Ohio River and eat the caught fish at the 

frequencies defined by the analysts. Further, it would be interesting to see what percentage of the 

population eat home grown or raised food and animal products that is contaminated by PFOA. 

Local surveys are needed for these and related exposure factors . 

The calculations of intake dose after exposure do not take into account variation in relative 

bioavailability of chemicals in different exposure media and, at a minimum, known physiological 

factors about absorption for different routes of contact . In all cases the authors assume a default 

relative bioavailability value of 100%. This may be an incorrect assumption, and can lead to 

overestimation of the potential dose. On the other hand, an activity, showering does not include 

inhalation of PFOA, and swimming does not include dermal absorption (See table B .1 in the 

report) . Dermal effects have not been observed for some workplace populations so the dermal 

contact may be deminimus for irritation, but how well is it absorbed? This can influence the 
significance of bathing or showering on the internal dose. The potential impacts of these 

uncertainties should be addressed in the SLEA. 

The panel also notes concern regarding the estimation of the dermal exposure permeability 

coefficient . For exposure assessment by dermal contact through surface water (while swimming), 

a Kp (permeability coefficient) value of 1 .5 x 10~6 cm/hr has been used. This value was obtained 

from an in vitro study (which does not represent dynamic in vivo conditions of body temperature, 

blood circulation, pH, etc that a swimmer would experience) based on the reference Fasano Pt al. 

2005. The study by Fasano et al, used APFO, not the PFOA anion. As the report has indicated, 

there are differences in the behavior of these two forms of PFOA. Furthermore, the APFO 

concentration used in the in vitro study was 20% salt, not environmentally relevant ppb or ppt 

level water concentrations . Fasano et al . have cautioned in their article that "in vivo predictions 

using an in vitro derived value should be used with caution until an appropriate in vivo validation 

study (e.g ., an in vivo dermal exposure with measured blood levels of A.~'~FO) is conducted". 

Owing to this uncertainty associated with the use of this Kp value in the exposure assessment 

from surface water, the value should be deemed non-conservative or an underestimate of the 

actual exposure. An assessment of exposure using such laboratory-based in vitro values would 

require inclusion of uncertainty factors . 

3.6 .3 Interpretation of Significant Exposures in Light of Potential Health Risks 

For most chemicals intake estimates are combined with inhalation and oral toxicity values to 

estimate cancer and noncancer risks for inhalation and for ingestion and dermal contact 

combined. There are no generally accepted toxicity values for PFOA, so reliance on the standard 

approach would rely on the development of such values. Alternatively, it could be possible to 

combine the intake estimates with a PBPK model to predict serum PFOA levels . The serum levels 

could then be compared with both background levels and levels suspected of causing adverse 

effects in humans. The lack of information regarding how the exposure estimates will be applied 

may lead to incorrect conclusions in the SLEA. For example, the conclusion that inhalation 

exposures are low compared with other exposure routes is irrelevant if the lung is a target organ 

and inhalation risk will be assessed separately from ingestion a~~d dermal exposure. 

Other concerns we have with the analysis include : 

0 the lack of detail provided to document specific exposure parameters, 
" the lack of objective analysis of the relative degree of uncertainty for the different 

exposure pathways, and 

" conclusions about the relative importance of different exposure pathways that fail to 

acknowledge present reduction in drinking water exposures due to treatment of 

groundwater prior to use. 

The reliance on comparison with drinking water exposures as a basis for discounting the 

importance of other exposure pathways is particularly problematic and misleading. We 

understand that the intent is to assess the current drinking water status in the next iteration of this 

document, but this document should not appear to discount the relative importance of other 

exposure pathways based on a comparison with drinking untreated groundwater because that 

comparison does not reflect current conditions with widespread water treatment in place, i .e., 

pathways that seemed minor compared to drinking water exposures prior to water treatment, may 

now contribute a much greater fraction of total exposures . 

To address this issue, we recommend that the executive summary and introduction specify that in 

this document "current" exposures are defined as those occurring during the five-year period 

from 2002 through 2006. It should also be noted in these two places that a subsequent analysis 

will address exposures following the installation of water treatment systems. We recommend that 

the next analysis also consider the variation in drinking water exposures based on variations in 

the effectiveness and variability of water treatment over time for both public water systems and 

private well users. 

The five year exposure duration used in the SLEA is a departure from standard risk assessment 

approaches and also requires an early explanation in the document. Most risk assessments use a 

longer exposure period to assess chronic exposures . Again, because the risk assessment approach 

has not been described the implications of the use of a subchronic exposure period are not clear. 

Assuming only noncancer endpoints will be evaluated, and using an averaging time matched to 

the five year exposure duration, the estimated intakes should still provide an accurate indication 

of exposure. However, this needs to be explained. The only way the panel could determine that 

the correct approach had been ased was to comb laboriously through Appendix B to find the 

averaging times used. 
3.6.4 Exposure Point Concentration Calculations 

As described in the SLEA Appendix B (Section B.1), EPCs were calculated using standard EPA 

ProUCL tools, except that the distributions of the datasets were not tested . Instead nonparametric 

methods were used, specifically the bias-corrected accelerated (BCA) method using the KaplanMeier approach. Also in some cases mean values were used as inputs to ProUCL for individual 

sampling locations with more than one sampling result. Overall, review of the exposure 

concentrations presented in Table B-4 suggests that the method used to calculate EPCs has a 

limited impact on the values used on the SLEA. 

In contrast, as noted in Section 3 .6 .2, the modeled EPCs for produce, crops, meat, milk, poultry 

and eggs have a high degree of uncertainty and do not consider the potential added exposures 

from pceparation of food using contaminated tap water. 

3 .6 .5 Specific Exposure Parameters 

As has been described above, in many cases inadequate documentation is provided to determine 

the conservatism of specific exposure parameters. The significance of this limitation is that it :s 

not readily possible to asses the reliability of comparisons among exposure pathways. Appendix 

B (Section B.2 and associated tables) includes summaries of exposure parameters and notes 

regarding sources for the values selected ; however, there is no discussion to support or justify the 

values. While some of the values selected are default values typically used by EPA at most sites, 

others are known to vary greatly from site to site . For example, the residential soil ingestion rates 

selected are those typically used by EPA, and their degree of conservatism can be directly 

assessed. In contrast, there are no widely applicable consumption rates for fish, homegrown 

produce and other local foods that can be applied at all sites without discussion to describe the 

rationale for their selection for a specific site . The reader of the SLEA cannot readily determine 

if the selected values are adequately conservative to capture the range of likely exposures. This 

deficiency directly limits the ability of the PCP to determine if there are critical data gaps 

associated with these exposure pathways. 

3 .6 .6 Uncertainty Analysis 

The SLEA is essentially a pathway screening analysis . For that reason the uncertainty analysis 

should include detailed discussions for each pathway and related routes of exposure that describ° 

the underlying uncertainties in the available data and exposure parameters. Consistent with EPA 

guidance for uncertainty analyses, the discussion should specify the decisions made to address 

55 
these uncertainties, and the impact on the degree to which the resulting exposure estimates may 

over- or under-estimate exposures . We understand that a summary of this sort is provided in 

Table 6-1 (to support the data needs assessment) ; however, that table does not address uncertainty 

in the exposure parameters, and also does not clearly address the overall degree of conservatism 

in the exposure estimates . 

For example, soil ingestion is not mentioned in the uncertainty sections and Table 6-1 indicates 

only that there is low contribution to intake, that a limited downwind dataset was conservatively 

applied to areas lacking soil data and that there is medium level of uncertainty in the dataset . The 

uncertainty sections should note the dataset limitations as described in Table 6-l, but should also 

describe the key assumptions for exposures parameters. These would include noting that the 

default EPA soil ingestion rates are likely to overestimate chronic daily soil ingestion rates, 

particularly at the upper percentiles used for the RME, and also that it was assumed that all 

ingested PFOA would be systemically absorbed, comparable to absorption of dissolved PFOA in 

drinking water, an assumption that may overestimate exposure substantially . 

The uncertainty analysis should be the primary tool available to the PCP to understand which 

exposure pathways screen out, and therefore, do not need additional data collection or analyses to 

more fully characterize migration and exposure to PFOA (as directed in the charge). The absence 

of a comprehensive uncertainty analysis limits the ability of the PCP to execute the charge. 

3.6.7 Conclusions and Identification of Data Needs 

Major findings regarding the SLEA include the following: 

1 . Except for possibly drinking water, the screening exposure analysis does not appear to 

represent the local community "situations" since most of the data that are used are from other 

locations and would not be representative of any of the three sites . 

2 . The exposure analysis receptor scenarios selection process has not provided informaion on the 

actual local behaviors of the population that support the selected activities . The applicability anc 

degree of conservatism of the assumptions used must be articulated . 

3. The EPCs for PFOA found in food is based on deposition and uptake models. Local data on 

PFOA in home grown and raised foods are necessary, and the consumption practices for local 

foods need detailed evaluation for use in the exposure assessment. 
4. The RME and MTE estimations use many assumptions that are not valid or justified for the 

local situation . Further, no effort has been made to tie the screening results to a known acute or 

chronic health outcome. What do the values for the RME or MTE mean in terms of potential 

health effects? There is no health slope factor or referenced dose provided, or comparison with 

data available from other locations where health effects have be demonstrated after exposures to 

PFOA have been identified. 

5. There are PFOA data and questionnaire information available from the C-8 study for the lccal 

area. Further other studies external to the local area that can help to define the exposure issues 

and data needs more clearly are needed to conduct a screening analysis . A focus of attention 

should clearly be on proving that a major source of local exposure is drinking water. 

6. The Washington Works Facility and Local Landfill should be the focus of any immediate 

revision for screening characterization since there are actual data available. Concurrently, the 

data needs must be thoroughly discussed and weaknesses removed with a better PFOA data 

collection plan. 

7. Any revisions to the Dry Run Landfill, and the Letart Landfill screening exposure 

characterization must include a logical plan for data collection and re-analysis is finalized for the 

Washington Work facility that can be used in each of these locations . 

8 . The screening exposure assessment should be forward looking in perspective, and utilize the 

extensive biomonitoring data in the population that now receives the drinking water through the 

Little Hocking Water Association, other public systems and from private wells. The 

biomonitoring data should offer insights regarding the variability in exposures . The conceptual 

model for exposure needs to consider additional sampling based upon the recently established 

emissions from the stacks, and develop air and biota monitoring programs that can achieve the 

goals of a revamped program. 

Section 6 of the SLEA presents the evaluation of potential future data needs. If the suggested 

changes are made to the uncertainty sections, the conclusions and identification of data needs can 

draw on the uncertainty assessment to make the basis for conclusions clearer. Our particular 

concern with the data needs discussion and Table 6-1 is the reliance on comparison of intakes 

from other exposure pathways with drinking water intakes to determine the relative contribution 

to intake. For example, Table 6-1 indicates that beef, poultry and eggs do not represent a data 

need because the screening model suggested intakes from these foods is 3 to 10-fold lower than 

drinking water intake . This logic is not relevant due to the present situation in which drinking 

water exposure for most residents has apparently been markedly reduced. Consequently, these 

57 
pathways could currently be contributing a substantial relative proportion to present day 

exposures . Section 6 and Table 6-1 must be revised to screen pathways without relying on 

comparison with drinking water intakes from 2002 through 2006 . 

3.7 Summary of Priority Data Needs for Future Study Phases 

Ir. anticipation of future data collection for PFOA characterization at and near the Site, we 

attempt here to describe what we believe to be the highest priority areas for further monitoring 

and modeling. These are reviewed below and may provide useful input in the design of Phase III 

studies for the Site. The recommended measurements include data needed to provide both better 

resolved estimates of exposure for the local populations, as well as for performing a mass balance 

calculation of historic and current PFOA emissions and environmental inventories. 

3 .7 .1 Comprehensive Air Monitoring 

PFOA air emissions were and appear to still remain a large contributor to contamination of 

drinking water via the air-soil-groundwater route, especially within a few mile radius of the site 

and possibly beyond. Although DuPont reports a substantial (two-order-of-magnitude) decrease 

in air emissions by 2006, the amount of PFOA actually being emitted now or in the past is not 

reported. Without this information, it is not possible to perform mass balance calculations for 

transport through the surrounding environment . A coordinated, ongoing air monitoring program 

is needed, including time coincident measurements of emissions, ambient concentrations, and 

deposition. Monitoring should include direct stack, ambient, and deposition monitoring at time 

scales sufficient to characterize long-term, seasonal, and diurnal variations in PFOA emissions, 

concentrations, deposition, and resuspension. Spatial resolution should be sufficient to address 

vertical variations in concentration that inform flux-deposition processes, and horizontal 

variations across key receptor locations, including the Ohio River, the LHWA well field, and 

more distant locations needed to determine the spatial extent of the Site influence. Air sampling 

should be extended to distances (horizontally) where the influence of local sources disappears and 

PFOA levels representative of atmospheric background levels are seen. This strategically holistic 

data set will not only quantify current emissions and exposure, but when coupled with a mass 

balance modeling approach (see Section 3.7.6 below), will enable the estimation of 

environmental loadings and exposures associated with historic e:nissions . 
3 .7 .2 Spatially Extensive Surface Water Monitoring 

A spatially comprehensive synoptic survey of PFOA concentrations in the Ohio River is needed 

to characterize the spatial extent and source-receptor relationships of water quality impacts from 

the Site. Given the small number of randomly collected Ohio River water samples that contain 

detectable levels of PFOA, a more-targeted sampling campaign should be pursued to address the 

extent to which fugitive emissions of PFOA travel downstream of their entry point. The 

sampling should be done, if possible, during one day to provide a snapshot of Ohio River 

contamination. The sampling day would necessarily be planned for a time period when actual 

releases are occurring at the Washington Works Site. Specific samples should be obtained in the 

immediate vicinity of each of the major outfalls and downstream, in line with the current (as 

opposed to a transect running perpendicular to the bank), and should extend downstream as far as 

possible, but in any case should include areas known to have drinking water contamination (e.g. 

at least as far downstream as Crab Creek or -90 miles) . Water samples and attendant sample 

concentrations should be constructed to yield quantifiable PFOA concentrations in all surface 

water samples. A few creeks and shallow water bodies (e.g., Brinker Run for Letart Landfill and 

Lee Creek for Dry Run Landfill) that flow through the landfills and sediments in these creeks 

should also be analyzed, as these creeks are conduits for PFOA to the Ohio River. High 

concentrations of PFOA are possible in these creek waters and sediments . Coincident fish, 

sediment and water samples as part of the synoptic water quality survey. 

3 .7 .3 Intensive River Sediment Sampling 

Bottom sediment samples need to be obtained from the Ohio River in areas immediately adjacent 

to Washington Works outfalls, upstream, and downstream, as well as downstream of the landfill 

sites . Transects should be designed to capture the extent of PFOA contamination related to a 

specific outfall and should include differential depth analysis . A related need is to sample a 

sediment transect running from the Site across the river to the LHWA. This transect would be 

designed to detect the existence of any seepage zones emanating from the Riverbank Landfill 

(RBL) that could potentially have released PFOA that subsequently migrates to the LHWA. 

Careful study and design will be needed to determine the appropriate depth(s) of sediment 

retrieval along with monitoring of the water-bearing zones associated with the Riverbank Landfill 

and Anaerobic Digestion ponds pre and/or post instalment of an engineered cap system, to 

thoroughly examine this potential PFOA transport pathway. 
3 .7 .4. Groundwater Pump and Tracer Tests 

Pump and tracer tests are needed to further explore possible hydraulic connections between the 

Ohio River waters near the Site and groundwaters on both sides of the river. These are needed to 

support assessments of the potential for off-site transport scenarios that may occur with changes 

in pumping of the Ranney Well, the DuPont-Lubeck Well Field, or the East Well Field, and 

whether or not pumping at LHWA induces any unexpected hydraulic connection between the 

groundwater associated with the Anaerobic Digestion ponds and waters that eventually enter the 

LHWA well field. Modeling in agreement with previously reported data from the USGS for the 

Parkersburg region indicates a groundwater divide under the Ohio River, which inferred minimal 

PFOA transport off the Washington Works Site. However, this modeling effort is in need of 

further validation, given the very high PFOA concen:rations observed in the wells immediately 

north of the ADP (even after pond material was removed) and what appears to be increases in 

PFOA concentrations in the water being pumped out by the LHWA. The latter may be due to 

only contributions from wet/dry deposition and run off down the west slope of deposited PFOA; 

however, sufficient uncertainty warrants further data collection. Options include monitoring for 

PFOA in existing or new wells on the bank of the river and monitoring of water level 

measurements on both sides of the river to determine drawdown in conjunction with recorded 

pumping conditions. Further, tracer tests should be used to delineate potential pathways between 

the LWHA and the former-ADP area in/under the river bed. These pumping and tracer studies 

should significantly reduce the uncertainty associated with these potential groundyvater-river 

water pathways. 

3 .7 .5 Additional Biological Monitoring 

There is a need to determine concentrations of PFOA in several biological matrixes to accurately 

assess exposures via biota to local populations. Although home-grown produce and domestically 

produced milk have been identified in the Future Data Needs Assessment, it is recommended that 

PFOA data also be collected for farm produce, locally produced meat, fish from surface waters, 

breast milk samples and game animals (game hen). These studies should be conducted in 

conjunction with ongoing biomonitoring surveys of the local population to better coordinate 

exposure and biomarker estimates. These studies could potentially point to other environmental 

media and routes of exposure requiring sampling and characterization, such as household dust or 

water distribution systems downstream of centralized water treatment. 
3 .7 .6 Implementation of Multimedia Model to Evaluate PFOA Mass Balance in Nearby 

Environment 

A multimedia mass balance modelling approach should be used to synthesize the available 

information on PFOA_ mass flow and PFOA mass inventory. This modelling should incorporate 

available mechanistic understanding of the transpert and behaviour of PFOA in ail relevant 

media, and address changes in emissions, transport, inventories and exposure over time. It should 

be used to test whether the available information gives a consistent and sufficiently resolved 

picture of PFOA exposure pathways related to the facility, and to identify and define future data 

coilection nePds. 
References 

DuPont. Adsorption/Desorption ofAmmonium Perfluorooctanoateto Soil (OECD 106); E.I . du 

Pont de Nemours and Company: Wilmington, DE, 2003, U.S. Environmental Protection Agency 

Docket OPPT-2003-0012-040. 

EFSA, 2008 . "Opinion of the Scientific Panel on Contaminants in the Food chain on 

Perflosoocatane sulfonate (PFOS), perfluorooctonoic acid (PFOA) and their salts", The EFSA 

Journal (2008) 653, p61 ., European Food Safety Authority, 

httn://www.cl'sa .curopaetu/F1'SA/efsa locale 1178620753812 121190201 2410.1itm . 

Emmett, E.A. et al. 2006. Community exposure to perfluorooctanoate : Relationships between 

serum concentrations and exposure sources . J. Occup. Exp. Me :1 ., 48, 759-770 . 

Ohio EPA (2008) ( littL) :,',~www.ct)a .statc .oh uti/dswitisl1advisory/2008fishadvisory parnphlt,t pdf) 

Higgins, C. ; Luthy, R. 2007. Sorption of Perfluorinated Surfactants on Sediments. Environ, Sci. 

Technol . 40: 7251-7256. 

Scott, B.F. ; Spencer; Mabury, S.A. ; Muir, D.C.G. 2006. Poly and Perfluorinated Carboxylates in 

North American Precipitation . Environ. Sci . Technol. 40: 7167-7174. 

Stahl, T. et al . 2009. Carryover of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate 

(PFOS) from soil to plants . Arch. Environ. Contam. Toxicol. (in press, available online) . 

USEPA 1997. Exposure Factors Handbook. Washington, DC, Office of Research and 

Development, EPA/600/P-95/002 Fa,b,c. 

US Fish and Wildlife Service . 2004. 

Ihttp :%;`www.wvdiir .gov/lisliitig/PI)FJ`Files/Ohio River Management Plan Revised pdf 
Appendix A 

A.1 Summary of March 23-24,136J Public Meeting 

Pa.rkersbur;~. West Virginia 

Registered Attendees: 

ITP Administrator : 

Mitchell Small 

Peer Consultation Panel (PCP) members: 

Joel Baker; Kannan Kurunthachalam ; Linda Lee; Paul Lioy; Scott Mabury; Michael McLachlan; Rosalind 

Schoof; Thomas Watson ; 

DuPont and Consultants: 

David Boothe; Cathie Barton; Andrew Hartten; Kathy Davis (URS); Tim Bingham ; Steve Washburn (Environ) 

EPA: 

Cathy Fehrenbacher, Laurence Libelo, Deborah Sherer 

The public : 

Robert Griffin, Little Hocking Water Association ; Linda Aller, Bennett and Williams ; Tony Fletcher, London 

Schocl of Hygiene and ".'roaical Medicine (C-8 Science Panel) 

ITP assistants: 

Gloria Dadowski; Kan Shao 

Meeting called to order at 1:OOPM March 23, 2009, EDT. 

Welcome and Introduction 

by Dr. Mitchell Small 

DuPont and EPA are signatories to the MOU in which DuPont has committed to provide EPA with 

certain data and information on perfluorooctanoic acid and its salts (PFOA) through a PFOA Site Related 

Environmental Assessment Program for the Washington Works manufacturing plant and surrounding areas. 

This peer consultation is evaluating the scientific quality and completeness of studies conducted by 

DuPont and its consultants to characterize past and current releases associated with the site, and quantities 

of PFOA in nearby environmental media, including those media that can lead to human exposure . 

This data gathering has been conducted through phased activities, known as Phase I and Phase 11, to 

prepare the following reports: 

1 . Data Assessment : DuPont Washington Works, DuPont Corporate Remediation Group, October 2, 

2008. 
2. Screening Level Exposure Assessment for DuPont Washington Works Facility, Parkersburg, West 

Virginia, Environ, October 2, 2008. 

3. Future Data Needs Assessment : DuPont Washington Works, DuPont Corporate Remediation 

Group, October 2, 2008 . 

The specific charge question posed in the DuPont-EPA MOU is : 

"Are current PFOA environmental releases and sources of those environmental releases from the Site 

and the presence of PFOA in environmental media on and around the site sufficiently understood so that 

pathways of migration and exposure to PFOA associated with that Site are adequately characterized and 

assessed on a screening level basis?" 

The process for the PCP member selection was: 

a. Selected by ITP Administrator Mitchell Small following a public nomination procedure announced on 

website: http ://itp-pfoa.ce.cmu.edu/ (closed on August 22, 2008) 

b. 13 candidates nominated by US EPA (6), DuPont (3), Mitchell Small (3), Robert L. Griffin (1), and 

self (1) 

c. Members chosen based on the need to address particular topics in study and strength of scientific 

qualifications 

d. Committee includes members nominated by US EPA (4), DuPont (2), Mitchell Small (2), and Robert 

L. Griffin (1). 

In order to do the evaluation, we identified six major topic areas, principally by media and discipline . 

For each area : air, surface water and sediments, soil and groundwater, biota, multimedia, and human 

exposure; one or more panel members were assigned as major reviewers who have principle responsibility 

writing that section of the report . Minor (secondary) assignments were also made for each section. PCP 

member assignments are shown on the following page. 

For each section, one of the lead (major) panelists will report on the Panel's findings in the Preliminary 

Report. 

Overview of agenda today: 

" 1 :00 - 1 :10 Welcome and overview of peer consultation process 

" 1 :10 - 1 :20 Welcome by representative of US EPA 

" 1 :20 - 1 :30 Introduction to members of the PCP 

' 1 :30 - 2:10 Presentation by DuPont on scientific studies and reports 

" 2 :10 -2:40 Questions 

" 2 :40 - 5:25 Reports by PCP Members on Preliminary Report findings for each of six topic areas 

" 15 minute presentations 

" 10 minutes questions 

" 5:25 - 5 :40 Summary of discussions and plans for second day of meeting 
Surface 

Air water & 

Soil & 

Biota 

Multi- Human 

Panel Member groundwater Media Exposure sediment 

Joel Baker Minor Major 

Kannan 

Kurunthachalam 

Minor Major 

Linda S. Lee Major Minor 

Paul J . Lioy Minor Major 

Scott A. Mabury Minor Major Minor 

Michael 

McLachtan Minor Major 

Rosalind A. 

Schoof Minor Major 

Thomas B. 

Watson 

Major Minor 

Welcome and Introduction from EPA 

By Cathy Fehrenbacher 

Cathy Fehrenbacher expressed appreciation for the assistance from both Dr. Small and the Peer 

Consultation Panel because this is a very important agreement between the Agency and DuPont. She would 

like to encourage the Panel to pay close attention to the Charge . She also briefly summarized the process 

for the Phase III commitment. EPA is happy to answer any questions from the Panel, although EPA is 

primarily here to listen in the meeting. 

Self-introduction of PCP members 

Thomas B. Watson, Ph.D. 

Tracer Technology Group Leader 

Brookhaven National Laboratory 

Expertise: Atmospheric Tracer Technology and Applications; Atmospheric Transport, Diffusion and 

Dispersion ; Atmospheric Chemistry 

Scott A. Mabury, Ph.D. 

University of Toronto 

Department of Chemistry (Professor and Chair) 

Expertise: environmental fate, disposition, and persistence of chemical pollutants, particularly interested in 

the influence of fluorine . 
p. 69 

Paul J. Lioy, Ph.D. 

Environmental and Occupational 

Health Sciences Institute (EOHSI) 

UMDNJ - Robert Wood Johnson Medical School 

Exposure Science Division, Environmental and Occupational Health Sciences Institute 

Expertise: exposure and risk assessment . 

Rosalind A. Schoof, Ph.D., DABT 

Integral Consulting Corporation, Inc. 

Expertise: exposure assessment, particularly bioavailability and dietary intake of metals. 

Kannan Kurunthachalam, Ph.D. 

Research Scientist 

Wadsworth Center, New York State Department of Health & 

Professor, Department of Environmental Health and Toxicology 

State University of New York at Albany 

Expertise: understanding the environmental distribution and fate of organic pollutants . 

Michael McLachlan, Ph.D. 

Stockholm University 

Department of Applied Environmental Science (ITM) 

Deputy Head of Department 

Expertise: fate, bioaccumulation and persistence of organic chemicals 

Joel Baker, Ph.D. 

Professor 

Interdisciplinary Arts and Sciences 

University of Washington Tacoma 

Expertise: fate and transport of organic pollutants in environment 

Linda S. Lee, Ph.D. 

Purdue University 

Department of Agronomy 

Expertise: fate and transport of contaminants in the environment, primarily focusing on soil and witer. 

Welcome and introduction from DuPont 

By David Boothe : 

Mr. Boothe first expressed appreciation to Dr. Small, the PCP, and EPA. 

The DuPont team includes : David Boothe (Team Lead), Cathie Barton (Air Programs), Andrew Hart-1-

(Monitoring Program Lead), Kathy Davis (Data Analysis & Reporting), Tim Bingman (Exposure 

Assessment Lead) and Steve Washburn (Exposure Assessment Consultant, Environ) 

66 
Mr. Boothe briefly provided an overview of the MOU process, the history of this project and related 

information and studies for this study. 

Community studies/projects include the C-8 Science Panel ( www.c8sciencepanel.org ); Penn/Emmett 

Studies-Little Hocking Community and C-8 Health Project (see WVU School of Medicine Website). 

The emissions of PFOA from the Washington Works Site have been significantly reduced over the 

period 1999 to 2006. Some language needs to be clarified from the MOU, this study focus or the "current 

presence of PFOA in environmental media". Further, the MOU also allows quantitative, semi-quantitative 

and qualitative data to be used in the study for the description of exposure. EPA Guidelines were used for 

exposure assessments and the Screening Level Exposure Assessment (SLEA) is step 1 in a phased 

approach to focus future work on potentially significant pathways . 

Andrew Hartten: 

Mr. Hartten gave a brief update about the sites studied, a quick overview of the sampling program, the 

analytical program, and how the data were translated and interpreted for use in the SLEA. 

Four sites covered by the Data Assessment Report include the DuPont Washington Works Site and three 

landfills: the Letart Landfill, Dry Run Landfill, and the Local Landfill . These sites were briefly reviewed . 

The scope of the multimedia sampling program includes : ambient air and rainfall, water and subsurface 

soil (residential water supplies ; public water supplies ; Ohio River water; subsurface soil and groundwater at 

the LHWA; site and landfill surface water and groundwater), surface soil and grass; small mammals and 

fish . Thousands of samples were collected and analyzed from these media. 

A number of scientists analyzed the collected data and new methods development was implemented for 

some of the media, including air, soil, grass and biota as part of the MOU work. All measurement results 

(100%) were reviewed by participating laboratories and internally by DuPont, while 10% of the data were 

reviewed by a third party. 

The sources of PFOA releases were identified : air emissions and permitted outfall emissions; on-site 

SWMUs; landfilled materials; single point releases. The presence of PFOA in environmental media was 

evaluated: multi-media sampling; in general, air, rainfall, soil, and groundwater show decreasing PFOA 

with distance from the Site . The pathways of migration are understood : air emissions on-site to on-and offsite environmental media; permitted outfall emissions on-site to the Ohio River and to off-site 

environmental media; landfills via groundwater flow and leachate . Sufficient understanding and data to 

conduct the SLEA and relevant spatial and temporal data analyses were carried forward for use in the 

SLEA. 

Tim Bingman: 

Mr. Bingman introduced the general background and information about the Screening Level Exposure 

Assessment. 

The purpose of the SLEA is to characterize current human exposures and the potential for future 

exposures in the vicinity of the Washington Works Site and associated landfills, based on available data . 

The general scope of the assessment was defined by the Memorandum of Understanding: quantitative 

assessment of any exposure pathway for which data are available; qualitative or semi-quantitative 

assessment for pathways where data are not available to permit quantitative evaluation . The USEPA 

guidelines for exposure assessment, 1992, as specified in the MOU and various other relevant guidelines on 

67 
p. 71 

exposure assessment and risk characterization from USEPA, 1989-2006, provided the relevant guidance for 

the SLEA. 

There were five main steps in the SLEA process: 

(1) Conceptual Exposure Model Development: 

Identify the: Chemical sources; Transport routes ; Exposure points ; and the Human 

exposure routes 

(2) Exposure Area Identification : 

Identified public service districts for drinking water; evaluated data from private 

drinking water sources; evaluated other data from other media 

(3) Exposure Point Concentration (EPC) Calculation: 

Used data from the Data Assessment Report; encompassed data from the relevant 

time period ; calculated EPCs, RMEs (reasonable maximum exposures) and MTEs (more typical 

exposures) for all relevant media 

(4) Potential Exposure Estimate Calculation: 

Integrated EPCs with human activity patterns and physiological characteristics; 

calculated RME and MTE exposure estimates for both adu'_ts and children 

(5) Uncertainty Evaluation : 

Described potential uncertainties in exposure estimates for pathways with 

monitoring data ; modeled exposure contributions for pathways lacking data ; 

identified potential data gaps for further consideration 

General findings of the SLEA are: 

-Calculations based on monitoring data indicate that ingestion of untreated drinking water was the 

primary exposure pathway 

-Intakes from drinking water ingestion are expected to decrease as a result of decreases in drir.king water 

concentrations resulting from mitigation and remediation measures 

-In specific limited subpopulations of farmers and gardeners, screening-level modeling indicates that 

exposure from consumption of locally-grown crops and locally-produced milk could be similar in 

magnitude to intakes from drinking water 

Question session: 

Dr. Kurunthachalam : 

Are soil samples from local farms available in the Reports? Did these reports consider that irrigation waters 

from the Ohio River could contaminate the farmland soil? 

Andrew Hartten: 

Some data might be in the multimedia data report . The area just shown in the Data Assessment Report is 

the sampling location for soil, there are a lot of areas that are farms, but the access to residential properties 

needs to be negotiated. The soil concentration in the SLEA was added to an additional concentration from 

irrigation. 

Dr. Baker: 

Was the role of flooding and transport of fine sediment to the surrounding area taken into accoun~ ?n tL .e 

conceptual model? 

68 
p. 72 

Andrew Hartten: 

It is not largely considered . What is considered is that the data collected in the investigation did include 

areas that were historically subject to flooding . In addition, there were some flood situations represented in 

the datasets, such as 2004 and 2005 . Conclusions can be drawn by the PCP based on these available data. 

Dr. Baker: 

In Figure 4.1 which summarizes about water and air emissions between 1999 and 2006, what data have 

been shown? Which locations are included or summed to obtain the emissions in each year? How many 

data points or estimates are used for each year? 

David Boothe: 

Obviously, we don't have continuous online monitors at outfalls for PFOA. So, we did some combination 

of sampling from both water streams and air streams, along with using the operations systems data for the 

work site . Therefore, this is a result from sampling data and reported operating conditions from time to 

time . These emissions are from our manufacturing operations. 

Dr. Lee: 

Were any of the wastes from the work site land applied? 

David Boothe : 

Sludge materials from the water treatment process were land applied in landfills prior to the 90's. 

Dr. Mabury: 

Was there any other disposal activities on-site, such as a deep injection well? 

David Boothe: 

Specifically, with respect to deep injection wells, there was no injection of any of these types of wastes. 

Dr. McLac!ilan: 

The idea of Tim's presentation is to present information and gather information on current and potential for 

future exposures. However, what was presented is for the past . Would you say that the potential pathways 

for the future are also well addressed? Is this understanding correct? 

Tim Bingman: 

The word "current" is applied to the initial phase of this assessment when the contract of the MOU was 

activated in 2004. The MOU goes on to say that after the Phase III data collection, there will be a 

subsequent edition of this document that will in fact define the future state in contrast to the state at the 

time of MOU signature. 

Dr. Small: 

In the on-going detailed exposure health studies that were mentioned in the community, is anyone working 

on the indoor environment, in particular dust as a source of FFOA or related compounds? Also, are any of 

them are taking samples of breast milk? 

69 
p. 73 

David Boothe: 

We don't know detail information about these independent studies at this point. They have all the 

information about this study, and they deliver findings through publications. 

Dr. Small : 

Is anyone considering an isotopic study as a part of the hydrogeological evaluation to find out different 

sources of water in the aquifers? 

David Boothe: 

No. No one is trjing to conduct an isotopic study. 

Rpports by PCP Members on Preliminary Report findings 

Air monitoring and dispersion modeling 

by D:. Thomas Watson 

There were some important findings in two major topic areas: 

1 . Air Monitoring: 

The airborne PFOA sources are insufficiently characterized. There was no attempt made to verify le 

production factors from direct emissions measurements during either of the air monitoring phases. There 

should be further explanation of the measurements that were used to determine these formulas and data on 

the validation of these calculations with actual stack monitoring . 

The temporal and spatial resolution of the air monitoring was insufficient to characterize the transport 

and dispersion of PFOA in the areas likely to be affected by emissions. There is no discussion of the 

seasonality of atmospheric concentration levels. The behavior of PFOA in the environment is hkely to be 

temperature dependent and therefore both diurnal and seasonal . It is also possible that there may be daily or 

seasonal cycles of surface deposition and reemission to the atmosphere of PFOA, particularly in the 

summer. Monitoring should be conducted in the winter and summer so the dependence of atmospheric 

concentration on seasonal temperature extremes can be characterized. Air monitoring with diurnal time 

resolution is also necessary to capture temperature dependent deposition and re-suspension cycles . 

Atmospheric transport and deposition cannot be accurately assessed, or the effects of the site delineated, 

without extending the study domain until the measured PFOA concentrations are at or near a~mospheric 

background levels . 

2 . Mass Balance: 

Mass balance calculations need to be done at many levels . 

A mass balance should be checked at the 2-mile radius domain level. 

There was no air sample collected at a height greater than 3.6 meters above the surface. Measurements in 

the vertical dimension are necessary to fully characterize the PFOA transport regime and provide data :or 

model validation . 

70 
Air monitoring with diurnal time resolution is necessary for capturing the pattern of temperaturedependent deposition. Monitoring also should be conducted in winter and summer so that seasonal 

temperature extremes can be characterized. 

Surface water and Sediment 

by Dr. Scott Mabury 

Based on the basic information provided in the reports, it is clear that PFOA was transported at least 50 

miles from the Washington Works Site, and likely further given PWS contamination, though no surface 

water samples are reported further downstream than Racine. The lack of assessment of the extent of PFOA 

migration and exposure to downstream locations is a major omission in this report . 

Ohio River Monitoring was carried out in the summer and fall of 2002 with specific dates of sampling 

June 27, July 10, and October 17 . No information was provided that outlined the rationale for selection of 

sample day, location, or why the sampling was spread out over five months. 

Overall, there were 68 samples included in the SLEA (Transects 1 to 12 from 2002 and 04/05 samples 

near outfall 005), of which 39 were ND or NQ for PFOA. In summary, river water sampling was so 

intermittent, and lacking in information regarding time of day or week, plant operation, river flow etc, that 

it is difficult to have a sense of what the river water concentrations mean. 

Sediment samples were not collected from any of the water bodies in or around the Site although there is 

a potential that runoff from several contaminated sites including the solid waste management units 

(SWMU) can result in the migration of PFOA. There is a need for monitoring of sediments from the Ohio 

River near the outfall, upstream and downstream of the Site, and the three landfill areas to assess the 

migration of PFOA through sediment transport. 

Soil and Groundwater 

by Dr. Linda Lee 

Based on the information provided in the USGS report, some concerns about whether there are some 

hydrological connections underneath the river to the Little Hawking site are much diminished. The 

hydrological analysis that had been done is reasonable and acceptable . 

At LHWA, soil concentrations support the inference that much of the PFOA present is likely from wet 

deposition followed by percolation into the groundwater. Given that emissions are still occurring (although 

to a much lesser extent) and the variable nature of weather-dependent wet and dry deposition, having 

variable concentrations in the soil and subsurface profile is really not surprising. However, the extent to 

which air emissions of PFOA contamination have contributed to the groundwater contamination is not 

clear. No mass balance was done to see whether this route could yield such extensive and high PFOA 

concentrations in groundwater. 

While air emissions by 2006 have dropped two orders of magnitude compared to 2000, the 2006 

sampling and analysis of plants near the facility show substantial PFOA concentrations on plant surfaces of 

which much of this mass was clearly from surface deposition and free to mobilize to the soil surface anc: 

percolate to the aquifer. 

71 
Further, the observation that "residences that are located downwind of the Site have higher 

concentrations of PFOA than do residences upwind of the Site" would support the predominance of the airsoil-groundwater pathway; however, as previously noted, the results shown in Figure 5.7 of the Data 

Assessment report are not consistent with this statement. 

Biota 

by Dr. Kannan Kurunthachalam 

There are several possible pathways for exposure to PFOA including: Air-Produce-Consumers; WaterFish-Anglers; Air/Water-Soil-Farm Produce-Consumers; Local produce-consumers/infants; Air/waterGrass-game animals-hunters. 

Fillet of twenty fish (largemouth bass and channel catfish) were collected near outfalls in Oct 2005, 

while twenty reference fish samples were collected upstream for comparison. Grass samples were collected 

on-site in the 2 mile radius . Small mammal (meadow vole) plasma/liver samples were collected from the 

Little Hocking Water Association site and all results were ND. 

Fillet from the twenty fish collected in October 2005 were analyzed and a more typical exposure (MTE) 

concentration of 1 .4 ng/g and reasonable maximum exposure (RME) concentration of 2.7 ng/g have been 

derived for exposure assessment in anglers. 

The MTE and RME from two fish species, ten for each, from onsite is not representative of the exposure 

distribution that could be present in the site area . More species from multiple locations along the river and 

other surface waters are needed for representative exposure concentrations in fish. 

The report mentions that fish may not contribute to significant PFOA exposure (relative to drinking 

water) near landfills. The current exposure model suggests that the exposure rate from fish consumption is 

2-4 fold lower than that from drinking water (for the Letart landfill). Therefore, the problems include: 

First, no fish were collected from landfill area water bodies . Second, fish data used in the model are not 

representative . Third, based on bioaccumulation factors in the literature, 10-fold higher PFOA levels than 

what were measured in two species are typical. This would result in 10-fold higher exposures than what 

was modeled. Fish ingestion rates used for anglers are also low. It is important to separate subsistence 

fishing and recreational fishing. EPA's exposure factor handbook suggests fish ingestion values of up to 

170 g/day. 

Hunting has also been identified as a possible exposure pathway. Potential PFOA exposure can occur 

through the consumption of game meat through food chain transfer but no game animals have been 

analyzed. Analysis of game such as deer, turkey, duck, rabbit, pheasant, quail and home-raised poultry is 

needed if this pathway is to be evaluated for its significance. 

Mean serum PFOA levels in an affected population are typically 100 fold higher than the US general 

population mean value (-400 versus 4 ng/mL). Blood and breast milk PFOA concentrations are positively 

correlated . There is a potential for local area infants to be exposed to high levels of PFOA through breast 

milk consumption. Infant exposure needs to be assessed (this is a sensitive subpopulation; breast milk 

monitoring is needed). 
p. 76 

Multimedia Fate, Transport, and Exposure Pathways 

by Dr. Michael McLachlan and Dr. Joel Baker 

The criteria for a screening level assessment should include: identifying major pathways of migration; 

basic understanding of the governing processes; semi-quantitative description of mass flows along the 

major pathways ; and a basic level of field validation of the above. 

Indentifying pathways has been done reasonably and a plausible site conceptual model is presented. One 

pathway that was not considered is downstream users and consumers of Ohio River water. 

The first process is atmospheric deposition, which was modeled with AERMOD and measured in 

surface soil and vegetation . The results were consistent, suggesting basic understanding. 

The second process is surface to groundwater. There are some contradictory statements in the 

documents, e.g . section 6.1 .4 vs . sections 4.3 and 5.2 .4, so basic understanding is apparently insufficient. 

For the pathway of surface water to food, there were also some contradictions between models and 

measurements and knowledge. Proper measurements are needed . 

Overall, the big picture is missing: a multimedia mass balance is needed; this should consider available 

information on chemical mass flow and chemical mass inventory; should incorporate available process 

understanding; should address changes in the past and prospects for the future ; and should provide 

exposure source allocation vs . time . Further, it should include the use of downstream river monitoring and 

Washington works emissions monitoring to estimate the contribution of other sources to the river and to 

assess downstream exposure. 

Further data are needed to verify the conceptual model: (1) Resample local vegetation and soils with 

sufficient density to verify reduced atmospheric deposition loadings from emission controls ; (2) Enhanced 

sampling around landfills to better understand exposure pathways and to document efficacy of controls ; 

(3)Transfer from groundwater to food, especially near riverbanks downstream of facility; (4) Extend multimedia calculations (especially air-soil-vegetation-groundwater) downstream to include all areas with 

elevated PFOA in groundwater. 

Human Exposure 

by Dr. Paul Lioy and Dr. Rosalind Schoof 

The preliminary assessment should be recast in terms of some benchmarks made in this meeting, taking 

into consideration, what will be the major pathways of possible exposure and where are the populations at 

risk'? 

The Charge required the PCP to determine whether all the data gaps that need to be filled have been 

identified in the report. What the PCP is trying to do is to answer the following question: as the SLEA is 

currently presented, is it adequate for the PCP to actually make the determination whether all the data gups 

have been identified? At the very beginning of the report, there is a failure to explain to the reader the scope 

and limitations of the SLEA study and report . 

Another major comment is : uncertainty analysis should be done for each pathway, and that will facilitate 

the review of the PCP. Except for drinking water, which has a reliable database for estimating local 

exposure at all three locations, most of the data and estimates are presented as part of ar. uncertainty 

73 
analysis . While an uncertainty analysis is certainly appropriate, it must first be preceded by a thorough 

documentation of what was done to obtain as much local data as possible, and how these data were used to 

obtain best estimates for the targeted exposures. Unfortunately, there is little or no local data that was 

collected or used to serve as a basis for many of the exposure route estimates completed for each location . 

Day-One Meeting adjourned at 5:30PM. 

Day-Two Meeting started at 8:45AM, March 24, 2009 

Dr. Small briefly introduced the agenda for this meeting. 

Explanation of Memorandum. of Understanding (MOU) 

by Cathy Fehrenbacher 

Some terms needs to be clarified. 

"Exposure to PFOA Associated With The Site," as used in the Charge, refers to current exposures and 

the potential for future exposures from the presence of PFOA in Environmental Media as a result of 

Current or Past Manufacturing Activities at the site, but does not include an assessment of exposures that 

may have occurred in the past . 

"Associated with The Site," as used in the Charge, includes any current environmental release or 

presence in Environmental Media of PFOA on and off the site resulting from Current or Past 

Manufacturing Activities at the site . "Current or Past Manufacturing Activities" at the site refers to all 

activities that may have resulted in the current presence of PFOA in environmental media both on and off 

the site without regard to distance from the site, including but not limited to waste disposal activities that 

occurred off-site, such as landfills that received materials from the site ; land application materials 

originating from the site ; off-site treatment facilities receiving waste material from the site ; and air 

emissions that may have deposited off the site, except that "Current or Past Manufacturing Activities" does 

not encompass commercial products manufactured at the site and distributed in commerce . 

"Environmental media," as used in the Charge, refers to air, surface water, groundwater, soil, aediment, 

biota, wastewater, waste streams, landfills, landfarms, water discharges and offsite disposal of all types. 

More detailed explanation of other terms also can be found in the MOU. 

Summary of Report Plans by Section 

Human Exposure 

by Dr. Schoof, Dr. Lioy 

Dr. Schoof: 

At this stage, more uncertainty analysis, not collecting more data, in the SLEA might make the report 

more sufficient for the PCP to judge if the data gaps have been filled . 

Dr. Lioy: 

74 
p. 78 

More data, especially site-specific data are needed to improve the Screening Level Exposure Assessment 

(SLEA). Comment for the next round is that : analysis should be done from the back end going forward, for 

example, more data about bio-accumulation should be collected. 

Question from Dr. Small: 

Should we discuss how the on-going health exposure studies in the community interface with our study? 

Dr. Lioy: 

Yes. More data are always better . 

Biota 

by Dr. Kurunthachalam 

There are insufficient data for the biological media available; only <2% of the total samples are 

biological despite the fact that biota can be an important pathway for human exposure to PFOA. More data 

reed to be collected for biota. Some of the sub-populations are not addressed properly, such as infants. 

Breast milk monitoring in the local population is needed to assess PFOA exposure in infants 

Question from Dr. Small: 

In terms of prioritization, what are the three most important biological media? 

Dr. Kurunthachalam : 

It is believed that some biota may not provide an important pathway for PFOA exposure in humans. Since 

biota encompass a wide variety of samples (plants, farm products, animals, fish, milk, etc) it will be helpful 

to analyze a few samples for those biota samples that are believed not to present a major pathway; this will 

enable elimination of those biota species as a pathway of exposure. For example, game animals are 

assumed to be an insignificant route of PFOA exposure (considering the lesser bioaccumulation potential of 

PFOA). However, it is not possible to rule out this as a possible route of exposure without some 

preliminary data . Overall, it would be effective to identify pathways that are of least significance (based 

on the knowledge of PFOA bioaccumulation and proximity to sources), provide some data for those media 

to support the hypothesis and eliminate that as a pathway from SLEA consideration. Efforts should be 

made for different species of fish to assess exposures in anglers. The process should be implemented step 

by step for effective and efficient use of resources. 

Multimedia 

by Dr. McLachlan and Dr. Baker 

This summary is allied with the yesterday's discussion . The transfer of PFOA following air emissions to 

surface soil was studied and reported and this work is considered sufficient for a screening level 

assessment. Although information on PFOA emissions to the Ohio River as well as PFOA concentrations 

in the Ohio River is available, no effort was made to assess whether this information was internally 

consistent . No empirical evidence was identified to support the understanding on PFOA transport from 

75 
p. 79 

surface soil to groundwater and no measurements have been done on pathways leading to food. This is 

appropriately identified as a future data need in the reports. 

Question from Dr. Small: 

Is a multimedia modeling framework available that can handle chemicals with properties similar to 

PFOA? What is the best way to do the mass balance in a multimedia model? 

Dr. McLachlan: 

A model to handle this problem is available. But some data collection and preparation needs to be done 

before using this model because some components in the model are really barriers . And this is a multimedia 

model, not attacking one medium at a time. 

Soil and groundwater 

by Dr. Lee 

Additional data associated with potential contamination of groundwater and migration to offf site streams 

from the ponds and contaminated layers in or near the water-bearing zones under the former landfills are 

warranted as well as some post monitoring of the Riverbank Landfill and Anaerobic Digestion ponds that 

will have an engineered cap system . Additional assessment as to whether or not pumping at LHWA is 

causing some unexpected hydraulic connection between the water underlying the Anaerobic Digestion 

ponds is suggested as well. Further details are provided below for the Washington Works Site, the LWHA 

site, and the Local, Dry Run, and Letart Landfills. 

Question from Dr. Small: 

Is there anything isotopic that can be done to illuminate what water is coming from where? 

Dr. Lee: 

First, getting some sediment samples could offer a lot of insights . From there, whether an isotopic 

analysis would be needed and beneficial can be determined. 

Surface water and sediment 

Dr. Mabury 

Additional sampling was carried out at two dates in each of 2004 and 2005, in the Ohio River at and near 

the Outfa11005; for reasons unknown the outfall itself was not apparently sampled on those days. Near the 

outfall, i .e . 5 ft to 20 ft from the bank, PFOA concentrations were generally between 1 and 6 ppb with 

concentrations dissipating out to "300 ft from the bank". It is unknown what the specific transect, relative 

to the outfall, was sampled in the river. 

Overall, there were 68 samples included in the SLEA, of which 39 were ND or NQ for PFOA. In 

summary, river water sampling was so intermittent, and lacking in information regarding time of day or 

week, plant operation, river flow etc, that it is difficult to have a sense of what the river water 

concentrations mean. 
Furthermore, sediment analysis is important for the assessment of pathways of migration of PFOA from 

the site and the landfills. Sediments are also important pathways of exposure to fish and benthic organisms. 

Human exposure to sediment can occur as a result of incidental ingestion and dermal absorption . 

Question from Dr. Small: 

There are a number of measurements that could be made for compounds that are related to PFOA. Can 

these measurements be used to make inferences about local PFOA vs . global PFOA, and short-term PFOA 

vs . long-term PFOA, in the site areas? 

Dr. Mabury: 

It is more difficult in this situation; one cannot simply make such an inference. Nonetheless, methods 

development is underway for this type of evaluation, and for related compounds that can readily be 

analyzed, such analysis should be made. 

Air 

Dr. Watson: 

The mass balance calculation is extremely important. The monitoring and modeling cannot be assessed 

if there is not some attempt to see if all the released material can be accounted for in the environment. 

Modeled and measured mass balance calculations are necessary to account for all emissions and validate 

the monitoring, modeling, and exposure assessments. 

Air monitoring with diurnal time resolution is necessary to determine daily temperature dependent 

deposition and detect deposition and re-suspension cycles . Winter and summer air sampling is necessary to 

determine the temperature dependence of deposition and transport processes. 

Wrap up 

by Dr. Small 

Following further discussion and public input at this meeting, the report will be modified, eventually 

leading to a Final Report of the PCP (anticipated posting on web site for final public comment by May 15, 

2009, with final report submitted to US EPA by July 10, 2009). 

Thank you all for participating! 

Meeting Adjourned, 11 AM 
A.2 Public Comments 

The following public comments were received during the course of the Peer Consultation 

Panel review : 

1 . Comments of Robert L. Griffin, General Manager, Little Hocking Water Association, 

Inc., submitted March 30, 2009. 

2. Comments of Robert L. Griffin, General Manager, Little Hocking Water Association, 

Inc., submitted June 30, 2009. 
1 . Comments of Robert L. Griffin, General Manager, Little Hocking Water Association, 

Inc., submitted March 30, 2009. 

March )iJi. 2009 

LITTLE HOCKING WATER 

ASSOCIATION, O'ASSOCIATION, IN" 

194A 51 q9 1?d " P d~ Ron 188 " LAN,- Hoi:kirn;t . OH 

~Y~tizt:,8it+," iVWwY,li3l~~ds£wt:~G(t"td~W'c71+~r ~fitiJ . . . 

DuPont-EPA P1"OA Peter Consultation Panct 

c,"'o FN Mitctrcll Small, independent Third Party Adrninistnltor 

C?epartmerix or( ."evil & Environmental Engineering 

Porter 11a)1 119, Fre+w Street 

G'araaegir~ Mellon University 

Pittsburgh, PA t S213 

Re Comments on March 16, 200±3 Preliminary RepRart ofthe Peer Consultation Panel 

Dow [,)it Small : 

On behalf of the Little i locking Water Association ("`L.HW A")* 1 am writ 

comments an the Peer Consultation Panel's (-PCP-') March 16, 2009 PPrelimi nary 

eix"A ) . 

We greatly appreciate the PCF'"s efforts and insight, During the cour-W oftheil review 

'.P panelists discovered significant limitations and omissions in the data cottraceed unri 

analyses presented. We share the sentiments cfithe PCP. We also share the o0nion 

the PCP ( as stated in the- Report's -Summary of Key Preliminary Findings Wid 

Conclusions") that a significantly expanded data collection and analysis progymm is 

required, With this in mind, these camtnwts. 

I ) provide facts relevant to the Report's concluMael that drinking Vvt"T is not 

"currently" (i rc "at this mcxrrwn :"1 tie dominant exposure pKtlway; 

2) support aeW provide facts relevant to the Report's recommendation that MPont 

needs to expAnd its future data ccrllectirin cfForts by testing for eathw fluarinatref 

chemicals, in addition to PF10A; 

support the sampling recommendations offered by the PCP that Will rill data saps. 

4) provide sunestions with respect to DuPont's groundwater flow rrradel ; and. 

5) provide information about apimefta disposal sit+es not addrimmii in the Repot. 

which may foster insights into the sources oftlfe PFOA contamination. 

[,F i'IIu''A' ;t comments cover the Major issues noted in Our review Of the Rep+art au'ttt are not 

intended to be a comprehensive critique of the Repcirt . 
thinking water as the dominant crpo=re pathway 

We believe that drinking water remains the pateni-ially dominant exPvs= Pathway 

despite the current granular activated carbon filtration ("fiAC") of LHWA'S vrttW prior 

to use When discussing the relative importance of dMerent exposure pathways, the 

Il:epcut states that "(t]he conclusion that drinking water is the dominant exposure pathway 

is particularly problematic and could be misleading, because that is currently rot the 

case'" This opinion, while auffemly accurate for LEiWA, appears to be oversimplified in 

that, 

a. there is a significant threat that DuPont will try to discontinue the C'sAC.' filtration 

a settlement agreement reached in the West Virginia class action lawsuit, 

I.~.aac Jt. e i at k~ E:1. Lutjurrt ik Nem~s and ( . ."ompany: 

tr Because of the high PFOA levels in the blood of many L14WA members, them, 

are scientific and medical uncenainties connected with drinking w*er with my 

PFOA ! ¬1 it, 

other pertlu+arirratet! chemicals, such as PFB A (C4), ppM 1hrougb GAC syatetrm 

and, 

filtration does not remove alt perfluorirutted chemicals. We understand that 

d . Despite tests showing that the GAC plant is producing finished water that is nondetect for pF+DA, detectable levels of PFOA were found in various pens of 

UMA"a distribution system after GAC ttpetmions bqpn. LHWA and other 

water systems need to be checked to veriA~ " PFOA and related chemicals are 

,not detected in these systerns, 

Textingfor other pdrrearinated rkentirols 

In &Mtiun to p'FOA, samples taken by LHWA have confirmed the presence of 

other perftuorinatcd chemicals in LFiWA's urelttie.ld and in the Mood of LMWA 

mHcazabcrs The chemicals detected include higher chain chemicals(cg_, G9. CI O, and 

), which we understand to be even more dangeTam to !unign health than RFOA. As 

noted ab¬~-ve, despite LHW A's turgin$ in recent yeara, EU00"t taS " MadC a 

commitment to make sure other pct-fluorinated chemicals are being removed by the GA.C 

plant LNWA strongly supports the Report's recomrrendatiort in Section 117 that future 

anaivsa be expanded to include other analytes. We find the Reports +eomatent that other 

relevant chemicals could have been '"co-analyzod at no cast or additional ~'to be 

accurate and in sharp contrast to [1up'ant's histcnic statements that tests could rot 

accurately distinguish between perflu+arionted chemicals. 
Data gVS 

"1'o the greatest extent possible, we request that the KP formulate specific action items to 

address data gaps and dericiencies found within the reviewed documents and to be 

included in the Phase III work items This will assist both the U.5_ EPA and DuPont in 

knowing the intended swpe nttd breadth of the necessary data and analyses- A review of 

the IvlflU reports underscores and amplifies the discussWcs at the recent PC:`P nrreding -

tut"rc data reeds relating to PFOA migration to the LNVw"A wellfteld inic,lude: 

9) MM!lMf.ll~

. 

inti in the Ohio River, includin& as suggested 

by a PCP member, a tritn3ect hum the LHWA well field to the location 

of the foTtLer AnScrCdblC Digestion Ponds (ADP) on the DuPont 

Washington Works fttlity (As was rnenticmed during the PCP 

delibermaans, the coarser fraction, of sedinients is not anticipated to 

contain higher coc4mratiana of PFt)A due to tire eharwer of the 

contaminant Therefore, the samples would be coCleded primarily 

from only the Irtner-grained portion of the sediments.)-, 

bj OwnIt1ifLf+`f'T1 .~L.a iiOap.+.'':am Sam 

field (and other appropriate lxmuons) to letter define tl<ae air and 

dk"ttton pathway-, 

0 r.&dlloction Of Ohio Ri~;~r v~- ~Moft both downstream or major 

cutfatls tend in the vieinirty of the LHWA well field (collected within a 

scientihcallv defensible time period and desigroW to evaluate 

concentrations and migration in a complex river setting that is 

controlled by locks and darns) . It isour understanding that the PCP 

wanted to take into account the elffects of barge ftWic, flooding, wind 

direction, and -pool effimta" an river flow, 

d) w1.lection of sarnP.~SAM hh"AXAM, AALM-Of theaauif~r 

that one PCP member postulated was the aubsurfiue source of PFOA 

in the Little Hocking Water Association and the Washin" Works 

Plant ; 

e) Co1loctaon of n 

order to c"lustc historic concentrations (prior to DuPont manufacture 

of PFOtl) versus recent an! curr+ent transport sM deposition (past 3M 

stoppage of PF~"1A manufacture} : 

Mon (Of, 

mwiwdu& in order to define and evaluate the effects on PF 

emissions reductiorts from the Washington Works plant, wtakh would 

logically also include sampling ftom groundwater to evaluate kwhing 

and concomitant reductions of PFQA in monitoring wells in the 

aquifer. 
) Der'fotnanre of mass baJ&noe to more closely align emissions 

and presence in environmental media, 

h) QcEf=ame +af a wafm infiltration mud+w in the LIiWA +amt! 

field to quantify mrawemert of water through sinface soils, 

movement c(PFtlA through the soils with the inflitrration ancl to 

further quantify the time for P'FfJA t4 be flushed *cm the 

unsaturated zone through the aquifer. (TWs could be used to 

further refitne the estimate preunt,dd at the PCP meeting of seven 

months to remove one-half the PFOA concentration from the first 

2 5 cm of surface soil - to see if the PFOA levels seen in the 

groundwater are supported by the dtposkion rate - and to estimate 

PF(3A removal rates from the well field), 

from the bedrock hills surrounding the alluvial aquifer may be an 

performance of an assearnem of the contribution of PFOA 

in which the LHWA 

field is lmted This awssmett sWul+d cecooze that no*N 

source of contribution of PFt3A to both the aquifer and, 

ultimately, the Ohio River, ad 

1) adentifi~atican a nd .. mpl of Imcntial M zonu a1ort tb~ 

Riverbank L.vcICill Samples of soils in identifiable seepage Zones 

of just above the Ohio River level would be collected and analyzed 

to assess potential migration of PFOA from the Riverbank Landfill 

to tire Ohio River 

As noted in the Preliminary Report and discussed during the PCP del 

source(s) of the PFOA in the GffWA well field are not i'iffly understood. The LHWA 

supports the objectives of the PCP to gather further dam to understand parbwaysof 

igration of PFOA and related chemicals. 

firm+rdivwer rrrWdi#g 

In its diwussaoras the PCP retognizei that modeling is are methodology useful in 

evaluating contaminant fate and transport in the enMiro+nment . However, the PCP also 

r tzed that modeling must be validated and results verified in orda to be 

scientifically defensible, Far example, the PCP reco,niczecl the need to collect 

specifically designed and distributed samples to provide necessary validation of the sit 

model Similarly, we rmcmmenW +itrat the PCP employ comprehensive validation crittris 

for the groundwater model, 

Sucb validation will require the collection of additional data, including aquifer infiltration 

data to quantify the amount of recharge to the well field from the Ohio River and to 
furxthcr calibrate the groundwater flow model. Such a study will require a sufficient 

rumbeT of wells an the bank of the river (including a new pumping well) and a stilling 

well in the Ohio Rivcr, The study would require water level measurements on both Sad" 

of the Ohio River to determine drawrdovun. Purnping conditions (both sides of the Ohio 

River) should be verified and as constant as possible. Test hales should be instal[led into 

the aquilrt under the Ohio River to evaluate stntigrapitic variations (or lack thereof) of 

the deposits and to evaluate whether there is dewatering under the river W, These 

vudies should be used to perform validation on the presence and position of the groundwater flow divide under the Ohio River that was postulated in the groundwater How 

model 

Howewet, modeling cannot replace a more complete undemanding of subsurface 

and xKuws of contamination, 

DuPont Is rtndag"nl' ik)ecifim we& and offs+ite diispoami skox 

In an effort to be comprehensive in identification of sourcea and path"ys,we ask 'lhM 

the PC P request that the fcAlawing potential sources of F`FOA be evaluated md eitlW 

eliminated oT addressed in the reports submitted under the h4C)tLl: 

wcL[LaAbc''Ashi gan Warks P'tuaL Public records, 

injection wells were used by DuPont for liquid, waste 

t them wells are no longer in service. Considering that trubsurfuce 

pow a potential grvuurd-wstet contamination wW migration 

pathway not atkdress+ed in the reports,, at a minimum the rtpart should dimuss the 

potential socarce, types and volumes of waste disposed, injection pressures, depth 

of well and completioWoperational information that may have resulted in 

overprcssurizatiocr acW,nr well integrity concerns for shallow migration . and, 

91tk -1Dbp. . k3&. For +emtrpln, we 

understand that a facility now known as the Little Hocking Service Center 

accepted extruder dies (cmtsircing PFOA) from the DuPont wowfacturing 

facility M Citclrvitle Ohio for incirreraticm This fircility is reportedly a DuPont 

peratiran and is located approximately one mile west of the LHW'A wefl field At 

a minimum. sir emissions, should be evaluated ftn 1113 facility A 

comprehensive survey of such facilities nee& to be completed, 

looking forward to the collection, submission, and analysis of the data 

collected, as well as, the independent review that the PCP is now urt+clat'tSkiryg . 

first E-nf'orceablt Consent Agreement ("EGA") public Meeting in WashinOw 0.C;. 

in June of 2003, L1`1WA submitted comments aM asked tbc IJ .5 . EPA, "Pleasie give us 

data and information that we tan have cc nfidence i-n " The LHWA actively paFticip4ut0l 

in tie ECA process until the Memorandum of 1.1nd+rarstanriing ("MW) was signed by 

DuPont and the U.S- EPA in November 2005, Since that time we have closely Mowed 

the MOtllrrocess . We appreciate the PCP's independent evaluation of the data contained 
i n the c"rts e+cl in the MOU and are happy to provide any asiditioruLl iaFormati 

that the PCP may need, 

srnccirclya 

LI`l"1`LE HOCKING WATFR ASSOCIATION, INC 

Rckct I . . Girifiin . P .E. 

General Manager 
2. Comments of Robert L. Griffin, General Manager, Little Hocking Water Association, 

Inc., submitted June 30, 2009. 

June .t(5, 2ttiYJ 

LITTLE HOCKING WATER 

ASSOCIATION, INC. 

'T ;a R1 '24 " r' (J Bar: " 98 - Lfte Hcri.kinq 041 457,12 

7~1,'~'3 'dR9 .??8l FAx 04()= 4e4- .554,1 

'rVphstle v:%tiVr t~l~lefi!+~,km!~w~.er t,ta 

OuP+aret-CPA PFUA Peer Consultation Panel 

cio 6)r. Mitchell Small. Independent Third Party Administrator 

Department of Civil & Fnvironmentai Engineering 

Porter Hall 119, Frew Street 

Carvnegie Mellon University 

Pittsburgh, PA 

Re Comments on June 4, 2009 Draft Final Rspot of thc 1°tasr Consultation Panel 

Dear Dr, Small 

f )n behalf ot the l .ittlc flocking Wates Association ["1.1i1M`A"), 1 am writing to submit 

comments 

(

010 the I'ccr Consultation Panel's ("Pt,'P'°) 1une 4, -2009 Draft Final Rqacut 

.'Report, .} 

We appreciate the PCPs consideration of the earlier LtiWA comments on the March 16, 

2tltl9 Preliminary Report of the PCP (The INWA comment letter of March 30, 2009 is 

included in Appendix A of the 1"mtt Final Report ofthe PCP.) 

Me i'olkawinx two non.subxtantivr, factual changes need to be made in the interest of 

accuracy 

First, in the irnercst of accuracy and consistency we ask that references to our 

organizAtion be made as either "the Little Hmking Water AssacWion" or "the L"WA" 

Seccinu3 . Figure s of the Report provides a clearer urrderstanding of the i.H'rdV'A wellfiald 

data How-ever, t..HWA noted the following errors in the transfer of sorrte data : 

1 t TW-11S - the "scril PF(3A" valie for the 03 fm depth should be 43, not 

3 (reference Appendix 5 .8. Table 4 7f, 

TW-13D - the "soil PFAr'1" value for the b foot depth should be, 16, not 6 

{reference Appendix 5 8, Table 4 7) : 

Sample 5A the soil value forPI`OA at the 0 to I inch depth should be 

14 4. not. 1 .4 (reference Table 5 24) ; and 
TW-14Ct - all "soil PFC)A" values from tt inches to 22 feet are incorrectly 

stated tit appears as though the values arc for TW-1 5D) and should be 

placed opposite the quoted depths in the table, starting frtam the surfaee, as 

follows : 51, 3B, 29, 9.3, t$, 11, q 3, '9, 14, 11, 16, and 6.3 (tefttnce 

.Appendix 5.8, TabIe 4.7) 

In atditiort, LIiW A offers a limited comment om ort other issue. On pW 32 of the 

Report { Section .13 ? ?') the statement is made flat "Althoxgh Tr*.d-wttarrs errtSe as #o 

*het1e.r r.w rtto the grmrrrcJwut'er flow mock! dewrahed in the rejxwi Imr brew wcrltdrrJcd 

torcJ' ff ton, trcntr .~ce~.tr~~ were emjal'r~twd trcl roifirm,grrsradwcrl,er mosvmwthV, a l'A»ttatcl' 

.tiewrex tiefdogic~uf SOW F' 1'f"g,%s;i reprws f» 2t701-,5",J 1Jw .WMMM=s the Surv* :r 

geohtVrrxlcjV atwxwwnt aWsimulcxt'iort of gr5rmrxlrmler {fmw in the Ohio Rrwr allur,ral 

Multer,k inc:ltudtrg the hu*ersk+rg arm mpports ~dNs elainr ". It is unclev to LHWA 

how the USGS study, conducted in the vicinity of Parkersbtrg,Wtst Virginia (located 

about seven miles upstream from the L.HWA welli'~cld) validates DuPonts groundwater 

model 

The US+GS report did nut specifically model either the pumping conditions or the 

geological conditions in the i.titWA welifreltl . These condiitiam am extremely 

complicated dix to confounding factors such us multiple pumping centers and pooling, 

the Ohio River in a series of locks and dams. Consequently, them are many qu 

about the groundwater mode! 

l .11'pr'A supports the Report's recommendation that pump and tracer tests should be 

carried out to further explore hydraulic connections between the Ohio River waters near 

the Washington Works Site and groundwttten on bath sides of the OW River. 

.SMaMMY 

Once again, we appreciate the PCP's independent assessment of the data and the 

recornmvndatiaats for the Phw 111 work If the PCP has any questions about our 

comments or needs finiher information, please do not hesitate to contact us 

Sincerely, 

LITTLE HOCKING WATER ASSMIA`1"1t3N, INC.