Retrospective Exposure Estimation and Predicted versus Observed Serum Perfluorooctanoic Acid Concentrations for Participants in the C8 Health Project
News Sep 16, 2011
People living or working in eastern Ohio and western West Virginia have been exposed to perfluorooctanoic acid (PFOA) released by the DuPont Washington Works facilities.
To estimate historical PFOA exposures and serum concentrations experienced by 45,276 non-occupationally exposed participants in the C8 Health Project who consented to share their residential histories and a 2005-2006 serum PFOA measurement.
We estimated annual PFOA exposure rates for each individual based on predicted calibrated water concentrations and predicted air concentrations using an environmental fate and transport model, individual residential histories, and default assumptions from the EPA Exposure Factors Handbook. We coupled individual exposure estimates with a one-compartment ADME (absorption, distribution, metabolism, and excretion) model to estimate time-dependent serum concentrations. Results: For all participants (n = 45,276), predicted and observed median serum concentrations in 2005-2006 are 14.2 and 24.3 ppb, respectively (Spearman's rho = 0.67). For participants who provided daily public well water consumption rate and who had the same residence and workplace in one of six municipal water districts for five years before the serum sample (n = 1,074), predicted and observed median serum concentrations in 2005-2006 are 32.2 and 40.0 ppb, respectively (Spearman's rho = 0.82).
These individualized retrospective exposure and serum estimates are being used in a variety of epidemiologic studies being conducted in this region.
The article is published online in Environmental Health Perspectives and is free to access.