AN ASSESSMENT OF FEDERAL AND STATE PFOA DRINKING WATER GUIDELINES AND A PROBABILISTIC EVALUATION OF THE EPA PFOA HEALTH ADVISORY

Abstract

In 2016, the United States Environmental Protection Agency (USEPA) published a Lifetime Health Advisory (LHA) for Perfluorooctanoic acid (PFOA) of 0.07 µg/L. The aims of this study are to trace the basis for the health-based guidelines (federal and state) for PFOA in drinking water, and to evaluate the assumptions used by the USEPA in setting the LHA. Eighteen states enacted guidelines for PFOA water concentrations, ranging from 0.009 to 50 µg/L. We compared the standards across factors, including methodology, drinking water intake (DWI), relative source contribution (RSC), and health endpoint. In addition, the assumptions for the USEPA health advisory were evaluated using a Monte Carlo analysis that included distributions for drinking water intake in terms of L/kg body weight (BW) -day and the RSC. The USEPA LHA was equal to the 1st percentile of the distribution for lactating women and was less than the lowest percentile value of the distribution for the general population. We found that guidelines varied across states, and the RSC used by the USEPA for the LHA was highly conservative.