PFAS Toxicology – The Science Behind the Variation in Drinking Water Standards

In May 2016, the EPA issued lifetime health advisory levels for two perfluoroalkyl substances (PFAS), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) of 70 parts per trillion individually or for the sum of these chemicals. As of October 2019, the EPA has yet to establish enforceable maximum contaminant levels (MCL) for any of the PFAS. In the absence of a federal MCL, individual states are establishing drinking water standards and guidelines. In this review, we examine the different toxicological evidence utilized by state agencies in developing their standards, focusing on the points of departure and uncertainty in the development of these standards. © 2019 New England Water Works Association. All rights reserved.