Human Health Risk Assessment of Perfluoroalkyl Acids

Abstract

In this chapter, the major human health risk assessment activities that have been undertaken for human exposure to perfluoroalkyls, with emphasis on perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), have been summarized. Margin of exposure risk assessments, risk assessments based on dietary exposure, and the establishment of regulatory levels for PFOS and PFOA concentration in drinking water are covered in detail. Although a large and robust database exists for PFOS and PFOA that covers multiple health endpoints, data are more limited for other perfluoroalkyls. A brief review of the chemical/physical properties and hazard profiles of PFOS and PFOA in the context of risk assessment and human relevance is given. It becomes apparent that the methods used to assess human health risk from exposure to perfluoroalkyls have been evolving and will likely continue to develop as new information and approaches are introduced. Perhaps the most important direction that risk assessment for perfluoroalkyls has taken has been in the use of internal dose metrics to bridge differences in pharmacokinetic elimination kinetics between species. There is a need to better inform epidemiological investigations with the understanding obtained from toxicological and pharmacokinetic investigations and principals. Translating our understanding from toxicological systems into a human context will improve our collective ability to understand whether environmental exposure to perfluoroalkyls affects human health risk.