Assessing the occurrence and human health risk of per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are a large group of fluorinated compounds with a wide range of industrial uses that result in human exposure to PFAS. Drinking-water is one of several environmental sources of human exposure to PFAS, along with exposure via food, use in consumer products and occupational exposures. Due to their persistence in the environment and impacts on environmental and human health, the World Health Organization (WHO) reviews the PFAS group of substances on an ongoing basis, as the state of the science evolves. WHO is currently identifying and prioritizing key ingested PFAS and key health effects of PFAS. In addition to the most widely studied PFAS, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), this initiative includes additional PFAS and the development of risk assessment methodology for prioritized PFAS, including individual PFAS and as mixtures. This work (Phase 1) sets the stage for the next phase of WHO initiatives to evaluate PFAS, which will employ these methodologies for the prioritized PFAS (Phase 2). These initiatives facilitate the Joint WHO/FAO Expert Committee on Food Additives (JECFA) and the WHO Guidelines for Drinking-water quality expert meetings in developing formal, normative health-based guidance values for key ingested PFAS (Phase 3).