Issues in the hazard and risk assessment of perfluoroalkyl substance mixtures.

In its 2020 Scientific Opinion on the Risk to human health related to the presence of perfluoroalkyl substances in food, EFSA had to tackle the challenging task to evaluate the risk(s) posed by the potential presence of per- and polyfluoroalkyl substances (PFAS). The assessment had to cover 27 perfluoroalkyl carboxylates (PFCAs) and sulfonates (PFSAs) of variable chain length (C4-C18). Grouping such a large number of structurally diverse compounds - many with a limited exposure and absent toxicity database - is a complex task. Our commentary summarizes some of the issues and pitfalls in this assessment.