“…Similarly, the toxicological studies have primarily focused on the toxicity of the PFAAs (PFOA, PFOS, PFNA, PFHxA, PFBS and PFHxS) and to some extent of the FTOHs, whereas the literature is scarce on the toxicity and risk assessment of the polyfluorinated precursors of PFAAs (D'eon, 2011 a and b, D'eon 2014, Rosenmai et al, 2013, Wang et al, 2014 and other fluorinated alternatives such as the PFPEs (Trier 2011, Dimzon 2014. This data gap in both exploratory and confirmatory research on toxicity, exposure and of possibly unknown sinks of PFAA precursors makes it very difficult to assess which sources are the most relevant for human exposure-and hence whether there are a few sources which would be most efficient to regulate.…”