Do conventional cooking methods alter concentrations of per- and polyfluoroalkyl substances (PFASs) in seafood?

Per-and poly-fluoroalkyl substances (PFASs) are bioaccumulative chemicals of emerging concern. Some PFASs accumulate in seafood, and can contribute to dietary exposure. Previous work has suggested cooking seafood decreases concentrations of neutral organic contaminants, however, previous studies dealing with PFASs have shown conflicting results. In this study, the potential changes of PFAS concentrations as a result of boiling, frying and baking are systematically examined. Blue Swimmer Crab (Portunus armatus), Dusky Flathead (Platycephalus fuscus) and School Prawn (Metapenaeus macleayi) were obtained from near a known PFAS point source and a reference location (affected by diffuse sources). Raw and cooked samples were analysed for commonly found PFASs. Of 23 target analytes, PFOS was the most frequently detected compound. PFOS, PFHxS and PFOA concentrations in School Prawn effectively doubled after boiling, and PFOS increased when Dusky Flathead was baked. There was no significant difference in PFOS concentration when Dusky Flathead was fried, or when the Blue Swimmer Crab was boiled. PFHxS and PFOA concentrations in Blue Swimmer Crab effectively halved after boiling. Increase in PFAS concentrations possibly arise from mass loss during the cooking process. Our data show that cooking does not consistently reduce PFAS concentrations, and cannot mitigate dietary exposure.