Trial of a novel experimental design to test depuration of PFASs from the edible tissues of Giant Mud Crab following exposure under natural conditions in the wild.

Poly and perfluorinated alkyl substances (PFASs) are persistent organic pollutants (POPs) that are highly resistant to environmental degradation, and have been detected in a broad range of terrestrial and aquatic species. Portunid crabs have been shown to accumulate comparatively high concentrations of PFASs, but previous work examining depuration in crabs was inconclusive. Here, we trialled a novel experimental design to study depuration of PFASs from edible tissues of portunid crabs, using paired claw samples, and trial this design with Giant Mud Crab Scylla serrata exposed to the contaminant under natural conditions. We found evidence for depuration of perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA), but with depuration half-lives as high as 40 days (for PFOS). We also observed substantial variability in the data, including differences in PFAS concentrations between claws from the same individuals, potentially resulting from claw loss and re-growth prior to capture. These results have broad implications for assessing and minimising exposure risk in seafood species.