Depuration of ingested ¹⁴C-labelled polystyrene nanospheres in the Atlantic scallop (Placopecten magellanicus)

The presence of nano-plastics in marine bivalves is well established and may represent a risk to human consumption. The main objective of our work was to study the detailed tissue distribution of 14C-radiolabelled polystyrene nanospheres (PSNP; 325 nm) following their ingestion by commercial-size Atlantic scallop (Placopecten magellanicus) using whole-body autoradiography to assess their translocation, bioaccumulation and depuration mechanisms over a short-term exposure (6h) and a long-term exposure (2 weeks). Results showed that the nanospheres (PSNP) did not accumulate in scallop tissues despite the fact they were ingested and transported all along the digestive system. Elimination of the PSNP was virtually completed within 48 h and no radiolabeling appeared in the edible adductor muscle. This is indicative of the presence of an active depuration mechanism of particles without nutritional value as plastic PSNP. Our preliminary work indicates a rapid translocation of PSNP in scallops minimizing a possible transfer to human consumers.