Bioaccumulation of perfluorinated alkyl acids in bivalves of the Po river delta (Adriatic Sea)

The river Po (north of Italy) is the major Italian river and in its basin fluoropolymer manufacturing facilities and industrial activities, where perfluorochemicals are widely used, are present. In 2006 it was recognized as the dominant source of PFOA in Europe. In the lagoons of the Po River delta the farming of molluscs is extensively developed. Consequently, the accumulation of these compounds in the aquatic trophic chain poses concern about the risks for end consumers, including humans. In this study an assessment of the contamination by perfluoroalkyl acids (PFAAs) of water, sediment, mussels and clams of the Sacca di Goro Lagoon located in the southern part of the Po River Delta was performed. Analysis of perfluorinated carboxylates (from C5 to C10) and perfluorinated sulfonates (C4 and C8) were carried out by LC-MS/MS coupled with on-line SPE for analysis of water samples and on-line turbulent flow chromatography for purification of the extracts of sediment and biota samples. PFPeA, PFHxA, PFHpA, PFBS and PFHxS were never detected in the mollusc samples. In mussels, the detected PFAAs had similar concentrations ranging from 0.10 to 0.41 ng/g ww. On the other hand, PFOA and PFOS were the dominant homologues in clams with concentration from 2.2 to 4.5 ng/g ww and from 0.59 to 1.13 ng/g ww for PFOA and PFOS, respectively. The pattern of contamination in clams and mussels agrees with the literature data on PFAS contamination in bivalves. Considering the Italian average daily consumption of fresh and frozen shellfish (4.6 g/person) there is no health risk arising from dietary exposure to PFOS and PFOA at levels found in mollusk collected in the Sacca di Goro lagoon of Po River Delta.