Perfluorinated alkyl acids in bivalves, water, and sediments of the Po river delta (Adriatic Sea)

The river Po (Northern Italy) is the longest river in Italy (652 km) and it flows across the Pianura Padana eastward with a drainage area of 74,000 km² (about one fourth of the whole Italian surface) and more than 16 million people lived in the whole basin, nearly one third of the Italian population. The Po basin generates nearly 40% of the Italian national GDP through intensive industry and other economic activities. Among the industrial activities, an important fluoropolymer production plant is located in Po basin and it is the most significant source of PFOA in the basin1. Our previous study2 showed that the PFAS load from Po (about 4.1 t/y) still remains a significant contribution to the Adriatic Sea, even if PFOA load from river Po (1.7 t/y2) is significantly reduced respect to previous data (9.5 t/y1). The farming of mollusks is extensively developed in the lagoons of the Po Delta. Consequently, the bioaccumulation of these compounds in the aquatic trophic webs poses concern about the risks for end consumers, including humans. In this study, the concentrations of perfluorinated carboxylates (PFCA, from C5 to C10) and perfluorinated sulfonates (PFSA, C4 and C8) was determined in water, sediment, and in biota tissues of the mussel Mytilus galloprovincialis and the clam Venerupis philippinarum sampled in the Po Delta. The bioconcentration factors (BCFs) were also evaluated in bivalves. Being the bivalve species studied largely consumed in Italy, the Tolerable Daily Intake (TDI) was calculated in order to evaluate the risk for humans.