Occurrence of Per- and Polyfluoroalkyl Substances (PFAS) in Small Pelagic Fish from the Adriatic Sea: Evidence of PFOS Dominance

Per- and polyfluoroalkyl substances (PFAS) are a large group of synthetic chemicals widely used in industrial applications and consumer products due to their exceptional chemical and thermal stability. Their persistence in the environment and tendency to bioaccumulate have resulted in global distribution and growing concern regarding potential adverse effects on human health. In response, Commission Regulation (EU) 2023/915 established maximum levels for perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), and their sum in food of animal origin. According to the European Food Safety Authority (EFSA), fish and eggs are major dietary contributors to PFAS exposure in the general population.

Small pelagic fish, including European sardine (Sardina pilchardus) and Mediterranean sand smelt (Atherina hepsetus), were selected to investigate PFAS contamination in the Adriatic Sea. Specimens collected in 2024 were analyzed following extraction with acetonitrile and dispersive solid-phase extraction (dSPE) clean-up. PFAS concentrations were determined using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS).

PFOS was detected in all samples and was the dominant compound in both species. Concentrations ranged from 0.177 to 0.537 μg/kg in Mediterranean sand smelt and from 0.269 to 0.675 μg/kg in European sardine. PFHxS and PFNA were detected only in a subset of samples, while PFOA was not detected. The sum of regulated PFAS ranged from 0.177 to 0.655 μg/kg in sand smelt and from 0.269 to 0.726 μg/kg in sardine. Several long-chain PFAS, including FOSA, PFDA, and PFUnDA, were also identified in both species.

PFOS was consistently detected in all samples, suggesting widespread environmental contamination in the Adriatic Sea. As small pelagic fish constitute key prey for higher trophic-level organisms, these findings may indicate a potential risk for PFAS transfer and biomagnification within the marine food web.