Integrated analytical strategies supporting risk assessment of emerging contaminants in marine ecosystems

Emerging chemical contaminants pose a challenge for environmental protection and human health, particularly in marine ecosystems where dilution coexists with long-term accumulation. Among these, per- and polyfluoroalkyl substances (PFASs) are of primary concern due to their extreme persistence, high water solubility, and resistance to degradation, promoting widespread occurrence and long-range transport. This study aimed to develop and validate a sensitive multi-residue analytical strategy for PFAS determination in seawater, designed to integrate chemical data with ecological evaluation approaches. A solid-phase extraction–liquid chromatography–tandem mass spectrometry (SPE–UPLC–MS/MS) method was optimised for the simultaneous quantification of 30 PFASs. Water samples (500 mL) were subjected to freezing and thawing prior to extraction with Oasis WAX cartridges, followed by HPLC–MS/MS analysis. Chromatographic separation employed a dual-column setup (Accucore C18 delay column and Polar Advantage II analytical column) using a methanol–water gradient containing ammonium acetate and acetic acid, ensuring retention of both short- and long-chain PFASs while minimising background contamination. The method demonstrated excellent analytical reproducibility, chromatographic performance, and sensitivity, with detection limits of 0.01–2.5 ng/L. A matrix-adapted limit of quantification was applied to account for background contamination in blank seawater, ensuring reliable quantification of environmental samples. The analytical performance achieved enables the generation of occurrence data suitable for integration with exposure assessment models. Application of the validated method to Mediterranean seawater samples revealed a widespread but spatially heterogeneous distribution of PFASs. Concentrations were generally below 10 ng/L, with localised maxima up to 18 ng/L in industrialised and port-influenced areas of the Eastern Adriatic and Tyrrhenian Sea, while lower levels (≤1.7 ng/L) were observed in the Western and Southern Mediterranean. The simultaneous detection of regulated PFASs and emerging substitutes confirms the suitability of the proposed strategy for supporting PFAS risk assessment in marine ecosystems.