Thesis title: Marine health and human health: definition of chemical profiles of persistent contamination in the seas and oceans of the planet through validation of sampling methods, analysis and quality assurance for emerging chemical contaminants.
Per- and polyfluoroalkyl substances (PFAS) constitute a large and heterogeneous class of synthetic organofluorine compounds widely employed for their unique physicochemical properties, such as thermal stability, surfactant behavior, and resistance to degradation. These characteristics, while making PFAS technologically valuable in applications including textiles, food packaging, cosmetics, firefighting foams, construction materials, oil recovery, pesticides, and medical devices, also confer high environmental persistence, bioaccumulative potential, and mobility. Consequently, PFAS have been classified as contaminants of emerging concern.
Once discharged, they undergo long-range atmospheric and oceanic transport, resulting in global contamination of air, soil, water, sediments, and marine systems. Oceans represent major sinks for PFAS, but re-emission through sea spray aerosols contributes to their continuous cycling. Bioaccumulation and biomagnification, particularly of long-chain perfluoroalkyl acids (PFAAs) such as PFOS and PFOA, have been extensively documented. Human biomonitoring programs have consistently confirmed widespread exposure through food, drinking water, consumer products, and indoor environments. Epidemiological and toxicological evidence links PFAS exposure to immunotoxicity, endocrine disruption, hepatotoxicity, reproductive toxicity, developmental effects, and elevated cancer risk. These findings have driven international regulatory initiatives, including restrictions under the Stockholm Convention, binding European limits in drinking water and biota, and recent enforceable US EPA standards.
In this context, the present doctoral research, developed within the Sea Care project in collaboration with the Italian Navy and the National Institute of Health (ISS), focused on the development and validation of a sensitive multi-residual liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the trace-level determination of 30 PFAS in seawater. Sample preparation was performed via solid-phase extraction (SPE). Method validation yielded limits of detection and quantification in the ng/L range, with isotopically labeled internal standards ensuring accuracy and reproducibility. Specifically, LODs ranged from 0.003 to 0.05 ng/L, while LOQs were established between 0.006 and 0.15 ng/L. Quality control stability tests demonstrated robustness, with most analytes showing relative standard deviations below 20%. Particular attention was devoted to minimizing system- and solvent-derived contamination, including the replacement of fluoropolymer components with PEEK tubing, the use of polypropylene vials and PFAS-free solvents, and the introduction of a reversed-phase delay column.
The validated protocol was applied to 137 seawater samples collected from 86 sites during the SeaCare 2022–2025 international monitoring campaign, covering the Atlantic Ocean, Mediterranean Sea, Arctic Ocean, Red Sea, Persian Gulf, and Indian and Pacific Oceans, with both surface and deep-water layers investigated. Results revealed widespread PFAS occurrence, including detection in remote regions such as the Arctic Ocean, confirming their long-range transport capacity. The highest concentrations (>40 ng/L Σ30PFAS) were observed in industrialized or traffic-intensive areas such as Venice, Ravenna, Dubai, and Doha, where PFBA, PFHxA, PFOA, PFNA, PFOS, and emerging PFAS including ADONA and FBSA were most frequently detected.
Overall, this work demonstrates the reliability of the validated LC–MS/MS method for trace PFAS quantification in complex marine matrices and provides new insights into their global occurrence, transport mechanisms, and potential ecotoxicological implications, contributing to improved risk assessment strategies and regulatory frameworks for the protection of human health and ecosystems.