Per- and Polyfluoroalkyl Substances Leaching from Micro- and Nanoplastics and the Associated Influence of the Plastisphere

Micro- and nanoplastics (MNPs) act as vectors for persistent organic pollutants in marine environments, yet their role in leaching of per- and polyfluoroalkyl substances (PFAS) remains poorly understood. We investigated PFAS leaching from MNPs during a 3-month seawater incubation experiment and explored the potential influence of the plastisphere on PFAS release dynamics. We quantified unknown PFAS using the total oxidizable precursor assay (TOPA) by converting oxidizable precursors into detectable perfluoroalkyl acids. Targeted chemical analysis quantified PFAS in MNPs and seawater leachates. While multiple PFAS were successfully solvent extracted (sequential extractions using acetonitrile:isopropanol and hexane) from various MNPs, detectable leaching into seawater occurred exclusively from polytetrafluoroethylene and fluorinated ethylene propylene MNPs. TOPA revealed the highest total PFAS concentrations in fluoropolymer MNPs, indicating the presence of oxidizable precursors and suggesting additional PFAS formation potential beyond the extractable fraction. A plastisphere-isolated bacterium significantly influenced the leaching of short-chain perfluoroalkyl carboxylic acids, specifically perfluoropentanoic acid, perfluorohexanoic acid, and perfluoroheptanoic acid, with the total PFAS concentration leached higher without than with bacteria. This finding suggests that marine microbial activity within the plastisphere may actively modulate the fate of MNP-bound PFAS, potentially altering their bioavailability and ecological impact.