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.

微塑料与纳米塑料（Micro- and nanoplastics, MNPs）可作为海洋环境中持久性有机污染物的载体，但其在全和多氟烷基物质（per- and polyfluoroalkyl substances, PFAS）浸出过程中的作用仍未被充分认知。我们通过为期3个月的海水培养实验，探究了MNPs中PFAS的浸出行为，并分析了塑料圈（plastisphere）对PFAS释放动力学的潜在影响。我们采用总可氧化前体物测定法（total oxidizable precursor assay, TOPA），将可氧化前体物转化为可检测的全氟烷基酸，以此对未知PFAS进行定量；同时通过靶向化学分析法，对MNPs及其海水浸出液中的PFAS开展定量检测。尽管通过乙腈-异丙醇与正己烷依次萃取法，可从多种MNPs中成功提取出多种PFAS，但仅聚四氟乙烯与氟化乙烯丙烯MNPs能向海水中检出PFAS浸出。总可氧化前体物测定法结果显示，含氟聚合物MNPs中的总PFAS浓度最高，这表明样品中存在可氧化前体物，且暗示除可萃取组分外，还存在额外的PFAS生成潜力。一株分离自塑料圈的细菌可显著调控短链全氟烷基羧酸的浸出过程，具体包括全氟戊酸、全氟己酸与全氟庚酸；且无细菌存在时，浸出的总PFAS浓度高于有细菌存在的实验组。该研究结果表明，塑料圈中的海洋微生物活动可主动调控MNPs结合态PFAS的归趋，进而可能改变其生物有效性与生态影响。