Barhoumi Badreddine, Metian Marc, Alonso-Hernández Carlos M, Oberhaensli François, Mourgkogiannis Nikolaos, Karapanagioti Hrissi K, Bersuder Philippe, Tolosa Imma
IAEA Marine Environment Laboratories, 4a Quai Antoine 1er, 98000, Principality of Monaco, Monaco.
Department of Chemistry, University of Patras, 26504 Patras, Greece.
Heliyon. 2024 Nov 16;10(23):e40490. doi: 10.1016/j.heliyon.2024.e40490. eCollection 2024 Dec 15.
Microplastics (MPs) are abundant in aquatic environments and due to their small size, surface properties, and strong hydrophobicity, they can easily sorb chemicals, thus potentially acting as pollutant carriers. To date, most studies investigating the sorption of chemicals on MPs have principally focused on virgin MPs. However, MPs in the environment undergo aging effects, which changes their physical-chemical properties and aptitude to interact with chemicals, such as per- and polyfluorinated alkyl substances (PFAS) referred to as "forever chemicals". In this study, we compared the sorption behavior of nine PFAS, exhibiting different physical-chemical properties, on virgin and naturally aged polystyrene microplastic (PS-MPs) to explore to what extent the environmental aging affects the sorption behavior of the PS-MPs for different legacy and emerging PFAS in seawater. Differences in the morphology and surface properties of aged PS-MPs were examined by infrared spectroscopy, surface area analysis, scanning electron microscopy, and X-ray diffraction. Results revealed that compared to virgin PS-MPs, aged PS-MPs exhibited morphological changes (e.g. cavities, pits, and rough surfaces) with biofilm development and signs of oxidation on the MPs surface. PFAS sorption on PS-MPs was enhanced for the aged PS-MPs compared to virgin PS-MPs with K values ranging from 327 L kg for PFOA to 3247 L kg for PFOS in aged PS-MPs. The difference in sorption capacity was mainly attributed to the physical-chemical changes and the adhered biofilm observed in aged PS-MPs. Results also showed that virgin PS-MPs adsorb PFAS mainly through steric hindrance, while the aged PS-MPs may involve more complex sorption mechanisms. This research provides additional insights into the ability of aged MPs as potential carriers of legacy and emerging contaminants in the marine environment.
微塑料（MPs）在水生环境中大量存在，由于其尺寸小、表面特性以及强疏水性，它们能够轻易吸附化学物质，因此有可能充当污染物载体。迄今为止，大多数研究化学物质在微塑料上吸附情况的研究主要集中在原始微塑料上。然而，环境中的微塑料会经历老化过程，这会改变它们的物理化学性质以及与化学物质相互作用的能力，比如全氟和多氟烷基物质（PFAS）这类被称为“永久性化学物质”的物质。在本研究中，我们比较了九种具有不同物理化学性质的PFAS在原始聚苯乙烯微塑料（PS-MPs）和自然老化的聚苯乙烯微塑料上的吸附行为，以探究环境老化在多大程度上影响PS-MPs对海水中不同传统和新兴PFAS的吸附行为。通过红外光谱、表面积分析、扫描电子显微镜和X射线衍射研究了老化PS-MPs的形态和表面性质差异。结果显示，与原始PS-MPs相比，老化的PS-MPs呈现出形态变化（如空洞、凹坑和粗糙表面），且微塑料表面有生物膜形成和氧化迹象。与原始PS-MPs相比，老化PS-MPs对PFAS的吸附增强，老化PS-MPs中PFOA的K值范围为327 L/kg，PFOS的K值范围为3247 L/kg。吸附能力的差异主要归因于老化PS-MPs中观察到的物理化学变化和附着的生物膜。结果还表明，原始PS-MPs主要通过空间位阻吸附PFAS，而老化的PS-MPs可能涉及更复杂的吸附机制。本研究为老化微塑料作为海洋环境中传统和新兴污染物潜在载体的能力提供了更多见解。
