Department of Environment and Energy, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea.
Department of Environment and Energy, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, 05006, South Korea.
Chemosphere. 2024 May;355:141826. doi: 10.1016/j.chemosphere.2024.141826. Epub 2024 Mar 28.
Recent studies have increasingly focused on the occurrence of plastic leachate and its impacts on aquatic ecosystems. Nonetheless, the environmental fate of this leachate in the presence of abundant natural organic matter (NOM)-a typical scenario in environments contaminated with plastics-remains underexplored. This study investigates the photo-induced leaching behaviors of dissolved organic matter (DOM) from terrestrial-sourced particles (forest soil and leaf litter) and microplastics (MPs), specifically polystyrene (PS) and polyvinyl chloride (PVC), over a two-week period. We also examined the biodegradability and spectroscopic characteristics of the leached DOM from both sources. Our results reveal that DOM from microplastics (MP-DOM) demonstrates more persistent leaching behavior compared to terrestrial-derived DOM, even with lesser quantities per unit of organic carbon. UV irradiation was found to enhance DOM leaching across all particle types. However, the photo-induced leaching behaviors of fluorescent components varied with the particle type. The MP group exhibited a broader range and higher biodegradability (ranging from 19.7% to 61.6%) compared to the terrestrial-sourced particles (ranging from 3.7% to 16.5%). DOM leached under UV irradiation consistently showed higher biodegradability than that under dark conditions. Furthermore, several fluorescence characteristics of DOM, such as the protein/phenol-like component (%C2), terrestrial humic-like component (%C3), and humification index (HIX)-traditionally used to indicate the biodegradability of natural organic matter-were also effective in assessing MP-DOM (with correlation coefficients R = 0.6055 (p = 0.003), R = 0.5389 (p = 0.007), and R = 0.4640 (p = 0.015), respectively). This study provides new insights into the potential differences in environmental fate between MP-DOM and NOM in aquatic environments heavily contaminated with MPs.
最近的研究越来越关注塑料浸出液的发生及其对水生生态系统的影响。然而，在富含天然有机物 (NOM) 的情况下，这种浸出液的环境归宿——在受塑料污染的环境中典型的情况——仍未得到充分探索。本研究调查了陆地源颗粒（森林土壤和落叶）和微塑料（MPs），特别是聚苯乙烯（PS）和聚氯乙烯（PVC）中溶解有机物（DOM）的光诱导浸出行为，为期两周。我们还检查了这两种来源浸出 DOM 的生物降解性和光谱特征。我们的结果表明，与陆地源 DOM 相比，微塑料（MP-DOM）中的 DOM 具有更持久的浸出行为，即使每单位有机碳的浸出量较少。我们发现，UV 照射增强了所有颗粒类型的 DOM 浸出。然而，荧光成分的光诱导浸出行为因颗粒类型而异。与陆地源颗粒（3.7%至 16.5%）相比，MP 组的荧光范围更广，生物降解性更高（19.7%至 61.6%）。在 UV 照射下浸出的 DOM 始终比在黑暗条件下浸出的 DOM 具有更高的生物降解性。此外，DOM 的几个荧光特性，如蛋白/酚类成分（%C2）、陆地腐殖质样成分（%C3）和腐殖化指数（HIX）——传统上用于指示天然有机物的生物降解性——也能有效地评估 MP-DOM（相关系数 R = 0.6055（p = 0.003）、R = 0.5389（p = 0.007）和 R = 0.4640（p = 0.015））。本研究为受 MPs 严重污染的水生环境中 MP-DOM 和 NOM 之间环境归宿的潜在差异提供了新的见解。
