Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China..
Tianjin Key Laboratory of Clean Energy and Pollution Control, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
Water Res. 2024 Feb 15;250:121064. doi: 10.1016/j.watres.2023.121064. Epub 2023 Dec 24.
Microplastics (MPs) have emerged as a novel and highly concerning contaminant that is ubiquitous in the aqueous environment. However, the aging of MPs induced by dissolved organic matter (DOM), especially biochar-derived dissolved organic matter (BDOM), and the biological toxicity after aging are not fully understood. In this study, the effects of biochar-derived BDOMs on the photoaging and biotoxicity of MPs were investigated at different pyrolysis temperatures using micro-scale polyethylene (PE) as an example. The results showed that the amount of ·OH generated by the BDOM/PE systems was related to the molecular composition and structure of BDOMs. High temperature BDOM7/9 with less lignin-like (34.33 % / 41.80 %) and more lipid (24.58 % / 19.88 %) content could produce more ·OH by itself, and its binding ability with PE was weaker due to its less hydrophobic components (SUVA260 = 0.10 / 0.11), which resulted in a weaker shading effect and less inhibition of the system, thus resulting in more ·OH production in the high temperature BDOM7/9/PE system. However, the involvement of BDOM, although favoring the long-term stable ·OH production of the system, did not significantly promote the photoaging of MPs. Furthermore, combined in vivo and in vitro biotoxicity studies of MPs showed that photoaging PE with the involvement of BDOM greatly improved systemic inflammation and tissue damage, as well as reactive oxygen species (ROS, such as ·OH and -OH)-induced cell death. For example, the addition of BDOM5/PE-light reduced the cell death of human lung, liver, and kidney cells from 54.70 %, 69.39 %, and 48.35 % to 22.78 %, 33.13 %, and 25.83 %, respectively, compared to the PE-light group. The results of this study contribute to an in-depth understanding of the environmental behavior of BDOM and MPs systems.
微塑料 (MPs) 作为一种新型的高度关注的污染物，广泛存在于水环境中。然而，溶解有机质 (DOM) 诱导的 MPs 老化，特别是生物炭衍生的溶解有机质 (BDOM) 诱导的 MPs 老化，以及老化后的生物毒性，尚未得到充分的了解。在这项研究中，以微尺度聚乙烯 (PE) 为例，研究了不同热解温度下生物炭衍生的 BDOM 对 MPs 光老化和生物毒性的影响。结果表明，BDOM/PE 体系中产生的·OH 数量与 BDOM 的分子组成和结构有关。具有较少木质素样物质（34.33%/41.80%）和更多脂质（24.58%/19.88%）含量的高温 BDOM7/9 可以自身产生更多的·OH，并且由于其疏水性成分较少（SUVA260=0.10/0.11），与 PE 的结合能力较弱，导致遮蔽效应较弱，系统抑制作用较弱，从而在高温 BDOM7/9/PE 体系中产生更多的·OH。然而，BDOM 的参与虽然有利于系统中·OH 的长期稳定产生，但并没有显著促进 MPs 的光老化。此外，结合 MPs 的体内和体外生物毒性研究表明，BDOM 参与的光老化 PE 大大加剧了全身炎症和组织损伤，以及活性氧物种（如·OH 和 -OH）诱导的细胞死亡。例如，与 PE-光组相比，BDOM5/PE-光使人类肺、肝和肾细胞的细胞死亡率分别从 54.70%、69.39%和 48.35%降低到 22.78%、33.13%和 25.83%。这项研究的结果有助于深入了解 BDOM 和 MPs 系统的环境行为。
