School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China.
Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
J Hazard Mater. 2023 Apr 15;448:130718. doi: 10.1016/j.jhazmat.2022.130718. Epub 2023 Jan 2.
Previous knowledge of dissolved organic matter leached from microplastics (MP-DOM) was mainly based on the aquatic environment. The molecular characteristics and biological effects of MP-DOM in other environments have rarely been examined. In this work, FT-ICR-MS was applied to identify MP-DOM leached from sludge hydrothermal treatment (HTT) at different temperatures, and the plant effects and acute toxicity were investigated. The results showed that the molecular richness and diversity of MP-DOM increased with rising temperature, accompanied by molecular transformation in the meantime. The oxidation was crucial whereas the amide reactions mainly occurred at 180-220 C. MP-DOM promoted root development of Brassica rapa (field mustard) by affecting the expression of genes and the effect was enhanced with rising temperature. Specifically, the lignin-like compounds in MP-DOM down-regulated Phenylpropanoids biosynthesis, while CHNO compounds up-regulated the nitrogen metabolism. Correlation analysis presented that alcohols/esters leached at 120-160 C were responsible for the promotion of root, while glucopyranoside leached at 180-220 C was vital for root development. However, MP-DOM produced at 220 C showed the acute toxicity to luminous bacteria. Considering the further-treatment of sludge, the optimum HTT temperature could be controlled at 180 C. This work provides novel insight into the environmental fate and eco-environmental effects of MP-DOM in sewage sludge.
先前关于从微塑料（MP-DOM）中浸出的溶解有机质的知识主要基于水生环境。MP-DOM 在其他环境中的分子特征和生物效应很少被研究。在这项工作中，应用傅里叶变换离子回旋共振质谱（FT-ICR-MS）来鉴定不同温度下污泥热解吸（HTT）中浸出的 MP-DOM，并研究其对植物的影响和急性毒性。结果表明，随着温度的升高，MP-DOM 的分子丰富度和多样性增加，同时伴随着分子转化。氧化是关键的，而酰胺反应主要发生在 180-220°C。MP-DOM 通过影响基因表达促进了油菜（芥菜）的根系发育，并且随着温度的升高，这种促进作用增强。具体来说，MP-DOM 中的木质素样化合物下调了苯丙烷生物合成，而 CHNO 化合物则上调了氮代谢。相关性分析表明，在 120-160°C 浸出的醇/酯负责促进根系生长，而在 180-220°C 浸出的吡喃糖苷对于根系发育至关重要。然而，在 220°C 下产生的 MP-DOM 对发光菌具有急性毒性。考虑到污泥的进一步处理，最佳的 HTT 温度可以控制在 180°C。这项工作为了解 MP-DOM 在污水污泥中的环境归宿和生态环境效应提供了新的视角。
