School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing, 210044, China.
School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing, 210044, China.
Chemosphere. 2022 Dec;308(Pt 1):136185. doi: 10.1016/j.chemosphere.2022.136185. Epub 2022 Aug 28.
Tire wear particles (TWPs) are considered to be one of the major sources of microplastics (MPs) in sewers; however, little has been reported on the surface properties and photochemical behavior of TWPs, especially in terms of their environmental persistent radicals, leachate type, and response after photoaging. It is also unknown how TWPs influence the production of common pollutants (e.g., sulfides) in anaerobic biofilms in sewers. In our study, the effects of cryogenically milled tire treads (C-TWPs) and their corresponding photoaging products (photoaging-TWPs, A-TWPs) on anaerobic biofilm sulfide production in sewers and related mechanisms were studied. The results showed that the two TWPs at a low concentration (0.1 mg L) exerted no significant (p > 0.05) effects on sulfide yield, whereas exposure to a high concentration of TWPs (100 mg L) inversely affected sulfide yield, with A-TWPs exerting a significant inhibitory effect on sulfide yield in the sewers (p < 0.01). The main reason was that A-TWPs carried higher concentrations of reactive environmental persistent radicals on their surfaces after photoaging than C-TWPs, which could induce the formation of oxygen radicals. In addition, A-TWPs were more uniformly distributed in the wastewater system and could penetrate the biofilm to damage bacterial cells, and their ability to leach polycyclic aromatic hydrocarbons and heavy metals such as zinc additives enhanced their toxic effects. In contrast, C-TWPs contributed significantly to sulfide production (p < 0.01), primarily because of their low biotoxicity, ability to leach a considerable amount of sulfide, and stimulatory effect on anaerobic biofilm surface sulfate-reducing bacteria. Our study complements the toxicity studies of the TWPs particles themselves and provides insight on a new influencing factor for determining the changes in sulfide generation and control measures in sewers.
轮胎磨损颗粒（Tire wear particles，TWPs）被认为是污水中微塑料（Microplastics，MPs）的主要来源之一；然而，关于 TWPs 的表面性质和光化学行为，特别是关于其环境持久性自由基、浸出物类型以及光老化后的反应，报道甚少。TWPs 如何影响污水中厌氧生物膜中常见污染物（例如硫化物）的产生也不清楚。在我们的研究中，研究了低温研磨轮胎胎面（Cryogenically milled tire treads，C-TWPs）及其相应的光老化产物（photoaging-TWPs，A-TWPs）对污水中厌氧生物膜硫化物生成的影响及其相关机制。结果表明，两种 TWPs 在低浓度（0.1mg/L）下对硫化物生成没有显著影响（p>0.05），而暴露于高浓度 TWPs（100mg/L）则相反地影响硫化物生成，A-TWPs 对污水中硫化物生成有显著抑制作用（p<0.01）。主要原因是 A-TWPs 在光老化后表面携带更高浓度的反应性环境持久性自由基，这可以诱导自由基的形成。此外，A-TWPs 在废水系统中分布更均匀，可以穿透生物膜并破坏细菌细胞，其浸出多环芳烃和锌添加剂等重金属的能力增强了其毒性作用。相比之下，C-TWPs 对硫化物生成有显著贡献（p<0.01），主要是因为其低生物毒性、能够浸出大量的硫化物，以及对厌氧生物膜表面硫酸盐还原菌的刺激作用。我们的研究补充了 TWPs 颗粒本身的毒性研究，并提供了一个新的影响因素，以确定污水中硫化物生成的变化和控制措施。
