Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin, 541004, China.
Environ Res. 2023 Apr 1;222:115346. doi: 10.1016/j.envres.2023.115346. Epub 2023 Jan 23.
Large amounts of microplastics (MPs) enter the soil along with the amendment of sludge to soil. However, it is still unclear about the response of MPs occurrence and the adsorption behaviors of cadmium (Cd)on MPs to typical agricultural environmental scenarios. In present work, three kinds of MPs (polyethylene, polypropylene, and polystyrene) were chosen to investigate that response in three agricultural environmental scenarios with sludge-amended soil, including dry-wet alteration (7 d, five cycles), microbial addition (Bacillus subtilis, 0.05 g/g soil), and Ultraviolet (UV) irradiation (340 nm, 4 × 15 W, 4 d). The results showed that there was the highest adsorption capacity of Cd on MPs (36.21, 45.15, 12.43 μg/g for PE, PP, PS, respectively) after UV irradiation exceeding those from MPs triggered by other two scenarios). UV irradiation caused an increase in the abundance of Streptomyces, an expansion in specific surface area, a significant change in surface morphologies, an improvement in crystallinity or the formation of new crystals, and an enhancement in C-O and CO content, and then resulted in the incremental adsorption capacity of Cd on MPs. The findings are important of significance for controlling the environmental risks from sludge MPs via carrying heavy metals in the soil-plant systems.
大量微塑料（MPs）随污泥施用于土壤而进入土壤。然而，对于 MPs 的出现以及 Cd 在 MPs 上的吸附行为对典型农业环境情景的响应仍不清楚。在本工作中，选择了三种 MPs（聚乙烯、聚丙烯和聚苯乙烯）来研究污泥改良土壤中的三种农业环境情景中的响应，包括干湿交替（7d，五个周期）、微生物添加（枯草芽孢杆菌，0.05g/g 土壤）和紫外（UV）辐照（340nm，4×15W，4d）。结果表明，UV 辐照后 MPs 对 Cd 的吸附量最高（PE、PP、PS 分别为 36.21、45.15、12.43μg/g），超过了其他两种情景触发的 MPs。UV 辐照导致链霉菌丰度增加、比表面积扩大、表面形貌发生显著变化、结晶度提高或新晶体形成、C-O 和 CO 含量增加，从而导致 MPs 对 Cd 的吸附量增加。这些发现对于控制土壤-植物系统中污泥 MPs 携带重金属的环境风险具有重要意义。
