Men Cong, Pan Zixin, Liu Jiayao, Miao Sun, Yuan Xin, Zhang Yanyan, Yang Nina, Cheng Shikun, Li Zifu, Zuo Jiane
Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants, School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
State Key Laboratory of Regional Environment and Sustainability, School of Environment, Tsinghua University, Beijing 100084, China.
Molecules. 2025 Mar 26;30(7):1464. doi: 10.3390/molecules30071464.
Microplastics and heavy metal contamination frequently co-occur in stormwater filtration systems, where their interactions may potentially compromise nitrogen removal. Current research on microplastics and Cd contamination predominantly focuses on soils and constructed wetlands, with limited attention given to stormwater filtration systems. In this study, the single and synergistic effects of aged polyethylene microplastics (PE) and cadmium (Cd) contamination in stormwater infiltration systems were investigated from perspectives of nitrogen removal, microbial community structures, and predicted functional genes in nitrogen cycling. Results showed that PE single contamination demonstrated stronger inhibition on NO-N removal than Cd. Low-level PE contamination (PE content: 0.1% /) in Cd-contaminated systems showed stronger inhibitory effect than high-level PE contamination (PE content: 5% /). The mean NO-N removal efficiency under combined Cd50 (Cd concentration: 50 μg/L) and PE5 contamination during the sixth rainstorm event was 1.04 to 34.68 times that under other contamination scenarios. Metagenomic analysis identified keystone genera (, , , etc.), and critical nitrogen transformation pathways (nitrate reduction to ammonium, denitrification, nitrogen fixation, and nitrification) govern system performance. PE and Cd contamination effects were most pronounced on nitrification/denitrification enzymes beyond nitrite oxidase and nitrate reductase. These mechanistic findings advance our understanding of co-contaminant interactions in stormwater filtration systems.
微塑料和重金属污染在雨水过滤系统中经常同时出现，它们之间的相互作用可能会影响脱氮效果。目前关于微塑料和镉污染的研究主要集中在土壤和人工湿地，对雨水过滤系统的关注较少。本研究从脱氮、微生物群落结构以及氮循环中预测的功能基因等方面，研究了老化聚乙烯微塑料（PE）和镉（Cd）污染对雨水入渗系统的单一和协同作用。结果表明，PE单一污染对NO-N去除的抑制作用比Cd更强。Cd污染系统中低水平的PE污染（PE含量：0.1% /）比高水平的PE污染（PE含量：5% /）表现出更强的抑制作用。在第六次暴雨事件中，Cd50（Cd浓度：50 μg/L）和PE5联合污染下的平均NO-N去除效率是其他污染情景下的1.04至34.68倍。宏基因组分析确定了关键属（如， ， ，等），以及关键的氮转化途径（硝酸盐还原为铵、反硝化、固氮和硝化）决定了系统性能。PE和Cd污染对亚硝酸氧化酶和硝酸还原酶以外的硝化/反硝化酶的影响最为显著。这些机理研究结果增进了我们对雨水过滤系统中共污染物相互作用的理解。
