State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai, 201306, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Environ Pollut. 2022 Oct 1;310:119859. doi: 10.1016/j.envpol.2022.119859. Epub 2022 Aug 6.
The environmental risks of microplastics (MPs) have raised an increasing concern. However, the effects of MPs in anaerobic digestion (AD) systems of waste activated sludge (WAS), especially on the fate of antibiotic resistance genes (ARGs), have not been clearly understood. Herein, the variation and interaction of digestion performance, microbial communities and ARGs during AD process of WAS in the presence of polyethylene (PE) MPs with two sizes, PE MPs-180μm and PE MPs-1mm, were investigated. The results showed that the presence of PE MPs, especially PE MPs-1mm, led to the increased hydrolysis of soluble polysaccharides and proteins and the accumulation of volatile fatty acids. The methane production decreased by 6.1% and 13.8% in the presence of PE MPs-180μm and PE MPs-1mm, respectively. Together with this process, hydrolytic bacteria and acidogens were enriched, and methanogens participating in acetoclastic methanogenesis were reduced. Meanwhile, ARGs were enriched obviously by the presence of PE MPs, the abundances of which in PE MPs-180μm and PE MPs-1mm groups were 1.2-3.0 times and 1.5-4.0 times higher than that in the control by the end of AD. That was associated with different co-occurrence patterns between ARGs and bacterial taxa and the enrichment of ARG-hosting bacteria caused by the presence of PE MPs. Together these results suggested the adverse effects of PE MPs on performance and ARGs removal during AD process of WAS through inducing the changes of microbial populations.
微塑料 (MPs) 的环境风险引起了越来越多的关注。然而， MPs 在废活性污泥 (WAS) 厌氧消化 (AD) 系统中的影响，特别是对抗生素耐药基因 (ARGs) 的命运的影响，尚未得到清楚的理解。在此，研究了在两种尺寸的聚乙烯 (PE) MPs（PE MPs-180μm 和 PE MPs-1mm）存在下，WAS 在 AD 过程中的消化性能、微生物群落和 ARGs 的变化和相互作用。结果表明，PE MPs 的存在，特别是 PE MPs-1mm 的存在，导致可水解多糖和蛋白质的水解增加，挥发性脂肪酸的积累。在 PE MPs-180μm 和 PE MPs-1mm 的存在下，甲烷产量分别降低了 6.1%和 13.8%。伴随着这个过程，水解细菌和产酸菌得到了富集，而参与乙酸型产甲烷的产甲烷菌减少。同时，ARGs 明显富集，PE MPs-180μm 和 PE MPs-1mm 组的 ARGs 丰度分别比 AD 结束时对照提高了 1.2-3.0 倍和 1.5-4.0 倍。这与 ARGs 和细菌分类群之间的不同共存模式以及 PE MPs 的存在导致的 ARG 宿主细菌的富集有关。这些结果表明，PE MPs 通过诱导微生物种群的变化，对 WAS 的 AD 过程中的性能和 ARGs 去除产生了不利影响。
