Su Yinglong, Zhang Zhongjian, Zhu Jundong, Shi Jianhong, Wei Huawei, Xie Bing, Shi Huahong
Shanghai Engineering Research Center of Biotransformation on Organic Solid Waste, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China; Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, East China Normal University, Shanghai, 200241, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
Shanghai Engineering Research Center of Biotransformation on Organic Solid Waste, Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China.
Environ Pollut. 2021 Feb 1;270:116278. doi: 10.1016/j.envpol.2020.116278. Epub 2020 Dec 11.
Microplastics (MPs) are found to be ubiquitous and serve as vectors for other contaminants, and the inevitable aging process changes MP properties and fates. However, whether the MPs in aging process affects the fates of antibiotic resistance gene (ARGs) in aquatic environments is poorly understood. Herein, the physicochemical property alteration of MPs being aged in landfill leachate, an important reservoir of MPs and ARGs, was investigated, and microbial community evolution and ARGs occurrence of MP surface during the aging process were analyzed. Aging process remarkably altered surface properties, including increasing specific surface areas, causing the formation of oxygen-containing groups, and changing surface morphology, which further increased the probability of microbial colonization. The bacterial assemblage on MPs showed higher biofilm-forming and pathogenic potential compared to leachate. ARGs quantification results suggested that MPs exhibited selective enrichment for ARGs in a ratio of 5.7-10 folds, and the aging process enhanced the enrichment potential. Further co-occurrence networks suggested that the existence of non-random, closer and more stable ARGs-bacterial taxa relations on MP surface affected the ARG transmission. The study of ARG partitioning on MPs indicated that extracellular DNA was a nonnegligible reservoir of ARGs attached on MP surface, and that biofilm bacterial community influenced ARGs partitioning pattern during the aging process. This study confirmed that the aging process could enhance the potential of MPs as vectors for ARGs, which would promote the holistic understanding of MP behavior and risk in natural environments.
微塑料（MPs）被发现无处不在，并作为其他污染物的载体，而且不可避免的老化过程会改变微塑料的性质和归宿。然而，老化过程中的微塑料是否会影响水生环境中抗生素抗性基因（ARGs）的归宿，目前还知之甚少。在此，我们研究了在垃圾渗滤液（微塑料和抗生素抗性基因的一个重要储存库）中老化的微塑料的物理化学性质变化，并分析了老化过程中微塑料表面的微生物群落演变和抗生素抗性基因的出现情况。老化过程显著改变了表面性质，包括增加比表面积、导致含氧基团的形成以及改变表面形态，这进一步增加了微生物定殖的可能性。与渗滤液相比，微塑料上的细菌群落表现出更高的生物膜形成和致病潜力。抗生素抗性基因定量结果表明，微塑料对抗生素抗性基因表现出5.7至10倍的选择性富集，并且老化过程增强了这种富集潜力。进一步的共现网络表明，微塑料表面存在非随机、更紧密和更稳定的抗生素抗性基因-细菌分类群关系，影响了抗生素抗性基因的传播。对抗生素抗性基因在微塑料上的分配研究表明，细胞外DNA是附着在微塑料表面的抗生素抗性基因的一个不可忽视的储存库，并且生物膜细菌群落在老化过程中影响了抗生素抗性基因的分配模式。这项研究证实，老化过程可以增强微塑料作为抗生素抗性基因载体的潜力，这将促进对微塑料在自然环境中的行为和风险的全面理解。
