摘要

       微塑料（MPs）被发现无处不在，并作为其他污染物的载体，不可避免的老化过程会改变微塑料的特性和命运。然而，老化过程中的微塑料（MPs）是否会影响水生环境中抗生素抗性基因（ARGs）的命运在此，研究了垃圾渗滤液中 MPs 的理化性质变化，垃圾渗滤液是 MPs 和 ARGs 的重要储存库，分析了老化过程中 MPs 表面的微生物群落演化和 ARGs 的发生。老化过程显着改变表面特性，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植的可能性。与渗滤液相比，MPs 上的细菌组合显示出更高的生物膜形成和致病潜力。定量结果表明 MPs 对 ARGs 表现出选择性富集比例为 5.7-103 倍，老化过程增强了富集潜力。进一步的共生网络表明 MP 表面上非随机的、更紧密和更稳定的 ARGs-细菌类群关系的存在影响了 ARG 的传输。 MPs 上的 ARG 分配研究表明，细胞外 DNA 是附着在 MP 表面的不可忽略的 ARGs 库，生物膜细菌群落影响衰老过程中的 ARGs 分配模式。这项研究证实，衰老过程可以增强 MP 作为 ARG 载体的潜力，这将促进对自然环境中 MP 行为和风险的整体理解。
       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 5.7–103 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.
https://www.sciencedirect.com/science/article/abs/pii/S0269749120369670