Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8855360 | Environment International | 2018 | 9 Pages |
Abstract
Around 350â¯millionâ¯tons of solid waste is disposed of in landfills every year globally, with millions of cubic meters of landfill leachates released into neighboring environment. However, to date, little is known about the variations of antimicrobial resistance (AMR) in on-site leachate treatment systems and its development in leachate-receiving water environment. Here, we quantified 7 subtypes of antibiotic resistance genes (ARGs), 3 types of culturable antibiotic resistant bacteria (ARB) and 6 subtypes of mobile genetic elements (MGEs) in the effluents from a combined leachate treatment process, including biological treatment (MBR), physical separation (UF), ultraviolet (UV) disinfection and advanced oxidation process (AOP). The contents of ARGs, ARB and MGEs were generally enriched by the MBR, but then decreased significantly along with the tertiary treatment process. However, in the effluent-receiving water samples, the abundance of dominant ARGs (i.e. ermB, sul1, blaTEM) increased by 1.5 orders of magnitude within 96â¯h, alongside a general increase of MGEs (~10.0â¯log10(copies/mL) and total ARB (~1100â¯CFU/mL). Structural correlation analyses reveal that target ARGs were closely associated with MGEs, particularly in effluent-receiving samples (Procrustes test; M2â¯=â¯0.49, Râ¯=â¯0.71, Pâ¯=â¯0.001); and occurrences of ARB were majorly affected by ARG's distribution and environmental conditions (e.g. nitrogen speciation) in effluent and recipient groups, respectively. This study indicates that current treatment technologies and operation protocols are not feasible in countering the development of AMR in effluent-receiving water environment, particularly in tidal rivers that are capable of retaining contaminants for a long residence time.
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Authors
Dong Wu, Ruoqi Ma, Huawei Wei, Kai Yang, Bing Xie,