Impacts of disinfectant and antipyretic on aged ethylene-vinyl acetate copolymer microplastics in hospital wastewater: Resistance genes, microbial community and carbon source metabolism.

Global transmission of resistance genes (RGs) by non-antibiotic substances and microplastics (MPs) pollution deserves in-depth research and discussion. The impacts of the existence of benzethonium chloride (BZC) and acetaminophen (APAP) on pristine and aged ethylene-vinyl acetate copolymer (EVA) MPs in hospital wastewater had not been studied. In this study, RGs, microbial community composition and carbon source metabolism activity were explored on EVA plastisphere in hospital wastewater containing BZC and APAP. After aging treatment, EVA MPs showed an increase in particle size, cracks on the surface and changes in functional groups. Moreover, aged EVA MPs became an excellent carrier and transmitter of RGs and accelerated microbial colonization after soaking in wastewater containing BZC and APAP. The abundances of RGs in wastewater containing pollutants were 6.19-665.49 times higher than those in wastewater without pollutants. These results indicated that the coexistence of BZC and APAP had higher environmental risk compared with single existence. Furthermore, quaternary ammonium compounds RGs were enriched in wastewater and on plastisphere with the presence of BZC. Network analysis demonstrated that Nitrosomonas (5.76-25.25 %) and pathogen Legionella (0.01-40.75 %) had high abundances in wastewater and on plastisphere and the potential to transfer multiple RGs. This study will fill the knowledge gap on the changes in microbial community structure, RGs transmission and carbon source metabolism of pristine and aged EVA MPs in wastewater containing BZC and APAP.