PM2.5-bound bioaerosols during landfill leachate treatment: A profile of human pathogens, virulence factors, and antibiotic resistance genes.

The bioaerosols contamination bind to PM2.5 leads to significant ecological and public health concerns, but studies on the bioaerosols contamination bind to PM2.5 during landfill leachate treatment are rare. This study comprehensively investigated the behavior of PM2.5-bound bioaerosols and the potential pathogenicity that subsequently occurs during landfill leachate treatment. The results revealed that the mass concentration of PM2.5 was the lowest in the evaporation treatment workshop (ETW) and the highest in the biochemical treatment workshop (BTW). Burkholderia and Aureobasidium were the dominant strains in PM2.5. The SO42- content in PM2.5 was significantly positively correlated with the Burkholderia and Aquabacterium abundances, whereas the Cl-, NO3- and NO2- contents were negatively correlated with the Burkholderia and Ralstonia abundances. Burkholderia cepacia, Ralstonia pickettii and Stenotrophomonas maltophilia were the dominant bacterial pathogens. Hundreds of virulence factor genes (VFGs) and subtypes of antibiotic resistance genes (ARGs) were detected in PM2.5 during landfill leachate treatment, especially in the advanced membrane treatment of leachate and the evaporation treatment of concentrated leachate. VFGs and ARGs cooccur widely in PM2.5-associated microbes, especially in Burkholderia and Pseudomonas. This study helps increase the understanding of the pollution behavior and potential disease risk of aerosol particles during landfill leachate treatment.