Evidence of Antibiotic Resistant Genes Sorbed to Microplastics in Biosolids and Mobilized to Runoff

Microplastics (MPs) with accumulated Antibiotic Resistant Genes (ARGs) can be captured in biosolids and contaminate the terrestrial environment through biosolids land application. A field experiment with land-applied biosolids combined with rainfall simulations was conducted to control the biosolids loading, biosolids application methods, and rainfall events. The attached ARGs on MPs were analyzed from soil and runoff samples. Through biosolids application, some ARGs were significantly increased; tetW on MPs in soil increased 5-10 times. In runoff from biosolids-amended plots, the relative abundance of ARGs on MPs increased by 159% and 34%, as compared to the abundance in soil for spreading and incorporating plots, respectively. The biosolids application method affected the mobility of MPs and their associated ARGs to runoff, with surface spreading having the greatest mobility.