Fate of antibiotic resistance genes in arsenic and antibiotic co-contaminated paddy soil regulated by composts-derived humic substances

Due to providing persistent selection pressure, antibiotic resistance genes (ARGs) can potentially threaten the clean production of rice in heavy metal-antibiotic co-contaminated paddy soil. As an important reservoir of soil carbon, it is not clear how humic substances (HS) from different manures coupled with other elements to regulate the fate of ARGs in co-contaminated paddy soils. This study compared the characteristics of fulvic (FA) and humic (HA) acids extracted from pig manure (PM), cow dung (CD), and chicken manure (CM). The effects of different doses of FA and HA addition on ARGs in arsenic (As)-antibiotic co-contaminated paddy soil were investigated, including both biotic and abiotic processes.