Emerging perfluoroalkyl substance impacts soil microbial community and ammonia oxidation

Legacy perfluoroalkyl and poly-fluoroalkyl substances (PFASs) are gradually phased out because of their persistence, bioaccumulation, toxicity, long-distance transport and ubiquity in the environment. Alternatively, emerging PFASs are manufactured and released into the environment. It is accepted that PFASs can impact microbiota, although it is still unclear whether emerging PFASs are toxic towards soil microbiota. However, it could be assumed that OBS could impact soil microorganisms because it had similar chemical properties (toxicity and persistence) as legacy PFASs. The present study aimed to explore the influences of an emerging PFAS, namely sodium p-perfluorous nonenoxybenzene sulfonate (OBS), on archaeal, bacterial, and ammonia-oxidizing archaea (AOA) and bacteria (AOB) communities and ammonia oxidation. Grassland soil was amended with OBS at different dosages (0, 1, 10 and 100 mg/kg). After OBS amendment, tolerant microorganisms (e.g., archaea and AOA) were promoted, while susceptive microorganisms (e.g., bacteria and AOB) were inhibited. OBS amendment greatly changed microbial structure. Potential nitrifying activity was inhibited by OBS in a dose-dependent manner during the whole incubation. Furthermore, AOB might play a more important role in ammonia oxidation than AOA. Overall, OBS influenced ammonia oxidation by regulating the activity, abundance and structure of ammonia-oxidizing microorganisms, and could also exert influences on total bacterial and archaeal populations.