Mitigating Ecological Risks: Role of Arbuscular Mycorrhizal Symbiosis in Translocation and Transformation of Per- and Polyfluoroalkyl Substances in Constructed Wetlands

Arbuscular mycorrhizal fungi (AMF) are increasingly recognized for their potential to remediate per- and polyfluoroalkyl substances (PFASs) in constructed wetlands (CWs), but their mechanisms in affecting PFAS removal remain unclear. This study aims to elucidate AMF's impacts on PFAS removal and their role in mitigating the environmental risks posed by residual PFASs in the effluent. The results indicated that the primary removal pathways of PFASs in CWs were substrate adsorption and microbial degradation, while plant uptake contributed minimally (0.2-0.3%). AMF enhanced host plant absorption and translocation of PFASs, thereby increasing PFAS accumulation in plant tissues. Additionally, AMF promoted the enrichment of key microbes (e.g., Chloroflexi and Proteobacteria), which stabilized and enhanced the activity of the rhizosphere microbial network, facilitating PFAS biotransformation and degradation. Through the reinforcement of microbial degradation, substrate adsorption, and plant uptake pathways, AMF symbiosis significantly enhanced PFAS removal, increasing efficiency by 10.5-13.3% compared to treatments without AMF. Notably, long-chain (C > 7) PFASs pose higher ecological risks compared to short-chain (C ≤ 7) PFASs. AMF effectively reduced the ecological risks associated with residual PFASs and their metabolites in the effluent. The results highlight AMF's potential to improve PFAS removal in CWs and offer valuable insights for developing sustainable, high-efficiency pollution control strategies.