Water-level variations modulate ether-linked PFAS uptake and partitioning in emergent wetland plants

To investigate the remediation potential of wetland plants under varying hydrological conditions, this study evaluated five emergent macrophyte species to accumulate PFAS under simulated water-level variations. All species effectively accumulated PFAS, with Cyperus alternifolius showing the highest total mass retention.PFAS were predominantly stored in shoot tissues (47%-970% higher than in roots) under two water level conditions. Total PFAS accumulation per plant did not differ significantly between two water levels, high water conditions promoted root morphological plasticity (e.g., aerenchyma increased by 21%-340% across all species). Water-level rise increased overall root PFAS concentrations by an average of 2-fold without altering compound-specific preferences but inhibiting upward translocation (TF decreased by 38%-73%). These adaptive responses support a context-dependent remediation strategy: harvesting shoots at low water removes up to 68%-89% of accumulated ∑PFAS mass, while high water levels facilitate root sequestration of 25%-53% of ∑PFAS mass. Uptake was strongly influenced by PFAS molecular structure: root accumulation correlated positively with hydrophobicity (e.g., LogD_mw, Spearman's ρ = 0.34-0.72, p < 0.05), and PFOS showed the highest root bioconcentration (BCF_root = 120), likely due to strong adsorption. Short-chain compounds exhibited greater mobility and shoot accumulation (BCF_shoot up to 240). Ether-linked compounds such as GenX showed elevated shoot transfer capacity (TF values 1-4-fold those of carboxylate analogues). These findings provide a mechanistic basis for selecting species in nature-based PFAS remediation strategies within dynamic riparian ecosystems.