Overlooked health and ecotoxicological effects of PFOS alternatives: Evidence from wheat in soil

The elimination of perfluorooctane sulfonate (PFOS) has accelerated the widespread application and occurrence of alternatives, yet the health and ecotoxicological effects of these alternatives remain poorly understood. Therefore, this study employed microcosm experiments to evaluate the accumulation of PFOS and its alternatives in wheat, namely sodium p-perfluorous nonenoxybenzenesulfonate (OBS) and chlorinated polyfluorinaed ether sulfonates (F-53B), and effects on soil bacterial community. OBS and PFOS demonstrated comparable accumulation levels in ears with 0.29-23.8 ng/g, significantly exceeded those of F-53B at exposure of 200, 500, 1000, 2000 ng/g in soil. OBS demonstrated the strongest upward translocation capacity with a translocation factor of 0.89, and also exhibited a distinct concentration-dependent translocation pattern. Further Illumina MiSeq sequencing revealed that OBS induced the most pronounced microbial perturbations: under 2000 ng/g exposure, the Shannon index decreased by 4.30 %. Proteobacteria dominated across all treatments with proportions of 29.9 % ± 3.7 %. Notably, the genus Azotobacter was enriched by 383.5-fold at 2000 ng/g of OBS treatment compared to the control group, indicating its sensitivity to high OBS exposure. 15 keystone microbial taxa hypothesized to play crucial roles in maintaining community stability under PFASs stress. These findings highlight that OBS exhibits equivalent human intake and stronger microbial effects compared to PFOS. The potential risks of OBS warrant serious attention.