Multigenerational reproductive impairment induced by a perfluoroether sulfonate in Daphnia magna

Per- and polyfluoroalkyl substances (PFASs) have raised global concern due to their persistence and potential long-term ecological effects, prompting the use of alternatives such as perfluoroether sulfonates (PFESAs). However, ecotoxicological data for PFESA compounds, particularly regarding long-term impacts, remain scarce. This study systematically evaluated the acute, chronic, and multigenerational toxicity of potassium perfluoro(4-methyl-3,6-dioxaoctane) sulfonate (PFMDS) using Daphnia magna as a freshwater model. Acute toxicity testing revealed relatively low toxicity, accompanied by variable reactive oxygen species (ROS) responses. In contrast, chronic and continuous multigenerational exposure (F0-F2) affected multiple life-history traits, including somatic growth, reproductive timing, and offspring production. In F0, exposure at 15.0-20.0 mg/L significantly reduced fecundity and inhibited growth. Reproductive output also showed a decreasing tendency in F2 at 10.0 mg/L, while molting frequency remained largely unchanged despite growth impairment. Transcriptional analysis revealed significant downregulation of vitellogenin-related genes in F0 adults and juvenile hormone esterase in both F0 and F2 adults, suggesting alterations in endocrine-related regulatory processes. Together, these findings demonstrate that chronic PFMDS exposure can affect multiple life-history and molecular endpoints across successive generations, highlighting the importance of multigenerational approaches for identifying the potential hazards of emerging PFESA alternatives.