Breakdown products of the fungicide Fludioxonil may account for observed environmental impact: potential implications for human health.

Background: Fludioxonil fungicide has been shown to rapidly degrade in the environment into a perfluoroalkyl substance (PFAS) breakdown product. Fludioxonil has been previously associated with both health and environmental damage, but a clear mechanism has not been proven and reports of toxic effect have been troublingly inconsistent. Methodology: This review collects references from 2012-2025 detailing the extent of ecological impact and human health effects ascribed to fludioxonil. An effort was made to focus on points of similarity to shed light on potential mechanisms. Results: It is found that prior observations of toxic effect may be explicated by an elicitation of oxidative stress. We illustrate here that a primary breakdown product of fludioxonil includes a maleimide moiety, a chemical structure capable of irreversibly binding biological thiols like glutathione (GSH). This is relevant because damaging this key component of cellular anti-oxidant defense is known to be causal for increased oxidative stress. Conclusions: A mechanism of toxicity based on GSH depletion is consistent with previously unexplained toxicity issues ascribed to this fungicide, emphasizing the potential threat to both agriculture-adjacent aquatic biomes (from fish to phytoplankton) and human health.