Toxicity, bioaccumulation and metabolism of fluopyram in zebrafish (Danio rerio)

Fluopyram, a novel kind of succinate dehydrogenase inhibitor fungicides, has widespread utilized to control plant diseases or nematodes. However, the potential toxicity risks to non-target aquatic organisms of fluopyram have aroused wide concern. In this study, fluopyram was indicated as low toxic pesticide with 96 h LC₅₀ to adult zebrafish of 17.82 mg/L. Fluopyram was classified as a moderately bioaccumulation pesticide with the BCF in zebrafish of 15.22-21.62, and found tend to accumulate in viscera tissues of zebrafish. Metabolites of fluopyram in zebrafish and water were identified and the toxicities to aquatic organisms of fluopyram and its metabolites were predicted by calculation model. Meanwhile, the metabolic pathways were proposed based on the oxidation and hydroxylation reactions in phase I metabolism and following by glucuronidation in phase II. The activities of detoxification and metabolism enzymes and expressions of related genes preliminary elucidated detoxification processes. These findings enrich comprehension of the ecological risks posed by fluopyram and contribute to a better risk assessment for aquatic organisms and human health.