Shi_2026_Environ.Pollut__128205

Pyriproxyfen (PYR), as a sanitary insecticide, is widely used in agricultural applications and vector control programs for controlling pest breeding sites, and it inevitably enters aquatic ecosystems and transforms into a series of degradation products during applications. However, the effects of pyriproxyfen and its degradation products on non-target organisms in aquatic ecosystems have not been fully explored. In this study, zebrafish embryos (6-120 hours post-fertilization) were used as a model to explore the acute toxicity and developmental toxicity of pyriproxyfen and its nine degradation products. Pyriproxyfen (PYR) caused moderate acute toxicity in zebrafish embryos, while its degradation products 4'-OH-PYR and 5''-OH-PYR showed higher toxicity; most other degradation products showed lower acute toxicity. During early development, pyriproxyfen degradation products reduced embryo hatching rates, induced malformations, disrupted antioxidant balance and promoted apoptosis. Based on the screening results, three representative degradation products (4'-OH-PYR, 4-OH-POP, and PYPAC) were selected for further investigation of neurotoxicity. These degradation products were found to impair larval locomotor capacity by suppressing acetylcholinesterase activity, altering neurotransmission, and disrupting neuromuscular development through downregulation of key genes. These findings enhance our understanding of the developmental effects of pyriproxyfen on non-target organisms in the environment carry substantial implications for the comprehensive evaluation of its ecological and health-related risk profiles.