Toxicity of novel fungicide inpyrfluxam to zebrafish (Danio rerio) embryos

The harmful impacts of succinate dehydrogenase inhibitor (SDHIs) fungicides on aquatic organisms have attracted wide attention in recent years. Inpyrfluxam is a novel SDHI fungicide launched in 2020. However, its toxic effect on aquatic organisms is still unclear. In this study, zebrafish (Danio rerio) embryos were exposed to inpyrfluxam to investigate the lethal and developmental toxicity of inpyrfluxam. The results showed that inpyrfluxam had strong lethality in zebrafish embryos, with 96 h-LC₅₀ of 0.063 mg/L. Inpyrfluxam induced severe teratogenic effects on zebrafish embryos including yolk sac edema, pericardial edema, and spinal curvature at 0.050 mg/L. Obvious inhibition of heartbeat was observed in embryos after exposure to 0.045 mg/L inpyrfluxam. In addition, the hatching rate and body length of embryos were significantly reduced by 0.055 mg/L of inpyrfluxam. In conclusion, inpyrfluxam shows strong lethal and developmental toxicity to zebrafish embryos, and its potential risk to aquatic organisms demands more attention. Our results are of important supplement for aquatic toxicology information of inpyrfluxam, and provide a scientific basis for rational use and environmental safety assessment of inpyrfluxam.