Fluxapyroxad induced toxicity of earthworms: Insights from multi-level experiments and molecular simulation studies

• Published in: Journal of hazardous materials 2024-12, Vol.480, p.135911, Article 135911
• Main Authors: Zhang, Lanlan, Liu, Yao, Xu, Ying, Pei, Mengyuan, Yao, Mengyao, Chen, Xiaoni, Cui, Yifei, Han, Fengyang, Lu, Yubo, Zhang, Cheng, Wang, Yanhua, Gao, Peng, Zhu, Lusheng, Wang, Jun
• Format: Article
• Language: English
• Subjects: Amides; Animals; Eisenia fetida; Fungicide; Fungicides, Industrial - toxicity; Intestinal injury; Molecular docking; Molecular Docking Simulation; Molecular Dynamics Simulation; Neurotoxicity; Oligochaeta - drug effects; Oxidative Stress - drug effects; Soil Pollutants - toxicity; Succinate Dehydrogenase - metabolism
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.135911

Fluxapyroxad, an emerging succinate dehydrogenase inhibitor fungicide, is widely used due to its excellent properties. Given its persistence in soil with a 50 % disappearance time of 183–1000 days, it is crucial to evaluate the long-term effects of low-dose fluxapyroxad on non-target soil organisms such as earthworms (Eisenia fetida). The present study investigated the impacts of fluxapyroxad (0.01, 0.1, and 1 mg kg−1) on Eisenia fetida over 56 days, focusing on oxidative stress, digestive and nervous system functions, and histopathological changes. We also explored the mechanisms of fluxapyroxad-enzyme interactions through molecular docking and dynamics simulations. Results demonstrated a significant dose-response relationship in the integrated biomarker response of 12 biochemical indices. Fluxapyroxad altered expression levels of functional genes and induced histopathological damage in earthworm epidermis and intestines. Molecular simulations revealed that fluxapyroxad is directly bound to active sites of critical enzymes, potentially disrupting their structure and function. Even at low doses, long-term fluxapyroxad exposure significantly impacted earthworm physiology, with effects becoming more pronounced over time. Our findings provide crucial insights into the chronic toxicity of fluxapyroxad and emphasize the importance of long-term, low-dose studies in pesticide risk assessment in soil. This research offers valuable guidance for the responsible management and application of fungicides. [Display omitted] •Long-term exposure to fluxapyroxad caused multi-level damage to Eisenia fetida.•Exposure to fluxapyroxad significantly induced lipid peroxidation and DNA damage.•Fluxapyroxad interacts with enzymes mainly, resulting in their structural changes.•Fluxapyroxad induced histopathological damage in both the epidermis and intestine.