Unit of Toxicology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore 641046, India.
Unit of Toxicology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore 641046, India; Department of Zoology, PSG College of Arts & Science, Coimbatore, Tamil Nadu 641014, India.
Sci Total Environ. 2023 Jan 20;857(Pt 2):159425. doi: 10.1016/j.scitotenv.2022.159425. Epub 2022 Oct 14.
Difenoconazole is widely used to protect crops, fruits, and vegetables. However, this fungicide can enter aquatic environments and cause harmful effects to non-target organisms and induce little-known biological disorders. Thus, aiming to expand our knowledge about the ecotoxicity of difenoconazole on freshwater ichthyofauna, we aimed to determine the median lethal concentration (LC) of difenoconazole and evaluate its possible impacts from different toxicity biomarkers, using freshwater fish Labeo rohita as a model system. Using the probit analysis method, the 96 h LC value of difenoconazole in the fish was calculated as 4.5 mg L. Posteriorly, fish were exposed to two sublethal concentrations (0.45 mg L 1/10th and 0.9 mg L 1/5th LC value) for 21 days. A significant reduction of superoxide dismutase (SOD) and catalase (CAT) activity was noted in the gill, liver, and kidneys of fish compared to the control groups. The level of glutathione-S-transferase (GST) and lipid peroxidation (LPO) activity was higher in all vital tissues of difenoconazole-treated fish. Histological alterations in the gill include epithelial lifting, lamellar fusion, hypertrophy, and epithelial necrosis. At the same time, the liver showed pyknotic nucleus, vacuolation, cellular edema and tubular necrosis, shrinkage of glomeruli, vacuolation, and pyknotic nuclei in the kidney. DNA damage was increased significantly with tail formation based on the concentration and time-dependent manner. Therefore, our study confirms that the exposure of L. rohita to difenoconazole induces negative biological consequences and sheds light on the danger of this fungicide for freshwater fish species. We believe that studies like ours can support actions and strategies for the remediation/mitigation of aquatic pollution by difenoconazole and for the conservation of freshwater ichthyofauna.
烯唑醇被广泛用于保护农作物、水果和蔬菜。然而，这种杀菌剂会进入水生环境，对非靶标生物造成有害影响，并引发鲜为人知的生物紊乱。因此，为了扩大我们对烯唑醇对淡水鱼类生态毒性的认识，我们旨在确定烯唑醇的半致死浓度 (LC)，并使用淡水鱼罗非鱼作为模型系统，评估其不同毒性生物标志物的可能影响。使用概率分析方法，计算出鱼体中烯唑醇的 96 h LC 值为 4.5 mg/L。随后，将鱼暴露于两个亚致死浓度 (0.45 mg/L 为 1/10 LC 值和 0.9 mg/L 为 1/5 LC 值) 21 天。与对照组相比，鱼的鳃、肝和肾中的超氧化物歧化酶 (SOD) 和过氧化氢酶 (CAT) 活性显著降低。烯唑醇处理鱼的所有重要组织中的谷胱甘肽-S-转移酶 (GST) 和脂质过氧化 (LPO) 活性水平较高。鳃的组织学变化包括上皮细胞抬起、板层融合、肥大和上皮坏死。同时，肝脏显示出核固缩、空泡化、细胞水肿和肾小管坏死，肾小球缩小、空泡化和核固缩。根据浓度和时间依赖性，DNA 损伤显著增加，形成尾巴。因此，我们的研究证实，罗非鱼暴露于烯唑醇会引起负面的生物学后果，并揭示了这种杀菌剂对淡水鱼类物种的危险。我们相信，像我们这样的研究可以为修复/缓解烯唑醇引起的水生污染和保护淡水鱼类提供支持。
