氟虫双酰胺对蚯蚓的生化毒性与细胞毒性研究

双酰胺类杀虫剂已成为全世界第4大类最常用的杀虫剂,具有非常广阔的应用前景。然而,目前关于双酰胺类杀虫剂生态毒性评估方面的研究还比较少。为探究双酰胺类杀虫剂对非靶标生物的毒性作用,选取赤子爱胜蚓(Eisenia fetida)为受试生物,研究了典型双酰胺类杀虫剂氟虫双酰胺对非靶标动物蚯蚓的生化毒性和细胞毒性以及其在人工土和蚯蚓体内的浓度变化情况。结果表明,氟虫双酰胺在人工土壤中十分稳定,在整个暴露期间氟虫双酰胺的浓度变化不超过20%。氟虫双酰胺在蚯蚓体内的含量随染毒浓度的升高和暴露时间的推移而增加,呈明显的时间和剂量-效应关系;在染毒浓度为0.1和1.0 mg·kg-1的处理组中,氟虫双酰胺未对蚯蚓产生明显的氧化胁迫效应。在染毒浓度为5.0和10.0 mg·kg-1的处理组中,蚯蚓体内活性氧(ROS)含量显著高于其他处理组,过量的ROS诱导蚯蚓体内各种抗氧化酶活性发生异常变化,并在蚯蚓体内造成了脂质过氧化、蛋白质羰基化和DNA损伤。研究表明,当土壤中氟虫双酰胺的浓度为5.0和10.0 mg·kg-1时可能会对蚯蚓产生很高的风险。此外,彗星实验对氟虫双酰胺诱导的氧化胁迫较为敏感,可以作为敏感生物标志物对氟虫双酰胺造成的土壤污染进行预警。

Biochemical Toxicity and Cytotoxicity of Flubendiamide on Earthworms (Eisenia fetida)

Diamide insecticides have become the fourth most commonly used insecticides worldwide with broad application prospects. However, there are few data on the ecotoxicity of diamide insecticides. To explore the toxic effects of diamide insecticides on non-target organisms, the biochemical toxicity and cytotoxicity of typical diamide insecticides flubendiamide on earthworms (Eisenia fetida) were studied. At the same time, the effective concentrations of flubendiamide in artificial soil and earthworms were monitored during the entire exposure period. The results indicated that flubendiamide was stable in artificial soil as its concentrations changed no more than 20% during the entire exposure period. The content of flubendiamide in earthworms increased significantly as concentrations and exposure time increased, and induced obvious dose- and time-dependent effects. At low concentrations (0.1 and 1.0 mg kg^-1), flubendiamide had no obvious oxidative stress effects on earthworms. At high concentrations (5.0 and 10.0 mg kg^-1), the ROS levels were significantly higher than those in other treatments. The excess ROS levels induced abnormality in antioxidant enzyme activity, lipid oxidation, protein carbonyl and DNA damage in earthworms. The present results showed that flubendiamide may have a high risk for earthworms at 5.0 and 10.0 mg kg^-1. Additionally, comet assay is a sensitive biomarker for earthworms to monitor the damage induced by flubendiamide.