Evaluating subchronic toxicity of fluoxastrobin using earthworms (Eisenia fetida)

Potential toxicity to soil organisms by fluoxastrobin, a new strobilurin-type fungicide has drawn increasing attention. Thus, the present study investigated the subchronic toxicity induced by exposure to several concentrations (0, 0.1, 1.0, and 2.5 mg kg^-1) of fluoxastrobin to earthworms on days 7, 14, 21, and 28. Biochemical indicators (e.g., reactive oxygen species (ROS) content, activities of antioxidase and detoxifying enzymes (superoxide dismutase, catalase, and glutathione S-transferase), lipid peroxidation (malonaldehyde) and degree of DNA damage) were measured. No earthworm deaths were observed during the entire experimental period. For ROS and malonaldehyde, the bioassay values of the three doses reached a maximum on day 21 and then decreased. For superoxide dismutase and glutathione S-transferase, the values increased with the exposure doses of 0.1 and 1.0 mg kg^-1 and then decreased. In contrast, the values for catalase were lower on days 7, 14, and 28 and greater on day 21 compared to those of the controls. In addition, the comet assay was more sensitive than other biomarkers, and the degree of DNA damage was dose and time -dependent.