DNA damage and effects on antioxidative enzymes in earthworm (Eisenia fetida) induced by flumorph

Flumorph is an Oomycete fungicide, which is used extensively as an effective fungicide in vegetables and fruits, but little is known about its effect on nontarget soil organisms. In the present study, biochemical responses including changes in the activity of antioxidative enzymes catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), malondialdehyde (MDA), and DNA damage induced by flumorph were investigated in earthworms (Eisenis fetida). The CAT concentrations were stimulated at 5.0 mg kg(-1) over 28 days and inhibited at 10 and 20 mg kg(-1), except 10 mg kg(-1) on days 21 and 28 compared with the controls. The overall SOD activities were inhibited except 5 mg kg(-1) on day 28 and 10 mg kg(-1) on days 7 and 14. Meanwhile, the GST activities were stimulated on day 7 and decreased on the other days in summary. The MDA activities were increased notably at 5, 10, and 20 mg kg(-1) after 14 days. Clear dose-dependent DNA damage to Eisenia fetida was observed by olive tail moments in comet assay compared with controls. The results demonstrate that flumorph induces oxidative stress and DNA damage to earthworms, and the effects may be the important mechanisms of its toxicity.