Toxicological effects of soil contaminated with spirotetramat to the earthworm Eisenia fetida

• Multiple biomarkers were used to evaluate the toxic effects of spirotetramat on Eisenia fetida.
• There were potentially toxic effects of spirotetramat to E. fetida.
• Spirotetramat can induce DNA damage in E. fetida.
• The comet assay is a sensitive method for detecting DNA damage in earthworms.

The aim of this study was to evaluate the potential toxicity of spirotetramat to the earthworm Eisenia fetida in a natural soil environment. Many biochemical markers, viz., superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione S-transferase (GST), cellulase, and malondialdehyde (MDA) contents were measured after exposure to 0.25, 1.25, and 2.5 mg kg−1 for 2, 7, 14, 21, and 28 days. In addition, the comet assay was performed on earthworm coelomocytes to assess the level of genetic damage. The results demonstrate that the SOD activity and MDA content were significantly stimulated by the highest dose (2.5 mg kg−1) of spirotetramat for the entire period of exposure. The activities of CAT and POD increased significantly by 2 d and 21 d, respectively, but the activities of both were significantly inhibited after prolonged exposure (28 d). After an initial increase on the 2nd day, the cellulase activity in the high-dose treatment group was significantly inhibited for the entire remaining exposure period. The comet assay results demonstrate that spirotetramat (⩽2.5 mg kg−1) can induce low and intermediate degrees of DNA damage in earthworm coelomocytes. The results indicate that spirotetramat may pose potential biochemical and genetic toxicity to earthworms (E. fetida), and this information is helpful for understanding the ecological toxicity of spirotetramat on soil invertebrate organisms.