Toxicity effect of dichlorvos on loach ( Misgurnus anguillicaudatus ) assessed by micronucleus test,hepatase activity analysis and comet assay

Abstract

Pesticides and other chemicals at environmental concentrations often have detrimental effects. Many aquatic species are particularly threatened because of their susceptibility and also because water environment are often polluted. This study preliminarily evaluated the toxicity effect of dichlorvos (DDVP) on loach (Misgurnus anguillicaudatus) using the methods of micronucleus (MN) test, hepatase activity and comet assay. The tested results showed that indeed very little DDVP had strong toxicity effect on loach and its 50% lethal concentration (LC₅₀) at 24 h, 48 h and 96 h was 8.38 μg l⁻¹, 7.168 μg l⁻¹ and 6.411 μg l⁻¹, respectively; The glutamic-pyruvic transaminase (GPT) and glutamic–oxalacetic transaminase (GOT) activity of loach liver decreased; meanwhile, the GPT and GOT activity of loach serum, the MN rate (‰) and three comet parameters of tested fish increased with the increase in the treatment concentration and treatment time of DDVP, and there was significant difference between control group and each treatment group (p < 0.05). These results suggested that DDVP residues might become toxic chemical contaminant in environment and would threaten aquatic and other organisms.