Long-term toxic effects of deltamethrin and fenvalerante in soil

•The distinct reproduction toxicity of low concentration pyrethroids in soil was demonstrated.•The significant response of CYP3A4 enzyme activity to pyrethroids in worms was found.•The increased toxicity of pyrethroids was contrary with its degradation rate in soil.•Based on our data the formation of toxic metabolites of pyrethroids in soil was assumed.•The toxicity response of individual pyrethroids is environmental matrix correlated. In this study, the long-term toxic effects of pyrethroids on the earthworm Eisenia fetida were evaluated. Earthworms were exposed to moist filter paper and soil for 14 days to evaluate the survival, exposed to soil for 56 days to assess the reproductive success and for 28 days to identify the cytotoxicity. Results showed that the earthworm survival rate decreased with increasing the concentration of either deltamethrin or fenvalerate in both filter paper test and soil test. No worms survived at 602.15μgcm−2 of deltamethrin and 0.86μgcm−2 of fenvalerate in the filter paper test, however 100–125mgkg−1 of both chemicals resulted in the maximum mortality of 90% in the soil test. The CYP3A4 enzyme activity responded significantly to deltamethrin and fenvalerante in soil at low concentration levels, however, the toxicity response of worms under the long-term exposure conflicted with the degradation of deltamethrin and fenvalerate in soil, indicating the possible formation of more toxic pyrethroid metabolites. This study gave an insight into the toxicological effects profile of pyrethroids for a better risk assessment of pyrethroids deltamethrin and fenvalerante in soil.