Carbaryl and endosulfan induced alteration of biochemical markers in soil organisms, Eisenia fetida

Background and Objective: Pesticides are chemicals designed and used to destroy and control pests that affect crops, thereby ensuring food security. Only a small fraction of the sprayed pesticides reach the intended pests, the rest find their way into the environment where they adversely affect non-target organisms. The toxicological effects of pesticide contaminated soil was assessed on selected biomarkers in Eisenia fetida to assess whether the pesticides under study have prooxidant properties which negatively impacts non-target soil organisms.

Materials and Methods: Soil samples were collected from a private farm and a control site. The soils were analyzed for carbaryl and endosulfan. Earthworms were exposed to soils for up to 21 days. The earthworms were then analyzed for antioxidant enzyme activities, reduced glutathione and malondialdehyde levels. Two-way Analysis of Variance (ANOVA) in Tukey’s multiple comparison test was used to show statistical differences.

Results: Carbaryl and endosulfan residues were detected in the soil from the farm. Enhanced activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and DT-diaphorase were observed. Malondialdehyde content was enhanced in earthworms exposed to the soil from the farm compared to malondialdehyde levels in earthworms exposed to the control soil. The activation of antioxidant and xenobiotic enzymes were a result of pollutants in the soil which included carbaryl and endosulfan. Increased malondialdehyde content indicated oxidative stress in the earthworms that were exposed to pollutant-contaminated soils, probably caused by the insecticides carbaryl and endosulfan present in the soil.

Conclusion: The study highlighted the need of continued monitoring of pollutants in soil to safeguard the health of soil organisms.