A Bioremediation and Soil Fertility Study: Effects of Vermiremediation on Soil Contaminated by Chlorpyrifos

Abstract

Although the broad-spectrum pesticide chlorpyrifos (CP) was banned in many developed countries, it is still widely used in developing countries. Its residues persist in the environment for unpredictable times. CP is toxic to various non-target organisms and humans and inhibits soil enzyme activity and bacterial and fungal abundance. This paper aimed to evaluate the effect of vermiremediation on soil chlorpyrifos content and soil fertility. The application of Eisenia fetida or vermicompost was studied in terms of soil chlorpyrifos concentration, microbial biomass content, and enzymatic activities in a 120-day trial. Pesticide application rates were 0, 25, and 50 ppm. The CP did not affect the earthworm survival rate at the tested doses. The earthworms markedly increased microbial biomass carbon and the activity of β-glucosamminidase, while the vermicompost had a noticeably positive effect mainly on alkaline phosphatase activity. Finally, although the vermiremediation techniques studied did not perform a bioremediation activity, they proved effective in improving the biological fertility of the soil in the presence of high concentrations of chlorpyrifos.