Bioremediation of β-cypermethrin and 3-phenoxybenzoic acid in soils

Abstract

β-cypermethrin (β-CP) is one of the most frequently and widely used kind of insecticides. Increasing use of β-CP has posed potential adverse effects on the environment; therefore, it is critically necessary to develop remediation strategies to remove β-CP from the environment. In this study, bioremediation efficiency of β-CP contaminated soils was assessed based on the results of laboratory experiment. The selected bacterium Achromobacter sp. strain P-01 was used to degrade β-CP and its major metabolite 3-phenoxybenzoic acid (3-PBA) in different soils. Studies on bioremediation in sterilized soil showed that strain P-01 exhibited efficient degradation of β-CP and 3-PBA (both 50 mg·kg-1) with a rate constant of 0.1857 and 0.1084 day-1, respectively. The degradation process followed the first-order kinetics and the half-life (T1/2) for β-CP and 3-PBA was 3.7 and 6.4 days, respectively. Studies on bioremediation in non-sterilized soil showed that degradation rates were 90.4% and 70.6% for β-CP and 3-PBA within 10 days after strain P-01 introduction, which was characterized by a constant of 0.3334 and 0.1341 day-1, respectively. Comparing with the control without inoculum, T1/2 for β-CP and 3-PBA reduced by 21.6-154.8 days. These results indicated that strain P-01 may have potential for use in bioremediation of β-CP contaminated environment.