Bioremediation of soil contaminated with carbofuran under saturated condition : a soil column study

Abstract

In the present study, the disturbed soil columns were used as a basic model to simulate the movement of carbofuran in rice field soil under the saturated condition. Bioremediation technique i.e., bioaugmentation and biostimulation were applied to enhance the degradation of carbofuran in soil and prevent the movement of carbofuran to groundwater. The initial carbofuran concentration in soil was 10 mg kg-1soil. The specific carbofuran degrader, Burkholderia sp. PCL3, in free and immobilized cells forms were used as seed inocula in bioaugmentation treatments. Rice straw was used as organic amendment in biostimulation treatments. In abiotic control and in the treatment with only indigenous microorganisms, the mass recovery percentage of carbofuran in the effluent was 52.07 and 22.54%, respectively. The application of bioaugmentation or biostimulation alone significantly enhanced carbofuran degradation and reduced the movement of carbofuran in soil as indicated by a low mass recovery in the effluent in the range of 14.62-15.54%. In the soil column with bioaugmentation together with biostimulation treatments, the mass recovery in the effluent were in the range of 22.08-22.57%. Number of carbofuran degraders in the effluent from each column was in the ranges of 105-108 CFU ml-1. Number of carbofuran degraders 104-108 CFU soil-1was not markedly different, among soil sections at the end of column operation. Results suggested that the bioremediation technique could be applied to enhance the degradation of carbofuran in soil and prevent the movement of carbofuran to groundwater especially in the area where carbofuran have been extensively used.