Bioremediation of Endosulfan Contaminated Soil by using Microbial Consortia in the Field

Abstract

Objectives : The use of risky and persistent organochlorine pesticides was prohibited, but is still detected in many agricultural lands. In this study, Phanerochaete chrysosporium Y-2 (KCCM-10725P) and Streptomyces sp. MJM14747 (KACC 81078BP), which were finally selected among various candidate microorganisms, were applied to field soil and estimated the endosulfan removal rate.Methods : The field testing sites were set to an area of 3 m × 3 m, respectively. A 35% endosulfan emulsion was sprayed on both sites so that the final concentration was about 20 µg/g. Thereafter, 12 kg of original sawdust and 12 kg of sawdust loaded with microbial consortia were mixed at each of the two sites. During the test period for a total of 100 days, samples were taken every 30 days. Soil samples were extracted according to the QuEChERS AOAC method and analyzed by gas chromatography.Results and Discussion : The concentrations immediately after endosulfan emulsion treatment at both sites were detected as 21.2 µg/g and 21.9 µg/g, respectively. The removal rate of endosulfan at the site without microbial consortia treatment (Control) was about 21.9% until the 30th day, and 54.4% on the 100th day. On the other hand, the endosulfan removal rate on the 100th day of the site treated with microbial consortia was 89.5%, which was 1.6 times higher than that of the control site. On the 30th day, the removal rate was 56.8%, and the rate of degradation of endosulfan increased thereafter. Among the major components of endosulfan, the removal rate of α-endosulfan was higher than that of β-endosulfan. After 100 days, the removal rates of α-endosulfan and β-endosulfan were 98.0% and 83.5%, respectively.Conclusions : Streptomyces sp. MJM14747 showed good degradation ability in the presence of endosulfan at a high concentration of around 100 µg/g. Moreover, Phanerochaete chrysosporium Y-2 has a good performance in the removal of β-endosulfan, which is slow degrading components of endosulfan. Microbial consortia are expected to be applied not only to domestic and foreign agricultural land but also to overall bioremediation projects.