Biodegradation And Detoxification Of Endosulfan In Endosulfan-contaminated Soil By JBW4

JBW4which was Alcaligenes Alcaligenes strains was isolated from wastewaterand sludge from a pesticide plant by our laboratory. In order to understand the effect of JBW4in repair of endosulfan contaminated soil, five research sections have been investigated suchas the change of the degradation rates and the half-life, the colonization of JBW4inendosulfan contaminated soil, genotoxicity changes of endosulfan before and afterdegradation, the soil enzyme activity changes after adding JBW4and the degradation product.The results have been obtained as follows:1. Pesticide residue experiment was used to study the degradation of endosulfan in soil.This article set four different soil treatment, and samples were collected at0,3,7,14,21,28,35,49,63,77d to extract the residual endosulfan for detection by gas chromatography.Results showed JBW4had good ability in removal of endosulfan in soil. Thedegradation rates of α-endosulfan in SE, NE, SEJ, NEJ were, respectively,50.5%,64.5%,75.8%,87%.β-endosulfan were40.9%,54.5%,58.5%,69.5%. The half-life ofα-endosulfan inSE, NE, SEJ, NEJ were87.7,53.3,37.9,25.9d. β-endosulfan were192.5,70.7,64.2,47.5d.The rates of degradation of endosulfan in soil treated by JBW4were significantly higher thanthat did not increase JBW4, and the half-life showed a significant reduction.2. The method of PCR-DGGE has been applied to investigate the establishment ofJBW4strain in the soil. This study investigated the colonization of JBW4strains in3,5,7d.Through the control bar with DNA electrophoresis, identify target bands of JBW4. If there isthe target band in the electrophoresis, it showed that JBW4successful colonization in soil.The test results indicated that JBW4could successfully colonization in the natural soil andsterile soil.3. In this paper, we choose Eisenia foetida as experimental material. Experimental soilsamples (water: soil5:1) were made mud, vibration training, test substance solution wereaccepted by centrifuge. Through exposure of the filter paper method, earthworms degree ofDNA damage were detected by comet assay. The evaluation index was used to determine thedegradation changes before and after the soil genotoxicity.3d of ntatural soil and natural soil +degradation bacteria Olive tail moment were, respectively,64.3and55.2μm, the first77dof natural soil and natural soil+degrading bacteria Olive tail distances were26.6and7.4μm.Along with the degradation of endosulfan in soil the genetic toxicity of the soil is graduallyreduced. The genetic toxicity of the soil significantly reduced after inoculation JBW4strain.4. This article also determines the enzyme activities in soil to study the change ofecotoxicity after inoculating JBW4strains into the soil. In this study, soil urease anddehydrogenase were choose as index to measure the change of the soil ecotoxicity before andafter the endosulfan was degradated. The results show that soil urease and dehydrogenase bythe inhibitory state has been eased significantly after inoculating JBW4strain to contaminatedsoil, to the latter even more than the activity in the blank soil, which indicates that soilecotoxicity significantly reduced with the degradation of endosulfan in soil.5. Analysis of the extracted metabolites. In our research, endosulfan metabolites wereidentified in the test culture medium by GC-MS. Endosulfan lactone and Endosulfan etherwas detected as the major intermediate metabolites,the result suggest that strain JBW4mightdegrade endosulfan by a hydrolysis pathway.The pathway of endosulfan degradation：endosulfan→Endosulfan diol→Endosulfan lactone.