The Degradation Of Endosulfan In Constructed Wetland And Its Interaction With Soil Microcosm

Endosulfan is one of the few organic chlorine insecticides that are still in use in many developing countries. It has medium toxicity to fish and aquatic invertebrates. In this study, we added different concentrations of endosulfan to a series of soil samples collected from Baihua Park in Jinan, Shandong Province, China and analyzed the effects of exogenous endosulfan on microbial community by monitoring the changes of microbe-specific phospholipid fatty acid (PLFA), residual endosulfan and its metabolites, including endosulfan sulfate, endosulfan lactone and endosulfan diol during a9days period of incubation. Our results showed that endosulfan reduced fungi instead of bacteria biomass by47%after9days. In addition, we found that endosulfan can be degraded in either natural soil (NE) or strepolin soil (SSE) as well as sterile soil (SE) with a decreasing rate by8.62%,5.51%and2.47%, respectively. Further analysis of the endosulfan metabolites in NE and SSE, we found that the amount of endosulfan sulfate (ES) significantly increased and that of endosulfan lactone (EL) slightly decreased in both soil after9days, whereas that of endosulfan diol (ED) increased in NE and decreased in SSE. Taken together, our data demonstrated that fungi and bacteria responded differently to exogeous endosulfan, in a way that bacteria can promote the formation of endosulfan diol during endosulfan degradation. On the other hand, the rule of degradation of endosulfan and its metabolites in constracted wetlands was studied in our research, and it was found that endosulfan could be absorbed fast at first and degraded slowly and saparatedly in water and sendiments. The half life of endosulfan was shorter than it in soil for the complexity of wetlands. Weeds could not degrade endosulfan obviously but they could affect the rhizosphere sendiments, where endosulfan degraded faster than in nomal sendiments.