[Study on removal rule of endosulfan in surface flow constructed wetland]

Endosulfan is a kind of widespread organochlorine pollutant in the environment. The removal rule of three different concentrations of endosulfan in different parts of a surface flow constructed wetland was investigated. The concentrations of endosulfan in water, plants, non-rhizosphere sediments and rhizosphere sediments were determined by the Soxhlet extraction-GC method. The results showed that constructed wetland was efficient in endosulfan removal. The removal rate of endousulfan in water, non-rhizosphere sediments and rhizosphere sediments was 87.9%, 63.0% and 70.9%, respectively. In this system, alpha-endosulfan was removed faster than beta-endosulfan and the metabolite accumulated was mainly endosulfan sulfate. The adsorption of sediments played an important role in the removal of endosulfan. About 80.0% of endosulfan in water could be adsorbed by sediments within three days. The removal rate of endosulfan could be enhanced by plants. Because of the effect of plants, the average removal rate of endosulfan in rhizosphere sediments was 7.9% higher than that in non-rhizosphere sediments.