Spatial distribution, source analysis, and ecological risk assessment of DDTs in typical wetland surface soils of Poyang Lake

Dichlorodiphenyltrichloroethane (DDT) is a typical organic compound characterized by high bioaccumulability, toxicity, and persistence in the environment. To analyze the distribution and sources of DDTs in Poyang Lake, which is an important congregation site for migratory birds, the topsoils from five typical wetlands were sampled to evaluate the ecological threat posed by DDTs to organisms. The results show that as much as 56. 1 % of the DDTs detected in this study comprises dichlorodiphenyldichloroethylene (DDE), the aerobic metabolism of DDT. The o,p′-DDT:p,p′-DDT ratio was higher than 0. 2, which suggests that there was fresh influx of DDT from the pesticide. These results indicate that DDE was the main component among the metabolisms of DDTs and that the usage of dicofol might introduce DDT into the environment of Lake Poyang in a stealth form. However, an ecological risk assessment shows that the DDTs content in this region poses a low ecological risk.