[Distribution characteristics and risk evaluation of organochlorine pesticides in soil from relocation areas of the Danjiangkou Reservoir].

Twenty-six surface soil samples collected in Danjiangkou Reservoir were analyzed for organochlorine pesticides (OCPs) residues by GC-MS. The distribution characteristics, compositions and origin of OCPs were discussed. Pollution level and potential ecological risks of OCPs were also evaluated. The results showed that the concentration rang of total OCPs in soil was nd-249.37 ng x g(-1) (with a mean of 24.82 ng x g(-1)). The recent occurrence levels in soil were nd-69.68 ng x g(-1) for HCHs and nd-104.53 ng x g for DDTs. DDTs concentrations in soil were higher than those of HCHs. The OCPs residues in soil were mainly originated from the early residues, atmospheric deposition and recent input of OCPs components. The correlation between OCPs contents and organic matter contents in soil was not significant, indicating that the contents of OCPs in soil were also affected by other factors. Compared with other soil samples from different regions, the contents of OCPs in soil of relocation areas of the Danjiangkou Reservoir were at medium-low level. The study suggested that the OCPs in soil of relocation areas of the Danjiangkou Reservoir are in a state of low danger, whereas OCPs still display risks locally in some places.