[Residue of PCBs and OCPs in the paddy soil from Hongfeng reservoir area, Guizhou, China].

: Distributions of seven PCBs (polychlorinated biphenyls) congeners and 13 OCPs (organochlorinated pesticides) were investigated in paddy soil section in Hongfeng reservoir area. The results showed that DDTs and its metabolized compounds, isomer of HCHs, Endrin, heptachlor, PCB 28 and PCB 52 were detected in all soil samples. Compared to the polluted area, the concentrations of PCBs were lower in study area, while the compositions of organic pollutants in soil samples were similar. The dominant compositions of PCBs and OCPs were tri-, tetra-, and penta-chlorinated PCB congeners and DDTs respectively. The proportion of tri-, tetra-and penta-CB was 89 percent. The contents of DDTs were between 4.7 ng/g and 42.6 ng/g and p, p'-DDE, p, p'-DDT were the major isomers. The ratios of DDT/ (DDD + DDE) showed that the rate of DDTs degradation and environment status were different. The range of alpha-HCH/gamma-HCH was 0.28 - 0.90, indicating that HCHs had stayed for long time in environment. By photolysis and microbial, the proportion of the HCHs isomers had changed in Hongfeng reservoir area. SigmaTEQ of PCB118 and PCB180 were 0.06 - 0.51 pg/g.