贵州红枫湖地区水稻土多氯联苯和有机氯农药的残留

Residue of PCBs and OCPs in the Paddy Soil from Hongfeng Reservoir Area,Guizhou,China

调查了红枫湖周边水稻土的7种多氯联苯（PCBs）和13种有机氯农药（OCPs）的含量分布．结果显示，DDTs及其代谢产物、HCHs的异构体、异狄氏剂、七氯等有机氯农药及PCB28和PCB52在所有样品中均被检出．与国内外污染区相比，PCBs含量较低．研究区土壤中污染物的组成结果类似，PCBs以3—5氯取代的同属物为主，农药以DDTs为主．剖面土壤中∑PCBs含量范围为8．9—55．9ng／g，主要以3—5氯取代的PCBs为主，平均占PCBs总量的89％．∑DDTs含量为4．7—42．6ng／g，以p，p’-DDE，p，p＇-DDT为主．DDT／（DDD＋DDE）的比率表明红枫湖地区水稻田中DDTs的降解速率不同，暗示其环境条件的差异．α-HCH／γ-HCH为0．28-0．90，表明红枫湖地区水稻田中HCHs在环境中残留时间很长，经历了光解和生物作用等变化．PCBs对TEQ的贡献较低，为0．06—0．51pg／g．

Distributions of seven PCBs （polyehlorinated 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 α-HCH/γ-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. ∑ TEQ of PCB118 and PCB180 were 0.06 -0. 51 pg/g.