北京地区地表水中OCPs和PCBs的污染分析

在夏、冬两季对北京地区密云，潮白河，玉渊潭和通惠河等地表水中17种有机氯农药（OCPs）和84种多氯联苯（PCBs）的含量进行了分析及来源解析.实验结果表明，OCPs总量在7.86～53.1ng/L之间，平均值为（16.9±14.6）ng/L.PCBs总量在2.99～32.7ng/L之间，平均浓度为（10.9±10.4）ng/L.HCHs，硫丹，DDTs和HCB是主要的OCPs污染物，其含量分别为（13.9±11.5）ng/L，（2.20±2.01）ng/L，（0.63±1.51）ng/L和（0.12±0.14）ng/L.α-HCH/γ-HCH平均比值为1.53，小于工业HCH中比值4～7，表明北京地区地表水中存在林丹的使用.而DDT/（DDD+DDE）比值<1.22，表明北京地区并无新的DDTs污染源输入环境.PCBs以低氯代联苯为主，其中二氯，三氯，四氯和五氯联苯总和占∑₈₄PCBs总量的79.2%.北京地区地表水中不同氯取代数PCBs组成与我国历史PCB产品组成相符，均以低氯代联苯为主，表明北京地区地表水中PCBs污染来源为历史使用.相比于国内其他区域水质而言，北京地区地表水OCPs和PCBs污染水平较低.

The study of organochlorine pesticides and polychlorinated biphenyls in surface water around Beijing

The concentrations and sources of 17organochlorine pesticides (OCPs) and 84polychlorinated biphenyls (PCBs) were analyzed in the surface water of Miyun, Chaobai River, Yuyuan Lake and Tonghui River in Beijing during summer and winter. The concentrations of 17OCPs were in the range of 7.86~53.1ng/L, with an average of (16.9±14.6) ng/L. The concentrations of 84PCBs were in the range of 2.99~32.7ng/L, with an average of (10.9±10.4) ng/L. The major compositions of OCPs were HCHs, endosulfan, DDTs and HCB with the concentrations of (13.9±11.5) ng/L, (2.20±2.01) ng/L, (0.63±1.51) ng/L and (0.12±0.14) ng/L, respectively. The average ratio of α-HCH/γ-HCH was 1.53 indicating the application of lindane in Beijing. In the meanwhile, the ratio of DDT/(DDD+DDE) was <1.22 which lower than 4~7 in technical HCHs, suggesting historical inputs of DDTs into the environment in the study area. The concentrations of different homologues of PCBs were dominated by Di-CBs, Tri-CBs, Tetra-CBs and Penta-CBs, accounting for 79.2% of ∑₈₄PCBs. The domination by lower chlorinated CBs was similar to the historical products of China, indicating the residual of PCBs in surface water in Beijing resulting from historical usage. Comparing to the surface water in other areas in China, the contamination levels of OCPs and PCBs in surface water in Beijing were relatively low.