岩溶地下水水体中有机氯农药和多氯联苯的残留特征及健康风险评价

采用气相色谱-微池电子捕获检测器（GC-μECD）测定南山老龙洞岩溶地下水水体中有机氯农药（OCPs）和多氯联苯（PCBs）残留量，并探究了OCPs和PCBs的浓度、分布和来源等残留特征.结果表明，OCPs总浓度范围为34.8~623.2 ng·L^-1，均值为215.6 ng·L^-1，其中，HCHs、DDTs和其它类OCPs总浓度范围分别为8.2~23.6、4.5~363.7和22.2~235.9 ng·L^-1，均值分别为15.9、104.5和95.3 ng·L^-1；PCBs总浓度范围为6.0~40.7 ng·L^-1，均值为16.8 ng·L^-1.总体而言，OCPs和PCBs污染处于中上水平；多重比较结果显示部分OCPs和PCBs平均浓度具有统计学意义上的显著差异.研究区各采样点水体中污染水平差异较大，但OCPs和PCBs的季节分布相对均匀.源解析表明，HCHs源于周围环境中林丹的输入；DDTs源于近期工业DDT的非法使用；其它类OCPs源于大气沉降和农业活动输入；PCBs来源既有历史残留，又有企业排污活动；Pearson相关分析表明部分有机卤素污染物具有同源性，或有类似的来源和分解机制.结合健康风险评价模型，研究区饮用水不会对人体健康产生明显危害，但儿童对污染物的敏感性高于成人.

Residual Characteristics and Health Assessment Analysis of OCPs and PCBs in Karst Groundwater

Residual levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in karst groundwater in Nanshan Laolongdong were measured using a gas chromatograph equipped with a micro-⁶³Ni electron capture detector to determine the residual characteristics including concentration, distribution, and source of OCPs and PCBs. Results revealed that the total concentration range of OCPs was 34.8-623.2 ng·L^-1, and the mean value was 215.6 ng·L^-1, among which the total concentration ranges of HCHs, DDTs, and other OCPs were 8.2-23.6, 4.5-363.7, and 22.2-235.9 ng·L^-1, respectively, and the mean values were 15.9, 104.5, and 95.3 ng·L^-1; the total concentration range of PCBs was 6.0-40.7 ng·L^-1, and the mean value was 16.8 ng·L^-1. Overall, the pollution of OCPs and PCBs was above average; the results of multiple comparisons revealed that statistically significant differences occurred in the concentration of some OCPs and PCBs. The pollution levels in the water of each sampling point in the study area were quite different; however, the seasonal distribution of OCPs and PCBs was relatively uniform. Source analyses revealed that HCHs'' source was the input of lindane in the surrounding environment, DDTs recently originated from illegal use of industrial DDT, other OCPs originated from atmospheric deposition and agricultural input, and PCBs'' sources included both historical remains and enterprise production processes. The results of Pearson correlation analyses revealed that some organo-halogen pollutants were homologous or had similar sources and decomposition mechanisms. According to health risk assessment model, drinking water in the study area would not cause obvious harm to human health, but children were more sensitive to pollutants than adults.