内蒙古农牧业区土壤中有机氯农药的分布特征及健康风险评估

为研究内蒙古农牧业区土壤中有机氯农药(OCPs)的残留水平、分布特征、来源和健康风险,在研究区域采集216份表层土壤样品,利用气相色谱法(GC-ECD)对其中21种OCPs残留量进行了检测和相关分析。结果表明,内蒙古农业区和牧业区土壤中OCPs残留量范围(平均值)分别为0.64~102 ng·g~(-1)(26.3 ng·g~(-1))和0.18~23.8 ng·g~(-1)(5.81 ng·g~(-1))。六六六(HCHs)和滴滴涕(DDTs)是构成农牧业区土壤OCPs污染的主要成分,其异构体检出率范围为89.1%~100%,两者残留量均符合我国现行土壤环境质量标准(GB 15618—1995)一级指标,与国内其他地区土壤OCPs污染相比,研究区域土壤中OCPs污染处于较低水平。来源分析表明,农业区HCHs主要源于林丹使用和少量工业HCHs输入,DDTs可能与三氯杀螨醇输入有关;牧业区OCPs主要来自历史残留和大气沉降,不同植被类型土壤中,OCPs、HCHs和DDTs残留量最高的土壤类型均为蔬菜地、西瓜地和大豆地。风险评估结果显示,农牧业区土壤中OCPs的综合致癌风险值和综合非致癌危害商均在可接受范围内,对当地人群基本不构成致癌威胁和健康危害。

Distribution characteristics and health risk assessment of organochlorine pesticides in surface soil from the major farming and animal husbandry districts in Inner Mongolia

216 surface soil samples were collected from the major farming and animal husbandry districts in Inner Mongolia. 21 kinds of organochlorine pesticides(OCPs) in soil were analyzed by a Ni electron capture detector(GC-ECD) to investigate the residues level, distribution characteristics, sources and potential health risks of these compounds in the study region. The results showed that OCPs residues in both farming and animal husbandry district soil ranged 0.64~102 ng·g^-1(mean 26.3 ng·g^-1) and 0.18~23.8 ng·g^-1(mean 5.81 ng·g^-1), respectively. The detection ratio of HCHs and DDTs''s isomers ranged between 89.1% and 100%, which were considered to be the dominant OCPs in the research region, and their concentrations accorded with the first class levels of the environmental quality standard for soils(GB 15618-1995). Compared with other regions, the OCPs pollution in this study region stayed at a lower level. In addition, source analysis indicated that lindane, a small number of industrial HCHs and dicofol might be used in the farming district. However, for the animal husbandry district, the early residues and atmospheric deposition of OCPs were the main cause of soil pollution. The higher residue level of OCPs, HCHs and DDTs in different types of lands occurred in vegetable land, watermelon patch and soybean field. The health risk assessment suggested that OCPs residues in the survey areas do not pose a health threat to the local residents.