太原市土壤六六六和滴滴涕的暴露格局及健康风险

为研究六六六(HCHs)和滴滴涕(DDTs)在太原市不同功能区土壤中的暴露格局、来源以及对周围人群的健康风险,在太原市化工区、灌区、矿区、生态区周边荒地土壤中进行采样,分析测定了土壤中HCHs和DDTs含量,根据太原市人群实际情况的暴露参数和USEPA的部分参数,对土壤HCHs和DDTs的健康风险进行评价。结果表明:1)太原市表层土壤中HCHs的平均含量大小依次为化工区>灌区>矿区>生态区;DDTs平均含量的大小依次为化工区>灌区>矿区>生态区,仅6%的HCHs和3%的DDTs和的平均残留水平均高于我国土壤质量标准一级标准,但均不超过二级标准值;2)土壤中HCHs残留主要源于历史上林丹的使用,DDTs残留则来源于历史和新污染源的共同影响;3)太原市表层土壤HCHs和DDTs致癌风险大小为化工园区>矿区>灌区>生态区。非致癌风险大小为化工区>矿区>灌区>生态区。3种暴露途径的在不同功能区的健康风险贡献率大小均为经口摄入>呼吸吸入>皮肤接触;综合来看太原市表层土壤中的HCHs和DDTs并未对人类造成非致癌风险,但有一定的致癌风险。本文的研究结果可为太原市土壤质量评价和环境污染防治提供科学指导,并对太原市人群的健康风险防治提供依据。

The Exposure Pattern and Health Risk of HCHs and DDTs in Soils of Taiyuan

The exposure patterns, sources and human health risks of HCHs and DDTs were evaluated in this study in different functional zones of Taiyuan. The soil samples were separately collected from industrial, irrigated zone, mining zone and ecological zone in Taiyuan and the contents of HCHs and DDTs in the soil samples were detected. In accordance with the actual population exposure indexes in Taiyuan and the parts of USEPA indexes, the population health risks of soil contaminated HCHs and DDTs in Taiyuan were investigated. The estimated median content of soil contaminated HCHs was followed by this order of industrial zone> mining zone> irrigation zone>ecological zone, and the estimated median content of soil contaminated DDTs was followed by this order of industrial zone> mining zone>irrigation zone> ecological zone. The median residual levels of HCHs and DDTs in each functional zone were respectively 6% and 3%, which values were higher than the first-order threshold value specified in Chinese Soil Quality Standard, but lower than the secondary standard value. The soil residual levels of HCHs and DDTs are individually mainly due to the utilizations of lindane and the combination from the previous and new compounds utilizations. Interestingly, both the estimated carcinogenic risk and non-carcinogenic risk of soil contaminated HCHs and DDTs were followed by the orders of industrial zone> mining zone> irrigation zone> ecological zone. The contribution rates of the three exposure routes to health risk in different functional zones were all followed by the orders of oral ingestion> inhalation of airborne> dermal contact. Overall, non-carcinogenic population health risk caused by the soil contaminated HCHs and DDTs in Taiyuan could be ignored, however, carcinogenic population health risk caused by soil contaminated HCHs in all functional zones and DDTs in industrial zone should be obviously determinated. This study could provide both the directions for soil quality assessment and environment pollution prevention, and a scientific basis for population health risk prevention in Taiyuan.