石家庄市公交站点尘土重金属的生物可给性及人体健康风险评估

利用PBET法研究石家庄市建设大街15个公交站点表层尘土中Cr、Mn、Cu、Zn、Cd和Pb的生物可给性,并采用US EPA人体健康风险模型对6种重金属的健康风险进行评价。结果表明：与河北省土壤元素背景值相比,Mn和Cr在各站点的的含量未超过背景值,Cu、Zn、Cd和Pb在各站点含量均超过背景值,其中Cd的富集程度最大。重金属溶解态量在胃和肠阶段差异较大,除在运河桥客运站Cr的溶解态量肠阶段大于胃阶段外,各重金属在所有站点溶解态量胃阶段均高于肠阶段。在所有站点中,Cu、Zn、Cd、Pb、Mn和Cr的生物可给性分别为40.57%~90.31%、45.67%~77.57%、61.03%~84.14%、49.05%~82.99%、59.46%~85.32%和11.36%~54.17%。儿童的非致癌风险商(HQ)和致癌风险商(CR)高于成人。6种重金属在各站点的HQ均小于１,在安全阈值之内。Cr和Cd在各站点的CR在1×10^-6~1×10^-4范围内,对儿童及成人存在一定致癌风险,但尚可接受；Pb在各站点的CR小于1×10^-6,对儿童及成人的致癌风险甚微,可忽略。

Bioaccessibility and health risk assessment of heavy metals in the dusts of bus stops in Shijiazhuang City

The Physiologically Based Extraction Test (PBET) method was used to study the bioaccessibility of Cr, Mn, Cu, Zn, Cd and Pb in the dusts of fifteen bus stops from the Jianshe Street in Shijiazhuang, and the US EPA human health risk model was applied to assess the health risks of six heavy metals. The results showed that the concentrations of Mn and Cr in all stops did not exceed the background values of soil in Hebei Province, the concentrations of Cu, Zn, Cd and Pb in all stops exceeded the background values. Among the four heavy metals, Cd had the largest degree of enrichment. The bioaccessible concentrations of these heavy metals in gastric and intestinal stages were obviously different. Except that the bioaccessible concentration of Cr in the intestinal stage was larger than that in the gastric stage at the Yunhe Bridge stop, the bioaccessible concentrations of six heavy metals in the gastric stage were higher than that in the intestinal stage at all stops. The bioaccessibility of Cu, Zn, Cd, Pb, Mn and Cr at all stops were 40.57%~90.31%, 45.67%~77.57%, 61.03%~84.14%, 49.05%~82.99%, 59.46%~85.32% and 11.36%~54.17%, respectively. The hazard quotients (HQ) and the carcinogenic risks (CR) of children were higher than that of adults. The HQ of six heavy metals in all stops were less than 1, within the safety threshold values. The CR of Cr and Cd ranged from 1×10^-6 to 1×10^-4, at an acceptable level. The CR of Pb were less than 1×10^-6 at various stops, which could be ignored.