西安市文教区地表粉尘中Pb,Cd及其同位素污染特征和风险评价

Characteristics and Risk Evaluation of Pollution by Pb,Cd and Their Isotopes from Surface Dust in Culture and Education District in Xi′an City

地表粉尘中重金属对人体的健康有着重要影响。采用电感耦合等离子体原子发射光谱—质谱法(ICP—MS)对西安市文教区地表粉尘中的重金属Pb和Cd的季节含量进行了测定。采用地质累积指数法分析了重金属的污染特征,并采用健康风险评价法对各污染源进行了风险评价。结果表明,西安市文教区地表粉尘中Pb和Cd的含量大部分超过陕西省土壤背景值,地质累积指数范围大部分小于1,属于无污染或轻度污染。而冬季地表粉尘中重金属污染高于其它季节,其中冬季地表粉尘中重金属Pb的区域受污染程度顺序为:东郊>西郊>北郊≈南郊,Cd的含量区域差别顺序为:东郊>南郊>北郊>西郊,在重金属Pb和Cd的3种同位素中,207Pb和112 Cd的含量最高。Pb和Cd的日均暴露剂量最大的途径是经口误食,其中镉对人体健康的危害远高于铅。

Based on the measurement of the heavy metal Pb and Cd seasonal content in the surface dust by ICP--MS in the culture and education district in Xi＇an City, the article analyzed its pollution characteristics using the classification of geological cumulative pollution index, evaluated the health risks with the health risk evaluation method. The result showed that the content of the heavy metal Pb and Cd content in the sur- face dust exceeded its soil background value of the Shaanxi Province and most of the geological cumulative in- dex was smaller than 1, which belonged to the slight pollution while the pollution in winter was more serious than the other seasons, of which the contents of the metal Pb and Cd were higher in the eastern suburb while equal in the rest southern, western and northern suburbs. Among three isotopes of Pb and Cd, the content of 207pb and 112Cd were the highest. The average daily exposure intake of Pb and Cd was through mouth by mistake, and intake of Cd was more harmful than Pb.