中文摘要：

以天津城市道路灰尘重金属为研究对象,对天津市中心城区内环（12个采样点）、内环-中环（39个采样点）、中环以外（93个采样点）3个区域进行采样分析,为评价存在于沉积灰尘中的重金属因子Cd、Cr、Cu、Ni和Pb的污染水平,运用地积累指数Igeo法对道路灰尘重金属进行污染评价,运用潜在生态风险指数法对道路灰尘重金属进行生态风险评价。研究结果表明：（1）在污染水平方面,天津城市道路灰尘中重金属Cd、Cr、Cu、Ni和Pb的地积累污染指数分别为2.78、-0.06、1.22、-0.20和0.96,污染程度等级分别为Ⅳ（中度污染）、Ⅰ（无污染）、Ⅲ（偏中度污染）、Ⅰ（无污染）、Ⅱ（轻度污染）,其中重金属Cd污染程度最为严重。（2）在生态危害方面,5种重金属潜在生态风险程度顺序为Cd垌Cu〉Pb〉Ni〉Cr,其中重金属Cr、Ni、Pb、Cu的潜在生态风险指数分别为2.88、6.51、14.64、17.47,生态风险程度等级均为Ⅰ,生态危害均处于较低水平;重金属Cd的潜在生态风险指数为330,生态风险程度等级为Ⅴ,生态危害水平极高。天津市重金属污染的综合潜在生态风险指数为371.50,其生态危害程度处于较高水平。

英文摘要：

This paper took the heavy metals in urban street dust of Tianjin as the research object. Dust samples were collected from 144 sites of urban streets in Tianjin for the heavy metals （Cd, Cr, Cu, Ni and Pb） pollution study. The pollution degree was assessed by the geo-accumulation index, and the risk was assessed by the potential ecological risk index. The results show that the geo-accumulation index of Cd, Cr, Cu; Ni and Pb was 2.78, -0.06, 1.22, -0.20 and 0.96, which was generally at medium pollution level（IV）, non-pollution level（ I ）, partial medium pollution level（ HI ）, non-pollution level（ I ）, and slight pollution level （ 11 ） respectively. The pollution degree of Cd was the most serious. The risk order of heavy metals was Cd〉Cu〉Pb〉Ni〉Cr. The potential ecological risk index of Cr, Ni, Pb and Cu was 2.88, 6.51, 14.64 and 17.47 respectively, which revealed that the potential ecological risk of these heavy metals was at low level （ I ）. The potential ecological risk index of Cd was 330, at the extremely high level （V）. Potential ecological risk of total heavy metals pollution was heavy with the comprehensive potential ecological risk index of 371.50.