Pollution characteristics and health risk assessment of heavy metals in street dusts from different functional areas in Beijing, China.

Street dusts from Heavy Density Traffic Area, Residential Area, Educational Area and Tourism Area in Beijing, China, were collected to study the distribution, accumulation and health risk assessment of heavy metals. Cr, Cu, Zn, Cd and Pb concentrations were in higher concentrations in these four locations than in the local soil background. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Beijing were generally at moderate or low levels. Ni, Cu, Zn and Pb concentrations in the Tourism Area were the highest among four different areas in Beijing. A pollution assessment by Geoaccumulation Index showed that the pollution level for the heavy metals is in the following order: Cd>Pb>Zn>Cu>Cr>Ni. The Cd levels can be considered "heavily contaminated" status. The health risk assessment model that was employed to calculate human exposure indicated that both non-carcinogenic and carcinogenic risks of selected metals in street dusts were generally in the low range, except for the carcinogenic risk from Cr for children.