Heavy metals in street dust in Beijing, China: seasonal and spatial variations, pollution characteristics and health risk assessment

Abstract

Abstract Street dust samples were collected from industrial, residential, educational, commercial, and park areas in Beijing, China, during spring and winter to investigate the contents of heavy metals (Cr, Ni, Cu, Zn, Pb, As, Cd and Hg) and evaluate the source apportionment and degree of environmental pollution according to the geo-accumulation index, ecological indices, and human health risk assessment. The average contents of eight heavy metals (mg/kg) in spring are as follows: Cr (98.17), Ni (26.38), Cu (67.33), Zn (394.87), Pb (64.39), As (6.32), Cd (0.618), and Hg (0.207). In winter they are Cr (94.54), Ni (26.13), Cu (73.03), Zn (341.73), Pb(73.09), As (7.66), Cd (0.635), and Hg (0.279). The rank order of heavy metals concentrations in functional areas is IA (Industrial area) >CA(Commercial area) >EA(Educational area) >RA(Residential area) >PA(Park area). The source apportionment analysis indicates that heavy metals in the street dust are mainly derived from mixed sources of natural, industrial and traffic-related source (54.64%). Both the geo-accumulation index and potential pollution index shows the pollution levels of different heavy metals in different functional areas: from unpolluted, moderately polluted to heavily polluted. A health risk assessment shows no non-carcinogenic and carcinogenic risk of heavy metals to children and adults. Among the five functional areas, the industrial area has the highest non-carcinogenic and carcinogenic risk compared to that of the others.