Distribution patterns of lead in urban soil and dust in Shenyang city, Northeast China.

We investigated the spatial distribution of Pb in soil and dust samples collected from 54 sites in Shenyang city, Liaoning province, Northeast China. Soil background Pb concentration was 22 mg kg(-1) and control values from non-industrial areas were 33 mg kg(-1) for soil and 38 mg kg(-1) for dust. Soil Pb concentrations varied widely, ranging from 26 to 2911 mg kg(-1), with a mean concentration of 200 mg kg(-1), 9 times the background value and 6 times the control value. There was great variation in soil Pb, with a coefficient of variation (CV) of 1.06 and a standard deviation (SD) of 212 mg kg(-1). Dust Pb concentrations fluctuated from 20 to 2810 mg kg(-1), with a mean value of 220 mg kg(-1), almost 6 times the control value. No significant differences in distribution were observed between soil Pb and dust Pb. The highest Pb concentration was observed in Tiexi district in an industrial area. Soil Pb concentration decreased with depth and with distance from the pollution source. Lead concentrations initially changed little but then decreased with distance from the roadside, and were generally higher on the east side of roads than on the west. Lead contents in different categories of urban area differed substantially with dust and soil Pb concentrations decreasing in the sequence: industrial >business >mixed (residential, culture and education)> reference areas.