Abstract:
The concentrations and distribution characteristics of heavy metals in Beijing city soils in 2005-2014 were collected and analyzed systematically, in order to explore the variations of soil quality generated by urban expansion and the space-time changes of soil environment under the urban development. The results indicated that the mean concentrations of Cu, Pb, Zn and Cr in soils in Beijing were 31.39, 31.76, 87.88 and 57.90 mg/kg, respectively, which were significantly higher than the corresponding background values (P=0.00). There was no significant difference between mean concentration and background value for Cd in soils in Beijing (P=0.464). The concentrations of heavy metals in loop lines of Beijing showed a decreasing trend from inside to outside. Accumulations of Cu, Zn, and Pb were found in 2nd Ring Road, while Cu, Zn, and Cr in 3rd, 4th, and 5th Ring Roads. As for functional zones, the highest synthetical pollution index was 2.27 in soils from parks, followed by residential area (1.96), traffic area (1.90) and institutes area (1.87). High concentrations of Cu and Pb were found in soils from Park, with higher Zn and Pb in resident area, and Zn and Cu in traffic area and institutes area. Therefore, accumulations of Cu, Zn, Pb and Cr in soils were urgent concerns in management of soil quality, and more attentions should be paid to the accumulations of heavy metals in soils from parks in Beijing.
