Concentration and Pollution Assessment of Heavy Metals in Urban Topsoils of Lishui City, China

摘要

This paper reports the concentrations of heavy metals (Cr, Cu, Ni, Pb and Zn) and assessment of pollution level in urban topsoils of Lishui city, Zhejiang Province, China. Pollution index (PI), integrated pollution index (IPI) and geoaccumulation index (Igeo) was calculated to assess the pollution degree of heavy metals in urban topsoil. The mean concentrations of Cr, Cu, Ni, Pb and Zn of the investigated urban soils are 34.66 mg/kg, 35.75 mg/kg, 14.35 mg/kg, 63.10 mg/kg and 191.97 mg/kg, respectively. Compared with the reported data of heavy metal in the world, the concentrations of heavy metals in urban topsoil of Lshui city showed lower metal concentration level. The Cu, Pb and Zn were enriched in the urban topsoils, indicating pollution indexes of 2.01, 2.46 and 2.78, respectively. The PI and Igeo of heavy metals are Pb>Zn>Cu>Cr>Ni. The PI and Igeo of Cr and Ni in urban topsoils are low and do not appear to reach pollution levels, suggesting that Cr and Ni levels were controlled by soil parent materials. These findings indicated that more attention should be paid to heavy metal pollution in the process of urbanization especially Cu, Pb and Zn. The results of this work can be used as the basis for a regular monitoring program for implementing suitable pollution control measures.