Content, speciation and pollution assessment of Cu, Pb and Zn in soil around the lead–zinc smelting plant of Baoji, NW China
2015
Wang, Lijun | Lu, Xinwei | Li, Loretta Y. | Ren, Chunhui | Luo, Dacheng | Chen, Jinghui
The concentration and speciation of Cu, Pb and Zn in soil samples collected around the lead–zinc smelting plant of Baoji, NW China, were determined using X-ray fluorescence spectrometry and the modified European Community Bureau of Reference sequential extraction procedure. The single pollution index (PI) and the integrated pollution index (IPI) were calculated to evaluate the contamination levels of Cu, Pb and Zn in the soil. The mean concentrations of Cu, Pb and Zn in the topsoil samples are 31.8, 41.3 and 102.6 mg kg⁻¹, respectively, higher than their concentrations in the control sample. The concentrations of Cu, Pb and Zn decreased significantly with depth from 0 to 35 cm, while they were relatively constant for depths between 35 and 100 cm. The concentrations of Cu, Pb and Zn in topsoil north of the lead–zinc smelting plant decreased exponentially with distance from the plant. Cu and Zn in the soil are mainly associated with the residual fraction, while Pb is dominated by the reducible and residual forms. The mobile fractions of Cu, Pb and Zn in topsoil are Pb (60.1 %) > Cu (20.1 %) ≈ Zn (20.6 %). The PI for Cu, Pb and Zn varies from 1.1 to 1.4, 1.0 to 2.5 and 1.1 to 2.0, with means of 1.2, 1.4 and 1.4, respectively, indicating that Cu, Pb and Zn are all moderately polluted in the topsoil around the lead–zinc smelting plant. IPI values range from 1.1 to 2.0 with an average of 1.3, showing that the topsoil samples are moderately contaminated by Cu, Pb and Zn.
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