Heavy metal pollution status in soil for different land activities by contamination indices and ecological risk assessment

The purpose of this study was to assess the heavy metal pollution status in urban soil under different land uses, by using contamination and ecological risk assessment indices in Kerman,Iran. Soil samples were extracted by acid digestion, and concentrations of Al, Cd, Cu, Cr, Hg, Ni, Pb and Zn were measured. For pollution analysis, the PI, NIPI, Igeo, EF, PLI, Cd, mCd, Eri\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${E}_{r}^{i}$$\end{document} and RI indices were employed. The highest PI value was of 8.38 for Pb in the new terminal area, and 7.0 for Hg in the gas station area. According to the NIPI, the new terminal (4.51) and the old terminal (4.22) areas were in the high pollution category. The Igeo value for Pb and Hg fell in class 3, indicating moderate to high pollution and for Zn, and Cd fell in class 2, and indicated moderate pollution. The EF analysis showed all samples from the gas station area to be enriched in heavy metals. The PLI analysis showed almost all samples from urban land use areas to be polluted with heavy metals. The Cd and mCd showed that the highest pollution was in the new terminal (Cd = 26.8, mCd = 3.35) which sat in class 4 and 3, respectively. The Eri\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${E}_{r }^{i}$$\end{document} indicated that the levels of Hg were considerable and imposed a high ecological risk, but Cd values were low and imposed moderate potential ecological risk. The RI of soil in the present study area was 1632.7, 536.02 and 180.64, for Hg, Cd and Pb, respectively.