Multivariate statistical approach to identify metal contamination sources in agricultural soils around Pb–Zn mining area, Isfahan province, Iran

The aims of this study are to evaluate the extent of toxic metal pollution in agricultural soils near the Pb–Zn mining area (Irankuh mining area, Isfahan Province, Iran), and to find out their origins. A total of 32 grab topsoil samples collected from an agricultural field were analyzed for toxic metals including Pb, Zn, Ni, Cu, and Cd using atomic absorption spectrophotometry. The results of the analyses showed that the mean concentrations of Pb, Zn, Ni, Cu, and Cd were 51.80, 60.34, 35.75, 12.05, and 1.38 mg/kg, respectively. Multivariate analysis including correlation coefficient analysis, factor analysis and cluster analysis were used to examine the relationship between the toxic elements and also identify their possible pollution sources. According to the factor and cluster analyses, the 5 toxic metals were classified into three groups. The first group comprised of Cu, Zn, and Pb; while the second and third groups were made up of Ni and Cd, respectively. The average value of Geoaccumulation index ( I geo ) for Ni, Zn, Cu, Pb, and Cd in the soil samples were obtained to be 0.23, 0.80, 0.96, 1.60, and 4.62, respectively. Geoaccumulation index evaluation indicated that the agricultural soil samples were moderately polluted with respect to Zn, Cu, and Ni; moderately to strongly polluted with respect to Pb; and heavily to extremely polluted with respect to Cd. Results of this study can be used for planning and performing appropriate future remediation activities at the site.