Share of Natural and Anthropogenic Resources in Heavy Metals Distribution in the Soils arround Venarch Manganese Mine in Qom

The aim of this study was to evaluate contamination of the soils around Venarch manganese mine in Qom with heavy metals such as manganese, nickel and lead. It is also attempted to compare the Muller’s and Karbassi’s methods for determining the pollution index and the natural and anthropogenic share of the mentioned elements in the study area.  in of Geoaccumulation index (Igeo) and (Ipoll), heavy metals of natural and anthropotogenic fase contribution in the region. To perform this study, 3 samples were systematically collected from soil at the depths of 5 - 25 cm and mixed together to make a compound sample which was transferred to the laboratory. The concentrations of manganese, nickel and lead were measured using a spectrophotometer. Then the Muller’s Geoaccumulation index (Igeo) and the Karbassi’s Pollution Index (Ipoll) were employed to determine the intensity of pollution in the study area. The results of bulk digestion showed that concentrations of Mn and Ni are lower and concentration of Pb is higher than the maximum average concentrations in the Earth’s crust and shale. Igeo was in the range of 0-1 and Ipoll was in the range of 1-2 for all metals, respectively showing that soil pollution is classified as unpolluted and slightly polluted.
Karbassi’s Ipoll was found to be more efficient than Muller’s Igeo in determining the amount of contamination in the region. The share of heavy metals in anthropogenic phase was determined as the following order: Pb (16%)> Ni (8%)> Mn (5%).