Parent Material Impact on the Geochemical Characteristics of Heavy Metals in Some Important Geological Formations in Zanjan Province

Concentrations of heavy metals in soil depending on the parent material and the pedogenic and geochemical processes affect the distribution. This study aimed to determine the concentration and distribution of some heavy metals in soil geochemical distribution derived from different parent materials in the major geological formations in Zanjan province. For this purpose, number of 67 samples of surface soils from different parent materials, which includes 19 samples igneous parent materials (soils with parent material andesite, basalt, granite, volcanic tuff), 17 soil with sediment parent materials (soil parent material with shale and sandstone) and 31 samples from alluvial deposits were taken. According to the results, the highest mean Cu (38.6), Zn (191.7) and Pb (85.5) in the alluvial parent material, Cr (31.5) and Ni (66) in soils with shale parent material, manganese in soils with granite parent material (674.4) and andesite (673.8) and iron in the soil parent material andesite with (19800) and shale (18600) mg/kg were recorded. The total concentration of cobalt and cadmium in the soil parent material did not show substantial changes. Soil chemical fractionation of various metals was varied. Mobility factor for elements were obtained: Pb(29.8)>Co(25.1)>Ni(18.5)>Cu(6.2)>Zn(5.1). The highest levels of enrichment factor for elements Pb, Zn, Cd and Cu in alluvial parent materials, enrichment factor of nickel, cobalt and manganese in the soil parent material andesite and that for chromium and nickel in soil enriched with shale parent material was obtained. Geo-accumulation indicators showed the similar results.