Assessment of Heavy Metals Contamination in the Soil of Ay Ghalasi Abandoned Lead-Zinc Mine Area, Southeast Takab

Soil, as one of the important elements of lithosphere and a part of ecosystem plays a crucial role in the life cycle. The goal of the presentresearch was to assess the influence of mineralization and abandoned Ay-ghalasi lead-zinc mine on the distribution of heavy metals andpollution in soil throughout the region. In this regard, 4 soil samples from tailing aroundthe mine and 23 residual soil samples from whole basin, 5 to 20 cm depth, considering the stratigraphy of the region and the distance to the mine were taken. The ICP-OES techniques were employed to determine the concentration of heavy metals (Pb, Zn, As, Cd, Cu, and Ag) in tailing and residual soil samples. The results show that the mean concentration of the heavy metals namely Pb, Zn, As, Cd, Cu, and Ag are 9187.2, 9392.3, 630.8, 0.2, 1005.9 and 61.1 respectively (all in mg/kg), which all are higher than the mean of world soil (MWs) except for the Cd, and also higher than the Dutch standard except for the Ag. In the vicinity of the mine, the concentrations of the metals are high, decreasing with the distance from the mine and the mineral vein. The concentration of Pb, Zn, As, and Ag in the control samples were higher than the MWs and the Dutch standard that is an indication of high background concentration of these elements in the region. In terms of Geo-accumulation Index, Enrichment Factor, Contamination Factor, Contamination Degree, and Pollution Load Index, the soil of the mine area shows high to infinite level of contamination. The elements Pb, Zn, Cu, and Ag have a high Pearson correlation factor.