فهرست مطالب اعظم سادات خدایی

The bioavailability of potentially harmful elements such as heavy metals has been ignored in many researches, and most studies are conducted based on total concentration. Considering that the total concentration of metals, in most cases, shows limited information about the mobility and bioavailability of heavy metals, therefore, partial concentration or extraction is the best method in estimating the content of metals in soil. In this study, 40 samples were collected from surface soils around the mine, tailing and agricultural soils around the Ahangaran mine. Total concentrations of lead and zinc were determined by ICP-OES, and the bioavailable fraction was carried out by single-stage method extraction (0.1N HCl) using atomic absorption spectroscopy (AAS). The contamination factor (CF) results for Pb in tailing and around the mine areas indicate very high contamination and moderate contamination for agricultural soils. The amount of CF for Zn presents a very high contamination factor in tailings and moderate contamination factor in the other areas. Pollution load index (PLI) values show that the tailings and soils around the mine are extremely polluted, and agricultural soils are moderately polluted. The Risk Assessment Code (RAC), which was calculated based on zinc and lead bioavailability, presented moderate risk for zinc in all study areas and low risk and for Pb (except agricultural soils that show moderate risk). Low bioavailable values indicate the presence of Pb and Zn in the residual phase (in the form of minerals) that do not pose much risk to living organisms. Increasing the amount of bioavailability in agricultural soils located at farther distances from the mine indicates the presence of these metals in carbonate and exchangeable phases