Concentration and speciation of heavy elements in soils and plants around Ijo porphyry copper mine (NW Share-Babak, Kerman province)

Heavy metal concentration and speciation in soils and native plants around the Ijo copper mine (Kerman province) are investigated in the present study. For this purpose, 34 soil samples (0-40 cm in depth) and 8 native plants (Artemisia sp.) are collected and analyzed by means of standard methods. In addition, chemical forms of heavy metals are determined by Tessier five-stage extraction procedure. The results obtained indicated that Cu (457.25 mg/kg on average) in potassic alteration zone and As, Pb and Zn in argillic (47.06, 137 and 580 mg/kg on average, respectively) have the highest concentrations. The calculated enrichment factor (EF) and geo accumulation indices (Igeo) also confirmed this distribution pattern. The results of sequential extraction method indicated that all the metal studied have relatively low proportion in the exchangeable fraction (F1, 1/89 % of their total contents) and high contribution in the residual fraction (79/70 % of total contents) implicating their main geogenic sources in the soils. Levels of heavy metal in Artemisia and based upon the calculated biogeochemical indices (Transfer factor-TF and Bioconcentration factor-BCF), it was revealed that Zn and Cr (Mn as well) have the highest and lowest transfer factors, respectively. Also, the highest BCF are calculated for Mo, Cd and Cu. This study generally concludes that although the metals in soils are inherited mainly from the natural or lithogenic source in the study area, intensive exploitation and mining activities might enhance the soil metal contamination rate and make metals more available that it should be considered in future assessments.