Heavy Metal Contaminations at Two Iranian Copper Mining Areas and the Remediation by Indigenous Plants

Background: High concentrations of various heavy metals of mine tailings can easily contaminate the environment. Such materials need monitoring and remediation to prevent them from polluting the environment and food chain. Methods: The concentrations of certain metals were evaluated in the soil samples at Sorkheh and Mazraeh copper mining areas in northwestern Iran, using three reliable pollution indices. We assessed the ability of three plants, Alhaji maurorum and Stachys inflata at Sorkheh mines, and Cirsium vulgare at Mazraeh mines, the dominant plants grown in those areas, in taking up the metals from the associated soils. The plant and soil samples were analyzed inductively by coupled plasma-mass spectrometry (ICP-MS). Results: The results revealed that the soil samples at Sorkheh and Mazraeh mining areas were highly contaminated with As at CF values of 16.9 and 4.6, respectively. The soil samples from the two mining areas were moderately contaminated with Pb and Zn. The data confirmed that A. maurorum and S. inflata had a good ability to accumulate Cd, Mo and Sc from the soils in Sorkheh area. The other plant, C. vulgare, accumulated Zn and Pb at 1891 mg/kg and 18.6 mg/ kg, respectively. The studied plants were good indicators of heavy metals contaminating the soils in these mining areas. Conclusion: This study provided geochemical evidence about the heavy metals that contaminated the soils in the mining areas, and contributed new information about these toxic metals and their concentrations in the three plants and the soil samples.