Assessment of heavy metals pollution in groundwater of Golgohar iron ore mine area, Iran

摘要

The Golgohar iron ore mine in southern Iran is a large open pit that operates below the groundwater table. Dewatering operations and mining activities could be responsible for generating metal contamination in the groundwater of the area. In order to assess this, groundwater, soil, solid waste and rock samples were collected and analyzed for heavy metals. Evaluation was done by comparing the results with the "heavy metal pollution index'', the "heavy metal evaluation index'' and the "degree of contamination'' (C-d). The only mean concentrations of elements in water samples above the WHO maximum admissible concentration values for drinking water are Al (97 % of water samples), As (46 %) and Mn (34 %). Despite exceeding the concentration of these elements above the permissible levels, the indices show that most of the water samples are low and moderately contaminated and overall contamination levels are not dangerous. The low concentration of the heavy metals in the groundwater of the area is mainly due to the limited presence of sulfide minerals in the ore, combined with the presence of calcite (CaCO3) in the area, which neutralizes any acid generated from sulfide oxidation.