Cent. Eur. J. Eng. • 2(2) • 2012 • 304-313 DOI: 10.2478/s13531-011-0052-3 The environmental impact of gold mines: pollution by heavy metals Sabah Ahmed Abdul-Wahab 1* , Fouzul Ameer Marikar 2 1 Department of Mechanical & Industrial Engineering, College of Engineering, Sultan Qaboos University, Sultanate of Oman 2 College of Engineering, Sultan Qaboos University, Sultanate of Oman The gold mining plant of Oman was studied to assess the contribution of gold mining on the degree of heavy metals into different environmental media. Samples were collected from the gold mining plant area in tailings, stream waters, soils and crop plants. The collected samples were analyzed for 13 heavy metals including vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), cadmium (Cd), cobalt (Co), lead (Pb), zinc (Zn), aluminium (Al), strontium (Sr), iron (Fe) and barium (Ba). The water in the acid evaporation pond showed a high concentration of Fe as well as residual quantities of Zn, V, and Al, whereas water from the citizens well showed concentrations of Al above those of Omani and WHO standards. The desert plant species growing closed to the gold pit indicated high concentrations of heavy metals (Mn, Al, Ni, Fe, Cr, and V), while the similar plant species used as a control indicated lesser concentrations of all heavy metals. The surface water (blue) indicated very high concentrations of copper and significant concentrations of Mn, Ni, Al, Fe, Zn, lead, Co and Cd. The results revealed that some of the toxic metals absorbed by plants indicated significant metal immobilization. Environment • Gold mining • Heavy metals • Pollution • Tailings • Soil • Water © Versita sp. z o.o. 1. Introduction Mining has been identified as one of the human activities which may impact negatively on the quality of the environ- ment [1]. It causes the destruction of natural ecosystems through removal of soil and vegetation and burial beneath waste disposal sites [2]. In principle, mining waste can be divided into two categories: (i) mine tailings, generated when processing the ore, and (ii) waste rock produced when uncovering the ore body. Many processing methods for minerals involve grinding of rock and ores, recovery * E-mail: sabah1@squ.edu.om of the desired fraction and disposal of the wastes, often as slurry, to a tailings or retention pond. More than 99% of the original material may finally become tailings when low-quality ores are utilized [3]. Impacts of mining range from physical/habitat destruction with accompanying the loss of bio-diversity resources to the accumulation of pollutants in different media of the en- vironment [4]. Therefore, the mining sites are a permanent toxicological problem for the surrounding ecosystems and human health [5]. Like any productive activity, the exploita- tion of mineral resources produces negative impacts upon the three elements in the environment: water, atmosphere and soil [6]. The mining sites are often contaminated with several kinds of heavy metals that come primarily from the processing