Heavy metals concentrations and usability of groundwater at Mahd Adh Dhahab gold mine, Saudi Arabia

摘要

The purpose of this study is to evaluate the environmental and social impact and operational water quality in the Mahd Adh Dhahab gold mine area and its surroundings in the central part of the Arabian Shield, Saudi Arabia. This study investigates the distribution of heavy metals in the groundwater from the Mahd Adh Dhahab gold mine area and its surroundings to examine the contamination level of heavy metals in this water due to mining activities. Analytical results of 23 samples from different drains and Wadis of the study areas indicated that water has relatively high concentrations of Na (average 1,916 ppm), Al (average 1. 2 ppm), Fe (average 1. 2 ppm), and B (average 2. 9 ppm). Other elements exist in very low concentrations (less than 0. 5 ppm). The heavy metals distribution shows no specific patterns in the studied wells. Although the concentrations of some heavy elements such as Cu, Zn, and Pb are high due to their abundance in the exposed mineralized veins in the Mahd Adh Dhahab gold mine, no abnormally high concentrations of these elements were found in the studied water samples. This suggests no obvious pollution effects of the mining activities on the groundwater. Except Fe and Mn contents, the groundwater in the Mahd Adh Dhahab mine area and its surroundings have lower metals concentrations compared to the World Health Organization guidelines for drinking water quality and water quality criteria for livestock set by the Ontario Ministry of Environment, which can indicate the validity of such water as drinking water after treatment for Fe and Mn. The concentrations of heavy metals in the studied water samples also have very low values compared to the Desirable Contaminant Concentration and Acceptable Contaminant Concentration values suggesting no pollution effect of the mining processes on the water quality. This in turn indicates the validity of the water in the mine area as well as the surrounding areas for agricultural uses.