Assessment and quality monitoring of surface-groundwater water in Chahar Gonbad copper mining area, affected by tailings dam

In order to influence the possible leakage of Chahar Gonbad copper tailings dam on water resources in the dam area, surface and groundwater quality studies were performed in two seasons, dry and wet. Some 10 water samples from different parts of the tailings dam area were evaluated for water quality analysis including Wilcox and Schuler. The results showed that the drinking and agricultural water samples in the region is in line with global environmental standards. The amount of chloride in the drainage water of the tailings dam was 499 mg / l, which is 99 units higher than the defined standard of Iranian drinking (400 mg / l) and 149 units higher than the standard agricultural level (350 mg / l). Also, the results showed that the amount of magnesium in the dry season compared to the wet season has a relative increase. That high amounts of magnesium compared to calcium in water in the irrigation system have a negative effect on soil quality and lead the soil to alkalinity. Molybdenum in tailings dam samples in both wet and dry seasons is higher than the standard level of agricultural use (10 mg / l), which is more evident in the dry season. The high concentration of molybdenum in waste samples is due to the proper mobility of this element in oxidative-acidic conditions. The amount of bicarbonate in the dry season increased more significantly than in the wet season. This increase can be due to the increasing temperature, pH and increase in water alkalinity, the source of those river bed rocks that with increasing water volume in the dry season has increased the concentration of these salts. Based on the results, it is suggested that 23 observation wells with a maximum depth of 50 meters be dug as monitoring grade 1 around the tailings dam of Chahar Gonbad copper mine.