Impact of mining on groundwater quality in SW Ashanti, Ghana: a preliminary study

The focus of this research work is on the determination of the impact of mining on the groundwater quality in the historical mining region of SW Ashanti region in Ghana. This work describes the characteristics of the groundwater chemistry and pollution of the aquifer in the gold-ore bearing formation, which is highly weathered and fractured. The fractures control the permeability and depth of the groundwater within the studied area. The concentrations of the major ions and trace elements (As, Fe, Cu, Mn and Zn) present are determined in 63 groundwater wells at dry and wet seasons. The results obtained showed that the concentrations of some ions and elements were below the World Health Organization (WHO) guideline values for drinking water. However, concentrations of the As and Fe ions were very high above the guideline values. The wells with high As and Fe concentration levels might be located at an apparent rock fractured zone that extends to a nearby mine. Such fractured zones allow groundwater to move more rapidly away from a mine, creating more severe mine-drainage pollution in their paths. The results obtained from this study suggested a possible risk to the population of the studied area, given the toxicities of the As and Fe ions, and the fact that for many people living in the studied area, groundwater is a main source of their water supply.

Keywords:

Gold deposits , Mining , Groundwater , trace elements , SW Ashanti