Physico-Chemical and Microbial quality of Surface and Ground water Resources in the Obuasi Gold Mining area
In most mining towns in Ghana, access to clean and potable water is a great challenge, resulting in waterborne diseases. The aim of this study was to assess the levels of some physical, chemical and microbial water quality parameters in 18 rivers and streams, 15 boreholes and 3 hand-dug wells at Obuasi, a gold mining town in southern Ghana. Parameters were determined using standard procedures. Statistical comparison was made between the levels of various water quality parameters with respect to the distance of the water source from the mining or hotspots areas. This was done by performing mean comparison test for the water quality parameters under study. The results showed that ground water pH ranged between 4.91–6.31with a mean value of 5.38 ± 0.35 pH unit, which was acidic than surface water (pH range 6.02– 7.45 and mean 6.59 ± 0.32 pH unit). Surface water which recorded a conductivity range of 48.99–1141.9 μS/cm and a mean value of 439.94 ± 410.84 μS/cm in the study area which were, more mineralized than ground waters (with conductivity range of 34.46–742.11 μS/cm and mean value of 186.62 ± 188.00 μS/cm). The quality of surface water samples close to the mines was found to be generally poorer than for samples outside the mines. Significant differences were found between, Conductivity, TDS, Hardness, Sulphate and Arsenic levels for the surface water samples close to the mines compared to the water samples outside the mine. However, parameters such as pH, NO3-, Fe, Pb, Cu and Cd levels showed no significant locational variation. Moreover, Coliform population, NO3-, As, Fe, Pb and Cd levels in most cases, exceeded the World Health Organization recommended thresholds for potable water. In conclusion, the quality of most of the streams, boreholes and hand-dug wells were not suitable for human consumption without adequate treatment.
A Thesis submitted to the Department of Environmental Science of the Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirement for the degree of Master of Science in Environmental Science, June-2012