Acid Mine Drainage: Effect of acid mine drainage on water and soil resources within the Bogoso/Prestea Mine Resource. (Bogoso Concessional Area)
Heavy metals contamination (As, Fe, Cu, Zn, Mn and Cd) and other physico-chemical changes (pH, temperature, EC, DO, alkalinity, S042-, free CN) in underground and surface water, and carbonate carbon and sulphate sulfur in soil samples due to the effect of acid mine drainage (AMD) were assessed around Golden Star Resource Mine (Bogoso concession). Underground and surface water samples were collected from seven different sites and soil samples from three different sites within Golden Star Resources Mine (Bogoso concession) between November, 2006 and April, 2007. Atomic Absorption Spectrometry (AAS) was used to determine the heavy metal concentrations whilst the physico-chemical parameters were determined using standard methods. Average total levels of arsenic, iron, copper, zinc, manganese and cadmium were 0.0313, 3.7675, 0.0518, 0.0382, 0.8102 and 0.008 (mg/l) and average dissolved levels were 0.0104, 0.6737, 0.0356, 0.0256, 0.6998 and < 0.005 (mg/l) in surface water respectively. In underground water, average total levels of arsenic, iron, copper, zinc, manganese and cadmium were 0.0058, 5.8220, 0.1676, 0.0339, 0.2521 and 0.0065 (mg/l) whilst average dissolved levels were 0.0050, 4.3496, 0.1219, 0.0215, 0.2239 and 0.006 (mg/l) respectively. Iron and manganese levels in surface and underground waters exceeded Ghana Environmental Protection Agency standards for mining effluent. Differences in pH, temperature, E.C, alkalinity, S042-, iron, Cu, Zn and Mn levels in the seven water samples were statistically significant (p ≤ 0.05). Surface water samples recorded values of EC and S042- ions higher than in underground water samples which exceeded acceptable limits. Carbon and sulfur in soil samples varied from 0.1922 to 1.8247 % and 0.0237 to 1.5830 % respectively. The results of the study showed high impact of AMD on water quality in Bogoso mining area. This effect could be attributed to the release of metals as a result of oxidation of metal-bearing sulphides in the mine dumps and pits at the selected sampling sites. The study showed that addition of lime as a treatment option has not been effective. Hence new conventional methods should be considered in the treatment of acidic water (AMD) in the mining area.
A thesis submitted to the Department of Applied & Theoritical Biology, Faculty of Bioscience, College of Science, Kwame Nkrumah University of Science & Technology, Kumasi in partial fulfilment of the requirements for the degree of Master of Science. (Environmental science)