Effects of Small-Scale Gold Mining on Surface and Ground Water Quality in the Bogoso/Preastea Mining Area

Abstract

Sampling and analysis of water samples from rivers and boreholes in the Bogoso/ Prestea mining area in the Western Region of Ghana were conducted with the aim of assessing the possible effects of mining on water quality. Water samples were collected for 6 consecutive months at ten sampling sites within the study area and levels of some heavy metals (Hg, Fe, Mn and As) and nutrients (sulphates, phosphates, nitrates and chlorides) were determined. The results show mean concen-trations of 0.001-0.017 mg/l, 0.013-13.64 mg/l, 0.003-1.06 mg/l and 0.001-0.02 mg/l, respectively for Hg, Fe, Mn and As in the water samples. Respective mean concentrations measured for sul-phates, phosphates, nitrates and chlorides are 0.1-48 mg/l, 0.8-7.0 mg/l, 0.32-4.73 mg/l and 7.9-135.5 mg/l. The results indicate that most of the measured parameters were present at levels that are above the WHO guidelines for drinking water, depending on the proximity of the sampling site to a mining activity