The impact of small-scale mining activities on the levels of mercury in the environment: The case of Prestea and its environs

Abstract

To obtain the baseline information of mercury pollution due to gold mining activities in Prestea and its environs total mercury (T-Hg) concentrations were measured in water and stream sediment. The samples were analyzed by instrumental neutron activation analysis (INAA). They were irradiated and counted without any preconcentration. Higher levels of T-Hg concentration were found in samples at the sites with extensive small-scale “galamsey” gold mining activities than at the sites with low small-scale “galamsey” activities. Concentrations varied between 6.80– 19.82 mg/l for water and 28.90–84.30 mg/kg in sediment at sites with extensive small-scale mining activities. At low small-scale mining sites concentration levels for T-Hg varied between 0.50–9.10 mg/l and 1.20–22.75 mg/kg in water and sediment, respectively. The concentration levels of T-Hg in water from all the sampling sites are in excess of the WHO tolerable limit of 0.001 mg/l for drinking water.