Levels of mercury, cadmium, and zinc in the topsoil of some selected towns in the Wassa West District of the Western Region of Ghana

Abstract

The Wassa West istrict of the western region of Ghana is noted or a large deposit of gold ores. s a result, there is a lot of mining activity in the district, which include both legal and illegal miners. large number of illegal (“galamsey”) miners employ mercury in the amalgamation of gold, whereas some of the mining companies use inc dust (with associated cadmium impurities) in the extraction of gold. ue to the otentially toxic and adverse effect of mercury and cadmium on humans, livestock, and aquatic organisms, this research seeks to determine the concentration of mercury, cadmium, and inc in the topsoil (up to 30cm), which constitutes the absorption one of most ood crops grown in the district, and compares these levels with literature values as well as control samples taken rom other non-mining districts, thus assess the ollution due to these metals. The results or mercury gave a eak average concentration of 2.8 mg/kg around boso and decreased to 0.41 mg/kg at ompem to the south and 0.33 mg/kg at uni Valley to the north. ll these concentrations were higher than those ound in the control samples as well as the standard (0.3 mg/kg) ound in literature. The contamination of control samples with mercury suggests aerial distribution of the metal. inc concentrations, however, did not show any trend that could be due to anthropogenic sources or natural deposition of the metal. owever, high concentrations of 387 mg/kg at boso, 170 mg/kg at Tarkwa, and 221 mg/kg at ompem give an indication of the use of inc dust in the extraction of gold. The research, however, did not detect cadmium above the detection limit of the instrument used