Levels of arsenic and antimony in water and sediment from Prestea: A gold mining town in Ghana and its environs
Arsenic and antimony concentrations in water and sediment samples collected from Prestea, a gold mining town in the Western Region of Ghana and its environs were studied. The concentrations of these elements were measured using instrumental neutron activation analysis (INAA). INAA was preferred to other modern analytical techniques because of its relatively higher selectivity, sensitivity and high precision. Beside its multi-elemental nature, INAA is very fast and thus presents a very good analytical tool for the determination of elemental concentrations in various samples including water and sediment. The samples were irradiated using a 30 kW tank-in-pool Ghana Research Reactor-1 (GHARR-1) operating at a thermal neutron flux of 5 × 1011 n s−1 cm−2. The samples were irradiated and counted without any chemical treatment. Elevated levels of As and Sb were found in both water and sediment. Generally, As and Sb concentrations in the water samples ranged from 0.90–8.25 ppm and 0.09–0.75 ppm respectively. These values far exceed the WHO recommended values for As and Sb in water, 0.01 ppm and 0.005 ppm respectively. The levels of As in sediment ranged from 942–10,200 ppm, and that of Sb was 8.5–90.4 ppm. Arsenic concentrations in both water and sediment were generally higher than Sb concentrations. This is, however, not surprising as arsenopyrites (FeAsS2) are among the major pathfinder minerals associated with gold mined from Ghana. Our results show that the study area is polluted as far as the levels of As and Sb in water and sediment are concerned.