Studies of the Levels of Some Toxic Elements in Soil and Tailings from Bibiani Mining Area of Ghana

E. Quarshie ； B.J.B. Nyarko ； Y. Serfor-Armah

《Research Journal of Environmental and Earth Sciences》 3卷5期 (2011/08) Pp. 512-520

並列摘要

The concentrations of the toxic elements As, Cd, Cr, Hg and V in soil and tailings samples from the Bibiani mining area in the Western Region of Ghana have been measured using Instrumental Neutron Activation Analysis (INAA) with the aim of assessing the impact of mining activity on the Bibiani mining environment. All samples and standards were irradiated with thermal neutrons in the Ghana Research Reactor-1 (GHARR-1) facility at the Ghana Atomic Energy Commission, Kwabenya-Ghana, followed by counting with a conventional counting system. The concentrations of the elements measured in the soil were in the ranges: As, 0.46-996mg/kg; Cd, 0.69-4.15mg/kg; Hg, 0.01-0.06mg/kg and V, 60-204mg/kg. In the tailings, the concentrations of the elements were in the following ranges: As, (2.70-3.50)×10^3mg/kg; Cd 1.35-3.36mg/kg; Cr, 19-87mg/kg; Hg, 0.01-0.02mg/kg and V, 48-93mg/kg. The soils were near neutral and reducing (except sample LS, taken from Lineso, a galamsey mining area which had a pH of 4.99) with pH ranging from 4.99 to 7.54 and an average Eh of -64 mV, as were the tailings with pH ranging from 6.63 to 7.62 with an average Eh of -53 mV. Very high levels of As were measured in the tailings and some soil samples very close to the tailings dams of the Central African Goldmine, as well as some areas that used to be galamsey mining areas. This gives the indication that the tailings dams and galamsey mining activities might be the source of As pollution in the area. It was also realized that high levels of the elements As, and V occurred generally in both the soil and tailings samples. The levels of As in the tailings were far higher than in the soil whilst the levels of V in the soil were higher than those in the tailings. The levels of Cr measured in the tailings were quite high but our inability to measure Cr in the soil makes it difficult for us to tell whether these levels have in anyway influenced the levels of Cr in the soil. On the contrary, the levels of Cd and Hg in both soil and tailings samples were relatively low and therefore, did not give any indication of contribution from mining activities, especially large scale mining which was the main focus of this study.

並列關鍵字

Dam ； Eh ； galamsay ； NAA ； pH ； pollution