EVALUATION OF THE ENVIRONMENTAL IMPACTS OF MINING OF PRECIOUS METALS IN ANKA AND GUSAU NORTH- WESTERN, NIGERIA

Abstract

This study was carried out to assess the Environmental and Health implication of precious metal mining and processing in the immediate environment of Brithway minerals and the illegal mine site in Sunke, Zamfara state. Representative samples of soil and water were taken using global positioning system from 21 locations within the study areas. Physio-chemical parameters and concentration of heavy metals Pb, Zn, Ni, Cd, As ,Mn, Hg were analysed using atomic adsorption spectrometer and X-ray fluorescence. pH, Total Dissolve Solid, conductivity and Dissolve Oxygen test were carried out using meter electrodes while moisture content obtained by dry oven method. The soil samples were prepared and digested using standard ASTM procedure. All results were compared with background values as well as the WHO standards for drinking water and the tolerable limit for soil by the European director general environment (ECDGE). Test results shows some physio-chemical parameters exceeding background values and below threshold limit values, the potential for TDS increase and dissolve oxygen decrease due to mining and processing activities cannot be rule out. Metal results show lead (Pb) values in all water samples above 0. 01mg/l attributable to in-situ presence and gets as high as 104.09mg/l in abandon ponds which are as result of athropogenetic activities. Mercury (Hg) values of 0.16mg/l were found in tailing samples and wash water with values of 0.046mg/l. This is of concern considering the harzardous nature of mercury and its bio-accumulative tendency. Field investigation reveals negligence, ignorance and the absolute neglect of good mining and processing practice; lack of personal protective equipments, improper waste disposal, engaging teenagers among other wrong practice, the consequence is the increase in values of heavy metals above background samples and above threshold limit in some cases with the possible attendant effect on health.