Impacts of Limestone Mining and Processing on Water Quality in Ashaka area, Northeastern Nigeria

Abstract

The impacts of limestone mining and processing on water resources in Ashaka area of North-Eastern Nigeria was investigated in this study. Ashaka is located about 140 km north of Gombe town, in between hills and Gongila valley, covering an area of about 25km2. Samples were collected from hand-dug wells, boreholes, surface water, mine ponds and waste water and taken to the laboratory for relevant analysis. The hydrochemical facies analysis revealed three water types in the area in the order of: Ca-Mg-SO4, Ca-Mg-HCO3 and Ca-Mg-SO4-HCO3 an indication that the water type in the area is closely related to the local geology of the area. The high concentration of carbonates and bicarbonates in the water are derived from bedrock dissolution and weathering while fluoride and heavy metal enrichment in the water may be due to mining and processing of limestone in the area and application of fluoride-rich fertilizer. The degree of accumulation of the metals are in the order of Mn > F > Cd > Fe > Cu > As > Pb > Ni > Cr. This implies that Mn has the highest water pollution index while Cr has the least water pollution index. Government all levels should enforce the treatment of industrial effluent before discharging them into the rivers Alternative source of drinking water should be provided to the host communities where their surface and hand-dug wells have been polluted by effluent from the cement factory. Periodic assessment of the various water sources should be undertaken in the area in order to adequately monitor the pollution status of the water resources in the area.