Contamination of Surface Water around Coal Mining Sites in Ankpa Local Government Area, Kogi State, Nigeria

Abstract

Aims: This study was conducted to evaluate the impact of coal mining activities on surface water quality around coal mining sites in Ankpa Local Government Area (LGA), Kogi State, Nigeria in June, 2024. Methodology: A total of 36 water samples (12 samples each from upstream, midstream and downstream) were collected using 1-liter plastic container, preserved in ice-chest and transported to the laboratory for analysis. Heavy metals (Aluminum – Al, Iron - Fe, Chromium - Cr, and Zinc - Zn) and microbial analysis were performed using standard laboratory procedures. Data collected was analyzed for descriptive statistics using GENSTAT Discovery Software. Results: Among the heavy metals analyzed, Al concentrations were within the lowest range (0.83 to 0.86 mg/L) but higher than secondary maximum contaminant level (SMCL). Conversely, the concentration of Fe across all sites were highest (6.55 to 6.61 mg/L). The chromium levels were within 1.85 to 1.95 mg/L which is higher than the WHO provisional guideline value of total chromium.  Zinc levels across the sites were relatively stable (3.93 to 3.96 mg/L). Higher deposition of coliform were at the downstream while bacteria growth was only observed in the midstream. Salmonella spp, Shigella spp, and Enterobacter spp were recorded in all the sampling sites. At the upstream, the coliform count was 6.0 x 10⁵ CFU/ml, which was the lowest. At midstream, the coliform count was 4.0 x 10⁶ CFU/ml while downstream had values of 5.6 x 10⁶ CFU/ml. There was no bacterial growth at the upstream and downstream using nutrient agar and MacConkey agar. Conclusion: The findings underscore the need for regular water quality monitoring, environmental remediation efforts, and enhanced community engagement to mitigate the environmental and public health risks posed by coal mining activities in coal mining sites in Ankpa LGA, Kogi State, Nigeria.