ABSTRACT
The Ikpoba Reservoir, the primary water source for Benin City, Nigeria, Ikpoba Reservoir, a critical water source for Benin City, Nigeria, with a daily production capacity of 34,080 cubic meters (m³) undergoes a comprehensive water quality analysis. On the positive side, several key parameters fell within the acceptable limits set by the Federal Ministry of Environment. These include pH (ranging from 6.13 to 6.68), electrical conductivity (varying between 269.5 and 34.75 µS/cm), alkalinity (5.00 to 41.25 mg/l), sulphate (8.05 to 11.31 mg/l), concentrations of major ions like sodium (3.13 to 10.36 mg/l), potassium (1.58 to 5.42 mg/l), magnesium (1.00 to 2.65 mg/l), and chloride (5.85 to 25.69 mg/l). Additionally, temperature readings stayed within the range of 32.4 to 33.1 °C. Furthermore, some heavy metals, like zinc (0.05 mg/l) and nickel (0.03 to 0.05 mg/l), showed levels compliant with national standards. These findings suggest generally moderate water quality for these parameters. However, the analysis also revealed some concerning aspects. Significant variations were observed across different stations within the reservoir. Levels of dissolved oxygen (ranging from 5.93 to 6.83 mg/l), indicators of organic pollution like biochemical oxygen demand (BOD, 2.68 to 4.00 mg/l) and chemical oxygen demand (COD, 11.3 to 24.25 mg/l), nitrate (varying between 0.68 and 5.42 mg/l), and calcium (ranging from 1.38 to 26.13 mg/l) all exhibited these spatial differences. Notably, station 1 consistently displayed higher values, suggesting potential localized sources of organic matter, nitrate pollution, and specific minerals. Furthermore, the analysis identified a troubling issue – levels of cadmium (Cd, 0.05 to 0.50 mg/l) and lead (Pb, 0.054 to 0.05 mg/l) exceeded the recommended limits for surface water. These observed variations and exceedances necessitate further investigation to pinpoint specific pollution sources, such as agricultural runoff or point source discharges. Analyzing historical data and implementing ongoing monitoring programs are crucial steps to understand the evolving water quality of Ikpoba Reservoir. By taking these actions, we can ensure the long-term health of this vital water source for Benin City.
