Borehole Logs and Physico-chemical Investigation of Some Presumptive Springs in Akoko, South-western Nigeria
A geophysical investigation involving the use of Schlumberger configuration and physico-chemical parameters of water samples has been conducted in twenty (20) selected areas of Akoko in Ondo state, south-western Nigeria, with a view of mapping presumptive springs with respect to depth, thickness, resistivity and sediment that have appreciable yield. The data obtained were interpreted by the computer iteration process and have A, HA, H and Q typical curve types as well as topsoil, weathered/fractured layer, and fresh basement. The focus of the borehole log section is a weathered/fractured layer of appreciable thickness in all locations for springs formation and seasonal yield. Physico-chemical parameters of the water samples have been collected with pH ranging from 6.57 to 7.20, EC varying between 1.2× 102 to 4.2 × 102 (uhr/cm), TDS ranging from 0.0 1to 0.55, turbidity from 0.01 to 0.1, DO from 7.8 to 9.6 (mg/l), BOD from 2.8 to 4.8 (mg/l) and COD from 1.6 to 6.4 (mg/l), with the temperature of 25°C to 26°C, which may be from slightly acidic to slightly alkaline. Most of the analyzed samples meet the fixed threshold limit by WHO for drinking purpose of below 10 mg/l values, except the COD and the temperature which are higher than the WHO recommended value by 0.4 and 0.6, respectively, in the first phase of location 3, 5, and 6. People in these locations are likely to have cancer, hence; water purification is recommended before it could be considered safe for drinking.