Hydrology survey and water quality assessment of water sources in three selected towns in Osun State, Southwest Nigeria

Recently, the deterioration in water quality of natural water bodies arising from pollution has become a severe global challenge, mainly as a consequence of anthropogenic activities ensuing from farming, population and economic growth, and urban development. This study reports the hydrology survey and water quality assessment conducted within Okuku, Ikire, and Ifetedo townships in Osun State, Nigeria. Field sampling, hydrogeological, in situ data analyses, microbiological and physicochemical assessment of surface and groundwater samples, was carried out between August and September 2020. Microbiological quality and physicochemical characteristics of all water samples were assessed using internationally acceptable methods, and results were compared with globally accepted guidelines for drinking water quality. The surface water reservoirs have the flow characteristics of typical seasonal streams. The water yield from the streams at the time of sampling was exceptionally low in Ifetedo and non-existent in Ikire, but significantly high in Okuku. A total of 33 water samples were evaluated and had most of their parameters within the stipulated World Health Organization guidelines except for lower pH in some surface and well water samples, and higher conductivity values in seven boreholes, one surface and well water sample each, with the highest value at 1100.00 µS/cm. However, the poor microbiological quality of all water samples shows that they are unfit for drinking as well as for various other domestic and agricultural purposes without adequate treatment. These results highlight the relevance of constant monitoring of water quality and the need for proper water treatment policies by the relevant government bodies. © Islamic Azad University (IAU) 2022.