Ground water quality in Ejigbo town and environs, southwestern Nigeria
This study assessed the physico-chemical parameters and quality of ground water in Ejigbo and environs,
southwestern Nigeria with a view to determining its suitability for human consumption. The concentrations of cations which included Ca2+ , Na+, Mg2+ , K2++ , Zn2+ , Cd2+ , Pb2+ , Fe2+ and Mn2+ ; those of anions such as SO42- , NO3- and PO42- ; the pH and the total dissolved solids (TDS) in twenty-six (26) ground water samples from fourteen boreholes and twelve hand-dug wells (HDW) were determined. The results showed that Na2+ and K +were the most abundant dissolved cations in the groundwater. The concentrations of K+ exceeded the WHO recommended level of (10 12) mg/L in all the samples. The concentrations of Cd exceeded the WHO standard of 0.003 mg/L in 19 wells while that of Pb exceeded the WHO standard of 0.01 mg/L in 9 wells. These are probably attributable to anthropogenic activities. Concentrations of the other ions and parameters like pH and TDS are within the recommended WHO maximum allowable limits for drinking water. The exceptionally high values of cadmium and lead in waters from some wells in the study area showed that the ground water in most of the boreholes and hand-dug wells sampled is not suitable for human consumption. This gives course for concern, since the majority of people living in this area depend on water supply from the handdug wells and boreholes for various domestic purposes. There is, therefore the need to alert the local authority in the area of this dangerous trend, so that an alternative arrangement can be made to provide domestic water for residents of the area.
Key words: Ground water, Physico-chemical Parameters, Cations, Anions and Ejigbo.