Abstract

Problems of water borne diseases are expected where water quality to a community has been compromised. This was the case of Ayede Ekiti, southwestern Nigeria where cholera epidemic was reported recently. Hydrochemical investigation of twenty-seven groundwater and 3 surface water samples from the town were thus, carried out. This was aimed at evaluating major ions and their origin; establish hydro-chemical facies and determine their suitability for drinking and irrigation purposes. Electrical conductivity and pH were measured in-situ, while other hydrochemical analyses were carried out in the laboratory. The suitability of the waters for irrigation purposes was evaluated using Wilcox’s diagram, Kelly’s and Magnesium ratios. The source of ion in water was examined and classified using the Gibb’s diagram. From the geochemical results, it was found that sodium and chloride are the most predominant ions of the total chemical budget. The pH ranges from 7.5 to 7.9, electrical conductivity range from 30 to 900 µs/cm. The hydrochemical characteristics of the water revealed that, the cationic concentrations is in the order of (Na+k)>Ca²⁺>Mg²⁺ for both wells and surface waters, while the anionic concentrations is in the order of Cl^->HCO^-₃>SO₄^-2. The hydrochemical facies of both surface and groundwater were found to be three: CaNaCl>CaHCO₃>NaCl. Wilcox’s, Kelly’s ratio and magnesium ratios suggested that, majority of water samples are good for irrigation. Also, the source of the ions in the waters was examined and classified accordingly as rock weathering dominance. The results show that, the water resources are suitable for drinking and irrigation at the time of study. The source of cholera outbreak was concluded to be from anthropogenic sources. Further studies will be made in the next stage of research.

Key words: Water quality, Wilcox, groundwater, piper diagram, irrigation.