An Investigation on Groundwater Chemistry from Geologic Controls on Water Sources around Ikare – Akoko Area, Southwestern Nigeria

Abstract

The study area, Ikare and its environ is located in Akoko North East Area of Ondo State, Southwestern Nigeria. It lies between longitude 5⁰45^IE and 5⁰52^IE and latitude 7⁰31^IN and 7⁰35^IN. It covers an estimate area of about 30km² with prominent settlements like Ikare, Ugbe, Iboropa and Arigidi. The study area is very accessible (roads and footpaths) making close observation of hand-dug wells, boreholes and surface waters easier. The geology of Ikare-Akoko area from field work shows that it lies within the Migmatite-Gneiss-Quartzite complex of the basement complex of south-western Nigeria.

A total of thirty (30) water samples obtained from hand-dug wells, boreholes and surface waters within the three rock types were analysed for their physico-chemical properties. This is aimed at assessing their quality and usability as some physical and chemical parameters show average values. Statistical analysis using the Principal Component Analysis indicates that Ca, Cl, Conductivity and Fe are the major components that determine the groundwater chemistry in the study areas. Two water types dominant in the study areas include sodiumand calcium bicarbonates.They reflect effects of bedrock lithologies and base exchange processes from geologic controls on the chemistry of water sources in the areas.

Geophysical applications needed in determining the water yield in the area.