Geochemical Evaluation of Groundwater using Electrical Resistance and Physiochemical Methods: A Case Study of Iba Residential Area, Lagos, Nigeria

Abstract

Article history: Received 28 December 2018 Accepted 26 January 2019 Available online 11 February 2019 Geophysical and physiochemical methods were applied to determine potability of groundwater at Iba area, Ojo, Lagos State, Nigeria. The geophysical methods employed for the survey were Vertical Electrical Sounding and Horizontal Profiling, with the aim of determining the depth of potable groundwater. Ten vertical electrical soundings were conducted using the Schlumberger configuration and three horizontal spread covering the entire area. The VES data were interpreted using (WIN RESIST) which showed that the area is composed of top soil, clay, clayey sand, sandy clay and sand. The horizontal profiling data was subjected to iteration software (DIPPRO) which gave the imaging of the lateral variation in resistivity within the study area. The physiochemical analyses of groundwater samples collected in the study area also conducted following standard procedure. The results of the physicochemical analysis compared with acceptable standards of World Health Organization, showed that the water quality within the study area is wholesome. The geophysical results indicated that real aquifer exist at depth from 20 m. The unconfined aquifer is prone to pollution mostly close to the surface. Potable water is therefore recommended to be sunk via borehole at depth from 30.2 m, with the best at VES 4, 8 and 9.