Geoelectrical, hydrochemical, and health risk assessment of groundwater quality in Fountain University, Osogbo, Nigeria

Geoelectrical method and physiochemical analyses were applied to obtain subsurface resistivity variation and water quality assessment respectively in Fountain University, Osogbo, Osun State. A young academic institution with a measurable growing population is seriously concerned with the hygienic situation within its environment, especially water quantity and quality. The geophysical method was employed to determine the subsurface groundwater potentials via vertical electrical sounding (VES) using the Schlumberger array. Ten (10) water samples were collected from different locations within the study area and analyzed for physiochemical parameters and trace metals using standard procedure. Water quality index (WQI), exceedance, and human health risk index were determined. All parameters estimated were below the WHO permissible limits except the pH and iron concentration. WQI values of the ten collected water samples reflected 100% excellent grade for drinking. Chronic dietary intake (CDI) is in the order of Fe >Zn > Cu for both children and adults. The VES (9 location points were studied) data revealed four to five geo-electric layers which corresponded to the topsoil, lateritic clay, weathered layer, fractured basement, and fresh basement with thickness ranges of 0.5 to 39.6 m, while resistivity values vary from 27.5 to 5432.6 Ωm. The study observed and recommended that boreholes could be sunk at VES 1, 6, and 7 at depths between 26.1 to 39.6 m for exploitation of good quality water along with continuous monitoring of groundwater quality to maintain the good water quality area, hence the safety of the environment.