Assessment of Groundwater System Characteristics in Ilorin Metropolis, South-Western Nigeria

Abstract

Geochemical analysis of shallow groundwater from Ilorin metropolis was carried out with the aim of assessing the hydrogeochemical characteristics of the groundwater. Thirty (30) boreholes were examined and samples were collected from these boreholes. These samples were subjected to chemical analyses to determine both cations and anions compositions of the groundwater. The concentrations of cations (trace elements) were determined using AAS at the Department of Geology while major cations were determined using flame photometry emission at the Centre for Multidisciplinary Research Laboratory University of Ibadan. The compositions of anions in the samples were analyzed using titration method at the National Geo-Hazard Research Laboratory, Ibadan. Some physical parameters such as TDS, pH, EC as well as colour and odour were determined insitu. The results of the physical parameters show that EC ranged from 44.3 - 1079μs/cm; TDS 10.6 – 501.0mg/l. The results of the chemical analysis in mg/l for trace elements showed that Cd (0.57 – 0.58), Co (3.84 – 3.87), Cr (3.41 – 3.79) and Ni (0.00 – 0.11); Major elements: Ca (1.20 – 6.60); Mg (2.40 – 5.53); K (1.45 - 5.86) while the results of the anions showed that concentrations (mg/l) of Cl ranged from (6.00 – 229.95), HCO3 (0.20 – 2.18), SO4 (0.01 – 1.47) and NO3 (0.09 – 0.35). Further evaluation of the results shows that samples from areas that are densely populated and dominated with lot of commercial activities have high concentrations of chloride, nitrate, Cd and bicarbonate. The results of the analysis were compared with the WHO Standards and it was observed that Cd and chloride were far greater than WHO Standards recommended for safe drinking wate