Global Journal of Earth and Environmental Science

Presentation of chemical analysis in graphical forms makes understanding of complex groundwater system simpler and quicker. This study examined the signatures of graphical plots to unravel the effects of urbanization on the groundwater quality of Ado-Ekiti and Ijero-Ekiti, southwestern Nigeria. In this study, existing data from Sanitary Surveys and Hydrochemistry of Groundwater in Two Urban Towns (Ado-Ekiti and Ijero-Ekiti), Southwestern Nigeria were employed for the graphical plots. In that study, sixty wells’ water samples (30 each from Ado-Ekiti and Ijero-Ekiti respectively) were involved in the chemical analyses. Sampling operation was carried out by collecting water samples in duplicates at each location into a pre-cleansed polyethylene bottles for anions and cations determinations. The samples for cations analysis were acidified by addition of two drops of concentrated Nitric acid to prevent reactions that may come up before analysis. All samples were kept in a refrigerator at a temperature of 4°C before they were analyzed at the Federal University of Technology, Akure Nigeria. Anions were determined employing Ion chromatography while the cations were analyzed using an Atomic Absorption Spectrophotometer Buck 210 model. The graphical plots in this study were obtained from the results of the chemical concentrations of the analyses. Results of the chemical analysis showed that the wells’ water was low mineralized with chemical concentrations of all ions within approved standard for drinking water except the NO₃^- (mg/L) values with concentrations that range from 95.62 – 405.39 and 13.47 – 382.49 at Ijero-Ekiti and Ado-Ekiti respectively. The Nitrate pollution of water from the two cities came from anthropogenic activities mostly from indiscriminate dumping of waste and fossil fuel. However, Ijero-Ekiti had additional pollutants from the gangues arisen from the mining activities in the area. All the graphical plots (Gibb’s diagram, Schoeller diagram, Wilcox plot and Cross plot) except the Piper diagram indicate that the groundwater at Ijero-Ekiti is more polluted than that of Ado-Ekiti. The Piper diagram for both cities reveals almost equal groundwater rate of pollution with 80% of the groundwater having NaSO₄Cl water type. All estimated irrigation quality parameters (sodium absorption ratio (SAR), soluble sodium product (SSP), Residual sodium Bicarbonate (RSBC), Kelly Ratio (KR), Permeability Index (PI) and Magnesium Absorption Ratio (MAR)) indicate that groundwater at Ijero-Ekiti is more prone to pollution and of better irrigation quality than that of Ado-Ekiti. Despite the high population at Ado-Ekiti, the groundwater is less prone to pollution due to intensive sanitation and hygiene activities. In this study, as against the general accepted view, urbanization has no significant impact on groundwater pollution as hygiene/sanitation is its foremost determinant.