Spatial and Temporal variations in Water Quality of River Ogun, Abeokuta, Ogun State, Nigeria

Abstract

Rivers have always served as a source(s) of domestic water as well as dumping sites for many households in communities. The water quality of River Ogun is contaminated largely through the activities of the population by the latter purpose. Several studies have been carried out on water quality assessment with little or no information on the River Ogun portion of Abeokuta, a fundamental water source for densely populated area. Thus, the need for this study. Water samples were obtained four times from all sampling sites (7) by field survey for four (4) months (September 2019 - December 2019), resulting in a total of 28 samples. Standard analytical methods were undertaken to determine the physical (salinity, temperature, Electrical Conductivity (EC) and Total Dissolved Solids (TDS)), and the chemical parameters (pH, hardness, ammonia, chloride, nitrate, alkalinity, dissolved oxygen, and biochemical oxygen demand). Graphs, tables, T-test, and ANOVA, were employed for the statistical analyses. Analysis of variance [Fcalculated (0.25) < F-tabulated (2.22)] at α showed no significant variations in the water quality parameters of the 0.05 river across the sampling sites. The T-test [T-tabulated (2.57) > T-calculated (1.36)], also showed no significant variations in the mean values of the water quality parameters and WHO-recommended standards. The study though, showed that the values of most of the physiochemical parameters meet the WHO-recommended standards. However, the water quality index calculated showed the River Ogun poor water quality status, and thereby, making it unsuitable for domestic consumption despite meeting the WHO recommended limits. The study therefore, suggested continuous water quality monitoring to keep track of the quality status of the river.