Physico-chemical water quality assessment of two rivers in Ogun State, Nigeria

The purpose of this study was to evaluate the River Afa and River Owo's water quality in order to gather information that may be used in the near future to formulate control strategies. Water samples were collected from two sites (upstream and downstream) on the River Afa and from four stations located along the course of River Owo to covered both rainy and dry seasons. Twenty-two (22) important parameters were selected for physico-chemical water quality analysis. Samples collected were analysed using appropriate standard techniques. Generally, pH, TDS, alkalinity, acidity, hardness, and EC recorded higher mean values in River Afa than River Owo. However, Organic matter (OM) and total organic carbon (TOC) recorded higher mean values in River Owo. Nitrate and sulphate had higher mean values in River Afa compared with River Owo. The results were compared to World Health Organization (WHO) and Nigeria Standard for Drinking Water Quality (NSDWQ). As a result, most of the parameters examined were below the recommended safe drinking water threshold. However, the turbidity and surface water temperature were above WHO and NSDWQ standards. Comparison of data obtained between water quality parameters was made using cluster analysis at P≤0.05 and this revealed significant relationship among the parameters measured. The majority of the water quality parameters that were monitored in this study showed higher values in River Afa than in River Owo. Also, results of te monitored water quality parameters showed that both River Afa and River Owo water may pose danger to health if consumed untreated and requires further purification process to prevent imminent water-related diseases befallen the residents of the area.