Water Quality Variations within the Urban Stretch of a River in Nigeria

The industrial nerve centre of Ogun State is Sango-Otta in Nigeria. It is home to many beverages and other allied factories. The densely populated industrial community is drained by River Atuara, and can be a sanitation concern to users downstream of the urbanized stretch. To stem a possible sanitation issue, this study is purposed to assess the quality of water in the river along its 13km urbanized stretch, which is within Owode – Otta and Gbenga quarters of Sango – Otta in Ogun State, Nigeria. An investigation is undertaken to study the physical and chemical analysis of the quality of water in the river channel to determine its level of pollution. Total Dissolved Solids, TDS, pH, Colour and Temperature measurements were obtained for nine locations on the 21km river stretch. Laboratory analyses were carried out at 4 locations along the water course for the following parameters: pH, Conductivity, Turbidity, DO, BOD, COD, TDS, TSS. Others include Phosphate, Chloride, Nitrate, Sulphate, Cadmium, Lead, Iron, Copper, Zinc, and Nickel. Results indicate that the water quality reduces downstream of the urbanized stretch. Some of the level of heavy metals in the river calls for concern. At Owode, the lead content of 0.11mg/L is too high compared to a maximum of 0.01mg/l permissible, which can cause cancer. This can interfere with Vitamin D metabolism, and can affect mental development in infants. It is toxic to the central and peripheral nervous systems. Cadmium is below 0.002 which is just below the 0.003mg/l permitted in Nigeria. Nickel content was 0.046mg/l between Owode and Ewupe and this is above the maximum permissible level of 0.02 for Nigeria. This has the possibility of carcinogenic health impact. Owode and Ewupe have greater industrial impacts than the other two locations, Igboloye and Gbenga. The trends of each of the 21 parameters from the urbanized stretch of the river have been observed to follow a pattern that can be categorized as similar, mirrored, somersault and composite of mirrored and somersault. More studies were recommended in this direction as well as in determining the locations of factories and industries contributing to the pollution level around Ewupe and their effluent disposal programs will need to be ascertained.