Water quality parameters in the major rivers of Kainji Lake National Park, Nigeria

This study examined the physical and chemical properties of waters of the major rivers in Kainji Lake National Park for a period of twenty four months. The implications on the public health and aquatic organisms were also determined. The major rivers include; Oli, Manyera, Nuwanzurugi, and Poto. River Oli was sampled at the hippo pools at Kilometers 8 and 12 and two animal drinking points. Other rivers were sampled at two animal drinking points. Standard methods were used to monitor the physical and chemical parameters. Physical parameters that were considered include; temperature, colour, total suspended solid and turbidity. The chemical parameters include hardness, chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved oxygen (DO), iron, manganese, calcium, chloride, nitrate, pH, phosphate, ammonium and electrical conductivity. Seasonal variation appeared to have influence on the physical and chemical parameters. Statistical analysis shows that there were significant differences between sampling points and locations mean values for the different physical and chemical parameters examined. The presence of hippopotamus affected some parameters such as BOD, DO, COD, pH and turbidity significantly. The BOD and COD were strongly, significantly correlated and positively correlated (r = 0.757, P≤0.05). The ammonium and nitrite contents are not significantly correlated but positively and weakly correlated (P<0.05, r = 0.141) between the dry seasons and wet seasons mean values.Key words: Water quality, Oli River, River Nuwanzurugi, River Manyera, River Poto