Effects of effluents from a sewage treatment plant on the aquatic organisms

The effects of sewage pollution on the distribution and abundance of some orgnanisms over a period of 4 mo at the Ahmadu Bello University Main Campus sewage treatment plant and Kubanni river were studied. Physico-chemical parameters such as dissolved oxygen; temperature; hydrogen ion concentration (pH); electrical conductivity and chemical oxygen demand influenced by pollution were measured with respect to the population of aquatic organisms. The organisms were used as biological indices to monitor the ecological imbalance caused by the effluent. The variations in concentrations of some heavy metals were also measured. The studies revealed that at the source of pollution there were no organisms except for some insect larva such as Eristalis, Psychoda, and some microscopic algae like Oscillatoria, Anaebaena, and Polysystis. A location (site 5) on Kubanni river just before the confluence of the sewage effluent and the river was taken as the control. There was a wide variety of organisms (crustaceans, rotifers, and fish) at the control point.