Abstract
An investigation was made of the sources and degree of pollution of Ogunpa Lake, situated in Ibadan, Nigeria. It was shown that the lake receives a variety of waste effluents from domestic and industrial sources which discharge into the Ogupa stream. These waste effluents have caused an odour nuisance in the lake, and little or no dissolved oxygen is present. The discharge of nutrients (N and P) to the lake has resulted in excessive growth of aquatic weeds. All these impacts on the lake have resulted in a reduced fish production. Some suggestions for the prevention of pollution and the recovery of the lake are presented.