River Owo is a polluted water body in Agbara Industrial area an outskirts of Ojo Local Government Area due to the dumps of industrial wastes. The body contains diverse soluble and insoluble both of organic and inorganic compounds as well as living organism such as benthic macroinvertebrate fauna. This research work is an intensive studies carried out on constituents of river and compared with Iba stream of no active polluting activities in the same Local Government as a control. Water and macro invertebrate samples were taken from the two sites. Physicochemical and heavy metals analysis were carried out on the water using Atomic Absorption Spectrophotometer. The invertebrates were quantitatively and qualitatively analyzed. I nvestigations revealed that the water body is slightly acidic with pH of 5.5 to 6.5. It hardness have been mild due to the impact of the constituents that have softened it to extents of about 88mgL -1 . Sulphate level of range 0.07 to.09mgL-1 is significantly low. These physicochemical factors did not contribute adversely to the two water bodies. However, high BOD of 340 to 357 above the limit 30 indicated that the pollution of River Owo mainly comes from organics waste dumps. Decapods such as Palaemonetes sp and amphipods which are common to polluted environment are found in River Owo. The abundance of various forms of insects of which dragon fly nymph Palemonetes sp were most in population are found around River Owo. Therefore River Owo is mainly being polluted with organics substances. However both Physicochemcal parameters and Benthic studies Iba stream indicated that it is free of pollution. This could have been due to the disallowed dumps of domestics and industrial wastes were not allowed into the stream.
