Chemical profile of Nworie River in Owerri, Imo State, Nigeria

Background/Question/Methods

Nworie River is a first order stream that runs about a 5km course across Owerri metropolis in Imo State, Nigeria before emptying into another river, the Otamiri River. Its watershed is subject to intensive human and industrial activities resulting in the discharge of a wide range of pollutants. The river is used for various domestic applications by inhabitants of Owerri. When the public water supply fails, the river further serves as a source of direct drinking water, especially for the poorer segment of the city. Studies of water quality parameters are therefore necessary to determine the extent of pollution so as to monitor likely danger, not only to the human population but also to the aquatic life, hence this study.  They were tested for contaminants with La Motte water pollution detection kits. A total of sixteen (16) water quality parameters were investigated during the month of January 2007, which fell within the dry season in Nigeria. The parameters investigated were dissolved oxygen, carbon dioxide, pH, chloride, nitrate-nitrogen, nitrate, ammonia-nitrogen, hardness, orthophosphate, sulfide, silica, zinc, copper, iron, chlorine, and chromate.

Results/Conclusions

With the exception of dissolved oxygen and carbon dioxide, other chemical parameters did not exceed the water quality standards, suggesting that the river was relatively unpolluted chemically when surveyed. However, the low dissolved oxygen concentrations (1.1 - 3.2 ppm) and high carbon dioxide concentrations (13.0 - 30.3ppm) strongly implicate pollution by organic wastes. Further, the study demonstrated significant longitudinal variations in the water quality parameters along the course of the river, reflecting differences in quality and quantity of pollutants at various locations.  It is recommended that further studies be conducted that include the biological profile of the River and also carried out during the rainy season. The River Nworie needs to be dredged to re-establish its esthetic beauty and cleanliness as well as its recreational and other uses.