Quality assessment and classification of Ogbese river using water quality index (WQI) tool

water parameters were considered for the Ogbese river quality assessment and water quality index (WQI) tool to classify it and to see if it required treatment before usage. Samples from 20 points at 50 ms interval were collected in February and June 2013 representing dry and wet seasons, respectively, and in accordance with American Public Health Association, APHA (Publications on standard methods for the examination of water and wastewater, pp 123-189, 2005) standard procedures. Most of the parameters were within maximum permissible limits of the World Health Organization (WHO), Food and Agriculture Organization (FAO) and Nigeria Standards for Drinking Water Quality (NSDWQ) with the exception of total dissolved solid, turbidity, electrical conductivity and total coliform in both seasons. Lead, zinc and iron were not detected in dry season, while their traces were recorded in wet season. WQI indicated considerable degrees of pollution with classification numbers of 46.61 and 44.91 for dry and wet seasons, respectively, and falls within Class IV of the general rating scale.