Determination of water quality index and portability of Iguedo stream in Edo state, Nigeria.

Abstract

The water quality index (WQI) and portability of Iguedo Stream in Edo State were determined in this study. The WQI was computed from pH, electrical conductivity, total dissolved solids, chloride, nitrate, sulphate, sodium, magnesium, iron, zinc, copper, lead, manganese, nickel, cadmium and chromium characterized in three designated stations along the stream for a period of six months (January to June, 2014). The Nigerian standards for drinking water quality was used as basis for the computations. With the exception of nickel other physicochemical parameters characterized showed no significant difference (p>0.05) among the stations. Furthermore with the exception of pH and Nickel, the values of the rest of the parameters analyzed complied favourably with Nigerian standards for drinking water quality. The WQI values at stations 1, 2 and 3 were 116.92, 67.22 and 61.87 respectively. These values showed that the water quality at station 1 was poor while stations 2 and 3 were good. Levels of precipitation, weathering and auto-purification capacity of this ecosystem are the natural processes accountable for variations recorded in the WQI values obtained across the stations and study duration. The parameters that most influenced the WQI as depicted by quality rating values include pH, Mn, Ni, Cd and Pb. Application of WQI in this study has been found functional in assessing the water quality of this stream based on the selected parameters.

Key words: Water quality index, physicochemical parameters, Iguedo Stream.