Evaluation of water quality parameters of the Okhuaihe River, Edo State, Nigeria

Abstract

Information gotten from water quality monitoring is useful in the management of water resources. The water quality of the Okhuaihe River, Edo State, Nigeria was investigated from October 2016 to June 2017 to determine its fitness for drinking and usage for domestic purposes. Water samples collected from four stations were tested for thirty-two physicochemical parameters using standard analytical procedures. Most of the parameters determined were within the acceptable limits permitted by the World Health Organization and Federal Ministry of Environment for potable drinking water and domestic usage, except for Colour, Biological Oxygen Demand, Iron, Cadmium and Lead, which exceeded the accepted limits of the set standards. High significant difference (P < 0.01) occurred in Nitrite, Biological Oxygen Demand, Water temperature, Cadmium and Total Hydrocarbon Content, while Sodium was significantly different (P < 0.05) across the stations. Duncan Multiple Range Test revealed that station 4 was the cause of difference for water temperature, while station 3 was the cause of difference for Biological Oxygen Demand, Nitrite, Sodium, Cadmium and Total Hydrocarbon Content. All other parameters were not significantly different (P > 0.05) across the stations studied. Temporal analysis showed variations in the wet and dry seasons period, for all parameters studied. WQI obtained from the four stations are 17.01 (Station 1), 13.29 (Station 2), 14.54 (Station 3) and 13.24 (Station 4). The values fell within the permissible limits (< 50) for excellent drinking water. This indicates that the water body is excellent for human consumption, aquatic life and other domestic purposes. PCA results showed that four major components controlled the water quality of the river, with Eigen values > 1 accounted for 83.802% of the total variance. Although the quality of the water from the Okhuaihe River is suitable for drinking and domestic usage, regular monitoring of human activities along the waterfront and control of effluents discharged into the river by regulating authorities is recommended to sustain and improve water quality.

Keywords: human activities, physicochemical parameters, water quality index, principal component analysis