Investigation of water quality of two rivers in Agbede –Wetlands in Southern Nigeria

Water quality of Edion and Omodo Rivers were assessed chemically from March to October, 2010. The abstracted water samples were also subjected to bacteriological examination. The Rivers were each sampled at upstream and downstream locations. Twenty (20) physico-chemical characteristics which included heavy metals were determined in the laboratory. Air temperature ranged from the mean 30.69 to 31.38 °C, water temperature 26.50 to 27.00 °C, pH 7.05 to 7.15, electrical conductivity 7.99 to 25.55mScm^-1, turbidity 24.11 to 54.65FTU, total dissolved solids 6.14 to 7.78mgl^-1, total hardness 25.10 to 30.38mgl^-1, chlorine 22.06 to 25.02mgl^-1, BOD₅ 0.88 to 2.42mgl^-1, DO 3.81 to 6.50mgl^-1 and the nutrient elements such as  sulphate,  phosphate and Nitrate ranged between 0.03 and 3.81mgl^-1, sodium 1.87 to 3.81mgl^-1 and potassium 1.08 to 1.27mgl^-1. Heavy metals levels were low, ranging from 0.0025 to 5.6650mgl^-1 (Copper 0.0350 to 0.0910mgl^-1, Iron 0.2825 to 0.5112mgl^-1, cadmium 0.0015 to 0.0104mgl^-1, lead 0.0025 to 0.0230mgl^-1, zinc 2.7013 to 5.6650mgl^-1 and chromium 0.0025 to 0.0263mgl^-1). Conductivity, sulphate, zinc and fecal coliform count showed significant difference (P<0.05) with low values indicating good water quality. Water Quality Index (WQI) revealed that Stations 2 and 4 respectively had good water quality. All the characteristics had their values within FEPA Limit except for Zn (> 3.0mgl^-1).