Abstract

This study investigated the effects of effluent discharged from Warri Refinery on the water quality of Ubeji River, Warri Delta state. Water samples were collected from upstream, point of discharge of effluent and downstream sections of the river. Physicochemical parameters (turbidity, pH, electrical conductivity, total dissolved solid, total suspended solid, turbidity, dissolved oxygen, biological oxygen demand, chemical oxygen demand, oil and grease), concentrations of polycyclic aromatic hydrocarbons (PAHS) and heavy metals (Arsenic, Cadmium, Chromium, Nickel, Lead and Zinc) of the receiving water body were determined and compared with the WHO standard for drinking water. At the upstream section of the river, some parameters were higher than WHO standard and these parameters are turbidity, oil and grease, H2S, Chromium, Lead with the mean values 30.5±0.77, 6.96±1.11, 0.64±0.10, 0.039±0.00, 0.005±0.00 respectively. At the point of discharge, pH, TSS, BOD, Chromium, Lead with mean values 6.7±0.08, 48.12±0.28, 12.56±0.34, 0.023±0.00, 0.004±0.00 respectively where found to be above WHO standard. At the downstream section, EC (590.68±2.27), TSS (35.11±0.69), Turbidity (43.22±0.48), DO (51.45±0.04), oil and grease (8.58±0.29), Phenol (5.99±0.03), H2S (0.58±0.01) and Chromium (0.041±0.00), Lead (0.005±0.00) were found to be higher than WHO limit for drinking water. PAHs were found to be higher than the WHO standard at the point of discharge and downstream sections of the river. The concentration of these pollutants indicated that the River is polluted and not good for human consumption. It is therefore recommended that there should be continuous monitoring of refinery effluent.