The Effect of Refinery and Petrochemical Effluent on Water Quality of Ubeji Creek Warri, Southern Nigeria.

Abstract

This study investigated the effects of treated effluent discharge on the water quality of Ubeji Creek, Warri. Water and sediment samples were collected from upstream and downstream sections of the creek. Physicochemical parameters and concentrations of heavy metals of the receiving water body (upstream and downstream) were compared with that of the treated effluent. Recorded mean pH values of the effluent, receiving water body and sediment were 6.26 ± 0.04, 6.90 ± 0.06 (upstream), 6.87 ± 0.01 (downstream) and 6.54 ± 0.44 respectively. Electrical conductivity ranged from 1150.41 ± 0.01 – 151.50 ± 0.71μS/cm for water samples and mean value of 1870.00 ± 1117.23μS/cm for sediment. Total hydrocarbon (THC) and total dissolved solids (TDS) varied from maximum values of 8.81 ± 0.01 – 2.83 ± 0.04 mg/l and 575.15 ± 0.07 – 75.72 ± 0.26 mg/l respectively. Nitrate and phosphate level was observed to be higher in the sediment (45.30 ± 3.96 mg/l and 9.62 ± 2.57 mg/l respectively) than the level obtained for upstream (0.35 ± 0.01 and 0.01 ± 0.00 mg/l) and downstream (0.25 ± 0.03 and 0.01 ± 0.00 mg/l). The ranges for exchangeable ions were; Na (7.73 ± 0.24 – 6.61 ± 0.24 mg/l), P (5.26 ± 0.04 – 2.25 ± 0.03 mg/l), Ca (34.74 ± 0.09 – 13.45 ± 0.33 mg/l) and Mg (2.74 ± 0.18 – 1.80 ± 0.06 mg/l) for water samples; for the sediment, the range is 36.33 ± 2.50 – 2.76 ± 0.96 (Na > P > Ca > Mg). The levels of heavy metals (Lead (Pb), Zinc (Zn), Copper (Cu), Iron (Fe), Chromium (Cr), Arsenic (As), Nickel (Ni), Vanadium (V), and Cadmium (Cd)) in water samples and sediment were estimated using Atomic Absorption Spectroscopy. The results obtained, ranges from Fe (4.29 ± 0.00 – 2.76 ±
0.03) to Pb (0.01 ± 0.01 – 0.01 ± 0.00) for water samples and Zn (9.40 ± 1.50) to Cd (0.05 ± 0.00) for sediment. This value obtained for sediment was observed to be higher than that in the water samples.

Keywords: Effluent discharge, water quality, sediment, Heavy metals.