Evaluation of Surface Water Contamination by Leachate from Uncontrolled Landfills: A Case Study of Yenagoa Central Waste Dump, Nigeria

Recently, surface water pollution has generated grave concerns because of anthropogenic activities including inadequate management of waste. Therefore, this study is concerned with the evaluation of surface water contamination by leachate from uncontrolled landfill in Yenagoa Bayelsa State, Nigeria. Three surface water samples were taken from a stream adjacent to an uncontrolled landfill and analyzed. The Downstream point (SW 1) and Upstream points (SW 3) were taken 50 meters from the southernmost and northernmost ends of the landfill, while the Central point (SW 2) was also taken 50 meters from the central edge of the landfill. The parameters analyzed were, pH, EC, TDS, COD, BOD, TH,NH4+, SO42-, NO3-, Phosphate, Cd, Cr, Cu2+, Pb, Zn, Ca2+, Mg2+, Na+, Fe2+, K+, as well as Total coliform count using standard methods. The concentration of these parameters were compared with NSDWQ and WHO to ascertain their levels within the surface water. The surface water analysis across the Downstream point (SW 1) showed that parameters like pH, EC, TDS, TA, TH, Na, K, Fe, BOD, COD, Phosphate and Total Coliform Count, recorded 7.18, 2,450 μS/cm, 1,225 mg/l, 534.9 mg/l, 270 mg/l, 122.92 mg/l, 69.42 mg/l, 9.48 mg/l, 25 mg/l, 16 mg/l, 7.5 mg/l and 2.80 X 106 cfu/ml respectively. All these values except pH were above NSDWQ and WHO recommended values for potable water. When compared to samples from SW 2 and SW 3, SW 1 samples had higher concentration of parameters. However, some metals and heavy metals like Pb, Cu, Zn, Cd and Cr were below equipment detectable limits for all sampled locations. It was confirmed therefore that the Downstream point (SW 1), was the most contaminated among the three sampled surface water points, in this study. Pearson’s correlational analysis also confirmed that some parameters indicated unity. It was recommended that surface water sources around landfills should be properly monitored to curb water pollution.