ABSTRACT

Studies were carried out to evaluate the changes that occur in the ecosystem of Owaza as a result of oil spillage from pipeline. Four different sites were selected the heavily spilled area, moderately spilled area, the lightly spilled area and the fourth area was at non spilled area which serves as the controlled experiment In each of these areas 100 x 100m was demarcated and a 100m transect was divided into plots of 10 x 10m and four were selected at random from each block for detail study. Soil samples were collected and taken to the laboratory for airdrying processing and analysis by standard methods. Water samples were collected and analyzed. The result obtained showed that the amount of mineral composition released to the soil was within the acceptable limit, established for mineral - soil environment (World Health Organizion 1984 and Federal Environmental Protection Agency 1988). The result of analysis of variance for mineral elements (copper, chromium and manganese) shows that their effect varied significantly with location but did not vary with depth at (p>0.05), while the effect of other mineral elements (iron, cadmium and vanadium) were not significant both at location and depth. The percentage organic carbon and base salination were high, exceeding the maximum tolerable limit of 20% and 80% respectively (World Health Organizion 1984 and Federal Environmental Protection Agency 1988). The total hydro carbon released into the soil was high with the mean (400mg/kg‘1). The pH of both soil and water varied between 4.80 and 5.10 with a mean of 4.95 and 7.0 - 7.8 with a mean of 7.4 respectively. While the analysis of variance showed that the effect of organic carbon, available phosphorous, exchangeable acidity, sodium and nitrogen varied significantly with location but did not vary with depth at (p>0.05). The effect of pH electrical conductivity and effective cation exchange capacity are not significant both at location and the depth. Total Hydrocarbon in the water sample ranged from 8.9 - 120mg/l with a mean value of 64.45mg/l which is above the maximum tolerable limit of 10mg/l indicating pollution, while the underground water analysis did not detect any Total Hydrocarbon. The vegetation of the area showed yellow coloration and withered while the grasses died because of the oil toxicity. It is recommended that since bunkering is active in the Niger Delta region, adequate contingency plans shall be made to cope with any accidental spills from companies. The clearing of vegetation shall be kept to the barest minimum