ABSTRACT

The purpose of this study is to isolate and identify microorganisms associated with diesel contaminated soils. A total of four (4) soil samples were collected from four diesel-soil contaminated sites and the control soil was collected from the top soil, process and cultured in the laboratory using pour plate technique. Some major bacterial and fungal isolates were identified using several biochemical and physiochemical techniques. these includes: Bacillus spp, Staphylococcus aurues, Escherichia co/i, Kiebsilla spp, Micrococcus spp, Aspergillus niger, Aspergillus Jiavus, Rhizopus stolonizer. Amongst the four diesel contaminated soil samples investigated within Umuahia metropolis, sample B had the highest bacteria count 6.4 x 10⁹ followed by sample A (5.8x 10⁹), sample C (4.0 x109), while the least bacteria count was recorded on sample CT (1.7 x10⁹). The total fungal plate count investigated on the diesel contaminated soil samples, reveals sample C as having the highest fungi count (4.8 x109) and sample A having the least fungi count (1.0 x 10⁹). From the findings in this study, it was observed that Escherichia coli and Staphylococcus aureus are the most frequently occurring isolates with a percentage occurrence of 27.7% each, followed by Klebsella spp 16.6% BaciIius  spp 16.6% Micrococcus spp 11.1%. The diesel had no significant effect on the soil organic carbon, total nitrogen and available phosphorus. However, values recorded for available Phosphorus under the soil contaminated with diesel were higher than the initial value observed. In conclusion, the results of this study confirmed the presence of microorganisms in soils contaminated with diesel, hence many have the ability to metabolize the hydrocarbon.