The microbiological and physicochemical characteristics of soil contaminated with used generator oil were carried out. The media used were nutrient agar, Sabouraud dextrose agar mineral salt agar and mineral salt agar with antibiotics for the isolation of total heterotrophic bacteria total and fungi, hydrocarbon- utilizing bacteria and fungi respectively. The pour plate technique was employed. The total heterotrophic bacterial count ranged from 3.7 x 106cfu/g to 9.7 x 106cfu/g while the total heterotrophic fungal count ranged from 3.0 x 105cfu/g to 6.7 x 105cfu/g. The hydrocarbon-utilizing bacterial count ranged from 2.5 x 104cfu/g to 3.7 x 104cfu/g. The hydrocarbon-utilizing fungal count ranged from 1.5 x 103cfu/g to 2.4 x 103cfu/g. The microorganisms isolated were Bacillus species, Klebsiella species, Micrococcus species, Pseudomonas species, Aspergillus species, Candida species, Mucor species and Penicillium species The result of the physiochemical parameters ranged as follows pH, 3.9 – 4.7; conductivity, 118µs/cm to 159 µs/cm; total organic carbon, 19.85% to 26.10%; oil and grease, 420mg/kg to 1700mg/kg; total petroleum hydrocarbon, 386mg/kg to 1625 mg/kg; phosphate 2.41mg/kg to3.54mg/kg; sulphate, 12.80mg/kg to 19.40mg/kg; nitatre,1.53mg/kg to 2.91mg/kg; lead 0.63mg/kg to 1.62mg/kg; total iron, 36.7mg/kg to 63.1mg/kg; copper 1.52mg/kg to 3.04mg/kg; nickel, 0.081mg/kg to 0.083mg/kg; cadmium, 0.031mg/kg to 0.099mg/kg; manganese, 6.87mg/kg to 10.14mg/kg; barium, 0.03mg/kg to 0.102mg/kg; sodium, 15.8mg/kg to 23.8mg/kg; manganese, 1.80mg/kg t0 4.70mg/kg; potassium, 3.12mg/kg to 7.05mg/kg and calcium, 129mg/kg to 182mg/kg. It has been observed that the used generator oil had impacted negatively on the soils within the vicinity of the generating plants.
