Microbiological And Physicochemical Analyses Of Oil Contaminated Soil From Major Motor Mechanic Workshops In Benin City Metropolis,Edo State, Nigeria

Abstract

The ability of microorganisms to utilize used oil in contaminated soil from some selected major mechanic workshops in Benin City metropolis as sole source of carbon and energy was studied. Soil samples collected from the three major mechanic workshops at Igun, Evbareke and Uwelu Quarters in Benin City were analyzed for the microbiological and physicochemical qualities using the basic microbiological methods. The total heterotrophic bacterial counts from the three mechanic workshops ranges from 1.98 X 107 to 2.95 X 10⁷cfu/g while the total heterotrophic fungal counts ranges from 6.7 X 10⁶ to 9.2 X 10⁶ cfu/g. The hydrocarbon utilizing microbial isolates were isolated using the Bushnell Haas enrichment techniques. The hydrocarbon utilizing microbial populations were recorded to range from 3.1 X 10⁶ to 9.7 X 10⁶cfu/g and 3.4 X 10⁶ to 6.0 X 10⁶ cfu/g for the bacterial and fungal counts respectively. The bacterial isolates include the genera Bacillus, Pseudomonas, Microococcus, Flavobacterium, Klebsiella, while the fungal isolates include the genera Aspergillus, Penicillium, Fusarium, Trichoderma and Yeast. The biodegradation potentials of the hydrocarbon degrading microbial isolates monitored by gas chromatography (GC) showed Pseudomonas sp. and Aspergillus versicolor to have recorded the highest biodegradation potentials among the microbial isolates. The frequency of occurrence of the microbial isolates revealed the microbial isolates Pseudomonas sp., Bacillus sp., Microococcus sp., Aspergillus versicolor, Trichoderma sp and Penicillium sp. as the most frequently occurring isolates. The physicochemical properties of the soil samples analysed shows the pH ranges from 5.63 to 6.01, percentage of carbon 2.345 to 4.800, total organic matter 1.59 to 7.81%, total petroleum hydrocarbon 86.10 to 286.50 mg/kg and sulphate 1.49 to 6.10ppm. The correlation analysis showed that there was significant difference in the mean values for both total heterotrophic bacterial and fungal population among the locations. It was also showed that there exist significant difference in the optical density and pH among the microbial isolates. @JASEM

Keywords: Oil contaminated soil, microbial isolates, mechanical workshops and physicochemical parameters

J. Appl. Sci. Environ. Manage. Dec, 2011, Vol. 15 (4) 597 - 600