Abstract
Soil provides home and food to both plants and organisms when it is not altered by any materials that make it unfavourable for the growth of species. Characterization of Bacterial species in oil-contaminated soils was conducted. Five soil samples were collected from five (5) selected petroleum mega stations namely, A.A Rano, NNPC, Ap 2, Oando and Yahaya Mekera all within Birnin Kebbi, Kebbi State. The species of bacteria were enumerated and classified using serial dilution, standard plate count and biochemical tests. From the results of the bacterial analysis, six (6) species of bacteria were encountered from the contaminated soil samples collected and these were Bacillus cereus which had the highest rate of percentage occurrence with 6 (30%) while Yersinia enterocolitica, Closteridium tetani and Staphylococcus aureus had the lowest, each with 2(10%) others are Pseudomonas aeruginosa 3(15) and Bacillus subtilis 5(25). The total mean of the bacterial counts from soil samples analyzed in this study ranged from 8.75 x 106 cfu/g to 9.45 x 106 cfu/g. Based on petroleum stations, NNPC had the highest bacterial load of 9.45 x 106 cfu/g, while A.A Rano had the lowest bacterial load of 8.75 x 106 cfu/g. There is a need for concern over human health risk that could be related with some of these bacterial isolates that are pathogenic species in our environment. Therefore, public enlightenment, good environmental hygiene and prevention of oil spillages on the soil could provide a solution to soil contamination problems in our petroleum stations.

Key words: Soil, bacteria, percentage and petroleum stations