Physicochemical and Microbiological properties of soil in Ahoko: A Suspected Petroleum Bearing Site (SPBS)

Abstract

Microbial surface prospecting is a vital process in the exploration of hydrocarbon suspected site, as a result the aim of this study was to assess the microbial and physicochemical properties of soil in a suspected petroleum bearing site at Ahoko, Kogi State, Nigeria, to ascertain the potent site for exploration using the presence of microbial anomalies. The four identified sites; A, B, C and D were mapped and gridded. Soil samples were collected from each of the sites and analysed for physicochemical properties, culturable heterotrophic aerobic bacteria, total fungi and distribution of specific hydrocarbon oxidizing microbes. Physicochemical properties showed that pH of the sites were within the range of 5.30 to 7.05. Site A had the highest total organic carbon (1.18%), conductivity (12.0 ± 3.50 μ∫/cm), available Phosphorus (12.06 ± 0.00 mg/kg), base saturation (66.03 ± 0.00%) and exchangeable acid (2.28 ± 0.58 cmol/kg) compared to other sites. The aerobic heterotrophic bacteria in the soil varied with respect to the month of sampling/site at the range of 0.38 x 106 CFU/g to 2.88 x 106 CFU/g. Total number of culturable fungi ranged from 1.27 x 103 CFU/g to 11.0 x 103 CFU/g. Site A had the highest number of methane and ethane oxidizing microbes. Site C showed the highest number of propane oxidizing microbes of 1.15 x 102 CFU/g while C had the least, 0.04 x 102 CFU/g. There was little or no growth of butane oxidizing microbes in all the sites. The study revealed the presence of high concentrations of hydrocarbon oxidizing bacteria in Ahoko area of Bida basin. Site A had higher popul