Microbiological Effects of Gas Flaring on Agricultural Soil at Izombe Flow-station, Imo State, Nigeria

Abstract

The microbiological effects of gas flaring on the agricultural soil from Izombe Flow-Station in Imo State were investigated. The physical and microbiological properties of the soil samples were analyzed. The microbiological analysis of the soil samples were conducted by serially diluting and then inoculating the soil samples on different growth media. Several microbiological and biochemical methods were applied in order to isolate and identify the microorganisms accustomed to the soil samples. An unpolluted soil sample from a farmland outside the Flow-Station served as control. The results showed that temperature increased with increase in distance towards the flare while moisture contents decreased as distance increased towards the flare, indicating that flaring exerts adverse ecological effects on the soil. The pH value at the flare site was acidic (4.0) compared with the near neutral obtained from the control (pH 6.8).  Results also showed a decrease in microbial load of the soil samples as distance approaches the Flow-Stack. The total bacterial counts were low (3.0 x 10¹ cfu/g) when compared with 2.9 x 10⁵ cfu/g obtained from the control. The total coliform counts were also adversely affected by the flare. A value as low as 2.0 x 10¹ cfu/g was obtained 10m from the flare stack compared with 6.0 x 10⁴ obtained from the control. The bacteria isolated from the soil samples were species of Staphylococcus spp, Bacillus spp, Escherichia coli, Pseudomona spps, Norcadia spp, Micrococcus spp, Enterobacter spp and Streptomyces spp while species of fungi identified were Aspergillus spp, Fusarium spp, Penicillium spp and Mucor spp. Acid deposition and intense heat from the flare likely have deleterious effects on the soil ecosystem and therefore should be discouraged.

Keywords: Gas flaring, microbiological effects, physical properties, Microbial load, Flow-Station.