Impact Assessment of Gas Flaring on Soil Bacterial Community Structure and Physicochemical Property in Nigeria

Authors: Wemedo SA* and Appah MO

DOI: 10.23880/oajmb-16000165

Volume 5, Issue 2

Abstract

Gas flaring is the wasteful emission of hydrocarbon gases into the atmosphere; it is routinely used to dispose flammable gas that either is assumed unusable or uneconomical to recover. The burning of the wasteful gas has been shown to have significant environmental consequences. Therefore, this study was designed to determine the impact of gas flaring on soil bacterial spectrum and its physicochemical property. Soil microbiological quality was investigated using culture techniques while physicochemical property of the soil was analyzed using standard analytical procedures. Results obtained showed that pH and Av. phosphorus decreased from 5.80 and 8.86mg/kg in control soil to 5.40 and 6.50mg/kg in flared soil respectively. Electrical conductivity and total organic carbon increased from 100μS/cm and 0.20% in control soil to 160μS/cm and 0.63% in flared soil respectively. Total nitrogen slightly increased from 0.01% in control soil to 0.02% in flared soil. Soil textural class was sandy-clay-loam for both control and flared soils. Mean counts of bacteria increased from 4x103cfu/g in SD50m to 2.0x104cfu/g in SD100m, 3.1x104cfu/g in SD200m, 4.5x104 in SD300m to 4.8x105cfu/g in control soil. All the bacterial species were isolated from control and SD300m soils except Acinetobacter and Microbacteriun species which did not occur in SD300m soil. Six (6) organisms: Bacillus, Corynebacterium, Pseudomonas, Paenibacillus, Pusillimonas and Salinicoccus species were isolated from SD50m soil. The number of bacterial genera isolated increased to eleven (11) in SD100m soil with Cronobacter, Enterobacter, Escherichia coli, Kluyvera, and Microbacterium species added to those of SD50m soil. Fifteen (15) organisms occurred in SD200m soil as Acinetobacter, Arthrobacter, Brevibacterium, Klebsiella, Rathayibacter and Staphylococcus species were added. This study revealed that gas flaring decreased bacterial population in soil in close proximity to the flare point; the effect being reduced as the sampling distance from the flare point increased. Some physicochemical parameters decreased in flared soils and others increased when compared with control soils. Gas flaring selectively inhibited soil bacteria with more species occurring in soils farther away from the flare and soil closest to the flare point having less numbers of bacteria. In conclusion, gas flaring had negative impact on soil bacteria and varied effect on physicochemical properties of the soil; in this way soil fertility could have been hampered. Oil and gas companies as well as government agency need to adopt measures that would curb unnecessary gas flaring in Nigeria by putting the flared gas into economic use.

Keywords: Impact Assessment; Gas Flaring; Soil, Bacteria; Physicochemical; Community Structure

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