Effect of biostimulation and bioaugmentation on hydrocarbon degradation in Antarctic soils

RUBERTO L, LOBALBO A. , MAC CORMACK WP

Villa Carlos Paz, Cordoba, ARG

Congreso; XXXVIII Reunión de SAIB 2002; 2002

SAIB

Bioremediation is an effective tool to improve contaminants degradation in soils. Since temperature is one of the main limiting factors of these processes, only psychrophile microorganisms are adecuate to develope bioremediation techniques in cold areas. Although bioaugmentation has been proposed as the most effective strategy by some researchers, other have found that optimization of physical and chemical factors of soil matrix enhance the hydrocarbon-degrading activity of the natural microflora and make unnecessary the bioaugmentation technique. In this work, we analize the effect of bioaugmentation and biostimulation on the efficiency of in situ hydrocarbon bioremediation. For this purpouse, microcosms were designed (using gas-oil contaminated Antarctic soil) in order to evaluate : abiotic elimination, activity of acthocthonous microflora, biostimulation and bioaugmentation (with bacterial strains and consortia). Viable counts, hydrocarbon-degrading microorganisms, total hydrocarbon concentration (IR spectrometry) and differences in hydrocarbon patterns among treatments (GC-MS) were determined. Changes in aliphatic and aromatic fractions were inferred from p-xylene and tetradecane concentration (GC-MS) wich were used as marker compounds. Biostimulated authocthonous microflora showed high degradation activity (81%), resulting in similar levels compared with those where bioaugmentation were applied. The highest efficiency (86%) was showed by bacterial consortia previously isolated from the same area under study. result showed the feasibility of bioremediation processes in Antarctica and suggested a site specificity of the hydrocarbon-degrading bacterial consortia.