Oil biodegradation: quality assessed monitoring of soil microbial
populations on a 25-year old landfarming site for oil refinery waste
Leena Suominen, docent (environmental biotechnology), university lecturer (pedagogy of higher education), present position at Faculty of agriculture and forestry
P.O. Box 62, 00014 University of Helsinki, email: leena.suominen(at)helsinki.fi
Kaisa Wallenius, Anu Mikkonen, Kaisa Lappi.
The basic aim of this work is to recover and bring ecological balance to contaminated environment Several thousand oil-polluted sites that exist in Finland constitute a significant ecological and socio-economic problem. Many areas of industry have met a turning point in the handling of low/medium contaminated waste on year 2007 as the new directive of European Union has closed a major proportion of old and insufficiently equipped dumping grounds. Applicable in situ treatment technologies will be of dire demand, as will the tools to accurately and cost-effectively evaluate the efficiency of these softer technologies.
The contamination level of most of the polluted sites is relatively low and thus the costs of the most efficient cleaning techniques exceed the expected benefit. Bioremediation refers to cost-effective and potential biological cleaning methods of contaminated sites. One promising technique for in situ bioremediation is rhizoremediation, in which microorganisms inhabiting the rhizosphere of a plant degrade the pollutant.
The rhizoremediation approach for the cleaning of oil contaminated soils is safe, it does not produce exess of organic nitrogen in soil and thus does not induce eutrophication in the surrounding rivers. It includes possibility for integrated bioproduction. The cultivation of energy plants (e.g. reed canary grass, energy willow), use of which is only in Finland to be increased by tenfold by the year 2015, may be of great significance in more densely populated areas. The potential of Galega orientalis to be cocultivated as a nitrogen source for other plants needs to be evaluated in the near future.
In the Bioremediation project we study the following topics:
- The structure and dynamics of microbial oil degrader populations in oil-polluted soil.
- Applicability of Galega rhizoremediation for the treatment of oil contaminated boreal soil.
- The taxons and metabolic pathways relevant to anaerobic biodegradation of oil hydrocarbons.
- Targets for development in methods and sample handling in the monitoring process of contaminated soils.
Suominen, L., M.M. Jussila, K. Mäkeläinen, M. Romantchuk and K. Lindström. 2000. Evaluation of the Galega-Rhizobium galegae system for the bioremediation of oil-contaminated soil. Environmental pollution 107: 239-244.
Lindström, K., M.M. Jussila, H. Hintsa, A. Kaksonen, L. Mokelke, K. Mäkeläinen, J. Pitkäjärvi and L. Suominen. 2003. Potential of the Galega – Rhizobium galegae system for bioremediation of oil-contaminated soil. Food Technol. Biotechnol. 41, 11-16.
Suominen, L. 2000. Molecular biology of symbiotic interactions between Galega orientalis and Rhizobium galegae. Doctoral dissertation. University of Helsinki.
Kaksonen, A.H. , M.M. Jussila, K. Lindström and L. Suominen. 2006. Rhizosphere effect of Galega orientalis in oil contaminated soil. Soil Biology and Biochemistry, 38, 817-827.
Jussila, M., G. Jurgens, K. Lindström and L. Suominen. 2006. Genetic diversity of culturable bacteria in oil-contaminated rhizosphere of Galega orientalis. Environmental Pollution 139:244-257 (PDF).
Jussila, M.M., Z. Ji, L. Suominen and K. Lindström. 2006. TOL plasmid transfer during conjugation in vitro and rhizoremediation of oil compounds in vivo. 146 (2007), s. 510-524.
Suominen, L., E. Kondo, K. Lappi, A. Mikkonen, K. Wallenius and K. Lindström. 2005. Monitoring rhizoremediation process of fuel oil polluted soil. In e-proceedings of 3rd European Bioremediation Conference. 4 Jul 2005 - 07 Jul 2005 Chania, Crete Department of Environmental Engineering, Technical University of Crete
Jussila Minna 2006. Molecular biomonitoring during rhizoremediation of oil-contaminated soil. Doctoral dissertation. University of Helsinki.