Nature holds no spite. It even proves a precious ally when it comes to treating sites polluted by industry rejects, agricultural or urban activity or waste disposal. Within the BIOGECO* laboratory, researchers in the “Communities Ecology” team have understood this and they develop solutions based on biodiversity and the tolerance levels of plants.
p until one started using plants and the micro-organisms present in their roots, there existed only two ways to depollute a soil: either carry away the contaminated soil to another site and treat it through a physicochemical process, thus creating new waste, or cover it with healthy earth sampled elsewhere. The problem was displaced, not solved. Now fully developed, the phytoremediation techniques developed by the “Communities Ecology” team provide “green” solutions for certain soil and water pollutions. Like for instance a site with excess amounts of trace elements, whether non-essential (arsenic, cadmium) or essential (copper). A promising lead consists in selecting plant varieties tolerating the targeted pollution and able to root it out from the soil
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and stock it in their airborne parts. Techniques such as hydrothermal oxidation – explored in collaboration with the ICMCB* – valorize biomass, while co-producing energy with no Co2 emittance and recycling trace elements as well. Another potential solution tested by Michel Mench consists in producing sunflower oil for biofuel while picking up excess metals like copper in the soil. Short rotation coppices and graminates also allow to neutralize copper and to prevent its dissemination. While giving new life to polluted sites, green solutions reduce health risks and favor bio diversity.
BIOdiversité, GEnes and COmmunities [ BIOGECO ]
Scenarios For each site, researchers draw up remediation scenarios derived from the sampled contaminants and the client’s priorities. These scenarios use plant techniques – stabilization or extraction – applied to soils and more recently, to the water sources present as well. In certain areas, these techniques may be combined with older non-vegetal methods. International Interest A member of the International Society of Trace Elements Biogeochemistry (ISTEB) and of the COST 859 European Cooperation (numbering 250 researchers in 29 countries), Michel Mench is at the heart of a worldwide active network. The Bordeaux team’s expertise is renowned in three phytoremediation areas: genes and plants, low vegetal canopy and long-term site planting.
A constant and global support The Aquitaine Regional Council finances phytoremediation projects on a regular basis, through laboratory equipment (150,000 € from 2004 to 2007; 10,000 € in 2009), or thesis grants (40,000 € in 2006; 44,000 € in 2009).
BIOGECO “Communities Ecology” team INRA - University Bordeaux 1 Sciences and Technologies Talence - ✆ 05 40 00 31 14 http://w3.pierroton.inra.fr/biogec o/ecologie
* BIOdiversity, GEnes and COmmunities.
MADE IN Aquitaine research
* Condensed Matter Chemistry, Bordeaux Institute.
10 portraits of research - Édition 2009
UNION EUROPEENNE
Cap Sciences publication - Editing: Donatien Garnier - Translation: Emmanuel Potts - Photos: Frédéric Desmesure - Graphic design and réalisation: Lisa Morand
From the roots up!