Cinétiques de désorption des composés organiques hydrophobes pour différents sédiments dragués contaminés

auteurs

• Charrasse Benoit
• Hennebert Pierre
• Doumenq Pierre

type de document

résumé

Dredged contaminated sediments are considered as waste and landfilled. Reuse in public works is considered. The environmental impact must be assessed, and in particular the emission of persistent organic pollutants (POPs) in percolating water. The kinetics of desorption of POPs from soil or sediment particles is important both from environmental and analytical points of view. Desorption rates of POPs are important in predicting the transport of these compounds between different environmental media, their bioavailability, and the effect of remediation processes at contaminated sites. It has been shown that a large part of POPs (generally over 50 %) are strongly adsorbed to the condensed organic matter (char or soot - also called black carbon) with very slow desorption kinetics. However, today the risk assessment and the regulations are based on the total POPs content. For high contamination, reuse is there from not allowed (in fill, building materials, bricks, and mounds). A kinetic desorption approach could reassess management of contaminated materials taking into account the labile (rapidly-desorbed) fraction instead of the total POP content.

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