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Procédé de phytoextraction couplé à la bioaugmentation d'un sol agricole polycontaminé par du chrome, du mercure et du plomb

Abstract : Agricultural soils have been contaminated for many years by both direct pesticides and fertilizer supplies, and indirect contaminations originated from industrial activities. The agricultural soil used in the present study was collected in the Thur valley (Haut-Rhin, France), and contains chromium (488 mg/kg), mercury (13 mg/kg) and lead (381 mg/kg). Phytoextraction is a soft-cleaning technology, cost-effective and non-destructive for biological life in soil. Nevertheless the low availability of metals in soil along with the slowness of the phytoextraction rocess represent limiting factors that are likely to reduce its efficiency. A new technology named rhizoremediation, which associate bioaugmentation and phytoremediation, was tested in this study in order to enhance the phytoextraction rate. Our results showed that Cr and Pb availability in soil was enhanced, as the result of the bioaugmentation of soil with microorganisms producing siderophores, especially with the Pseudomonas species. The siderophore production with Pseudomonas species was optimized with the addition of carbon substrates. Immobilization of bacterial cells in Ca-alginate beads supplied with skim milk enhanced the siderophore production in a metal-containing media and improved the bacterial survival in soil. More than 90% of Cr, Fe and Pb and more than 40% of Hg were adsorbed onto Ca-alginate beads surface, which decrease metal toxicity for immobilized or free cells, and create an iron deficiency inside the beads, which enhanced siderophores production by microorganisms. The selected icroorganisms were inoculated in the contaminated soil, with maize as a model plant. The bioaugmentation of soil pots with immobilized cells of P. aeruginosa and skim milk enhanced the amount of metal accumulated in leaves by a factor of 5.4 and 3.8 for Cr and Pb respectively compared to non-bioaugmented pots. Soil bioaugmentation with free cells of R. metallidurans supplied with skim milk enhanced Cr extraction by leaves by a factor of 5.2.
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https://tel.archives-ouvertes.fr/tel-00465806
Contributor : Armelle Braud <>
Submitted on : Monday, March 22, 2010 - 2:33:48 AM
Last modification on : Monday, October 19, 2020 - 10:56:20 AM
Long-term archiving on: : Monday, June 28, 2010 - 3:46:08 PM

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  • HAL Id : tel-00465806, version 1

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Armelle Braud. Procédé de phytoextraction couplé à la bioaugmentation d'un sol agricole polycontaminé par du chrome, du mercure et du plomb. Interactions entre organismes. Université de Haute Alsace - Mulhouse, 2007. Français. ⟨tel-00465806⟩

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