Use of Si-Phytoliths in depollution of mining areas in the Cerrado-Caatinga region, MG, Brazil
Résumé
Treating of metal contaminated areas became a very important problem with increasing industrial and agricultural activities. Many of the used methods are very expensive, need intensive human interaction or have a very negative influence on the cleaned regions. The use of Si-Phytolites is a simple, low cost and a very effective way to obtain good results in low contaminated or as the final process in highly contaminated places. The method is based on the fact that a lot of plants produce Si-Phytolits and trap significant quantities of heavy metals in these amorphous to microcrystalline structures. The solubility of the Si-Phytolits under Brazilian soil conditions is lower than that of the heavy elements brought directly in the soil by the wash or fall out, or by degrading of organic parts of the plants at the upper part of surface. In this way, it is possible to retain liberation to the environment from short to longer periods and attend environmental laws and norms.
Initial tests with different plants like Ricinus comunis L., Andropogon arundinaceus Willd., Zea Mays L., Brachiaria sp. L. and Saccharum officinarum L. planted on substrates with metal concentrations (Al, Fe, Mn, Ti, Zn, Cu, Pb, Cd, Ba, Hg, S) have shown that the plants absorbed elements and quantities in the different parts like leaves, roots, stems, flowers and fruits. This allows a selective use due to contamination varieties and a possible economic use of parts of the plants and an effective planning of the decontamination conditions.
Origine : Fichiers produits par l'(les) auteur(s)
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