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Descripción
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| Phytoextraction is a cost-effective and environmental-friendly technology that uses metal hyperaccumulator plants to remove heavy metals from soils, transporting and concentrating them from the soil into the above-ground shoots, which can be harvested. These plants enhance metal uptake by releasing through root exudates chelating agents, such as Low Molecular Weight Organic Acids (LMWOA) which increase metal availability. The objective of this study is to investigate the release of Zn and Cu from two naturally contaminated soils by column leaching in response to the presence of different types and concentrations of organic acids. These soils were collected from the villages Garganta de los Montes and El Cuadrón, in the north of Madrid, where there was an intense mining activity more than 50 years ago. Soil samples were air-dried and passed through a 2mm sieve. They were analyzed for pH, Electric Conductivity (EC), Cation Exchange Capacity (CEC), Oxidizable Organic Carbon, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC) and texture. Also a sequential extraction was used to fractionate Zn, Cu and Cd, following the procedure of Tessier et al. (1979). The column leaching experiment consisted of 36 glass columns with 300 g of soil in each one. Six treatments were applied to both soils (in triplicate) adding, every two days, 50 mL of a solution containing a background electrolyte with different treatments: without organic acid, 0.5 mM citric acid, 10 mM citric acid, 0.5 mM tartaric acid, 10 mM tartaric acid, and 5 mM citric + 5 mM tartaric. In the column lixiviates we measured pH and metal content (Zn and Cu) by Atomic Absorption Spectrometry (AAS). Zinc concentration in lixiviates was much larger in all treatments with El Cuadrón soil than with Garganta soil, due to a low pH and a higher initial adsorbed Zn content. The same tendency was found for Cu when we added low concentration of organic acids, but when using increasing concentrations of these, Cu desorption was higher in Garganta soil. Results indicate that adding increasing concentration of organic acids in both soils lead to a significant increase of Cu desorption, particularly with citrate. The desorption behavior of Zn with different treatments in each soil was not so evident | |
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Internacional
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Si |
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Nombre congreso
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3rd IMEBE (International Meeting on Environmental Biotechnology) |
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Tipo de participación
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960 |
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Lugar del congreso
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Palma de Mallorca, España |
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Revisores
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Si |
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ISBN o ISSN
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99-9999-999-9 |
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DOI
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Fecha inicio congreso
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21/09/2008 |
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Fecha fin congreso
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25/10/2008 |
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0 |
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Hasta la página
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0 |
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Título de las actas
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Libro de resúmenes |