Extracciones quimicas secuenciales de metales pesados. Aplicacion en ciencias geologicas

摘要: Sequential chemical extraction methodologies are applied in Geological Sciences with the objective of determining solid speciation for trace metals present soil, sediment and rock samples. Such information is not available from a conventional chemica1 analysis. At time wide variety sequential protocols exists, but none them has been imposed as an international standard method yet. The fractions material that these usually allow to distinguish following: Exchangeable, carbonate, Fe-Mn oxide-hydroxide, organic, residual. Different methods differ used reagents well experimental conditions, depending on particular objectives. different fields geological sciences, mainly environmental geochemistry aquatic systems (rivers, lakes, estuaries), edaphology also groundwater hydrology. In general, involve important methodological problems which have pointed out severa1 authors. Among Reagent selectivity, operative definition methods, elemental redistribution (or readsorption), variable scarcity reference certificated materials, strong difficulty order validate existing evaluation its precision. spite al1 mentioned, at constitute better approach describe geochemical association elements materials.