Identificação mineralógica e caracterização geoquímica de metais pesados em diferentes fracções granulométricas de sedimentos aluvionares contaminados

Abstract

The occurrence of heavy metals in natural environment is mainly related to anthropic activities. One of the first steps to determine and identify contaminants in soils and sediments is the determination of textural caracteristics and sedimentary provenance of the geological materials, either anthropogenic or natural. Thus, considering the geochemical characterization carried out in an alluvial plain having high levels of potencially toxic metal, the granulometric characterization and the mineralogical identification by XRD in distinct granulometric fractions were performed with the aim of understanding the evolution of the contamination in this area. After the textural characterization and the determination of the granulometric fractions having higher concentration of contaminated minerals, these fractions were subjected of partial digestion in order to determine the contents of heavy metals present and evaluate the efectiy danger to the environment.