XANES (X-Ray Absortion Near Edge) como herramienta para evaluación de riesgos medioambientales: aplicación al caso de Hg
- José María Esbrí Víctor 1
- Eva M. García Noguero 1
- Beatriz Guerrero López 2
- David Kocman 3
- Anna Bernaus Darbra 2
- Xavier Gaona Martínez 2
- Pablo León Higueras Higueras 1
- Milena Horvat 3
- Manuel Valiente Malmagro 2
- 1 Dept. Ingeniería Geológica y Minera, Escuela Universitaria Politécnica de Almadén
- 2 Dept. Química, Universitat Autònoma de Barcelona
- 3 Jozef Stefan Institute, SI-1001 Ljubljana, Eslovenia
ISSN: 1576-5172
Ano de publicación: 2008
Título do exemplar: VII Congreso Geológico de España
Número: 10
Páxinas: 1097-1100
Tipo: Artigo
Outras publicacións en: Geotemas (Madrid)
Resumo
The mobility and bioavailability of the heavy metals in the environment depends not only on its intrinsic toxicity, but also on the chemical species in which they are found. For this reason, the chemical speciation becomes an important risk assessment tool in both, public health and environment. In this work, different mercury compounds are featured in samples from three mining districts, which have been important through history: Almadén (Central Spain), Asturias (N Spain) and Idrija (Slovenia). Nowadays, there are few techniques which allow us to determinate the speciation of heavy metals, and even less in the case of solid and disordered samples. In this sense, XAS (X-ray Absorption Spectrometry) techniques give us remarkable advantages. Theses techniques are based in the analysis of interactions between the sample and a high energy X-Ray beam generated in a synchrotron facility. In this way, we obtain information about the oxidation state and the coordination index in which the target element is present. In the specific case of XANES (X-Ray Absorption Near-Edge Spectrometry) the information comes from the comparison of the samples spectra and the pure compounds spectra. Our results indicate that, for the three districts studied, there is a predominance of low solubility phases on mine dumps and calcines, meanwhile on soils and stream sediments the predominance corresponds to soluble phases.