GEOC 20 |
| Andreas Birkefeld, Bernd Nowack, and Rainer Schulin. Institute of Terrestrial Ecology, Swiss Federal Institute of Technology (ETH), Grabenstrasse 3, CH-8952 Schlieren, Switzerland |
| To assess the risk potential of metal contamination in soils it is important to know the behavior of particulate contaminants which entered the soil. Examples of such particles are heavy metal containing dusts or metalliferous minerals like ores particles. The long-term dissolution behavior and phase transformations of these particles determine their environmental risk potential. We will present a new developed in-situ method to investigate the changes on particles like e.g. heavy metal minerals under environmental conditions in soils or sediments. Polymethylmethacrylate (PMMA) polymer supports were coated with selected heavy metal minerals on a thin epoxy resin film. This method provides direct contact of the particle surface with its surrounding matrix (soil, sediment) without loosing the material. The polymer supports were inserted into different soils under environmental and laboratory conditions. After different time periods they were recovered and analyzed for phase transformations and dissolution signs. Scanning electron microscopic (SEM) photographs, x-ray probe spectra and Raman spectroscopy showed clearly the occurrence of new formed mineral phases in some mineral/soil combinations. Dissolution effects of minerals are characterized by quantifying the remaining metals. First results showed that this new method is an easy tool to obtain information on the reactions of particles in soils. The method has the potential to be applied in other systems such as sediments or aquatic environments. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
8:10 AM-11:30 AM, Monday, March 29, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |