KuvausThe main aim in the Ph.D. project is to study radon sources in different types of sediments and soils. The research program is based on a series of case studies at undisturbed natural sites including area with average U-content, as well as U mineralization.
The most important sites for the study are: Palmottu (undisturbed U-mineralization, ca. 80 km NW to Helsinki, Finland), Askola (former U-mining and U-enrichment site, ca. 80 km NE to Helsinki, Finland) and Olkiluoto (average U-bearing sediment showing clear red-ox profile, ca. 270 km NW to Helsinki, Finland). Sampling will be focussed on overburden (like till and soil samples).
During the research presence and distribution of easily removable such as, adsorbed, ionic bound etc. and in crystal lattice persistently bound uranium and radium were analyzed in collected soil horizons and sediments. To separate these soil constituents, selective leaching technique were used. Following the extraction, multiple elemental ICP-MS and liquid scintillation counter (LSC) analyses were carried out on the leachetes. By the multiple elemental analyses we gained content of U, Th, and other elements, such as Fe, Mn, Ca and Ba which have pointed on the efficiency of the extraction. The Ra-content of the leachates has been analyzed by liquid scintillation counter. The activity concentration ratios of radium and uranium in different type of soils and sediments indicate the behaviour of these elements during weathering and soil formation processes. To better understanding of weathering effects on U-bearing minerals as a major source of persistently bound uranium, we analyzed the chemical composition and textural relations of weathered and unaltered part of minerals using SEM-EDAX and EPMA techniques.
Title of thesis: Geochemical and mineralogical investigation of overburden profiles in glaciated terrain, Finland – implication for the assessment of radon emission –
|Aikajakso||1 lokakuuta 2007 → 31 lokakuuta 2008|
|Tutkimuksen ajankohta||Eötvös University|