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UP: Umweltphysik

UP 8: Hydrosph
äre und Boden II

UP 8.3: Fachvortrag

Montag, 22. März 2004, 17:00–17:15, HS 020

Cs-137 IN SEDIMENTS OF LAGO MAGGIORE: MEASUREMENTS AND MODELING — •Victoria Putyrskaya^1,2, Eckehard Klemt¹, and Gregor Zibold¹ — ¹Fachhochschule Ravensburg-Weingarten, Doggenriedstr., D-88250 Weingarten — ²Internatioanl Sakharov Environmental University, Dolgobrodskaya str. 23, 220009 Minsk, Belarus

Sediment and water samples were taken in May and November 2003 at two different basins of Lago Maggiore. A study of the vertical Cs-137 distribution in water and sediment and of water parameters enables us to get an idea on the present radiological situation, and of the sorption and migration processes within the sediment. To get information on the association of radionuclides to the different geochemical fractions sequential extraction experiments were performed. Our model is a system of two coupled partial differential equations. It is based on sedimentation-diffusion equations and describes the input of Cs-137 into the sediment and its vertical distribution within the sediment, and it takes also into account fixation and redissolution processes as well as radioactive decay. The concentration of competing ions is used to modify the distribution coefficient Kd. Also the compaction of sediments with depth will be taken into account. To solve this system a finite element method is used. Results for different lakes will be compared to the parameters of Lago Maggiore.