Entwicklung eines Analysenverfahrens für Rutheniumspuren in Pflanzenmaterial und Ermittlung der Transferfaktoren Boden/Pflanzen für Rutheniumverbindungen aus Wiederaufarbeitungsanlagen

Summary

Considerably different transfer factors soil/plant are reported in literature for the fission product ruthenium. As ruthenium belongs to those radioactive nuclides, that could be released from a reprocessing plant during an accident, reliable transfer factors should be explored under middle-European conditions for some typical nutrition plants. In an artificial humous and sandy soil spiked with ^106Ru as RuO₂ and RuCl₃, pasture grass was grown under artificial illumination in our laboratory. The amounts of ruthenium taken up by the plants were determined by γ-spectrometry. For open-air investigations with pasture grass, wheat and potatoes inactive ruthenium(III) chloride and ruthenium nitrosylchloride were used. Ruthenium was determined by electrothermal atomic absorption spectrometry (ETAAS) after destroying the organic material and concentrating the solution. The concentration and chemical form of the ruthenium exert an unimportant influence on the transfer factor. For the pasture-grass, the stems of wheat and the weed of potatoes it amounts to 0.00005 to 0.0015, for the ear of wheat to about 0.00005. In peeled potatoes there was no ruthenium detectable, therefore the limit of detection leads to a transfer factor ≤0.00001. So it is evident that ruthenium is little available for the roots of the plants. In the event of an accident in a nuclear plant the uptake of radioactive ruthenium by roots has only negligible radioecological consequences. This applies even if 50 years of ruthenium enrichment in the soil are assumed.