Speaker
Description
The present work investigates Tc uptake from several standardized soils (RefeSol) into wheat, potatoes, carrots and peas. Experiments were performed in batches, columns and lysimeter experiments. Transfer factors and plant availability were obtained by sequential extraction. In order to understanding the plant uptake on a cellular level, the radionuclide distribution was imaged by mass spectrometry within the cellular structures of plants at varying concentrations. In a first step, plants of Daucus carota and Pisum sativum labelled with iodine and rhenium were examined, at concentrations in the range of 10 mM. Cross sections of several plant parts were imaged by secondary ion mass spectrometry (SIMS) after cryogenation in order to preserve cell structure. In a second step, the distribution of T-99c in the two plant species was determined. For radiological reasons, a concentration three orders of magnitude lower was used, rendering measurements with SIMS impossible. Therefore, resonant laser secondary neutral mass spectrometry (rL-SNMS) was used to image Tc-99 with suppression of molecular isobaric interferences. The measurement of only about 1E10 atoms of Tc-99 is demonstrated and the distribution of Tc-99 within a single epidermal cell is imaged.