The amounts of cesium-134 and -137 were measured in vegetables which were contaminated by the fall-out due to the Chernobyl reactor accident. In the case where the plants were sown or planted before this incident occurred they were contaminated almost entirely by deposition of the radionuclides on their exposed parts (stalks and foliage), plants which were sown or planted after 1st May, contamination occurred mainly by transfer from soil to plant via the roots.The activities found were in most cases too small to be either measured accurately or for real differences to be found in various parts of the plants. Some of the values were within the fluctuations of the background. A normal consumption of vegetables grown in Northern Switzerland could therefore not lead to a significant increase of ingested radioactivity. Some nuts, cereals and berries on the other hand contained considerably higher activities. This was surprising since the migration of cesium in soil is too slow to have reached the root areas. We assumed that the cesium must have been incorporated into the fruit via the leaves. To prove this, we applied aqueous solutions of the radionuclides cesium, strontium and iodine to the leaves of some vegetable plants and measured the resulting activity in the edible parts. In some cases we found a transfer of more than 40% of the total cesium applied to the leaf in the edible part of the plant.Further experiments, such as washing the leaves at certain intervals after the application, competition with other non-radioactive elements, influence of the experimental conditions as well as the structure of the leaf are under investigation.
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- Transfer of Radionuclides to Food Plants: Root Versus Foliar Uptake
- Springer Netherlands