Foliar uptake of cesium, iodine and strontium and their transfer to the edible parts of beans, potatoes and radishes

Abstract

Considerable fractions of radionuclide solutions deposited on the surface of the leaves may be transferred to the edible parts of plants. In radishes we observed a transfer of more than 40% of the applied cesium radioisotope within a few days. A rather similar uptake was found for beans and potatoes when harvested a month after application of radioactivity. As much as 60% of the applied cesium-isotope remained in (or on) the potato leaves even 8 days after application. The major part could however be washed off the leaves a few hours after application. When radishes were showered with water within 7 h after the application of activity the uptake was greatly reduced. No competitive effect of potassium chloride for the foliar uptake of cesium was found. A 10 -2 M colloidal suspension of Prussian Blue, a chelating agent for monovalent alkali metals such as potassium, cesium, or other monovalent cations, applied as droplets to the leaves one day prior to application of active cesium was found to strongly inhibit the transfer of cesium to the radish. The transfer of iodine and strontium to the edible parts was found to be negligible (or slower) as compared to cesium. In most cases no detectable amounts of these two nuclides were transfered to the edible parts of the radish after 2–5 weeks.