Transfer of Radionuclides to Crop Plants through Roots

—Radioiodine—

Abstract

In an atmospheric discharge of radioiodines, direct deposition of the nuclides onto leaf surface must be the most significant pathway. However, root uptake is also of importance specifically for ¹²⁹I because of its long half life of 1.57×10⁷ years.
In order to estimate the amount of the nuclide transferred to the crop plants from contaminated field, the experiments were carried out using solution culture. Rice plant, Oryza sativa cv, koshihikari, spinach, Spinacea oleracea L., radish, Raphanus sativus L., and the other four kinds of crop plants were exposed to culture solution in which Na¹³¹I were contained. The transfer rates, defined as the ratio of activity of plant sample per day to the mean activity of culture solution, were calculated. And the differences by the organs of each crop plant and by plant species were discussed in this paper. Temporal critical crop plants for 129I were selected.