1991 Volume 40 Issue 11 Pages 440-443
In order to assess the behavior of radioiodine in rice fields, we have performed laboratory experiments, using 125I tracer, on the desorption phenomena of iodine from soil during rice cultivation. Most of the 125I added to the soil was adsorbed by the soil solid phase at the beginning of the experiment. However, the iodine started to desorb into the soil solution with the growth of rice plants. The highest desorption rate of iodine was found around the flowering period, i.e, nearly 30% of the 125I was desorbed from Ando soil into the soil solution. In contrast to this, no particular increase in the iodine desorption was observed from the uncultivated flooded soil. It was suggested that rice plants had some influence upon iodine desorption from soil and the desorption also depended on the soil types.