RADIOISOTOPES

Brown rice of non-glutinous paddy rice (Oriza sativa) was used to investigate radiocaesium translocation to grains by selecting hulled rice and unsuitable rice grains for food. It was assumed that hulled rice was not mature enough to remove hulls compared to mature rice so that hulled rice was classified as immature rice. The unsuitable rice grains were such as colored or not proper shape ones, thus it was though that they were disturbed their filling process and thus their nutritional condition was not in the same level as the normally grown mature grains. The weight of immature rice grains had about 95％ of normal-weight grains and thus it was indeed slightly immature but the ¹³⁷Cs concentration was almost the same as that of the normal mature grains. On the other hand, unsuitable grains were low in ¹³⁷Cs concentration by 14％, suggesting that translocation of radiocesium was affected from early stage of filling process. Probably the decrease would occur especially if germs and/or aleurone layer were damaged.