抄録
Tellurium (Te) isotopes were released into the environment with other radioactive isotopes including cesium (Cs) and iodine (I) as a result of the accident at the Fukushima Daiichi Nuclear Power Plant. There is a possibility that the ingestion of Te-127m and Te-129m with foods may cause a significant internal radiation dose for the public because the half-lives of these isotopes are relatively long 109 and 33.6 days, respectively. Data on the transfer of Te from cultivated soil to plants through roots is essential to estimate the contribution of radioactive Te to the internal radiation dose in the public. However, little is known about transfer of Te from soil to plants in the ecosystem. Therefore, we previously estimated transfer factors for stable Te and Cs from soil to radish and komatsuna by experiments. In the present study, we calculated ratios of committed effective dose for radioactive Te to radioactive Cs by using our experimentally estimated transfer factors for stable Te and Cs as well as those reported by the IAEA. Ratios calculated with transfer factors estimated by the IAEA report were two orders of magnitude higher than those calculated with our measured transfer factors. These results suggest that the committed effective dose from ingestion of radioactive Te is probably considerably lower than the dose based on IAEA results.
