抄録
Japanese foods depend largely on foreign countries and domestic food supply is now no more than 30 percents if feedstuffs for livestocks are included. Therefore not only ecological/natural but also social, e.g. human activities related, transportation of fallout 90Sr are to be taken into accounts for estimation of baseline internal irradiation dose and potential health risks of Japanese peoples through dietary intake of 90Sr. Mathematical model is developed and examined for practical application on estimating Japanese dietary intake level of fallout 90Sr for past 30 years.
The main results obtained in this study under the limited assumptions are as follows:
(1) The proposed model is promising for evaluating the Japanese baseline dietary intake of global radioactive fallout 90Sr.
(2) Japanese dietary intake of 90Sr depends mainly on vegetable foods. Almost 60% of Japanese dietary 90Sr intake is now fed from foreign countries through foods import.
(3) Direct deposition coefficient of 90Sr on agricultural plants is highly sensitive to the dietary intake for high deposition periods of fallout 90Sr, and environmental decay coefficient is for low deposition periods. Transfer factor of 90Sr through root uptake is sensitive for both periods.