부산대학교 도서관

South of Belarus is highly radiocontaminated even in 20 years after the Chernobyl catastrophe in 1986, and consequent environmental changes are stored in the soil, plants and animals. The major radionuclides in the contaminated areas are 137Cs and 90Sr, and their physical half lives are 30.2 and 28.9 years, respectively. It is expected that the radionuclides are concentrated by the food chain into the organisms which are living in the contaminated area, and radionuclides remain in the irradiated organisms not only externally but also internally for long periods. The evidences of radiation effects on the organisms living in the contaminated area have been reported by many scientists. But most reports have not shown the exact radioactivity and period of exposure. The exact radioactivity in organisms should have been known to assess the long term low dose rate and low dose internal and external radiation effect. We measured the 137Cs radioactivity and its distribution in the plants (trees, berries) and animals (insects, frogs, moles, mice) in the highly contaminated area (Masani) and the low contaminated area (Babchin). The 137Cs radioactivities of mice in 2005 were compared with those in 1997. The remaining amounts of 137Cs in organs was about 2% of those in 1997. Additionally, we tried to detect quantitatively the contaminated radionuclides-induced DNA double-strand breaks by γ-H2AX foci in the organs of mice living in highly contaminated area (Supported by MEXT, JSPS and Heiwa-Nakajima Foundation).