Genetic effects and biological concentration of radionuclides in plants and animals after Chernobyl catastrophe.

即使在1986年切尔诺贝利灾难后的19年里，白俄罗斯南部仍受到高度放射性污染，随之而来的环境变化储存在土壤、植物和动物中。污染区放射性核素主要为~(137)Cs和~(90)Sr，物理半衰期分别为30.2年和28.9年。土壤的缓慢自洁效率(估计半衰期为24年)导致了封闭环境中长期的放射性污染。预计放射性核素会通过食物链集中到生活在受污染地区的生物体中，放射性核素不仅在外部而且在内部长期留在受辐射的生物体中。许多科学家报道了生活在受污染地区的有机体受到辐射影响的证据。小鼠和青蛙的染色体畸变率比灾难前增加了一倍。但大多数报告都没有显示确切的放射性和暴露时间。我们测量了高污染地区(白俄罗斯戈梅尔地区马萨尼村)和低污染地区(白俄罗斯戈梅尔地区巴钦村)植物(树木、浆果)和动物(昆虫、青蛙、鼹鼠、老鼠)中~(137)Cs的放射性及其分布。比较了2005年和1997年小鼠体内~(137)Cs和~(137)Cs的活性。2005年~(137)Cs在器官中的残留率约为2%。估计其生态半衰期为1.511年。此外，我们还尝试了用γ-H_2AX焦点定量检测受污染的放射性核素引起的小鼠器官中DNA双链断裂。但在高污染地区的动物细胞中也没有检测到γ-H_2AX焦点的信号。

South of Belarus is highly radiocontaminated even in 19 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 ^<137>Cs and ^<90>Sr, and their physical half lives are 30.2 and 28.9 years, respectively. Slow self-cleaning efficiency of the soil (estimated half life is 24 years) resulted in the long term radiocontamination in the closed environment. 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 evidence of radiation effects for the organisms living in the contaminated area were reported by many scientists. Chromosome aberration rate in mice and frogs were increased twice higher than before catastrophe. But most of reports were 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 ^<137>Cs radioactivity and its distribution in the plants (trees, berries) and animals (insects, frogs, moles, mice) in the highly contaminated area (Masani village, Gomel region, Belarus) and the low contaminated area (Babchin village, Gomel region, Belarus). The ^<137>Cs activity of mouse in 2005 was compared with mouse of 1997. The remaining rate of ^<137>Cs in organs at 2005 was about 2%. And it was estimated that the ecological half life was 1.511 years. Additionally, we tried the quantitative detection of contaminated radionuclides-induced DNA double-strand breaks by gamma-H2AX foci in mouse organs living in contaminated area. But the signal of gamma-H2AX foci was not detected even in animal cells in highly contaminated area.