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

白俄罗斯南部在1986年切尔诺贝利灾难发生后的19年里仍然受到高度放射性污染，由此产生的环境变化储存在土壤、植物和动物中。污染区的主要放射性核素是^<137>Cs和^<90>Sr，其物理半衰期分别为30.2年和28.9年。土壤缓慢的自清洁效率（估计半衰期为24年）导致了封闭环境中的长期放射性污染。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内，放射性核素不仅在外部而且在内部长期留在受辐照的生物体内。许多科学家报告了辐射对生活在受污染地区的生物体产生影响的证据。小鼠和青蛙的染色体畸变率比灾难前增加了两倍。但大多数报告没有显示确切的放射性和暴露时间。为了评估长期低剂量率和低剂量内、外辐射效应，必须知道生物体内的准确放射性，我们测量了<137>高污染区（白俄罗斯戈梅利州Masani村）和低污染区（白俄罗斯戈梅利州Babchin村）的^ Cs放射性及其在植物（树木、浆果）和动物（昆虫、青蛙、鼹鼠、小鼠）体内的分布。对<137>2005年和1997年小鼠的γ Cs活性进行了比较。2005<137>年时，^ Cs在器官中的残留率约为2%。估算其生态半衰期为1.511年。此外，我们尝试了定量检测污染放射性核素引起的DNA双链断裂的γ-H2 AX灶在小鼠器官中生活在污染区。但在高污染区的动物细胞中未检测到γ-H2 AX灶的信号。

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.