Wada Seiichi, Ito Nobuhiko, Watanabe Masamichi, Kakizaki Takehiko, Natsuhori Masahiro, Kawamata Jun, Urayama Yoshio
Laboratory of Veterinary Radiology and Radiation Biology, School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
Fukushima Headquarters for Animal Rescue, Fukushima, Fukushima, Japan.
PLoS One. 2017 Jan 18;12(1):e0169365. doi: 10.1371/journal.pone.0169365. eCollection 2017.
As a result of the 2011 nuclear incident that occurred at the Fukushima Nuclear Power Plant, a large number of abandoned dogs and cats were left within the disaster zone. A small number of these animals were rescued and cared for at shelters. Prior to the dispersal of these animals to their owners or fosterers, we evaluated the degree of internal radiocesium contamination using a specially designed whole-body counter. We conducted 863 non-invasive measurements of gamma rays due to internal radioactive cesium for 68 dogs and 120 cats at one shelter. After plotting graphs of 137Cs density we generated exponential functions of decay from seven dogs and six cats. From the regression formulae, we were able to determine the biological half-lives as 38.2 days for dogs and 30.8 days for cats. We found that in dogs there was a correlation between the biological half-life of radioactive cesium and age. Using our data, we estimated whole-body densities for each cat and dog at the time when they were rescued. We found that there were deviations in the data distributions among the different species, likely due to the timing of rescue, or living habits prior to rescue. A significant correlation was found when extracted feline reproductive organs were analyzed; the coefficients for the estimation of whole-body densities were approximately 7-fold higher than those based on the extracted feline reproductive organs. This may be due to the fact that majority of the radioactive cesium accumulates within muscular tissue with less distribution in other organs. It is possible to plan the appropriate management period in an animal shelter based on the use of the biological half-life of radioactive cesium calculated in this study. We believe that the correlations we uncovered in this work would be of great use for the management of companion animals in the event of a future nuclear accident.
由于2011年福岛核电站发生的核事故，灾区留下了大量被遗弃的狗和猫。其中少数动物被救起并在收容所得到照料。在将这些动物分散给它们的主人或寄养人之前，我们使用专门设计的全身计数器评估了它们体内放射性铯的污染程度。我们在一个收容所对68只狗和120只猫进行了863次因体内放射性铯产生的伽马射线非侵入性测量。绘制137Cs密度图后，我们从7只狗和6只猫中生成了衰变指数函数。根据回归公式，我们能够确定狗的生物半衰期为38.2天，猫的为30.8天。我们发现狗体内放射性铯的生物半衰期与年龄之间存在相关性。利用我们的数据，我们估计了每只猫和狗被救时的全身密度。我们发现不同物种的数据分布存在偏差，这可能是由于救援时间或救援前的生活习惯所致。在对提取的猫生殖器官进行分析时发现了显著相关性；全身密度估计系数比基于提取的猫生殖器官的系数高出约7倍。这可能是因为大部分放射性铯积聚在肌肉组织中，在其他器官中的分布较少。根据本研究计算出的放射性铯生物半衰期，可以规划动物收容所的适当管理期。我们相信，我们在这项工作中发现的相关性将对未来核事故中伴侣动物的管理有很大帮助。
