Institut de Radioprotection et de Sûreté Nucléaire, (IRSN), BP 3, 13115, Cadarache, Saint Paul Lez Durance, France.
Environ Sci Technol. 2011 Sep 15;45(18):7670-7. doi: 10.1021/es2017158. Epub 2011 Aug 23.
Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 ((131)I) and cesium isotopes ((137)Cs and (134)Cs) were transported across the Pacific toward the North American continent and reached Europe despite dispersion and washout along the route of the contaminated air masses. In Europe, the first signs of the releases were detected 7 days later while the first peak of activity level was observed between March 28th and March 30th. Time variations over a 20-day period and spatial variations across more than 150 sampling locations in Europe made it possible to characterize the contaminated air masses. After the Chernobyl accident, only a few measurements of the gaseous (131)I fraction were conducted compared to the number of measurements for the particulate fraction. Several studies had already pointed out the importance of the gaseous (131)I and the large underestimation of the total (131)I airborne activity level, and subsequent calculations of inhalation dose, if neglected. The measurements made across Europe following the releases from the Fukushima NPP reactors have provided a significant amount of new data on the ratio of the gaseous (131)I fraction to total (131)I, both on a spatial scale and its temporal variation. It can be pointed out that during the Fukushima event, the (134)Cs to (137)Cs ratio proved to be different from that observed after the Chernobyl accident. The data set provided in this paper is the most comprehensive survey of the main relevant airborne radionuclides from the Fukushima reactors, measured across Europe. A rough estimate of the total (131)I inventory that has passed over Europe during this period was <1% of the released amount. According to the measurements, airborne activity levels remain of no concern for public health in Europe.
2011 年 3 月 12 日，福岛第一核电站（Fukushima Dai-ichi NPP）受损反应堆开始向大气中释放放射性物质。在释放的各种放射性核素中，碘-131（(131)I）和铯同位素（(137)Cs 和 (134)Cs）经太平洋向北美大陆迁移，并在沿途的受污染空气团的扩散和冲刷作用下抵达欧洲。在欧洲，7 天后首次检测到释放物的迹象，而在 3 月 28 日至 30 日期间观察到了活性水平的第一个峰值。在欧洲，20 天时间内的时间变化和超过 150 个采样点的空间变化使受污染空气团的特征化成为可能。在切尔诺贝利事故之后，与对颗粒物部分的测量数量相比，只有少数几次对气态（131）I 部分进行了测量。几项研究已经指出了气态（131）I 的重要性，以及如果忽视其存在，对总（131）I 空中活性水平以及随后的吸入剂量的严重低估。在福岛核电站反应堆释放后，在整个欧洲进行的测量提供了大量关于气态（131）I 部分与总（131）I 的比值的新数据，无论是在空间尺度还是其时间变化方面。可以指出的是，在福岛事件中，（134）Cs 与（137）Cs 的比值与切尔诺贝利事故后观察到的比值不同。本文提供的数据是对跨越欧洲的福岛反应堆主要相关空气传播放射性核素的最全面调查。在此期间通过欧洲上空的总（131）I 库存的粗略估计约为释放量的 1%。根据测量结果，空气中的放射性活度水平对欧洲公众健康没有影响。
