Central Laboratory, Marine Ecology Research Institute, 300 Iwawada, Onjuku-machi, Isumi-gun, Chiba 299-5105, Japan.
Marine Ecology Research Institute, Tohwa-Edogawbashi Bldg., 347 Yamabuki-cho, Shinjuku-ku, Tokyo 162-0801, Japan.
Sci Rep. 2017 Jan 4;7:39874. doi: 10.1038/srep39874.
After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (Cs, Cs, and Cs) were measured in zooplankton collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic Cs concentration peaks in zooplankton. In addition, the atom ratio of Cs/Cs in zooplankton was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of Cs in zooplankton via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within zooplankton samples, which could be the main factor underlying the sporadic appearance of high Cs concentrations in zooplankton as well as the higher ratio of Cs/Cs in zooplankton than in seawater.
2011 年 3 月福岛第一核电站事故后，我们于 2012 年 5 月至 2015 年 2 月期间在日本东海岸太平洋采集了浮游动物，并对其中的铯同位素（Cs、Cs 和 Cs）浓度进行了测量。这些数据的时间序列显示，浮游动物中的 Cs 浓度呈零星峰值。此外，在整个采样期间，浮游动物体内的 Cs/Cs 原子比与周围海水中的 Cs/Cs 原子比相比一直偏高。这些现象不能完全用通过摄入周围海水、浮游动物样本中再悬浮沉积物或浮游动物的分类组成来解释。放射自显影显示浮游动物样本内存在高放射性粒子，这可能是导致浮游动物体内 Cs 浓度呈零星峰值以及 Cs/Cs 原子比高于海水的主要因素。
