Hopkins Marine Station, Stanford University , 120 Ocean View Boulevard, Pacific Grove, California 93950, United States.
Environ Sci Technol. 2013 Mar 5;47(5):2287-94. doi: 10.1021/es4002423. Epub 2013 Feb 15.
The detection of Fukushima-derived radionuclides in Pacific bluefin tuna (PBFT) that crossed the Pacific Ocean to the California Current Large Marine Ecosystem (CCLME) in 2011 presented the potential to use radiocesium as a tracer in highly migratory species. This tracer requires that all western Pacific Ocean emigrants acquire the (134)Cs signal, a radioisotope undetectable in Pacific biota prior to the Fukushima accident in 2011. We tested the efficacy of the radiocesium tracer by measuring (134)Cs and (137)Cs in PBFT (n = 50) caught in the CCLME in 2012, more than a year after the Fukushima accident. All small PBFT (n = 28; recent migrants from Japan) had (134)Cs (0.7 ± 0.2 Bq kg(-1)) and elevated (137)Cs (2.0 ± 0.5 Bq kg(-1)) in their white muscle tissue. Most larger, older fish (n = 22) had no (134)Cs and only background levels of (137)Cs, showing that one year in the CCLME is sufficient for (134)Cs and (137)Cs values in PBFT to reach pre-Fukushima levels. Radiocesium concentrations in 2012 PBFT were less than half those from 2011 and well below safety guidelines for public health. Detection of (134)Cs in all recent migrant PBFT supports the use of radiocesium as a tracer in migratory animals in 2012.
2011 年，穿越太平洋抵达加利福尼亚海流大海洋生态系统（CCLME）的太平洋蓝鳍金枪鱼（PBFT）中检测到福岛衍生放射性核素，为在高度洄游物种中使用放射性铯作为示踪剂提供了可能。这种示踪剂要求所有西太平洋洄游鱼类都获得（134）Cs 信号，而该放射性同位素在 2011 年福岛事故之前是无法在太平洋生物群中检测到的。我们通过测量 2012 年在 CCLME 中捕获的 PBFT（n=50）中的（134）Cs 和（137）Cs 来测试放射性铯示踪剂的功效，这是福岛事故发生一年多以后。所有较小的 PBFT（n=28；最近从日本洄游而来的鱼类）的白肌组织中都含有（134）Cs（0.7±0.2 Bq kg-1）和（137）Cs（2.0±0.5 Bq kg-1）。大多数较大的、较老的鱼类（n=22）没有（134）Cs，只有背景水平的（137）Cs，这表明在 CCLME 中生活一年足以使 PBFT 中的（134）Cs 和（137）Cs 值达到福岛事故前的水平。2012 年 PBFT 中的放射性铯浓度不到 2011 年的一半，远低于公共卫生安全指南。所有最近洄游的 PBFT 中都检测到（134）Cs，这支持在 2012 年将放射性铯作为洄游动物的示踪剂。
