Input of [sup.129]I into the western Pacific Ocean resulting from the Fukushima nuclear event

• Published in: Journal of radioanalytical and nuclear chemistry Vol. 296; no. 2; p. 957
• Main Authors: Tumey, S.J, Guilderson, T.P, Brown, T.A, Broek, T, Buesseler, K.O
• Format: Journal Article
• Language: English
• Published: Springer 01.05.2013
• Subjects: Nuclear accidents; Tracers (Chemistry)
• ISSN: 0236-5731; 1588-2780
• DOI: 10.1007/s10967-012-2217-9

We present an initial characterization of the input of [sup.129]I into the Pacific Ocean resulting from the 2011 Fukushima nuclear accident. This characterization is based primarily on [sup.129]I measurements on samples collected from a research cruise conducted in waters off the eastern coast of Japan in June 2011. These measurements were compared with samples intended to reflect pre-Fukushima background that were collected during a May 2011 transect of the Pacific by a commercial container vessel. In surface waters, we observed peak [sup.129]I concentrations of ~300 µBq/[m.sup.3] which represents an elevation of nearly three orders of magnitude compared to pre-Fukushima back grounds. We coupled our [sup.129]I results with [sup.137]Cs measurements from the same cruise and derived an average [sup.129]I/[sup.137]Cs activity ratio of 0.442 x [10.sup.-6] for the effluent from Fukushima. Finally, we present [sup.129]I depth profiles from five stations from this cruise which form the basis for future studies of ocean transport and mixing process as well as estimations of the total budget of [sup.129]I released into the Pacific. Keywords [sup.129]Iodine * Fukushima * Environmental radioactivity * Accelerator mass spectrometry * Ocean tracers