Input of super(129)I into the western Pacific Ocean resulting from the Fukushima nuclear event

We present an initial characterization of the input of super(129)I into the Pacific Ocean resulting from the 2011 Fukushima nuclear accident. This characterization is based primarily on super(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 super(129)I concentrations of similar to 300 mu Bq/m super(3) which represents an elevation of nearly three orders of magnitude compared to pre-Fukushima backgrounds. We coupled our super(129)I results with super(137)Cs measurements from the same cruise and derived an average super(129)I/ super(137)Cs activity ratio of 0.442 x 10 super(-6) for the effluent from Fukushima. Finally, we present super(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 super(129)I released into the Pacific.