Recent Transport History of Fukushima Radioactivity in the Northeast Pacific Ocean.

The large inventory of radioactivity released during the March, 2011 Fukushima Dai-ichi nuclear reactor accident in Japan spread rapidly across the North Pacific Ocean and was first observed at the westernmost station on Line P, an oceanographic sampling line extending 1500 km westward of British Columbia (BC), Canada in June 2012. Here, time series measurements of Cs and Cs in seawater on Line P and on the CLIVAR-P16N 152°W line reveal the recent transport history of the Fukushima radioactivity tracer plume through the northeast Pacific Ocean. During 2013 and 2014 the Fukushima plume spread onto the Canadian continental shelf and by 2015 and early 2016 it reached Cs values of 6-8 Bq/m in surface water along Line P.

Fukushima Daiichi-Derived Radionuclides in the Ocean: Transport, Fate, and Impacts.

The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea.

Arrival of the Fukushima radioactivity plume in North American continental waters.

The large discharge of radioactivity into the northwest Pacific Ocean from the 2011 Fukushima Dai-ichi nuclear reactor accident has generated considerable concern about the spread of this material across the ocean to North America. We report here the first systematic study to our knowledge of the transport of the Fukushima marine radioactivity signal to the eastern North Pacific. Time series measurements of (134)Cs and (137)Cs in seawater revealed the initial arrival of the Fukushima signal by ocean current transport at a location 1,500 km west of British Columbia, Canada, in June 2012, about 1.

Radioactivity near the sunken submarine "Kursk" in the Southern Barents Sea.

Radioactivity measurements were conducted on seawater, sediment, and biota samples collected in the vicinity of the Russian submarine "Kursk" in September, 2000, within 1 month of the vessel's sinking in the Barents Sea to determine whether leakage of radioactivity from the vessel's two nuclear reactors had occurred and to assess the impact on one of the most productive fishing areas in the world. Levels of radioactivity in surface sediments and biota are within the range of values previously measured in the Barents Sea and can be ascribed to inputs from global fallout, European nuclear fuel reprocessing facilities, and the Chernobyl accident. However, levels of 1291 in seawater in the Southern Barents Sea increased by 500% between 1992 and 2000, and the 129I/137Cs ratio increased by more than an order of magnitude during this time, owing to long-range transport of releases from reprocessing facilities at Sellafield (U.