Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8082812 | Journal of Environmental Radioactivity | 2014 | 12 Pages |
Abstract
The spatial distributions of radiocesium concentration in sea sediment to a core depth of 14Â cm were investigated in the offshore region from the Fukushima Prefecture to the northern part of the Ibaraki Prefecture in February and July 2012, at a spatial resolution of 5Â min of latitude and longitude. The concentrations in the area south of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) were generally higher than those in the area north of it. In the southern area, a band of especially high concentration with a width about 20Â km was present in the region shallower than 100Â m, and a narrow minimal concentration band was found along the 200-m isobaths. In more than half of all cases, the vertical core profiles of radiocesium concentration generally showed an exponential decreasing trend with depth. However, in the area north of the FDNPP, where the radiocesium concentrations tended to be very low, radiocesium concentrations that had similar or larger magnitude compared with those of the most-surface layer were often found in deeper layers. Relatively good correlations were found between radiocesium concentrations and grain sizes of the most-surface sediment. The vertical profile of radiocesium concentration also had a relationship with grain size. In other case, the radiocesium concentration in the sediment seems to have had a dependence on the radiocesium concentration in bottom seawater, suggesting that the quantity of radiocesium supplied and the grain size were major factors determining the spatial distribution pattern of the radiocesium concentration after the FDNPP accident.
Related Topics
Physical Sciences and Engineering
Energy
Nuclear Energy and Engineering
Authors
Daisuke Ambe, Hideki Kaeriyama, Yuya Shigenobu, Ken Fujimoto, Tsuneo Ono, Hideki Sawada, Hajime Saito, Shizuho Miki, Takashi Setou, Takami Morita, Tomowo Watanabe,