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  • 1 Korea Institute of Nuclear Safety Department of Radiation and Engineering Research Department of Radiological Safety Research P.O. Box 114 Yusong, Taejon 305-338 Korea
  • | 2 Korea Institute of Nuclear Safety Department of Radiological Safety Research P.O. Box 114 Yusong, Taejon 305-338 Korea
  • | 3 Korea Ocean Research and Development Institute, Ansan Isotope Oceanography Laboratory P.O.Box 29 Seoul 425-600 Korea
  • | 4 Meteorological Research Institute Geochemical Research Department Tsukuba, Ibaraki 305-0052 Japan
  • | 5 University of Linköping Department of Radiation Physics S-581 85 Linköping Sweden
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Abstract  

239+240Pu concentrations and 240Pu/239Pu atom ratios in bottom sediments of the Yellow Sea, Korea Strait, East Sea (Sea of Japan), Sea of Okhotsk, and Northwest Pacific Ocean were determined. In coastal sediments near the Korean Peninsula, 239+240Pu concentrations varied from 0.02 to 1.72 Bq.kg-1, and their 240Pu/239Pu atom ratios from 0.15 to 0.24, with an average of 0.20±0.03. 240Pu/239Pu atom ratios of bottom sediments in the deep NW Pacific Ocean and its marginal seas (East, Okhotsk seas) were in the range of 0.15-0.23. A little elevated 240Pu/239Pu atom ratios in the bottom layer sediment may be due to Pu released into the environment during the pre-moratorium period, having high 240Pu/239Pu atom ratios and low 238Pu/239+240Pu activity ratios.