Distribution of Cs-137 and Pu-239,Pu-240 in the surface waters of the East Sea (Sea of Japan)

Abstract

Surface and subsurface water samples for Cs-137 and Pu-239,Pu-240 analysis were collected in the East Sea (Sea of Japan) during August 1993, The Cs-137 levels of the surface waters are quite homogeneous in the East Sea (average = 3.1+/-0.2 mBq kg(-1)). The Pu-239,Pu-240 levels vary from 6 to 10 mu Bq kg(-1) in the surface, Pu-239,Pu-240 to Cs-137 ratios in the surface water are within 0.002 to 0.003. The East Sea may be regarded as a part of the North Pacific Ocean in terms of Cs-137 dispersal in the surface, where the Cs-137 contents of the surface seawater seem to be controlled primarily by the atmospheric input. However, since our sampling was made just two months prior to the widely publicized Russian dumping incident on the 17th October 1993, our measurements may provide background data to assess the immediate impact of the Russian dumping on the levels of Cs-137 and Pu-239,Pu-240 in the East Sea. (C) 1997 Elsevier Science Ltd. All rights reserved.