Anthropogenic radionuclides in sediment in the Japan Sea; Distribution and transport processes of particulate radionuclides
Otosaka, Shigeyoshi
; Amano, Hikaru; Ito, Toshimichi
; Kawamura, Hideyuki
; Kobayashi, Takuya
; Suzuki, Takashi
; Togawa, Orihiko
; Chaykovskaya, E. L.*; Lishavskaya, T. S.*; Novichkov, V. P.*; Karasev, E. V.*; Tkalin, A. V.*; Volkov, Y. N.*
Distributions of radionuclides (
Sr,
Cs and
Pu) in seabed sediment in the Japan Sea were observed during 1998-2002. Observed inventories of anthropogenic radionuclides in sediment ranged 0.1-86 Bq m
for
Sr, 23-379 Bq m
for
Cs and 0.1-86 Bq m
for
Pu. In the deep part (
2 km depth) of the western Japan Basin,
Pu/
Cs inventory ratios were larger than those in the central Yamato Basin although inventories of radionuclides were not different between basins. The higher
Pu/
Cs ratios in the western Japan Basin were derived by the production of Pu-enriched particle in the surface layer and effective sinking of particulate materials in this region. In the marginal Yamato Basin and the Ulleung Basin, both inventories and
Pu/
Cs ratios in sediment were larger than those in the central Yamato Basin. In the eastern/southern Japan Sea, it was suggested that the supply of particulate radionuclides by the TWC enhanced accumulation of radionuclides in this region.