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Hain, K.*; Martschini, M.*; G
lce, F.*; Honda, Maki; Lachner, J.*; Kern, M.*; Pitters, J.*; Quinto, F.*; Sakaguchi, Aya*; Steier, P.*; et al.
Frontiers in Marine Science (Internet), 9, p.837515_1 - 837515_17, 2022/03
Times Cited Count：12 Percentile：95.34(Environmental Sciences)Recent major advances in accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and isobar suppression have opened possibilities for the analysis of additional long-lived radionuclides at ultra-low environmental concentrations. These radionuclides, including 
U, 
Cs, 
Tc and 
Sr, will become important for oceanographic tracer application due to their generally conservative behavior in ocean water. In particular, the isotope ratios U/
U and 
Cs/Cs have proven to be powerful fingerprints for emission source identification as they are not affected by elemental fractionation. Improved detection efficiencies allowed us to analyze all major long-lived actinides, i.e. U, 
Np, 
Pu, 
Am as well as the very rare U, in the same 10 L water samples of an exemplary depth profile from the northwest Pacific Ocean. Especially for Sr analysis, our new approach has already been validated for selected reference materials (e.g. IAEA-A-12) and is ready for application in oceanographic studies. We estimate that a sample volume of only (1-3) L ocean water is sufficient for Sr as well as Cs analysis, respectively.
Povinec, P. P.*; Aramaki, Takafumi*; Burr, G. S.*; Jull, A. J. T.*; Liong Wee Kwong, L.*; Togawa, Orihiko
Radiocarbon, 46(2), p.583 - 594, 2004/09
Times Cited Count：16 Percentile：32.44(Geochemistry & Geophysics)no abstracts in English
Seko, Noriaki; Katakai, Akio; Hasegawa, Shin; Tamada, Masao; Kasai, Noboru; Takeda, Hayato*; Sugo, Takanobu; Saito, Kyoichi*
Nuclear Technology, 144(2), p.274 - 278, 2003/11
Times Cited Count：129 Percentile：98.72(Nuclear Science & Technology)The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg-U/m
in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific non-woven fabric was used as the adsorbent packed in an adsorption cage. We submerged adsorption cages, 16 m
in cross-sectional area and 16 cm in height, in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The cage consisted of stacks of 52,000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the non-woven fabric was more than one kg in terms of yellow cake during a total submersion time of 240 days in the ocean.
Povinec, P. P.*; Livingston, H. D.*; Shima, Shigeki*; Aoyama, Michio*; Gastaud, J.*; Goroncy, I.*; Hirose, Katsumi*; Huynh-Ngoc, L.*; Ikeuchi, Yoshihiro*; Ito, Toshimichi; et al.
Deep Sea Research Part 2: Topical Studies in Oceanography, 50(17-21), p.2607 - 2637, 2003/09
Times Cited Count：100 Percentile：89.14(Oceanography)An international sampling cruise, IAEA'97, was carried out in 1997 in the NW Pacif1c Ocean. The main results of this study are following: (1) The levels of oceanographic parameter showed differences from the historical data, (2) Transuranics water profiles showed typical sub-surface concentration maxima with decrease in concentration by about a factor of 4 from the historical results, deepening their positions by about a factor of 2 and declining the water column inventory by about 20% over 24 years, (3) Sr-90 and Cs-137 data confirmed that the observed changes in concentration profiles have been resulting from the regional water masses circulation, and (4) The concentrations of these radionuclides in surface water after 40 years of their main introduction to the NW Pacific are still showing a latitudinal dependence. The results present the most comprehensive recent study on the distribution of radionuclides in the NW Pacific Ocean with the implications for behaviour of these radionuclides in the water column and physical forcing of water mass circulation over the last 24 years.
Aramaki, Takafumi; Watanabe, Shuichi*; Kuji, Tomoyuki*; Wakatsuchi, Masaaki*
Geophysical Research Letters, 28(20), p.3971 - 3974, 2001/10
Times Cited Count：14 Percentile：37.15(Geosciences, Multidisciplinary)Vertical profiles for radiocarbon were described around the Bussol' Strait for the first time. The uniformity of radiocarbon concentration at 0-400 m depth in the Bussol' Strait was observed, and expected that diapycnal mixing occurs by tide between the sub-surface water around the Bussol' Strait and the surface water in the Bussol' Strait. The Okhotsk-Pacific cross-sections through the Bussol' Strait of radiocarbon concentration and density suggested the intermediate water in the Sea of Okhotsk has the role of the Okhotsk-Pacific water exchange, and the deep water between the Sea of Okhotsk and the Pacific Ocean is mixed well rapidly through the Bussol' Strait. Using estimation of bomb produced C-14 inventories in each water column, it was suggested the quantities of the Okhotsk-Pacific water exchange may be essentially small.
Togawa, Orihiko; *; Mizushima, Toshihiko; Yabuuchi, Noriaki; Kobayashi, Takuya
JAERI-Research 98-062, 50 Pages, 1998/10
JAERI-Research-98-062.pdf:3.49MB
no abstracts in English
