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Saito, Tatsuo; Yamazawa, Hiromi*; Mochizuki, Akihito
Journal of Environmental Radioactivity, 255, p.107035_1 - 107035_14, 2022/12
Times Cited Count：0 Percentile：0(Environmental Sciences)The seasonal variation of dissolved U (DU) in Lake Biwa was reproduced by the following model and parameter research. The introduced models are the water-DU mass balance, and the ion exchange between UO
and H
on the lakeshore soil. The optimized parameters were the CEC of the lakeshore, TU as the sum of DU and AU (soil adsorbed U), kads and kdes as the first order reaction rate coefficients during rapid soil adsorption and desorption of U, respectively. Tabulated by the chemical equilibria constituting DU and analyzed the contribution of each chemical species, it is shown that the seasonal variation of DU is caused by the seasonal variation of pH. A correction to the ion-exchange equilibrium to shift to first order rate reaction only when the daily AU ratio increased above kads or decreased below kdes, improved the reproducibility of DU measurements and reproduced the delay of the DU peak from the pH peak.
Fu, F.; Watanabe, Kazuo; Yabuki, Sadayo*; Akagi, Tasuku*
Journal of Geophysical Research, 109(20), p.D20212_1 - D20212_9, 2004/10
Size-separated aerosol samples were collected at Tokaimura urban seaside area of Japan using an Andersen type sampler during July 2002 to July 2003. The size-separated aerosols were divided into water-soluble and insoluble fractions, and chemical compositions (Na, Cl
, NH
, NO, SO
, Al, Ca, Mg, Fe, Pb, Th and U) in both water-soluble and insoluble fractions were analyzed. Then, the seasonal variations and the size-distribution in mass concentration and chemical composition have been investigated in detail. Our results showed that the atmospheric aerosol in Tokaimura was obviously affected by dust storm in China, and that sea-salt particles were bigger than those in the Antarctic and were deficient in chlorine.
Be, 
K, 
Cs and 
Pb during 1993-2001 at Tokai-mura, JapanUeno, Takashi; Nagao, Seiya; Yamazawa, Hiromi
Journal of Radioanalytical and Nuclear Chemistry, 255(2), p.335 - 339, 2003/02
Times Cited Count：20 Percentile：77.2(Chemistry, Analytical)To evaluate the migration of radionuclides to the ground surface, deposition was collected from 1993 to 2001 with basin set up at Japan Atomic Energy Research Institute at Tokai-mura. Monthly basin samples were evaporated to dryness to obtain residual samples.These samples were measured by a well type Ge detector for natural and fallout radionuclide. These monthly depositions showed a clear seasonal variation with peaks in the early spring from February to April, and also in May in some years. The depositions of K and Cs have good correlation with the dry weight of deposited material, the depositions of Be and Pb showed much lower correlation coefficients. This difference in the correlation coefficient between these two groups of radionuclides can be attributed to the difference in the originating processes. These features in the concentration are thought to be caused by the difference in mechanism and location of origination, which would result in difference in the contributing particle size, and hence by the difference in the transport and deposition processes.
;
Hoken Butsuri, 20(2), p.109 - 119, 1985/00
no abstracts in English
