From a view point of health physics, studies on tritium behavior in the environment are necessary for an accurate dose assessment ; such as actual HT oxidation in the local environment, transfer of HTO to soil, plants and animals, and OBT formation and

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D2O release experiments Prof N. Momoshima,
Kyushu University, Japan

• From a view point of health physics, studies on
  tritium behavior in the environment are necessary
  for an accurate dose assessment such as actual
  HT oxidation in the local environment, transfer
  of HTO to soil, plants and animals, and OBT
  formation and tritium elimination in them.
• However, field experiments on environmental
  behavior of tritium are quite difficult to do
  because of the public acceptance problem in
  Japan.
• Thus heavy water (D2O) vapor release experiments
  was planed and carried out.

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Grants-in-Aid for Scientific Research from the
Ministry of Education, Science and Culture, Japan

• Environmental Behavior and Biological Conversion
  of Tritium -Preliminary Release Experiment of
  Heavy water in a Greenhouse-
• 19951996
• Transfer of tritium to crops, animals and fishes
  during an accidental release of tritium and its
  retention
• 1997-1999
• Prof. M. Ichimasa, Ibaraki Univ. Japan

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Members of the program and joined to the D2O
experiments (red)

• M. Ichimasa (Ibaraki Univ.)
• Y. Ichimasa (Ibaraki Univ.)
• H. Takeda (NIRS)
• S. Hisamatsu (Akita Univ.)
• H. Amano (JAERI), M. Atarashi
• H. Noguchi (JAERI), S. Yokoyama
• N. Momoshima (Kyushu Univ.), H. Kakiuchi
• T. Okai (Kyushu Univ.)
• Y. Sakuma (NIFS)
• M. Saito (Kyoto Univ.)
• A. Ito (Hiroshima Univ.)
• K. Komatsu (Hiroshima Univ.)
• K. Okuno (Shizuoka Univ.)

Transfer of D2O to soil, plants and animals, and
OBD formation and tritium elimination
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A greenhouse was constructed in the field of the
Ibaraki University. Closed type and top open type.
Closed type (1995-97 and 1999)
D2O
Top open type (1998)
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1995 1996 1997 1998 1999
Size 12.8m3 23.3m3(3.6mLx3.6mWx1.8mH) 23.3m3(3.6x3.6x1.8m) 62m3 (two cylinders)5.74mDx2.4mH 23.3m3 (two houses)(3.6x3.6x1.8m)
Date 3-4 Nov. 24-26 Aug. 23-25 Aug. 22-24 Aug 22-24 Aug
Release 24h 48h 48h 9h (daytime)11h (nighttime) 8h (daytime)8h (nighttime)
1.3L (20D2O) 4.5L (20D2O) 17.9L (20 D2O) 19.5L daytime14.9L nighttime20 D2O 20 D2O and 13CO2
3.6x104 ppm 2.2x104 ppm 1.2x104 ppm 8500 ppm (daytime)8100 ppm (nighttime) 3300 ppm (daytime)10600 ppm (nighttime)
Temp (?) 13.1-27.9heater 17-30Air conditioner (2) 20.6-27.9Air conditioner (4) 22-27 (daytime)20.5-22(nighttime)No control 29.6-34.1 (daytime)19.6-23.6 (nighttime)Air conditioner (4)
RelativeHumidity 61 (48-69) daytime71 (67-73) nighttime 8/24 81 '72-88) daytime8/25 75 (60-80) daytime8/24 88 nighttime 65 (37-70) daytime66 (62-69) nighttime 42 (32-56) daytime94 (84-97) nighttime
Light 11/4 1300-1500103 umol/s/m2 (20-690) 8/25 1300-1500222 umol/s/m2 (79-460) 8/24 1300-1500283 umol/s/m2 (41-620) 189 umol/s/m2(33-671) 158 umol/s/m2 (23-370)
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Atmospheric D2O concentrations in the close type
greenhouse (1997).
48h release
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Atmospheric D2O concentrations in the top open
type greenhouse(1998).
The D2O concentrations changed with time due to
wind and did not reach to a steady state. A large
difference in concentration with height near the
D2O humidifies but not so much apart points.
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Topic of research

• Uptake and release of D2O by plants
• rice, radish, tomato, komatsuna, cabbage, orange,
  soybean, (maze, potato)
• Uptake and reemission by soil
• Sandy soil
• OBD formation
• rice

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List of publications related to D2O experiments

• Deposition of D2O from air to plant and soil
  during an experiment of D2O vapor release into a
  vinyl house, Mariko Atarashi, Hikaru Amano,
  Michiko Ichimasa, Yusuke Ichimasa, Fusion
  Engineering and Design 42 (1998) 133140
• Formation and retention of organically bound
  deuterium in rice in deuterium water release
  experiment, M. Atarashi-Andoh, H. Amano, H.
  Kakiuchi, M. Ichimasa and Y. Ichimasa, Heaoth
  Physics, 82, 863-868 (2002).
• Uptake of heavy water vapor from atmosphere by
  plant leaves as a function of stomatal
  resistance, M. Atarashi, H. Amano, M. Ichimasa,
  M. Kaneko and Y. Ichimasa, Proceedings of
  International Meeting on Influence of Climatic
  Characteristics upon Behavior of Radioactive
  Elements, Rokkasho, Aomori, Japan, October 14-16,
  1997, Edited by Y. Ohmomo and N. Sakurai, IES,
  236-242 (1997).
• Conversion rate of HTO to OBT in plants, M.
  Atarashi-Andoh, H. Amano, M. Ichimasa and Y.
  Ichimasa, Fusion Science and Technology, 41,
  427-431 (2002).
• Uptake kinetics of deuteriated water vapor by
  plants Experiments of D20 release in a
  greenhouse as a substitute for tritiated water,
  N. Momoshima, H. Kakiuchi, T. Okai, S. Yokoyama,
  H. Noguchi, M. Atarashi, H. Amano, S. Hisamatsu,
  M. Ichimasa, Y. Ichimasa, Y. Maeda, Journal of
  Radioanalytical and Nuclear Chemistry, Vol. 239,
  No. 3 (1999) 459-464
• Uptake of deuterium by dead leaves exposed to
  deuteriated water vapor in a greenhouse at
  daytime and nighttime, N. Momoshima, R.
  Matsushita, Y. Nagao and T. Okai, J. Environ.
  Radioactivity,88, 90-100 (2006).
• Organically bound deuterium in soybean exposed to
  atmospheric D2O vapor as a substitute for HTO
  under different growth phase, M. Ichimasa, T.
  Maejima, N. Seino, T. Ara, A. Masukura, S.
  Nishihiro, H. Tauchi and Y. Ichimasa, Proceedings
  of the International Symposium Transfer of
  Radionuclides in Biosphere Prediction and
  Assessment-, Mito, December 18-19, 2002,
  JAERI-Conf 2003-010, 226-232 (2003).
• Heavy water vapor release experiment in a green
  house Transfer of Heavy water to tomato and
  dishcloth gourd, M. Ichimasa, T. Hakamada, A.
  Li, Y. Ichimasa, H. Noguchi, S. Yokoyama, H.
  Amano and M. Atarashi, Proceedings of
  International Meeting on Influence of Climatic
  Characteristics upon Behavior of Radioactive
  Elements, Rokkasho, Aomori, Japan, October 14-16,
  1997, Edited by Y. Ohmomo and N. Sakurai, IES,
  243-248 (1997).
• Organically bound deuterium in rice and soybean
  after exposure to heavy water vapor as a
  substitute for tritiated water, M. Ichimasa, C.
  Weng, T. Ara and Y. Ichimasa , Fusion Science and
  Technology, 41, 393-398 (2002).
• Deposition of heavy water on soil and reemission
  to the atmosphere, Sumi Yokoyama, Hiroshi
  Noguchi, Michiko Ichimasa, Yusuke Ichimasa,
  Satoshi Fukutani, Fusion Engineering and Design
  42 (1998) 141148
• Re-emission of heavy water vapor from soil to the
  atmosphere, S. Yokoyama, H. Noguchi, Y. Ichimasa
  and M. Ichimasa, Journal of Environmental
  Radioactivity, 71, 201-213 (2004).

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Rate constants and mostly cases Cmax/Cair were
obtained for various kind of plants
Uptake CpCmax (1-e-kt)
Release CpCo e-kt
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• Deposition of D2O from air to plant and soil
  during an experiment of D2O vapor release into a
  vinyl house, Mariko Atarashi, Hikaru Amano,
  Michiko Ichimasa, Yusuke Ichimasa, Fusion
  Engineering and Design 42 (1998) 133140

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OBD formation at daytime and nighttime
Formation and retention of organically bound
deuterium in rice in deuterium water release
experiment, M. Atarashi-Andoh, H. Amano, H.
Kakiuchi, M. Ichimasa and Y. Ichimasa, Health
Physics, 82, 863-868 (2002).
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OBD formation at daytime and nighttime
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The dead cedar needles taken up more D2O than
fresh ones both in daytime and nighttime
exposures. The release rate was faster in dead
cedar needles.
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Four kinds of leaves were exposed to D2O at
daytime and nighttime in 1999.
Fresh leaves dried at 80 C were rewetted for 3
days and the biaxial leaf surface was exposed.
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??????
Run Exp. Temp RH
D2O conc. (?)
() (ppm) Daytime-1 1h
32.3?33.3 58?61 13700 Daytime-2 1h
34.2?36.0 57?59 12200 Nighttime 2h 23.2
99 16300
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Uptake of deuterium by dead leaves exposed to
deuteriated water vapor in a greenhouse at
daytime and nighttime, N. Momoshima, R.
Matsushita, Y. Nagao and T. Okai, J. Environ.
Radioactivity,88, 90-100 (2006).
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F Vex ? (Ca - r ? h?Cs) Vexexchange rate
(m/s) CaHTO conc. in air (Bq/m3) rHTO
H2Ovapor saturation ratio (0.92) hWater
content at leaf surface (kg-H2O/m3-air)
CsHTO conc. in leaf (Bq/kg)
Cinnamomum camphora 10kV(top)?30kV(below)?magnific
ation 3500 Stoma size 20-30µm
Re-wetted
Dry
Air
H2O
D2O
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1996