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D2O release experiments Prof N. Momoshima, Kyushu University, Japan.
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Prof. M. Ichimasa, Ibaraki Univ. Japan
Transfer of D2O to soil, plants and animals, and OBD formation and tritium elimination
A greenhouse was constructed in the field of the Ibaraki University. Closed type and top open type.
(1995-97 and 1999)
Top open type
Atmospheric D2O concentrations in the close type greenhouse (1997).
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.
Rate constants and mostly cases Cmax/Cair were obtained for various kind of plants
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) 133–140
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).
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.
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.
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 9916300
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).
Vex：exchange rate （m/s）
Ca：HTO conc. in air （Bq/m3）
r：HTO & H2Ovapor saturation ratio （0.92）
h：Water content at leaf surface
Cs：HTO conc. in leaf （Bq/kg）
Stoma size 20-30μm