Abstract
The absorption and loss of tritiated water (HTO) vapor at bare soil and grass surfaces were studied in laboratory and field experiments. The exchange involves turbulent mixing in the air and diffusion within the soil.
In short exposures it was found that uptake by moist soil was controlled by atmospheric mixing and was described by an exchange velocity of about 1 cm s−1. The exchange velocity was a little smaller for air-dried soil and grass surfaces. For exposure times exceeding a few minutes re-evaporation reduced the rate of net uptake, but the total amount deposited continued to increase as the HTO diffused deeper into the surface. The diffusion coefficient for HTO in soil was investigated in the laboratory and a simple equation was derived to predict the effective diffusion coefficient.
Tritiated water, absorbed during a brief exposure, evaporated during several weeks. Its behavior was described by the diffusion equation, but unexplained discrepancies were found in apparent diffusion coefficients in field conditions. Rain washed the activity into the soil and impeded evaporation.
Most of the HTO vapor interacts with the surface within two or three days following a low level release. The effect of the surface exchange on the distribution of dose following a release of HTO vapor may be large, but will depend on the weather over a period of weeks and is difficult to foresee.
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References
Booker, D. V.: 1965,Q.J.R. Met. Soc. 9, 73.
Chamberlain, A. C.: 1966,Proc. Roy. Soc. A. 296, 45.
Chamberlain, A. C. and Eggleton, A. E. J.: 1964,Int. J. Air Wat. Poll. 8, 135.
Crank, J.: 1956,The Mathematics of Diffusion, Oxford University Press, London.
Curry, J. A.: 1960,Brit. J. Appl. Phys. 11, 318.
Liss, P. S. and Slater, P. G.: 1974,Nature,247, 181.
OECD: 1977, The OECD programme on long range transport of air pollutants: measurements and findings.
Penman, H. L.: 1940,J. Agric. Sci. 30, 437.
Smith, D. B., Wearn, P. L., Richards, H. J. and Rowe, P. C.: 1970, ‘Water movement in the unsaturated zone of high and low permeability strata by measuring natural tritium’. Proceedings of the Symposium on the use of isotopes in hydrology, IAEA-SM-129, p. 73-87. IAEA, Vienna.
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Garland, J.A. The absorption and evaporation of tritiated water vapor by soil and grassland. Water Air Soil Pollut 13, 317–333 (1980). https://doi.org/10.1007/BF02145476
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DOI: https://doi.org/10.1007/BF02145476