Laboratory investigations of HTO deposition to soils

Water vapor exchange between atmosphere and soil may lead to net deposition of HTO and H/sub 2/O as a result of their partial vapor pressure gradients, which are usually different for HTO and H/sub 2/O because of concentration differences in the two compartments. It was found from soil column experiments that the specific activity of the moisture deposit can be higher than that of the atmospheric humidity by a factor well above unity. This factor also describes the correlation between the deposition velocities of the two types of molecules. For radioecological consideration of this effect a model has been developed describing HTO and H/sub 2/O deposition and diffusion in relatively dry soil