Uptake of elementary tritium by the soil

On the basis that soil is an important 'sink' of elementary tritium after its release to the atmosphere, an experiment is described in which tritium is brought into contact with the surface of 10 cm deep undisturbed field soil cores. The deposition velocity vsub(g) is calculated from the decrease of the HT concentration in the air of a closed gas circuit. It was found that HT is converted mainly to HTO in the upper centimetres of the soil. About 0.1% is taken up by soil microorganisms as non-exchangable organically bound tritium (OBT) during the first week of exposure. The significance of varying climatic conditions on vsub(g) and the water content of the soil are discussed. (author)