MODIFICATION OF D AND O-18 CONTENT OF WATER SAMPLES DUE TO EVAPORATION FROM LEAKY CONTAINERS

Isotope effects accompanying evaporation of water samples stored in leaky containers were investigated in some detail. It was confirmed that isotope enrichment of the remaining water is in agreement with predictions of the existing isotope models of evaporation processes. The best agreement of model predictions with the experimental data was obtained when maximum values of kinetic enrichment parameter epsilon-k were adopted (28.5% and 25.1% for O-18 and D, respectively). This indicates that in this particular case a fully developed laminar sublayer persisted close to the evaporating surface, controlling fractionation of the heavy isotopes. The isotope enrichment rates observed in the experiments (0.35% and 1.0% change of O-18 and D content, respectively per 1% change of the mass of evaporating water sample) can be applied for eventual correction of isotope results, for a wide range of storage conditions. The experiments carried out in this study allowed more precise assessment of the role of different parameters in the modification of D and O-18 isotope composition of the evaporating water bodies.