25.5 ISOTOPIC EXCHANGE OF TRITIUM IN THE PROCESS OF WILLOW VEGETATION

UDC 550.47:550.424 📖 Issue 25 / 2016 • 49-55 pages

 

V. Bobkov, V. Dolin

V. Bobkov Ph. D. (Chem.), Senior Researcher, SI «Institute of Environmental Geochemistry of .NASU», VBgeochim@i.ua
V. Dolin D. Sc. (Geol.), Professor, Head of Department , SI «Institute of Environmental Geochemistry of NASU» vdolin@ukr.net

Abstract

In a model greenhouse experiment the peculiarities of tritium migration from the water phase of the habitat into components of white willow (Salix alba L.) and isotope effects of hydrogen during the vegetation have been studied. The rate constant of tritium transfer through the root system to the intracellular sap of plants is 2.17±1.45•10-6• s-1. The tritium balance between external water and intracellular sap has been come to the equilibrium during 1-2 weeks. Thus, the fractionation factor (α) is 0.88 – 0.94 and does not depend on the concentration of the superheavy isotope of hydrogen in external water. The rate constant of the transformation of tritium in organically bounded species is 8.6±3.0•10-7 s-1. The equilibrium is set for 4 to 11 weeks, α = 0.17 – 0.19 and does not depend on the concentration of the superheavy isotope of hydrogen in external water. At the same time, the extraction of the radioactive isotope from the system, probably owing to transpiration has been observed. The value of rate constant of Tritium transpiration calculated from experimental data is 2.67±0.27•10-8 s-1. The rate of tritium transpiration is proportional to it concentration in external water. The coefficient of tritium fractionation during transpiration is 1.2.

 

Key words: tritiated water, willow, intracellular sap, organically-bounded Tritium, concentration, rate constant.

 

Article



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