Water tritium

Isotopic-labeled tracers behave like the components in the fluid of interest. For example, tritium water behaves like water. If less similar chemicals are used as tracers, selective adsorption, chemical reaction, and liquid-liquid distribution must be considered. The tracer must be chosen so that the analytic method is sufficiently sensitive to detect the tracer in the desired amounts. 

Engesgaard P., Jensen K. H., Molson J., Erind E. O., and Olsen H. (1996) Large-scale dispersion in a sandy aquifer simulation of subsurface transport of environmental tritium. Water Resour. Res. 32, 3253-3266. 

Gvirtzman H. and Magaritz M. (1986) Investigation of water movement in the unsaturated zone under an irrigated area using environmental tritium. Water Resour. Res. 22, 635-642. 

Tritium water HjO, denoted as HTO, is non-adsorptive, so it is appropriate to check the applicability of our analysis. The diffusion coefficient of HTO in free water is reported as 2.44x10" cm /s=769.48cm/year (Klitzsche et al, 1976). 

For example, HT released from a plant is rapidly oxidized to HTO. Tritium water may be incorporated in organic matter as organically bound tritium (OBT) within tissues. The specific radioactivity of tritium in the form of CH3T in the atmosphere is very high, hut the reason is not understood. C may be released to the atmosphere as CO, CO2, CH4, HCHO, and COS. C02 released becomes incorporated into crops via photosynthesis leading to enhanced levels of C in crops. 

Since tritium water HTO is not adsorptive (see later), we can set Kd=0. Then... 

Tritium water HTO ( H20) consists of a tritium atom, which is an isotope of hydrogen, an oxygen atom and a normal hydrogen atom. The chemical property is almost same as the normal water H2O, and in a bentonite saturated with normal... 

We assume that the profile of diffusivity of tritium water HTO is the same as the normal water shown in Fig. 9.12 however, its diffusivity in the bulk water is specified by experiments as 2.44 x 10 cm /s at 25°C (Klitzsche et al. 1976), therefore the maximum value in Fig. 9.12 is replaced by this experimental value. The diffusivity in the clay mineral is, of course, nuU. 

Two reindeer (Rangifer tarandus) were placed in stalls located within controlled environment chambers, and 1(X) xCi HTO was injected into their jugular veins. Periodically, blood samples were inspected for radioactivity. This study of body-water volume and turnover was conducted using 12 different combinations of diet and temperature. A comparison of water-flux rate, as determined with HTO, to measured water input showed a linear relationship (Figure 48). The investigators (Cameron et aL, 1976) concluded that the tritium water dilution technique provided accurate determinations of total-body-water flux over the wide range of experimental conditions in reindeer. 

Cameron, R. D., R. G. White, and J. R. Luick. 1976. Accuracy of the tritium water dilution method for determining water flux in reindeer (Rangifer tarandus). Can. J. Zool. 54(6) 857-862. 

The formation of an enediol intermediate is supported by the observation that one of the carbon-bound protons of RuDP was labilized by the carboxylation enzyme and would exchange with tritium-labeled water (J. Hurwitz and W. B. Jakoby, unpublished observation). PGA formed in the presence of COj and tritium water also contained tritium. 

---