Water pumped, tritium concentration

In October, 1977 a higher capacity pump was installed in RNM-2S and pumping was resumed at a rate of about 2.27 m per minute. Significant amounts of tritium were finally detected after a total of about 1.44 million m of water had been pumped. The concentrations are still rising rapidly as shown in Figure 6. A number of pressurized samples have been taken and show Q Kr as well as HTO and HT. These data are summarized in Table VIII. The observed Kr/T atom ratios are very similar to that of 1.2 X 10 calculated for the Cambric source term, consistent... 

Figure 6. Tritium concentration as a function of volume of water pumped...

Provided the natural production of 5TU is the only source of tritium in the groundwater, we would have at hand a water dating tool. For example, water pumped from a well with 3TU has preserved 3 x 100/5 = 60% of its natural tritium content, equivalent to an age of 9 years (readable from Fig. 10.1). However, a hydrologist s life is not that simple. Most aquifers have a capacity equal to several annual recharges, or, in other words, water accumulates in the aquifer for many years and the age we have just calculated from the tritium concentration is not a real age, but rather an... 

The described observations may be applied to practical problems. For example, the weighted average tritium concentration in Vienna was 3280 TU in 1963 (Fig. 10.3). How much tritium would be left in water that was recharged in 1963 and pumped in a well in 1988 The answer can be found by using the following steps ... 

Fig. 4.17 Tritium and 14C measurements during a pumping test conducted in a confined aquifer at the Aravaipa Valley, Arizona (Adar, 1984). Recent water of high tritium and 14C concentrations intruded from the overlying phreatic aquifer.

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