Tritium method

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The tritium method is an inexpensive analysis method using the hydrogen isotope tritium . The main areas of application are mineral water hydrogeology , in order to obtain detailed insights into the mineral water cycle, as well as oceanography and limnology , in order to obtain more precise information about the flow patterns of waters. It is also used in historical research to date wines , water samples and water-containing finds from 1954 onwards.

application

Application in mineral water hydrogeology

In mineral water hydrogeology, the tritium method is primarily used as a tried and tested tool to optimize the management of mineral water resources. Measurements of the tritium content enable observations of hydrological systems on a time scale, which cannot be recorded in the same way by direct measurement methods. The central task is to determine the age of groundwater and mineral water. In the case of such bodies of water, one understands the length of time that the water stayed and circulated in the subsurface since the precipitation seeped into the subsoil. One speaks here of the so-called length of stay . It is a measure of the duration of the cleaning or filtering effect of the geological subsurface. However, since the precipitation from several years mixes in the groundwater or mineral water, it is not possible to calculate the exact retention time, which is why one speaks of an average retention time, or MVZ for short. Average residence times of a few years to several decades are possible, especially in determining the tritium content. Most of the tritium present in the hydrosphere today originates from the nuclear weapon tests carried out between 1953 and 1963. During the precipitation in these years, the tritium concentration rose by more than a thousand times its natural concentration; Since the mid-1960s, however, this has been steadily decreasing again due to the discontinuation of surface nuclear weapons tests.

In addition to dilution processes, this is primarily due to the radioactive decay ( half-life : 12.4 years). In Central Europe the tritium content is currently around 10 TU. A tritium unit (TU) is the proportion of one tritium isotope per 10 18 1 H atoms. At 1 TU a sample has an activity of 0.119 Bq / l.

Application in oceanography and limnology

The tritium method is also used in oceanography and limnology . By determining the tritium concentration in different water layers, it is possible to visualize the flow pattern of a body of water.

Application in historical research

In historical research it is possible to precisely determine water-containing finds after 1954 using tritium analysis. This method is especially used when dating wines. A natural amount of tritium is only found in wines made before 1954. This makes it possible to confirm the authenticity of an older vintage.

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