RE: Naturally-occurring Tritium

[Franz Schoenhofer <schoenho@via.at>]

At 08:10 15.02.2000 -0600, you wrote:
>Franz,
>
>Perhaps you or someone else can answer a simple question for me regarding
>this topic.  I have seen a few hydrogeological studies that claim to be able
>to "date" ground water by the amount of tritium in it.  Is there really an
>adequate understanding of tritium in the environment to support this?
>
>Doug Minnema, Ph.D., CHP
>Defense Programs, DOE
><Douglas.Minnema@ns.doe.gov>
>

Hi,

This question is not so simple. As far as I know, tritium is a very
important tool for doing hydrogeological research and the ones doing this
work claim, that they can date the water. It obviously needs a very
thorough knowledge of the groundwater systems involved. The easierst case
would be of course when one does not find any tritium in the water. Then
the conclusion is clear: this is very old water, which had been shut off
from any replenishment for at least 100 years (half life of tritium is
about 12 years). Mixing phenomena with recent precipitation can be studied
taking into consideration the amount of tritium being present and comparing
it to the theoretical value, which would have to be expected. The highest
input of tritium into the (northern) hemisphere happened in 1963 and 1964.
This was a kind of "marker". It seems to me very complicated and I do not
know any details. 

There are other isotopes which can be used in dating ground water, for
instance Kr-85.

Franz


Franz Schoenhofer
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e-mail: schoenho@via.at


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