Re: Dating of Water via Tritium Determination

[Schoenhofer <schoenho@via.at>]

At 02:00 22.01.1997 -0600, you wrote:
>Dating of water via tritium determination is normally done by enrichment of
>tritium in the sample, that is by the use of electrolysis.  There are only a
>few laboratories in the country that can do this.  These include the EPA
>laboratory in Las Vegas, Lawrence Livermore, the Desert Research Institute in
>Nevada and a few more.  It is not a precise method but can be used mainly to
>determine if water has mixed with surface water or was derived from surface
>water in the last few decades.  While at EPA a few years ago, I was curious
>about the tritium content of well-known mineral waters such as Evian and
>Perrier, and found that both had detectable tritium, meaning that the water
>had been to the surface in recent times. 
>
>                                                             Robert Holloway
>                                                             Nevada Technical
>Associates, Inc. 
>
>____________________________________________________________________


Dating of water cannot be done "by enrichment of tritium in the sample".
Only for achieving a very low lower limit of detection enrichment is used.
The dating is a process which does not only involve measurement of tritium,
but has to consider many other hydrogeological parameters. I am sure, that
quite a lot of competent laboratories exist in the USA, not only a few.
There are other means to date ground waters, like C-14 concentration,
O-18/O-16 ratios, even noble gases like Kr-85.

To detect mixing with surface water and precipitation in recent time, one
uses the occurrance of nitrate and pesticides in ground water - depending on
the hydrogeological parameters of the aquifer in question and the
environment, for instance whether there is a farmland region. This will of
course not work in areas, where no farming occurs. 

If I remember correctly hydrocarbons were found a few years ago in Perrier -
or it might have been another famous brand of French mineral water. This
confirmed that adfluence of surface water might have been occurred. 

My personal opinion is that it is one of these incredible nonsenses, to
import so called mineral water from overseas, even though a good supply of
acceptable water is in reach. I still remember how much I enjoyed a few
years ago an ice-cold bottle of "rock water" in Phoenix Arizona from a local
supply.

Franz

What is a yuppie? - It is a person, whose body consists of 90% Perrier.
Schoenhofer
Habichergasse 31/7
A-1160 WIEN
AUSTRIA/EUROPE
Tel./Fax:	+43-1-4955308
Tel.:		+43-664-3380333
e-mail:		schoenho@via.at