Re: tritium stratification

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

Thermodynamic stratification due to gravity occurs over very long
distances and would not explain concentration stratification in a
pond.  In large bodies of water like an ocean you probably can
detect a difference in tritium concentration, but it would come about
because the half-life of tritium is small compared to the mixing
time of surface and deep water (if I remember corectly the time scale
for mixing is about 10,000 years).

If you observe stratification I would look at two possibilities, some
of which may have been touched on by others.  The first would only
apply in an unlined pond where you might have a spring feeding "old"
water into the pond.  Here you might expect tritium to be depleted
at depth relative to surface water.  In the second case I would
suspect that the tritium entered the pond in a chemical form other
than as hot water.  In this case you might find a mechanism for the
chemical to plate out on the bottom e.g. amino acids might be integrated
to little critters that die and deposit on the bottom.  The tritium
might then be slowly released and create a higher concentration
near the bottom assuming the mixing time is relatively long compared
to the release rate.

Dale Boyce
dale@radpro.uchicago.edu