My estimate for the isotope values for blood (that is the water
component) in humans and animals would be that it has to be pretty
close to the local (drinking) water. It is possibly slightly enriched
due to evaporation processes in the body as well as in the open water
available in nature for animals to drink, but not by more than a few
In the "bakground" samples we process for doubly labelled water
studies, however, relatively high values for 2H occur regularly,
sometimes higher than + 50 o/oo. 18O is always in the local natural
range that I expect.
Is this an artefact, i.e. contamination by memory effects in the lab,
or in the field, or during sample storage (samples are being stored
in flame-off capilaries)?. If so, why does it never happen for 18O?
Or is it real? We know that the hydrogen in body water interacts with
H in tissue to some extent, but can tissue be that highly enriched in
2H? And if so, why is it so variable?
Is there any experience with "blood water" isotopes in fields where
people do not use enriched water as well, f.i. in forensics?
Thanks on forehand for helping!
Prof. dr. Harro A.J. Meijer
Centrum voor IsotopenOnderzoek (CIO), Rijksuniversiteit Groningen
Nijenborgh 4, 9747 AG Groningen, Netherlands
tel +31-50-3634760 fax +31-50-3634738