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Hello Harro,

We do observe the same phenomenon you have described with regard to hydrogen
and oxygen isotope ratios in blood samples from *human subjects*.

Our baseline hydrogen values (delta VSMOW) from human subjects vary from
-45permil to -15per mil while our tap water is measured at -85permil.

Our oxygen values (delta VSMOW) from human subjects vary from -11per mil to
-2 permil while our tap water is measured at -9 permil.

We are also interested to hear other list members' input on the above.

Regards,

Nabil Saad
Kinemed, Inc.



On Dec 14, 2007 11:26 AM, Bowen, Gabriel J <[log in to unmask]> wrote:

> Hi Harro,
>
> Food is an important source of H and O to the body water, as is
> atmospheric O2 through metabolism.  In general, I would expect the opposite
> of the pattern you describe below...body water d18O should be relatively
> heavy due to metabolic (+23.5) and dietary (ca. +10 and greater)
> contributions, whereas the d2H should be not too dissimilar from drinking
> water (plant and animal tissue d2H is only moderately 2H-enriched relative
> to environmental water).
>
> There is a lot of published work on 18O in body water, for a good example
> w/ some synthesis see Bryant and Froelich, GCA: 59, 4523-4537, 1995.
>
> Podlesak and colleagues have also published some relevant data in the
> latest issue of GCA: 72, 19-35, 2008.
>
> Best,
> Gabe Bowen
>
> -----Original Message-----
> From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On
> Behalf Of H.A.J. Meijer
> Sent: Friday, December 14, 2007 10:53 AM
> To: [log in to unmask]
> Subject: [ISOGEOCHEM] 2H and 18O values for "blood" water and body tissue
>
> Dear colleagues,
>
> 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
> per mil.
> 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!
>
> best regards,
>
> Harro
> --
>
> 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
> http://www.rug.nl/cio
>