Dear Harro,
I agree with your observations regarding highly enriched 2 H and 18O in 
local natural range in blood (water
 component) in humans and animals . There may be only two sources of H 
(water and food) while three sources of O (water, food and air through 
respiration). As the intake of O is very high through respiration (Air that 
contains local natural O-18) in case of every living being, therefore, in 
normal conditions the O-18 should be near to local natural air in blood 
while 2H should be enriched as lighter molecules of water are removed more 
through swetting (skin pores) and urine (filtration through Kidney) causing 
2H enriched in blood. However, the enrichment in 2H will be region specific 
depending upon the weather conditions. The isotopic data of swet and urine 
may support my hypothesis of 2H enrichment.


BK
*************************************************************
Dr. Bhishm Kumar
Scientist F & Head
Hydrological Investigations Division
(Previously Nuclear Hydrology Division)
National Institute of Hydrology
Roorkee - 247 667 (Uttarakhand), INDIA
Phone: (O)  +91-1332-276414
             (R) +91-1332-275970
Fax:            +91-1332-272123
E-mail: [log in to unmask] ; [log in to unmask]
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Coordinator
Coastal and Deltaic Regional Centre
National Institute of Hydrology
Siddarth Nagar, Kakinada (A. P.), India
Phone:               0884 2372254
Phone and Fax:  0884 2350054
e-mail: [log in to unmask]
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----- Original Message ----- 
From: "H.A.J. Meijer" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, December 14, 2007 9:22 PM
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
>