Re: [Phys-l] Isotope chemistry and physics

[Bernard Cleyet <bernardcleyet@redshift.com>]

The problem w/ low toxicity of all sl. toxic materials is whether  
they are cumulative, such as UV, or not, such as Cs-137.  I suspect  
the bio-half life of D2O is rather long **, therefore, any additional  
ingestion (above that naturely occurring) is not recommended.  True  
for immediate pathology the concentration must be great, but if it's  
cumulative, I'd rather not increase our present unavoidable exposure.

** for the D that is incorporated in cells -- why children,  
especially, should not be fed D.

I think the below site is credible:

http://www.physlink.com/Education/askExperts/ae685.cfm

Regarding the naturely occurring isotopes being toxic:  I suspect  
we've along w/ our jillion years ago ancestors have had time to  
adjust to the sl. reduced chemical activity of the denser isotopes.   
But not to a sudden change in the concentration of D2O.  An  
interesting experiment would be to do the reverse, i.e. subject mice  
or better, bacteria to an environment containing only the lowest  
atomic weight isotopes, a reverse poisoning.  [Obviously fanciful,  
but a thought.]  the bacteria would evolve, but not the mice in the  
lab. time scale?

bc believes in the precautionary principle.

p.s. A, ha, selective quoting.  Here's an alternate one:

 "Non-toxic levels of heavy water reduce induced hypertension and  
associated changes in rats (Vasdev et al., 1993; 1994). A patent has  
been obtained for the use of heavy water in treating human subjects  
(Liepins, 1993)."



It is, at bc's level of understanding"  that because the nature of  
toxicity of heavier isotopes is reduced reactivity.  One might be the  
selective action of the kidneys in production of urine, i.e.  
concentration of D20, similarly to the concentration of mercury by  
sword fish and shellfish.






On 2009, Mar 16, , at 10:34, John SOHL wrote:

> In BC's original reply there was a link below the D2O statement  
> (see Bill's note below):
> http://www.isb.vt.edu/brarg/brasym96/kushner96.htm
>
> In that paper there is the statement:
> **
>
> Since this conference is largely concerned with the risks of  
> releasing different substances into the environment, it should be  
> stated at the beginning that D2O itself poses little such risk--so  
> long as it has not been used in nuclear reactors. As will be seen  
> below, D2O itself is not toxic to animals, except under exceptional  
> and very improbable circumstances.
> **
>
> This matches my understanding and I'm assuming Bill Nettles'  
> understanding. The paper does go on to note that in nuclear  
> reactors the D changes to T which is radioactive and is thus a  
> clear risk.
>
> As far as I know, the biggest risk in drinking D2O is to your  
> pocketbook.
>
> All the best,
>
> John
>
>
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> John E. Sohl, Ph.D.
> Professor of Physics
> Weber State University
> 2508 University Circle
> Ogden, UT 84408-2508
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