Re: Strontium 90 vice Strontium 89

[Franz Schoenhofer <schoenho@via.at>]

At 16:33 10.08.2000 -0500, you wrote:
>In a message dated 8/10/2000 9:49:43 AM Mountain Daylight Time, 
>norco@bellatlantic.net writes:
>
><< The fallout argument is not
> sufficient because Sr-90 levels in baby teeth should be going down if the 
>Sr-90 was
> from fallout. Sr-90 levels in teeth in the Toms River area are at levels 
>equivalent
> to teeth tested in the late 1950s, when above ground testing was at its 
>height. >>

I have answered to this incredible nonsense in a posting to Norman, telling
him that I have previously already dealt in detail with this absolute wrong
statement about the height of above ground testing, also accusing him that
he never reads what is written to him. Now I see a RADSAFEr repeating this
nonsense without classifying it for what it is!


>
>Just from a layman point of view, has consideration be made for the change
in 
>technology since 1950.  

In 1950 practically no Sr-90 existed in the environment, because the
atmospheric nuclear tests showed their first results in detectable
contamination in the environment after 1955.

While I am not as familiar with the study as most, I 
>would believe there would be a greater statistical error and equipment error 
>utilizing 1950 era equipment and procedures as there would be today.  

No. Methods of radiochemical isolation of Sr-90 used nowadays are in
principle very similar to those used in the late fifties and after that -
chemical separation of Sr-90, measurement of Sr-90 or rather Y-90 after
establishment of equilibrium. Of course some modern methods have been
introduced, but most radiochemists have been extremely skillful in
producing reliable results. Many retrospective studies on the Sr-90
contamination of the environment have btw been done only recently, using
for instance (as we did) ultra low-level liquid scintillation spectrometry
and well preserved old samples of bones, antlers, baby teeth etc. We have
modern equipment, but the "old" radiochemists had their skills and also
time to perform the analysis correctly.

Is it 
>possible the Sr 90 was present, but not accurately accounted for?

Yes, it was present - everything else is impossible, but the analysis
performed at this time were similarily correct as the ones done recently
with the most modern equipment. 


Franz


Franz Schoenhofer
Habicherg. 31/7
A-1160 Vienna
Austria
Tel.: +43-1-495 53 08
Fax.: same number
mobile phone: +43-664-338 0 333
e-mail: schoenho@via.at


Please note my new telephone number at my office!

Office:
Ministerialrat Dr. Franz Schoenhofer
Federal Ministry of Agriculture, Forestry, Environment and Water Management
Radiation Protection Department (BMLFUW I/8 U)
Radetzkystr. 2
A-1031 Vienna
AUSTRIA

phone: -43-1-71100-4458
fax: -43-1-7122331

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