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Sr-90



Norm,
Coal fired plant do not put out Sr-90 unless if fell on a coal pile as
the result of atmospheric fallout.    However, they do put out Ra-226
which has the same chemistry as Sr because it is a naturally occurring
alkaline earth element with a radioactive half-life of 1600 years, and
as an alpha emitter produces more ionizations per emitted particle.  By
comparison, the half-life of Sr-90 is only 28 years.  Fossil plants also
put out uranium, thorium, polonium, and radioactive isotopes of lead.
Lead has been shown to proxy calcium in the body.  I believe that
uranium also may do the same. You can compare the relative radiotoxicity
of Sr-90 and Ra-226 by looking at their permissible concentrations or
Annual Limit of Intake (ALI).  I would do it but I do not have the info
handy.  So, I do not understand the current paranoia  with Sr-90 other
than it was of great concern in the 60s at the height of the atmospheric
weapons testing because of the levels found in milk.

Kjell Johansen
Whitefish Bay, WI
kajohans@powercom.net

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