Strontium-89 has the same chemical properties as strontium-90 and
will follow the same metabolic paths.
quantities than strontium-90.
It is created in much larger
However, it has a shorter half-life
(53 days) and emits beta particles with about one-half the energy of
those from strontium-90.
For these reasons strontium-89 content in
milk may peak at values many times that of strontium-90 during the
periods immediately following nuclear tests, yet the total radiation
dose to the bone over a lifetime from strontium-89 may be only one-quarter
that of strontium-90!-.
the Data ~
About 21 million curies of strontium-90 have been created by
atmospheric nuclear tests with about 17 million curies of this being
spread globally.
The other 3 million curies fell quickly in areas
local to the testing sites.
To dete, roughly 8-9 million curies of
strontium-90 have been deposited globally, leaving a calculated 6
million curies in the region of the atmosphere below 100,000 (based
pot
on measurements using aircraft and balloons) and one million curies
above this level - estimated by extending the observed datal3-.
The
discrepancy in total numbers is due in part to radiological decay of
strontium-90 but more because of uncertainties in the estimates themselves.
As expected, the peak value of "strontium units" in milk was passed
in June of 1963 (32 "strontium units" as a national average) !4-,
In
the absence of atmospheric tests these levels are expected to continue
te