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ASSOCIATED UNIVERSITIES, INC,
Upton, New York 11973
Safety & Environmental! Protection Division
AO 1 See
(516) 345-4210
January 26, 1979
Dr.
Walter H. Weyzen
Manager, Human Health Studies Program
Division of Biomedical & Environmental Research
U. S. Department of Energy
Washington, DC 20545
Dear Dr.
Weyzen:
One of the key studies in the Dose-Reassessment for Rongelap and Utirik
is the determination of 1292 in soil samples that were collected from Rongelap
and Utirik soon after the fallout from the BRAVO test had ceased.
1291,
the
long-lived radionuclide, is the only isotope of the iodine series that would
still be present today in the above samples (collected in 1954) in detectable
quantities:
Knowing the concentration of 129{f in these soil samples and also
knowing the isotope fractionation (or ratios) for a given yield, we can
estimate the other short-lived iodine isotopes.
In addition, the iodine
isotope ratios could be used tO estimate other fission products as well.
However, the accuracy in determining the 129I concentration depends on the type of
sample used.
The historic samples analyzed in this study, so far, have been
soil samples collected from Rongelap.and Utirik by the University of Washington.
It is to be noted that the amount of fallout particles in such samples is
extremely small when compared to the bulk of the particles that make up the
soil sample.
In such cases,
the analytical method must be extremely sensitive
to detect very small quantities of 1291 in the sample. However, a "pure"
fallout sample as exemplified by the "Bikini Ash''(1) which fell on the Japanese
fishing vessel "The Lucky Dragon'' would be an excellent sample to analyze for
1297 and thus serve as a benchmark to which other samples could be compared.
this connection, the procurement of a small sample (3-5g) of the "Bikini Ash”
in
|
would be extremely useful in strengthening the accuracy of our
297 determination
in the historic soil samples.
Also, the data would prove useful to the Japanese
authorities who have studied the sample extensively but have not yet analyzed
the same for 1297,
Also, the reciprocity of our analytical data would indeed
benefit all in the true characterization of the fallout particles
from the BRAVO
test.
The samples, I believe, are in the custody of the Institute of Physical
and Chemical Research, Japan.
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