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BOXNo.
COLLECTION AG 326
26-78 °3
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De. John C. Bugher, M.D., Director
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AQSBRO
Division of Biology and Medicins
R
Gordon MW. Dunning, Health Prysicist
‘Biophysics Breneh, Division of Biology and Medicine
ESTIMATED RADIATION DOSE TO THYROID OF NATIVES FROM RONGELAP
This memorandum is in reply to your request for an estimate of
additional doses to the thyroid of the Rongelap natives due to the
fact that tellurium, as a precursor to iodine, may be present in
the gut after ingestion of fallout material. The telluriu, in
turn, might disintegrate into radioactive iodine while in the gut,
with subsequent deposition of the iodine in the thyroid.
There are some 17 radioactive isotopes of tellurium but only 7 of
these are produced in fission. Of these, 6 are not of interest
(4 have too short a half-life, 1 leads to stable_iodine-127 and 1
NO ODE CLASSE om
remaining radiocisotepe is tellurium132, with a half-life of 77 hours
leading to iodine-132 with a half-life of 2.4 hours. (Incidentally
Without having the original data of LASL I have accepted their
estimate that there were ingested and/or inhaled the products of
5x10
fissions, assumed they were all ingested,
and then proceeded
to calculate the dose to the thyroid from (a) r3i (ob) each short-
reid
Liyse iggine isotope of interest and (c) the added dose coming from
-143¢, The calculations show that 7132.7132 will produce an
=o
added dosage of about 26%.
The best estimated percentage absorption and deposition of Lodine is
oe
pate: 4 a
yet to be determined.
The best estimate I can turn upto date is
still the 20% quoted in NBS Handbook 52.
‘3 J =-
= =
there is no tellium precursor that is of interest here. )
However, I will contime to
search for additional information. In the meantime the table below
indicates the magnitude of doses to the thyroid if one assumes 20,
SO, and 100% absorption and deposition.
REVILWER (FQ).
NADAE.
TAIED
CATON ¢ 1ANGEO TO
_ =
SINGLE REVICW AUTHORIZED BY.
DEPARTMENT OF ENERGY DECLASSIFICATION AEVIEW
DETERMINATION (CIALLE NUMBERS}
leads to iodine-129 with a half-life of 2-4 x 10’ years). ‘he
Incidentally, it may be
noted that the calculations below based on 20% (the number assumed
by -LASL) show estimated doses to the thyroid from 131 and from
shorter lived fodine isotopes to be in goed agreement with those
estimated by LASL, i.e., 50 reps for q131 and 80 reps for short-
4
lived iodine isotopes.
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