RYVECTS OF TONTRING RABATION
Qu the basis of an smumed ptabe of 3 por-
An attempt te measure hene-fined radiaertive
cout per 34 hours, the integrated dose to the
emitters hy means of sensitive film badges taped
mangpes was calculated by the USN REDE to be
en a nember of permses, yielded np postive
aad SM) rep for the Americans.
degree of internal contamination and the clint-
USNRDL and the LASL for estimating the
bacdy burden gave resulta which, except for
Ha', are very close.
short half-life of the most sbendant hanton
thyreid from f'’' and other shorter-lived iodine
about 110 rem The 1.0989. hee aerimeced thst
thes dase wes shoet |i) rep for Rengelap group
The differing approaches used by the
The mean body burdens of the individual
nuclides prevented in Table 5.6 were calculated
for the Rongelap group. Values for the
Ailinginae group were approximately half
thase of the Rongelap group, and values for
Americans, about one-fourth those of the
Rongelap group.
The tal amount of radioactive material
present in tie G. L. tract at one day post detona-
tion in the members of Group | was estimated
ax approximately (}ime. This activity was con-
trilnated chiefly ly ise Crp en of short radiological
and trological half-life and linuted solubility.
Thus the levels of activity in the tissues of the
badly were relatively low. The concentration
of radioisotopes at 6 months post detonation
was barely cletectable in the urine of most exposed individuals,
lodline, which is quite soluble, is probably
the ment hazardous internal radioemitter in the
early
period
following exposure
(10).
The
helow the knee, over the epiphysis ofthe tribes
No correlation coald be obtained bet ween the
cal and hematological findings.
In view of the
products deposited internally in this situation,
the possibility that chronic irradiation effects
will occur if quite small. Thas, an evaluation
of the data on the internal vontamination, inchading that of Se*, leads to the conclusion thet
the internal hazard to the contaminated inhabitants of the Marshall Islands is minimal both
from the acute and the long range point of view.
5.33
Source of leeernal Comtamsmation
The fallout material consisted largely of
calcium oxide and calcium carbonate. The
timion products were adsorbed mainly on fairly
large particles. The material was 10 percent
soluble in water, and completely soluble in acid.
Internal deposition of fission products resulted from inhalation and ingestion of the fallout material, Ingestion appears to be the more
important of the two routes of entry into the
badly. The activity in the air settles oat fairly
raptily, but contaminated fond, water and
utensils retain their activity for long penods of
dase te the Chyrou was appreciable, but low
compared to the partudly or totally ablating
domes Of Pused in therapy of hyperthyroidism
orcarcinema. At one day post detonation Sr”
was crleuleted to he near the maximum per-
time,
The amount of fission products reaching the
blondstream through the respiratory tract is a
tuisesble level (5) for this nuclide.
which the activity: was associated were considernbly larger than the optimum size for
deposition ini the alveolar tissue of the lung.
Thus, the probability of the retention of inhaled
airborne contamination was not appreviable
during the exposare period,
At later
tues following exposure, this longer-lived fisston produet prevents the grentest potential internal hazard.
The prevent study confirms the observation
Tiade thoan mal expertoeuts that most of the
ridiemetive clements formed in fskion as well
as the fissile material itself, are not rendily absorbed from he lungs and the GL. tract. Only
ioSr. Baane a few of the rare exrth elements
were ubserbed te any significant deyree.
function of paurticle size amd solubility of the
ninborne
contaminants.
The particles with
The hypothesix that ingestion was the chief
source of internal contamination is supported
by the finding that the gastrointestinal tract,
its contents, and the liver of autopsied chickens
and pigs sacrificed at early intervals following
eee
74