ss
menerionr ¢
EVPECYR OF 10NIEING RABIZTITR
Thes internal -nntami-
netian reenited fram bath inbalation and ingre-
tren of fatlen moterval.
High levels of activity were found in water
and on the cuternal surfaces of planes. The
Pommbnenvation 8 the wntcce
es)° ssrttionz
ot
xe
of Sroits
ledime is probably
the mont Sezrdow: internal radieemitter st
early time after exposure. The dese to the
thyrond, although greater than tolerance, was
lew compared tothe partially or teteily sb
tating: Qin of T°
uein ite icwacmem of
and vequtables was mail. (f the individual
hyperths ruedinm of carrinsmea.
ty and relatively lang radioactive half-life was
probebly the isntope of greatest potential hazard in the environment.
Few of the fission products present in the
environment were readily absorbed from the
thon of se” wan calculated to be arar the maxi-
ratiornectiden, Se”, borane of its high solebil-
Nee cep eet
to 1) rep fur Bongelap.
lungs and the (7. I. tract. Radiochemical analysis of the urine samples from the Rongelap
people indicates that Sr. Ba and the rare earth
group together constituted 15 percent of the
total beta activity of the urine at 45 days post
detonation. Sr® was the predominant radionuclide at this time, contributing 42 percent of
the total beta activity. Assays for fimile material in the pooled urine samples were negative
The human body burden of indivigual radio-
At ane day post detonation, the roncentre-
mum permiwsible level for this nuclide. At
later times following exposure, this longer-lived
timion product presenis the greatest potential
internal hazard.
Oral administration of calcium EDTA be-
ginning ¢ weeks post detonation to a represent-
ative group of individuals from Rongelap ia-
creased the rate of excretion of activity 2.5
times. However, the decrease of the body burden was slight, as the excretion rate was very
low at this time.
Analysis of the internal contamination indicates that the dose to the tisue of the body
was near, but, with exception of the dose to the
nuclides was estimated from radiochemical
analysis of the human urine and of the tissues
thyroid, did not exceed the maxinum permis-
mean beady burdens of the radionuclides in the
Ailinginae group were approximately one-half
these of Rongelap. and the mean body burdens of the Americans about one-fourth of the
Rongelap group. While the activity excreted
per unit volume of urine was the same for adults
and children from Rongelap, the total activity
_ exereted in the urine in 24 hours by children
wider To ye moof aye was symiticantly lower
contribution of the effects of internal contami-
and urine of animals from Rongelap. The
than that ex oted by the adults.
The total amenuat of radionctive material in
the Ga To trvct at one day post detonation was
estimated to be Sime in people from Rongelap.
This activity was contributed chiefly by isotopes
of short: radiologieal and biological half-life
and hited solubility, and thus the levels of ac-
tivity in the tissues of the body were relatively
low. The concentration of radioisotopes at 6
months post detonmehon was barely detectable in
the urine of mest of the exposed individuals,
The estimated ose to the thyroid from 2?
and other short lived tadine Isotopes was 100
sible dove levels.
The activity tized in the body
decreased rapidly as a function of time. The
nation to the total radiation response observed
appears to be small on the basis of the estimated
hody burden of the mredioelements, In view of
the short half-life of the most abundant fission
products in the situation, the possibility that
chronic irradiation effects will occur is small.
5.4
Internal Contamination of
Animals
Var Dsteanat Contamination of a number of
animals collected on Rongelap was studied. The
vetivaty in their urine was stuclied, and radio
chennent analyses were made of various (issues.
These data provided the basis for estimating
the body burden of the madioisotopes in human
berg. In addition. nematologieal and pathological studies were nade. and autoradiographs
of selected tissues were prepared. A] number
of the animals are also bemy studied for the
TE A taneens amelie Ohcae