3.8
SUMMARY AND CONCLUSIONS
Studies of animals provided data on the nature and distribution of the radioisotopes in the
tissues and the excreta. Over 90 per centof the activity in the body of animals was localized
in the skeleton. The pattern of deposition of the fission products in the skeleton seen in autoradiographs resembles that of the alkaline earths. Morphological changes which were observed
in some of the bones may be the result of the exposure of the animal to radiation, although the
effects of severe dietary changes and disease cannot be ruled out.
The alkaline earths, Sr® and Ba!4? and the rare-earth group together constituted 75 per
cent of the gross beta activity in the pig at 82 days postdetonation. The fish and clam had a
much lower concentration of the alkaline and rare earths, and a body burden considerably
higher than that of the land animals.
The internal distribution of fission products in the pig is probably representative of the
distribution in human beings. An estimate of the human body burden was derived from the data
on pigs.
Studies made on egg production of contaminated hens gave no evidence of any effect of radiation. The rate of production of the eggs was normal, and the eggs produced were also normal, The extraordinary ability of fowl to mobilize calcium in shell formation resulted in the
presence of very high activity in the shells of the first few eggs. The activity was associated
with the fission products of the alkaline-earth group. A significant amount of activity was found
in the yolk and lesser amounts in the albumen. The removal of activity from the body of chickens
by egg production provides an effective natural decontamination process.
Fertility of the hens and hatchability of the eggs produced by the mating of contaminated
roosters and hens showed no effect of radiation. The baby chicks hatched from these eggs are
growing normally, and the amountof radioactivity in their tissues is barely detectable.
Although the administration of the combination of zirconium citrate and sodium EDTA to
chickens doubled the excretion rate of fission products, the rate at this long time after exposure
was so low that the body burden waslittle affected.
In the six-month period postdetonation neither significant gross changes nor pathological
changes that could be definitely ascribed to radiation were detected in any of the animals from
Rongelap. Gross beta activity of urine and tissue samples indicated that all the animals had
significant internal contamination. Thelevel of internally deposited radioisotopes in the pigs
from Rongelap was 10 times the amount in human beings from this area. The difference in the
amount of internal contamination of the animals and the human beings was the result of the
prolonged stay of the animals in the contaminated area. The chickens were found to have the
same concentration of radioisotopic material per unit of body weight as the pigs.
All the animals remaining will be observed throughouttheir lifetime for the possible appearance of any long-term biological effects resulting from their exposure to external and
internal radiation.
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