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152
RADIATION STANDARDS, INCLUDING FALLOUT
Chairman Houtrtevp. In any event, you would make this informa-
tion knownto the public?
Dr. Cuapwicx. Yes, sir.
Chairman Hourirtetp. And the area that it would affect first would
be the infants or the young children because of the need of calcium
for bone structure or the iodine uptake, and therefore, it might be
entirely feasible that children below a certain age might be tem-
porarily taken off milk and the older population could use the milk
without deleteriouseffects, relatively speaking?
Dr. CuHapwicx. Indeed, this is the suggestion that has been made
by the British Medical Research Council, that under certain condi-
tions in which expected annual accumulation of iodine 131 would
reach a certain level, the British Medical Research Council has recommended that infants in this age group be placed on some kind of
canned or powdered milk.
Chairman Hotirtetp. There was one incident at Windscale in England where they had the reactor excursion accident in which the
pasturage was contaminated to the point where they absolutely took
everyoneoff milk for a time period,is that not true?
_ Dr. Cuapwick. Yes. They actually dumped milk and disposed of
it.
Chairman Houtrtevp. Until the radiation went down?
Dr. Cuapwicr. Of course, it is quite clear that that milk could
have been held. In other words, it could have been put into some kind
of.processing such that radioiodine would have decayed out of the
milk.
I think they simply went to great lengths to take effective and complete action in the situation.
Chairman Howtrtetp. They exercised supercaution, you mightsay ?
Dr. Cuapwick. I think you are quite right.
Mr. Ramey. How does your range III for iodine 131 for the general
population compare? Is there any comparable figure for employees
in the radiation industry as a maximumpermissible intake?
Dr. CuHapwicx. There are really three factors that would makethe
amount that one would permit radiation workers to take, greater than
the general population.
First of all, there is the fact that the Hmitation of the intake of
radioiodine is based upon the concentration of the radioiodine in the
very small infant’s thyroid, which is a factor of 10 below the size of
the adult thyroid. So, given the same given intake, the infant would
receive 10 times the dose simply because of the fact that the energy
would be released in a gland of one-tenth thesize.
Secondly, the general population is restricted to a lower value than
radiation workers. In geueral, this has been a factor of the order of
10. Finally, there is an additional factor here in the case of radioiodine. The thyroid gland in adults has been shownto be a relatively
radioresistant organ.
In the case of children, the evidence would suggest that the thyroid
is not a relatively radioresistant organ. That isa sort of double nega-
tive there. In other words, there is not that factor of radioresistance
in the thyroid of the infant or child as compared to the adult.
So whereas the thyroid gland in radiation protection standards for
radiation workers is permitted a greater dose than the general run of
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