NV/HEG Mtz.-Sept. 26-27, 1968
Page 6
same for a given oral intake.
This amounts to a ten times larger dose
to the 2-gram thyroid of a one-year-old child compared to an adult's
thyroid which weighs 20 grams.
Therefore,
one-year-old children were
considered by the FRC to be the critical segment of the population.
For instance,
the doses to the thyroid gland of people on Rongelap were:
adults, approximately 160 rads from iodine,
from fallout;
and children,
external gamma.
175 rads from external gamma
700 to 1400 rads from iodine,
175 from
Severe damage to the cells of the child's thyroid
normally resuits in hypothyroidism.
This condition hinders growth,
results in poor metabolism, the cholesterol goes up, hardening of the
arteries develops sooner, and possibly even carcinoma.
There is some confusion regarding maximum permissible dosage of I-131.
The National Bureau of Standards Handbook gives the maximum permissible
body burden for the thyroid as
.7 microcuries; total body is 50.
Federal Radiation Council put out a
The
level of 80 to 100 picocuries per
day intake for a year as a maximum allowable dose for children.
The ICRP
listed 700 picocuries total per liter of milk intake for adults.
Another
set of figures by the FRG for population groups contains 1.5 rem per
year to the thyroid for an individual who is not a radiation worker but
the RPG for an average of a suitable sample of exposed
ae
is 0.5 rem per year.
population group
SNL
"A suitable sample is considered to consist of
'
children of approximately one year of age, using milk fron2 reasonable
homogeneous supply."'
For radiation workers it is 30 rem per year or
10 rems for 13 weeks.
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