-

10

-

There is no indication that a similar increased uptake would occur
in young children.

Special calculations of dese resulting from ingested plutonium have
not been made for the infant or child.

The available data on metabolic

behavior of the transuranic elements in the infant and child indicate
that no significant underestimate of hazard will result from considering

the total population as adults.
Because of the very long retention of transuranic elements in man,

most of the radiation dose deposited in infants or children will be delivered
when the child has grown to a much Larger size.

The radionuclide is not

only diluted by this growth process, but, in the important instance of bone,
is buried under new bone growth and its alpha particles largely shielded
from the radiosensitive cells on the bone surface,

Thus, the smaller intake

of radionuclides by the infant or child results, over the life span, in a
very much smaller dose than the metabolic models predict using adult intake
parameters.
Page 9, line 25 to Page 10, line 10 - "In addition the uptake of
americium in soils by vegetation is substantially higher than plutonium

uptake.

Similarly americium is readily taken up from the gastrointestinal

tract and accumulated in the liver, spleen and bone of mammals, and thus
undoubtedly in man.

"Based on these considerations it is possible that uptake of americium

in the food chain and its accumulation in the liver and skeletal tissue of

man may be the critical path for exposure to internal alpha emitters in the
Enewetak Atoll area.
+
Comments:

The use of 241an data in the dose evaluations for Enewetak

Atoll in "Enewetak Radiological Survey," NVO-140, 1973, are as follows:
Marine Food Chain - 241 an data were included in the dose assessment.

24]an was non-detected in most of the fish samples analyzed.
the value used for assessment was the detection Limit,

In such cases

Select target paragraph3