fnMl
vegetation is eaten in a small area or over a large one, the quantity of
fission produsts ingested is proportional to the area of plant surface
eaten rather than the groundevered, as long as the deposition was
similar and the animals ate in the same mamer.
One might assume this
for a sheep.
For humans, an effective (biological + radioactive) half life of
6 days is observeds thus the biological half life is scmewhat more than
simmly equal to the radioactive halflife as is here asaumed.
Thus
608X757 = ad
Set,
If this applies here, both a lower initial uptake and lower total
dose are implied by a given activity measured in the thyroid. The thyroid
dose calculated here imy thus be a generous estimate, On the other hand,
a lower uptake figure would put the figure of grasing and retention rate
assumed still further in disagreement with the figure for ground consentre-
tion based on the dose rates measured in the area.
Using the values of air dose rate ami q which have been discussed,
one may estimate the dose to the sheep from Shot 2 az was done in ref (1).
Here the dose rate at 2 hrs was 500 mr/hr. At 3.5 hours, this is
then
ey
With n= 1.2, this oguals 260 mrfhr, and u(t,) © 87(260) = 2300 pe/tt”
as in ref (1).
Then
~9-
ae,
noe ARCHIVES