In contrast restricting the population to only areas 3 and 4 (Case IV)
results in very low integrated exposures.
For comparison purposes, the mean integrated dose to the Northeast
U.S. population (~80 mrad/year ) are also shown in Table IV.
We note
that even for the most exposed groups (Cases I and III) the calculated
30 year
population doses are Likely to be only a few times that
received by the Northeast U.S. ‘population.
If one considers the
mean dose to the etx entire returning ‘population assuming 25% of
the people will be represented by Case I (a and b), 25% by Case II
25% by Case III and 25% by Case IV, as shown in Table IV, then the
mean exposure for 30 years is only 50% greater than that for the
U.S. population.
De
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i
The preceding discussion assumes no modification of the present
radiation fields.
It is general practice in Micronesia to cover the
village areas with 1 to 2 inches of coral rock (Tobin).
This action
can be expected to reduce the exposure levels in the village area
by approximately a factor of two. ‘The second row of doses for each
case in Table IV reflects this modification.
Since clearing the islands for agricultural use and housing will
result in some mixing of the top soil and since plowing all of thé
islands to a depth of about 1 foot would not appear to be impractical,
we also calculated the expected modification in dose due to an assumed
uniform mixing down to this depth. !
mixing than in burying the topsoil:
(Plowing presumably results more in
Were the present topsoil to be
covered by 12" of relatively inactive soil, this would reduce all
-3- .
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