1376, (4.5 em) in the residential areas has little effect since that action
influences only the external gamma dose.
Removal of successive 15 cm layers
of soil in the subsistence agricultural areas, however, may reduce the bone
dose by significant amounts.
Removal of the top 15 cm layer, for example,
may reduce the 30 year bone dose from 57 Rem to 19 Rem, while removal of an
additional 15 cm may bring the dose down to 10.7 Ren.
Since soil removal-vs-bone dose reduction would possibly be most effective
for pandanus and breadfruit, a variation on the estimates of Table 9 may be
obtained by preferentially stripping soil in areas where these trees are
to be grown.
For case D-1, for example, if pandanus and breadfruit are
grown in the subsistence agricultural areas only in sections from which 15 cm
2.
7
ne
ah;
fs
Vae
ns
of soil have been removed, the resulting bene dose may drop from 57 Rem to
ty
GC?
St
9
Fos
Pe ee
FU
17
ON
he
.
Tr
re
nen
wand
.
additiconsl
as
om
1
the dese may drop to 23.7 Ren.
The maximum dose reduction that can be
achieved is through importation of clean soil from the southern isiands or from
outside the atoll.
90... concentrations in the average profile(Table 6)
do not get as low as those on the southern islands even at a depth of
180 cm.
To achieve this meximum effect, however, sufficient clean soil has
to be imported to encompass the entire root system of the mature trees and
the water supply for these crops must not have 906, levels higher than those
found in the southern islands.
granular.
Any replacement soil should be coarse and
Such soil is less likely to blow away or wash away.
Given these
conditions, the 57 Rem bone dose of case D1 may be reduced to 18.9 Rem
(57-39.1 + 2.1 (0.45)
(the 2.1 Rem from Table 241 and 0.45 from Table 243
of NVO-140).
SL at at
Cat
F make at,