In making these dose reduction approximations, one must keep two things
in mind; first, that the NVO-140 doesestimates for terrestrial foods grown on
an island such as JANET are based on correlations between certain indicator
plants and average soil concentrations in the 0-15 cm samples (Fig. 3) since
foods such as pandanus and breadfruit were not found on JANET and, second,
that these concentrations are averaged over the 0-15 cm depth of Figs. 4 and 6.
Estimates of dose reductions to be expected due to removal of soil to a given
depth, therefore, require an estimate of the ratio of the average concentration

of the nuclides of concern in the 0-15 cm depth of the newly exposed surface
to that for the surface which is present now.

This approach does not consider

the radioactivity in the soils deeper than 15 em which may be important,
particularly for plarts with roots that penetrate deeply into the soil.

Table 3

presents these average concentrations and ratios for 905, and 13706 for each 15 cm
increment from the present surface down to 105 cm as derived from Figs. 4 and 6.
These estimates indicate, for example, that removal of 15 em of soil may reduce
the terrestrial food dose due to 905 by a factor of 3.3 and that due to
1376, by 3.2.

However, such reduction may or may not be actually achieved.

Using the data of Table 8, one may assess the dose reductions that might

occur due to specific cleanup actions on JANET.

Table 9 shows the doses

that might occur due to seven different conditions.

Case Drepresents

the contributors to the 80 Rem bone dose of Table 2 using values for 900, and
1376, averaged over all of JANET.

Case DJ-‘indicates that if subsistence

agriculture is limited to the area shown in Fig. 2 (i.e., along the lagoon
shore) the 90. and

137

Cs levels may be reduced to such an extent that the

resulting 30 yr bone dose becomes 57 Rem.

Removal of a half-thickness of

040

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