resulting fits were worse than when the original data were used
(correlation of logs was 0.77 and 0.11 for
tively).
2355
and
238
U, respec-
Both 2351 and 2381 concentrations for soil and vegetation increase as
one approaches ground zero.
The increase in vegetation concentration
proceeds at a lower rate, however, than that for soil.
This is
reflected in the decreasing ratic of vegetation mean to soil mean
2354 and 238i,
given in the last column of Table 1 for
This same
239-240 Pu in vegetation and soil by
phenomenon was reported for
Romney et aZ.
(1975, Table 2) for the other safety-shot sites.
Romney attributes this decreasing ratio in higher activity strata to
differential particle size distribution that occurred within the
fallout patterns of these events.
The ratios themselves are of the
same order of magnitude as observed for
The average concentrations of 2
239-240 Pu at the other sites.
34U and 236 U (Table 2) for vegetation
are approximately 100 times less than the vegetation concentrations
for 235y and 238 U (Table 1).
There is a modest increase in these
concentrations for strata near ground zero.
The average vegetation
concentrations for total U is about the same for strata 2 and 3,
which are about twice the level of stratum 1 (Table 2).
The estimated inventories of
235 U an d 238 U in the surface 5 cm of
soil for A Site are given in Table 3 as 1,045 + 274 and 10,500 +
1,150 grams, respectively.
Using the 10 samples (2.5-cm increments)
from a single profile sample in stratum 1 of A Site, which we believe
to contain only natural uranium (see the footnote to Table 3 and the
discussion in the next paragraph), the total amount of natural 2354
and 238) present in the top 5 cm of A Site soil was estimated to be
61.9 + 3.5 and 8,630 + 47.4 grams, respectively.
the strata inventories,
By subtraction of
the inventory resulting from only the safety
shot was found to be 983 + 274 and 1,920 + 1,150 grams for 2354 and
2387 | respectively.
Note, however,
that the standard errors of these
latter estimates are very large, resulting in approximate 95% confidence limits of from 395 to 1,570 grams for 2354 and from -564 (or
zero) to 4,400 grams for 2385
More information at other locations
in A Site is needed to verify our estimates of mean concentrations
130