and BM = sieved line.
This conclusion is not surprising in view of
the large scatter due to low Pu concentrations. At these low levels,
considerably more data would be required to detect differences between
BM and sieved results.
Some information is also available on plutonium concentrations in
<100 mesh
(sieved)
and >100 mesh fractions of the same soil sample.
The BM fraction can be separated into these two fractions, and if it
were shown that their Pu concentrations were not different,
this
would cast doubt on the results reported above that sieved and BM
fractions do yield different Pu concentrations.
In Fig. 14, the
logs are plotted for 21 pairs of mean 239-240 Pu concentrations
obtained on <100 and >100 mesh soil fractions of profile samples. The
<100 mesh data are given in Table 4, Library numbers L11617 through
L11637, inclusive.
The mean >100 mesh concentrations for 14 of the
21 samples are given in Column e of Table 8.
The remaining mean
239-2405, results for >100 mesh are given in the footnote on this
page.’
In all but three samples (L11625, L11626, and L11637 in Table
8, Columns b and e), the <100 Pu concentration is greater than the
corresponding >100 Pu result for the same sample; i.e., the ratio A/B
(Column k,
Table 8)
is greater than 1.
Some of these ratios are very
large, considerably larger in most cases than the ratio of <100 mesh
to BM fraction (Column 1, Table 8).
This is expected since the BM
fraction contains both the <100 and >100 mesh fractions.
In Figs.
15 and 16 are plotted the available 238 Pu and 241am results for these
same soil samples.
239-240
The general conclusions are the same as for the
Pu data.
In all three figures, the estimated 95% confidence
region for Bg and B, does not include 8, = 0, 8; = 1. In other
words,
the <100 mesh concentrations are significantly elevated over
the >100 mesh concentrations,
and the ratio is not constant over the
range of concentrations considered.
What can one tentatively conclude relative to Question 1?
First, for
most data sets investigated, the Pu concentrations in BM fraction
aliquots are not equal to those in <100 mesh aliquots, at least for
"111622, 0.0784; L11627, 3.80; L11628, 0.290; L11629, 2.49; L11632,
1.45; L11633, 0.325; L11634, 0.955.
147
Units are nCi/g dry.