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.