These soil characteristics are recorded in the Tech Advisor's log for each of the 189 petri dishes

prepared (49, 69, 71 for X-1, X-2 and X-3, respectively). The soil characteristics were grouped by
depth for each plot area. Only those characteristics which predominated are shown in Figure B-9-2,
because of the subjective nature of the data.
All three plots exhibit a surface layer of brown sand and soil containing some root matter; however,
the depth of that layer was greatest (40 em) for the X-1 plot and least (20 cm) for the X-3 plot.
Plot X-2 showed the shallowest layer of soil, only about 30 em thick, prior to hitting the gray and
coral sand layer which continued to the 100 em depth. Plot X-3 showed the thickest layer (about 40
em) of dark brown soil, also assumed to be the richest soil. Coral sand regions were noted from 50
to 60 cm below the surface in Plot X-1 and X-3, while the same layer in Plot X-2 was observed only
30 cm below grade.

The average and range of 137Cs, 241Am and TRU concentrations, in pCi/g dry weight, observed
from the IMP screening data and lab analyses are presented below for the surface sample A and B
composites and 5 em deep profiles.

137 Cg*

241A m*
Range

TRUt

Location

Average

Range

Average

Average

Range

X-1

340

150-640

30

9-72

97

X-2

86

57-120

14

4-24

No Analysis

X-3

270

160-430

24

11-48

No Analysis

42-210

* Approximate values based on IMP screening at Ursula.

+ Sum of 238, 239, 240py and 241 Am (gamma) from lab analyses.
These values are based on an assumed moisture content of 10% for the IMP screened samples and

actual dry weights for those samples counted in the lab.

The subsurface concentrations for 137Cs and 241Am are presented in Figures B-9-3, B-9-4 and

B-9-5 for each of the plots. As expected, the data suggest that essentially all of the 137Cs and
241 4m are contained within the upper soil-sand layers and not in the coral sand below about 50 to

60 cm. Both the 137Cs and 241Am concentrations decrease with depth below the surface. An

order of magnitude decrease in concentration was observed in the first 15 to 20 em for 2414m and
in the first 20 to 30 em for 137Csg,

B-9-7

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