RESULTS AND DISCUSSION
North-South Transect Samples
In the earlier report
samples were given.
(Tamura,
1975a),
results of analyses of nine
In addition, the locations of three additional
samples along the north-south transect in Area 13 were given.
Analyses
of 10-g subsamples of the three additional samples (labeled 6A, 6B,
6C) showed the plutonium concentrations to be 296,
136, and 145
disintegrations per minute per gram (dpm/g), respectively.
The
analyzed samples excluded gravel (greater than 2-mm particles),
because the assumption was made that the plutonium contribution from
gravel is negligible.
Calculated concentrations of plutonium, however,
did include the weight contributed by gravel in order to maintain
consistency with other investigators on the project who normally
grind the total soil sample prior to analysis.
In Fig.
1,
the log of the plutonium activity is plotted against the
log of the distance from GZ.
The best-fit equation for the relation-
ship was found to be the logarithmic relationship:
Y = 1.26 + E+
-2.07) where Y is the activity in dpm/g and X is the distance in
feet; the term E + 9 is 107.
In addition to the original nine samples
along the transect and the three additional samples located from
1,900 to 3,600 ft from GZ,
the mean concentration of plutonium in the
samples taken near Site 2 for comparison of vegetated versus nonvegetated conditions is plotted.
Note that Sample 6C contained 145
dpm/g, which is higher than anticipated; however, this type of anomaly
is to be expected in large-scale field situations under variable
atmospheric conditions.
=
-
Results of the particle size distribution of 6A,
in Table 1.
6B,
and 6C are given
The particle size distribution of all three samples
appears to be more closely related to that in the surface soil of
Site 6 than of Site 7, which were previously reported (Tamura, 1975a).
The plutonium distribution in size fractions less than 2 mm is given
in Table 2.
The activity (dpm/g) for each size fraction is presented
in Row A.
As in previously reported samples of the north-south
transect, the 53-20 um size contains the highest concentration of
Plutonium.