148
The concentration of 2385 reported in Appendix Tabie 5 is in a few
cases the resuit of swltiple determinations.
PBecausa these concentrations
era also determined somewhat differently from the procedure outlined in
section 4.2-4, the procedure used to calculate the concentration in these
samples is discussed selcw.
Early in the analytical work it was found that several samples had
239+240,
unusually high ratios of
mized for the
239+240
238
Pu/-~-Pu.
Because the sample size was opti-
Pu concentration, as estimated from the total alpha
measurements, the low chemical yields resulting at tnis early time resulted
.
in
23
.
.
.
.
woe
Boy concentrations in sone final samples at or below tne limits of
detection.
After modification of the separation prececdures so that larger
samples could be run with better chemical yields, aliquots of these
relatively very low
238
Pu concentration sediments, and others previously
analyzed, were rerun without the addition of a radiochemical tracer.
This provided én accurate means of determining the
233
Pu concentrations in
the samples where the 2385 concentration was originally below the detectior
limit, | and provided for an additional verification of the
2394240
pu/??8pu
ratios measured in samples for which this ratio had previously been
determined with a 236 Pu tracer added for yield determinations.
The
results of these comparisons are shown in Appendix table 4.
Inspection of the plutonium raticos obtained from the analysis of
spiked and unsnit.ed alisuots of tha same dissolved sediments shows that
with the exception of sample lo. C~4, the two ratios obtainea fer each
sample agree within a 1 S.D. deviation about the mean, based on counting
1 2385, 2394240), (
Pu
Ist aliquot)+
S9+2405, 238
/-~~Pu (2nd aliquot).