rey
~~ SERENE 8. RRR HS A:
ow
29
ecicentrations were initially estimated by using the approximating: total
aicha X f = plutoniur.
Although the initial results of these analyses were
only of secondary significance to the purpose of the thesis topic, the data
.as analyzed further arter the measurements of plutonium, americium, uraniun,
radium and polonium in surface sediments were available.
The goals were to
evaluate the accuracy of the raptd total alpha measurement technique employed
and
to estimate the absolute concentration of total alpha radioactivity in
the sediments.
Because these goals were met with some success, the methodol-
ogy and data resulting from this work are included in Appendix 1.
Selected
data from Appendix 1 can thus be discussed (section 5.4) without introducing
unnecessary data to the main topic of the thesis.
4.1-2
Sample dissolution
Surface sediments and selected sections of sediment cores
which had been previously gamma counted were dissolved in boiling concentrated
nitric and, occasionally, hydrochloric acid.
The sample was then wet-ashed
with perchloric and nitric acids, evaporated to dryness, redissolved in dilute
(> 4M) nitric acid and filtered through a #42 Whatman filter paper into a
volumetric flask.
Any insoluble material remaining on the filter paper was
treated to a second wet-ashing, boiled twice in concentrated HF, and treated
to a NaoC03-Na0H fusion.
The fusion products were dissolved? in dilute HNO3,
filtered into the volumetric flasks and subsequently made up to 500 ml with
dilute nitric acid.
a. A minute amount of insoluble residue remained after the HF/fusion
treatment. Seven of the filter papers containing this trace residue
were analyzed for plutonium.
was 0.5 pCi/filter.
The highest
¢39+240py concentration measured
Typically, the concentrations were 0.1 pCi/filter.