x
- 48 . saturated sodium carbonate wee added to 100 cc of sample, the sample
then filtered through millipore filter paper, and the precipitate ashed and
counted.
The purpose of the sodium carbonate was to remove naturally
- occurring K49 (approximately 540 d/m/liter) from the precipitate.
Tests
performed by the Health and Safety Laboratory, New York Operations Office,
on this technique indicate that potassium does not co-precipitate and that
‘from spikes using 18-month-old mixed fission products , only 23 percent of
The counting error per unit weight is
:
olen ae
10
__ the activity escaped precipitation®~.
‘considerably less in the "treated" column because of larger sample size and
a smaller correction for self-absorption.
Values in the "untreated" column for the October collection indicate
some radioactivity in the Kabelle sample, but a questionable amount of
activity in the three other samples.
However, the values in the "treated"
column definitely indicate activity in both the Kabelle and Labaredj samples.
The best estimate of the maximum value of mixed fission product activity
; : ; {n Rongelap lagoon water is 0.0006 uc perliter. |
The island water samples were prepared for counting by drying both an |
unfiltered and filtered sampie.
Thefiltered sample was passed through a
millipore filter and both the filtrate and the residue were counted.
One
hundred-ce samples were used without difficulty as there was very little
residue remaining on the plates after drying.
However, the well sample
from Rongelap Island had some salts and from the weight of the salts it
_ Was estimated that 8 percent of the sample was sea water.
The well water on Rongelap Island was less radioactive than cistern water.
-
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