18
the greatest likelihood of the presence of plutonium.
The
values given in Table 14, therefore, probably are maximum values
for each type of sample.
The ratios of
239,240__
Pu
to
238 Pu
approach 2:1 at Eniman I. and are about 15:1 in Bravo Crater.
Bikini I.
soils contained no detectable 238 ou,
although they
contained the highest concentration of 239,240), u of the samples
analyzed.
The presence of 239,240), and 20754 in goatfish viscera
is consistent and probably results from direct ingestion of fine
particles of sediment during feeding.
The absence of 2385 in
goatfish viscera as compared with the sediment merely reflects
a low concentration of this radionuclide, below the limits of
detection.
Although none of the 1969 samples were analyzed for the
X-ray emitter O3n4,
this radionuclide was found in concentrations
of 80 a/m/g dry weight in Bravo Crater sediment collected in
1967
(Beasley and Held,
1969).
Nickel-63 is of particular interest
as a tracer since it has a half-life of 92 years.
In addition,
the clam kidney accumulates 63u4,
and is there-
as it does 6000,
‘
63...
fore an indicator organism for the presence of Si.
Another long-lived radionuclide,
1
‘
08m,s with a half-life
of approximately 100 years, has been identified for the first
time among the radionuclides at Bikini.
This radionuclide was
detected from the gamma-ray spectrum of the hepatopancreas of