In addition to the tuna from the Japanese fishery, sixteen
yellowfin tuna, believed to be from a single school, were caught
off Bikini Atoll in the Marshall Islands in September 1969.
Liver samples,
not obtainable from the Japanese-caught fish,
and
light muscle and dark muscle from these fish were analyzed for
gamma-emitting radionuclides,
iron-55 and stable iron.
The samples were counted for 900 minutes each with 3-inch x
3-inch Nat(Tl)
analyzers,
crystals used in conjunction with 256-channel
Spectrum reduction was done by Schonfeld's
method of least squares,
(1965)
and all values were corrected for decay
to the date of collection.
Iron-55 was separated and purified by a combination of
solvent extraction and electrodeposition techniques
Beasley,
1967).
Recoveries generally exceeded 90%.
(Palmer and
Counting was
done by X-ray spectroscopy with a proportional counter used in
conjunction with a multichannel analyzer.
Some duplicate samples
were analyzed by different persons using different methods,
ard
the results were in close agreement.
RESULYS
The values for
55
.
tuna had a wide range.
Fe,
The ranges for dark muscle were
to 1600 pci/g dry weight;
oo.
aclivity,
.
toes
tos
.
stable iron and specific activity in
.
0.02 to 8.6 nCci
iron, 49 to 500 ppm;
35
Fe/mg Te.
55
Fe,
and specific
3.3