-18-
infrared heat lamp,
110 c/m after flaming and 4 c/m after covering
with aluminum foil 4.7 mg/cm? in weight.
of
A total correction factor
112 was used (based on a secondary Fe° standard obtained from
Dr. C. A. Finch, University of Washington) to convert to disintegrations per minute.
The radioisotopes of zinc, cobalt and manganese were identified by
their gamma energies and the disintegrations per minute were calculated from the
gamma spectrum curves of the different fractions.
Radiostrontium was not detected in the citrate fractions whereit
would be expected to occur.
Radiochemical precipitation determinations revealed the presence
of small amounts of radiostrontium in the bone of fish collected at
Kabelle Island.
No radiostrontium was detected either in the liver or
muscle of any of the fish taken at Ailinginae or Rongelap Atolls or in
the bone of fish from Enibuk Island or Rongelap Island.
Table 6 con-
tains data on the Sr?9 contentin fish tissues collected during and since
1954 at Rongelap Atoll by this Laboratory.
Except for traces of Sr90
in goatfish and reef fish bone from the Kabelle Island 1957 collections
and in bonito bone from the 1955 collections at Labaredj, no radiostrontium has been detected in the fish tissues.
A summary of the data on the radioisotopes obtained from the liver
tissue sample of reef fish from Enibuk Island is contained in Table 7.
In total radioactivity, Zn§5 contributed about 40 per cent, CoS? Cos,
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