peak was calculated.
This value was subtracted from the com-
posite .134 MEV and .145 MEV peaks in the samples.
The
remainder was considered to be from Cel41,
The values obtained for all isotopes were corrected to
the date of collection of the sample.
DISCUSSION OF RESULTS
Ocean survey samples
During the Collett survey (August 8 to 14) gamma spectra
were made on plankton samples.
Pronounced peaks at 0.055 MEV
and smaller peaks at 0.03 MEV,
later identified as those from
tungsten-185,
(Fig. 2).
were observed in some samples but not in others
When the station positions for those samples con-
tributing the
two peaks were plotted on a chart of the area
sampled, a pattern of occurrence was observed (Fig. 3).
The
plankton specimens containing the wi85 were taken in three areas.
The region containing the highest levels of wi85 in- the plankton
(19,000,000 d/m/g dry weight) centered 155 nautical miles
northwest of Eniwetok Atoll,
total radioactivity,
coincided with an area of high
and was about 180 miles in diameter, with
a tongue of activity extending to Eniwetok Atoll.
The northern
and western boundaries of the radioactive area were not determined.
A second area,
containing lower levels of wi85,
was
approximately 90 nautical miles west and south of Eniwetok and