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“SUMMARY
The Problem
To determine the amount and distribution of radioactive material re-
maining on several atolls and incorporated into plants and animals two
years after their contamination by fallout from the 1 March 1954 nuclear
detonation of Operation CASTLE.
Findings
Readily detectable amounts of radioactive contamination were found
in Marshall Island animals, plants, water and soil samples.
An increase was observed in the activity of coconuts, compared with
the results of a survey made one year ago (about one year post-detonation),
Some samples of portulaca, coconut husks, pandanus keys, pandanus
air roots, a clam, and certain potable water contained levels of ©
strontium-90 which exceeded the maximum permissible concentration.
The gamma radiations over the atolls decreased by 80 per cent over
the past year.
This loss of activity was attributed to radioactive decay
rather than the migration of nuclides to deeper layers or their erosion
into the surrounding water.
The activity in fish was almost 25 per cent of that determined at the
one-year post-detonation survey.
.