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Eniwetok Atoll.
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In general those islands closest to the site of detonation
and in the downwind path of the fallout contained the highest levels of
radioactivity.
In March 1955, algae and bottom sand collected in the deep water
(20 to 140 feet) of the lagoon one half to two miles offshore contained as
much or more radioactivity than samples collected in the shallow water
near shore.
The ratios of amounts of radioactivity in the sand and algae
showed indirectly that the algae were concentrating radioactive material
from the neighboring water.
Comparison of decay rates of sand and
algae from the deep water showed that there was no selective absorption
of radionuclides by the algae.
Algae at Leroy and Henry Islands absorbed radionuclides with
shorter half lives than those absorbed by algae at the other islands of
Eniwetok Atoll, an indication that there was less residual contamination
from previous detonations at these two islands than there was at other
sites examined.
In general, certain genera of algae (Spyridia, Lyngbya, and Udotea)
contained more radioactivity than others,
while some (Halimeda,
Caulerpa, and Codium) usually contained the least.
There was no ap-
parent relationship between the amount of radioactivity in an alga and
its structure, habitat, or phylogenetic relationships.