- 24 -
The decay rates of algae from the
are given in Table 8.
intertidal zones of eight islands
In general the decay rates for the different species
collected at one island were the same.
It was found, however, that the
decay rates varied depending on the date of collection.
The radioactivity
in the algae collected at Henry and Leroy Islands decayed faster than that
inthe algae collected at other islands ( Table 9).
Table 9.
Summary of the decay rates of algae collected on four dates
at Leroy and Henry Islands,
bined,
Date of
collection
and at six other islands com-
expressed as the negative slopes of logarithmic plots.
Leroy Is.
Henry Is.
Other islands
6/3/54
1.8
1.5
1.3
7/20/54
2.0
2.0
1.5
10/54
2.6
2.3
1.3
2/55
2.7
1.7
1.1
From these data it appears that the algae at Leroy and Henry Islands absorbed radionuclides with relatively short half lives.
A similar
conclusion was reached with samples of invertebrates collected at
same time 8) nation
from
activity at
of the atoll.
the
These observations indicate that the residual contamiprevious
detonations
accounted for less of the radio-
these islands than it did at the islands in the northern end