-16-
time 1s one-eighth that of the pretest level; subsequently there
is an increase in activity.
Since both the total activity and
the long-lived activity increased by approximately equivalent
amounts,
the increase must be due to an
increased net rate of
uptake, reflecting a change in the physiology of the crab or a
change in the conditions in the environment, leading to a greater
availebility of,
in this case, Cs137 to the crab.
The latter
possibility is the more easily explained by the observations.
The same pattern of decrease in activity followed by a rise
is evident in the gut and liver of the crab,
the leaves of the
shruts, Scaevola and Messerschmidia, and the muscle of the field
rat, Rattus exulans, from Janet (Engebi) Island, which is also in
the northern part of Eniwetok Atoll.29 During the first 200 days
(May - November, 1954)
rainfall at Eniwetok
éveraged about 4
inches per month while for the following 150 days
(December -
April) the average monthly rainfall was about 0.3 inches (Fig.7).
Since individual variation in the level of activity 1s great
there would be little reason to accept the validity of the correlation were it not repeated in the plants and in rat
muscle,
which are also high in Cs137 content, (56% of the total activity
in the latter).
It appears likely, therefore, that the changes
in activity in the crab and rat muscle reflect some underlying
mechanism associated with rainfall which is responsible for
changes in the levels of activity in the plants.
DOE ARCHIVES
There could be one or several factors involved in the association with
rainfall
including,
for example,
such things
as
Zev