-3-
METHODS
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Pe-
Solely
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lacking.
Radioactivity of common substances and organisms at Eniwe-
tok Atoll was evaluated in two ways,
first by concentrated study
involving many organisms collected frequently at one island,
Belle, and second, by less intensive study at several islands
sround the atoll in order to elucidate the geographical distri-
bution of the activity.
Belle Island (Fig. 1) was the
uno (Banildefonse)
wl
major collecting and observation
site, except for rats, for which
it was Janet Island.
thig40th,+)
Collections
were made on April 15, 1954 at
Belle before the Nectar test,
almost daily for the week after,
and at increasing intervals later.
The second aspect of the study,
at several islands,
involved pre-
Nectar collections in April and
May, and nine to ten post-Nectar
collections, usually expedited
by helicopter, at intervals in-
Lf bette Copembogey
ede
atin OS
we
a
Po
7
_
at which time six islands, Henry,
Leroy, Alice, Olive, Vera, and
The remain-
other studies.
Cer.
E Rawheamiles
wn
ee memey come
vse
ing two islands, Janet and Elmer,
were sampled at approximately
the same times in connection with
{
|esea
z
.
epheroy (Rigili)
nigase
creasing from one to nine months,
Bruce were visited.
aereentids:
:
i
edged
aS
*
a
7
Fig. 1. Map of Eniwetok
Atoll
Survey meter readings were taken frequently at Belle,
but m
only about half of the visits to other islands.
The Juno meter
was used for high (Table 2) levels of activity and the Geiger
counter (Nuclear, MX-5) for low levels.
Several spots were
usually monitored with the instrument one inch from the ground
and with the shield both open and closed.
Similar readings
three feet from the ground were taken less frequently and
not
included.
are
For the distributional study on the various islands a handful of island soil from the top inch, intertidal beach sand, a
few milliliters of sea water, algae, and three sea cucumbers
were taken.
Periodic trips by M-boat around the periphery of the
lagoon, a mile or two centrally from the islands, served
for
sampling sea water, plankton, and pelagic fish by rod and reel.
Plankton tows usually lasted from 15 to 30 minutes at from one to
two knots per hour using two 1/2-meter nets, fine (No.20 of 173
mesh/inch) and coarse (No.6 of 74 mesh/inch) towed simultaneously
from either side of the M-boat.
Large jellyfish.
if present were
removed and the samples preserved by adding formalin to make 5%.
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Ri.