wa
os
northern atoll reef.
The island chain is quite long and
narrow and has only sparse vegetation.
Several ‘tests of nuclear devices were conducted in the
near vicinity of this island complex, and thus the extremes
in radiation leveis typical of blast areas were found here.
A survey using the portable meters was made along a route
down the middle of the complex.
These measurements ranged
from 5 to 20 ur/hr on Aomen, 20 to 330 ur/hr on Lomilik,
to 40 ur/hr on troij, and 3 to 7 ur/hr on the causeways.
10
Except for the higher values on Lomilik, these exposure
rates were typical of weathered, sandy soils capable of only
low retention of radioactive materials.
The hot spots on
mney
Lomilik were depressed areas with clay-like soil.
A soil sample was taken from the area of greatest
activity.
The soil analysis indicated that ®°Cco was responsible for more than 3/4 of the total exposure rate, with
*85ch and lesser amounts of ~°?™ph and *°’¢cs contributing
almost all the remainder.
155
Traces
of 1°° Rh,
*°.Rh,
14446,
Eu, and ***Am, and thus *°°Pu were also detected (see
Figure 12).
A 1964 sample from Iroij indicated that at that
time ©°Cco contributed about 75% of the total exposure rate,
122 sb about
8%,
*87 63
about
9%,
and +°2Mph the remainder,
in
substantial agreement with the 1967 data for Lomilik.
Many pieces of fairly radicactive metal scrap were
found throughout this area.
Although most of the time this
contamination was due to °°Cc several samples exhibited only
unidentified 240 keV gamma-ray activity.