as wall as
combine to make evaluations of local fallout contriou-
tions from U.
S.
Pacific tests indistinguishable from the
contributicens of the world-wide
Many small-scale radiological
*
>
fallout.
survevs were
.
°
conducted during
n
areas,
the greater distance of th
o
the 1950's and 1960's at or near the Pacific testing areas in
the northern Marshall
Islands;
nowever,
definitive evaluations
of the impacts of residual fallout radicactivity were not made
wn or suspected to be contaminated by tropo-
o.
J
oO
those island
"
(1-3).
ot]
until the 1970's
These evaluations were conducted on
spheric fallout from the tests at Bikini and Enewetak Atolls.
Environmental studies of peripheral areas
in the central Pacilic
were conducted on a small scale during the testing years
1958) by the University of Washington,
1979,
(1945-
and thereafter in 1975,
and 1980 by Brookhaven National Laboratory as well.
Those
studies vielded significant data on background radiation levels
in these areas, and form the basis for this report.
The Marshall Islands are all comprised of coral atolls or
partially drowned atolls formed by coral limestone accretions
on subsiding volcanic bases.
rilling studies at Enewetak
established that the limestone cap may exceed 1280 meters in
As
and thorium series
the contributions of the uranium
to the radiation environment in the Marshalls
i es are dominate
a.
st
ct
+
from th
ented by small contributions
ea]
rv
QO
&.
i
Oo
So
ye
Go
a
by cosmic rad
@
ot
he
<
those islands which are remotes
wa
External background radiation levels on
cb
are virtually nil
a result,
ct
(6).
fv
thickness
fron °°K,