RESULTS AND ANALYSIS
ct exposure rate measuroments
at various
locations
in Micronesia.
Soil
samples
(Table
2)
from these areas were analyced for gamma-emitting radionuclides
ton, Laboratory for Radiation
Ecolozsy (3,
7) and by Brookhaven National Laboratory.
The
vertical distribution of fallout nuclides in the soil was
¢@ Sy vertical sampling profiles to a depth of 50 cn.
re
y concentrations of '?’Cs tended to decrease exponentially
boat
Are
réa
e*
with depth, with a "relaxation length" of about 5 cm?g-'.
r
cepositions of '47Cs were calculated by integration of the depth
é
tical sampling profiles.
o
ot
cistributicn determined from the v
»
™
w
Q
u“
rh
a
y
Exposure rates were then calculated by applying the coefficient
t 4.8 cm*g”} from EML-378 (8).
eo
These samples were
also analyred for “°K and for the uranium and thorium chains
sor wnaich the vertical profile data were averaged at each sample
location.
The respective exposure rate contributions were calcul-
ated from coefficients in HASL-195
tion was assumed to be 5.2 ywR/hr.
(9}.
The cosmic ray contribu-
(10).
Attempts were made to reconstruct ambient background exposure
rates
from soil analyses and the cosmic ray contribution at
fajurg,
Ponape and Truk.
+ and 5.
These locations are sufficiently distant
from tna test sites
Narshalls;
These cata are presented in Tables
(Bikini and Enawetak Atolls
53,
(> 500 km)
in the northern
that no evidence could be found to sugysest that they