tal
In contrast,
tne Caroline
1)
Islands,
immediately west of the
are comprised of high
volcanic islands
with fringing coral reefs, as well as coral atolls and islands.
The high island soils contain *?7Th and 773U and their daughters.
Tae additional contributions of gamma emitters among these
racionuclidces result in background exposure rates
(at 1 meter
above the ground) which are nearly a factor of two higher than
those similarly measured on the coral
atolls
(Table 1}.
Con-
tributions of stratospheric and tropospheric fallout are, of -
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rn
oO
WN
superimposed cn these natural background radiation sources.
rd
course,
Data for this study were obtained during three field trip years
(1975,
1972 and 1980).
The
first of the
field trips was
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he
ct
rn
fo
avs
aw
fo
°
th
conducted jointly with the University of Washington, Laboratory
n Ecology (LRE), which was responsible for determining
background concentrations of fallout radionuclides in soil and
adoratory
~
(BNL)
was
Brookhaven National
tasked with the measurement of external
cund radiation.
Subsequent field trip activities focused
4
Ch
Va
w
uo
t
in terrestrial and marine biota (7).
om external radiation measurements only.
The measuriment sites were generally restricted to the District
T he Trust Territory
Lisnmed region whichn encomnassed
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ct
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ral
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teeir accessibility via commercial airline.
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_—
Centers of the Trust Territory of the Pacific Islands because or