3.
RADIATION EXPOSURE AND DOSE
At
Bikini
exposure:
(Table
Atoll,
external
1),
and
the
from
internal
radiation
radiation
from
beta,
for
.52
internal
practically
MeV;
.66
dosage.
MeV
all
from
emitted
gamma).
dosage
It
also
however,
from
the
two
kinds
contaminated
by contaminated
(Appendix D).
external
Bone marrow,
stems
emanating
radiations
water or inhaled as gas or dust
accounts
dosage
of
soil
food and
The decay of cesium-137
(half-life
accounts
receives
an
30
for
years;
mean
practically
additional
from the decay of strontium-90 (half-life 29 years; mean beta,
.93 MeV) (6).
7
all
percent
.196 MeV and
|
The calculation of the external and internal doses depends directly on
the levels of soil and food contamination, and on assumptions regarding the
Bikini
diet
(Table
contamination
2,
Figure
in the atoll
3)
(Appendix
D).
Although
(Table 1) may differ greatly,
the levels of
in no
case will
they lead directly or indirectly to an acute or subacute reaction (Annex J
in Reference 14}.
The dangers of exposure, if any, would be registered as
a late effect, namely, a small
increase in the lifetime risk of cancer if
sufficient
is
contaminated
food
eaten
over
an
extended
period
and
sufficient time elapses for the cancer to appear (15).
3.1
External Dosage
Calculated
the
Eneu
annual
external
(.012
rem)
and
for 1987,
the earliest that resettlement might occur,
dose
person
per
Bikini
(.16
(above
rem)
protection standard of .17 rem (Table 4)
dose
(world
average)
from
background
is
natural
within
(6).
the
Federal
for
both
radiation
For comparison, the annual
terrestrial
‘approximately 0.2 rem, and in the Marshall
background)
plus
cosmic
sources
Islands it is less than
is
.03 rem
(14, 16N, 17, 18).
The
Spontaneous
annual
decay
soocnz2 ~
of
dose
declines
cesium-137
progressively with time owing to the
(half-life,
i
30
years).
Therefore,
the