518
PROTRACTED EXPOSURE TO FALLOUT
Table 2 Average radionuclide burden and time since rehabitation for Uurtk adults
1.4xiG*
j.Gx.0%
2 5Fe
6.9x103( A)
90s,
“37a
239 py
2.8xi01(a
5
1 5x1 0*
(D)
9.6x103
4.4x103
2.3x104
3.7x103
9
27
19
6)
2.4x101 (a)
-
3.8xi0-
16
-
3976
1955
C
as
1038
173s
1957
1955
$72:
1970
1. 9xi0°
229x104
16
54x 1+
i. dx20%
(D)
4 .8x107
2.9x10-
13
2
Year
(Cc:
>. 8x103
6
(c
Ti4xid3
see
2
Time Pose
Rehabitation
Dave
3 inldica
5. BxiG3Ca
ic
5.0x10%
15
from Rongelap data,
«
2,2x10-
5
17
Adapted
(C:
1s
5, 8xi0ta,
6.1108
L.ixlo*
uc
5.9x1C-
-
1. 8x10!
4&.Ox10°
5.6108
A =
20 BL
La
Aduics (> 15a
Bodv
Number
Burder
of
_ §e
Individuals
Le
re
¢
, 2104
cD
18
9.2x107
1.4x103
2,5x103
12
65
2.oxd0°
2. x10-
1.5x1l02(A)
-
b.8x102
3.7 xi
1, 2x}02(a)
BL
x
22
48
1734
1959
F212
17a
9225
1979
Bob
1036
173
7213
8309
1978
1997
1959
1974
1977
36
126
9225
9935
1979
198:
-
6848
1973
text.
B= Measured at Argonne National Laboratory.
C = No femsles measured.
OD = Mumper of individuals noc recorded.
burdens for these nuclides in Rongelap residents
and the observed atoll-to-atoll ratios of adult
YELLOW WOOD and HICKORY expen-
were used in the calculation. Ratios were esti-
mentsin this series reached Rongelap. However,
several observations support the conclusion that
"Cs from this series was insignificant relative to
body burdens reached a maximum value. The
body burden of a similar population at Utrik
average body burden for “Zn, *Sr and '""Cs
mated for the period after the Rongelap adult
Rongelap-to-Utink ratio, 2.6+ 0.39. has been
relatively constant since 1958.
The initia! increase in 1958 in the Cs average body burden for Rongelap adults (see Fig.
2) was due to dietary intake of "’Cs and a small
intake of "Cs from the air and water due to
'37Cs trom the Castle series. First, the peak '°’Cs
occurred three vr after the initiating event (Cas-
tle BRAVO in 1954) while the 1965 peak "Cs
body burden at Rongelap followed the Hard-
tack series by seven yr. Secondly. the peak
lands during 1958. The subsequent drop in the
1959 "Cs body burden may have been due to
exposure rate on Rongelap which occurred during the Hardtack series in 1958 was about
10,000 times less than the peak exposure rate
following BRAVO. These facts suggest that
debns from the Hardtack series was not a
sion of the testing. The reason for an increasing
body-burden pattern during the mid 1960s. In
above-ground nuclear tests in the Marshall Is-
increased use of imported food and the conclu-
'57Cs body burden at Rongelap during the 1960s
was uncertain. Residual contamination from the
Hardtack weapons-testing program and sub-
sequent incorporation of "Cs into diet items
was one hypothesis.
The Hardtack Phase I series of tests was
conducted during 1958,-just before an increase
in the exposure rate at Rongelap Atoll (Un59).
Small amounts of fallout from the CACTUS,
IGtZbd
August VOR
3.$xi0/ Ca,
___
major factor influencing the Rongelap '’Cs
addition to Hardtack series fallout, the adult
average body-burden pattern would have
also been influenced by (1) worldwide fallout
fluctuations, (2) movement of adults in the
study population to a clean island oratoll for a
month’s visit with family or friends and (3) to
the initial success and subsequent failure
a
food subsidy program which began at Ronee ap
in 1958 (Co80b).
whole body counting results
8c,
55a;
Adult Femaies (>15a,
Body
Number
Burden
of
Ba
Individuals
Summary
Males {>15a*
Number
of
Individuals
Tuble 3)
Adult
Body
Burder
Bc