152
Health Physics
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pt
Annual Doseto Adults (mGy)
_|
tt
tt
—*— Rongelap Island
community
—¥— Utrik community
“—
Kwajalein(S)
|. _|
August 2010, Volume 99, Number 2
received by the U.S. military weather observers who
were stationed there and evacuated within 2 d of the
detonation. The Rongerik dose is based on only a few
survey meter measurements madeafter the evacuation by
a survey team but agrees very well with reported external
exposure measured by film badges worn by the personnel
(35-98 R) (Sharp and Chapman 1957), particularly
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10°
107
1 0°
(1930 to 1958), are presented in Table 6 for the Majuro
FL
.
+
y
|
t
1948 1950
1
al
{
1955
t
|—__
1960
—
}
1
4
—
1965
1970
Year of exposure
Fig. 5. Estimated annual doses, in mGy, to adults of four
population groups.
Table 4. Estimates of external doses (mGy) received by adults
from the Bravo test, the entire Castle (1954) test series, and from
all tests (dose estimates rounded to two significant digits).
Atoll or population
group
Ailinginae*
Ailinglaplap
Ailuk
Arno
Aur
Bikini community”
Ebon
Enewetak community*
Jaluit
Kwajalein
Lae
Lib Island
Likiep
Majuro
Maloelap
Mejit Island
Mili
considering the considerable uncertainty in both sets of
measurements and the fact that some of the military
personnel were indoorsat least part of the time.
Whole-body absorbed doses (mGy) from external
irradiation, cumulated over the time period from 1948
through 1970, for representative persons by birth year
Namorik
Namu
Rongelap control group*
Rongelap Island community*
Rongerik®
Ujae
Utrik community*
Wotho
Wotje
Castle
series
All tests
460
0.37
470
5.3
470
6.9
2.3
3.3
1.1
0.71
2.1
9.3
77
5.0
4.8
14
10
9.9
14
5.3
25
15
7.8
22
10
Bravo
37
1.1
1.0
1.6
0.7
25
2.2
5.1
27
1.8
0.70
0.73
8.4
1,600
940
1.0
110
4.3
17
37
4.8
11
37
59
6.6
12
39
8.7
11
47
9.8
12
49
4.4
9.0
17
1,600
—
6.4
130
13
30
5.5
11
22
1,600
—
8.6
130
23
31
6.4
7.0
“Includes doses received while relocated (see Table 3 in Simon et al.
2010a).
> Includes doses while on Kwajalein and Kili (see Table 3 in Simonetal.
2010a).
“Includes doses while on Majuro and on Rongelap Island.
“Dose to U.S. military personnel on Rongerik prior to evacuation (see
Table 3 in Simonet al. 2010a).
residents, the Kwajalein residents, the Utrik community,
and the Rongelap Island community. As noted, doses for
Utrik and Rongelap Island communities account for
relocations. For a given population, the cumulative doses
are greater for persons who were young at the beginning
of the testing period.
The radionuclides that contributed most to the dose
rate from external irradiation vary according to the time
elapsed since the detonation. These contributions can
readily be derived from the tables prepared by Hicks
(1984), as the relative exposure rates are providedforall
radionuclides for a range of times after detonation. As an
example, the changing proportions of the external dose
rate contributed by some of the most important contributing radionuclides to external exposure are shown in
Fig. 6 for the Bravo test and an assumedrelative degree
of fractionation, R/V, of 0.5. In Fig. 6, '’Te is the most
important radionuclide within a few hoursafter thetest,
but is replaced successively by '°Ba-'°La, Zr, and
finally by '*’Cs. Expressed in percentage of total exposure (averaged over a range of degrees of fractionation),
'?Te-'*T accounts for about 25-30%, '*°Ba-'°La about
20%, 1 + 131 + '*I about 15-20%, and *Zr-”’Nb +
'Zr-'Nb about 10-15%. The exact percentages at any
atoll and following any particular test also depend on
fractionation with greater relative contributions from
Zr-Nb isotopes for larger R/V values. Although '°’Cs
and '°Ru contribute little to the total integral dose
from TOA to 1970, they contribute almost all the
annual dose after 5 y.
All together, the deposition densities of 63 of the
radionuclides listed in Simonetal. (2010a, Table 4) have
been estimated at each inhabited atoll or reef island
following each of the 20 tests. These radionuclides
combined contribute more than 95% of the external dose.
The proportions of the total exposure contributed from
the individual radionuclides shownin Fig. 6 are actually