André Bouville,* Harold L. Beck,’ and Steven L. Simon*
Castle series, all of which were high yield. The measurement data used for those estimates of exposure were
collected by two methods: (1) stationary, ground-level
continuous reading Geiger-Miiller type instruments with
paper strip chart recording mechanisms, and (2) aerial
surveys using fixed wing aircraft that carried scintillometer instruments. Mostof the atolls of the Marshall
Islands, including all that had populations of signifi-

Abstract—Annual doses from external irradiation resulting
from exposure to fallout from the 65 atmospheric nuclear
weaponstests conducted in the Marshall Islands at Bikini and
Enewetak between 1946 and 1958 have been estimated for the
first time for Marshallese living on all inhabited atolls. All tests
that deposited fallout on any of the 23 inhabited atolls or
separate reef islands have been considered. The methodology
used to estimate the radiation doses at the inhabited atolls is
based on test- and location-specific radiation survey data,

deposition density estimates of "’Cs, and fallout times-of-

cant size, were monitored in the aerial radiological

arrival provided in a companion paper (Becketal.), combined
with information on the radionuclide composition of the fallout
at various times after each test. These estimates of doses from
external irradiation have been combined with corresponding
estimates of doses from internal irradiation, given in a companion paper (Simonetal.), to assess the cancer risks among
the Marshallese population (Landet al.) resulting from exposure to radiation from the nuclear weaponstests.
Health Phys. 99(2):143-156; 2010

surveys in 1954 (Breslin and Cassidy 1955). The range
of estimated cumulative exposures from the Castle
series reported by Breslin and Cassidy (1955) covered
approximately five orders of magnitude, similar to the

range of '*’Cs concentrations measured in the environ-

ment of the Marshall Islands by the Nationwide
Radiological Study conducted approximately 40 y

Key words: '’Cs; dose, external; fallout; Marshall Islands

later (Simon and Graham 1994, 1997). The USAEC-

placed instrument on Rongerik Atoll was responsible
for alerting the U.S. military weather observers on
Rongerik to high levels of early fallout, leading to
their evacuation and to the evacuation of Marshallese
from Rongelap, Ailinginae, and Utrik following the

DEsPITE NUMEROUSefforts to monitor the Marshall Islands
for radioactivity during the United States Pacific nuclear
testing program andafterwards, there has beenrelatively
little effort towards estimating radiation doses to all
Marshallese exposedto the fallout from the testing. The
United States Atomic Energy Commission (USAEC)
issued a report on radiological surveys following Operation Ivy of 1952 (Eisenbud 1953) and Operation Castle
of 1954 (Breslin and Cassidy 1955). The latter report
estimated cumulative exposures from the tests of the

test Bravo in 1954 (Eisenbud 1987; Simon 2000).

Other than atoll-specific values for the external
exposure (reported in Roentgens or R) published in the
USAECreports (Eisenbud 1953; Breslin and Cassidy

1955), and later estimates of external dose by Lessard et

al. (1985) for Rongelap and Utrik, few, if any, external

dose estimates have been reported for Marshallese. One
significant source of information on nuclear testing in the
Marshall Islands, a special issue of Health Physics
(Simon and Vetter 1997), was largely concerned with

* Division of Cancer Epidemiology and Genetics, National Can-

land contamination, resettlement issues, and assessments

cer Institute, National Institutes of Health, Bethesda, MD 20892;
* New York, NY 10014 (retired from U.S. DOE).
For correspondence contact: Steven L. Simon, National Cancer
Institute, National Institutes of Health, 6120 Executive Blvd., Bethesda, MD 20892, or email at

of doses received decades after nuclear tests were conducted in the Marshall Islands. Until the publication of
this paper, no systematic effort had been made to

(Manuscript accepted 5 March 2010)

estimate the annual doses from external irradiation,
received from 1948 to 1970, from all tests at all

Copyright © 2010 Health Physics Society

inhabited atolls.

DOI: 10.1097/HP.0b013e3 18 1de521d

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