Payne S. Harris,* Steven L. Simon,’ and Shawki A. Ibrahim?

Abstract—Soonafter the Bravo nuclear test at Bikini Atoll in
the Marshall Islands on 1 March 1954, urine samples were
collected for analysis of excreted radioactivity from native
residents exposed to radioactive fallout on two atolls as well as
from U.S. military personnel on a third atoll. The earliest
acquired samples, obtained by the Los Alamos Scientific
Laboratory (LASL), were assayed for various radionuclides

Tue Bravo nuclear test on 1 March 1954 (local Pacific

time) resulted in early fallout on neighboringatolls in the
Marshall Islands lying primarily to the east of the test site
on Bikini Atoll (Fig. 1, Simon et al. 2010a). Exposure to
the fallout resulted in moderate to high radiation exposures
to small groups of native Marshallese and Americansliving
or staying on these nearby atolls (64 Marshallese on
Rongelap Island of Rongelap Atoll, 18 members of the
Rongelap community on Sifo Island, Ailinginae Atoll, 159
on Utrik Atoll, and 28 American military men on Rongerik

and provided the first known measurements of ‘I in urine

following exposure to fallout from a nuclear test. Over the
course of 1954, many additional samples were collected by the
LASL,as well as by the Atomic Energy Commission New York
Operations Office’s Health and Safety Laboratory and the
Naval Radiological Defense Laboratory. Collectively, the
groups sampled included Marshallese exposed on Rongelap
and Ailinginae Atolls, American military weather observers
temporarily resident on Rongerik Atoll, and sailors from the
Japanesefishing vessel, the Lucky Dragon. While the bioassay
measurement data and individual urine volumes have been
crucial to various attempts to assess intakes of radioactivity
and the related internal radiation doses among the Marshallese, those data have never been published in any peer-reviewed
journal, but have been restricted to agency memoranda,
laboratory reports, and summaries in some publications and
book chapters. Reconstructions of internal doses to Marshallese in 1954 and in later years have depended onthese data and,
hence, they have considerable historical importance as well as
importance to ongoing health risk projections for Marshallese.
This paper presents much of the original data on urine
volumes and radioactivity from the various assays of urine for

Atoll). In addition, but not considered here, were 23 sailors

on the Japanese fishing vessel, the Lucky Dragon.
The Marshallese exposed to Bravo fallout on the
atolls directly downwind were, collectively, one of the

first populations to be exposed to both high levels of
internal and external radiation from radioactive fallout,
the first population to provide information regarding
late-effects of acute to moderately-protracted environmental
exposures, and the first population to give information
about the health effects of exposure to radioiodines. In
companion papers, Bouville et al. (2010) and Simonetal.
(2010b) provide an assessment of external and internal

radionuclides, and compares estimates of *'I intakes madein

doses received by natives of all atolls of the Marshall
Islands from all tests conducted in the Marshall Islands,
including those highly exposed from Bravo fallout. The

1954, 1985, 1987, and 2008.
Health Phys. 99(2):217-232; 2010

Key words: excretion, urinary; fallout; °'I; Marshall Islands

estimated internal doses of Simon et al. (2010b) are

based, to a large degree, on the assay data reported here.
The primary pattern of high deposition from Bravo
as reported by numerousreferences (e.g., Conard 1975;
DNA 1979; Martin and Rowland 1982) was cigar-

* Santa Fe, NM (deceased, previously of Los Alamos Scientific

Laboratory); ‘ Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD;

shaped, 32—64 km wide, and extended eastward towards

* Department of Environmental and Radiological Health Sciences,

Utrik Atoll docated 570 km east of Bikini) with a slight

Colorado State University, Ft. Collins, CO.
For correspondence contact: Steven L. Simon, National Cancer
Institute, National Institutes of Health, 6120 Executive Blvd., Bethesda, MD 20892, or email at

northward curvature (also see Lessard et al. 1985). The

atolls of Rongelap, Rongerik, Ailinginaeall lay at intermediate distances to Utrik and had either permanent or
temporary resident populations at the time of the Bravo
test. Much lower depositions were also receivedat atolls

(Manuscript accepted 5 March 2010)

Copyright © 2010 Health Physics Society

DOI: 10.1097/HP.0b013e3 18 1dce50a4

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