Paper URINARY EXCRETION OF RADIONUCLIDES FROM MARSHALLESE EXPOSED TO FALLOUT FROM THE 1954 BRAVO NUCLEAR TEST Payne S. Harris,* Steven L. Simon,’ and Shawki A. Ibrahim? INTRODUCTION 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 ssimon@mail.nih.gov. 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) 0017-9078/10/0 Copyright © 2010 Health Physics Society DOI: 10.1097/HP.0b013e3 18 1dce50a4 217