z ENEU EONJEBI 1OMELAN BOKANTUAK A total of 23 devices of both fission and thermonuclear types were detonated during 1946, 1954, 1956, and 1958. The islands of Bikini Atoll received fallout from these tests to varying degrees. The leargesc islands, Bikini and Enev, located at the Eastern end of the atoll, were generally upwind of the detonation sites and thus received lesser amounts of fallout debris than some of the other islands, The relative Locations of the islands of Bikini Atoll and the test sites are shown in Figure | with the number of tests indicated ROKERE x o in the circle. the atoll, (1) Figure 1. BIKINI ATOLL Survey teams have revisited the atoll between testing periods and AEROKOJENEMAN - COMPLEX in 1946. #tnce testing was concluded to obtain samples of marine life, land plants and aniwala, soil, water and to spot-check the external radiation levels within = Radiological Survey and Monitoring Activities An assessment of che impact of test activities on the environment at Bikini Atoll was begun ahortiy after the first two detonations were conducted In 1964, a survey team visit to Bikini Atoll produced a sizeable quantity of data on the radionuclide content of foods (marine and terrestrial) that would be available to a returning population. In December 1966, the USAEC in responding to a request from the Secretary of the U.S. Department of the In- terior, agreed to make a determination on whether Bikini and its lagoon were Instrumentation To provide cross-checks on measurements and flexibility sufficient that detailed data could be obtained for certain Locations with rapid coverage of other areas, several types of semiportable and portable instruments were used. The Health and Safety Laboratory (HASL) of the USAEC provided two semiportable instruments, a high pressure fonization chamber and an X-ray spectrometer, plus a small portable scintillation counter survey meter and thermoluminescent dosimeters (TLD's). The U.S. Naval Radiological Defense Laboratory (USNRDL) BOKDROLUL Sp LUKOJ JELETE SY NAUT. MILES The survey team spent 16 days at the atoll in April-May 1967. Except for Adrikon, @ very small island in the Southwest corner of the atoll, all fourteen dselands and tha two complexes of islands joined by man-made causeways were surveyed. Seven days were spent with studies on Bikini Island. BOKBATA Planning for a major survey effort by tha staff of the USABC Division of Biology and Medicine (now the Division of Biomedical and Environmental Research, DBER) began early in 1967. The emphasis was on delineation of the external radiation fields particularly on islands and at Locations of past and future habitation and to obtaining more measurements on all islands including the smaller islands near test locations. Dr. Edward Held, who at that cish was at the University of Washington, Laboratory of Radiation Ecology, Seattle, Washington, was appointed survey team leader. Team membership included personnal from USAEC, USAEC contractors, U,S, Trust Territory, and the U.S. Naval Radiological Defense Laboratory. Four native workers were added to the team in Myafjalein. DyADRIKAN 1967 Survey @Q BOKAETOKTOK @ OROKEN ' ENIDAIK safe for continued habitation and whether the Bikinians could have harard-free use of the resources of the atoll and ite adjacent water areas. Subsequently, it wae determined that the available survey data were not yet complete and that another team visit was needed to conduct a more extensive survey of external radiation levels in Bikini Atoll. Also needed, for projections into the future, was a determination of which radionuclides contributed to this radiation field.