410363 BNL20767 MARSHALL ISLANDS RADIOLCGICAL FOLLOWUP * Noa. Groechouse and TLF, McCraw deaith Physics aad Safety Division, sroosnavea National Luvoratory, Upton, New York 11973 and Division of Operational Safety, U.S, Energy Research and Development Administration, Washington, D.C, Abstract 20545 : In August, !243, President Johnson announced that the people of Cixini Atoll would be aole to return co their homeland, Thereafter, similar approval was given for che return of the peoples of Enewetak. These two regicns, which comprised the Pacific Nuclear [esting Areas from 1946 to 1958, will probably be repooulated ‘+ sSe crizinal inhabicants and their families vichin the nexe vear., As part of its coneinnin: Tet ps D> Lit, fc: idcure she sialic sea.ta wae 2 allic la comnmection wien che nucilcar pregrams uncer .c3 sponsurship, IRDA (formerly AEC) has concracted 3rookhaven National Laboratory toa establish radiological safety and environmental monitoring programs for the returning 3ikini and Enewetak peoples. These programs are described in the following paper. They are designed co define the external radiacion environment, assess radiation doses from internal emitters in the human food chain, make long range predictions of tocil doses and dose commitments to individuals and to each population group, and to suggest actions which vill minimize doses via the more significant pathways. Introduction The U.S. nuclear testing programs of che 1940s and 1950s had significane local environmental impacts on the coral atolls of Bikini and Enewetak in the Marshall Islands. The high level close-in fallour made these acolls uninhabitable for many years. Fallouc from the a@RAVO event, which took place art Bikini in 1954, was inadvertently deposited on the nearby atolls of Rongelap, Rongerik and Utirik. In all, some thirteen atolls in the northern “Marshalls were probably affecred to a greacer or lesser extent by fallouc from these nuclear tests. Of these, however, the mose significane long term radiological impacr was on the cest atolls, Bikini and Enewetak, and on Rongelap atoll. In '°S7, Rongelap was reoccupied Sv ins original -nhabitanes who had been evacuated cwo days ifter BRAVO. uring the past several vears, definitive o.ans have Deen made to repatriate the original inhaoitants cf 3ikini and Enewerak Atolls, and their families. Ie is hoped that their return can take place soon. In order to identify radiological problems from residual radioactivity in the environmenr, and to provide a data base for dose predictions applicable to the returning populace, ERDA (and its predecessor, the AEC), has sponsored many radiological surveys in the Marshall L[slands. These surveys began during test operations and have been conducted periodically up to the present time. Results of the surveys have been published in numerous reports and scientific journals, References 1 chrough 12 are published reports of AEC/ERDA supported surveys of these atolls, References 13 through 29 are a portion of the published reports on work with collected environmental samples supported by AEC/ERDA. Evaluation of survey results for 3ikini Atoll, che consideration of predicted exposures dompared with applicable radiation standards, and the acknowledgement of the many benefits to the people if they could return, led to the decision to clean up and rehabilitace that atoll, The Deparcment of Defense, Department of the Interior (DOI), and AEC (now ERDA) parcicipated in a joint effort of clean up and rehabilitaVicind Atoll starting ia Cthoalcmy lot. Tllaa op vas vompienss cq che fall cor chat yeus, Agrie fon cultura: rehabilitation and housing construction is being conducted by DOI, The decision to return the Enewetakese co their atoll led to a comprehensive survey conducted at Enewetak in 1972-1973. (19) 4 regional survey planned for 1976 will provide baseline radiological daca for future dose assessments throughout nearly all of the northern Marshall [Islands which may have been affected by the cescing program. Environmental evaluations at Rongelap and Utirik Atolls have been undertaken Psoreay in association with ERDA'’s medical evaluations program there over the past 20 years. * From all of these earlier surveys, it became apparent that periodic environmental monitoring and dose assessments must be made for Bikini, Enewetak, Rongelap and perhaps other atolls in che northern Marshalls to maintain a currence radiological data base and to provide currence information on individual and popuLation doses. This followup monitoring is being performed by Brookhaven National Laboratory at the request of the Division of Operational Safety, U.S. Energy Research and Developmenc Administration. BEST COPYAVAILABLE *Research carried out at Brookhaven National Laboratory under the auspices of the U. S$, Energy Research and Developmenc Administration, .3y acceptance of this article, the publisher and/or recipient acknowledges che U.S. Government's rigne co retain a nonexclusive, royalty-iree license in and to any “copyright covering this paper.