3. RADIATION EXPOSURE AND DOSE At Bikini exposure: (Table Atoll, external 1), and the from internal radiation radiation from beta, for .52 internal practically MeV; .66 dosage. MeV all from emitted gamma). dosage It also however, from the two kinds contaminated by contaminated (Appendix D). external Bone marrow, stems emanating radiations water or inhaled as gas or dust accounts dosage of soil food and The decay of cesium-137 (half-life accounts receives an 30 for years; mean practically additional from the decay of strontium-90 (half-life 29 years; mean beta, .93 MeV) (6). 7 all percent .196 MeV and | The calculation of the external and internal doses depends directly on the levels of soil and food contamination, and on assumptions regarding the Bikini diet (Table contamination 2, Figure in the atoll 3) (Appendix D). Although (Table 1) may differ greatly, the levels of in no case will they lead directly or indirectly to an acute or subacute reaction (Annex J in Reference 14}. The dangers of exposure, if any, would be registered as a late effect, namely, a small increase in the lifetime risk of cancer if sufficient is contaminated food eaten over an extended period and sufficient time elapses for the cancer to appear (15). 3.1 External Dosage Calculated the Eneu annual external (.012 rem) and for 1987, the earliest that resettlement might occur, dose person per Bikini (.16 (above rem) protection standard of .17 rem (Table 4) dose (world average) from background is natural within (6). the Federal for both radiation For comparison, the annual terrestrial ‘approximately 0.2 rem, and in the Marshall background) plus cosmic sources Islands it is less than is .03 rem (14, 16N, 17, 18). The Spontaneous annual decay soocnz2 ~ of dose declines cesium-137 progressively with time owing to the (half-life, i 30 years). Therefore, the