Table 2, External 137Cs gamma exposure-rate measurements in and around the houses ap village area of Rongelap Island. 137Cs, wR hr! Location | ~ Number of sites Mediana Meana Standard deviation In house 12 0.79 0.83 0.32 Outside house 22 1.5 17 0.98 General village sites 16 2.2 2.4 85 a Decay corrected to 1995. External Beta-Particle Exposure Airborne Radionuclide Conadentrations The unshielded beta contribution to the external dose was estimated for Enjebi Island at Enewetak Atoll in 1980 (Crase et al., 1982). The Airborne concentrations of 241Am are estimated from data resuspension experiments condu external gamma dose in estimating the whole-body dose. More recent studies at Bikini listed. average beta dose at 1-m height over open ground was 29% of the externa] gamma dose. The beta dose is delivered, for the most part, to the first centimeter of tissue, the so-called “shallow dose” and, therefore, should not be added to the Atoll using new, thinner thermoluminescent dosimeters (TLDs) indicate that the dose over open ground at 1-cm height is about three times that at 1-m height (Shingleton et al., 1987). Thus, the unshielded beta dose at l-cm on Rongelap Island could be equal to, or slightly greater than, the external pamma dose. For some portion of one day, people dosit or lie on the ground where the 1-cm exposure maybe relevant. However, for a significant part of the day, the eyes, upper body, and gonads are at 0.8 m or more in height above the ground surface. Moreover, it is important to realize that the beta dose to skin, for a number of reasons, will be significantly less than that determined from the unshielded TLDs placed over open ground. The walls and floors of the houses and the crushed coral customarily placed around houses and the village area absorb most of the beta radiation. Because people spend significant amount of their time in these areas, their exposure to beta particles is greatly reduced. In addition, any clothing, shoes, zories, Pandanus mats, or other coverings also greatly reduce exposure to beta radiation. 297+240Pu and developed in at Enewetak Atoll in February 1977, and at Bikini Atoll in Our study conducted on Bikini of 1978, provides a more comple than ourpreliminary studies on E set of data i Island at Enewetak Atoll in February of 1977. (Subsequent studies were conducted on Eneu Is Atoll.) The Bikini Island study extensive soil sampling and in- itu gamma spectroscopy to determine isotope ncentrations in soil and vegetation; (2) various ir-sampling rticle-size procedures to determine distribution, and radioactivit , and (3) micrometeorological techniques t@. determine aerosol fluxes. Four simultaneous experiments were conducted: (1) a characterization of the normal (background) suspended aerosofs and the contributions of sea spray off th@ windward beach leeward across the island, (2— a study of resuspension of radionuclides frpm a field purposely laid bare by bulldozers provide a worst-case condition, (3) a study of spension of radioactive particles by vehicul&r and foot traffic, and (4) a study of personaj inhalation exposure using small air samplersj carried by volunteers during daily routines. Less complete studies similar to those of (1) and (#) had been LC