“wind rose” data may have contributed to the weakness of this analysis. 4.4.2 External Radiation Doses to the Skin From External Fali-out Contamination Theoretical estimation of the external doses to the skin from electrons is not feasible, and must be inferred from the observed clinical signs based on current knowledge. When the radionuclides and theirdistribution and concentration on the skin are well-known, calculations may provide some estimates of the radiation dose to sensitive layers of the skin. In this case, the fall-out contained complicated mixtures of radionuclides that were | not uniformly distributed, and the distribution over the skin and the duration of exposure -afe not known. Doses to skin from photon sources deposited on Rongelap, were estimated to range from 3-20 Gy (300-2000 rad). This rough estimate was based on the assumption that the sources were distributed over a large, flat area of ground. Observations of skin erythema, ulceration and epilation on the scalp gave clear indication of high radiation doses of up to 35 Gy (3500 rad) to local areas of skin. Of course radiation dose to the skin was not uniformly deposited. A lack of correlation between skin effects and hematologic effects led early researchers to believe that skin contamination did not significantly contribute to total-body radiation dose. 4.43 Internal Radiation Doses As in the case of external skin contamination, an estimation of radionuclide intake is impossible, due to a lack of knowledge of the radionuclide concentration in the air, water, and food, particle sizes, chemical compositions, etc. A retrospective analysis of probable radionuclide intake was performed based on observed excretion of radionuclides in the urine. Pooled and individual urine samples were collected at various times starting at 15 days post-detonation, and the samples were analyzed for gross beta activity as well as radionuclide-specific activity. In addition, analyses of tissue samples from animals present at the contaminated sites (mostly pigs, chickens, and fish) were used to confirm the internal distributions of radionuclides when considered with the human urine excretion data. Estimated early body burdens of various radionuclides in the Rongelap population . are shown in Table 3. Analysis of radioactivity in tissue samples of the animals showed 21 mb gud éiéo