than 95%. The number of food plants with a concentration three times the mean valueis less than 5% of the total. Therefore, the probability of a person finding his entire diet for 1, 5, 10, or 30 y from food crops with a concentration of three times the mean value is very small. Soil concentration data are also log-normally distributed with similar percentages accounted for by x, 2 x, and 3 X; concentrations in plants do, overall, reflect the concentrations in soil. The observed log-normal distribution of radionuclide concentrations in soils and plants at the atolls is consistent with most elemental distributions in nature. Also, the observation that three times the mean value includes more than 95% of the population distribution is consistent with other observations, several of which have recently been summarized by Cuddihy et al.” The 90c, concentration distributions in bone have been specifically addressed by Kulp and Schulert."8 . They found that 90sr from fallout was distributed log normally and that the 98th percentile value was 2.3 times the mean value. Maximum values observed for 905, in bone by Bennett were three times the mean; that is, most of the data fell below three times the mean. 27-29 These data also reflect the combined variability of the 905, concentration in food products and in dietary intake. The 13765 gamma-exposure data, which is listed in Refs. 6 and 11, show that the maximum exposure rate at an isolated point on the island is, for most islands, less than three times the mean value. In many cases, the maximum observed value is only two times the mean value. Because of the movement of people around their residence island, the variation of individual doses around the average dose is probably minimized and would not add much variability to the distribution of doses calculated for the ingestion pathway. In addition, we have not included in the external doses the reduction in external exposure that would occur from spreading crushed coral around the houses and shielding by the houses. Second, the dietary intake of local foods is a major source of input data that is somewhat uncertain and that could lead to higher average doses than presented here if the average intake were significantly greater than we have assumed. For example, if the current lifestyle for Rongelap, Utirik, and Bikini should change drastically with a total reliance on local foods, then the average doses would be higher than those listed here. This is a very unlikely occurrence because the people have a source of income and imported foods are now considered a staple and a necessity, not a luxury. The people will have access to outside goods and will trade with either the United States or other world 52