__ roncantrations at Bikini and Eneu Islands: the mean from the aerial survey, collected for the mean and median of the O- to 10-cm depth from all profiles att i4land, and the distributed mean, which is calculated by dividing each safand into six regions, determining the median 137¢s concentration for the profiles jn each region, and then calculating the mean value of the medians prom the six regions. For all other islands, the mean from the aerial survey ang the mean and median from the soil profile data are given. as shown in Figs. concantrations is inc ramEents . Thus, 3 to 10, lognormal; the aerial the distribution of soil radionuclide this distribution is observed for all depth data are compared more appropriately to the median and distributed means than to the mean value, which over-emphasizes the raw high 137Cs soil concentrations observed in the lognormal distribution of sol | For cadionuclide concentrations at the Atoll] (Robison et al., 1981c). gxample, the average 137¢s soil concentration at Bikini Island from the aerial survey 45 45 pCi/g; the median value from the terrestrial soil profile data is 5Y pul/g and the distributed mean is 60 pCi/g, both in good agreement with the For Eneu Island, the aerial survey result is 3.4 pCi/g, and the madian and distributed mean are 3.6 and 3.8 pCi/g, respectively, for 273 aprial survey. sol! profiles. for most other islands, the aerial survey gives higher !37Cs soil concentrations than does the terrestrial soil profile survey. There are two peanons that could account for this observation. First, the number of soil profiles collected at islands other than Bikini and Eneu are limited. This is bacause, aS We mentioned in the Introduction, the time available at the other The distribution of the telands was short and dictated by the aerial survey. raw soil profiles taken at each island during the NMIRS is critical; soil radtonuc lide concentrations are generally higher in the interior than at the periphery of an island. However, in many cases, the field team could not reach the interior of the islands because of the very dense vegetation and, A, a took the profiles nearer the periphery of the islands (see Appendix Elys. Al to A-14, for sample locations). In contrast, for Bikini and Eneu islands, We have a major, continuing program that provides a constant source at samples. Second, each soil profile represents a very small area of the ys and and just a few kilograms of soil. The aerial survey detector system, ay the other hand, views large areas of the island and tons of soil. error tively 5000321 integrates the activity over a large surface areas. It For small