2.) Soil Samples Some atolls, and islands within atolls, which may have to be evaluated as possible residence or agriculture sites do not yet have growing terrestrial subsistence food plants. A predictive methodology is therefore required to estimate the expected concentrations of radionuclides in local foods and the Subsequent radiological doses. This methodology is developed by determining “ the concentration ratio between the edible fruit and the soil (pCi/g fruit/pCi/g soil) for each radionuclide. These concentration ratios can then be multiplied by the average soil concentrations of an island with no existing crops to estimate radionuclide concentration in the foods. Soil sampling is, therefore, required for two purposes: 1) soil profiles to a depth of about 40 to 60 cm (this encompasses the active root zone of most food plants observed at the atolls) must be collected through the root zone of each sampled tree to develop additional concentration ratio data to confirm and expand the previously established concentration ratio data base. 2) soil profile samples to depths of 40-60 cm must be collected on islands that are to be evaluated for residence or agriculture. samples, The data developed from these in conjunction with the concentration ratio data base, will form the basis of the dose assessment for each island. Profiles may have to be collected on a 50 m grid in some areas to provide sufficient resolution to evaluate changes in soil concentration across an island; all profiles should be collected in the following increments: cm, and 25-40cm. O-5 cm, 5-10 cm, 10-15 cm, 15-25 A significant data base, developed from ongoing DOE programs, already exists for Enewetak Atoll but limited data are available for most other atolls. Supplemental data are necessary to expand the current information base to provide more reliable values for parameters in the predictive models. 30