Reljable assessments of actual doses must be determined through personnel monitoring. External radiation dosimeters do not appear to be a practical means of personnel monitoring for individual external dose measurements, although certain individuals within given populations may be relied upon to wear them. A "lifestyle model" which includes estimates of occupancy factors for various locations in a given atoll has been coupled with environmental monitoring data to estimate average external radiation doses to individuals, This model will be revised as needed so that it closely approximates the actual lifestyle of the people. The more important internal pathway can be monitored directly by conventional techniques of bioassay and whole body counting of individuals. A portable shadew shield whole body counter has been constructed and mounted in a shipboard tralier for use in the Marshall Islands. It is capable of quantitative detection of very small quantities of certain radionuclides in the body such as 137cs and 890, the primary environmental gamma emitters at Bikini, Enewetak and Rongelap Atolls. The system clearly identifies individuals in the Rongelap population who are not following the recommended dietary restrictions on eating coconut crabs from certain locations. (42,43) Body burdens of 905r/90y, 259,240py and 24lam are estimated by the radiochemical anaivsis of urine samples. Urine sample collections and whole body counting will be performed every one to two years at Bikini and Enewetak Atolls when the people return, and every two to three years at Rongelap Atoll until the results warrant less frequent measurement intervals. Summa Marshall Islands Radiological Followup has consisted of intensive environmental studies at Bikini, Enewetak, and Rongelap Atolls to gather radiological data on the external radiation environmene and on radioactivity in food chains. Radiation and radioactivity levels in these atolls are being reduced with time. These changes are monitored in annual or biannual environmental surveys. Updated information is used to make conservative estimates of population doses and dose commitments. When people have returned, actual internal doses to individuals are determined for whole body counting and bioassay data. These results are combined with environmental data on the external radiation environment to complete the total dose assessment picture. References 1. Dunning, G. M., "Radioactive Contamination of Certain Areas in the Pacific Ocean from Nuclear Tests, A Summary of the Data from the Radiological Surveys and Medical Examinations", USAEC Report, August, 1957, 2. Held, E. E., "Gamma Dose Rates at Rongelap Atoll, 1954-1963", USAEC Report, UWFL-91, May 1965. 3. Donaldson, L. R., et al. "Bikini-Eniwetok Studies, 1964, Part I and LI", University of Washington, Laboratory of Radiation Biology, UWFL-93, September 15, 1966. 4. Beck, H. L., Bennett, 8B. G. and McCraw, T. F., “External Radiation Levels on Bikini Atoll'} May 1967, USAEC Report, HASL-190, December 1967. 5. Bennett, B. G. and Beck, H. L., "External Radiation on Bikini Atoll", Nature 223: 925-928 , 1969. 6. Held, E. £., "Radiological Resurvey of Animals, Soils and Ground Water at Bikini Atoll, 1969-1970", University of Washington, College of Fisheries, NVO-269-8 (Rev. 1), February 1971. 7. Smith, A. E. and Moore, W. E., Report of Radiological Clean up of Bikini Atoll, Office of Dose Assessment and Systems Analysis", Western Environmental Research Laboratory, Environmental Protection Agency, SWRHL-lllr, January 1972. 8. McCraw, T. F. and Lynch, 0. D. T. Jr., "Exposure Rate Reduction on Bikini Island Due to Concrete Dwellings, USAEC Report, WASH-1273, June 1973. ie McCraw, T. F., "Levels of Environmental Radioactivity in Bikini Atoll", USAEC Report, WASH-1289, 1974, 10, Enewetak Radiological Survey, Volumes I, II and III, USAEC Nevada Operations Office, Report NVO-140, October 1973, ll. Lynch, 0. D. T. Jv., MeCraw, T. F., Nelson, V. A., and Moore, W. E., "Radiological Resurvey of Food, Soil, Air and Ground Water at Bikini Atoll, 1972", USERDA Report, ERDA-34, February 1975, 12. Gudiksen, P. H., and Robison, W. L., "Preliminary External Dose Estimates for Future Bikini Atoll Inhabitants, Lawrence Livermre Laboratory Report, Preliminary UCRL-51879, August 1975, 13, Palumbo, R. F. and Lowman, F. G., "The Occurrence of Antimony-125, Europium-155, Iron=55 and Other Radionuclides in Rongelap Atoll Soil", USAEC Report UWFL-56, April 7, 1958. 14, Lowman, F. G., "Marine Biological Investigations at the Eniwetok Test Site", from Disposal of Radioactive Wastes, International Atomic Energy Agency, Vienna, 1960, 15. Walker, R. B., Held, E. E. and Gessel, S$. P., "Radiocesium in Plants Grown on Rongelap Atoll Soils, Rec, Advan, Bot. 2: 1363-1367, 1961. 16. Cole, D. W., Gessel, S. P. and Held, E. E., “Tension Lysimeter Studies of Ion and Moisture Movement in Glacial Till and Coral Atoll Soils’) Soil Sci. Soc. Am. Proc. 25: 321-325, 1961. 17, Lowman, F. G. and Palumbo, R. F., "Occurrence of Bismuth~207 at Eniwetok Atoll", Nature 193: 796-797, 1962, 18, Chakravarti, D. and Held, E. E., "Chemical and Radiochemical Composition of the Rongelapese Diet", J. Food Sci. 28: 221-228, 1963. 19, Kenady, R. M., "The Soils of Rongelap Atoll, Marshall Islands", University of Washington Press, Corvallis, 1962. 20. Held, E. E., "Qualitative Distribution of Radionuclides at Rongelap Atoll", Amer. Inst. Biol, Sci., Reinhold Publ. Co., New York, 1963, pp. 167-169.