Surveillance Destse- Tile 13. 22 Facilizties and Sites Jose Reassessment for Posulacions sm Aongeiao and Vririx Following Exposure 29 Falsouc Gx-DL+OL-52-3-) Puolications i ee, oat me, None 14 Sccoce: (a) 200 Word Summary: ‘Ineidences of thyroid nodules, benizn and malig- mant, in the exposed sooulacions of Utirik and Rongelap have indicated critical differences in correspondence between nodule incidence and thyroid dose for che two populations. The estimated external dose received from the time iallout began to the time of evacuation shows that che Rongelap sooulacion vraeeived an external dose ( 175 rads) which was about tnirteen times ctnat for the Ucirik population (14 rads), and the thyroid dose was about ten tines larger, whereas the incidence of thyroid nodules in the two populations were mot sianficancly difference. A preliminary study nas indicaced that the critical area ci investigation chat could shed Ligne is the period during tfallouc and evacuation Zor botn she islands. In addition, the face that the Ucirik population returned within 120 davs following evacuactisn, whereas che Rongelap scoulation recurned only ater chree vears, requires that we Look closely at the Usirik a Longer exposure period, both internal and external. soosulacion in terms of Further scudies would, therefore, have to concentrate on the re-examination of all available data in reports issued by varicus agencies during that period, consultacions with scientific personnel iavelved at thac time, idencifying the areas of uncertaincy, and using appropriate computer orograms to analyze the data. The end vresule will enable us to look for correlations between the incidence of chyroid nodules and che reassessed dose estimates, 13. Relacionsaios 29 Other esatects: (a) This study will help establish dose escimates from the time of the incident to the present, and will complemenc the aerial susvey, fer extarnal radiation neasurements, ovar chese islands, wnich is scheduled soon. Together cney snould present a reliable sicture of doses received by the sopulations and also enadle dose astimates to be srojected inco the future. (b) This study will be in close conjunction wich the 3NL Radiological Satety Program in the Marshall Islands and with relatad programs of the 3NL Medical Department. Continued collaboracion with the University of Wasnington, Laboratory of Radiation Ecology, in the area of environmental radioactivity will be maintained. 16. Tecnnical Proeress in FV 1973: Preliminary Literature search and consultations with Dr. C. A. Sondhaus, University of California, nave been completed. This nas resulted in defining areas of uncertainty in information and establishing the procedural steps chac should be carried out cowarcs elucidating this problem. Zrogress is being nade (See Continuacion Shees) Gilet >] rm ee ee ee = ane