Surveillance af Facilities and Sites nose Reassessment for Populations on Xongelap aridCtirik GK-ol-ol-52-3-(b Following Exposure co Fallout Project Title: 13. Publicatioris: None (a) 200 Word SummaV: Incidence of thyroid nodules, benign and malignant, in the exposed populations of Utirik and Rongelap have indicated critical differences in correspondence between nodule incidence and thyroid dose for the two populations. The estimated external dose received from the time fallout began to the time .of evacuation shows that the Rongelap population received an external.dose ( 17s rads) which was about thirteen times that for the Utirik population (14 rads), and the thyroid dose was about ten times larger, whereas the incidence of thyroid nodules in the two populations were not significantlydifferent. A preliminary study has indicated that the critical area of investigation that could shed light is the period during fallout and evacuation for both the islands. In addition, the fact that the Utirik population returned within 120 days following evacuation , whereas the Rongelap population retur~ed only after three years, requires that we look closely at the Utirik population in terns of a longer exposure period, both internal and external. Further studies would, therefore, have to concentrate on the re-examination of all available data in reports issued by various zgencies during that period, consultations with scientific personnel involved at that time, identifying the areas of uncertainty, and using appropriate computer programs to analyze the data. The end result will enable us to look for correlations between the incidence of thyroid nodules and the reassessed dose estimates. 15. Relationship to Other PYotects: (a) This study will help establish dose estimates from the time of the incident to the present, and will complement the aerial survey, for extenal radiation measureraents,over these islands, which is scheduled soon. Together they should present a reliable picture of doses received by the populations and also enable dose estimates to be projected into the future. (b) This study will be in close conjunction with the BNT Radiological Safety ?rogram in the Xarshall Islands and with related programs of the BNL Medical Department. Continued collaboration with the University of Washington, Laborator~ of Radiation Ecology, in the area of environmental radioactivity will be maintained. 16. Technical Progress in FY 1978: Preliminary literature search and consultations with Dr. C. A. Sondhaus, University of California, have been completed. This has resulted in defining areas of uncertainty in information and establishing the procedural steps that should be carried out towards elucidating this problem. Progress is being made (See Continuation Sheet) ——.. . ---.. -- -,.. ----___-.. . ... ------ ..... ..— ..... ..._ 6X- .— .- ihf