SLIDE 59 Utirik summary. 6 use of the body-burden extrapolation equation leads us to the conclusion that Zn could have been the major contributor to the ingested activity during the first years post-rehabitation of Utirik Atoll. This was supported to some extent by a Japanese report (JCCRRER56) which indicated to us a rise in the photon count rate at the surface of various types of tuna retrieved from the Marshall Islands' fishing grounds from March to August 1954 (100-10,000 cpm). Fish with count rates greater than 100 cpm at the surface were discardedby the fishermen. Radiochemical techniques indicated the prominence of ~~Zn in the tuna's edible flesh. For committed effective dose equivajent, fhe impact of nuclides with a short mean residence time in the diet (~~Zn, ~“Co) was greater at Utirik because the population reinhabited within months of the BRAVO event. TRS tppact of nuclides with a long mean residence time in the diet ( Cs, Sr, Fe) was greater at Rongelap because of greater initial contamination. 1954-2004 UTIRIK PROTRACTED EXPOSURE SUMMARY Sv Adult Mean Nuclide ®O5 TCs ®7n Sr Sie External Total Bq 50 Year Intake 54,000 860,000 5,200,000 1,700 1,900,000 . Natural Background Subtracted - Committed Effective Dose Equivalent 0.00044 0.013 0.030 0.00010 0.00036 0.041 0.085