~~ 1297, 155£u, and 137ce were ¥SEY close to the hypothetical ratios ratios for r fission of estimated for thermonuclea U. 8. Estimation of Radioiodine Activity per Unit Area Based on Soil Activity for 1297, From the archival measurements, the iodine isotope activity was estimated per unit area of soil at the cessation of fallout at Rongelap (see Table,8). The enrichment of the iodine isotopes was assumed to be the same as for . The total radioiodine soil activity per unit area, based on 129 content of archival soils from Rongelap, exceeded the estimated total activity of all radionuclides per unit area by a factor of 10. The estimated total activity was based on four soil samples taken and measured for beta activity on March 8, 1954 (O0C68). The radioiodine soil activity per unit area, based on archival soils from Utirik, exceeded the estimated total soil activity per unit area by a factor of 7. Because these archival soil based estimates were so much greater than measured activity, the assumption could not be made that iodine isotopes mimicked the behavior of } Sy, and thus the usefulness of archival soil measure- ments was limited. The level of 129 in archival soil may be real, an artifact of the neutron activation technique, or the residue from other weapons tests occurring near the time of soil collection. Comparison of Bikini ash results to hypothetical results foxy 1297 (Table 7, column D/E) leads one to believe that some enrichment of '49T occurred but not to the extent indicated by our extrapolation of archival soil measurements (Table 7, column B/E). The level of activity of I in Bikini ash was based on direct measurements of !29Te and 1321 (1856). Table 8 Activity of Iodine Isotopes Based on Archival Soil Results Activity per Unit Iodine Area at Rongelap at 0.5 Day, 1297 aa 1.4x1074 1 «9x10? 1331 1347 2.0x10 2.0x104 Isotope I 135; Total Activity per Unit Area at Utirik at 1.5 Days, uci m728 5 .8x10 uci m+4 . 2.5x106 5.3x10° @Multiply by 3.7 x 104 to obtainBq m2. - 18 - a 9.0x1075 9.2x10? a 4.9x104 5.2x1076 . 2.5x10 9.8x103 9.3x104 ov vO - ; - . -