from the survey to be 7.2 x 1077 C kg~! ho! (0.28 R ho!) (0068). We recognize that soil analysis results exhibit orders of magnitude variations even when soil is taken from nearly the same spot (0C68). We assumed the exposure-rate surveys were correct for Utirik and we ignored this one soil activity result which would lead us to estimate very high thyroid doses. At Sifo Island, the fallout cloud passed by at 0.33 day post-detonation. The activity per unit area at Sifo, measured with one soil sample, was 1.2 x 109 Bq m2° (0.032 Ci m 2). At Eniwetak Island, the BRAVO cloud was estimated to have passed by at 0.67 day postdetonation and the measured sur face activity at that atime: based on two samples, was 1.2 x 10!0 + 7.8 x 109 Bq m2 (0.32 + 0.21 Ci m2). In Table 16 we tabulated activity per unit area and time post- detonation for Rongelap Island for nuclides contributing significantly to thy- roid dose. We based this tabulation on Bikini ash nuclide composition and we normalized the activity per unit area to the exposure-rate surveys made by the survey teams. In this table, the instantaneous surface activities during fall- out deposition reflect the buildup discussed earlier. We estimated the activity per unit area of selected nuclides at Utirik and Sifo Islands by using the ratio of the exposure rates at Rongelap and Utirik. The exposure-rate ratio for Rongelap and Sifo Islands was 3.0 to 1.0 and for Rongelap and Utirik Islands, 9.5 to 1.0 after the cessation of fallout. Although BRAVO debris was not highly soluble in water, calcium car- bonate and hydrated calcium oxide (the matrix in which BRAVO fallout was entrained) were both highly soluble in acid (Co72). Therefore, ingestion of BRAVO debris resulted in release of radioiodines and other nuclides trapped in the granules because of the acid environment of the stomach. The mass and volume of BRAVO fallout granules were insignificant relative to the normal amount of food eaten per meal, which was about 400 g for adults (Ev66). The mass of BRAVO fallout per square meter at Rongelap Island was 4.4 g and the volume of this mass was 1.9 cm’, about four tenths the volume of a teaspoon. These estimates at Utirik Island were 0.46 g m2 and 0.20 cm? m72. For Sifo Island it was 1.5 g m2 and 0.48 cm? m2. These mass and volume per unit area estimates were for the time at which all fallout was on the ground. They were based on the spe-~ cific activity and specific gravity of Bikini ash measured on April 23, 1954 (Ki56). The values for Utirik and Sifo Islands were estimated by ratio of their exposure rate to that at Rongelap Island after fallout cessation at the same time. The outside area used to prepare food for the midday or evening meals at Rongelap may have been within several square meters for a family (see Figure 13). shells. Boiling and frying were done over an open fire fueled by coconut Green breadfruit, fish, and nuts were roasted over a coconut-shell~ or husk~fueled fire, when the husk had turned to coals. Ground ovens, used for baking breadfruit, were normally protected with banana leaf coverings against dirt and dust (Na80). These outdoor preparation and cooking modes allowed significant amounts of BRAVO debris to be mixed with food. The amount of fallout dust ingested per meal would depend upon the amount that fell into utensils and plates during preparation and during consumption. Resuspension and subsequent deposition on food and preparation of food on - 48 -