10 rads. Calculation of the dosage from radioiodines unfortunately had to be based on a single, pooled urine sample from Rongelap people collected 15 days post exposure. Harris?? at Los Alamos had reported a low level of 1311 in this sample and had calculated a one-day thyroid content of 11.2 »Ci based on the assumption of 0.1% urinary excretian of the maximum thyroid burden onthe 15th day. 20 James calculated doses for absorption from both inhalation and ingestion. He noted thar the shorterlived isotopes of iodine delivered 2 to 3 times the estimated dose delivered by 1311 alone. The importance of these shorter-lived isotopes in pro- ducing thyroid effects in the Marshallese will be referred to in Section IV. The dose to the thyroid of a Rongelap adult (including gamma) was cal- culated as about 335 rads (220 to 450 rads) and to that of a 3-year-old Rongelap child as 700 to 1400 rads. (The spread is due to uncertaintiesin esti- mating dose from absorption of radioiodines by inhalation versus ingestion.) With the assumption that the ratio of whole-body gammadoses to thyroid doses was the same as for the Rongelap people, James’ calculations were used to estimare thyroid doses in the Ailingnae and Utirik groups; the results were 135 rads for the Ailingnae adults Thyroid wt (yg) and 27 rads for the Utirik adults. The children’s thyroid doses were based on the weight of the gland at various ages (Figure 3).°3 By using a linear relationship between the thyroid size and the dose calculated by James, the doses to indi- vidual children were taken from regression lines drawn for the three exposed populations (Figure 4); these are given in Section IV. In retrospect, the estimated average dose of 1050 rads to the thyroids of young children appears to be low,at least for two boys who developed atrophy and myxedema. Figure 3. Weights of human thyroids in New York City. (From Mocuizuxi eT av.*8) re—_—_—_r_—_—_,_TT a The calculated doses are obviously rough estimates. The incompatability of the observed effects with the calculated doses based on 1311 must be related partly to the greater dose effect of shortlived iodine isotopes (see Appendix 9C). B. ACUTE EFFECTS A = 4 1. Effects of Whoile-Body Exposure Thyroid dose (rads) a. Early Symptoms. 7 “ys 4 4 L —_ L. | : 0 Vink L 9 1 a i L 5 hen i. 1 Lt 4 L 10 i i eens ‘a 15 ok deere 20 Figure 4. Thyroid dose versus age for children in exposed Marshailese groups. Duringthefirst two days, before evacuation, symptomsrelated to the skin and the gastrointestinal tract were noted in a large number of Rongelap people, in a lesser number among the groups exposed on Ailingnae and Rongerik, and in none of the Utirik group. The severity of the symptoms was correlated with the amount of fallout and the radiation dose. Skin symptoms (itching and burningof areas not covered by clothing) were noted in about one-fourth of the Rongelap peopie, and a few complained of irritation ofthe eyes and lachrymation. These symptoms were thoughtto be related to betairra-