56 Table 1. Exposures of Marshallese Populations Distance Atoll trom Bikini No. of Amount of Heavy (snuow-like} Maderate (mist-like) peuple Roneclap Ailingae ~ LOO miles ~ 110 miles 67 19 Utirik ~ 300 miles 158 Estimated fatlout gamma dose 175 rad 69 rad Noe vistble 14 rad barium, and iodine. The significance of the radioiodine exposure was not fully appreciated at that time. When thyroid abnormalities began to appear, a re-evaluation of thyroid dose indicated an estimated dose of 335 rad to Rongelap adults and doses ranging from 700 to 1400 rad in the children exposed at less than 10 years of age. Lower doses. were calculated for the other populations. The higher doses in the children were related to the smaller sizes of their thyroid glands. The largest component was '"'f, but shorter-lived isotopes of iodine, particularly “1, "3T) and "81, contributed more than half the dose. The first indication of thyroid trouble was the finding of growth retardation in a number of exposed Rongetap children, and later correlation with decreasing thyroid hormone levels indicated decreased function of the gland. Two boys developed frank myxedema. It was about this time (1964) that thyroid nodules began appearing, particularly in the exposed children. In subsequent years, the nodules continued to appear in the Rongelap and Ailingnae group and, beginning about 1967, in the Utirik groups. Table 2 shows the numbers of subjects who have had thyroid nodules up to the present. The Rongelap and Ailingnae people are seen to have greatly increased numbers of nodules, both benign and malignant, and the Utirik group also appears to have increased numbers compared with the unexposed Table 2.) Thyroid Nodules Appearing from 1964 to 1979. Group Total nodules people. children Paradox nodules Dunn develop: without of thyro who hav wU/m! 0 have two The is abnorma Utink 11 followin, to the a radiation Onar the Mar exposure X irradia the Mars 1337 and rate than The fir exposure which ra neutrons but also which mz Table 3. . Cancer? Grov Rongeiap and Ailingnae (135-1150 rads) 36.0%: 4.7% (31/86) (4/86) Utrrik (30-95 rads) 9.55% (15/158) (3/158) Lavaposed 6.6% Utirik (30-95 rads) 0.9% (4/437) Unexposed (29/437) au. . 1.9% n The number ot cancer cases is tentative since final diagnoses on some recent cases are pendiny. Rongelap + (138-1150 r. * Some ofth: and nodular: