eA population basis) in the Utirik group were in accord with the estimated lower eoses of radiation in these groups. 2. Skin Doses The skin exposure may have been several hundred to a few thousand rads. Symptoms of itching and burning of the skin were widespread in the Rongelap group. The lesser skin symptoms in the Ailingnae and Rongerik groups and their absence in the Utirik group wer- in conformicy with the reduced fallout exposure of these atolls. Also, the reduced number of “beta™ burns and epi- lation in the Ailingnae and Rongerik groups than in the Rongelap group and their absence in the Utirik group was in iine with the lesser fallcut exposure on these atolls. Though beta burns were numerous, particularly in the Roagelap group, the superficial nature of the lesions with rapid healing ane regrowth of hair was in conformity with the low penetrability of the beta radiaction. The lack of any evidence of chronic radiatior dermatitis or develop‘aent of skin cancer in later years is also indicative of this. 3. Internal Doses to Individual Organe or Tissues The widespread differences in energy spectra of the internally absorbed radionuclides made calculations of absorbed doses to the whole body and bone marrow extremely difficult. However, except for the thyroid, these absorbed doses are beliaved to have been small compared with the whole-body external exposure. Many uncertainties made the thyroid dose estimates difficult: first pooled samples, at 15 days post exposure, only the in the Rongelap aad Zongerik personnel showed 13ly, and the levels were low; the degree of urinary excre- tion of iodine at 15 days is uncertain; the amounts of potent short-lived io- dine isotopes present at the time of the fallout, particularly on the more distant atolls are unknown; the relative importance of absorption cf radionucides via ingestion of contaminated food and water versus inhalation is uncertain; and the thyroid dose is different .in adults and children because of the size of the thyroid gland, etc.* In spite of these difficulties it does not seem likely that the radiation doses to the thyroids would be too far removed from those calculated by James (19) since there should be a rough proportionality between the gamma dose estimates and the amount of radioiodines in the fallout, taking into account the time of arrival of the fallout; and, as pointed out above, there does not appear to be a great discrepuacy between the gamma dose estimates and the clinical findings. However, there could have been considerable variation among thyroid doses in different individuals depending on the amount of food and water consumed at the time of the fallout. As ,ointed out earlier, the two Rongelap boys who developed atrophy of the thyroid with ayxedema and other children probably received doses considerably higher than James' estimates for the 3J-year-old children be- use of the smaller size of their glands. Other factors which might hav. contributed to the higher doses in the small children were (a) that pldying in close contact with the contaminated ground increased their ingestion, etc., which is borne *See second footnote at beginning of this Appendix. -1W21-