Table 14 Serum [odine Serum Protein-Bound [odine Date Average, ug% Range. u2% No. samples Rongelap 6.2 4.4 - 9.2 12 1964 Medical team 4.9 2.5- 69 1965 Rongelap exposed 1959 1962 1963 1964 1965 1966 1966 Group Rongelap Rongelap Rangelap Rongelap unexposed Rongelap exposed Utirik exposed 8.6 8.1 7.1 7.6 7.0 6.1 11.8 Percent over 8 ue% 16 4.6 - 12.0 1.9 - 12.0 \4 29 64 66 2.0 - 10.2 1 36 4.1-11.9 3.9 - 10.7 3.1-11.8 6.9 — 28.7 19 - 3] 42 19 19 25 28 6 92 Serum Butanol-Extractable Iodine 1959 Rongelap 4.9 2.7 - 87 12 Serum Iodine Chromatography ig5y-L¥b4 1963-1966 1966 1964-1966 Group Total iodine, Av ug% Rongelap Rongelap Utirik Americans 6.98 7.40 18.10* 9.09 Todoprotein, Av ug% 2.22 2.80 9.20 0.80 T, 473, Av ne% No. samples 4.53 4.21 4.00 3.76 19 18 3 25 *One Utirik sample was quite high in total iodine (32.0 ug%)} suggesting contamination of this sample. The remaining 4 samples showed total iodine levels very nearly equal to the combined iodoprotein and thyroxine values. tion in PBI is a general phenomenonwhichaffects the entire population. The difference between PBI and BEIin 12 cases was 1.5 g%, which is somewhat greater than an average value of 0.6 pe% in the United States.*"*° This was suggestive evidence for the presence of iodoprotein in serum, andthe results obtained by column chromatography substantiate this, as an average iodoprotein level of 2.22 ug% was found. The average value for the amount of thyroxine iodine plus triiodothyronine iodine in these sera was 4.53 pg%. Five plasma samples from Utirik people assayed in 1966 showed an unusually high average of 9.2 ug% of iodoprotein. (See Table 14.) These data may be compared with results obtained on 25 normal North American controls residing temporarily in Washington, D.C., who showed an average serum iodoprotein level of 0.8 ug% and an average T, + 7; iodine level of 3.76 g%. Dietary lodine and Urinary Excretion of lodine. The supply of iodine in the Marshallese diet has generally been considered adequate in view ofthe large consumptionof seafood. Analysis of 24-hr urine samples from 28 people at the Boston Medical Laboratory in 1965 gave an average value of 105 pg iodine per day (range: 19.5 to 279), which is within the range of values found in an unselected population living in the Eastern United States.** A complete table of urinary iodine excretion data is presented in Appendix 4. Thyroid Uptake of Radioiodine. Uptake of radioiodine by the thyroid was tested in 1965 on 21 Marshallese (12 exposed and 9 comparison adults) with no known thyroid abnormalities. Studies with ‘971 were performed with a collimated 1!-in. NaI crystal 25 cm from the patient’s neck. The '*?I was milked daily from tellurium132 bound to a resin by elution with 0.1 Af NH,OH,andit was calibrated against a '*'Cs standard. The '**I (5 to 10 pCi) was administered by mouth before breakfast, and counts were ob- tained over the neck at 4, 1, 2,3, and 4 hr: a single 3-hr urine wasassayed for ‘**!. A predose count of the neck was performed, since a small amount of what was presumed to be **’Cs in-