5 similar to those of insular populations, we conclude that people from maritime cultures would exhibit similar and perhaps faster turnover rates of Pre because of the short "ecological half-life" (13) of this radionuclide in the marine environment. The highest >Re body burdens previously measured were in female natives at Bethel, Alaska, during 1966 (5). body burden of eighteen females was 1.1 pCi. year, The average During the same the average S56 body burden of females and males at Tokai- Mura, Japan, was 0.92 uci and0.63 pCi respectively (5). Ef the effective half-life of >? Fe in Richland, Washington, males and in Tokai-Mura males is comparable, by 1970 the latter group would be expected to havé body burdens of approximately O.1 pCi, four times lower than those measured in Rongelapese males. Iron-55 body burdens of females at Tokai-Mura might be expected to be comparable to those of males for reasons discussed earlier. All of the donors of the Rongelap study were subjected to external radiation during the accidental contamination of Rongelap Atoll in 1954, Because of the high levels of radioactivity at the Atoll, the Rongelap natives were moved to Majuro Atoll where they resided for three and one-half years. Following exposure in 1954, whole body counting and urinalysis disclosed measurable quantities of internally deposited fallout radionuclides. By 1957, however, the only radionuclides present in the Rongelapese in significantly measurable quantities were Coon, s (9). . 9 137 Cs and 90 Sr No 55 a analyses were performed at that time so body burdens