42 PRIVACY ACT MATERIAL REMOVED of the reacting antigen was under genetic control. Individuals with a dominant gene designated Ag' in single or double dose (genotypes 4g'/4g', ig! lg) were reactors [phenotype Ag(a+)| and those homozygous for the recessive allele Ag non- reactors [Ag(a —)|. The antigen or antigens that react with the antibodies present in the serum of the frequently transfused patient are serum low density 8-lipoproteins.'* A serum from a second patient / ), the New York antiserum, wasalso found to react with a low density f-lipoprotein. Preliminaryfamily studies indicated that reactors were homozygous or heterozygous for a second gene, while nonreactors were homozygousfor the alternate recessive allele. Immunologic, genetic, and population studies showed that the lipoproteins selected by the two antisera were antigenically distinct and controlled bydifferent genes.'* “Sera collected from the inhabitants of Rongelap Atoll in 1962 were tested with both the C.deB. fanti-Ag(a+)] and the New York antisera. The total results compared with those on several other populations are shownin Table 22. There is a much higher frequency of C.deB. antiserumreactors and a much lowerfrequency of New York antiserumreactors in the Rongelap population than in U.S. whites and Negroes. The reasons for these differences are not known, but maydepend on differences in past or present selective forces which affect the balance of the polymorphisms. Because of the lower frequency of New York anuserum reactors, the Rongelap population was useful for family studies. From these studies it was tentatively concluded that reactors with the New York antiserumwere either homozygousor heterazygous tor a dormant gene, and nonreactors were homozygous for its alternate allele.” Rodiochemical Analyses of the Urine. Determinations of body burdens of gamma emitting isotopes (principally Cs'’? and Zn"*) by wholebody gamma spectroscopy were not done during the past two surveys. Data in 1961, by that technique, indicated that the body burdens of Cs'*" were not significantly different from those of two vears before, and Zn levels had dropped by a factor of about 10. It was decided, therefore, to defer whole-body counts until the 1965 survey. Results of radiochemical urine analyses for Cs'*‘ and Sr” on 38 urine samples for 1963 and 27 samples for 1964 are presented in Tables 23 and 24. The data are divided into the following groups: S00 6029 exposed and unexposed of ages C15 and >15 years, living on Rongelap, Ebeye, and Utirik. Sr’ urine levels for 1963 and 1964 have not increased over the 1962 levels. In 1962, the mean Sr’" values from the individual adult 24-hr sam- ples were 12.45 pC/l or 114 pC/g Ca. From these values, on the basis of previous calculations," '” the body burden was estimated as 12.0 mpC for adults and 28.4 muC for children. On the same basis, the estimates for 1963 body burden levels of Sr*” are 11.3 mpC (adults) and 21.8 mpC (children); and for 1964, 10.7 muC (adults) and 23.1 mpC (children). As shown in Table 23, the levels of both Cs'*’ and Sr’® are lower for the people living on the uncontaminatedisland Ebeye at Kwajalein Atoll. Thus the return of the Rongelap people to their home island was reflected in annual increases to 1962 in estimated body burdens of Sr’ based on urinary excretion values. The annual estimates in myC for adults were as follows: 2.0 in 1958; 6.0 in 1959; 6.9 in 1961; 12.0 in 1962; 11.3 in 1963; and 10.7 in 1964. The present body burdens are about 5 to 6%(adults) to about 10% (children) of the maximum permissible concentration (MPC) of Sr" (200 muC) for non-industrial populations. It appears now that equilibrium with the environmental contamination of Sr’ yO has been reached in the people living on Rongelap Island, and the previously estimated equilibrium value of 23 myC will not be reached. No bone samples were obtained from autopsy material during the past two years for Sr®° analysis. Estimates of body burdens from previous analyses of bone samples had shown fairly good correlation with those obtained from urine analyses. In view of the paucity of the previous data on Cs'*’ urinarylevels, it is difficult to interpret the present levels in terms of body burden. However, the levels are generally less than the mean 1958 Cs'** urinary level of about 4 nC/I. Thisis in ac- cord with the finding by gamma spectrographic determinations that the whole-body burdens of Cs'** in 1961 had notincreased. Analyses of three coconut crabs for Sr®° and ‘Cs"" are shown in Table 25. Thoughthelevels of Sr*° (pC/g Ca) are lower than in the crabs ana- lyzed in 1962, they arestill sufficiently high to ne- cessitate continuation of the ban on their consump- tion by the people of Rongelap. It is interesting that the Cs'*’ levels are also quite high in these crabs. PRIVACY ACT MATERIAL REMOVED