« & Le ne eS le taanel le Bee l2 rth? 40 io «cs? MALE FEMALE --- 5-15 YRS +--5-I5 YRS — > I6YRS —— >16 YRS ft 8 6 GAMMA EMITTING RADIONUCLIDES IN RONGELA,’ POPULATION Trt? MARCH, I96I. 4 K rT 2 0 o 5 obo 8B l2 16 20 + vk myc/kg 8 lz 16 20+ muc/kg 14 16 22+ myc/kg lO 14 18 22+ mpc/kg MALE ---5-I5YRS — > IGYRS FEMALE ---5-I5 YRS — > f6YRS b- zné z 8 Sa 6z a 4 > _ oOo 2 2r L uw o ui = 2 oO lor— 1O cof? 14 18 22 26+ gm /kg 14 1B 22 26+ gm /kg RESIDUAL GAMMA ACTIVITY Br 6r dt 0 : 10 4 JI8 224+ IO mpc /kg 14 48 22 myc’ kg 4 12 20 28+ c/m/kg 4 le 20 28+ c/m/kg Figure 57. Frequency distribution of levels of radionuclides in various Marshallese groups. cally significant. Also, females tend to have values lower than those found in the corresponding male group (Figure 57). No significant difference between the Zn®concentrations in the exposed and unexposed groups could be determined. The percent variation within each group was approximately the same as in the case of Cs‘. Potassium-40 , - The mean K concentrations for the younger groups were consistently higher than those for the corresponding adult groups. The male adult group averaged 2.13 g/kg body weight and the female adult group 1.63. Total Residual GammaActivity Thetotal residual gammaactivity levels present after subtraction of the above four spectra are also shown in Table 17. The activity in cpm/kg has no absolute significance, butis of value in indicating, first, that there is someactivityleft, and, second, the natureofits distribution by groups. Members of the adult group have considerablyhigher levels of residual activity per unit body weight than do membersof the juvenile group. No significantdif- ferences were observed, however, on the basis of sex, or between the exposed and nonexposed groups. Cobalt-60 Radiochemical Analysis for Strontium-90 Analyses of the residual spectra obtained after subtraction of the three above-mentioned photopeaks revealed the presence of a fourth photopeak, Co*". The levels of Co®® were quite low (mean in the Rongelap inhabitants was 7.20.4 ppC/!: this represents a 14%increase over the 1959 value (6.3 wuC/l). This value is based on the results of =0,148 muC/kg), but were nevertheless readily detectible. No significant differences between the Co" levels in the exposed and unexposed groups, or on the basis of age or sex, were observed. The estimated 1961 Sr“* mean urinary excretion analysis of a pooled 20.8-liter sample collected from the adult population (see Table 18). This Sr*" urinary excretion expressed in terms of urinary calcium is 50.64+3.9 puC/g Ca. These values give wR es mere te roe nit 2h