MARSHALLESE EX PERIENCE
249
The Zn® body burden in the Marshallese in 1961 was 1.5 nc/kg, about
equal to that found in a few reactor workers at BNL [18], but considerably
higher than the mean value for the medical team (15 pe/kg). This latter
value is of doubtful significance, since it is not much higher than the precision of the instrument. The Zn® concentration in terms of body weight
in the Marshallese does not differ significantly between the exposed and
the unexposed groups, nor does it appear to differ on the basis of sex or
age (Fig. 7).
Potassium-40
The adult Marshallese male has an average of 2,12 g/kg body weight
as compared to the mean of 1, 72 for the medical team. This higher value
for the Marshallese probably reflects their well-developed musculature
and low body fat, as the K is proportional to the lean body mass. The K
‘values for Marshallese females are generally lower than those for the males,
1.52 - 1.71 g/kg body weight. The K values like those for Cs!37 are age-
dependent and, as previously mentioned, the ratio of Cs}57 /K* is aconstant
after approximately 20 years of age in both males and females [14].
Cobalt-60
A new and interesting finding of this study was the detection of the
presence of Co® in the Marshallese population, The mean value is fairly
uniform, about 11% of the Zn® level, but the spread in values in any one
group is again quite large (Fig. 7). There is a fairly good correlation be-
tween Zn® and Co® values. This induced activity had not been previously
detected in this population because its low level was masked bythe relatively large peaks of the other radionuclides in the relatively short counting
times employed.
lung from internally-deposited Sr,
D.
TREATMENT
CF
An effort was made at 52 d after the contaminating event in 1954 to
increase the excretion rate of the internally-deposited fission products in
seven Marshallese subjects. During a control period of 5 d, 24-h urine
samples were collected and analysed to establish a mean base-line excretion
oes se we
The residual y-activity in the spectra remaining after the subtraction
of the major components indicates that there are some residual radionuclides
not present in sufficient quantity to reveal themselves via their photopeaks
(Fig. 7). The adult groups had approximately the same level of residual
activity, while the juveniles had less than half of the adult mean level. This
difference may be the result of the error in geometry calibration of the
counter for children at the low energy end of the spectra. Undoubtedly part
of this residual activity in the low energy region results from bremsstrah-
OR
Residual y-Activity