99
their accidental exposureto fallout. During the
1959 survey 76 exposed persons, including their
Table 36
Residual GammaActivity, in counts/min/kg,
in Marshallese After Subtraction of K*’, Zn®, and Cs!*7
Age, yr
Rongelap exposed
Rongelap unexposed
Ailingnae
Utirik
1-15
> 15
36.1
21.4
17.2
37.9
35.0
43.0
8.8
11.7
with age or sex. No significant difference was
found between the Rongelap exposed and unex-
posed groups, which implies that no residual Zn**
activity remains in the Rongelap people from their
original exposure.
The 1959 mean body burden of Zn™ was 0,44
uC as compared to 0.36 uC in 1958. Thus Zn*”
body burdens do not seem to have reached a
steady-state equilibrium with the environment, as
is also the case with Cs'*’. Since the source of Zn*°
is fish, which continue to be a dietary staple, the
Zn* value can be expected to increasestill further.
The mean Utirik Zn* level in 1959 was about
one-third the Rongelap mean value.
Although Cs'*? and Zn** comprise the major
portion of gamma-emitting radionuclides present
in the Marshallese (aside from the naturally occurring K*°), residual gammaactivity is still present after subtraction of K*®, Zn**, and Cs'*’ con-
tributions from the total spectrum in each sub-
Ject (see Table 36). Analysis of the residual spectra
did not indicate any readily identifiable photopeaks in the short counting time employed (5 or
10 min). This short counting time, along with the
difficulties discussed earlier in exact calibration of
absolute activities, makes the identification of
minor photopeaksvery difficult. Most of the difficulties can be circumvented in futurefield trips by
the use of longer counting times, the use of an 8-in.
crystal, duplication of the geometry by use ofthe
same standardchair, and a moreprecise calibration of the phantom.
children, and 166 unexposed Rongelap people,
whoserved as a comparison population, were examined. In addition, groups of children at Utirik,
Majuro, and Kwajalein Atolls were examined as
controls for the growth and developmentstudies
on the exposed Rongelap children. The 1960 survey was brief, only the exposed people being
examined.
As a result of their exposure in 1954, many of
the Rongelap people had experienced early symp-
tomsrelated to the gastrointestinal tract and skin.
Later they developed a significant depression of
their peripheral blood elements commensurate
with the calculated dose of gammaradiation (175
r to 64 people and 69 r to 18 people), and beta
burnsof the skin along with spotty epilation. In
addition, radiochemicalanalyses of urine samples
showedthat they had acquired a low-level body
burden of radionuclides. Certain other findings
were possibly related to their radiation exposure,
such as loss in weight of several pounds in most of
the people during thefirst several monthsafter
exposure and suggestive evidence ofslight lag in
growth and developmentof the children based on
studies of height, weight, and bone development
(but inconclusive pending verification of exact
ages of someofthe children).
In spite of the depression of hemopoiesis, no
signs of radiation illness developed in the people
related to such depression, and no deaths occurred
that could be related to their radiation exposure.
Nospecific therapy was given. Recovery of the
peripheral blood elements, particularly lympho-
cytes and platelets, was very slow over the ensuing
years. The beta burns, which appeared about 2
weeks after exposure, were, for the most part,
superficial in nature and healed in several weeks,
with only a few lesions showing later persisting
changes. Specific therapy was not necessary in
most cases. The hair regrew normally, beginning
at 3 monthsafter exposure. The internally ab-
sorbed radionuclides caused no knownacuteeffects
and were excreted remarkably fast with barely
detectable activity being found a year or twolater.
On return of the people to Rongelap Island the
wid
Wf
3
burdensof cesium-137, zinc-65, and strontium-90.
The 5- and 6-year post-exposure surveys were
c )
Continuing annual medical surveys of the
people of Rongelap Island werecarried out in
March 1959 and March 1960, 5 and 6 years after
Cy
Summary and Conclusions
very low levels of radioactive contamination re-
maining there resulted in a rise in their body
aimed primarily at evaluating the general medical