11
diation, but the caustic nature of the fallout may
have contributed.
The G.I. symptoms in the Rongelap people
consisted of anorexia and nausea (in about twothirds of them) and to a lesser extent of vomiting
and diarrhea (in one-tenth of them). Only a few
in the Ailingnae group complained of these symptoms, and no one in the Rongerik and Utirik
groups. The gamma exposureis thought to have
been sufficient to accountfor the G.I. symptoms,
but the ingested radioactive material (estimated
at about 3 mCi) may have contributed. The G.I.
symptoms were more prevalent in the Rongelap
children (see Table 4). These symptomslasted
only about two days and had largely disappeared
by the time the people arrived at Kwajaletn.
depression was greater in the children, particu-
larly those exposed at <5 years of age (see Table 5).
The changes are enumerated below in more detail.
Lymphopenia to about half the level of the com-
parison Marshallese population was evident when
the Rongelap people were first examined 3 days
after exposure. In children <5 years of age the
lymphocytes dropped to 25% of the level of the
comparison children but showeda slight rise dur-
Appendix 6 and graphically in Section III. C. The
showed a slight increase by one year.
The early
sequent years are presented in tabular form in
early findings are summarized here and thelater
ones in Section ITI. C.
Oneof the earliest findings in the Marshallese
indicative of significant exposure was lowering of
leukocyte and platelet levels in the peripheral
blood. This was most marked in the 64 people on
Rongelap who had received 175 rads and less so
in other groups receiving less exposure. The hemopoietic depression was roughly proportional to the
gamma dose of radiation received. Even in the
157 Uturik people who received only an estimated
Table 4
Nausea and Vomiting in Rongelap Group™
Incidence, %
Age at exposure, yr
No.
Nausea
Vomiting
<5
26
13
51
85
44
38
4
Table 5
Mean Blood Counts at Peak Depression
in Rongelap Group”?
Percent of control
Age <5
Neutrophils
7
CD
cc"
Lymphocytes
Platelets
tN
- radiation, since it was not considered likely that
the dose from internally absorbed radionuciides
contributedto it significantly. The hematological
hematological findings and the fAndings in sub-
b. Depression of Blood Elements.
cD
14 rads, it was possible to distinguishslight platelet
depression in the group as a whole. The smaller
groups on Ailingnae and Rongerik showed peripheral blood levels between those of the high and
low exposure groups. The hematological depression was thought to be due entirely to gamma
36
25
23
Age >5
64
35
34
ing the following weeks. The lymphocytelevels
Veutrophil levels showed considerable fluctuation
during the first month, possibly related to the
prevalence of beta burns of the skin during that
period. Neutrophil depression became evident by
3 to 6 weeks post exposure, the level dropping to
abouthalf the control level in adults andslightly
lower in children aged <5 (Table 5). Neutrophils
recovered more rapidly than lymphocytes and
reached near contro]levels by one year.
Early platelet counts showed less fluctuation
than other blood counts and decreased to about
30% of control levels by the fourth week. A spurt
of recovery to about 75% of control levels occurred
during the next few weeks, followed by slower
recovery with mean levels never exceeding 90 to
95% of control levels during the first vear. The
platelet count is probably the most sensitive index
of the severity of radiation exposure in the sublethal range.
;
Erythropotetic depression has not been a consistent
finding, and radiation effects on these cells have
not been demonstrable by peripherai blood counts.
Morphologtcal changes. During the period when
neutropenia was most severe, some people were
found to have peculiar monocytic leukocytes that
were thoughtto be large lymphocytes. These cells
were not found subsequently, although an occasional binucleated lymphocyte was seen.
¢. Clinical Findings. The developmentofsig-
nificant depression of peripheral blood leukocytes
and platelets during the first 6 weeks was cause for
considerable apprehension among the medical