MEDICAL SURVEY OF MARSHALLESE TWO YEARS
AFTER EXPOSURE TO FALLOUT RADIATION
Introduction
Background
Following the experimental detonation of a nuclear device in the Marshall Islands
on March 1, 1954, inhabitants of four nearby islands were accidentally exposed to significant amounts of radioactive fallout material. The exposed personnel were evacuated to Kwajalein Naval Station where they were studied and cared for during a threemonth period. As a result of this study, it was found that the inhabitants of the two
most remote of these islands (28 Americans on Rongerik, and 157 Marshallese on
Utirik) had received only minimal effects from the fallout, and further examinations
were not considered necessary.
Accordingly, the American servicemen were re-
turned to duty and the Utirik people were returned to their homes. However, the
82 Marshallese who were on the two nearest islands (Rongelap and Ailingnae) showed
significant effects of exposure and required continued study at intervals. Since their
home islands were not considered safe at that time for habitation, they were moved to
an island in Majuro Atoll where homes were built for them and they have since been
comfortably established.
The results of the initial examinations have been reported (1-3).
Since this time,
follow-up studies on the Rongelap people at Majuro have been carried out and reported
at six months (4) and at one year postexposure (5). This report concerns the third
follow-up study carried out at Majuro in March 1956, two years postexposure.
Summary of Past Findings
The following is a brief summary of the past findings which can be found in detail
in references 1 to 5.
During the first 24 to 48 hours after exposure, about two-thirds of the Rongelap
group experienced anorexia and nausea and a few vomited and had diarrhea. At this
time many also experienced itching and burning of the skin and a few complained of
lachrymation and burning of the eyes. Following this, the people remained symptomfree until about two weeks after the accident, when skin lesions and loss of hair due
largely to beta irradiation of the skin developed. The effects of the irradiation can
best be summarized under three headings according to the mode of irradiation:
a) penetrating irradiation,
b) skin irradiation, and c) internal irradiation.
a) Penetrating Irradiation. The Rongelap people received an estimated whole-body
dose of 175 r and the Ailingnae people 69 r of gamma radiation. Depression of peripheral blood elements occurred as follows in the Rongelap people:
Lymphocytes fell promptly and by the third day were 55 percent of control values
(unirradiated Marshallese) in adults, and 25 percent in children.
The cells showed only
slight recovery by six months. At one year, there was further recovery but the cells
were still below control levels.
Neutrophiles fluctuated considerably during the first few weeks but fell gradually
to a low of about 50 percent of control values by the sixth week after exposure; recovery was slow. At six months counts were still below control levels, but by one year
they had returned to the level of the control population.