3
present at the time of exposure, who died 2 years
after the accident; (2) a 78-year-old man who
died, 3 years after exposure, of coronary heart disease complicating diabetes; and (3) a 36-year-old
man whodied of acute varicella, 4 years after exposure, who had received only 69 r, having been
on Ailingnaeat the timeof the fallout. There was
no apparentrelationship between any of these
deaths and radiation exposure, and mortality in
the exposed group did not appear to be greater
aq
than in the unexposed population.
It was difficult to evaluate theeffects on fertility.
However, a numberof apparently normal babies
were born during the 4-year period, and there has
been nodiscernible fall in birth rate. A slightly
higher numberof miscarriages occurred in the exposed women than in the unexposed group; this
will be further evaluated in the present report. No
opacities of the lens or other eye changes have
been found that could be related to radiation.
Studies on height, weight, and bone age seemed
to show a slight degree of retardation in growth
and developmentin the exposed children. However, the small numberof children involved, and
a later finding that exact ages of someof thechildren were in doubt, has resulted in a re-evaluation
of these data based on morereliable age determinations.
BETA IRRADIATION OF THE SKIN
It was impossible to get an accurate estimate of
the radiation dose to the skin. Beta burnsof the
skin and epilation appeared about 2 weeksafter
exposure, largely on-parts of the body not covered
by clothing, About 90% of the people had these
burns, and a smaller number developed spotty
epilation of the scalp. Most of the lesions were
superficial; they exhibited pigmentation and dry,
scaly desquamation, and were associated with
little pain. Rapid healing and repigmentation
followed. Some lesions were deeper, showed wet
desquamation, and were more painful. A few
burns became secondarily infected and had to be
treated with antibiotics. Repigmentation of the
lesions gradually took place in most instances, and
the skin appeared normal within a few weeks.
However, in about 15% of the people, deeper
lesions, particularly noted on the dorsum of the
feet, continued to show lack of repigmentation
with varying degrees of scarring and atrophy of
the skin. At 4 years the only residualeffects of beta
radiation of the skin were seen in 12 cases which
showed varying degrees of pigment aberrations,
scarring, and atrophyatthesite of the former
burns. Numeroushistopathological studies have
been made,'** and the changes found have been
consistent with radiation damage. At no time have
changes been observedeither grossly or microscopically indicative of malignant or premalignant
change. Spotty epilation on the heads was short
lived, regrowth of hair occurring about 3 months
after exposure and complete regrowth of normal
hair by six months. No further evidence of epilation has been seen.
An interesting observation was the appearance
of a bluish-brown pigmentation of the semilunar
areasof the fingernails and toenails in about 90%
of the people, beginning about 3 weeks after exposure. By 6 months, this pigmentation had largely
grown out with the nail and had disappeared in
most cases. The cause of this phenomenonhas not
been explained.
INTERNAL IRRADIATION
Radiochemical analyses of numerous urine
samples of the exposed population showedinternal
absorption of radioactive materials, probably
brought aboutlargely through eating and drinking contaminated food and water andto a lesser
extent through inhalation. Duringthefirst few
days when the body levels were at their highest,
the maximum permissible concentrations were approached orslightly exceeded only in the case of
strontium-89 andtheisotopes of iodine. The concentrations were believed to be too low toresult in
anyserious effects. Bodylevels fell rapidly, so that
by 2 and 3 years post exposure, they were far below the accepted maximum permissible level; by 6
monthsactivity in the urine was barely detectable.
The return of the Rongelapese to their home
island (which after careful survey was considered
safe for habitation, despite a persisting low level of
radioactive contamination) wasreflected in a rise
in their body burdens and increased urinary excretion of certain radionuclides. Beginning in
1957, gamma spectroscopy by use of a low-level
counting chamber was addedto the techniques of
radiochemical analysis. This, along with radiochemical] analysis of urine samples, showed an increase in body burdens of cesium-137 by factors of
up to 100 and ofstrontium-90 by a factor of 10 to
20; and someincreasealso in zinc-65, since the re-