RADIOACTIVITY IN MAN
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in the Rongelap people as a result of living on their lightly contaminated island.
SUMMARY
Exposure to an acute fallout field results in three potential types
of radiation hazards to man: penetrating whole body gamma radia-
tion; superficial beta irradiation of the skin, mainly from contact
with fallout material on the exposed skin and toa lesser extent from
material on the ground; and internal absorption of radioactive
materials largely through ingestion and to a lesser extent from
inhalation. All these types of exposure occurred in the people
of RongelapIsland in the Pacific as a result of accidental fallout on
their atoll in 1954 following experimental detonation of a nuclear
device.
The most serious hazard associated with acute fallout comes
from penetrating gamma exposure which may result in acute
radiation syndromes. In the Marshallese people. the gamma dose
was sublethal but sufficient to result in (1) early nausea and
vomiting and (2) moderate depression of blood elements. There
were no clinical effects noted from the hemopoietic depression.
There was questionable effect on (a) metabolism as suggested
by temporaryweight loss; (b) growth and development in children
as suggested by slight lag in height and weight gain during the
first two years (being re-evaluated on the basis of better data) ;
(c) normal termination of pregnancy as represented by increased
incidence of nuscarriages and sullbirths in exposed women. No
other late effects have been noted.
Beta burns may be moderately incapacitating but the hazard
is not considered as serious as whole body gamma exposure. Simple
prophylactic measures will greatly reduce this hazard. The
Marshallese developed extensive beta burns, most of which were
superficial and healed rapidly. In some cases, there were deeper
burns with persisting changes (scarring, atrophy and pigment
aberrations) but with no evidence of chronic radiation dermatitis
or malignant change as yet.
The hazard from internal absorption is the least serious of the
three. andit is not likely that sufficient material could be internally