56
Table 1.
Exposures of Marshallese Populations
Distance
Atoll
trom Bikini
No. of
Amount of
Heavy (snuow-like}
Maderate (mist-like)
peuple
Roneclap
Ailingae
~ LOO miles
~ 110 miles
67
19
Utirik
~ 300 miles
158
Estimated
fatlout
gamma dose
175 rad
69 rad
Noe vistble
14 rad
barium, and iodine. The significance of the radioiodine exposure was not
fully appreciated at that time. When thyroid abnormalities began to
appear, a re-evaluation of thyroid dose indicated an estimated dose of
335 rad to Rongelap adults and doses ranging from 700 to 1400 rad in the
children exposed at less than 10 years of age. Lower doses. were
calculated for the other populations. The higher doses in the children
were related to the smaller sizes of their thyroid glands. The largest
component was '"'f, but shorter-lived isotopes of iodine, particularly “1,
"3T) and "81, contributed more than half the dose.
The first indication of thyroid trouble was the finding of growth
retardation in a number of exposed Rongetap children, and later correlation with decreasing thyroid hormone levels indicated decreased function of the gland. Two boys developed frank myxedema. It was about
this time (1964) that thyroid nodules began appearing, particularly in the
exposed children. In subsequent years, the nodules continued to appear
in the Rongelap and Ailingnae group and, beginning about 1967, in the
Utirik groups. Table 2 shows the numbers of subjects who have had
thyroid nodules up to the present.
The Rongelap and Ailingnae people are seen to have greatly increased
numbers of nodules, both benign and malignant, and the Utirik group
also appears to have increased numbers compared with the unexposed
Table 2.)
Thyroid Nodules Appearing from 1964 to 1979.
Group
Total nodules
people.
children
Paradox
nodules
Dunn
develop:
without
of thyro
who hav
wU/m! 0
have two
The is
abnorma
Utink 11
followin,
to the a
radiation
Onar
the Mar
exposure
X irradia
the Mars
1337 and
rate than
The fir
exposure
which ra
neutrons
but also
which mz
Table 3.
.
Cancer?
Grov
Rongeiap and Ailingnae
(135-1150 rads)
36.0%:
4.7%
(31/86)
(4/86)
Utrrik
(30-95 rads)
9.55%
(15/158)
(3/158)
Lavaposed
6.6%
Utirik
(30-95 rads)
0.9%
(4/437)
Unexposed
(29/437)
au.
.
1.9%
n
The number ot cancer cases is tentative since final diagnoses on some recent cases are
pendiny.
Rongelap +
(138-1150 r.
* Some ofth:
and nodular: