35
tain gammaspectra on 227 people. Details of the
exposure and findings of these medical studies
have been reported.'~’
During the 1961 survey the portable shield was
used in conjunction with an improved detection
and data-recording apparatus. The gamma-ray
spectra of 110 people were obtained. Half the
people measured had been exposedto thefallout
in 1954; the other half were unexposed.
suming anddifficult. In 1957, several Rongelap
people were brought to Argonne National Laboratory, where it was demonstrated that their body
burdens of gammaemitters could be measured in
the whole-body counter. Cs'*’ and Zn* were
shownto be the prominent isotopes in the Marshallese at that time.
The Rongelappeople, originally evacuated to
another island in 1954, were returned to their
homeisland in July 1957. Since the island and the
indigenous food sourcesstill had a low level of persisting radionuclides, continued evaluation of the
body burdensin these people was of considerable
METHOD
Shielding was provided by a 21-ton room with
walls constructed of laminated '4-in.-thick steel
interest.
A portable whole-body counter was designed
and constructed at Brookhaven National Labo-
panels bolted together, which can be disassembled.
The inside dimensions of the room are 55 ft and
6 ft high. Figure 52 showsthe steel room (as set up
for the 1959 survey). In 1961 the room wasset up
in the cargo hold of the Roque (Figure 6). Along
with the steel room, an air-conditioned prefabri-
ratory and transported to the Marshall Islands,
whereit has since been employed duringthe annual medical surveys to ascertain the level ofinternally-deposited gamma-emitting isotopes. In
1958, 100 Marshallese people were counted, and
the procedure was repeated oneyearlater to ob-
cated wooden room 7x8 10 ft was set up to
house the pulse-height analyzer and otherelec-
Table 15
Frequencies (in Percent) of Gm Factors in Various Populations
(1m Factor
Population
No.
b
x
like
United States
White
Negro
Athabascan Indians ( Alaska)
Artic Village
Fort Yukon
Total
Africa
Yoruba
Fulani
Bashi
Pygmies
Rongelap Atoil
Surinam
Djuka Negroes
Javanese
Oyana Indians
Carib Indians
50.8
91.8
17.5
58
31
100.0
100.0
0
3.9
41.4
31.4
0
0
100.0 Av
1.8 Av
36.7 Av
O Av
364
109
Eskimos (Alaska)
Wainwright
Micronesia
303
-
98.1
97.5
3.0
6.0
0
277
50
100.0
20.0
0
35
35
37
120
100.0
100.0
100.0
100.0
100.0
100.0
94.6
100.0
0
0
0
0
100.0
94.3
35.1
100.0
149
100.0
97.3
0
43.6
35
20
15
19
100.0
100.0
100.0
100.0
100.0
100.0
86.7
79.0
0
15.0
26.7
52.6
62.9
50.0
0
0