tain gammaspectra on 227 people. Details ofthe 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 suming and difficult. In 1957, several Rongelap a a people were brought to Argonne National Labo- ratory, where it was demonstrated that their body burdens of gamma emitters could be measured in the whole-body counter. Cs'*’ and Zn*° were shown to be the prominent isotopes in the Marshallese at that time. The Rongelap people, originally evacuated to in 1954; the other half were unexposed. 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 burdens in these people was of considerable METHOD Shielding was provided by a 21-ton room with walls constructed of laminated '4-in.-thick steel panels bolted together, which can be disassembled. Theinside dimensions of the room are 5X5 ft and 6 ft high. Figure 52 showsthe steel room (as set up for the 1959 survey). In 1961 the room wasset up interest. A portable whole-body counter was designed and constructed at Brookhaven National Laboratory and transported to the Marshall Islands, where it has since been employed during the annual medical surveys to ascertain the level of internally-deposited gamma-emitting isotopes. In 1958, 100 Marshallese people were counted, and the procedure was repeated one yearlater to ob- in the cargo hold of the Reque (Figure 6). Along with the steel room,an air-conditioned prefabri- cated wooden room 7x8 x10 ft was set up to house the pulse-height analyzer and other elec- Table 15 Frequencies (in Percent) of Gm Factors in Various Populations Gm Factor Population No. United States White Negro Athabascan Indians (Alaska) Artic Village Fort Yukon Total 303 364 98.1 x 91.8 17.5 97.5 like 0 3.0 27.7 58 100.0 0 41.4 0 51 100.0 3.9 31.4 0 100.0 Av 1.8 Av 109 Eskimos(Alaska) Wainwright 50.8 b 36.7 Av 50 100.0 20.0 35 35 37 100.0 100.0 100.0 100.0 100.0 94.6 0 0 0 0 100.0 1-9 100.0 97.3 0 43.6 Djuka Negroes 35 100.0 100.0 0 62.9 Javanese Oyana Indians Carib Indians 20 15 19 100.0 100.0 100.0 100.0 86.7 79.0 15.0 26.7 52.6 50.0 0 0 Africa Yoruba Fulani Bashi Pygmies 120 Micronesia RongelapAtoll Surinam oom by wi a “ pe VGant ‘tie3 100.0 100.0 6.0 Q 0 100.0 94.3 35.1 Od 4 Le MY; I TE TCEEIGEIT RR RRSree SE EO AS Re IOR SRE LE Ng mp rw eae mT oe ye + : ae Av fee tae en ae A Aene ee cmoreeae ae ” “39