5
EFFECTS OF FALLOUT RADIATION
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RONGELAP SUBJECT °79
TOTAL 66,974 CPM ABOVE BACKGOUND
(ANL. NO.4)
MAY [958
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GAMMA RAY ENERGY IN Mev
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Fig. +. Gamma-ray spectrographic data on Rongelap male (No. 79, exposed in 1954), comparing 3-vear body burden of y-ray isotopes (measured at Argonne National Laboratory)
after he had been living on an uncontaminatedisland oe body burden at 4 vears after he had
been living on Rongelap nearly 1 year. 67 AEBS.
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from Icniwetok to Rongelap.’ Lowlevels of Ba'4®-La'™® were also present on Rongelap, as indicated by the low levels of this isotope in the spectra of some of the
people measured on Rongelap. It should be noted that not all the subjects showed
a distinct peak at 1.6 Mev. or example, the spectrum shown in Fig. 5 has very
little net activity ubove 1.2 Mev. The presence of the large 1.6-\Mev peak in the
background, however, makes it difficult accurately to evaluate the K‘'° peak at
1.46 Mev, which shows up clearly in the 1957 spectrum.
The differences between the 1957 and 1958 body burdens of Cs? and Zn® reflect the different levels of these isotopes in the diet. It is not known whether they
have reached equilibrium with the increased amounts of these isotopes in their
present environment. Becuuse of the relatively short biological half-lives of Cs!"
und Zn*, little of the present levels can be attributed to the original activity which
was absorbed in 1954. Therefore most of the activity represents Cs"? and Zn®
ingested relatively recently.
KE. Late Errects
The acute effects of exposure of this population to fallout radiation have subsided. That the dose of whole-body y-radiation had been in the sublethal range was
® The absence of peaks except at 1.6 Mev and the fact that external procedures such as
washing down the decks and removing contaminated deck paint definitely lowered the background inside the room (from about 70,000 counts/min to about 25,000 counts/min total counts)
indicated that the contamination was outside the steel room.