Effects of fall-out radiation on Marshallese 279 to Rongelap. The background radiation resulting from residual contamination on the island presently averages about 0-04 mr/hr which represents a dose of only about 0-35 r/yr. 1000 Fo E Cs'52.. i § NET IN VIVO GAMMA-RAY 4 SPECTRA OF MARSHALLESE SUBJECT (NO.79)MALE, 4 AGE 44 P zn® ) iu z 'OOF marcH 1959 z F CHANNEL WIDTH ~ a < oO & ~ w” - - 4 MARCH 1957 CHANNEL WIDTH 50 kev Ps — q- — ~ “1 = Oo = 4 - oO 10 Figure 7. | 4 ior = ] 20 kev a uJ — > z = “2 1 .20 | .40 | .60 | 80 Mev I lO) | =3—r:«1.20—s.40s« 1:60 Gamma-ray spectroscopy of Rongelap man in March 1957 and March 1959. O-Bi-F 3, PRESENT STATUS It is apparent that the Rongelap people have recovered from the acute effects of their radiation exposure, and emphasis in the examinations is now directed toward possible late effects of irradiation, about which little is known in man. Noacute effects have been observed related to the internal absorption of radionuclides, and no late effects are expected, either from their initial intake or subsequent low levels acquired from living on the slightly contaminated island of Rongelap. However, the habitation of these people on the island affords the opportunity for a most valuable radiation ecological study. Since only small amountsof radioisotopes are necessary for detection with present sensitive measuring equipment, the various isotopes present on the island can be traced from the soil through the food and into the human being, where tissue and organ distributions, biological half-lives and excretion rates can be studied. ACKNOWLEDGMENTS The success of a mission of this type depends on the assistance of many individuals and organizations. ‘The author wishes to express his sincere appreciation to those who participated and others too numerous to mention