22 ing on their homeisland was small, it was decided to allow the people to return. Rongelap people are interrelated and represent a remarkably homogeneous population. Theylive under the same environmental,sociological, and CONCLUDING REMARKS The increasingly widespread uses of radioac- tive sources in research and industry increase the possibility of exposure of people to various forms of ionizing radiation. Therefore, greater knowledge of such effects on humanbeings is badly needed. Considerable research is being carried out on ef- fects of radiation on animals, but there are obvious economic conditions and are likely to remain together as a groupindefinitely. As contrasted with the Japanese,the dose ofgammaradiation received is reasonably well established. Also in contrast to the Japanese, these people have been subjected to only minimal psychic and no physical trauma. In view of these facts, continued medicalsurveys of the Marshallese people are anticipated on an annual basis. limitations in extrapolating such data to the human species. Human experimentation,particu- larly with regard to whole-body radiationeffects, is limited to therapeutic use of radiation in diseased people. Though such data are useful, they must be evaluated with caution. The most valuable information about humanradiation effects, therefore, has comefrom people irradiated from atomic bombs such as the Japanese people of Hiroshima and Nagasaki and the Marshallese, from a few isolated laboratory accidents, and from individuals having ingested radium. The group of irradiated Marshallese people offers a most valuable source of data on humanbeings who have sustained injury from all the possible modes ofex- posure-penetrating radiation,beta radiationof the skin, and internal absorption of radioactive materials. The acute.and subacuteeffects of these different forms of exposure have been well documented andfor the most part have subsided. Even though,as pointed out, the radioactive contamination of Rongelap Island is considered perfectly safe for human habitation, the levels of activity are higher than those found in other inhabited locations in the world. The habitation of these people on the island will afford most valuable ecological radiation data on human beings. Since only smail amounts of isotopes are necessary for tracer studies, the various radioisotopes present can be traced from the soil, through the food chain, and into the human being, where the tissue and organ distribution, biological half-lives, and excretion rates can be studied. Such investigations will be done by the use of whole-body gammaspectroscopy of the people and of sample materials, and by radiochemical analyses ofsoil, food, and humanexcreta. Several factors favorably influence these studies on the Marshallese. The exposed and unexposed Summary Results are reported of a medical survey on the Marshallese people exposed to radioactive fallout three years previously. Examinations werecarried out at Majuro in the Marshall Islands on 82 people from Rongelap who had been exposed to the heaviest fallout and on a comparison population of unexposed Rongelap people matchedfor age and sex. A Navy LST was used for the second phase of the examinations to examine 144 people of Uurik Island who received the least fallout. The survey showed thatall the irradiated Marshallese people were makingsatisfactory recovery from their radiation exposure. Thefollowingis a summary ofthe findings on the Rongelap people. ACUTE AND SUBACUTE EFFECTS Penetrating radiation Diseases. In general the incidenceofdisease,in- fectious and noninfectious, was about the samein the exposed as in the unexposed group. No symptoms were present that could be related to radiation effects. Several interesting findings were noted in both the irradiated and unirradiated groups: the incidence of congenital anomalies was high; peptic ulcer and psychic disturbances wererare; the incidence of dental caries was very high; and intestinal parasitism was widespread. Nutrition. Nutrition appeared to be as good in the exposed as in the unexposed groups. Growth and development. In the exposed children from about 4 through 9 years of age there was a slight lag in bone maturation (based on x-ray studies of the left wrist), and these children were

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