28 units for populations at large) based on analysis of a small sample of bones from the Rongelap man who died in April 1958, if this sample is representative. Since children may havelevels higher than those of adults bya factor of 10, their values maybe as high as about '4 of the stated maximum permissible concentration (30 to 40 puC Sr”). However, this estimate is based on bones of American children and. since consumption of milk by the Marshallese children is practically nil compared with that by American children, this extra- polation may not be valid. Based on urine analy- ses for Sr*" excretion, the average 1958 level was 3.42 ppC Sr’’/l urine, or about half the level found during the first month post-exposure (6.2 puC Sr°’/l urine). Itis not known whether the body burdens of Sr*" in the Rongelap people have yet attained equilibrium with their environment, and this point will be carefully followed in future studies. Although the rapid rise of the Ebeye people’s values toward those of the other Rongelapresi- dents suggests that equilibrium values have been approached, the daily excretion rates indicate that equilibrium with the environmental values cannot be assumed. In anyevent, the increase in activity between the 1957 and 1958 surveys andthesimilarity of the results for the exposed and unexposed groupsindicate that mostof the radioactivity seen is the result, not of the initial contamination, but of more recent ingestion of food containing radionuclides. It is known from other studies**-** that the soil and food plants on Rongelap contain low levels of fallout products. Eating of land crabs has been proscribed becauseoftheir relatively high Sr“° content. Among other foods the pandanus fruit shows the highest Sr*’ content, but this fruit represents a relatively small part of the diet. Other plant foods such as coconuts and breadfruit have relatively low levels of Sr*® activity. These plants also contain lowlevels of Cs'**. Calculations of the radiation dose rates on the basis of existing data are subject to much uncer- tainty, but have been attempted because of the great interest in this facet of the problem. Using the assumptions accepted in the United Nations report,’® the 3.8 wyC of Sr*°/g calcium found in the one subject autopsied corresponds to a dose rate of 9.5 mr/year to the bone, and a doserate of only 3.8 mr/year to the bone marrow.Similarcalculations for Cs*** and Zn"? give a total of about 120 mr/year from the knowninternally deposited radioisotopes. This is to be compared with the dose rate from natural sources,'*® of which 44 mr/yearare attributed to K'°, radium, and meso- thorium distributed internally and 134 mr/year to cosmic rays and local external gamma sources. From local external gamma sources the Rongelap people as measured in March 1958 werereceiving about 250 mr/year and in August 1958, 500 mr year. (The latter increase was due to slight addi- tional short-lived fallout from a then currenttest series and the integrated dose for the year might be expected to be <(500 mr.) Discussion ACUTE AND SUBACUTE EFFECTS Theresults of the medical survey on the Rongelap people 4 years after exposure to fallout show that the people have largely recovered from the acute and subacuteeffects of their exposure and are making satisfactory readjustmentto their repatriation on Rongelap Atoll. The acute effects of radiation that were observed early in these people were indicative of significant exposure. Findings unquestionably related to their exposure were early gastrointestinal symptomsandsignificant depression of the peripheral blood elements commensurate with the calculated dose of 175 r penetrating gammaradiation, beta burnsof the skin and epilation from skin irradiation, and the acquisition of a low level body burden of radionuclides. In addition certain other findings were possibly related to their exposure such as (1) loss in weight of several pounds in most of the people during thefirst several monthsafter exposure and (2) suggestive evidenceof a slight lag in growth and developmentof exposedchildren duringthe first 3 years based on studies of height and weight and bone development. (A reevaluation of these studies is necessaryin viewof uncertainty in ages of someofthe children.) Other acute and subacute effects of whole-body irradiation which have been reported to occur have not been observed in the Marshallese. (1) Fertility, based on comparison of frequency of pregnancies, did not appearto be affected: (2) no deleterious effects were noted on the course of pregnancies; and (3) the four in utero irradiated babies appeared normal. It should bereiterated that completely negative statements cannot be made based onthese findings because of the pau-