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Biology and Medicine Studies involving the monitortng of the dtstribution of over the surface of the earth . have been extended. me analysis of gummed-paper samples from more than 100 stations h?s been continued, and a larger number of eoil samples from about 30 geographlcalloCatfons Outside the United States' are being analyzed by the New York Health and Safetg Laboratory to determine their radiostrontium content. In addition, the discrepancy between data collected by ' pared to those from collection pots p l y e d at about 20 gummed-paper stations in the United States and abroad. Stations were selected for these com par he studies Ln a manner which would provide samples from a variety of climates. In .ae analysis of soil samples, stadtee are . being conducted to establish the reliability of chemical methods for estimating not only the ,I total strontium content but also the amount of strontium 90 avallable for plant uptake to the available calcium content. Distribution of Radiostrontium in Foodetuffa More Mormation is being collected from foreign countries for research on the dhtribution of radiostrontium in foodstuffe. Samples both of foods in the composite diet and of human urine are being collected in Turkey and the Philippines by survey teams of the Interdepart- . The samples w i l l be analyzed by the New York Health and Safety Laboratory. Mormation la also being collected on the foods which provide the major,source of cklcium, the per Capita conmental Committee on Nutiition for National Defense, in which committee AEC ie pirticipating. . , . sumption, and the average calcium content of each foodstuff. These data may help to determine the importance of such factors ga geographic location; calcium content of soile, and local dietary habits in the distribution of strontium 90 in foodstuffs. '1One of the major genetics projects supported by the AEC is the study of radiation-induced mutations i n mice. In the United States, the mouse genetics project at Oak Ridge National Laboratory supplies the most important data available on induced mutations in manhals, on which extrapolations to human popqations can be based. ect, which is now being expanded. To ensure that the Harwell and Oak Ridge projects a r e The'United Kingdom has also been supporting at Harwell a a m h e r mou6e genetics proj-
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. BIOLOGY AND MEDICINE complementary and thus produce the maximum amount of data, the British Medical Research Council planned to sponsor a conference at Harwell on April 26, 1957. Three AEC geneticists were selected to attend the conference. REPATRIATION OF THE RONGELAPESE The Commission h& determined that the degree of contamination on Rongelap Atoll has declined to an acceptable level for the return of the ROngelapeSe to their home island ae soon as rehabilitation procedures have been completed. The Rongelapese, the last of the Marshall Islanders to be returned to their home island, were evacuated from the atoll after the fallout of radioactive fission products from the March I,1954, detonation in the Eniwetok Proving Since their exposure to radioactive fallout in 1954, the Marshallese have received four complete medical examinations.’ The most recent examination was made in March 1957. Preliminary reports on this examination indicated no illnesses or other clinical conditions which could be related to radiation effects, and the people appeared to be recovering satisfactorily from radiation exposure. it appeared that the blood cell counts were about equal to those in the unexposed people cations that pigment was returning .in burn areas. There w a s no evidence of any malignancy in any of the scars resulting from radiation b u m . Blood counts. Although statistical &alyses of blm-d examinations had not been completed, Skin b u m from beta radiation showed continued improvement,- add there were new hdi- ’ ‘ Body radioactivity. Because urinalyses made in 1956 showed little‘remaining body radioactivity, a more sensitive measure of residual activity was used in the 1957 examination. Four persons from Rongelap, two from Utirik, and one unexposed person from Majuro, who . served as a control for the experiment, were,brought to ArgoMe National Laboratory, where, total body radioactivity was measured in the Human Radiation Detector (“Iron Room”). Detectable amounts of activity were stlll p r e ~ e n t ,but they were only several times higher than’ those found in people in other parts of the world and were well below the accepted tolerance Deaths. The only deaths among the Rongelap people since the 1956 survey were one still-birth and the death of an infant a few hours after birth as a res& ,of infection. These deaths were not believed to be related to radiation effects. . Utirik. About 130 people who bad been exposed to slight amounts of fallout on the island of Utirik were also examined. They were found generally to be in good health, with no ill- . nesses or clinical conditions which could be related to radiation effects. Radiation could not be established as a factor Fn the 6j.k deaths which had occurred on.Utirik during the .threeyear period. This death rate was not considered to be unusual. External Gamma Dose Rates The radiation survey of Rongelap Island in July 1956 showed gamma values ranging from 0.2 to 0.5 milliroentgen per hour, with an average of 0.4 milliroentgen per hour. ,Estimates Of decay indicated that dose rates at the time of repatriation will be less than 30 miiliroentgeM. as also estimated that the gamma dose on Rongelap will be
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for the first year of reoccupation and will gradually decline thereafter. The Rongelapese who go on fishing expeditions to other islands could be exposed to levels of radioactivity higher than those of Rongelap; however, much of their time is spent on fishing boats over waters with gamma activity near background values. Thus the external gamma radiation recelved by the Rongelapese as a whole can be expected to be initially 0.5 roentgen or less per year. There is no radiation standard which applies directly to the Rongelap situation. However, standards established for normal atomic energy activities involvhg much larger numbers Of people may be of some significance in evaluating the Rongelap data. For occupational conditions, the National Committee on Radiation Protection and Measurement Tecommends4that adult workers not be exposed to more than 0.3 rem (roentgen equivalent for man) of whole body radiation per week, or a 13-week dose of 3 rems when tKe weekly limit is exceeded. This standard is further restricted by an age qualification, which provides that the maximum permissible accumulated dose in rems, at kny age, is equal to five times the number of years beyond age 18, provided no annual increment exceeds 15 rems. Thus, for persons over 18 ' years of age the accumulated maximum permissible dosage is 5(N-18) rems, where N Is the age. This standard applies to all critical organs except the skin, for which the value is dobble. I For a large population, in contrast with the small group of Rongelapese, the maximum.permissible exposure i s an average of 14 million rems per million persons during the period -.. from conception up to the ag ,and one-third of that amount in each decade thereafter. Food Supply and Body Content of Strontium 90 . Marshallese., Analysis of the results from all the Pacific Islands surveyed shows a decline of strontium 90 with the passage of time, except'in the land crabs. Additional collections of land * crabs will be made on Rongelap to establish the reason for the increase in strontium 90 acMaximum permissible exposure to strontium 90 for the general popuIation, in terms of maintained level in the body, is I00 Sunshine Units, (100 micromicrocuries of strontium 90 per gram of calcium). Exposure of the Rongelapese can be reduced by eliminating land c r a h from the diet and by reducing the consumption of such native plants as pandanus. Because only a part of the strontium 90 will go from food to bone, these measures may limit the ultimate bddy burden for the Rongelapese to substantially less than 100 Sunshine Units. Swine, chickens, ducks, and rats have continued to live on Rongelap during the period of highest strontium 90 contamination in the soil-plant-animal cycle. Examinations of rats collected and sacrificed two years after th'e initial fallout show no gross or pathological changes Strontium Qb is the radioactive i'sotope of princip in the food chain of the When the Rongelap people a r e returned to their home island, they will be given regular monthly medical examinations by local health'personnel and an annual examination by a physician from the United States. A dispensary will be maintained for regular health seryices. Any unusual body accumulation of strontium 90 will be detected before harmful effects result. A summary report of the several biological surveys made of the Marshall h n d s is being prepared by the AEC Naval Radiological De
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- Plans have been maae iui processes on plant and animal be made to determine the relal Climatic data will be collected humidity. Indigenous soil fact( and aquatic features will be st animal life will include the del terns; plant and animal popula transfer of mineral and organ