March 1957 Medical Survey of Rongelap and Utirik People Three Years After Exposure to Radioactive Fallout

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MARCH 1957 MEDICAL SURVEY OF RONGELAP AND UTIRIK PEOPLE THREE YEARS AFTER EXPOSURE TO RADIOACTIVE FALLOUT MAYNARD EICHER, 6 AND HYMAN HECHTER 7 with the technical assistance of IBrookhaven National Laboratory, Upton, New York 2Nationallnstitutes of Health, Bethesda, Maryland 4Armed Forces Special Weapons Project, Washington, D.C. 6Naval Medical Research Institute, Bethesda, Maryland 7Naval Radiological Defense Laboratory, San Francisco, California BROOKHAVEN NATIONAL LABORATORY

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This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above "person acting on behalf of the Commission" includes any employee or contractor of the Commission to the-extenrthat such employee or contractor prepares, handles or distributes, or provides access to, any information pursuant to his employment or contract with the Commission. Available from the Office of Technical Services, Department of Commerce,

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MARCH 1957 MEDICAL SURVEY OF RONGELAP AND UTIRIK PEOPLE THREE YEARS AFTER· EXPOSURE TO RADIOACTIVE FALLOUT This report presents the results of a medical survey carried out in March 1957 on the Marshallese people who were accidentally exposed to radioactive fallout in March 1954. The accident occurred following the detonation of a large thermonuclear device during experiments at Bikini in the Pacific Proving Grounds. An unpredicted shift in winds caused deposition of significant amounts of fallout on four nearby inhabited Marshall Islands and on 23 Japanese fishermen aboard their fishing vessel, the Lucky Dragon. Sixty-four inhabitants of the island of Rongelap, 105 nautical miles away from the detonation, received the largest fallout exposure among the inhabited islands: an estimated dose of 175 r whole-body gamma radiation, beta lesions of the skin, and epilation from contamination of the skin and slight internal absorption of radioactive material. The Japanese fishermen probably received a similar exposure, although estimation of their dose is much less certain. Also 18 Rongelap people away on a nearby island (Ailingnae), where less fallout occurred, received only about half this exposure. Twenty-eight American servicemen on an island (Rongerik) further away received about the same amount of radiation as did the 18 people on Ailingnae. Lastly, 157 Marshallese on Utirik Island, some 200 miles distant, received only about 14 r whole-body radiation. The fallout was not visible on this island and no skin effects were The initial findings have been reported on the Marshallese and Americans 1 and the Japanese fishermen. 2 Subsequent examinations of the Rongelap people have been reported at the following times after exposure: six months,3 one year: and two years, [. The present report concerns the examination of the Rongelap and U tirik people three years after exposure to fallout radiation. In addition examinations were carried out on an unexposed comparison population. SUMMARY OF PAST FINDINGS The foliowing is a brief summary of the past findings which can be found in detail in the referDuring the first 24 to 48 hr after after exposure, about two-thirds of the Rongelap people experienced anorexia and nausea and a few vomited and had diarrhea. At this time many also experienced itching and burning of the skin and a few complained of lachrymation and burning of the eyes. Following this, the people remained asymptomatic until about two weeks after the accident, when cutaneous lesions and loss of hair developed, due largely to beta irradiation of the skin. The effects of the radiation can best be summarized under three headings according to the mode of irradiation: penetrating irradiation, skin irradiation, and internal irradiation. The people on the island of Rongelap received an estimated whole-body dose of 175 r gamma radiation. Depression of peripheral blood elements ~)Ccurred as follows (see Figures 7-15): Lymphocytes fell promptly and by the third day were 55% of control values (unirradiated Marshaliese) in adults, and about 25% in children. There was only slight recovery by six months. Through the two-year examinations the mean val ues of these cells were still below the control levels. At two years the lymphocytes were about 75 to 80% of the mean level of the comparison NeutTophils fluctuated considerably during the first few weeks but fell gradually to a low of about 50% of control values by the sixth week after exposure; recovery was slow. At six months counts

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were still below control levels, but by one year post-exposure they had returned to the level of the Platelets fell to about 30% of the control values by the fourth week. By six months they had reached 70% of the controls; at one year the mean platelet count was still below that of the control population but slightly higher than at the sixmonth survey. At two years the platelets, though still slightly below the control level, showed some further increase over the one-year level. The depression of blood elements in the Ailingnae group who received an estimated dose of69 r was similar to that in the other group except that it was less marked. Even though the dose ofirradiation received by the Utirik people was quite low (about 14 r), a slight depression of platelets was observed during the first month post-exposure. Changes in the hematocrit were not remarkable in any of these groups. Clinical observations revealed no disease processes or symptoms which could be attributed to radiation effects aside from skin lesions, loss of hair, and early symptoms. The diseases encountered were no more' severe or frequent in the irradiated than in the nonirradiated population even during the period of greatest depression of the peripheral blood elements. Up until the two-year examination no deaths had occurred among the irradiated people. It was difficult to evaluate the effects on fertility; however, a number of apparently normal babies were born and further pregnancies occurred. No opacities of the lens or other eye changes were found that could be attributed to irradiation. The height and weight of the irradiated children were slightly less than those of the unirradiated children of the same age, but because of the small numbers of children involved, no definite statement could be made. Beta Irradiation of the Skin No accurate estimate of the radiation dose to the skin could be made. Lesions of the skin and epilation appeared about two weeks after exposure, largely on parts of the body not covered by clothing. Most of the lesions were superficial; they exhibited pigmentation and dry, scaly desquamation and were associated with little pain. Rapid healing and repigmentation followed. Some lesions were deeper, exhibited wet desquamation, and were more painful; a few became secondarily infected. Repigmentation gradually took place in most instances, and some of the healing lesions, particularly on the back of the neck, developed hyperpigmentation of a grayish, dusky color and a thickening of the skin with "orangepeel" appearance. At one year, however, this type of pigmentation was greatly reduced. Deeper lesions on the dorsum of the feet continued to show lack of repigmentation, with scarring in some cases. At two years post-exposure 15 cases continued to show residual skin effects largely in the form of pigment aberrations, and some atrophy and scarring. Histopathological studies of the skin showed changes consistent with radiation damage. A common finding in acute lesions was spotty transepidermal damage accompanied by atrophy and flattening of the rete pegs with areas of relatively normal skin between. The dermis was much less affected than the epidermis. Biopsies taken on later surveys showed considerable improvement, but with some persisting changes. * In no case was there evidence of any premalignant or malignant change. Pigmentation of the semilunar area of the fingernails and toenails was observed in about 90% of the people about three weeks after exposure. By six months pigmentation had largely grown out with the nail and had disappeared in most cases. Radiochemical analysis of numerous urine samples of the exposed personnel showed some degree of internal absorption of radioactive materials, probably brought about through eating and drinking contaminated food and water. Calculations of the body burden of these materials, however, showed that the concentration was too low to result in any serious effect. Analysis of urine samples six months after exposure showed only barely detectable radioactivity present in some cases. At two years radiochemical examination of pooled urine samples showed Sr 90 =0.6 and Ce144_Pr144 = 7.0 disintegrations per minute per 24-hr sample. (The samples were not analyzed *In some sections acanthosis, absence of pigment in the basal layer, and atrophy a~d benign dyskeratosis were noted in the stratum spinosum of the epidermis. Changes noted occasionally in the dermis consisted of areas of homogenization and increased density of coll~gen, alteration in the distribution of nmcopolysaccharide, presence of mucin in areas of degeneration, and cap-

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Figure. 1. Medical team. for Cs 137 . ) These values are far below the accepted maximum permissible body burdens. The examination of the Rongelap people was carried out at the Marshall Islands Memorial Hospital at Majuro, Marshall Islands. (The people have been quartered at Majuro Atoll since the initial examinations were completed at Kwajalein.) In addition to the irradiated group, a comparison group of unirradiated Rongelap people was also examined. The medical team consisted of nine American physicians and scientists, one Marshallese practitioner, and six technicians (Figure 1). Continuity of these studies has been aided by the fact that several members (physicians and technicians) have been with the team since the initial studies. This is also important in regard to insuring standardization of techniques from year to year (particularly in regard to the hematological studies). Following a three-week period of examinations at Majuro, the medical team proceeded via Navy LST to Utirik Island (some 350 miles distant)

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where 144 people were examined. The ship ~erved as a base of operations and laboratory (Figure 2). The physical examinations at Utirik were carried out in tents ashore (Figure 3). Several unfavorable factors associated with the examinations should be mentioned: 1) The language barrier made the examinations difficult since very little English is spoken by the Marshallese. However, sufficient interpreters have been available to assist the medical team. 2) The lack of vital statistics from the Marshallese imposes a serious difficulty in interpretation and evaluation of the medical data. Such statistics would be extremely helpful in evaluating the long~term effects of radiation. In recent years records of births, deaths, etc., have been kept by the health aids or magistrates and supposedly forwarded to the district administrator; however, such records have been poorly kept or lost and thus vital statistics are practically nonexistent. 3) Another factor was the uncertainty of exact ages of some of the Marshallese, particularly in the older groups, largely due to lack of written birth records. Except for the first, birthdays are little _ 4) The medical status is also complicated by unhygienic living conditions evidenced by the presence of parasitic infestation, chronic skin diseases, and extremely poor oral hygiene. Possibly dietary deficiencies also exist (this will be further evaluated on later surveys). 5) During the course of these studies over the past three years, difficulties have been encountered in obtaining what could be considered as entirely adequate populations to act as comparison groups for the irradiated people. Two separate comparison groups had been used in the past, each comparable to the exposed group in size and closely matched for age and sex. These groups are represented in hematological graphs of this report as A and B (B, and B2). The A population was chosen at Majuro at the time of the initial examinations, but at six months postexposure it was found necessary to select another group, the B, group, since many members of the A group were missing (had migrated to other islands, etc.). At the two-year examination, the B group (B2) was used again even though about one-third of the group was missing. The people - in the A and B groups were mostly Marshallese from the eastern chain of the Marshall Islands and are considered to be anthropologically slightly differe~t from people of the western island chain to which the Rongelapese under study belong. 8 . At the time of the present survey, it was found that during the preceding year the Rongelap population had doubled at Majuro Atoll by the influx of other Rongelap people who had been away from the island at the time of the accident but had since returned. This situation was most fortunate, since this grou p of people was of the same stock (blood relatives) and was living with the population under study under the same environmental conditions. These people provided a uniquely appropriate group to serve as a comparison population. Moreover, they matched reasonably well for age and sex and would be available for future examinations since they planned to return to Rongelap Island to live. This group is represented as C in the graphs. For the growth and development studies, as many of the old B-group children as could be found were examined in addition to the Rongelap children in order to expand the number for comparison and furnish further longitudinal data for yearly studies. Histories were taken by a Marshallese practitioner with particular emphasis on the interval history during the past year. Complete physical examinations were carried out including examination of the skin with color photography and biopsies of selected lesions; ophthalmological studies including slit-lamp observations, visual acuity, and accommodation; growth and development studies in children (less than 20 years of age) including anthropometric measurements and x-ray examinations of the left wrist and hand for bone development studies; audiometer examinations on all over 30 years of age; ECG records on all over 40 years of age; and x-ray examinations as deemed necessary. Hematalogical examinations included three· ential, platelet counts (phase microscopy), and hematocrit (microhematocrit method) done at about weekly intervals. (Only one complete blood study was carried out on the Utirik people except for repeat examinations on those with abnormal counts.) In addition, sickling tests (sodium bisulfide technique) were run, and smears were obtained for reticulocyte counts, alkaline phos-

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phatase studies, and basophil counts ( 4000 cells). Blood was obtained for hemoglobin classification. Sera were obtained for protein determinations by proteinometer and copper sulfate techniques; A-G ratios and electrophoretic studies in 37 people; and cholesterol and creatinine determinations. Eight irradiated and nine unirradiated people were used in a study of immunological response to tetanus toxoid. The primary stimulus of tetanus toxoid had been given 2V2 months previously. Sera were obtained just prior to the second injection of toxoid and then six days later. Subsequently, tetanus toxin-antitoxin titrations of the sera were obtained for the two groups in mice by the methods previously described. " Routine urine analyses were carried out on …