Medical Survey of Marshallese People Five Years After Exposure to Fall-Out Radiation

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T D‘a”$’Reprinted from IMMEDIATE AND LOW LEVSLEFFECTSOFIONIZINGRADIATIONS. Conference held in Venice, June 1959. T A Special Supplement to the International Journal of Radiation Biology. Medical survey of Marshallese people five years after exposure d! -, Medical Research Center, Brookhaven National Laboratory, Upton, New York A medical survey of the .Marahallese people in March 1959, five years after exposure to falI-out radiation, showed that the people had recovered from the acute effects of their radiation exposure and appeared to be generally in good health. The following specific statements can be made in regard to their radiation health status: 1. No illnesses or diseases were found that could be directly associated with acute radiation effects. 2. One case of cancer and three deaths have occurred, but with no direct relation to radiation effects. -f miscarriages and still-births appears to be somewhat higher than m the unexposed Marshallese, but a deficiency of vital statistics precludes definite conclusions as to whether or not this is a radiation effect. 4. Suggestive evidence of slight lag in growth and development of exposed children noted previously is being re-evaluated on the basis of better age data obtained during the past survey. @’/~ 5. Blood-platelet levels are within the normal range, but somewhat below that for the unexposed population. 6. Only 12 cases show residual changes in the skin from beta-bums. None show any evidence of cancerous change. 7. Possible late effects of radiation, such as shortening of life-span, premature ageing, increased incidence of leukaemia and malignancies, increased incidence of degenerative diseases, opacities of the lens of the eyes, and genetic changes have not been observed. An attempt to measure ageing by a semi-quantitative clinical approach is presented. 8. The original body burdens of internally-absorbed fission products appears to be too low to have produced any acute or long-terns effects. 9. The return of the people to the slightly contaminated island of Rongelap has caused some increase in body burdens of 137Caesium, 86Zinc and tostrontium. However. the levels are far below the acceuted m~ximum permissible limits and it is not believed any untoward effects will result. This discussion concerns a brief account of the present health status of the Rongelap people, \vho were exposed to the heaviest dose of radiation from accidental fall-out in h4arch 1954 following detonation of an experimental nuclear device at Bikini in the lvlarshall Islands. An unpredicted shift in winds caused deposition of significant amounts of fall-out on four nearby inhabited Marshall Islands and on 23 Japanese fishermen aboard their fishing vessel, the Lucky Dragon (see figure 1). Sixty-four inhabitants of the island of Rongelap, 105 nautical miles away from the detonation, received the largest minate beta-ray dose to the skin from contamination of the skin and internal t This work is supported by the U.S. Atomic Energy Commission.

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absorption of radioactive fission products. Eighteen Ron,gelap people away on a nearby island (Alinginae), ;here less fdi-outoccurred, received about 69 r with proportionately less contamination of the skin and internal absorption of radionuclides. Discussed in earlier reports (Cronkite, Bond and Dunham 1956, Conard, l’vIeyer, Rail, Lowrey, Bach, Cannon, Carter, Either and Hechter 1958) were 28 American Servicemen on Rongerik .4to11who received about 70 r and 157 Marshallese on Utirik Atoll \vho received about 14 r. The exposed people were evacuated to Kwajalein in the .Marshall Islands by air and sea about two days after the accident. Extensive examinations were carried out during the first three months after exposure, and these findings have been Figure 1. Map of fall-out area, Marshall Islands, March 1954. reported in detail (Cronkite et al. 1956). In view of the radioactive contamination of their home island of Rongelap, the people were subsequently moved to a village provided for them at Majuro .\toll, where follow-up medical surveys \vere carried out and reported on at six months (Bond, Comu-d, Robertson and 1955), two years (Conard, Huggins, Cannon, Lo\vrey and Richards 1957) and at three years (Conard et al. 1958). By June 1957 radioactivity levels on Rongelap \vere considered safe for habitation, and the people were returned to their Sutow, W;oIins, Lowrey, Urschel, Barton, GoIdman, Hechter, Either, Carver and Potter 1959) was carried out at Rongelap Atoll. By 1956 a large group of unexposed Rongelap people (reIatives) had joined the exposed Rongelap people and returned to Rongelap Island Ivith them. This unexposed group has increased in size to 200 people and served as a much better comparison population group

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Effects of fall-out radiation on Marshallese 271 than did the. earlier comparison group of people, which was randomly selected The latest findings are based on the annuaI medical survey carried out at Rongelap in March 1959 at five years after exposure. About 100 exposed people including their children and 200 unexposed people were examined. Since the data are not completely analysed, the statements made concerning this survey must be considered as preliminary in nature. The survey was conducted by a 20-man medical team from various institutions in the United States under the direction of Brookhaven National Laboratory~. The examinations included medical histories, complete physical examinations, and blood and othe? laboratory examinations. In addition body burdens are being determined from spectrographs of gamma-ray activity of 175 Rongelap individuals from numerous urine samples for radiochemical analyses. 2.1. Acute eflects of gamma-irradiation During the first 24 to 48 hours after exposure about two-thirds of the Rongelap people experienced anorexia, nausea, and a few vomited and had diarrhoea. h4any also experienced itching and burning of the skin, and a few complained of lachrymation and burning of the eyes. FoIlowing this they remained asymptomatic until about two weeks after the accident, when DAYS Fo YEARS TIME AFTER EXFOSURE Figure 2. XIem neutrophil and white blood counts of exposed Rongelap people from time of exposure through five years’ post-exposure. Stars represent mean values of cutaneous lesions and loss of hair developed, due largely to beta-radiztion of the skin. It \vasapparent when the people \vere first examined, a few days after exposure, thzt the lymphocytes \vere considerably depressed and that significant doses of radiation had probably been received. The dose of radiation proved t The material presented in this report represents findings by a large number of people who have participated in past surveys.

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to be sub-lethal, since no deaths occurred ~vhich could be directly related to radiation exposure. However, it is probable that the dose was in the high sub-lethal range, judging by the degree of haemopoietic depression that DAYS MO YEARS TIME AFTER EXPOSURE Figure 3. Mean lymphocyte counts of exposed people from time of exposure through tive years’ post-exposure. Stars represent mean values of comparison populations. TIM E AFTER EXPOSURE Figure 4. Mean platelet counts of exposed Rongelap people from time of exposure through five years’ post-exposure. Stars represent mean values for comparison populations. developed. In addition radiochemical analyses of the urine also sho~ved that definite amounts of radioactive material had also been absorbed internally. The changes during the past five years in the mean peripheral blood levels of the more hea~-il>-exposed group of 64 Rongelap people receiving approximately 175 r of whole-body radiation are shovm in figures 2, 3 and 4. The w-bite blood cell levels of the exposed group ~vere depressed to about half the

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Effects of fall-out radiation on Marshallese 273 level of the unexposed comparison population during the first two months, but did not result in any observable untoward effects in the people. No increased incidence of infection was observed, and no therapy (antibiotic or otherwise) was given specifically for their leukopenia. Mean blood-platelet levels were also significantly depressed to about 30 per cent of the unexposed levels by the fourth week. No bleeding associated with the platelet depression was noted, and no blood transfusions were necessary. Erythrocytes as measured by haematocrit levels were not significantly depressed. Following this early depression, the blood elements slowly recovered, some elements faster than others. The neutrophils were first to reach comparison population levels by about one year post-exposure (figure 2). The lymphocytes returned more slowly, and even at two and three years’ post-exposure the mean levels were slightly below the unexposed mean levels (figure 3). By four years they had reached the unexposed levels and remained so at the time of the five-year survey. Platelet levels showed the slowest recovery (figure 4). A rapid recovery trend followed the early depression, after which there was slower increase with mean levels remaining consistently below the unexposed mean population level. At the five-year survey the males were about 13 per cent and the females 11 per cent below the corresponding mean levels of the comparison population, though the individual platelet counts were within the normal range. The mean red blood count, hemoglobin and haematocrit levels, were about the same in the exposed as in the unexposed group. The 18 Rongelap people who had received about 70 r at Alinginae Island showed less severe early haemopoietic depression, but have also shown a similarly slow recovery rate of lymphocytes and platelets, as noted in the more heavily exposed group. The incidence of diseases, infectious or non-infectious, has remained about the same in the exposed as in the unexposed population. Three deaths have occurred: one in a 46-year-old man during the second year after exposure from hypertensive heart disease which had been present at the time of exposure; the second in a 78-year-old man, at three years after exposure, of coronary hem-t disease complicating diabetes; and the third in a 36-year-old man, at four years after exposure, of acute varicella. During the first six weeks over half of the exposed people lost weight, even though their diet \vas satisfactory and appetites good during this period. This possibly reflects an effect of radiation exposure on general metabolism. However, factors associated with a change in environment cannot be ruled out as being There were no abnormalities noted at birth in four babies irradiated in utero; two in the first trimester, one in the second trimester, and one in the third The five-year survey reve~led that the people were generally in a good state of health and nutrition. The incidence of diseases were about the same in the exposed and unexposed groups. One case of ovarian cancer developed during the past year in a 61-year-old exposed woman. 2.2. Late effects of gamma-radiation Late effects of radiation exposure constitute an important part of the examinations in the ~Iarshallese. Very little is known about such effects in

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human beings. From experiences with the Japanese exposed at Hiroshima and Nagasaki and from animal studies, certain late effects of radiation may possibly develop in the lvlarshallese. Results of observations for such effects will be presented accompanied by appropriate discussion related to findings of others. Thus far the three deaths in the exposed group represent about the same death rate as has been observed in the Marshall Islands as a whole over the same period of time (about seven deaths per 1000 per year). Numerous investigators have reported shortening of life-span of animals exposed to acute and chronic radiation (Blair 1956, Bennett, Chastain, Flint, Hansen and L&vis 1953, Brues and Sacher 1952, and others). Chronic exposure of radiologists in the LTnited States was reported to result in life-shortening compared with other physicians (Dublin and Spiegelman 1948, Warren 1956). In view of the above findings, some life-shortening may be expected in the Marshallese, though in view of the small size of the population a number of years will no doubt be required before such an effect of radiation can be evaluated. 2.2.2. Premature ageing and degenerative diseases From observations over the past five years the impression is that the exposed Marshallese dd not appear to have aged faster or appear older than unexposed Marshal]ese of the same age. h~o doubt the subtle changes which occur with ageing would be difficult to detect over this period of time. The incidence of degenerative disease has been about the same in the exposed as in the unexposed An attempt is also being made to study ageing from a more quantitative clinical approach. Certain criteria usually associated with ageing that can be easily obtained on physical examination are recorded as nearly quantitatively as possible, either by direct measurement or estimation of degree of severity of criteria in a scale from Othrough 4+. Though the work is in the early stages and only preliminary analyses have been carried out, it might be of interest to outline some of the criteria which are being investigated. Skin: Special calipers with spring tension have been designed for measurement of (a) looseness and (b) elasticity. Looseness is measured in millimetres height of the fold of skin anteriorly at the junction of the neck and chin. Elasticity or resilience of the skin is determined by clamping a fold of skin on the back of the hand for one minute, releasing the calipers and measuring the time in seconds for retraction of the fold to the normal skin level. (c) Senile changes in the skin, such as keratosis, pigment changes, and warts (O–4 + ). Eyes: (a) Visual accommodation measured in dioptres, (b) arcus senilis Hearing: Loss of hearing at 4000 frequency. and diastolic blood-pressure readings. Vigour: (a) Vital capacity of lungs, height, (b) hand-grip strength, as measured with a hand dynameter in kilograms. lYeuromuscular junction: h-umber of depressions of the key of a hand tally (blood counter) in one minute.

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A preliminary study of the data by plotting the values for each age criteria against age (at five-year intervals above 20 years) showed no consistent differences between the exposed and unexposed groups. However, the numbers of people are not large, and no statistical treatment of the data has yet been done. A general idea of the trends of several of these ageing criteria may be obtained from figure 5. After further testing of the age dependence and variability of the data, a uniform scoring system will be applied and the criteria weighted to GREYING OF HAIR Figure 5. Plots of ageing criteria against age at five-year intervals. obtain a total score on each individual which may approximate their ‘ biological age ‘ for a comparison with their actual age. Further criteria may be added. Particularly needed are further tests of functional status or vigour which can be measured. It is not known if the type of criteria chosen are necessarily associated with ‘ radiation senescence ‘, but the approach is believed worth investigating, since many animal studies indicate late radiation changes that closely resemble advanced or premature ageing (Blair 1952, Cassarett 1956, One case of ovarian cancer (verified by biopsy at operation) in a 61-year-old exposed female was noted during the past year, the first case of malignancy noted in either the exposed or unexposed group. There is no reason to incriminate radiation in the aetiology of this case, particularly in view of the early time of appearance. Since leukaemia is the earliest type of neoplasia associated with radiation to develop, examinations in the Xlarshallese have included blood smears, stained for alkaline phosphatase of neutrophils and basophil counts in 4000 white cells per …