Medical Survey of the People of Rongelap and Utirik Islands Eleven and Twelve Years After Exposure to Fallout Radiation

Page 1

OF RONGEIAPAND UTIRIK YEARS AFTER EXPOSURE with the technicalossistancoof AND AROMTI HICKIN6, PRACTITIONERS with tho technicalassistanceof B RO OK HAVEN NATIONAL LABORATORY UPTON, NEW YORK 11973

Page 2

other Background Infhrnmtion .................................................................................................... The Radiation h to the Thyroid Glan& ............................................................................ Dietary Iodke and Urinary Excretion of ldine ................................................................ Discussion of Previous Thyroid Studia ................................................................................

Page 3

Thyroid Function Tcsta Related to Thyroid Abnorrrialiti= and Growth Retardation ........ 33 Results of Thyroid Hormone Therapy ............................!....................................................... 40 Diacusaion of Thyroid Findings 40............................. ........ .....................................................4 Neurological and Neuromuscular Function ........................................................................ 44 Raults of Aging Studies ...................... ..................................................................................... 46 Children of Exposed Parenta... ..................................................................... ............................ 55 Statistical Analysis of Rongelap Blood Data ............................................ ............................... 55 Tat for Australia Antigen ............................................................................... ........................ 58 Estimation of Internal Body Burdens of Radionuclida .............................................................. 58 Radiochcmical Analys&of Uri Ie.............................................................................................. 59 Raults and Diacu.uion of Body Burden Estimation. ............................................................... 61 Comparison of ‘“~ Levels in Marshallac and Alaakan Eskimos................................... . .... 63 Radiochemical Analysis of coconut Crak .............................................................................. 63

Page 4

Interval Mcdkal Hktoq ................................................................................................................ Estimation of Internal Body Burden ofkdionucKda ................................................................ APPENDIX2. UCRL 12273- Estimate of Radiation Dose to Thyroi& of the Rongclap Children Following the Bravo Event and Calculation of Urinary Radioiodine APPENDIX 3. Individual serum Iodine Dcterminatiotu of Mamhall Mand Population Under Study ........................................................ 86 APPENDIX 4. Urinary Iodine Excretion. ....................................................................................... 93 APPENDIX 5. Cholesterol Levels .................................................................................................... 94 APPENDIX 7. Malignancies Recorded in Marshall Islands, May 1952- October 1962 and Number of Patients With Malignant Ncoplastns Discharged From Hospita~ APPENDIX 8. Rongelap Group and Control Mean Blood Counts at Varioua Tlma After Exposure. ........................................................................... 112 APPENDIX 9. Ailingnae Group and Control Mean Blow.1Counts APPENDIX 10. Utirii Group Mean Blood Counta at Various rim= After Expaurc .... .............. 114 APPENDIX 11. Individual Hematological Findings, 1965.. ................................. ................. ........ 115 APPENDIX 14. Chromomme Studies on Mamhallac People Expxd to Fallout Radiation ...... 137 APPENDIX 15. Total Blood and Red Cell Volume Data ................................................................ 149 APPENDIX 16. Studicson Australia Antigen in Microncsian Populatioru .................................... 150 APPENDIX17. Gamma Spectrographic Data, Rongelap People, 1965, ....................................... 154 Following an Acute Ingation of Rongelap Food ................................................... 159

Page 6

MEDICALSURVEYOF THE PEOPLEOF RONGEIAPAND UTIRIKISLANDS The results of a medical survey of the people of Rongelap in the Marshall Islands, carried out in March 1965 and March 1966, 11 and 12 years after the accident, are presented in this report. These people had been accidently exposed to fallout radiation following a detonation of a high yield thermonuclear device during experiments at Bikini in the Pacific Proving Grounds in March 1954. An unpredicted shift in winds caused a deposition of significant amounts of fallout on four inhabited Marshall Islands to the east of Bikini (see Figure 1) and also on 23 Japanese fishermen aboard their fishing vessel, the l+ucky Dragon. Of the inhabitants of the island of Rongelap, 105 nautical miles away from the detonation, 64 received the largest fallout exposure: an estimated dose of 175 rads of whole-body gamma radiation, contamination of the skin sufficient to result in beta burns, and slight internal absorption of radio- ) active materials through inhalation and ingestion. Another 18 Rongelap people away on a nearby island (AiIingnae), where less fallout occurred, reMarshall Islands, March 1, 1954. ceived only an external gamma dose of about 69 rads. There were 28 American servicemen on the island of Rongerik further to the east who received about the same amount of radiation as did the Rongelap people on Ailingnae. Lastly, 157 Marshallcse on Utirik Island, about 200 miles further east, received an estimated 14 rads of whole-body radiation. The fallout was not visible on this island and no skin effkcts developed. The exposed people were evacuated from these islands by plane and ship about 2 days after the accident and taken to Kwajalcin Naval Base about 150 miles to the south, where they received extensive examinations for the following 3 months. During this period vigorous efforts were necessary to decontaminate the skin completely In view of the generally negative findings on the American servicemen, they were later returned to their duty stations. The Utirik people were also allowed to return to their home island, where radioactive contamination was slight enough to allow safe habitation. Because Rongelap Atoll was considered to be too highly contaminated, a tempoFigure 2. Marshallese bathing in lagoon at Kwajalein in March 1954 to decontaminate skin and hair after fallout

Page 7

rarv village was constructed for the Rongelap people (including the 18 from Ailingnac) on Majuro Atoll several huk~dred miles to the south, where they lived for the following 3% years and were examined at yearly intervals by a special medical team. In July 1957, after careful evaluation of radioactive contamination, Rongelap Island was considered safe for habitation. A new village was constructed, and the Rongelap people were moved there by Navy ship. The annual medical surveys have since been carried out on RongeA group of more than 100 Rongelap people, who were relatives of the exposed people but had been away from the island at the time of the accident, moved back with the Rongelap people to their home island and have served as an ideal comparison population for the studies. The number has since increased to >200. Following the initial survey of the Utirik people on Kwajalein in 1954, repeat surveys have been carried out on these people about every 3 yearn, including the 12year survey. In addition, during the past survey, as in the previous surveys, a visit was made to Kwajalein and Majuro Atolls for examination of a number of Rongeiap people now residing at these atolls, and also groups of children who represent parts of the control group used for the growth and development studies of the exposed children. The accumulation of data from these surveys is becoming increasingly voluminous. Since crmditions have not been favorable for performance of extensive statistical analyses or use of electronic computing procedures to store and manipulate the data, the annual survey reports published by this Laboratory are made as complete as possible. This report, therefore, includes a considerable amount of raw data, much of it in appendices, so that others may have an opportunity to make further calculations if desired. Table 1 lists exposure data on the various populations involved in the fallout. In the following summary, except where data are broken down into more detail, the exposed group includes the people exposed on Rcngelap and on Ailingnae (subject Summary of Past Findings Reports have been publishect on the medical findings of surveys made at the following times after exposure: initial examination,’ 6 month s,’ 7 years,’ 8 years,” and 9 and 10 years.’” Appendix 1 gives a more complete list of reports, including outside publications, on the results of medical surveys of the Marshallese exposed to fallout and includes a section on the radiation ecological studies of these Islands published largely by the University of Washington gToup. The following is a brief summary of the medical findings previously During the first 24 to 48 hr after exposure, about % of the people exposed on Rongelap Island experienced anorexia and nausea. A few vomi[ed and had diarrhea, many also experienced itching and burning of the skin, and a few complained of lacrimation and burning of the eyes. None of these symptoms was noted in the Utirik people ( l-t-rad group). Following this, the people remained asymptomatic until about 2 weeks after the acc]- dent, when cutaneous lesions and loss of hair developed, due largely to beta irradiation of the skin. 1( was apparent when the people were first examined, a fcw days after exposure, that the lyn]- Summary of Fallout Eflects Group* Composition Fallout obsrrvcd rtosv (rmls I Extent nfskin leSIIIILS Rongclap 64 Marshallese Heaw (snowlikc) 175 Extensive Rongerik 28 Americans Moderate (mist like ) 78 Slight L’[ir]k 157 Marshallrsr None 14 No skin lesions or epllalit,!] lAlso exposed were 23 Japanese tishermen who received a sublethal dose,

Page 8

phocytes were considerably deprmed and that significant doses of radiation had probably been received. In addition to the whole-body dose of radiation and the beta irradiation of the skin, radiochemical analyses of the urine showed that measurable amounts of radioactive material had also been absorbed internally. The effects of the radiation can best be summarized under three headings according to the mode of exposure: penetrating irradiation, skin irradiation, and internal irradiation. One of the earliest findings indicative of a significant exposure in these people was lowering of levels of {ruko~yfrs and /datcltIs of the peripheral blood, This was most marked in the 64 people on Rongelap who had received 175 rads, and was less marked in the other groups receiving less exposure. The hemopoietic depression was roughly proportional to the dose of radiation received. Even in the 157 Utirik people who received only an estimated 14 rads, it was possible to distinguish slight pla!elet depression in the group as a whole. Thr smaller group on Ailingnae and Rongerik showed peripheral blood levels between those of the high and low exposu e groups. The chronological records of bkmd f ndings on the group exposed on Rongelap are pre.~ented in Figures 49, 50, 36, and 65 and Appendix 2, ~nd on the Ailingnae and Utirik groups in Appendices 9 ard 10, i.~mphopcnta of about half the level of the comparison Marshallese population was evident when the people exposed on Rongelap.were first examposure (see Figures 49, 50, and 65). In children showed a slight rise during the following weeks. The lymphocyte level showed a slight increase by I year. In the following year mean counts approached the levels of the comparison population but remained slightly below (see Figu-res 50 and .I”t-u(mphtl levels fluctuated considerably during the first month; possibly this was related to the prevalence of beta burns of the skin during that period. Neutrophil depression became evident by 5 and 6 weeks ‘pos: ex-posure (see Figures 49 and 65), with levels reaching about half that of [he comparison population in the adults and slightly lower in the children <5 years of age. This degree of neutropenia was insufficient to result in any apparent increased infectious processes, and, indeed, it was noted that neutrophilic leukocytosis was possible in people showing casual infections at this time. Neutrophil levels recovered more rapidly than lymphocyte levels :xl reached near control levels by 1 year. Subsequent annual surveys have revealed that recovery does not appear to have been complete, particularly in younger and older age groups, during the 10-year period. Early plo!clel counts showed less fluctuation than. . other blood counts and fairly consistently showed increasing depression, reaching levels of about 3@7G that of the comparison population by the 4th week. A spurt of recovery to about 759c of comparison levels occurred during the following few weeks, which was followed by slower recovery but with mean levels never reaching higher ‘!-tan 90 to 95% that of the comparison population during the 10 years post exposure (see Figures 56 and Ervthropoitttc depression has not been a consistent finding as with the leukocytes and thrombocvtes. Slight depression of red blood counts, hematocrits, and hemoglobin has been noted at times. flonc marrou’ smears taken at 6 months showed no gross abnormalities. Smears taken at 8, 9, an-i 10 years showed an alteration in the creased number of red cell prccu rsors. Depresion of peripheral blood elements in the Ailingnae and Rontgerili groups was not so pronounced as in the Rongelap group. However, a slight lag in complete reco~el y in the Ailingnae peripheral blood count has also been noted. The persistent depression of peripheral blood elements in the exposed people ‘makes it appear likely that there is _slight residual bone marrow damage. .4 general anrm~f tendency has been evitient in both exposed and unexposed Marshallese, PriceJones curtes, on the average. showed a sligh[ microcytic tendency. Serum iron levels have been generally normal, and the cause of this anemic tendency has been undetermined. RtIIiIAiocyIt counts have been about the same in the exposed as in the unexposed people. lesions of the skin, patchy epilation, and early gastrointestinal symptoms, revealed no clear-cut disease processes or symptoms which could be re-

Page 9

lated directly to radiation effects during the first few years post exposure. No prophylactic or specific therapy for radiation effects was ever considered necessary or given. Epidemics of chicken pox and measles that occurred during the first year showed no greater incidence or severity in the exposed than in the unexposed Marshalles people. During the first months post exposure about % of the exposed people exhibited loss o~weight of several pounds. This may possibly have been related to their radiation exposure, aIthough it was difficult to rule out possible effects due to change of At 3 years post exposure the immune response to primary and secondary tetanus antitoxin was tested and found not to be significantly different in the exposed compared with the unexposed popuThere were 10 deaths in the exposed populations over the 10-year period (see Table 6). Of these, 2 deaths were recorded as due to malignancies. The 10 deaths that have occurred in the exposed population represent a mortalify rate of 12.2 per 1000 population per annum, compared with 8.3 for the Marshall Islands as a whole ( 1960). The somewhat higher death rate in the exposed group is partly offset by the higher proportion of older people; those >65 years of age were originally 2090 in the exposed group and only 790 in the Growth and development studies on the children (height, weight, anthropometric measurements, and radiographic studies for bone age) have revealed slight retardation ir growth and develop ment in the boys exposed on Rongelap who were <12 years of age at the time of expsure, particularly those 12 to 18 months of age at exposure. Only slight immaturity was noted in the female children of this group. In studies of children born of exposed parent(s), it was noted that males showed a slight growth retardation and slightly lower levels of peripheral blood elements compared with male children of unexposed parents; however, this latter finding has not been evident since 1963. The slight growth difference does not appear to justify a conclusion that there is an association with exposure of the parent. It was difficult to evaluate the effects on fertility. However, a review of the birth rutc of the exposed groups over the past 10 years seems to indicate no noticeable effects of their exposure on fertility. The 50 births represent a rate of61 per 1000 population per annum compared with 37.3 for the Marshall Islands [ i 957). The incidence of mlscarrzagts and stillbirths in these exposed women was about twice that in the unexposed women during the first 4 years after exposure, but no difference has been noted since then (see Table 8). no outstanding differences between the exposed and unexposed groups. The Marshallese people appeared to hav~ less hypertension on the whole than is noted in people in the continental United ences between the exposed and the unexposed people, and about the same incidence as is seen in Ophthalmological surveys showed no remarkable differences be~ween the exposed and unexposed groups except possibly …