Current Status of Information Obtained from Plutonium Contaminated People (Los Alamos Scientific Lab, Univ. of Ca, Los Alamos, NM)

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Current Status of Information Obtained from Plutonium Contaminated People'. L o s Alomot Scientific fiboratory University of elifornia Earlier in this Congress Dr.Alvin Weinberg asked the following question, T a n man learn to live with fission?" Perhaps another way of phrasing this important question would be to ask if man can learn to live with plutonium and other actinide elements. There has been much interest and concern expressed about the potential toxicity and effects of plutonium and the actinide elements on man. Although there exists a considerable data base on the biological effects of plutonium on experimental'animals, there is a relative paucity of data existing for exposed human subjects. Therefore, we are placed in a situation in which we must extrapolate or project in some manner the effects of plutonium on experimental animals to man. Nevertheless, we do have some information concerning human subjects who were exposed to plutonium through occupational exposures. I shall attempt to review this information for you today. We should keep in mind that this kind of information, even though very limited, is human experience of the most relevant kind for establishing value judgments where inadequate data exist for formulating risk evaluations. There have been no recorded substantiated incidents of cancer production in man from the internal deposition of any plutonium isotope in the nuclear energy industry, even though internal depositions have occurred. This excellent record has resulted from effective control measures. Although some exposures occurred 30 years ago, we must keep in mind the relatively short time since exposure for many of these cases. There has been a reasonable number of individuals exposed t o quantities of plutonium at or near the maximum permissible lung or body burden. Although the exact levels of internal contaminition are uncertain, it is clear that this body of information represents a valuable resource for current and future study. Some work has been done on specific groups and other studies are in the process of gathering pertinent data forfuture useas thest populationsage. Another source of information on the effects (or lack thereof) is a group of persons who received plutonium during the mid-1940's. These are particularly interesting as data accrued for these persons provided the basis for the human excretion equations derived by Langham at Los Alamos. In addition, the injected levels were reasonably high and were retained in one case for 21 years. Still another source of information exists in the form of virtually the entire

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world's population, which has accumulated plutonium, although rather inefficiently, from previous and present atmospheric detonations of nuclear weapons. Past and current autopsy programs involving both occupationally and non-occupationally exposed persons will also furnish useful infomation on the uptake and concentration of plutonium in various body tissues. These data provide us with some insight on the efficiency of the human organism for incorporating plutonium and on its distribution among body tissues. In the case of occupational exposures, this data base will also allow us to make comparisons of the body burden withestimates based on bioassay data obtained dunngthe life of the subjects in question. The message I would like to leave with you i s that we have not obscrvcd any serious biological cons quena in man from occupational exposure to plutonium. The next logical question is, "How do you know?" or "Have you looked?" We have indeed looked and the record to date is quite reassuring. However, I would like to point out that the past is not always prologue,chetrful as that thought might be. Although the final answers arc not in, I would hasten to add that we now have information on people which has spanned almost three decades so that the argument of latency for certain late effects (how long does it take to produce a tumor) is losing impact in at least some of the cases I will MANHATTAN PROJECT EXPOSURES Since the discovery of plutonium over three decades ago, (I), some personnel exposures have occurred. Some have been studied and reported on in varying degree, both during life and after death. (H).One of the most interesting groups, because of both time since exposure and lev4 of exposure, is that of the Manhattan Project plutonium workers (IO). Twenty-five male subjects who worked with plutonium during World War I1 under very crude working conditions, as judged by today's standards, have been followed medically for the intervening years. Within the past several years, 2 1 of these men have been examined at the L o s Alamos Scientific Laboratory. In addition to physical examinations and laboratory studies (complete blood count, urine chemistry profiles and urine analysis), roentgenograms werc taken of the chest, pelvis, knee and teeth. Chromosomes of lymphocytes cultured from peripheral blood and cells shed from the pulmonary tract were also studied. Biomedical Work Related to Manhatun Pro&: Medical History and Examination Blood Chemistry Profiles

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inc specimens assayed for plutonium yicldcd cdculatcd body hurdcns which ~gcdfrom 0.00s to 0.42 pCi. 'Ihcsc cstimatcs o f body burden, on t h e itvcrqc, higher than earlicr cstimalcs based o n radioassay of urinc samplcs collcctcd in past, pcrhaps rcflccting unccrtaintics in thc models uscd t o estinliltc body rdcn from cxcrction data. .I-itblc 1 indicates thc kinds of information obtained B r n the Manhattan Project plutonium workcrs. Most. but not all, ol'thcse tcsts vc k c n conductcd cvcry four to fivc ycars sincc thc group has bccn studied. lis appars t o be a vcry hcalthy group of rncn in thcircarly to mid-fiftics.'Ihcre the radiation cxposurc. Exccpt far thc ailmcnts that one would expcct in a aup o f rncn of this agc, all subjects cxamincd wcre in rcmarkably good hcalth. IC man had a coronary occlusion but had recovcrcd and urds wcll compensated, d itnothcr of the original group died in 1959 of a coronary at agc 38. Another d ii hamartoma of the lung surgically removed without complication in 1971. A ird had a mclanoma of thc chest wall (regional lymph nodcs wcrc ncgativc). A urth had a partial gistrectomy frcc-hlccding ulccr. Sevcral had mild pcrtcnsion and modcratc obcsity and onc had gout. All rncn wcrc actively irking, mostly as succcssful cxccutivcs. More detailed information on this .rticular group of workcrs has been published (/1-!2). It is important to rcalize at thcse men worked under very crude working conditions asjudgcd by today's mdards. Figure 1 shows the building in which these rncn workcd in 1944and 145 as pan of the program to make the first nuclear weapons. f can issurc you I no adverse biological cfkcts that havc bccn dctcctcd which a n bcattributed

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that thcrc is probably a Iictor of 115.000 bctwccn safety constraints in this building and thosc. modcrn facilitics now used for working with plutonium. Things havc changed quitc dramatically with the goal of providing more protection for the workcr and morc complete containment of the plutonium within thc fiicility. The health protcction record of plutonium workers has k c n quitc good and 1 think it is clcar that if wc stick toourcontrolsand rcgulationsas rcgard plutonium, wcarc not destincd to rcpcat thc kinds ofthicgs that happcncd with thc usc of radium earlier in this century. ‘Table 2 shows the current status of scvcral LASL plutonium study groups. 1 S nwi caposcd during 1944-1945 42 men alwr cxpiwd rlirring M;inh;itltn I’rojCCr 25 Itwatcd ;riid rcapiiidcd IO yucxticinnaircs I90 cwly and current plutonium workers 175 identified hy Social Sccurity Numkr 2 idcntificd hy military x-rvicc numhcr Group 2, which is now in the early stagcs of study, will cxpand the size of the original cohort by pcrhaps 40 pcoplc. ’fwcnty-five of the 40 men who have been identified have been located and havc rcspondcd to questionnaires. Groups I and Oncc aguin. thesc are cxtremcly important subjects to study intensively as approximately thrce decides h a w clapscd sincc thcir cxposures. Group 3 will include a largcr spectrum of exposures including more recent accidents and cxposurcs to plutonium 238. All arc estimated to havc systemic plutonium burdens o f 4 or more nanocuries. -Fable 3 shows thc current systemic body

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Jrdcn cstimittcs bascd on urinc excretion for sonic ofthc mcn in thc Miintlnttan rojcct plutonium workcr group. Only those with niorc than thrcc maximum xmissihle body burdens (or 120 nCi) in 1972 arc shown. Again. the original cposures wcrc in thc carly 1940s so thiit Cast 3, who now liasapproxirniitcly IO mcs thc illlowtrblc occupational bonc burdcn. hiis carricd this estimated 4 IO nCi .plutonium for approximately t hrcc decades. Thc sclcctcd cases shown in l a b l e rcprcscnt systemic plutonium burdcns ranging from 0.13 l o 0.42 pCi, which rrrcspond to annual bonc doses of approximatcly 2 to 6 rad. 1 won't dwcll on .e csrlicr cstimatcs for 1953 and 1962 othcr than to point out that thcsc are tmcwhtrt unccrtain. Thc modcl that is uscd to estimate bQdy burdcn from the inc analysis data docs contain some uncertainty (13)and cannot bc applied -curatcly t o each individual. It is also truc that somc of the body burden timtrtcs arc based on relatively few data points. Tithie 4 contains information hich is dctailcd in an earlier publication (If]).Thc d;it;r iirc for the plutonium W-240 contcnt for somc tissucs that wcrc removed from Gisc 2 who dcvcloped mdition, which was found as part a l t h c medical follow-up study. affordcd an iportunity to obtain some hilmilrtoinil tissue. lyniph nodc tissue, rib tissuc and plutonium was approximately the Same in both L' tunior and normal lung tissuc. The lowest plutonium conccntrition was und in ii rib sample and thc highcst in the lymph nodc tissuc consistcnt with pcrinicntal findings in dogscxposcd to plutonium dioxide by inhalation. If one \uIiics a totill lung wcight of l000gr;ims.a rcspiratory lymph nodc wcight of 20 ams. and a homogeneous distribution of plutonium throughout these tissues, 2 total plutonium burdcn is itpproximatcly 8 nCi. roughly cqually divided ise 2. based on chcst counting proccdurcs, arc in rcasonablc agrccment (a :tor ofilbout 2) with the cstimatc bitscd on extrapolation from analysis of lung d lymph nodc tissue. From C;uc So. 2 in May I Y 7 1 Figure 2 is a photomicrograph oi';tn ;iutoradiograph olii plutonium particle I lyniph nodc scction rcmoved from Gisc 2 in May 197 I . Obscrvations of other tonium particles in the lymph nodc tissuc cxiimincd suggested ii vcry nonCorm radiation dose distribution from tlic plu[onium particles. Attcmpts have

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kcti made to estimate thc number of particles inhaled by the Manhattan Project plutonium workers. By making certain assunlptions for the mass median di;itnctcr, gcometric stitndard deviation of the distribution and the particle density, one can show that the mass fraction for plutonium dioxide particles largcr than 0.6 p m diarnetcr in thc distribution is approximately 15%. Further c-tlculations indicate that approximatcly lo' particles larger than 0.6 pm diamctcr could have becn rctained by thc 25 subjccts during their exposures in pcr particle. as suggcstcd by thc National Rcsources Defense Council Report men. 'fie observed lung cancer incidencc after almost 30 years since exposures is FIG. 2. Photomicrograph of an aulorJdiogrdph of a lymph node section rcmovcd from early PLUTONIUM ADMINISTRATION STUDlES IN HUMAN SUBJECTS In an attempt to dctcrminc relationships between urinary excretion, total cxcrction. and body content of plutonium. I 8 persons received plutonium parentally in 1945 and 1946 ( f 6 - f Q .Fifteen of the 18 were older than 45 years, ilnd all but two of the 182 I nwere given "'Pu only (onc received "'Pu and "'Pu and anothcr rcccived only Pu). The amounts of plutonium administered ranged ?

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.cup;itional maximunl pcrmissiblc body burdcn for '"Pu is 0.04 pCi. crc alive in November 1973. almost tlirccdccadcs after rccciving thc plutonium. xcrction data from somc of thc .survivors was prcscntcd carlicr at this hcck on the validity of the cxcrction data cquations that arc uscd currcntly by ddirrtion protectionists to cstimatc body burdens. It is of considerablc interest nilt much of the data uscd to cstablish thc excrction cquations came originally rom this group of 18 subjccts during thc rclativcly short timc (scvcral monthsin :lost CUSCS) they werc studicd. T o establish thc uniquc cxcretion curves, ;tnphitm uscd additional datii obtained over a fivc-month pcriod from three of tic plutonium rccipicnts and additional cxcretion data from scvcral Los Alamos ~xupiitionalcxposurc cases for about 300 days and onc for about 1700 days. I'hcsc rctcntion cquations havc provcd cxtrcmcly uscful for ovcr scvcral decades tiid appear to be somewhat conscrvativc in most instances whcn cstimatcd body jurdcns can be chcckcd with data obtained at postmoncm. Whcn initially cportcd in 1950 (16). Langham and coworkcrs statcd, "Admittedly the ibscrvations madc during this study providc no cvidcncc of w-hat may happen in 10-30 years. It may bc said. howcvcr, that thcse studics and those of other nvCstigiktors indicate that thc intravcnous injection of a singlc dose of 5 to 100 microgram d plutonium was without it C UtC subjcctivc or objcctivc clinical Onc of thc original 18 plutonium rccipicnts is of particular intcrest. Hc wasa whitc 58 ?car old male who was suffcring from gastric carcinoma and ?'vl)u as PUO:(NOJ)?by intravcnous injcction on 14 May 1945. Hc latcr received ;I total gastrectomy and a splenectomy but did not die until 9 January 1966, some 2 1 yc;irs latcr. from cardiovascular disease. Wc can obtain a vcry roughestimate of thc bonc dose by assuming 40% deposition in thc skeletal tissues with no subscquent loss. Under thcsc circumstanccs, the skelctal dose over the 21-year pcriod would bc approximately 900 rad. Thc annual dosc rate to the skeletal t issucs would bc approxirnrrtcly 4 0 rad, ;I factor of wpproximatcly 70 higher than

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the annual skeletal dose ratc of 0.6 rad delivcrcd by the maximum occupational bone burdcn of 40 nCi of "'Pu. During the summer of 1968, the United States Atomic Energy Commission authorized the establishment of the National Plutonium Registry which was later renamed as thc United States Transuranium Registry. The Registry is part of the organizational structure of the Hanford Environmental Health Foundation in Hanford, Washington, and functions as a repository for all pertinent available information thatmay be used to identify any radiation hazard to the worker that may cxist from exposure to transuranium elcmcnts (lY-2/). Major AEC contractors and some liccnsces using plutonium and other transuranium clcments have agreed to endorse thc program and to recommend that their affcctcd employees support this program. Cooperation with the USTR is cornpletcly voluntary on an individual basis and includes release of medical and health physics data. .Permission is also obtained on a voluntary basis for postmortem analyses of certain organs. The employees remain under the health physics and medical programs of the AEC contractor until termination of employment, at which time the USTR assumes responsibility if the employee has authorized postmortcm examination. . The major criterion used by the USTR to determine inclusion of an individual into the Registry is as follows: persons for whom the employer has provided a routine surveillance program because of a reasonable …