Human Studies Project Team Fact Sheet: Los Alamos Involvement in the Studies of Plutonium

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Human Studies Project Team Fact Sheet Los Alamos March 17, I994 Los Alamos Involvement in the Huinan Studies of Plutonium Basis of Tolerance Animal Studies of As Los AIamos scientists used inctwmgly largu amount8 of plutonium in the Manhattan Project work of 1944 and 1945, thuy mgntzed that stria pncautions w m necessary to pmrm workm fiom tbis hazprdow subutace. However, no definitive information wm available thu could be ured to ertrblirh plutonium tolcrrnce limits for humans or to LMUU~Coccupmtid expormrrs. (Tolerance limit or dose was the terminology w d at rhat time.) In 194% the MPnhanaa Engineering Dlmict aurhariztd human studied for the collmioa of lhow imponant data In Janwy 1944, milligram quantities of plutonium were first delivered to Los Alamoo for ita work in the Maz~hamnProJon.At that tiroe, Project rcicntisb had proposed a tentative uafe tolaance limit of 5 micnrgnmr of h t d y deposited plutonium as a rmdard for PmjcEt aim. lEis tolerrplce I i t for plutonium wan bued on limits adopted for use in rhc radium dial-painting industries. By comparing the equivalmt radiation depositions of plutonium aod radium, rho MPnhartan Project's Mcdlcal Dlvision speculated &at plutonium w u onc-dftinh as toxic as radium, hence the S-microgram limit. Because of rho lack of knowledge about plutoniurn'r toxicity, animal metabolic studits were initiated in 1944 at rhra ManhattPn Roject 19boratoriex the Univenity of California Radiation Laboratory at Berkeley, the MetlUurgicll Laboratory at the University of Chicago, a d the University of Roches~erSchool of Medicine and These studies ahowed that plufanium deporitiom in the body (body burdens) could be dmrmined by mcamrriDQ the co0C;COVadOlU of plutonium in urine empier. The excretion mwdtl bared on lmimal data would be a mecuu to monitor workera for evidencc of plutonium ex porn. In JW 1944. data hrn the Chicago animrl studies r!m tho excretion rata for plutonium among the various types of laboratory 3id8wu id vy by as mudl as afsctor of 5, rad that humanr probably would daily excrete 0.01%of the plutonium retained An rrnimrl study a! Lor Alamor, authorized by Los Alambr Labonwry Dinctor J. Robm Oppenhelmer in Augua 1944, w u initlffcd beuuce Lor Alamor p d wanted a method to detect plutanium burdcna leos thtn 5 microgramr. Thcae studies * o w d that the peKmtag0 of plutonium excreted by rau wm indcpendenr of the total amount administered: ngardleri of the rize of the dore, the ~ercemageof thir informution as ddcal for evaluatiq m;topr~o~dwporunu to plutonium bawd 00 the analysie of urine sampler.

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Human Studies Project Team Fact Sheet By February 194% the 8nImd-derlveb 0.01% excntioII model had been used at Lor Alamor to atimatc plutonium burden8 for pcmmncl who were working with large amounts of plutonium. Urine analysis multo obtained in February and March 1945 suggested that some of the workas might have appmrched or exceeded a S-mi~rogramIeveI as larger quantifier of plutonium wen ptocard. In a letter dated March 29,1945, addfeued to Colonel Stafford Wamn, Director of rho Manhatlnn Disuict M o d i d Division at Oak Rldge, OppmWma pointed out that the hazuds of working with plutonium at L a Alamor were probably much more serious than were those at other Project sites. The risk usoclated with S-microgram dcpositiom and the uncertainty uroclrted with the animaldcrivd excretion rate were reasons for Oppenhtimn to endone a series of aalmal and humaa studfea aimed at protection for plutonium worken, The subsequent human plutonium injmion studice authorized by the Manham Engineering District involved 18 hocpitalizcd patfwr in four l d m : one patient at Oak Ridge. three patimu at the Univenity of Chicago, rhm patients at the Uni vd ty of Cdifwrnia, Berkeley, and e l m patiear at the Univenity of Roehnm School of Medicbe md The purpose of these studies W Y to provide dpla on the dcpositlon and excrdm of plutonium by hurmms, and pmvids a quantitative baais for detamhhq plwonium cxpoourcr to workers and crtablish criteria for removing penoancl from further exposure. Oak Rldge study. in AprIl 1945, Ihs Manhanrn Project's Medical Division. htadquanaed at Oak Ridge. Tennessa, arranged for a hoopitalizcd patient at Oak Ridge to be injected with a plutonium solution (thh sOlut!oz! w IU)K provided by Los Alamos). A sample of thi, solution, as well PI Urine, fed, and other biological s ~ ples, wu collected and shipped to Lor Alrmor for anriysis. The first aerier of wine r.mples were analyzed for their plutonium rcdvity 00. April 24, 1945. None of thcae biological samples remain at t o r Alamoa. L o a Alunos did not participate in thm studier. Fmm October 1945 to July 1946, eleven patlsW at the Udvmity of Rochcrnr School of Medlclns and DentisUy ucb W v e d one injection of a plutonium solution rupplled by Lo8 A l m s . Urine, fecal, and other biological samples

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wen sent to Lot Alamor for radiochemical analysis. None of these EUD ~ I W remain at Los Alamor. The re8ulU of there anrdieo w e n valuable to achtim In their efforu to find ways to m u r e protection for plutonium worken. Below are some of tbt Wings: 0 . The hj~cti~nof a ringle done of up to 100 mfcrogmmn of plutonium had no acute subjectin or objectiva clinical e&cu on the patients. , h with laborptory animala, rtre slrsletal aystcm w u the major site of An equation (the Laagham quadon) w u dcrivcd that deacribea the mion m e of plutonium u I functionof tima niter exposure. The biological half-life (the rime it t a b the body to eXQOtc half of its original plutonium deposition) w u estimwed 10 be about 118 y m . 'Ibe rcaults of these snrdies continue to play I -or role in nuclear health-monitoring activities. Today health physicbu atill rely on tbeac findings to cmima!e plutonium exporum and to auuzc radiafion protection for worken. The principal iiadinga of thm studies have been corrfinnad by evaluatio~~of Octuparioaally exposed workm. A classifid report (LA-11S1)011 the Rochhester studles wm prepared in 19SO by Wright Langham, who wm principal investigator for thi, mearch at Lor Namos. The lotonnation w u dcciasaified in May 1971 md republished in the 2Sth anniversary ~ p disme of HmWI Physics, Junc 1980. The mulu of tbe Rochester study have been dted in several open litetatux0 publicdons beginning in the latt During recent reviews of the Rocheater Tccocdl, tabulation mn w m noted in several set of dam. Thcsc crron did not n ign if i dy change the conclusions of the atudim or the health pmnction mcthoda derived from them. LALP-94-25 Loa A1pmw Invoivament in the Human S t d m of mutonium page 3