Document jBg4Q18XwkDVgBrxeXV8oqoE2

Co . IM Genera Offices SSehpcaanes sstaton FY1-050]-1378 Wi PR tac; k #R 226 -10.20 3M April 25.2001 FYI-0H -8013n 78 2 Te i= . E==r --E=--=8 E==8 = E==5 =u OMfrf.icCehaorflePsolAluuteiron Prevention and Toxics U.S. Environmental Protection Agency 4W0a1shMingSttroene,t DS.WC. 20460 Contain no ce => ~= Re: Serum Half-Life of Perfluorooctane Sulfonate Dear Mr. Auer "wTihtihs wyiolul,sOusmcmaarrHiezrentahnededzi,scMuiscsihoanelduSrainntgoroourancodnmfeerernecgearcdailnlgonneMwaricnfhor1m9a,t2i0o0n1 obrained as part of the ongoing serum half-life study on PFOS. Asuslfyoonuatken(oPwF,O3S)Mihnassebreuemnofartetteimrpetdinwgortkoecrasl.culWatee haahvaelf-plriefveiofuorslpyerrfelpuoorrtoeodcotanntewo diinftfeirciumltdtaotainsteetrsp.ret3.MThhaesycdonotinontuecdortroosbtourdaytethoiusripsrsiueo.r cCaulcrurleanttiloyns.available data are IhnalJfalniufearfyor1P99F9O,S3iMn prertoivrieddewdorEkPerAs'wistehrluimmoiftedapdpartoaxifmraotmel3ywo1r,k4e0r0sdaiynsd.ica3tiMnghaad oinnpsreorguremshsalaf llairegerofstPuFdyO.SanadmoonngJu2l7y r1e5t,ir2e0d0e0m,plsouybemeist.tedThtehesefiersmtpilnotyeeriemsrheapdort worked at 3M's Decatur. Alabama and Cottage Grove, Minnesota manufacturing plans. +2 ax M"Tahiys i1n9it9i9alaanndalNyosivseomfbtehre 129799re,tdireeseisgunsateedddtast,atypoainndtst.colUlsecitneadgionnNco-vcoemmpbaerrtm1e9n9t8, mdaoydsel(,atnhgeem1e3a9n se6r4u0mdahyasl)f.lifTehdeetreermmaiinniendgfo9re1m8polfotyheees27eiethmeprlhoaydeelseswsatsha3n0t3hree duasta ipnoiitnatlslyorredipdonneodt sfohrocwynaotmreonld.gusThperi3m0a3tedsa(y2s7w4adsayns)e.ar tAhletsoeurguhm whaelfwelirfee that awareof several limitations in this study. 3M considered the interim data to be an ivamrpyrionvgeamneanltytoicvetreochunripqrueevsiofoursdeestteirmamtien,inbgasPeFdOSo.n onHloywe3veemrp,lothyeeeIsn,tearnidm uRseipnogrt advised caution in interpreting the limited data set. 33-7751 =so ~*~ SreetruurmnedwassevceorlallecmtoendtihnsMlaatyer2a0n0d0sfhoorwefdourretsuhldtastianpcoonisnits(t1e)n.t wIinitthiatlhaonsaelyexspiescwteads. Tanhailsytciacusteedchunsiqtuoereexehxiabmitisnevoarfisaboiulrictyeosoff2e0rrtoor3i0n%thwehleanbotrhaetosraymmeesaasmuprleemeinst. The 2 Mr. Charles Auer April 25,2001 Page 2 `measured at different all samples from one time points. The best way subject during one analytic to reduce this run. Random variability is to run errors represent another type of error, and multiple analysisofthe same sample can be used to reduce errors from this source. Nine of the 27 subjects, representing a range of PFOS values, were selected for rseaamnpalleyssisf.or Teraicphliscuabtjeeacntawlyesries awnaaslydzoendedfuorrianlgl otniemeanpaoliynttisc(rtount.hrIonugthhits;)w.ayA,ll controllable sourcesofvariability were reduced. Preliminary analysis of these data does not corroborate the range for serumhalf life reported in the first Interim Report. The data from these nine subjects fortothrough t; suggesat minimum half life near 1500 days, but we are still exploring various issues that confound interpretationofthe data. Ointchleurdefatchteorpsocssoimbplleicparteisnegncaesosfeostsmheenrtfolfutohreocsheemriucmalhaslff-rloifme oicncrueptaitrieodnwaolrekxeprossumrae.y tehxaptomsuarye bdeurmientgabthoeliszteuddyt;ooPrFdOifSfidcuulrtiyngdetrhievisntgudayv;eornaggoeivnaglnuoens-iofctchuepaetliimoinnaaltion Kvianreytiincgs laerveelcso.ncAetnttrhaitsipooni-ndte,ptehnedecnatu,tisoinncaedtmhoeniwsorhkeedrisnbbeogtahn3tMh'esstInutdeyrwiimtRheport and the October 2000 draft OECD Initial Assessmentis appropriate. Neither the current calculation nor prior values should be considered conclusive `estimates. We plan to submit that, however, is to a second interim report in collect data for a periodof the at summerof2001. Our plan after least two years and possibly longer before doing any more analysis, which will then be done in such a way as to reduce laboratory variability as much as possible. Although this typeof study continues to carry many limitations, it remains a good `opportunity to measure human serum half life, albeit at concentrations `many times `higher than those observed in non-occupationally exposed individuals. Please do not hesitate to contact meifyou have any questions. Very truly yours, Sony Rpbet Mo, mk Je Larry Rl Zobef, M.D. M.P.H. Medical Director Mr. Oscar Hemandes Mr. Michael Santoro