Document dQ9Dry0MpLeyyZn9G489bMKNB

nf 3M 3M Generst Offices . Swpeaen 1 5144100Fy _0700-13 73976995= AR 226226 - 0610 EFFEE ogy July 13,2000 Attn: TSCA Section 8() Coordinator Document Processing Center (7407) OfficeofPollution Prevention and Toxics U.S. Environmental Protection Agency 401 M Street, SW Washington, DC 20460 . . . : Re: TSCA Se Supplemental Submission, Docket Nos. 8EHQ-0373/0374 Dear Docket Coordinator: 3M is providing an interim report regarding the half-life of certain perfluorochemicals in human blood serum. New data suggest that the serum half-life of perfluorooctane sulfonate (PFOS) following cessationofoccupational exposure is likely = 10be four-fold lower than the 1000-1500 days previously suggested (median from 18 ~~ __ retireesIsnaomuprlepdaptehrreeenttiitmleeds "iPne1r8flmuoonrtoohcst=an2e7S0uldfaoynsa)t.e: Current Summary of Human ~~=9 23A82 fSerroam, tHheraelethretainrdeeTsorxeigcaorldoignyg Dthaetah,a"lfd-laitfeedofJaenluiamriyna2t1i,on19f9o9r,P3FMOSprfeoslelnotweidnglicmeistseadtdioantaof ~~ E=A occupational exposure. Based on those data, we estimated the half-life for PFOS at 1182 1575 days (between three and four years) following the cessationofoccupational = exposure. See also Olsen, et al. "Serum perfluorooctane sulfonate and hepatic and lipid clinical chemistry tests in fluorochemical production employees,J". Occup. Env. Med. 41:799-806 (1999) (estimating half-life for PFOS at 1000-1500 days); Ubel, et a., "Health statusofplant workers exposed to fluorochemicals: a preliminary report," Am. Ind. Hyg. Assoc. J. 41:584-589 (1980) (estimating halite for perfluorochemicals including perfluorooctanoic acid at 365-530 days). Since these reports, 3M has been conducting an expanded studyofthe half-life of PFOS and perfluorooctanoic acid (PFOA) in 27 retired perfluorochemical production workers. The study will run from 1999 to 2003, testing retirees' serum levels every six months. We have recently received the first Interim Report from this study. A copy is enclosed. FYI-80-201378 85000000029 / ee TSCASection 8(c) Coordinator Page20f2 To date, preliminary analyses from three serum collection periods utltizinag one-compartment model suggest that the serum half-life ofPFOS is likely to be four-fold lower than the 1000-1500 days previously suggested. The serum half-life for PFOA appears to be approximately one year, which is comparable to the estimate suggested by Ubel (1980). Becauseof the numberofsamples below the lower limitof quantitation for other fluorochemical analytes(including N-ethylperfluorooctanesulfonamideoacetate, N- methyl perfluorooctanesulfonamideoacetate, perfluorooctanesulfonamide, and perfluorooctanesulfonamideoacetate), or in the caseofperfluorohexanesulfonatebecause ofinconsistencies in measurements, additional collection periods are necessary before `half-life values can be calculated for thoseanalytes. Grertoivreeesp`l(Tawhnhutsorsfeeatri,erxesepesors(uuwmrhehoasissepberexiepmnoasraiunlrayeliytozepPdrFifOmoaSrr)tihlarynedteocfPoorlFlOteAwc)to.iocnolPplaeerrctitioicdoisnpapinentrsDieaocrdeastaiulnlrpCllooatnngtt.age term employees, averaging 28 yearsof service in the Decatur or Cottage Grove chemical dPiFviOsSiona.ndT0h.e1i1r0m3e.a1suprpemd fPoFr OPSFOsAe.rum concentrations ranged from 0.2 to 2 ppm for compartmental model was judged to have a good fit (+20.6), show a median senum half- Data from the retirees with at least three data points and for whom the linear one life for PFOS of 270 days (range 139-640) for 18 male retirees. The median serum halflife for PFOA was 344 days for 18 male and 2 female retirees. Serum half-lives were not associated with age, but the highest half-life calculations were for the two. female retirees in the study. Additional collection cycles will further refine these half-life estimates and take into account the retirees who were excluded from this interim report due to lack sufficient data or fit of the `one-compartment model. 3M will continue to apprise EPAofthe results ofthis ongoing study. Sincerely yours, 0 no Mn Staff Vice President & Medical Director Enclosure: 3M Medical Dept., Interim Report # 1, Determination of Serum Half-Livesof Several Perfluorochemicals, June 8, 2000