Document 2qn9n6d92KOpyBmz8a3pY9D2p

~ p. 1 Katherine E . Reed, Ph .D . 3M Environmental, Health and 900 Bush Avenue . Building 42-2E-26 Staff Vice President Safety Operations PO Box 3333 1 St . Paul, MN 55133-3331 ~~ ~k 4~ o ~S7 .' . ... ~~~ ~ r7o 7- , ~ 651 778 433 1 Certified Mail June 6, 2007 Document Processing Center EPA East - Room 6428 Attn : Section 8(e) CO NTA I N NO CB1 O ffice of Pollution Prevention and Toxics US EP A 1200 Pennsylvania Avenue Washington DC 20460-000 N1 W ~~Iill ~i ~'~il~ I! i ilI II~i I~III ~Ii~I II~II iilll ~~~,I~I III NO CBI Re : TSCA 8(e) Substantial Risk Notice : Supplemental to Docket No . 8EHQ-0598-373 ; Sulfonate-based and Carboxylic-based Fluorochemicals To whom it may concern : 3M recently received a draft final report from an oral (gavage) developmental neurotoxicity and thyroid function study in rats conducted on potassium perfluorooctane sulfonate (PFOS) . The objective of this study was to determine the potential of PFOS to induce neurotoxic effects in offspring following exposure of the mother to PFOS during gestation and lactation, and to determine the effects of exposure on mate rnal and neonatal thyroid status . Exposure to PFOS during gestation and lactation did not result in any neurotoxic effect in Fl-generation offspring at doses of 0 .1 or 0 .3 mg/kg/day and showed at the highest dose of 1 .0 mg/kg/day only a very limited, transient effect on motor activity and habituation in males . Time-mated female rats were administered potassium PFOS daily by oral gavage at dose levels of 0 .1, 0 .3, or 1 .0 mg/kg/day during gestation and through lactation day (LD) 20 . Functional obse rv ation battery (FOB), acoustic startle response, locomotor activity, and lea rn ing and memo ry evaluations were performed . In addition, brain weight and potential neuropathologica l evaluations were conducted, and indicators of physical development (balanopreputial separation and vaginal patency) were evaluated . Thyroid structure and function were evaluated via microscopic examination of thyroids, thyroid cell proliferation assay, and analysis of TSH levels . Functional obse rv ational batte ry parameters, start le responsiveness, swimming ability, learning and memo ry and mean age and weight at attainment of balanopreputial separation and vaginal patency in the F , males and females during the pre- and/or post-weaning periods were unaffected by mate rnal treatment with PFOS . In addition, there were no PFOS-related clinical or inte rn al findings or changes in brain weight, length, or width in F , males or females . PFOS-related effects were limited to postnatal day (PND) 17, where an increase in total and ambulato ry motor activity counts and a decrease in the number of rats habituating to the test environment were obse rv ed in males in the 1 .0 mg/kg/day group as compared to the concurrent control group . There were no other test article-related effects on motor activity in either sex at any dosage level on PND 13, 17, 21 or 61 . There were no changes in TSH or thyroid gland histology that were att ributable to PFOS . Matern al body weights were decreased with statistical significance in the p. 2 1 .0 mg/kg/day dosage group relative to controls during the lactation period . This indicates that the highest dose chosen was appropriately effective in producing an effect in mate rn al rats . Although these data do not meet the `substantial risk' repo rt ing threshold, we recognize the ongoing work by U .S . EPA to assess fluorochemicals . Therefore, we are placing these results in the 8(e) docket as a supplement to previous submissions . The in-life po rt ion of this study is complete and a draft fi nal report has been produced . The fi nal report is pending inclusion of results from analysis of pharmacokinetic samples . The final report will be forwarded to the EPA once it is received . If you have any questions or need additional information, please contact Deanna Luebker at (651) 737-1374 . Sincerely, ~-- ~~'~~~~~ ~ . ~~~fe~ Katherine E . Ree d Staff Vice President, Environmental, Health and Safety Operations