Document DRQbNEgkmnmOE7OR6jm4L01a
L arry R. Zobel, M D . M PH Staff Vice President and M edical Director
3M M edical D epartm ent
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3M Center, B uilding 220-2E -02 PO Box 33220 St. Paul, M N 55133-3220 651 733 5181 Office 651 733 5152 Fax
3M
May 24, 2001
AR226-1030A002
Document Processing Center (7407) Attn: Section 8(e) Coordinator Office of Toxic Substances USEPA 401 M Street, SW Washington, DC 20460
TSCA 8(e) SUBSTANTIAL RISK NOTICE: potassium perfluorooctanesulfonate (CASRN 2795-39-3)
Dear 8(e) Coordinator:
3M has received a draft statistical report from Covance Laboratories in connection with a two-year dietary study of potassium perfluorooctanesulfonate (PFOS) in rats. The final report for this study is in preparation; however, the data from the statistical report are believed to represent information which meet the reporting threshold for section 8(e) of TSCA.
In the study design, male and female rats were assigned to a control group or one of five dosed groups that received PFOS mixed into their feed. The dietary dose levels were 0.5, 2, 5, and 20 parts per million (ppm) plus an additional "recovery" group at 20 ppm for which dosing ended at one year and the rats were allowed to recover through the end of the study.
The attached table summarizes the relevant findings. When the final report on this study becomes available, it will be submitted to the EPA. The findings of statistical significance presented in the attached table are not meant, in and of themselves, to imply biological significance. These data will be interpreted for biological significance in the final report.
A considerable body of toxicity information on PFOS can be found in EPA docket AR-226. PFOS has been subjected to numerous assays for genotoxicity. The results of those assays show a lack of genotoxicity.
Please contact me for further information.
Regards,
PPi^^P
Larry KTZobel, MD MPH Staff Vice President & Medical Director
c: Dr. Charles Auer Dr. Oscar Hernandez
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TABLE: RESULTS OF STATISTICAL ANALYSIS OF SELECTED NEOPLASTIC LESIONS FROM TWO-YEAR DIETARY STUDY OF PFOS IN RATS.
' FEMALES
Tumor Hepatocellular Adenoma Hepatocellular Carcinoma
Historical Control(a) 4/394(1.0%) (0 % --4.3 %) 0/394 (0 %)
Control
0/60 (0 %) trend*(b)
0/60 (0 %)
0.5 ppm 1/50 (2.0 %) 0/50 (0 %)
2 ppm 1/49 (2.0%) 0/49 (0 %)
5 ppm 1/50 (2.0 %) 0/50 (0 %)
20 ppm 5/60 (8.3 %)* 1/60(1.7%)
20 ppm Ree 2/40 (5.0 %) 0/40 (0 %)
Hepatocellular Adenoma & Carcinoma
NA (0 % - 4.3 %)
0/60 (0 %) trend**
1/50 (2.0 %)
1/49 (2.0 %)
1/50 (2.0 %) 6/60 (10.0 %)* 2/40 (5.0 %)
MALES
Tumor
Hepatocellular Adenoma
Pancreatic Islet Cell Carcinoma
Thyroid Follicular-Cell Adenoma
Thyroid Follicular-Cell Carcinoma
Thyroid Follicular-Cell Adenoma & Carcinoma
Historical Control
6/393 (1.5 %) (0 % - 3.3 %)
5/390 (1.3 %) (0 % - 4.8 %) 17/391 (4.3 %) (0 % - 11.3 %) 4/391 (1.0%) (0 % - 3.2 %)
NA (0 % - 14.5 %)
Control
0/60 (0 %) trend*
0/60 (0 %) trend*
3/60 (0 %)
3/60 (5.0 %)
6/60(10.0%)
0.5 ppm
3/50 (6.0 %)
2/49 (4.1 %) p = 0.1793 5/49 (10.2 %)
1/49 (2.0 %)
6/49 (12.3 %)
2 ppm
3/50 (6.0 %)
1/50 (2.0 %) NA
4/50 (8.0 %)
1/50 (2.0 %)
5/50 (10.0 %)
5 ppm
20 ppm
1/50 (2.0 %) 7/60(11.7%)*
4/50 (8.0 %) p = 0.2148 4/49 (8.2 %)
5/50(10.0%) p = 0.0463* 4/59 (6.8 %)
2/49 (4.1 %)
1/59(1.7%)
5/49 (10.2 %) 5/59 (8.5 %)
20 ppm Ree
0/40 (0%)*(c)
3/40 (7.5 %)
9/39 (23.1 %)*(d) 1/39(2.6%)
10/39 (25.6%)*lc)
* denotes statistical significance at p < 0.05 ** denotes statistical significance at p < 0.01
a) Data from six prior two-year studies with Sprague - Dawley rats in the same laboratory. b) The significance indications in the control column are one-tailed for trend. c) For high-dose recovery values, the significance is for one-tailed, pair-wise comparison to the high-dose group. d) For high-dose recovery values, the significance is for one-tailed, pair-wise comparison to the control and high-dose group.
