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Superfund Advisory Committee January 23, 2014

Tetrachloroethylene: Cancer Risk Values. Superfund Advisory Committee January 23, 2014. Sandra Baird, Ph.D. Office of Research and Standards. Road Map. Brief History. 2012 US EPA final based on liver tumors Derived values for leukemia and liver 2008 MassDEP based on leukemia and liver

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Superfund Advisory Committee January 23, 2014

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  1. Tetrachloroethylene: Cancer Risk Values Superfund Advisory Committee January 23, 2014 Sandra Baird, Ph.D. Office of Research and Standards

  2. Road Map

  3. Brief History 2012 US EPA final based on liver tumors Derived values for leukemia and liver • 2008 MassDEP based on leukemia and liver • 2008 US EPA draft based on leukemia • 2010 NRC Review lacked consensus on leukemia • 2011 US EPA Interagency draft based on leukemia

  4. Why did we review PCE? • Basis of US EPA 2012 value different from • MassDEP’s 2008 and 1990 • US EPA 2008 and 2011 • NRC Committee did not reach consensus • US EPA 2012 two IURs >10-fold different • US EPA 2012 liver-based IUR differed substantially from US EPA 2008 liver and leukemia-based IUR

  5. ORS Process • Review recent data, primary literature, models • MassDEP Health Effects Advisory Committee • Authors of US EPA Harmonized PBPK model • Address concerns from NRC & interested parties • High leukemia background rate • Dose response • NTP data • Relevance to humans • Up to date PBPK model

  6. Decisions • US EPA harmonized PBPK model should be used • JISA 1993 bioassay should be used not NTP 1986 • Leukemia data should be used to derive PCE cancer risk values • Total metabolized PCE should be used for interspecies extrapolation instead of total PCE

  7. Leukemia Endpoint • Background rate high but… • Treated animal rate higher • Earlier and more severe in treated animals • Statistically significant dose-response NTP & JISA • No data to rule out relevance to humans

  8. Derivation • JISA 1993 (0, 50, 200, 600 ppm) • Males and Female Rats • Harmonized PBPK model • Total Metabolized Dose

  9. Cancer Risk Values • Inhalation and oral values are based on same extrapolation from inhalation studies • Inhalation unit risk (IUR) 3 x 10-6 per ug/m3 • Oral cancer slope factor (CSF) 2 x 10-2 per mg/kg/day

  10. Method 3 Short-Form

  11. Proposed Target Indoor Air Concentration and GW-2 Standard DEP pre-2008 Tox Value DEP 2014 Tox Value 15 GW-2 = 50 ug/L GW-2 = 20 ug/L 11 11 10 Indoor Air Concentration (ug/m3) 4 4 5 0.2 0.04 Risk Conc. Back- ground Target Air Conc. Target Air Conc. Risk Conc. Back- ground

  12. Thank You! More information on tetrachloroethylene cancer risk values will be posted on MassDEP Chemical page http://www.mass.gov/eea/agencies/massdep/toxics/sources/chemical-research-and-standards.html Questions? Comments? Sandra.Baird@state.ma.us 617-654-6587

  13. Proposed Target Indoor Air Concentration and GW-2 Standard DEP pre-2008 Tox Value DEP 2014 Tox Value US EPA 2012 Tox Value GW-2 = 50 ug/L GW-2 = 20 ug/L GW-2 = 30 ug/L 15 11 11 10 7.8 8 Indoor Air Concentration (ug/m3) 5 4 4 4 0.2 0.04 Risk Conc. Back- ground Target Air Conc. Target Air Conc. Target Air Conc. Risk Conc. Back- ground Risk Conc. Back- ground

  14. Method 3 Short-Form

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