PERCHLORATE

1. PERCHLORATE Kevin Mayer U.S. EPA, Region 9 Background and History Occurrence Toxicity Regulatory Status

2. Regulation Determination Whether or Not to Regulate Toxicity – Referred to National Academy Of Sciences for second Peer Review. Final 2004/05? Analytical Method– Improvements in progress by EPA and Commercial Labs Treatment Technologies – Full Scale Commercial Units Operating with Multiple Methods….COST Occurrence- National Data in 2004

3. EPA’s SCIENTIFIC PROCESS Final Reference Dose EPA Analysis External Peer Review DATA Increasing Complexity Over Time Provisional Reference Dose EPA Analysis Internal Review Only Third Tier Analysis Other Analysis (e.g.,World Health Org) External Review Process

4. What is a REFERENCE DOSE (RfD)? Science Based Only, Not a Regulation DOSE is mg Chemical per kg body wt. / day No or Lowest Observed Effect Level RfD= Uncertainty Factors

5. Serum Hormone Data Results Typical Factors for Uncertainties Human Differences: Sensitive Populations Animal Studies to Human Effects Short Term Studies to Long Term Effects Lowest-Observed-Effect-Level (LOAEL) to No-Observed-Effect-Level (NOAEL) Database deficiency Magnitude of 1, 3 or 10

6. Perchlorate TOXICOLOGY - 1992 Used as Human Drug Since 1950's Blocks Iodide Uptake into Thyroid, Disrupts Production of Hormones EPA Provisional Reference Dose 1992-95 4 to 18 ppb in Drinking Water No Data on Children's Health or Chronic Effects 1000x Uncertainty Factors

8. Perchlorate TOXICOLOGY - 2002 Studies from 1997 to 2001 Used to Measure Impact – Animal & Human EPA Focused on Sensitive Populations and Chronic Effects – Animal Studies Draft EPA Toxicity Assessment in 2002 Set RfD at 0.00003 mg/kg-day Drinking Water Equivalent = 1 ppb for Adults Only 300x Uncertainty Factors

9. Thyroid Hormone Regulation Positive Negative Liver PA T4, T3 PP-TH T4 T4-Gluc TTR/TBG UDPGTs Certain Tissues T4 T3 Deiodinases Hypothalamus TRH Pituitary TSH Brain Thyroid MIT DIT T4, T3 I- I2 + Tyrosine Proteolysis, T4, T3 release I- PCBs? Ah-receptor Pb-like induction Deiodination T4 T3 I- Trapping Organic Binding-coupling Biliary Excretion Perchlorate Thiocyanate Nitrate PTU, Methimazole Sulfonamides Mancozeb, Thiourea Aminotriazole Thiram

10. Human Clinical Data – 200 ppb

11. Perchlorate TOXICITY EPA Schedule January - June 2002 External Peer Review Expected Final Draft in Spring 2003 2003/04 National Research Council Review 2005 (approx.) Final Reference Dose on Integrated Risk Information System (IRIS)

12. Perchlorate REGULATORY STATUS NO Federal Standard. Only Site-Specific decisions under CERCLA, RCRA, SDWA As data gaps filled, perchlorate moves to the regulatory determination process EPA may make “off-cycle” regulatory determination when data become available -- rather than wait until next CCL regulatory determination in 2006 EPA may issue Health Advisory as a guidance in the interim, before a determination to regulate can be made.

13. The Regulatory Process MAXIMUM CONTAMINANT LEVEL (MCL) – Fully Enforceable Drinking Water Standard under SDWA EPA has 24 Months to Propose an MCL and an MCLG (non-enforceable MCL GOAL) Within 18 to 27 Months After the Proposal, EPA Must Publish a Final Rulemaking (MCL) Considerable Expert and Public Input Is Involved at Each Stage.

14. Perchlorate REGULATORY STATUS State and Tribal Advisory Levels Arizona… 14 ppb California… 6 ppb Massachusetts… 1 ppb Maryland… 1 ppb New Mexico… 1 ppb (monitoring only) New York… 5 ppb and 18 ppb Nevada… 18 ppb Texas… 4 ppb, 7 ppb or 10 ppb

15. Perchlorate TREATMENT TECHNOLOGIES Treatment Systems are Operating Full Scale, Commercially Available Ion Exchange – Regenerate or Dispose Various Types of Biological Systems Reverse Osmosis for Small Systems

16. Ion Exchange San Gabriel Superfund Site Baldwin Park, CA Fluidized Bed Bioreactors at Aerojet Superfund Site Rancho Cordova, CA

17. Nevada - 1998

18. Texas - 2002

19. California - 2004