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PERCHLORATE

PERCHLORATE. Kevin Mayer - U.S. EPA, Region 9 75 Hawthorne, San Fran. CA 94105 mayer.kevin@epa.gov. What is Perchlorate - Chemistry & Uses. Brief History of Environmental Concern. Toxicity. Occurrence. Regulatory Status. Perchlorate. CHEMISTRY. Highly Oxidized Chlorine, ClO 4 -.

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PERCHLORATE

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  1. PERCHLORATE Kevin Mayer - U.S. EPA, Region 9 75 Hawthorne, San Fran. CA 94105 mayer.kevin@epa.gov What is Perchlorate - Chemistry & Uses Brief History of Environmental Concern Toxicity Occurrence Regulatory Status

  2. Perchlorate CHEMISTRY Highly Oxidized Chlorine, ClO4- Dissociated Salt, Anion, in Water Highly Soluble, Mobile, Stable Difficult to Detect, Difficult to Treat Standard Ion Chromatography Method - Detection > 400 ppb - CA method to 4 ppb by March 1997

  3. USES of PERCHLORATE 90% used as Solid Rocket Fuel Oxidizer Explosives Fireworks and Pyrotechnics Reported in Nitrate Fertilizer from Chile

  4. PERCHLORATE HISTORY Before 1997 1980s - Aware of Perchlorate in CA and NV 1985-86 - San Gabriel Valley Superfund Site 1990s - Rancho Cordova (Aerojet) ppm 1992 and 1995 - Provisional Reference Dose 1997 - Analytical Breakthrough to 4 ppb

  5. Agency for Toxic Substances and Disease Registry - ATSDR (January 21, 1986 ): “… the data do not prove that perchlorate ion has actually been found.” . “The scientific database is insufficient to generate either an acute or longer-term health advisory for drinking water. ”

  6. Perchlorate TOXICOLOGY Before 1997 Thyroid Disruption (Iodide Mimic) Human Drug Tests in 1950's EPA Provisional Reference Dose 1992 / 95 Range of 4 to 18 ppb in Drinking Water Children's Health and Chronic Effects Not Addressed High Uncertainties

  7. Perchlorate Mode of Action Pituitary TSH Perchlorate THYROID GLAND Iodide T4 and T3

  8. Toxicology EPA Interpretations From January 2002 Draft mg/kg-day Draft Reference Dose of 0.00003 DW Exposure = 1 ppb Adult Effects in rat pups after dosing mothers Ecological Risks not Clear Other Routes of Exposure? Food?

  9. EPA 2002 Draft Effects on Lab Animals 0.01 mg/kg-day, lowest dose Thyroid hormones Brain morphometry Thyroid histopathology

  10. What is a REFERENCE DOSE (RfD)? Science Based Only, Not a Regulation DOSE is mgchemical per kgbody wt. / day Experimental Minimum RfD = Uncertainty Factors

  11. Toxicology EPA Interpretations From January 2002 Draft Uncertainty Factors total 300-fold (Order of Magnitude=10 or ½ O.M. = 3) Lowest Observed Adverse Effect Level 10X Sensitive Subpopulations (Intraspecies) 3X Duration (Lifetime exposures?) 3X Data Deficiencies (Immunotox.?) 3X Interspecies (Animal-Human) 1X This is NOT a very large Uncertainty Factor

  12. EPA 2002 Draft TOXICITY SCHEDULE January – June 2002 External Peer Review Spring 2003 Final Draft Internal Review 2003 ? National Academy of Science Review 2004 ? Revised Reference Dose on IRIS Integrated Risk Information System

  13. PERCHLORATE SHIPMENTS Primarily Manufacturer's Information Over 220 facilities 40+ States Most Information in Last 20 Years

  14. PERCHLORATE MANUFACTURERS and USERS MARCH, 2003

  15. PERCHLORATE in the ENVIRONMENT RELEASES REPORTED IN 25 STATES Alabama, Arizona, Arkansas, Colorado, Iowa, Kansas, Maryland, Missouri, Massachusetts, Minnesota, Nebraska, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, Texas, Utah, Virginia, Washington, West Virginia CALIFORNIA Over 5000 Water Supply Wells Tested Detected in 292 sources, 49 Wells over 18 ppb

  16. PERCHLORATE RELEASES – March, 2003

  17. Regulatory Authority Not a Federally “Listed” Chemical (SDWA, RCRA, CERCLA) Hazardous Material Characteristics Contaminant Candidate List (UCMR data) Possible EPA Health Advisory (OGWDW) State Action Levels May Lead to Drinking Water Standards States and Tribes May Set Standards

  18. Federal Drinking Water Standard Safe Drinking Water Act – Office of Water Drinking Water Data Collected through 2003 Decision to Regulate, Or Not – 2004 possibly Proposed MCL (MCLG) - 24 Months Final MCL – 18 to 24 Months later (2008?) A Public Policy Process – Public Comment Possible EPA Health Advisory (OGWDW )

  19. State “Advisories” California… 4 ppb New York… 5 ppb and 18 ppb Texas… 4 ppb, 7 ppb or 10 ppb Arizona… 14 ppb Massachusetts… 1 ppb Maryland… 1 ppb New Mexico… 1 ppb Nevada… 18 ppb

  20. Comparative Risk Derivations • “What if” calculation based on human data • 0.007 mg/kg-day • Uncertainty factor of 100 parceled as: • Intrahuman variability: 3 • LOAEL to NOAEL: 3 • Subchronic to chronic duration: 3 • Database insufficiency: 3 • Result is 0.00007 mg/kg-day • If a larger UF was applied for intrahuman • variability then resultant estimate would be essentially equivalent to that proposed

  21. Ecological Risks Direct Effects on Fish/Animals at High Concentrations Unknown Developmental Effects Concern for Arid Region Wetlands Agriculture Uses Colorado R. and GW Lettuce near Yuma / Crops along Colorado R. Imperial Valley/Coachella Valley Citrus in Riverside

  22. Ecological Risks Texas Tech Fish - Accumulated in Heads Texas Frogs - Developmental Effects Accumulation in Las Vegas Wash Rodents Plant Uptake Research – Not Definitive Some Translocation and Concentration in Lettuce, Tobacco, Salt Cedar

  23. Perchlorate Treatment Treatment Systems are Operating Full Scale, Commercially Available Ion Exchange Various Types of Biological Systems

  24. Perchlorate Treatment ION EXCHANGE Effective, Familiar Technology Accepted by State Regulators for Potable Water Resins Have Different Sorption/ Desorption Carbon – GAC – Not Effective Waste Brine, or Waste Resin

  25. Perchlorate Treatment BIOLOGICAL Similar or Identical to Nitrate Treatment Anoxic Environment Destroys Perchlorate to Cl and O Must Add a Bacteria Growth Substrate, BOD

  26. Perchlorate Treatment INFORMATION U.S EPA Technology Innovation Office www.clu-in.org/perchlorate American Water Works Assn Research www.awwarf.com/research/spperch.asp May 2000 GWRTAC Technology Summary www.frtr.gov/perchlorate Vendors

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