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

Perchlorate CHEMISTRY Highly Oxidized Chlorine, ClO 4 - 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

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

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

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. ”

Perchlorate TOXICOLOGY Before 1997 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 Children's Health and Chronic Effects Not Addressed High Uncertainties

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

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

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

Science Based Only, Not a Regulation RfD = What is a REFERENCE DOSE (RfD)? What is a REFERENCE DOSE (RfD)? DOSE is mg chemical per kg body wt. / day Uncertainty Factors Experimental Minimum

Toxicology EPA Interpretations From January 2002 Draft EPA Interpretations From January 2002 Draft Uncertainty Factors total 300-fold (Order of Magnitude=10 or ½ O.M. = 3) 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 This is NOT a very large Uncertainty Factor Interspecies (Animal-Human) 1X

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 Integrated Risk Information System EPA 2002 Draft TOXICITY SCHEDULE EPA 2002 Draft TOXICITY SCHEDULE

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

PERCHLORATE MANUFACTURERS and USERS MARCH, 2003

PERCHLORATE in the ENVIRONMENT 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 RELEASES REPORTED IN 25 STATES

PERCHLORATE RELEASES – March, 2003

Regulatory Authority (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 State Action Levels May Lead to Drinking Water Standards States and Tribes May Set Standards Not a Federally “Listed” Chemical

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

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 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

Comparative Risk Derivations “What if” calculation based on human data  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 mg/kg-day If a larger UF was applied for intrahuman variability then resultant estimate would be essentially equivalent to that proposed

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

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 Some Translocation and Concentration in Lettuce, Tobacco, Salt Cedar

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

Perchlorate Treatment ION EXCHANGE 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

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

Perchlorate Treatment INFORMATION Perchlorate Treatment INFORMATION U.S EPA Technology Innovation Office U.S EPA Technology Innovation Office American Water Works Assn Research American Water Works Assn Research Vendors May 2000 GWRTAC Technology Summary May 2000 GWRTAC Technology Summary