Perchlorate for Various Public Briefings - December, 2004,Sacramento

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PERCHLORATE

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

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EPAs 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
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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
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Typical Factors for Uncertainties
Serum Hormone Data Results

• 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
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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
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(No Transcript)
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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
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Thyroid Hormone Regulation
Hypothalamus
TRH
Pituitary
TSH
Brain
Thyroid
MIT DIT
T4, T3
I2 Tyrosine
I-
Proteolysis, T4, T3 release
I-
PCBs?
Deiodination
Ah-receptor Pb-like induction
T4
T3
I- Trapping
Organic Binding-coupling
Biliary Excretion
Perchlorate Thiocyanate Nitrate
PTU, Methimazole Sulfonamides Mancozeb,
Thiourea Aminotriazole
Thiram
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Human Clinical Data 200 ppb
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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.

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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.

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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
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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
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Ion Exchange San Gabriel Superfund Site Baldwin
Park, CA
Fluidized Bed Bioreactors at Aerojet Superfund
Site Rancho Cordova, CA
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Nevada - 1998
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Texas - 2002
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California - 2004