2012/2013 Health Risk Limit
Rules Amendments
Nancy Rice, MPH
Kate Sande, MS
Minnesota Department of Health
August 28, 2012
Presentation Overview
 Rule Amendment history
 Health Based Guidance development process
– What is a HRL?
– How are guidance values derived?
 2012 Proposed Amendments
– New guidance
– Updated guidance
 Rule Amendment status
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History
 Groundwater Protection Act, 1989
– 1993/94 HRLs
 Health Standards Statute, 2001
 Additional legislation
– Water Levels Standard, 2007
– PFC expedited rule-making, 2007
 2008 HRL rule amendments (including
methodology changes), finalized 2009
 2010 HRL rule amendments, finalized 2011
 2012 HRL rule amendments, in process
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Proposed Rules
 6-Acetyl-1,1,2,4,4,7hexamethyltetraline
(AHTN)
 Carbamazepine
 Carbon tetrachloride
 1,2-Dichloroethane
 trans-1,2Dichloroethene
 N,N-Diethyl-metatoluamide (DEET)
1,4-Dioxane
Metribuzin
Naphthalene
1,2,4Trichlorobenzene
 1,2,3Trichloropropane
 Tris (2-chloroethyl)
phosphate (TCEP)



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Rule-eligible Guidance Values
 12 chemicals anticipated
 Health Based Guidance Values developed
during 2010 – 2011
 Chemical must have been detected in
groundwater
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Presentation Overview
 Rule Amendment history
 Health Based Guidance development process
– What is a HRL?
– How are guidance values derived?
 2012 Proposed Amendments
– New guidance
– Updated guidance
 Rule Amendment status
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Health-Based Guidance
 A health based guidance value, including a
Health Risk Limit (HRL), is the
concentration of a contaminant, or mixture
of contaminants, in groundwater that is
likely to pose little or no risk to human
health, including vulnerable
subpopulations, if consumed for one day or
up to a lifetime.
 Expressed as microgram (µg) of a
contaminant per liter (L) of water, shown as
µg /L
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MDH Health Based
Guidance
Risk
Assessment
Advice
(RAA)
No Rulemaking
Remains
RAA
Health
Based Value
(HBV)
Not In
Groundwater
(or other)
No Rulemaking
Remains
HBV
In
Groundwater
Rulemaking
Health Risk
Limit (HRL)
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Health Risk Assessment
 Water guidance developed by two
programs
– Health Risk Limit Program (HRL)
– Contaminants of Emerging Concern (CEC)
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HRL Priority Setting
 MDH
– Drinking Water Programs
– Site Assessment & Consultation
– Health Risk Assessment
 MPCA
– Ambient Monitoring Program
– Remediation Program
• Closed Landfill
• Petroleum
• RCRA
• Superfund
• Voluntary Investigation & Cleanup (VIC)
 MDA
– Incidence Response Program
– Pesticide Management Program
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HRLs in Context

If a non-cancer guidance value for a longer duration is
higher than the value for a shorter duration, the longer
duration value is set equal to the shorter duration value
Example:
⁻
⁻

MDH recommends a newer HBV or RAA over using an
older HRL
⁻

Calculated Short-term Value = 100 µg/L
Calculated Chronic Value = 200 ug/L, set to 100 µg/L
May result in dual guidance
MDH will replace older HBVs with promulgated HRLs
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Health Based Guidance
HRL (µg/L) ∝ (Toxicity) (Intake)
•Protective of sensitive life stages
(e.g., developmental stage)
•Evaluation of less-than-chronic
durations
•Identification of highly exposed populations
• Updated Intake Data
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Guidance Development
 Non-Cancer Durations  Health Standard
Statute Endpoints
– Acute (up to 24 hrs)
– Short-term (up to 30 days)
– Subchronic (up to 10% of a
lifetime)
– Chronic (>10% of a
lifetime)
 Cancer
–
–
–
–
–
–
Developmental
Reproductive
Immunological
Neurological
Endocrine
Cancer
– Usually based on lifetime
exposure, adjusted for
early life sensitivity
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Non Cancer HRL (nHRL)
nHRL duration [μg/L] = (RfD) x (RSC) x (Conversion Factor)
(IR duration)
RfD – Reference Dose (mg/kg-day)
RSC – Relative Source Contribution
Conversion Factor – 1000 (μg/mg)
IR – Ingestion Rate (L/kg-day)
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Cancer HRL (cHRL)
cHRL [μg/L] =
(1E-5) x (100 ug/mg)
[(SF x ADAF<2 yr x IR<2yr x 2) + (SF x ADAF2-<16 yr x IR2-<16yr x 14) + (SF x ADAF16+ yr x IR16+yr x 54)] / 70
SF – Slope Factor (mg/kg-day)-1
ADAF – Age Dependent Adjustment Factor
IR – Ingestion Rate (L/kg-day)
D – Duration for each age group
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Health Risk Assessments
 Three Levels of Review
– Primary
• Information compilation
• Data evaluation
• Qualitative/quantitative assessment
– Secondary
• Re-evaluation and assessment
• Discussion with primary reviewer
– Team Review
• Conclusions and rationale discussed
• Resolution of scientific judgment issues
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Presentation Overview
 Rule Amendment history
 Health Based Guidance development process
– What is a HRL?
– How are guidance values derived?
 2012 Proposed Amendments
– New guidance
– Updated guidance
 Rule Amendment status
17
New MDH Guidance
 6-Acetyl-1,1,2,4,4,7hexamethyltetraline
(AHTN or Tonalide)
 Carbamazepine
 N,N-Diethyl-metatoluamide (DEET)
 1,4-Dioxane
 1,2,4Trichlorobenzene
 Tris (2-chloroethyl)
phosphate (TCEP)
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Updated MDH Guidance
 Carbon tetrachloride
 1,2-Dichloroethane
 trans-1,2Dichloroethene
 Metribuzin
 Naphthalene
 1,2,3Trichloropropane
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Presentation Overview
 Rule Amendment history
 Health Based Guidance development process
– What is a HRL?
– How are guidance values derived?
 2012 Proposed Amendments
– New guidance
– Updated guidance
 Rule Amendment status
32
Rule Amendment Status
Governor’s Office
Preliminary Review
August
2012
Estimated October or
November 2012
Adopt Rules
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MDH Resources
 MDH Guidance Values Table (including links
to toxicological summaries)
http://www.health.state.mn.us/divs/eh/risk/guida
nce/gw/table.html
 2012 MDH Rule Amendment Information
http://www.health.state.mn.us/divs/eh/risk/rules/
water/rulerelated.html
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Questions?
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