Office of Research and DevelopmentNational Center for Environmental Assessment
Human Health Risk Assessment and Information for SRP
July 28, 2009
Reeder Sams, Ph.D., Chief HPAGNational Center for Environmental Assessment
Office of Research and Development
Office of Research and DevelopmentNational Center for Environmental Assessment
Basic Principles of Risk Assessment at EPA
• The starting point for risk assessment is a critical analysis of available scientific information.
• Quantitative estimates of risk are, to the extent possible, Biologically-motivated, Data-driven.
• When there is insufficient data, default methods are used that Protect public health, Ensure scientific validity (i.e., scientifically plausible and extensively peer
reviewed), and Create an orderly and predictable process.
• Implementation of these principles involves extensive peer review.
Risk Assessment / Risk Management
Dose-Response Assessment
RiskCharacterization
ExposureAssessment
Hazard Identification
Risk Management
Decisions
PoliticalConsiderations
EconomicFactors
SocialFactors
Statutory and LegalConsiderations
Public HealthConsiderations
Risk Management
Options
Toxicity Testing
Risk AssessmentMethods, Models for Extrapolation
Research onExposure
Research on Mode of Action (TK/TD), dose-response, etc
Dose-Response Assessments
(IRIS,Criteria Docs); Communication, support
Guidelines forInterpretation
Data Generation
Data SynthesisAnd Modeling
Assessments
Application Risk Assessments
and Management
EPA Labs NCER
Others (e.g., NTP, NCI)
NCEA/RAF, NCER
NCEA
RegulatoryPrograms,Regions
Met
hods
, Mod
els,
Dat
aN
eeds
Research Assessment ApplicationResearch Assessment Application
5
Dose-response Assessment
RiskCharacterization
ExposureAssessment
Hazard Identification
Risk Management
Decisions
PoliticalConsiderations
EconomicFactors
SocialFactors
Statutory and LegalConsiderations
Public HealthConsiderations
Risk Management
Options
Human Health Assessment at EPA
NCEA occupies a critical position in EPA’s Office of Research andDevelopment between:
• the researchers in ORD labs who are generating new findings and data on human health
AND• the risk managers in the EPA program offices
and regions who must make regulatory, enforcement, and remedial action decisions
Office of Research and DevelopmentNational Center for Environmental Assessment
• Conducting human health risk assessments and management of the Agency’s Integrated Risk Information System (IRIS) (e.g., tetrachloroethylene [perc], methyl tertiary butyl ether [MTBE], methanol, trichloroethylene [TCE], acrylamide, inorganic arsenic and 72 others underway)
• Producing Integrated Science Assessments for air contaminants under Clean Air Act Ozone – completed March 2006 Lead – completed September 2006 Particulate Matter -- underway Nitrogen Oxides -- completed July 2008 Sulfur dioxide -- completed September 2008 Carbon Monoxide -- underway
NCEA’s Human Health Assessment work focuses on:
Office of Research and DevelopmentNational Center for Environmental Assessment
• Providing risk assessment research, methods, guidelines, training materials, and technical and regulatory support to EPA’s Program Offices and Regional Offices and the public Uncertainty analysis Identification of possible modes of action Physiologically-Based Pharmacokinetics (PBPK) Modeling Approaches to quantification Approaches for Assessing Risk of Environmental Exposures to
Age-Susceptible Populations (children, elderly) Less than Lifetime Assessments Approaches for cumulative risk assessment
NCEA:Human Health Assessment
(continued)
EPA’s Human Health Risk Assessment Tools• Integrated Risk Information System (IRIS)
• Exposure Factors Handbook
• Child-Specific Exposure Factors Handbook
• A Framework for Assessing Health Risk of Environmental Exposures to Children
• Approaches for the Application of Physiologically Based Pharmacokinetic (PBPK) Models and Supporting Data in Risk Assessment (Final Report)
• EPA’s Benchmark Dose Software (BMDS)
www.epa.gov/ncea
Office of Research and DevelopmentNational Center for Environmental Assessment
•Reference Dose (RfD)/Reference Concentration (RfC) for non-cancer effects
•Cancer risk: Hazard characterization, oral slope factors, and oral and inhalation unit risks
•Improvements in transparency, public participation, and consistency
•The new IRIS process was established on May 21, 2009
EPA’s Integrated Risk Information System
•IRIS provides qualitative and quantitative health effects information on over 540 substances
•Addresses chronic exposures
•Many high-profile, first applications of risk assessment guidelines and science policy
www.epa.gov/iris
Office of Research and DevelopmentNational Center for Environmental Assessment
Preparing for ChangeNAS/NRC Consultations
2007 Toxicity Testing in the 21st Century: A Vision and a Strategy
2007 Applications of Toxicogenomic Technologies to Predictive Toxicology and Risk Assessment
2008 Phthalates and Cumulative Risk Assessment
2008 Science and Decisions-Advancing Risk Assessment
2009 Toxicity Pathway-Based Risk Assessment: Preparing for Paradigm Change, May 11-13, 2009
Office of Research and DevelopmentNational Center for Environmental Assessment
Conclusions
• Human health risk assessment approaches are evolving in the presence of better understanding of biological mechanisms.
• Significant uncertainties remain and are being addressed.
• Questions remain about the direction of risk assessment.
• Challenges for risk assessors:
Evaluate when additional data are important for decision-making
Consider the scale of assessment
Integrate information from various paradigms
• Concepts of risk are changing, and continue to evolve.