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.