A more efficient and effective testing and assessment paradigm for chemical risk management
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A More Efficient and Effective Testing and Assessment Paradigm for Chemical Risk Management. Edward O denkirchen , Ph.D. Office of Pesticide Programs US Environmental Protection Agency. Business Case: Pesticide Risk Management. Mission Statement –

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A more efficient and effective testing and assessment paradigm for chemical risk management

A More Efficient and Effective Testing and Assessment Paradigm for Chemical Risk Management

Edward Odenkirchen, Ph.D.

Office of Pesticide Programs

US Environmental Protection Agency


Business case pesticide risk management

Business Case: Pesticide Risk Management

Mission Statement –

  • Best possible regulatory decisions to protect public health and environment.

  • Rely on all best available scientific information.

  • External Peer-Review; Public Participation.

    Goal – Timely & targeted credible information to inform decisions.

Time & Cost

Benefit

  • Benefits:

  • Resource Savings

  • Efficiency

  • Increase Reliability

  • Public Trust


Challenges for risk assessment

Challenges for Risk Assessment

Risk Management Tools

Risk Assessment Capability & Capacity

Scientific & Technological Advancement


Common risk management needs

Common Risk Management Needs

Ecological & Human Health Risk Assessment

  • Transparency & trust in decision-making.

  • Resource demands: Effectiveness and efficiency.

  • Spatial, temporal & biological decision scales.

  • Integration of multiple stressors: Chemical and Non-Chemical.


2009 nrc science decisions

2009 NRC Science & Decisions

The committee encourages EPA to focus greater attention on design in the formative stages of risk assessment, specifically on planning and scoping and problem formulation, as articulated in EPA guidance for ecologic and cumulative risk assessment (EPA 1998, 2003).


A more efficient and effective testing and assessment paradigm for chemical risk management

Characterization of Exposure

Characterization of Ecological Effects

Communicating Results to the Risk Manager

Risk Management

Ecological Risk Assessment

Planning (Risk Assessor/ Risk Manager Dialogue)

PROBLEM FORMULATION

A

N

A

L

Y

S

I

S

RISK CHARACTERIZATION


A more efficient and effective testing and assessment paradigm for chemical risk management

PROBLEM FORMULATION

ANALYSIS

RISK CHARACTERIZATION

PROBLEM FORMULATION

Integrate Available Information

Source and Exposure Characteristics

Ecosystem Potentially at Risk

Ecological Effects

Planning (Risk Assessor/ Risk Manager Dialogue)

As Necessary: Acquire Data, Iterate Process, Monitor Results

Assessment Endpoints

Conceptual Model

Analysis Plan

ANALYSIS


A more efficient and effective testing and assessment paradigm for chemical risk management

2007 NRC Toxicity Testing in 21st Century: A Vision and Strategy


Nrc 2007 toxicity testing in the 21st century a vision strategy

NRC 2007 “Toxicity Testing in the 21st Century: A Vision & Strategy”

Objective:

Foster transformative paradigm shift based largely on increased use of in vitro andin silicosystems that will:

Broaden coverage of chemicals, endpoints, life stages.

Reduce cost and time of testing, increase efficiency and flexibility.

Use fewer animals.

Provide more robust data using mode of action and dosimetry information.


Enhanced integrated approaches to testing and assessment

Enhanced Integrated Approaches to Testing and Assessment

Combine existing exposure and toxicity data including information from new technologies (in silico, in vitro and –omics) to:

  • Formulate hypotheses about the toxicity potential of a chemical or a chemical category.

  • Target further data needs specific to a chemical or members of a chemical category for a given exposure.

Progressive, Tiered-Evaluation Approach: “Integrate, Formulate, Target”


A more efficient and effective testing and assessment paradigm for chemical risk management

Adverse Outcome Pathways – definition and example

Paradigm Shift in Toxicology: Pathway-based assessment to predict adversity.

Exposure

Uptake-Delivery to Target Tissues

Perturbation

“Normal”

Biological

Function

Biologic

inputs

Cell injury, Inability to regulate

Adverse

Outcomes

(e.g., Mortality,

Reproductive

Impairment)

Chemical

Chemical Extrapolation

Cellular response pathway

Early cellular

changes

Adaptive

Responses

Species Extrapolation

Adverse outcome

relevant to

risk assessment

Molecular

initiating event

Perturbed cellular

response pathway

Chemical & Non- Chemical Stressors

Modified From NRC 2007


Spatial temporal and biological scales

Spatial, Temporal and Biological Scales

Integration of Scales:

Source to Outcome


Watersheds with drinking water intakes

Watersheds with Drinking Water Intakes


Adverse outcome pathway

In vivo studies

Structure Activity Relationships

In vitro studies

Communities within landscapes

Molecular Target

Cellular Response

Chemicals

Pharmaco- kinetics

Tissue Organ

Population

Individual

Monitoring

Adverse Outcome Pathway

Toxicity Pathways

Molecular

initiating event

Key events or predictive

relationships spanning

levels of biological

organization

Adverse outcome

relevant to

risk assessment

Greater Toxicological Understanding

Greater Risk Relevance


A more efficient and effective testing and assessment paradigm for chemical risk management

NAS Review of Ecological Risk Assessments Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act (ESA)

Examining scientific and technical issues related to methods and assumptions used by EPA, FWS, and NOAA to carry out joint responsibilities under the ESA and FIFRA.


Nas review of ecological risk assessments under fifra and esa

NAS Review of Ecological Risk Assessments Under FIFRA and ESA

Charge Questions - Topic Areas:

  • Best Available Scientific Data & Information

  • Geospatial Information and Datasets

  • Mixtures

  • Sub-lethal, Indirect, and Cumulative Effects

  • Models

  • Interpretation of Uncertainty


A more efficient and effective testing and assessment paradigm for chemical risk management

Habitat-Species Response

Habitat/Biota Distribution Data Layers

Demographic Data

Life History

Data

Spatial Models

Population Models

Chemical Data Layers

Species Physiology Data

Chemical, Species Dose-Response Data & Models

Building Capacity for Explicit Risk Assessments

OUTCOME:

Efficient-effective site-specific risk assessment


Moving forward back to the future

Moving Forward – “Back to the Future”

  • The technology may be “new”, but the logic for advancing the science to change risk assessment and risk management is not.

OECD Principles for QSAR Validation:Transparency & Utility for a Specified Application

  • Predicted endpoint is defined.

  • Mechanistic interpretation associated with predictions, if possible.

  • Defined chemical domain of applicability for the model.

  • Appropriate measures of goodness of fit, robustness, ability to predict.

  • An unambiguous algorithm.


Challenges to accelerate risk assessment in the 21st century

Challenges to Accelerate Risk Assessment in the 21st Century

Overall objectives are monumental.

  • Incremental steps; identify opportunities for success; focus on tangible applications (categories, read across, priority setting).

    Building libraries of information will take time.

  • Effective use of information technology can help accelerate AOP discovery, development, and evaluation.

    Establishing linkages depicted in AOPs.

  • Support transition from qualitative to quantitative uses; species and chemical extrapolations.

    Establishing linkages across toxicology (human health and ecology).

  • Multi-talented individuals and teams.

    Continuum of learning and refining.


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