# 1 us army engineer research and development center multi-criteria decision analysis and...

#1US Army Engineer Research and Development Center

Multi-Criteria Decision Analysis and Environmental Risk Assessment for

Nanomaterials

Jeff Steevens and Elizabeth FergusonEnvironmental Laboratory

Engineering Research and Development CenterUS Army Corps of Engineers

Waterways Experiment Station, Vicksburg MS

Igor Linkov and Rick Pleus Intertox Inc.

83 Winchester Street Suite 1Brookline, MA [email protected]


Main Points

• Relation of pattern, structure-activity and physico-chemical properties of nanoparticles on toxicity and risk is widely unknown

• Challenges of risk assessment for situations with a limited knowledge base and high uncertainty and variability require coupling traditional risk assessment with multi-criteria decision analysis (MCDA) to support regulatory decision making

• Adaptive Management and Value of Information analysis (VOI) would provide a systematic tool for the dynamic linkage of Nanotechnology Risk Assessment and Risk Management with nanomaterial development goals as well as with new information on social and economic priorities


• Risk Assessment Challenges– Current risk assessment experience is for chemicals and stable

agents and not for engineered materials– Relation of pattern, structure-activity and physico-chemical

properties of nanoparticles on toxicity and risk is widely unknown– Uncertainty in exposure assessment, risk characterization and

dose-response is unprecedented

• Regulatory Challenges– Immediate regulatory need– Environmental evaluations and decisions are growing more

complex and current RA paradigm may not be appropriate

EPA Nanotechnology White Paper: Peer Review Panel Summary


• Model Uncertainty– Differences in model structure resulting

from: model objectives computational capabilities data availability knowledge and technical expertise of the

group– Can be addressed by

considering alternative model structures weighting and combining models Eliciting expert judgment

Problem: Model UncertaintyLinear Model

y = 3x - 0.6667

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4

X

Y

Polynomial Modely = 2x2 - 5x + 6

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4

X

Y

Mechanistic models for nanoparticle toxicity and exposure are very uncretain and expert judgement is required


• Parameter Uncertainty– Uncertainty and variability in

model parameters resulting from data availability expert judgment empirical distributions

– Can be addressed by Probabilistic Simulations (Monte-

Carlo) Analytical techniques (uncertainty

propagation) Expert estimates

Problem: Parameter Uncertainty

Nanomaterial properties are not well known, reported ranges are large and often unquantifiable

Mean+SDMean-SD

Mean+SEMean-SE

Mean

Oil and Grease in Sediment

Co

nc

en

tra

tio

n (

pp

m)

49

51

53

55

57

59

VAR1

VAR155.00050.00057.000


AD HOC Process

Quantitative? Qualitative?

Decision-Making Processes for Nanomaterial Risk Assessment and Regulation

Decision-Maker(s)

Include/Exclude?•Detailed/Vague?

•Certain/Uncertain?•Consensus/Fragmented?

• Iterative?• Rigid/unstructured?

Risk Analysis

Modeling / Monitoring

Stakeholders’ Opinion

Cost or BenefitsTools


Challenges to Complex Decision-making

• “Humans are quite bad at making complex, unaided decisions” (Slovic et al., 1977).

• Individuals respond to complex challenges by using intuition and/or personal experience to find the easiest solution.

• At best, groups can do about as well as a well-informed individuals if the group has some natural systems thinkers within it.

• Groups can devolve into entrenched positions resistant to compromise

• “There is a temptation to think that honesty and common sense will suffice” (IWR-Drought Study p.vi)


Risk Analysis

Modeling / Monitoring

Stakeholders’ Opinion

Cost

Decision Analytical Frameworks• Agency-relevant/Stakeholder-selected

• Currently available software•Variety of structuring techniques • Iteration/reflection encouraged

•Identify areas for discussion/compromise

Decision-Maker(s)

Sharing Data,Concepts and Opinions

Evolving Decision-Making Processes

Tool Integration

Decision Integration


Multi-Criteria Decision Analysis and Tools

• Multi-Criteria Decision Analysis (MCDA) methods:– Evolved as a response to the observed inability of people to

effectively analyze multiple streams of dissimilar information– Many different MCDA approaches based on different

theoretical foundations (or combinations)

• MCDA methods provide a means of integrating various inputs with stakeholder/technical expert values

• MCDA methods provide a means of communicating model/monitoring outputs for regulation, planning and stakeholder understanding

• Risk-based MCDA offers an approach for organizing and integrating varied types of information to perform rankings and to better inform decisions

Problems

Alternatives

Criteria

Weights

Synthesis

Decision

Decision Matrix

Evaluation

RA

MCDAFeedsRA

MCDARAFeedsMCDA

How can CRA, MCDA and AM improve the quality and

acceptability of decisions?

AdaptiveManagement


Case Study 1: Use of MCDA to Select the Best Nanomaterial

• Problem: Several nanomaterials have been identified for specific application with varying costs and benefits and potential risks

• Societal importance and public aceptability may be important for selection/prioritization decision


AHP : Case Study - Results


Case Study 2: Use of MCDA to Support Support Weight-of-evidence Evaluation for

Nanoparticle Toxicity

• Problem: Toxic effects of nanomaterials are uncertain. Multiple experimental studies are available that results in contradictory conclusions. Experimental studies have varying degree of scientific credibility and trust


Eco Risk Assessment: Assessment Endpoints


People:

Tools:

Process:

Policy Decision Maker(s)

Stakeholders (Public, Business, Interest groups)

Environmental Assessment/Modeling (Risk/Ecological/Environmental Assessment and Simulation Models)

Decision Analysis (Group Decision Making Techniques/Decision Methodologies and Software)

Scientists and Engineers

Summary: Essential Decision Ingredients

Define Problem &

Generate Alternatives

Gather value judgments on relative importance of the criteria

Identify criteria to compare alternatives

Screen/eliminate clearly inferior alternatives

Determine performance of alternatives for criteria

Rank/Select final alternative(s)


Main Points

• Relation of pattern, structure-activity and physico-chemical properties of nanoparticles on toxicity and risk is widely unknown

• Challenges of risk assessment for situations with a limited knowledge base and high uncertainty and variability require coupling traditional risk assessment with multi-criteria decision analysis (MCDA) to support regulatory decision making

• Adaptive Management and Value of Information analysis (VOI) would provide a systematic tool for the dynamic linkage of Nanotechnology Risk Assessment and Risk Management with nanomaterial development goals as well as with new information on social and economic priorities

# 1 us army engineer research and development center multi-criteria decision analysis and...

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