# 1 US Army Engineer Research and Development Center Multi-Criteria Decision Analysis and Environmental Risk Assessment for Nanomaterials Jeff Steevens and Elizabeth Ferguson Environmental Laboratory Engineering Research and Development Center US Army Corps of Engineers Waterways Experiment Station, Vicksburg MS Igor Linkov and Rick Pleus Intertox Inc. 83 Winchester Street Suite 1 Brookline, MA

# 2 US Army Engineer Research and Development Center 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

# 4 US Army Engineer Research and Development Center 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

# 5 US Army Engineer Research and Development Center 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 Uncertainty Mechanistic models for nanoparticle toxicity and exposure are very uncretain and expert judgement is required

# 6 US Army Engineer Research and Development Center 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

# 7 US Army Engineer Research and Development Center 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 Benefits Tools

# 8 US Army Engineer Research and Development Center 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)

# 9 US Army Engineer Research and Development Center 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

# 10 US Army Engineer Research and Development Center 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 MCDA Feeds RA MCDA RA Feeds MCDA How can CRA, MCDA and AM improve the quality and acceptability of decisions? Adaptive Management

# 12 US Army Engineer Research and Development Center 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

# 13 US Army Engineer Research and Development Center AHP : Case Study - Results

# 14 US Army Engineer Research and Development Center 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

# 15 US Army Engineer Research and Development Center Eco Risk Assessment: Assessment Endpoints

# 16 US Army Engineer Research and Development Center 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)

# 17 US Army Engineer Research and Development Center 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