# Presentation: 721780

## Multi-Criteria Decision Analysis and 
Environmental Risk Assessment for Nanomaterials

**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 02446
- ilinkov@intertox.com

## 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**

## Slide 3

## EPA Nanotechnology White Paper: Peer Review Panel Summary

**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***

## Problem: Model Uncertainty

**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**

## Problem: Parameter Uncertainty

**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**

## Decision-Making Processes for Nanomaterial Risk Assessment and Regulation

**Decision-Making Processes for Nanomaterial Risk Assessment and Regulation**

- Decision-Maker(s)

- Include/Exclude?
- Detailed/Vague?
- Certain/Uncertain?
- Consensus/Fragmented?
-  Iterative?
-  Rigid/unstructured?

## 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)**

## Evolving Decision-Making Processes

- Decision-Maker(s)

***Evolving Decision-Making Processes***

## 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**

## RA

- Problems

- Alternatives

- Criteria

- Weights

- Synthesis

- Decision

- Decision Matrix

- Evaluation

- MCDA
- Feeds

- MCDA

- Feeds
- MCDA

***How can CRA, MCDA and AM improve the quality and acceptability of decisions?****** ***

- Adaptive
- Management

## 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

## Summary: Essential Decision Ingredients

***Summary: Essential Decision Ingredients***

## 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**