A Silver Nanotechnology Case Study
Total Page:16
File Type:pdf, Size:1020Kb
RISK ANALYSIS OF NANOTECHNOLOGY THROUGH EXPERT ELICITATION: A SILVER NANOTECHNOLOGY CASE STUDY _____________________________________ A Thesis Presented to the faculty of Engineering and Applied Sciences University of Virginia ____________________________________________________ In Partial Fulfillment of the requirements for the Degree Masters of Science Electrical Engineering by Emma Kathryn Fauss August 2008 ii APPROVAL SHEET The thesis is submitted in partial fulfillment of the requirements for the degree of Master of Science Electrical Engineering Emma Kathryn Fauss AUTHOR This thesis has been read and approved by the examining Committee: _________________________ Thesis Advisor _________________________ _________________________ Accepted for the School of Engineering and Applied Science: _________________________ Dean, School of Engineering and Applied Science August 2008 iii Abstract A practical approach is needed to analyze and assess quickly emerging technologies, such as nanotechnologies, where there exist uncertainty and undefined risk. The method presented here utilizes expert elicitation of a pre-selected panel of experts to determine Risk Triggers, which are essential in evaluating a technology, as well as to define exposure scenarios, knowledge gaps and regulatory issues. To illustrate this method, a case study was undertaken on silver nanotechnology in which the research team created a Silver Nanotechnology Consumer Inventory (SNCI), the interactional expert elicited a sample of eleven experts and the research team performed an analysis on the above-mentioned criteria. The interactional expert is key to oversee the elicitation process and the use of Trading Zones among various specializations. Overall this method proved to be very successful in assessing and analyzing the risk of an emerging technology because of the breadth of the expertise elicited, the expedited analysis and the ability to direct research funds where they will be most effective. iv Acknowledgements I would like to thank all the people who took time out of their busy schedules to contribute their expertise to this method and to all those who helped make this thesis possible. Thank you. v TABLE OF CONTENTS: ABSTRACT .......................................................................................................................................III ACKNOWLEDGEMENTS.............................................................................................................IV INTRODUCTION............................................................................................................................... 1 STATEMENT OF PURPOSE ................................................................................................................... 1 TECHNOLOGY NEEDS BETTER GUIDANCE....................................................................................... 1 SPEED OF TECHNOLOGICAL ADVANCEMENT IS INCREASING ....................................................... 2 A SOLUTION THOUGH ADAPTIVE MANAGEMENT & ANTICIPATORY GOVERNANCE................ 3 WHAT IS NANOTECHNOLOGY? .......................................................................................................... 5 UNIQUE PROPERTIES MAKE NANOTECHNOLOGIES HARD TO QUANTIFY ................................... 6 PUBLIC AWARENESS OF NANOTECHNOLOGY.................................................................................. 7 TYPE OF KNOWLEDGE ACCESSED THROUGH EXPERT ELICITATION .......................................... 8 DIFFICULTIES WITH EXPERT ELICITATION AND RISK ANALYSIS .............................................. 10 UNCERTAINTY ..................................................................................................................................... 10 BIAS...................................................................................................................................................... 11 HOLARCHY OF BELIEF TO OPINION.................................................................................................... 12 PARAMETERS TO CONTROL FOR BIAS IN EXPERT ELICITATION ...................................................... 14 RISK ASSESSMENT ............................................................................................................................. 15 SILVER NANOTECHNOLOGY, A CASE STUDY ................................................................................ 15 A BRIEF HISTORY OF SILVER ............................................................................................................. 15 TOXICOLOGY OF SILVER..................................................................................................................... 16 METHODS......................................................................................................................................... 22 CONTRIBUTION: THE SILVER NANO COMMERCIAL INVENTORY (SNCI) ................................. 23 ELICITATION ...................................................................................................................................... 29 PRE-ELICITATION ................................................................................................................................ 29 SELECTION OF THE EXPERTS .............................................................................................................. 31 THE INTERVIEWS ................................................................................................................................. 33 SYNTHESIS .......................................................................................................................................... 33 RANKING ............................................................................................................................................. 38 ANALYSIS ............................................................................................................................................ 41 RESULTS ........................................................................................................................................... 42 EXPOSURE SCENARIOS...................................................................................................................... 42 ABSORPTION (DERMAL) ...................................................................................................................... 44 INHALATION / ABSORPTION (LUNG) .................................................................................................. 45 INGESTION............................................................................................................................................ 46 NS RELEASE INTO AQUATIC ENVIRONMENTS.................................................................................... 47 NS MIGRATE THROUGH THE FOOD CHAIN ......................................................................................... 48 NS CHRONIC EXPOSURE...................................................................................................................... 49 RISK TRIGGERS.................................................................................................................................. 50 vi EXPOSURE RELATED RISK TRIGGERS ............................................................................................ 50 BIOAVAILABILITY ............................................................................................................................... 50 RATE OF AG+ RELEASE....................................................................................................................... 51 RATE OF AGGLOMERATION................................................................................................................. 52 COATING/MATRIX STABILITY ............................................................................................................ 53 MULTIPLE DISPOSAL PATHWAYS........................................................................................................ 53 EXPOSURE ROUTE DEPENDENT........................................................................................................... 54 HAZARD RELATED RISK TRIGGERS: MATERIAL PROPERTIES................................................... 55 PARTICLE SIZE & PARTICLE SHAPE.................................................................................................... 55 AGGREGATED NANOPARTICLES ......................................................................................................... 55 HAZARD-RELATED RISK TRIGGERS: MATERIAL REACTIVITY .................................................. 56 ANTIBACTERIAL ACTION .................................................................................................................... 58 CATALYTIC ACTION ............................................................................................................................ 59 AG+ RELEASE ...................................................................................................................................... 60 HAZARD RELATED RISK TRIGGERS: MATERIAL TOXICITY ....................................................... 61 DERMAL TOXICITY .............................................................................................................................. 61 TOXICITY IN LUNG............................................................................................................................... 62 TOXICITY FROM CHRONIC EXPOSURE ...............................................................................................