Exposure Assessment and Safety Considerations for Working with Engineered Nanoparticles

Michael Ellenbecker, Emeritus Professor of Occupational and Environmental Hygiene and Director of the Toxics Use Reduction Institute at the University of Massachusetts Lowell, has published widely on the measurement and control of airborne contaminants.  He is co-author of the Wiley textbook Ventilation for Control of the Work Environment, 2d edition.  For the past ten years he has led the nanoparticle health and safety efforts at UMass Lowell. Candace Tsai, Assistant Professor of Occupational Health and Industrial Hygiene at Purdue University, and previously Manager for EHS research at UMass Lowell, has led groundbreaking research in exposure assessment and engineering controls associated with nanotechnology development.  She received her doctorate in occupational and environmental hygiene and cleaner production at UMass Lowell.  Dr. Tsai also has Master’s degrees in chemical engineering and management science of business administration.  Dr. Tsai has evaluated the potential for nanoparticle exposure in laboratories at many universities and  private companies, and developed control techniques and strategies to eliminate exposure in more than a dozen of them.

• Preface xiii1 Introduction 11.1 Why A Book on Nanotechnology Health and Safety? 11.2 Some Scenarios 31.3 Organization of the Material 51.4 Our Approach to Nanoparticle Health and Safety 5References 72 What is a Nanoparticle? 82.1 Nanotechnology, Nanomaterials, and Nanoparticles 92.1.1 Nanotechnology 92.1.2 Nanomaterial 92.1.3 Nanoparticle 92.2 Naturally Occurring Nanoparticles 102.3 Industrial Nanoparticles 122.4 Engineered Nanoparticles 142.4.1 Carbon Nanotubes 152.4.2 Fullerenes 172.4.3 Quantum Dots 172.5 Emerging Uses for Engineered Nanoparticles 192.6 Other Useful Definitions 202.6.1 Aerosol 202.6.2 Particle Inertia 212.6.3 Brownian Motion 222.6.4 Particle Diameter 232.6.5 Agglomerate versus Aggregate 242.7 Summary 25References 263 Why are we Concerned? The Unique Properties of Nanoparticles 283.1 Surface]to]Volume Ratio 283.2 Particle Size 303.3 Particle Concentration 323.4 Dose Metrics: Particle Number, Surface Area, Morphology, and Surface Properties 333.5 Implications for the Occupational and Environmental Health Impacts of Nanoparticles 333.5.1 Respiratory Deposition 333.5.2 Skin Penetration 343.6 Implications for Physical Risks 353.6.1 Introduction 353.6.2 Current Status 353.6.3 Conclusions 363.7 Summary 37References 374 Routes of Exposure for Engineered Nanoparticles 394.1 Introduction 394.2 Engineered Nanoparticle Exposure through Inhalation 404.2.1 Human Respiratory System 404.2.2 Particle Deposition in the Respiratory System 434.3 Engineered Nanoparticle Exposure Through Dermal Contact 464.4 Engineered Nanoparticle Exposure Through Ingestion 484.5 T ranslocation of Nanoparticles from the Lung 484.6 Summary 49References 495 Current Knowledge on the Toxicity of Nanoparticles 515.1 Introduction 515.2 The Toxicity of Industrial Nanoparticles 525.3 Nanoparticle Toxicity: General Concepts 535.3.1 Routes of Exposure 535.3.2 In Vivo and In Vitro Testing 535.4 Carbon Nanotubes 545.5 Fullerenes 565.6 Quantum Dots 585.7 Metal]Based Nanoparticles 585.8 Summary 59References 606 Sources of Exposure 636.1 Overview of Occupational Exposures 636.2 Occupational Exposures in Research Facilities 646.3 Occupational Exposures in Manufacturing Facilities 656.4 Exposure Potential for ENPs in Different Physical States 666.4.1 Dry Powders 666.4.2 Liquid Suspensions 696.4.3 ENPs Bound to a Solid 726.5 Environmental Exposures to Engineered Nanoparticles 736.5.1 Environmental Releases 736.5.2 Exposures Through a Product’s Life Cycle 74References 767 Evaluation of Exposures to Engineered Nanoparticles 797.1 Current Knowledge Concerning Exposure to EngineeredNanoparticles 797.2 Exposure to Engineered Nanoparticles by Inhalation 817.2.1 Mass Sampling 817.2.2 Surface Area Measurement 837.2.3 Number Concentration Measurement 847.2.4 Conversion between Number, Surface Area, and Mass Concentrations 987.2.5 Particle Characterization 997.3 Dermal Exposures to Engineered Nanoparticles 1027.4 Evaluation of Exposures in Aquatic Environments 1047.4.1 Introduction 1047.4.2 Sample Collection 1047.4.3 Measurement Methods 1057.4.4 Exposure Characterization in Aquatic Environments 107References 1088 Exposure Characterization 1128.1 Exposure Characterization Steps 1138.1.1 Standard Occupational Hygiene Models 1138.1.2 Exposure Characterization for Nanomaterials 1138.2 Exposure Measurement Strategies 1208.2.1 Single]Location Measurement 1208.2.2 Multiple]Location Measurement 1208.2.3 Near]Field and Far]Field Measurement 1218.2.4 Dynamic Personal Sampling Measurement 1228.3 Data Analysis and Interpretation 1238.4 Statistical Analysis of Data 1248.4.1 Pearson Correlation 1248.4.2 T]test 1258.5 Practical Aspects of Aerosol Sampling and Microscopy Techniques 1278.5.1 Aerosol Sampling Techniques 1278.5.2 Microscopy Techniques 1288.6 Practical Applications and Limitations 1288.6.1 Particle Losses 1288.6.2 Concentration Measurement versus Particle Samples 1308.7 Typical Production Processes 1308.7.1 Synthesis of Carbon Nanotubes 1308.7.2 Composite Manufacture 1318.8 Case Study: Manual Handling of Nanoparticles 1338.8.1 Materials and Conditions 1348.8.2 Particle Handling 1348.8.3 Measurements 1348.8.4 Aerosol Particle Characterization 1368.8.5 Results 1378.8.6 Discussion 1448.8.7 The Challenge and Brainstorming 1458.8.8 Study Questions 1458.9 Case Study: Synthesis of Carbon Nanotubes 1468.9.1 Materials and Synthesis 1468.9.2 Measurement 1478.9.3 Results 1488.9.4 The Challenge and Brainstorming 1558.9.5 Study Questions 1568.10 Case Study: Exposure From Twin Screw Extrusion Compounding 1568.10.1 Materials and Production Process 1578.10.2 Measurements 1588.10.3 Results 1588.10.4 The Challenge and Brainstorming 1628.10.5 Study Questions 163References 1649 Control of Occupational Exposures to Engineered Nanoparticles 1669.1 Control of Airborne Exposures 1669.1.1 General 1669.1.2 Laboratory Fume Hoods 1699.1.3 Alternatives to Conventional Fume Hoods 1789.2 Control of Dermal Exposures 1819.2.1 General 1819.2.2 Clothing and Personal Protective Equipment 1819.3 Administrative Controls and Good Work Practices 1829.3.1 Housekeeping 1839.3.2 Work Practices 1839.3.3 Worker Training 1839.4 Respiratory Protection 1859.4.1 General Considerations 1859.4.2 Respirator Designs 1869.5 Case Study: Comparison of the Performance of Various Fume Hoods 1959.5.1 Materials and Hoods 1959.5.2 Measurements 1989.5.3 Results 1989.5.4 The Challenge and Brainstorming 2069.5.5 Study Questions 2069.6 Case Study: Performance of Nontraditional Fume Hoods 2069.6.1 Materials and Hoods 2079.6.2 Measurements 2079.6.3 Results 2079.6.4 The Challenge and Brainstorming 2149.6.5 Study Questions 215References 21510 Control of Environmental Exposures 21910.1 Control of Air Emissions 21910.1.1 Factors Affecting Air Cleaner Performance 22010.1.2 Categories of Air Cleaning Devices 22010.2 Control of Water Emissions 22810.3 Nanoparticles in Solid Waste 23210.4 Control of Exposures Throughout a Product’s Life Cycle 23310.5 Uncertainties and Needed Research 23410.6 Case Study—Filtration Control 23410.6.1 Materials and Process 23510.6.2 The Challenge and Brainstorming 24610.6.3 Study Questions 246References 24711 The Regulatory Environment for Engineered Nanomaterials 24911.1 Occupational Health Regulations 25011.1.1 Occupational Health Regulations in the European Union 25011.1.2 US Occupational Health Regulations 25211.1.3 Summary: Occupational Exposure Regulations 25611.2 Environmental Regulations 25711.2.1 US Environmental Regulations 25711.2.2 Environmental Regulations in the European Union 26111.3 Comparison of Nanotechnology Regulation under TSCA and REACH 26311.3.1 The Precautionary Principle and the Burden of Proof 26311.3.2 Differences in Handling New and Existing Chemicals 26411.3.3 Volume]Based Thresholds and Exemptions 26511.4 Private Law 26511.5 Conclusions 266References 26612 Future Directions in Engineered Nanoparticle Health and Safety 26912.1 Where we are Today 26912.1.1 Research Efforts in the United States 26912.1.2 Research Efforts in Europe 27312.1.3 Progress toward Research Goals 27312.2 Human Health Effects Studies 27612.3 Exposure Assessment 27612.3.1 Future Needs in Exposure Assessment Techniques 27612.3.2 The Development of Occupational Exposure Limits 27812.4 Optimal Approaches to Control Exposures 27912.4.1 Engineering Control of Occupational Exposures 27912.4.2 Control Banding 28012.4.3 Respiratory Protection 28012.4.4 Safe Work Practices 28112.4.5 Air Pollution Control of Nanoparticles 28112.4.6 Water Pollution Control of Nanoparticles 28112.4.7 Nanoparticles in Waste Streams 28212.5 The Future of Regulation 28212.6 Conclusions 282References 283Index 285