Health Risk Assessment for Asbestos and Other Fibrous Minerals

Andrey Korchevskiy, PhD, DABT, CIH is a biologist, mathematician, certified toxicologist, and certified industrial hygienist. He is the Director of Research and Development at Chemistry & Industrial Hygiene, Inc. James Rasmuson, PhD, CIH, DABT, and AIHA Fellow, is the founder and senior scientist at Chemistry & Industrial Hygiene, Inc. Eric Rasmuson, MS, MHS, DABT, CIH is the President/CEO of Chemistry & Industrial Hygiene, Inc.

List of Contributors xv

Preface xvii

Part I Hazard Identification 1

1 Mineralogical Characteristics and Risk Assessment of Elongate Mineral Particles (EMPs): Asbestos, Fiber, and Fragment 3
Ann G. Wylie

Introduction 3

Nomenclature 6

Source Specificity: Chemical and Physical Properties 8

Source Specificity: Dimension 11

Structural Groupings of Common Elongate Minerals 13

Establishing the Chemical Composition of Minerals 15

Mineral Intergrowths and Associations 16

Bioreactivity of Mineral Surfaces: Chemical Factors 17

The Specificity of Mineral Surfaces: The Example of Quartz 17

General Considerations of Solubility 18

Formation of Reactive Oxygen Species (ROS) 20

Coatings 21

Surface Charge 22

EMP Surfaces: Chain Silicates and Zeolites 23

Physical Factors 24

Specific Surface Area 24

Enthalpy and Other Thermodynamic Properties 26

Density and Aerodynamic Diameter 26

Stiffness and Tensile Strength 28

The Effects of Heat 30

Dimensionality: General Considerations 30

Establishing Measurement Protocols 32

Optical vs. Electron Microscopy Methods 32

Stratified Counting 34

Sample Preparation for TEM: Direct vs. Indirect Preparation 34

Frequency Distributions of Length and Width 35

Lung Burden 37

Dimensionality and Carcinogenicity 38

Discussion 39

References 40

2 Toxicology of Mineral Fibers and Implications for Risk Assessment 52
Brooke T. Mossman

Introduction 52

Use of Rodent Models to Analyze the Toxicity to Disease Potential of Naturally Occurring and Synthetic Fibers 53

Inhalation Studies 53

Intratracheal Instillation and Oropharyngeal Aspiration Studies 54

Intrapleural Injection Studies 54

Intraperitoneal Injection Studies 54

Comparative Results on Effects of Asbestos and Other Naturally Occurring Fibers in Rodent Studies 54

In vitro Models of Toxicity 66

Advantages and Disadvantage of In vitro Models 66

Contributions of In vitro Models to Understanding Mechanisms of Cytotoxicity and Carcinogenesis by Mineral Fibers 67

Properties of Mineral Fibers Important in Toxicity and Carcinogenic Effects 68

A Systems Biology Approach to Understanding Connections and Interactions Between Adverse Outcomes in Mineral Fiber-Induced Diseases 71

References 72

3 Health Outcomes of Asbestos Exposure – A Pathology and Diagnostic Perspective 82
Bruce Case

Introduction 82

Nonmalignant Change in Structure or Function 83

Nonmalignant Asbestos-Related Disease 84

Pleural 84

Asbestos Effusion 84

Pleural Plaques and Localized Pleural Thickening (LPT) 84

Diffuse Pleural Thickening 88

Rounded Atelectasis 89

Lung 89

Asbestosis 89

Malignant Diseases Attributable to Asbestos Exposure 92

General Comments 92

Asbestos-Related Lung Cancer 94

Mesothelioma – Accelerating Knowledge 96

References 102

Part II Exposure Assessment 109

4 Principles of Exposure Assessment for Elongate Mineral Particles (EMPs) 111
Eric Rasmuson, James Rasmuson, and Andrey Korchevskiy

General Principles and Methods 113

Gathering Information 113

Evaluating the Quality of Data 114

Measurement Techniques 116

Comparison of the Results of Different Analytical Methodologies 120

Proximity to the Emission Source 121

Adjusting Results for Censored Data 122

Correlation of EMP Exposures and Lung Burden Analysis 122

References 123

5 Asbestos Exposure Measurements: Principles of Current and Historical Data Interpretation 127
Garry Burdett

Aim and Background 127

Causes of Asbestos-Related Lung Disease and Their Relationship to Exposure Assessment 128

Exposure Measurement 130

Historic Methods of Asbestos Exposure Measurement 131

Gravimetric Methods 131

Impaction Sampling and Microscopic Particle Counting 132

Impinger Sampling and Microscopic Particle Counting 132

Thermal Precipitator (TP) Sampling and Microscopic Particle Counting 133

Direct Reading Instruments for Particle and Fiber Counting 134

Early Sampling Strategies 135

Development of the Current Analytical Methods for Fiber Counting 136

Membrane Filter Sampling and Phase Contrast Microscopy Fiber Counting (MF-PCM) 136

Membrane Filter Sampling and Electron Microscopy (EM) Analysis 137

Limitations of Current Indices of Exposure Assessment 139

Variability of the MF-PCM Index Over Time 140

Sampling Method 140

Sample Preparation 141

Microscope Equipment and Set-Up 142

Fiber Definition 143

Counting Procedures and Performance 144

Effect of Changes to the MF-PCM Counts Over Time 145

Conclusion 146

Acknowledgements 147

References 147

6 Asbestos Exposure Modeling Using Advanced Tools Including Computational Fluid Dynamics (CFD) 153
Daniel Hall, James Rasmuson, and Cassidy Strode

Introduction 153

Validation and Application of CFD Air Dispersion Modeling 155

Overview of CFD General Methodology 157

CFD Simulation Set-Up 159

Geometry Creation and Set-Up 159

Mesh Creation 160

Parameter Set-Up 160

Computational Solve 162

Post-processing 162

Complementary Modeling Software Tools 163

Other Software Tools 164

Indoor and Outdoor Modeling Examples 164

First Example – Indoor CFD Modeling 164

Preliminary Outdoor CFD Wind Simulation – Effect on Indoor Ventilation 166

Indoor CFD Simulations 168

Mill Ventilation 168

Other Model Parameters 169

Source Descriptions 170

Reheat Furnace Brick Removal Source 170

Pipe Insulation Removal Source 171

CFD Results 172

Second Example – Outdoor CFD, AERMOD, and CALPUFF Models 174

Model Geometry 177

Receptor Descriptions 177

Source Descriptions 177

Fugitive Plant Emission – Manufacturing, Finishing, Fiber Warehouse, Tray Loading, and Stripping Station 180

Baghouse Source Emission Rates 182

Pipe Storage and Shipping Yard Source Emission Rate 183

Crusher Source Emission Rate 183

Meteorology 184

CFD Results 186

EPA Outdoor Dispersion Models 188

Geophysical Set-Up 188

CALMET Set-Up 189

CALPUFF Processor 189

CALPUFF Results 191

AERMOD Model 191

Geophysical Set-Up 191

Meteorology Set-Up 191

AERMOD Set-Up 193

AERMOD Results 194

Comparison of CFD, CALPUFF, and AERMOD Results 194

Discussion and Conclusions 194

References 197

Part III Dose-Response Assessment 201

7 Asbestos Dose–Response Assessment: The Peto Model and Its Application in the US EPA and Berman and Crump Studies 203
Andrey Korchevskiy

Rationale and Meaning of the Peto Model 203

Utilization of the Peto Model by the US EPA 212

Berman and Crump Meta-analysis Based on Peto Model 218

References 228

8 The Hodgson and Darnton Approach to Quantifying the Risks of Mesothelioma and Lung Cancer in Relation to Asbestos Exposure 233
Lucy Darnton

Introduction 233

Overview of the Hodgson and Darnton Approach 234

Metrics and Data Requirements 235

Lung Cancer 235

Mesothelioma 236

Other Data Issues 236

Summary of Cohorts Included in the Original and Updated Meta-Analyses 237

Crocidolite Cohorts 238

Amosite Cohorts 239

Other Amphiboles: Vermiculite Miners and Associated Workers, Libby, Montana, USA 241

Chrysotile Cohorts 242

Summary of Original and Updated Meta-Analyses 245

Mesothelioma 245

Lung Cancer 250

Nonlinear Exposure–Response Relationship 256

Pleural Mesothelioma 257

Peritoneal Mesothelioma 259

Lung Cancer 260

Summary 262

Application of Hodgson and Darnton for Risk Assessment 262

Conclusions 264

References 266

9 Prediction of Mesothelioma Mortality in the Context of Country-wide Risk Evaluation 270
Lucy Darnton

Conclusions 284

References 284

10 Implications of Exposure Measurement Methodologies for Dose–Response Assessment in Asbestos Worker Cohorts 286
Garry Burdett

Electron Microscopy Fiber Size Distribution for Different Cohorts and Their Relationship to PCM Fiber Counts 287

TEM Fiber-Size-Distribution in Cohorts from Mines and Mills 288

TEM Size Distributions from Manufacturing Cohorts 289

SEM Size Distributions from Manufacturing Cohorts 292

EM Determinations of Asbestos Fiber Types in Asbestos Industry Cohorts 293

Natural Occurrence 294

Mixed-Use 295

External Sources 296

Lung Burden Analysis 296

Conversions of Historic Cohort Measurement Indices to MF-PCM Fiber Counts 296

Conversion from Impinger Counts to MF-PCM 297

Conversions from Other Particle Counting Methods 299

Conversions from Gravimetric Measurement 299

Crocidolite Cohort Exposures 302

Wittenoom Occupational 302

Wittenoom Environmental 305

South African Mines and Mills 306

Massachusetts Cigarette Filter Manufacturing 309

UK Gas Mask Workers 310

Other Cohorts Exposed to Crocidolite 311

Crocidolite Summary 311

Amosite Cohort Exposures 311

South African Amosite Mining 311

Patterson, New Jersey 314

Tyler, Texas 315

Uxbridge 315

Amosite Summary 316

Chrysotile Mining and Milling Cohort Exposures 317

Quebec, Canada 318

Balangero, Italy 318

Qinghai, China 319

Uralasbest, Russia 321

Chrysotile Mining Summary 322

Chrysotile Textiles 322

South Carolina Textile Workers 324

North Carolina Textile Workers 325

Chongqing Chrysotile Cohort 327

Chrysotile Textiles Summary 328

Other Chrysotile Cohorts 328

Discussion and Outlook 330

Acknowledgement 333

References 333

11 Mathematical Modeling of Cancer Potency for Various Fibrous Minerals 344
Andrey Korchevskiy, James Rasmuson, and Eric Rasmuson

References 360

12 Theoretical and Practical Aspects of Asbestos Dose–Response Assessment 366
Andrey Korchevskiy and James Rasmuson

General Considerations and Model of Asbestos Dose–Response Assessment 366

Linear Model 367

Nonlinear Model 368

Relationship Between Different Estimation of Mesothelioma and Lung Cancer Potency Factors 371

Life Tables and Life Expectancy of the Exposed Population 374

Linearity and Nonlinearity of the Dose–Response Curves 375

Threshold and Benchmark Dose Response in Asbestos Risk Assessment 376

Community and Occupational Risk Assessment 378

Peritoneal Mesothelioma 378

Other Types of Cancer 380

Inhalation Unit Risk (IUR) for Asbestos Fibers 383

Asbestos Dose–Response and Tobacco Smoking 385

Other Factors Impacting the Dose–Response Relationship for Elongate Mineral Particles 387

References 388

Part IV Risk Characterization 393

13 Risk Characterization for Occupational and Environmental Exposure to Asbestos: Case Studies 395
James Rasmuson, Andrey Korchevskiy, and Eric Rasmuson

References 408

14 Asbestos in Soil: Risk Characterization for Occupational and Environmental Exposures 412
Andrey Korchevskiy and Robert Strode

References 424

15 Asbestos in Brakes: Risk Assessment for Exposure Patterns with Nonlinear Dynamics 427
Andrey Korchevskiy, Robert Strode, and Arseniy Korchevskiy

Ambient Air Emissions from the Brakes in Street Canyons 428

Fibers in Car Brakes: Chaotic Behavior of Emissions in a Self-regulated Community 433

Diagnosing the Chaotic Trends 439

References 441

Index 443