Intro
Preface
Acknowledgment
Contents
List of Figures
About the Authors
1: Risk: Scope, Definitions, and Terminology
1.1 The Scope of Risk Assessment
1.2 Risk Management
1.3 Basic Definition of Risk
1.4 Describing Risks Using the Language of Probability
1.5 Categorizing Risks
1.5.1 "Incremental" Versus "Background" Risks
1.5.2 "Catastrophic" Versus "Chronic" Risk
1.6 Risk and Hazard
1.7 Relative Risk and Odds Ratio
1.7.1 Relative Risk
1.7.2 The Odds Ratio (OR)
1.7.3 Weakness in the Relative Risk and Odds Ratio

1.7.4 Understanding Confidence Intervals (CI)
1.8 Case Study 1: Driving or Flying?
Practice Exercises: Chapter 1
References
2: Probabilistic Risk Assessment
2.1 Risk and Uncertainty
2.2 Modeling Probability
2.3 Addition of Probabilities
2.4 Complementary Events
2.5 Multiplication of Probabilities
2.6 Conditional Probabilities
2.7 The Probability Tree
2.8 Using Frequencies or Probabilities
2.9 Order of Entering Variables Into the Tree
2.10 Probabilities Expressed in Disease Screening
2.10.1 Disease Screening Using Bayes' Theorem

2.10.2 Disease Screening Using Sensitivity and Specificity
2.11 When a Variable's Independence Is Missing or Uncertain
2.12 Calculation of "At Least One" Outcome (with Multiple Iterations)
2.13 Probabilities: A Summary
2.14 Case Study #2: Challenger Shuttle Disaster
Practice Exercises: Chapter 2
References
3: Quantitative Risk Assessment
3.1 Scope of Quantitative Risk Assessment
3.1.1 Long-Term Exposures
3.1.2 The Maximally Exposed Individual (MEI)
3.1.3 The Four-Step Assessment Model
3.2 Hazard Identification (Step 1)
3.2.1 Data from the Site

3.2.2 Assessing Carcinogens Versus Noncarcinogens
3.2.3 The US EPA IRIS Database
3.2.4 Changing Chemicals Over Time
3.2.5 Toxicity Scores
3.3 Dose-Response Assessment (Step Two)
3.3.1 Limited Human Data
3.3.2 Carcinogens and Noncarcinogens
3.3.3 Three-Step Model of Carcinogenesis
3.3.4 Threshold Models
3.3.5 Target Organs and Systems
3.3.6 "Dose" Versus "Dosage"
3.3.7 NOAEL/LOAEL
3.3.8 LD50
3.3.9 The Slope Factor for Carcinogens
3.3.10 Special Note About "Inhalation" and 'Fugitive Dust"
3.3.11 Sources of Toxicological Data

3.3.12 Safety Factors for Noncarcinogens (ADI, RfD)
3.4 Exposure Assessment (Step 3)
3.4.1 Components of the Pathway
3.4.2 The Migration/Movement of Substances
3.4.3 Identifying Exposed Individuals
3.4.4 Development of Exposure Scenarios
3.4.5 Exposure Point Concentrations
3.4.6 Bioconcentration Factor (BCF)
3.4.7 Incorporating Other Models
3.4.8 Dose Categories
3.4.9 Calculating the Chronic Daily Intake (CDI)
3.4.10 Helpful Hints in Preparing to Calculate Intake
3.4.11 Worked Intake Calculations
3.5 Risk Characterization [Step 4]