Contents Figures .................................................................................................................................................................................. vi Tables ................................................................................................................................................................................... vii Objectives ............................................................................................................................................................................ viii Audience ............................................................................................................................................................................. viii Acknowledgments ................................................................................................................................................................. ix PART 1: BASIC CONCEPTS IN ENVIRONMENTAL HEALTH RISK ASSESSMENT ..................................................... 1 Chapter 1: Introduction to environmental health risk assessment .................................................................................................... 3 1.1 What is risk assessment? ............................................................................................................................................ 3 1.2 When to undertake risk assessment ........................................................................................................................... 4 1.3 Types of risk assessment ............................................................................................................................................ 5 1.4 The distinction between risk assessment and risk management .................................................................................. 6 1.5 Evaluating risk assessment methods ........................................................................................................................... 6 1.6 Risk assessment models and formats ......................................................................................................................... 7 1.7 The five stages of environmental health risk assessment (EHRA) ................................................................................. 7 1.8 Risk assessment frameworks ...................................................................................................................................... 9 1.9 Tiered approaches to EHRA ...................................................................................................................................... 12 1.10 Deterministic versus probabilistic estimates in EHRA ................................................................................................ 13 1.11 Environmental health risk assessment and health impact assessment ....................................................................... 14 1.12 Environmental health risk assessment and the ‘precautionary principle’ .................................................................... 14 Chapter 2: Problem formulation and scope .................................................................................................................................. 16 2.1 Identifying and describing issues within existing environmental conditions ................................................................. 16 2.2 Identifying and describing susceptible populations .................................................................................................... 17 2.3 Identification of potential exposure pathways............................................................................................................. 22 2.4 Potential interactions between agents ....................................................................................................................... 22 2.5 Identifying potential management options that may mitigate exposure ....................................................................... 23 2.6 What risk and other technical assessments are necessary to evaluate risk and discriminate between potential risk management options? .......................................................................................................................... 23 Chapter 3: Hazard identification and dose–response assessment .................................................................................................. 24 3.1 Introduction ............................................................................................................................................................. 24 3.2 Hazard identification................................................................................................................................................. 24 3.3 Dose–response assessment ...................................................................................................................................... 26 3.4 The prime role of animal studies in risk assessment .................................................................................................. 26 3.5 Dose scaling ............................................................................................................................................................. 26 3.6 Dose–response curve shape, construct and analysis ................................................................................................. 28 3.7 Hormesis ................................................................................................................................................................. 32 3.8 Dose–response modelling ......................................................................................................................................... 32 3.9 Benchmark dose approach....................................................................................................................................... 33 3.10 Threshold versus non-threshold responses in risk assessment .................................................................................. 36 3.11 Threshold versus non-threshold approaches – implications for risk assessment ......................................................... 39 3.12 Science policy and the selection of threshold and non-threshold models ................................................................... 40 ENVIRONMENTAL HEALTH RISK ASSESSMENT i Chapter 4: Exposure assessment ................................................................................................................................................. 42 Chapter 7: Reviewing and appraising an environmental health risk assessment report ................................................................... 95 4.1 Introduction ............................................................................................................................................................. 42 7.1 Problem formulation and scope ................................................................................................................................ 95 4.2 Terminology used in exposure assessment ................................................................................................................ 42 7.2 Hazard identification................................................................................................................................................. 95 4.3 Planning an exposure assessment ............................................................................................................................ 45 7.3 Dose–response checklist .......................................................................................................................................... 96 4.4 Development of a conceptual site model ................................................................................................................... 47 7.4 Selection of guideline values ..................................................................................................................................... 97 4.5 Approaches to quantifying exposures ........................................................................................................................ 50 7.5 Data presentation ..................................................................................................................................................... 97 4.6 Exposure assessment calculations ............................................................................................................................ 52 7.6 Exposure assessment ............................................................................................................................................... 98 4.7 Data analysis and evaluation ..................................................................................................................................... 53 7.7 Risk characterisation .............................................................................................................................................. 100 4.8 Individual exposure, dose and risk estimates............................................................................................................. 54 7.8 Confirmation of utility .............................................................................................................................................. 100 4.9 Issues in exposure assessments