Peer Review Draft Guidelines for Human Exposure Assessment Risk Assessment Forum U.S. Environmental Protection Agency Peer Review Draft January 7, 2016 Peer Review Draft DISCLAIMER This document is being circulated for public review and comment. It should not be construed as representing EPA policies or practices. Do not cite or quote. LIST OF AUTHORS AND CONTRIBUTORS Nicolle Tulve, Chair Marian Olsen, Co-Chair Michael Broder, Science Coordinator Michael Firestone Eloise Mulford Linda Sheldon Cynthia Stahl Valerie Zartarian Page | iii Peer Review Draft TABLE OF CONTENTS DISCLAIMER .......................................................................................................................................... iii LIST OF AUTHORS AND CONTRIBUTORS....................................................................................... iii LIST OF TABLES ................................................................................................................................. viii LIST OF FIGURES ................................................................................................................................ viii LIST OF BOXES ..................................................................................................................................... ix ABBREVIATIONS AND ACRONYMS .................................................................................................. x PREFACE ................................................................................................................................................ xii EXECUTIVE SUMMARY .................................................................................................................... xiii CHAPTER 1. INTRODUCTION .............................................................................................................. 1 1.1. Overview ................................................................................................................................... 1 1.2. Purpose and Scope of the Guidelines ........................................................................................ 1 1.3. Organization of Guidelines for Human Exposure Assessment ................................................. 3 CHAPTER 2. PRINCIPLES OF EXPOSURE SCIENCE/EXPOSURE ASSESSMENT ........................ 4 2.1. Exposure Science ...................................................................................................................... 4 2.2. Definitions ................................................................................................................................ 8 2.2.1. Exposure Definitions ....................................................................................................... 8 2.2.2. Dose Definitions .............................................................................................................. 8 2.3. Concepts in Exposure Assessment .......................................................................................... 12 2.3.1. The Risk Assessment Process ....................................................................................... 12 2.3.2. Overview of Exposure Assessment ............................................................................... 13 2.3.3. Approaches for Exposure Assessment .......................................................................... 13 2.3.4. Uncertainty and Variability in Exposure Assessments .................................................. 16 2.4. Calculating Exposure Estimates.............................................................................................. 17 2.4.1. Inhalation Exposure ....................................................................................................... 17 2.4.2. Ingestion (Dietary and Nondietary) Exposure ............................................................... 18 2.4.3. Dermal Exposure ........................................................................................................... 18 2.5. Development of Exposure Science and Exposure Assessments Related to EPA Risk Assessments ........................................................................................................ 19 CHAPTER 3. PLANNING AND SCOPING AND PROBLEM FORMULATION .............................. 24 3.1. Planning and Scoping ............................................................................................................. 26 3.1.1. Exposure Assessment Goals and Scope ........................................................................ 27 3.1.2. Overarching Considerations .......................................................................................... 29 3.1.3. Public, Stakeholder and Community Involvement ........................................................ 30 3.1.4. Peer Review ................................................................................................................... 31 3.2. Problem Formulation .............................................................................................................. 33 3.2.1. Individuals/Lifestages/Groups/Populations ................................................................... 33 3.2.2. Conceptual Model ......................................................................................................... 34 3.3. Analysis Plan .......................................................................................................................... 36 3.3.1. Data Sources, Gaps, Limitations and Quality Objectives ............................................. 36 3.3.2. Environmental Scenarios ............................................................................................... 37 3.4. Communication Strategy ........................................................................................................ 38 CHAPTER 4. CONSIDERATION OF LIFESTAGES, VULNERABLE GROUPS AND POPULATIONS OF CONCERN IN EXPOSURE ASSESSMENTS .......................................... 39 Page | iv Peer Review Draft 4.1. History of EPA Exposure Assessments for Lifestages, Vulnerable Groups and Populations of Concern ................................................................................................. 40 4.2. Vulnerability and Susceptibility in Exposure Assessment ..................................................... 40 4.3. Examples of Lifestages, Vulnerable Groups and Populations of Concern in Exposure Assessment ........................................................................................................... 43 4.3.1. Lifestages....................................................................................................................... 43 4.3.2. Childhood ...................................................................................................................... 44 4.3.3. Other Lifestages ............................................................................................................ 47 4.3.4. Integrating Age-Specific Values in Exposure Assessment ........................................... 47 4.3.5. Tribal Populations ......................................................................................................... 48 4.3.6. Other Racial and Ethnic Populations ............................................................................. 52 4.3.7. Socioeconomically Disadvantaged Populations ............................................................ 53 4.4. Identifying Lifestages, Vulnerable Groups and Populations of Concern for Exposure Assessment ........................................................................................................... 58 4.4.1. Traditional Methods ...................................................................................................... 58 4.4.2. Case Studies .................................................................................................................. 58 4.4.3. Neighborhood Methods ................................................................................................. 58 4.4.4. Population-Based Methods ............................................................................................ 59 4.4.5. Social Process Methods ................................................................................................. 59 4.4.6. National Level versus Local/Community-Specific Assessments .................................. 59 CHAPTER 5. DATA FOR EXPOSURE ASSESSMENT ...................................................................... 61 5.1. Identifying Data Gaps and Data Needs ................................................................................... 61 5.2. Data Quality ............................................................................................................................ 64 5.2.1. Data Usability and Determining Whether Data Meet Assessment Factors ........................................................................................................................ 64 5.2.2. Assessment – Using Data to Evaluate Exposures ......................................................... 70 5.3. Types of Data Used in an Exposure Assessment .................................................................... 72 5.3.1. Environmental Data ....................................................................................................... 72 5.3.2. Biomonitoring Data ....................................................................................................... 72 5.3.3. Exposure Factors ..........................................................................................................