EPA Document# 746-R1-4001 August 2014 Office of Chemical Safety and Pollution Prevention TSCA Work Plan Chemical Risk Assessment HHCB 1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-γγγ-2- benzopyran CASRN: 1222-05-5 CH3 H3C CH3 CH3 O CH3 H3C August 2014 TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................. 2 LIST OF TABLES ...................................................................................................................... 5 LIST OF APPENDIX TABLES ..................................................................................................... 5 LIST OF FIGURES .................................................................................................................... 7 LIST OF APPENDIX FIGURES .................................................................................................... 7 AUTHORS/CONTRIBUTORS/ACKNOWLEDGEMENTS/REVIEWERS............................................ 8 GLOSSARY OF TERMS AND ABBREVIATIONS ......................................................................... 10 EXECUTIVE SUMMARY ......................................................................................................... 12 1 BACKGROUND AND SCOPE ........................................................................................... 14 1.1 INTRODUCTION .......................................................................................................................................... 14 1.2 PROBLEM FORMULATION .......................................................................................................................... 16 1.3 CONCEPTUAL MODEL FOR ENVIRONMENTAL ASSESSMENT ...................................................................... 17 1.4 ANALYSIS PLAN FOR ENVIRONMENTAL ASSESSMENT ................................................................................ 19 2 SOURCES AND ENVIRONMENTAL FATE ......................................................................... 20 2.1 INTRODUCTION .......................................................................................................................................... 20 2.1.1 Physical and Chemical Properties ...................................................................................................... 20 2.2 PRODUCTION AND USES ............................................................................................................................. 21 2.2.1 Production .......................................................................................................................................... 22 2.2.2 Uses .................................................................................................................................................... 24 2.2.3 Conclusions of Production and Use .................................................................................................... 26 2.3 ENVIRONMENTAL FATE .............................................................................................................................. 26 2.3.1 Environmental Persistence ................................................................................................................. 26 2.3.1.1 Fate in Wastewater Treatment ........................................................................................................................ 26 2.3.1.2 Fate in Water .................................................................................................................................................... 27 2.3.1.3 Fate in Soil and Sediment ................................................................................................................................. 28 2.3.1.4 Fate in Air ......................................................................................................................................................... 30 2.3.2 Bioaccumulation and Bioconcentration ............................................................................................. 30 2.3.3 Conclusions of Environmental Fate .................................................................................................... 33 3 ENVIRONMENTAL ASSESSMENT .................................................................................... 34 3.1 INTRODUCTION .......................................................................................................................................... 34 3.2 ENVIRONMENTAL EXPOSURE ASSESSMENT ............................................................................................... 34 3.2.1 Estimated Environmental Releases .................................................................................................... 34 3.2.2 Measured Levels in the Environment ................................................................................................. 34 3.2.2.1 Wastewater ...................................................................................................................................................... 37 3.2.2.2 Surface Water ................................................................................................................................................... 37 3.2.2.3 Sediment .......................................................................................................................................................... 38 3.2.2.4 Biosolids and Soil .............................................................................................................................................. 38 3.2.2.5 Biota ................................................................................................................................................................. 39 3.2.2.6 USGS Data Analysis ........................................................................................................................................... 39 3.2.3 Conclusions of Environmental Exposure ............................................................................................ 40 3.3 ECOLOGICAL HAZARD ASSESSMENT ........................................................................................................... 40 Page 2 of 136 3.3.1 Acute Toxicity to Aquatic Organisms ................................................................................................. 41 3.3.2 Chronic Toxicity to Aquatic Organisms .............................................................................................. 42 3.3.3 Toxicity to Sediment-Dwelling Organisms ......................................................................................... 45 3.3.4 Toxicity to Terrestrial Organisms ....................................................................................................... 46 3.3.5 Conclusions of Environmental Hazard Assessment ............................................................................ 49 3.4 ENVIRONMENTAL RISK CHARACTERIZATION ............................................................................................. 49 3.4.1 Calculation of Risk Quotient (RQ) Values ........................................................................................... 49 3.4.2 Key Sources of Uncertainty and Data Limitations .............................................................................. 52 3.4.2.1 Representativeness of Exposure Concentrations ............................................................................................. 52 3.4.2.2 Variability in Environmental Concentrations .................................................................................................... 52 3.4.2.3 Anaerobic Degradation..................................................................................................................................... 53 3.4.2.4 Volatilization ..................................................................................................................................................... 53 3.4.2.5 Isomers and Metabolites .................................................................................................................................. 53 3.4.2.6 Deriving Concentrations of Concern from Single Species Tests ....................................................................... 53 3.4.2.7 Assessment of Risk to Terrestrial Invertebrates or Plants ................................................................................ 54 3.4.3 Conclusions of Risk Characterization ................................................................................................. 54 3.5 CONCLUSIONS OF ENVIRONMENTAL ASSESSMENT ................................................................................... 54 REFERENCES ........................................................................................................................ 55 APPENDICES ........................................................................................................................ 77 Appendix A HUMAN HEALTH TOXICITY STUDIES, BIOMONITORING DATA, AND RISK ASSESSMENTS ................................................................................................. 78 A-1 HUMAN HAZARD CHARACTERIZATION ............................................................................................................... 78 A-1-1 Toxicokinetics (Absorption, Distribution, Metabolism, Excretion) ..................................................... 78 A-1-2 Acute Toxicity 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