SERA TR 05-43-20-03d Hexazinone - Human Health and Ecological Risk Assessment – Final Report Prepared for: USDA, Forest Service Forest Health Protection GSA Contract No. GS-10F-0082F USDA Forest Service BPA: WO-01-3187-0150 USDA Purchase Order No.: 43-1387-3-0717 Task No. 20 Submitted to: Hank Appleton, COTR Forest Health Protection Staff USDA Forest Service Rosslyn Plaza Building C, Room 7129C 1601 North Kent Street Arlington, VA 22209 Prepared by Patrick Durkin, Cynthia King, and Julie Klotzbach Submitted by: Syracuse Environmental Research Associates, Inc. 5100 Highbridge St., 42C Fayetteville, New York 13066-0950 Telephone: (315) 637-9560 Fax: (315) 637-0445 E-Mail: [email protected] Home Page: www.sera-inc.com October 25, 2005 TABLE OF CONTENTS TABLE OF CONTENTS....................................................... ii LIST OF APPENDICES ........................................................v LIST OF TABLES ............................................................ vi LIST OF FIGURES .......................................................... vii LIST OF ATTACHMENTS ................................................... vii ACRONYMS, ABBREVIATIONS, AND SYMBOLS . viii COMMON UNIT CONVERSIONS AND ABBREVIATIONS . x CONVERSION OF SCIENTIFIC NOTATION ..................................... xi EXECUTIVE SUMMARY .................................................... xii 1. INTRODUCTION......................................................... 1-1 2. PROGRAM DESCRIPTION ................................................ 2-1 2.1. OVERVIEW ..................................................... 2-1 2.2. CHEMICAL DESCRIPTION AND COMMERCIAL FORMULATIONS . 2-1 2.3. APPLICATION METHODS ......................................... 2-2 2.4. MIXING AND APPLICATION RATES................................ 2-3 2.5. USE STATISTICS................................................. 2-4 3. HUMAN HEALTH RISK ASSESSMENT ..................................... 3-1 3.1. HAZARD IDENTIFICATION ....................................... 3-1 3.1.1. Overview. ................................................ 3-1 3.1.2. Mechanism of Action........................................ 3-2 3.1.3. Kinetics and Metabolism. .................................... 3-3 3.1.4. Acute Oral Toxicity. ........................................ 3-6 3.1.5. Subchronic or Chronic Systemic Toxic Effects. 3-6 3.1.6. Effects on Nervous System. .................................. 3-8 3.1.7. Effects on Immune System. .................................. 3-8 3.1.8. Effects on Endocrine System. ................................. 3-9 3.1.9. Reproductive and Developmental Effects. 3-10 3.1.10. Carcinogenicity and Mutagenicity. 3-11 3.1.11. Irritation and Sensitization (Effects on the Skin and Eyes). 3-12 3.1.12. Systemic Toxic Effects from Dermal Exposure. 3-14 ii TABLE OF CONTENTS (continued) 3.1.13. Inhalation Exposure. ...................................... 3-15 3.1.14. Inerts and Adjuvants. ..................................... 3-16 3.1.15. Impurities and Metabolites.................................. 3-17 3.1.16. Toxicologic Interactions. .................................. 3-18 3.2. EXPOSURE ASSESSMENT ....................................... 3-19 3.2.1. Overview. ............................................... 3-19 3.2.2. Workers. ................................................ 3-20 3.2.2.1. General Exposures ................................. 3-20 3.2.2.2. Accidental Exposures............................... 3-22 3.2.3. General Public. ........................................... 3-24 3.2.3.1. General Considerations . 3-24 3.2.3.2. Direct Spray ...................................... 3-25 3.2.3.3. Dermal Exposure from Contaminated Vegetation . 3-25 3.2.3.4. Contaminated Water ............................... 3-26 3.2.3.4.1. Accidental Spill............................ 3-26 3.2.3.4.2. Accidental Direct Spray/drift for a Pond or Stream ............................. 3-27 3.2.3.4.3. Gleams Modeling .......................... 3-27 3.2.3.4.4. Other Modeling Efforts . 3-30 3.2.3.4.5. Monitoring Data ........................... 3-31 3.2.3.4.6. Concentrations in Water Used for Risk Assessment............................ 3-32 3.2.3.5. Oral Exposure from Contaminated Fish . 3-34 3.2.3.6. Oral Exposure from Contaminated Vegetation . 3-34 3.3. DOSE-RESPONSE ASSESSMENT .................................. 3-36 3.3.1. Overview................................................ 3-36 3.3.2. Chronic RfD ............................................. 3-36 3.3.2. Acute RfD ............................................... 3-37 3.4. RISK CHARACTERIZATION ...................................... 3-39 3.4.1. Overview................................................ 3-39 3.4.2. Workers................................................. 3-39 3.4.3. General Public. ........................................... 3-40 3.4.4. Sensitive Subgroups........................................ 3-42 3.4.5. Connected Actions......................................... 3-42 3.4.6. Cumulative Effects......................................... 3-43 iii TABLE OF CONTENTS (continued) 4. ECOLOGICAL RISK ASSESSMENT......................................... 4-1 4.1. HAZARD IDENTIFICATION ....................................... 4-1 4.1.1. Overview. ................................................ 4-1 4.1.2. Toxicity to Terrestrial Organisms. 4-1 4.1.2.1. Mammals ......................................... 4-1 4.1.2.2. Birds............................................. 4-2 4.1.2.3. Terrestrial Invertebrates . 4-4 4.1.2.4. Terrestrial Plants (Macrophytes) . 4-5 4.1.2.5. Terrestrial Microorganisms . 4-6 4.1.3. Aquatic Organisms.......................................... 4-7 4.1.3.1. Fish.............................................. 4-7 4.1.3.2. Amphibians ....................................... 4-8 4.1.3.3. Aquatic Invertebrates ................................ 4-8 4.1.3.4. Aquatic Plants .................................... 4-10 4.2. EXPOSURE ASSESSMENT ....................................... 4-12 4.2.1. Overview. ............................................... 4-12 4.2.2. Terrestrial Animals. ....................................... 4-12 4.2.2.1. Direct Spray ...................................... 4-14 4.2.2.2. Indirect Contact ................................... 4-14 4.2.2.3. Ingestion of Contaminated Vegetation or Prey . 4-14 4.2.2.4. Ingestion of Contaminated Water . 4-15 4.2.3. Terrestrial Plants. ......................................... 4-16 4.2.3.1. Direct Spray ...................................... 4-16 4.2.3.2. Off-Site Drift ..................................... 4-16 4.2.3.3. Runoff .......................................... 4-16 4.2.3.4. Contaminated Irrigation Water . 4-17 4.2.3.5. Wind Erosion ..................................... 4-18 4.2.4. Soil Organisms............................................ 4-18 4.2.5. Aquatic Organisms......................................... 4-19 4.3. DOSE-RESPONSE ASSESSMENT .................................. 4-20 4.3.1. Overview. ............................................... 4-20 4.3.2. Toxicity to Terrestrial Organisms. 4-21 4.3.2.1. Mammals ........................................ 4-21 4.3.2.2. Birds............................................ 4-21 4.3.2.3. Terrestrial Invertebrates . 4-22 4.3.2.4. Terrestrial Plants (Macrophytes) . 4-23 4.3.2.5. Terrestrial Microorganisms . 4-23 4.3.3. Aquatic Organisms......................................... 4-23 4.3.3.1. Fish............................................. 4-22 4.3.3.2. Amphibians ...................................... 4-24 4.3.3.3. Aquatic Invertebrates ............................... 4-24 4.3.3.4. Aquatic Plants .................................... 4-25 iv TABLE OF CONTENTS (continued) 4.4. RISK CHARACTERIZATION ...................................... 4-26 4.4.1. Overview. ............................................... 4-26 4.4.2. Terrestrial Organisms....................................... 4-27 4.4.2.1. Mammals ........................................ 4-27 4.4.2.2. Birds............................................ 4-28 4.4.2.3. Terrestrial Invertebrates . 4-29 4.4.2.4. Terrestrial Plants .................................. 4-29 4.4.2.5. Soil Microorganisms ............................... 4-31 4.4.3. Aquatic Organisms......................................... 4-31 4.4.3.1. Fish............................................. 4-31 4.4.3.2. Amphibians ...................................... 4-31 4.4.3.3. Aquatic Invertebrates ............................... 4-32 4.4.3.4. Aquatic Plants .................................... 4-32 5. REFERENCES ........................................................... 5-1 LIST OF APPENDICES Appendix 1: Acute Toxicity to Mammals Appendix 2: Repeated Dose Studies in Mammals Appendix 3: Toxicity to Birds Appendix 4: Toxicity to Terrestrial Invertebrates and Soil Microorganisms Appendix 5: Toxicity to Terrestrial Plants Appendix 6: Field or field simulation studies on effects of hexazinone Appendix 7: Field or field simulation studies on environmental fate of hexazinone Appendix 8: Physical Chemical Properties And Laboratory Studies on Environmental Fate Appendix 9: Toxicity to Fish and Amphibians Appendix 10: Toxicity to Aquatic Invertebrates Appendix 11: Toxicity to Aquatic Plants Appendix 12: GLEAMS Modeling for Granular Applications Appendix 13: GLEAMS Modeling with minimal degradation to simulate exposures to metabolites v LIST OF TABLES Table 2-1: Identification and physical/chemical properties of hexazinone . Tables-1 Table 2-2: Hexazinone Formulations