SERA TR-052-26-03a Trifluralin Human Health and Ecological Risk Assessment FINAL REPORT Submitted to: Paul Mistretta, COR USDA/Forest Service, Southern Region 1720 Peachtree RD, NW Atlanta, Georgia 30309 USDA Forest Service Contract: AG-3187-C-06-0010 USDA Forest Order Number: AG-43ZP-D-10-0010 SERA Internal Task No. 52-26 Submitted by: Patrick R. Durkin Syracuse Environmental Research Associates, Inc. 8125 Solomon Seal Manlius, New York 13104 E-Mail: [email protected] Home Page: www.sera-inc.com September 20, 2011 Table of Contents LIST OF FIGURES ...................................................................................................................... vii LIST OF TABLES ........................................................................................................................ vii LIST OF APPENDICES .............................................................................................................. viii LIST OF ATTACHEMENTS ...................................................................................................... viii ACRONYMS, ABBREVIATIONS, AND SYMBOLS ................................................................ ix COMMON UNIT CONVERSIONS AND ABBREVIATIONS .................................................. xii CONVERSION OF SCIENTIFIC NOTATION ......................................................................... xiii EXECUTIVE SUMMARY ......................................................................................................... xiv 1. INTRODUCTION ...................................................................................................................... 1 2. PROGRAMS DESCRIPTION ................................................................................................... 3 2.1. Overview .............................................................................................................................. 3 2.2. Chemical Description and Commercial Formulations ......................................................... 3 2.3. Application Methods ............................................................................................................ 5 2.4. Mixing and Application Rates ............................................................................................. 6 2.5. Use Statistics ........................................................................................................................ 6 3. HUMAN HEALTH .................................................................................................................... 8 3.1. HAZARD IDENTIFICATION .......................................................................................... 8 3.1.1. Overview ....................................................................................................................... 8 3.1.2. Mechanism of Action .................................................................................................... 8 3.1.3. Pharmacokinetics and Metabolism ............................................................................... 9 3.1.3.1. General Considerations .......................................................................................... 9 3.1.3.2. Dermal Absorption............................................................................................... 11 3.1.3.2.1. First-Order Dermal Absorption..................................................................... 11 3.1.3.2.2. Zero-Order Dermal Absorption .................................................................... 13 3.1.3.3. Excretion .............................................................................................................. 14 3.1.4. Acute Oral Toxicity .................................................................................................... 15 3.1.5. Subchronic or Chronic Systemic Toxic Effects .......................................................... 17 3.1.6. Effects on Nervous System ......................................................................................... 19 3.1.7. Effects on Immune System ......................................................................................... 20 3.1.8. Effects on Endocrine System ...................................................................................... 21 3.1.9. Reproductive and Developmental Effects .................................................................. 22 3.1.9.1. Developmental Studies ........................................................................................ 22 3.1.9.2. Reproduction Studies ........................................................................................... 23 3.1.10. Carcinogenicity and Mutagenicity ............................................................................ 23 3.1.11. Irritation and Sensitization (Effects on the Skin and Eyes) ...................................... 24 3.1.12. Systemic Toxic Effects from Dermal Exposure ....................................................... 24 3.1.13. Inhalation Exposure .................................................................................................. 25 3.1.14. Adjuvants and Other Ingredients .............................................................................. 25 ii 3.1.15. Impurities and Metabolites ....................................................................................... 27 3.1.15.1. Metabolites ......................................................................................................... 27 3.1.15.2. Impurities ........................................................................................................... 28 3.1.16. Toxicological Interactions ........................................................................................ 29 3.2. EXPOSURE ASSESSMENT .......................................................................................... 30 3.2.1. Overview ..................................................................................................................... 30 3.2.2. Workers ....................................................................................................................... 31 3.2.2.1. General Exposures ............................................................................................... 31 3.2.2.2. Accidental Exposures........................................................................................... 32 3.2.3. General Public ........................................................................................................... 34 3.2.3.1. General Considerations ........................................................................................ 34 3.2.3.1.1. Likelihood and Magnitude of Exposure ....................................................... 34 3.2.3.1.2. Summary of Assessments ............................................................................. 34 3.2.3.2. Direct Spray ......................................................................................................... 35 3.2.3.3. Dermal Exposure from Contaminated Vegetation ............................................... 35 3.2.3.4. Contaminated Water ............................................................................................ 35 3.2.3.4.1. Accidental Spill ............................................................................................. 35 3.2.3.4.2. Accidental Direct Spray/drift for a Pond or Stream ...................................... 36 3.2.3.4.3. Gleams-Driver Modeling .............................................................................. 36 3.2.3.4.3.1. Inputs to Gleams-Driver ........................................................................ 36 3.2.3.4.3.2. Results from Gleams-Driver .................................................................. 38 3.2.3.4.4. Other Modeling Efforts ................................................................................. 39 3.2.3.4.5. Monitoring Data ............................................................................................ 40 3.2.3.4.5.1. Monitoring Studies Involving Defined Applications ............................. 40 3.2.3.4.5.1. Other Monitoring Data ........................................................................... 41 3.2.3.4.6. Concentrations in Water Used for Risk Assessment .................................... 42 3.2.3.5. Oral Exposure from Contaminated Fish .............................................................. 43 3.2.3.5.1. Bioconcentration ........................................................................................... 44 3.2.3.5.2. Consumption of Wild-Caught Fish ............................................................... 46 3.2.3.5.3. Accidental Exposure Scenarios ..................................................................... 46 3.2.3.6. Dermal Exposure from Swimming in Contaminated Water ................................ 47 3.2.3.6. Oral Exposure from Contaminated Vegetation.................................................... 48 3.3. DOSE-RESPONSE ASSESSMENT ................................................................................. 51 3.3.1. Overview ..................................................................................................................... 51 3.3.2. Acute RfD ................................................................................................................... 51 iii 3.3.3. Chronic RfD ................................................................................................................ 52 3.3.4.