SERA TR-052-02-02c Malathion 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-06-0012 SERA Internal Task No. 52-02 Submitted by: Patrick R. Durkin Syracuse Environmental Research Associates, Inc. 5100 Highbridge St., 42C Fayetteville, New York 13066-0950 Fax: (315) 637-0445 E-Mail: [email protected] Home Page: www.sera-inc.com May 12, 2008 Table of Contents Table of Contents............................................................................................................................ ii List of Figures................................................................................................................................. v List of Tables ................................................................................................................................. vi List of Appendices ......................................................................................................................... vi List of Attachments........................................................................................................................ vi ACRONYMS, ABBREVIATIONS, AND SYMBOLS ............................................................... vii COMMON UNIT CONVERSIONS AND ABBREVIATIONS.................................................... x CONVERSION OF SCIENTIFIC NOTATION ........................................................................... xi EXECUTIVE SUMMARY .......................................................................................................... xii 1. INTRODUCTION ...................................................................................................................... 1 2. PROGRAM DESCRIPTION..................................................................................................... 4 2.1. OVERVIEW ....................................................................................................................... 4 2.2. CHEMICAL DESCRIPTION AND COMMERCIAL FORMULATIONS....................... 5 2.3. APPLICATION METHODS.............................................................................................. 7 2.4. MIXING AND APPLICATION RATES ........................................................................... 7 2.4.1. Mosquito Control.......................................................................................................... 7 2.4.2. Pest Control in Seed Orchards ...................................................................................... 8 2.4.3. Other Pest Control Applications ................................................................................... 9 2.5. USE STATISTICS.............................................................................................................. 9 3. HUMAN HEALTH RISK ASSESSMENT............................................................................. 11 3.1. HAZARD IDENTIFICATION......................................................................................... 11 3.1.1. Overview.................................................................................................................... 11 3.1.2. Mechanism of Action................................................................................................. 13 3.1.3. Pharmacokinetics ....................................................................................................... 14 3.1.3.1. Overview of Information ..................................................................................... 14 3.1.3.2. Kinetic Values Used in Risk Assessment ............................................................ 17 3.1.4. Acute Oral Toxicity ................................................................................................... 19 3.1.5. Subchronic or Chronic Systemic Toxic Effects......................................................... 20 3.1.6. Effects on Nervous System........................................................................................ 22 3.1.7. Effects on Immune System ........................................................................................ 25 3.1.7.1. General Considerations....................................................................................... 25 3.1.7.2. Immune Enhancement ......................................................................................... 26 3.1.7.3. Immune Suppression............................................................................................ 27 3.1.7.4. U.S. EPA and ATSDR Evaluations of Immunotoxicity...................................... 28 3.1.8. Effects on Endocrine System..................................................................................... 30 3.1.9. Reproductive and Teratogenic Effects....................................................................... 31 3.1.9.1. Developmental (Teratology) Studies ................................................................... 31 3.1.9.2. Reproduction Studies........................................................................................... 32 3.1.9.3. Developmental Neurotoxicity.............................................................................. 33 3.1.9.4. Target Organ Toxicity.......................................................................................... 33 3.1.9.5. Human Data ......................................................................................................... 34 ii 3.1.10. Carcinogenicity and Mutagenicity........................................................................... 35 3.1.10.1. Mutagenicity ...................................................................................................... 35 3.1.10.2. Carcinogenicity.................................................................................................. 37 3.1.11. Irritation and Sensitization (Effects on the Skin and Eyes) ..................................... 39 3.1.12. Systemic Toxic Effects from Dermal Exposure ...................................................... 40 3.1.13. Inhalation Exposure ................................................................................................. 40 3.1.14. Inerts and Adjuvants ................................................................................................ 40 3.1.15. Impurities and Metabolites .................................................................................. 41 3.1.15.1. Metabolites........................................................................................................ 41 3.1.15.2. Impurities ........................................................................................................... 42 3.1.16. Toxicological Interactions ....................................................................................... 44 3.2. EXPOSURE ASSESSMENT ........................................................................................... 47 3.2.1. Overview.................................................................................................................... 47 3.2.2. Workers...................................................................................................................... 48 3.2.2.1. General Exposures .............................................................................................. 49 3.2.2.2. Accidental Exposures.......................................................................................... 50 3.2.3. General Public............................................................................................................ 52 3.2.3.1.1. Malaoxon Exposures..................................................................................... 52 3.2.3.1.2. Likelihood and Magnitude of Exposure ....................................................... 56 3.2.3.1.3. Summary of Assessments ............................................................................. 57 3.2.3.2. Direct Spray ........................................................................................................ 57 3.2.3.3. Dermal Exposure from Contaminated Vegetation.............................................. 58 3.2.3.4. Contaminated Water ............................................................................................ 58 3.2.3.4.1. Accidental Spill............................................................................................ 59 3.2.3.4.2. Accidental Direct Spray/Drift for a Pond or Stream..................................... 59 3.2.3.4.3. GLEAMS Modeling..................................................................................... 60 3.2.3.4.4. Other Modeling Efforts................................................................................. 61 3.2.3.4.5. Monitoring Data............................................................................................ 62 3.2.3.4.6. Concentrations in Water Used for Risk Assessment .................................... 62 3.2.3.5. Oral Exposure from Contaminated Fish .............................................................. 64 3.2.3.6. Dermal Exposure from Swimming in Contaminated Water................................ 65 3.2.3.7. Oral Exposure from Contaminated Vegetation.................................................... 66 3.3. DOSE-RESPONSE ASSESSMENT ................................................................................ 67 3.3.1. Overview...................................................................................................................