United States Prevention, Pesticides EPA 738-R-05-008 Environmental Protection and Toxic Substances September 2005 Agency (7508C) Reregistration Eligibility Decision for Endothall i Reregistration Eligibilit y Decision (RED) Document for Endothall List B Case Number 2245 Approved by: Date: Debra Edwards, Ph. D. Director Special Review and Reregistration Division ii Table of Contents Endothall Reregistration Eligibility Decision Team.............................................................i Glossary of Terms and Abbreviations ................................................................................ ii Abstract ...............................................................................................................................iv I. Introduction...................................................................................................................... 1 II. Chemical Overview........................................................................................................ 2 A. Endothall and Salts Nomenc lature ............................................................................. 3 B. Use Sites..................................................................................................................... 3 C. Formulations ............................................................................................................... 3 D. Methods of application............................................................................................... 3 E. Use rates ..................................................................................................................... 4 F. Annual usage ............................................................................................................... 4 G. Tolerances in Use Profile ........................................................................................... 4 H. Technical Registrant ................................................................................................... 5 III. Summary of Risk Assessment ...................................................................................... 5 A. Human Health Risk Assessment ................................................................................ 5 1. Hazard Profile ......................................................................................................... 5 2. Dietary Risk (Food) ................................................................................................ 7 a. Acute Dietary Risk (Food ................................................................................... 8 b. Chronic Dietary Risk (Food) .............................................................................. 8 3. Cancer Dietary Risk (Food) .................................................................................. 10 4. Drinking Water Dietary Risk ................................................................................ 10 a. Aquatic Uses ..................................................................................................... 10 b. Terrestrial Uses ................................................................................................. 12 5. Chronic Risk from Food Plus Drinking Water ..................................................... 12 6. Residential Risk .................................................................................................... 13 7. Aggregate Risk...................................................................................................... 14 8. Occupational Risk................................................................................................. 14 a. Occupational Handler Summary....................................................................... 15 i. Terrestrial Applications ................................................................................. 15 ii. Aquatic Applications .................................................................................... 15 iii. Cooling Tower (Biocide) Applications ....................................................... 16 b. Post-application Occupational Risk .................................................................. 16 9. Human Incident Summary.................................................................................... 17 B. Ecological Risk......................................................................................................... 17 1. Environmental Fate and Transport........................................................................ 17 2. Terrestrial Organism Risk..................................................................................... 18 a. Risks from Use of Endothall N, N-dimethylalkylamine Salt............................ 18 3. Aquatic Organism Risk......................................................................................... 19 a. Risks from Use of Endothall N, N-dimethylalkylamine Salt............................ 19 b. Risks from Use of Endothall Dipotassium Salt ................................................ 20 c. Risks from Endothall Acid ................................................................................ 20 4. Risk to Endangered Species.................................................................................. 21 a. Risks from Use of Endothall N, N-dimethylalkylamine Salt............................ 21 b. Risks from Use of Endothall Dipotassium Salt ................................................ 22 iii IV. Risk Management, Reregistration, and Tolerance Reassessment Decision............... 22 A. Determination or Reregistration Eligibility............................................................. 22 B. Public Comments and Responses............................................................................. 23 C. Regulatory Position.................................................................................................. 23 1. Food Quality Protection Act Findings .................................................................. 23 a. "Risk Cup" Determination ................................................................................ 23 b. Determination of Safety to U.S. Population (Including Infants and Children) 24 c. Endocrine Disruptor Effects.............................................................................. 24 d. Cumulative Risks .............................................................................................. 25 2. Tolerance Summary.............................................................................................. 25 a. Tolerances Currently Listed and Tolerance Reassessme nt ............................... 27 D. Regulatory Rationale................................................................................................ 28 a. Dietary Risk Mitigation (food and drinking water) .......................................... 28 1. Human Health Risk Management......................................................................... 29 a. Occupational Risk Mitigation ........................................................................... 29 b. Residential Risk Mitigation .............................................................................. 29 2. Environmental Risk Management......................................................................... 30 a. Dipotassium Salt ............................................................................................... 30 b. N, N-dimethylalkylamine Salt .......................................................................... 30 3. Significance of Endothall Use............................................................................... 30 4. Other Labeling Requirements ............................................................................... 31 5. Threatened and Endangered Species Considerations............................................ 32 a. The Endangered Species Program..................................................................... 32 b. General Risk Mitigation.................................................................................... 32 V. What Registrants Need to Do....................................................................................... 33 A. Manufacturing Use Products.................................................................................... 34 1. Additional Generic Data Requirements ................................................................ 34 2. Labeling for Technical and Manufacturing Use Products .................................... 35 B. End-Use products ..................................................................................................... 36 1. Additional Product-Specific Data Requirements .................................................. 36 2. Labeling for End-Use Products............................................................................. 36 a. Label Changes Summary Table ........................................................................ 36 VI. Appendices.................................................................................................................. 47 A. Table of Use Patterns for Endothall ............................................................................. 48 B.Generic Data Requirements and Studies Used to Make the Reregistration Decision63 C. Technical Support Documents ................................................................................. 70 D. Bibliography............................................................................................................