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REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) xx-10-1999 Technical 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Final Methyl tert-Butyl Ether (MTBE), Its Movement and Fate in the Environment and Potential for Natural Attenuation, 5b. GRANT NUMBER Technical Summary Report 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Parsons Engineering Science, Inc. 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER Parsons Engineering Science, Inc. 1700 Broadway, Suite 900, Denver, CO 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) Air Force Center for AFCEE Environmental Excellence 3300 Sidney Brooks 11. SPONSOR/MONITOR’S REPORT Brooks City-Base, TX 78235 NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT This report summarizes the approach to be followed when evaluating the natural attenuation of MTBE and other fuel oxygenate and considers the consequences of the unique physical and chemical characteristics and their resultant behavior in the environment. 15. SUBJECT TERMS MTBE, natural attenuation, fuel hydrocarbons, oxygenates, biodegradation, groundwater remediation, geochemistry, contaminant destruction rates 16. SECURITY CLASSIFICATION OF: 17. LIMITATION 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON UNCLASSIFIED OF ABSTRACT OF PAGES Mr. Jerry Hansen a. REPORT b. ABSTRACT c. THIS PAGE SAR 221 19b. TELEPHONE NUMBER (include area U U U code) 210-536-4353 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 FINAL CH 3 HC CH Methy3 lterO t 3-ButylEther CH MTBE 3 CH O (MTBE) 3 H3C C O C H CH 3 CH 3 H3C C OH t-ButylFormate (TBF) CH Its3 Movement t-ButylAlcohol (TBA) and Fatein O HO H3C C CH 3 theEnvironmenAcetontane d H3C C CH 3 O PotentialfoH rNaturalAttenuation 2-Propanol H3C C CH 3 MethylAcetate October1999 AirForceCenterfor EnvironmentalExcellence 1700Broadway,Suite900•Denver,Colorado80290 FINAL Methyl tert-Butyl Ether (MTBE) – Its Movement and Fate in the Environment and Potential for Natural Attenuation Technical Summary Report October 1999 Prepared For Air Force Center for Environmental Excellence Technology Transfer Division Brooks Air Force Base San Antonio, Texas Prepared By Parsons Engineering Science, Inc. 1700 Broadway, Suite 900 Denver, Colorado 80290 TABLE OF CONTENTS Page ACRONYMS AND ABBREVIATIONS.........................................................................v SECTION 1 - INTRODUCTION.................................................................................1-1 SECTION 2 - PROPERTIES AND ENVIRONMENTAL FATE OF MTBE................2-1 2.1 History of Development and Use of Methyl Tert-Butyl Ether............................2-1 2.2 Sources of MTBE in the Environment...............................................................2-4 2.2.1MTBE in Air.........................................................................................2-4 2.2.2MTBE in Ambient Groundwater............................................................2-5 2.3 Regulatory Standards for MTBE.......................................................................2-7 2.4 Physical and Chemical Composition of Fuel Hydrocarbons and Oxygenates.......................................................................................................2-8 2.4.1Chemical Structure of Hydrocarbon Compounds...................................2-9 2.4.1.1 Composition of Petroleum-Based Fuels.................................2-9 2.4.1.2 MTBE, TBA, and TBF.......................................................2-10 2.5 Phase Partitioning of Chemicals in the Environment........................................2-12 2.6 Physical and Chemical Transport and Attenuation Mechanisms for MTBE......2-17 2.6.1Solubility and Dissolution....................................................................2-17 2.6.2Advective Transport............................................................................2-21 2.6.3Dispersion...........................................................................................2-22 2.6.4Solid/Liquid Partitioning and Retardation............................................2-23 2.6.5Volatilization.......................................................................................2-28 2.7 Biodegradation of MTBE................................................................................2-29 2.7.1Overview of Biodegradation Processes................................................2-29 2.7.2Degradation as a First-Order Process...................................................2-33 2.7.3Potential for Biodegradation of MTBE................................................2-34 2.7.4Microcosm Investigations of MTBE Degradation................................2-37 2.7.5Field-Scale Investigations of MTBE Degradation................................2-41 2.7.5.1 MTBE Degradation Experiment, CFB Borden.....................2-45 2.7.5.2 U.S. Geological Survey UST Field Site, Laurel Bay Exchange, Beaufort, South Carolina....................................2-47 2.7.5.3 South Platte River Two-Plume Site, Denver, Colorado........2-48 -i- 022/733939/18.doc TABLE OF CONTENTS (Continued) Page 2.7.5.4 UST Site, Sampson County, North Carolina........................2-42 2.7.5.5 Leaking Underground Storage Tank Site, East Patchogue, New York.........................................................2-49 2.7.5.6 U.S. Coast Guard Support Center, Elizabeth City, North Carolina....................................................................2-51 2.7.5.7 Fire Station Spill, Elizabeth City, North Carolina.................2-52 2.7.5.8 Service Station UST Site, Michigan.....................................2-52 2.7.6Summary.............................................................................................2-53 2.8 Results of multi-site MTBE Plume Studies......................................................2-53 SECTION 3 - METHODS FOR EVALUATING NATURAL ATTENUATION OF MTBE............................................................................................3-1 3.1 Review Existing Site Information......................................................................3-7 3.2 Develop Preliminary Conceptual Model and Assess Potential for Natural Attenuation.......................................................................................................3-8 3.3 Perform Site Characterization in Support of Natural Attenuation.......................3-9 3.4 Refine Conceptual Model, Complete Pre-Modeling Calculations, and Document Indicators of Natural Attenuation...................................................3-15 3.5 Simulate Natural Attenuation Using Solute Fate and Transport Models...........3-15 3.6 Prepare Long-Term Monitoring Plan...............................................................3-16 3.7 Regulatory Considerations..............................................................................3-17 SECTION 4 - CONCLUSIONS AND RECOMMENDATIONS..................................4-1 SECTION 5 - REFERENCES......................................................................................5-1 Appendix A: Annotated Bibliography of MTBE References Appendix B: Participation in Oxyfuels and RFG Programs, MTBE Content of Representative Gasolines, and State Regulations Dealing With MTBE Appendix C: Partitioning of MTBE Between Dissolved and Vapor Phases Appendix D: Chemical Analyses for Fuel Constituents in Environmental Samples Appendix E: Methods of Quantifying Biodegradation Rates Appendix F: Comments to Draft Report by Waste Policy Institute, with Parsons ES’ Responses -ii- 022/733939/18.doc TABLE OF CONTENTS (Continued) LIST OF TABLES No. Title Page 2.1 Properties of Common Gasoline Constituents and MTBE Degradation Products.........................................................................................................2-18 2.2 Calculation of Retardation Coefficients...........................................................2-26 2.3 Summary of MTBE Microcosm Studies..........................................................2-38 2.4 Summary of MTBE Field Investigations..........................................................2-39 3.1 Soil and Groundwater Analytical Protocol.......................................................3-10 LIST OF FIGURES No. Title Page 2.1 Chemical Structure of MTBE..........................................................................2-12 2.2 UST Leak and Dissolved Hydrocarbon Plume.................................................2-15