1、API PUBL*460L 74 O732290 0533702 189 Transport and Fate of Dissolved Methanol, Methyl-Tertiary-Butyl-Ether, and Monoaromatic Hydrocarbons in a Shallow Sand Aquifer HEALTH AND ENVIRONMENTAL SCIENCES API PUBLICATION NUMBER 4601 APRIL 1994 d- Strategies for Todays Environmental Partnership American Pet
2、roleum Institute 1220 L Street. Northwest 11 Washington, D.C. 20005 API PUBLd4bOL 94 0732290 0533703 015 W Transport and Fate of Dissolved Methanol, Methyl-Tertiary-Butyl-Ether, and Monoaromatic Hydrocarbons in a Shallow Sand Aquifer Health and Environmental Sciences Department API PUBLICATION NUMBE
3、R 4601 PREPARED UNDER CONTRACT BY: C.E. HUBBARD J.F. BARKER S.F. OHANNESIN UNIVERSITY OF WATERLOO M. VANDEGRIENDT WATERLOO, ONTARIO R.W. GILLHAM CANADA INSTITUTE FOR GROUNDWATER RESEARCH DEPARTMENT OF EARTH SCIENCES APRIL 1994 American Petroleum Institute API PUBLs4bOL 94 = 0732290 0533704 T5L FOREW
4、ORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFAC- TURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQU
5、IP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS. NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANU- FACTURE, SA
6、LE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV- ERED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CONTAINED IN ITU FOR INFRINGEMENT OF LETTERS PATENT. THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- Copyright O 1994 American Petroleum instiwie i API PUBL*4bOL 94 m 0732290 0533705
7、998 m ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATION OF TKIS REPORT: API STAFF CONTACT Roger Claff, Health and Environmental Sciences Department MEMBERS OF THE SOIL AND GROUNDWATER TECHNICAL TASK FORCE Doroth
8、y Keech, Chevron Oil Field Research Company Victor Kremesec, Amoco Corporation AI Liquori, Exxon Research and Engineering Company Eugene Mancini, ARCO William Rixey, Shell Development Company Ed Sudicky, Barbara Butler and Colin,Mayfield offered useful advice and support. Karen Berry-Spark and Lloyd
9、 Lemon designed the field experiment and carried it through the third sample event. L. Lemon continued to assist throughout the field experiment and data analysis. France Beaudet, Jeff Barbaro, Anika Bedard, Doris Dumas, Isabelle Derome, Rick Devlin, Paul Drake, Susan Hipkin, Pat McGuinness, Mette P
10、oulsen and Katherine O?Leary assisted with the field sampling. Ralph Dickhout, Shirley Chatten, Paul Drake and Tracy Fowler performed the laboratory analyses. Ken Skene assisted in data analysis and evaluation of the moment analysis method. Canadian Forces Base Borden allowed the work to proceed on
11、their Base. . III API PUBLX4601 94 = 0732290 0533706 824 TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY e5-1 1 . INTRODUCTION . 1-1 2 . THE BORDEN TEST SITE 2-1 2.1 Geology 2-3 2.2 Hydrogeology 2-3 2.3 Groundwater Geochemistry 2-5 2.4 Subsurface Microbiology 2-6 Spatial Distribution of Dissolved O
12、xygen . 2-7 3 . THE FIELD EXPERIMENT . 3-1 3.1 Injection Solutions . 3-1 3.2 Injection Well Configuration . 3-3 Solute Injection System . 3-5 3.4 Injection of the Solutes . 3-6 3.5 Results of Injection Monitoring 3-6 Multilevel Sampler Array 3-7 3.7 Monitoring Approach . 3-8 Collection and Analysis
13、of Water Samples . 3-10 3.9 Quality of the Solute Concentration Data 3-11 4 . DATA MANAGEMENT AND ANALYSIS . 4.1 4.1 Data Entry and Correction Procedures . 4-2 4.2 Evaluation of Plume Capture . 4-3 4.3 Depth Integration of Solute Concentrations . 4-5 4.4 Projection to a Regular Grid 4.6 4.5 Spatial
14、Moment Estimation . 4-6 4.6 Discussion of Sources of Error in Mass Estimation 4-7 2.5 3.3 3.6 3.8 API PUBL*4bOL 94 0732290 0533707 760 TABLE OF CONTENTS (continued) Page Section 5 . OVERVIEW OF SOLUTE BEHAVIOR . 5-1 5.1 Areal Distributions of Solute Mass . 5-1 5.2 Vertical Solute Concentration Distr
15、ibutions 5-19 5.3 Aquifer Layering and Solute Distribution 5-25 5.4 Summary and Discussion of Observations . 5-27 6 . TRANSPORT OF THE SOLUTES . 6-1 6.1 Horizontal Center of Mass Trajectories 6-1 6.2 Velocities of Plume Movement 6-3 6.3 Field Retardation 6-7 6.4 Laboratory Sorption Experiments 6-9 6
16、.5 Spatial Variance and Dispersion 6-11 6.6 Summary and Discussion of Solute Transport Findings . 7 . ESTIMATES OF SOLUTE MASS . 7-1 Estimates of Injected Mass 7.2 Mass Estimates for Sample Rounds . 7-2 7.3 Rates of Mass Loss . 7-16 7.4 Discussion of Mass Loss Findings . 7-18 LABORATORY BIOTRANSFORM
17、ATION STUDY 8-1 8.1 Experimental Approach and Design . 8-1 8.2 Interpretation of Microcosm Data 8-3 8.3 Biotransformation of the Monoaromatics . 8-4 8.4 Persistence and Impact of MTBE 8-6 8.5 Persistence and Impact of Methanol 8-7 9 . FIELD BIOTRANSFORMATION . 9-1 6-14 7.1 7-1 8 . 9.1 Oxygen and BTE
18、X Persistence 9-1 9.2 Oxygen and Methanol Persistence 9-7 9.3 Impact of Methanol on BTEX Persistence . 9-15 9.4 Comments on Field Biotransformation Findings . 9-17 API PUBL*4bOL 74 = O732290 0533708 bT7 TABLE OF CONTENTS (continued) Section Page 10 . CONCLUSIONS AND IMPLICATIONS . 10-1 10.1 General
19、Solute Flow . 10-1 10.2 Transport of the Organic Solutes . 10-1 10.3 Biotransformation of the Monoaromatics . 10-2 10.4 Fate and Impact of MTBE . 10-3 10.5 Fate and Impact of Methanol . 10-3 10.6 Extension of Findings to Other Hydrogeological Settings 10-4 REFERENCES . R- 1 A . B . C . D . E . F . G
20、 H . LIST OF APPENDICES The Field Injection . A-1 The Monitoring Network B-1 Sample Collection Procedures . C-1 Laboratory Analytical Procedures D-1 Surface II Parameters . E-1 Locations of Plume Cross Sections F-1 Transport and Fate Data . G-1 Laboratory Biotransformation Studies . Under Separate C
21、over API PUBLXYbOL 94 O732290 0533709 533 1.1 . 2.1 . 2.2 . 3.1 . 3.2 . 6.1 . 6.2 . 6.3 . 6.4 . 6.5 . 7.1 . 7.2 . 7.3 . 7.4 . 7.5 . 9.1 . 9.2 . LIST OF TABLES Page Hydrophobicity Parameters for the Solutes at 25C 1-3 Characteristics of the Borden Aquifer . 2-4 Chemistry of the Aerobic Zone of the Bo
22、rden Aquifer . 2-6 Average Solute Concentrations in the Injection Solutions (ma) 3-7 . 3-9 Horizontal Velocities of the Chloride Plumes (cdday) 6-6 Range of Average Field Retardation Factors Calculated for the Organic Solutes 6-8 Average Retardation Factors for the Organic Solutes from Day Retardati
23、on Factors Calculated from K. s 6-10 Dispersivities of Freyberg (1 986) and this Study 6-13 Estimates of Injected Mass (grams) . 7-1 Estimates of Total Chloride Mass for each Sample Time (kg) 7-3 Estimates of Total Oxygenate Mass for Each Sample Time Estimates of Total Mass for BTEX at each Sample T
24、ime First Order Mass Loss Rates (day“) Calculated for Day 6 through Day 476 7-17 Comparison of Lnitial Conditions for the Natural Gradient Tests of Berry-Spark et aL(1987) and this Study . 9-5 ComDarison of First Order Mass Loss Rates (day-) 9-7 Summary of Sampling Rounds 6 to 106 . 6-9 (kg) . 7-6 (
25、grams) 7-9 1i . .II API PUBL*4bOL 94 = 0732290 0533730 255 LIST OF FIGURES Figure Page 2-1. (a) Map of southern Ontario and the Great Lakes showing the location of CFB Borden; (b) Plan view of the test site in the Borden sand quarry showing the 1979 boundaries of the landfill leachate plume; (c) Sit
26、e cross section showing the 2-2. Longitudinal profiles of background dissolved oxygen 2-3. Transverse profile of background dissolved oxygen distribution 3-1. Plan view of the final array of multilevel samplers and 5-1. Contour plots of depth integrated chloride data for the first, 5-2. Contour plot
27、s of depth integrated MTBE and methanol data 5-3. Contour plots of depth integrated benzene data for the first, 5-4. Contour plots of depth integrated toluene data for the first, 5-5. Contour plots of depth integrated p-xylene data for the first, 5-6. Contour plots of depth integrated m-xylene data
28、for the first, 5-7. Profiles of chloride concentration along the centerline of the 5-8. Profiles of benzene, chloride, and methanol concentration along the centerline of the 85% methanol plume on Day 317 . 5-22 5-9. Profiles of toluene concentration along the centerline of the 5-10. Profiles of p-xy
29、lene concentration along the centerline of the 5-11. Profiles of hydraulic conductivity (after Pamck, 1986) and chloride, benzene, m-xylene, and dissolved oxygen injection zone (after Mackay et al., 1986) 2-2 distribution for the three injection zones. 2-8 at the three injection zones. 2-9 locations
30、 of the injection wells. . 3-4 third, fourth and sixth sample rounds . 5-3 for the first, third, fourth and sixth sample rounds 5-6 third, fourth and sixth sample rounds . 5-9 third, fourth and sixth sample rounds 5-12 third, fourth and sixth sample rounds 5-15 third, fourth and sixth sample rounds
31、5-17 85% methanol plume on Day 106 and Day 476 . 5-20 85% methanol plume on Day 106 and Day 398 . 5-23 85% methanol plume on Day 398 and Day 476 Concentration with depth at sampler #4A-N1 . 5-26 5-24 API PUBLX4601 94 m 0732290 0533711 191 m LIST OF FIGURES (continued) Figure Page 6-1. Center of mass
32、 trajectories for the chloride, toluene, and 6-2. Plot of distance traveled vs. time for solutes in the 100% PS-6 p-xylene plumes . 6-2 gasoline control plume . 6-4 6-3. Plots of distance traveled vs. time for solutes in the 10% MTBE and 85% methanol plumes . 6-5 6-4. Longitudinal and horizontal tra
33、nsverse variance for chloride in the 100% PS-6 gasoline control and the 85% methanol cases. . 6-12 7-1. Plots of mass vs. time for chloride in the 100% PS-6 gasoline control plume. . 7-3 7-2. Plots of mass vs. time for chloride in the 10% MTBE and 85% methanol plumes. . 7-5 7-3. Plots of mass vs. ti
34、me for MTBE and methanol. . 7-7 7-4. Plots of benzene mass vs. time for the 10% MTBE and 85% methanol plumes as compared to the 100% PS-6 control 7-10 7-5. Plots of ethylbenzene mass vs. time for the 10% MTBE and 85% methanol plumes as compared to the 100% PS-6 control . 7-1 1 7-6. Plots of p-xylene
35、 mass vs. time for the 10% MTBE and 85% methanol plumes as compared to the 100% PS-6 control 7-12 7-7. Plots of o-xylene mass vs. time for the 10% MTBE and 85% methanol plumes as compared to the 100% PS-6 control 7-1 3 7-8. Plots of toluene mass vs. time for the 10% MTBE and 85% methanol plumes as c
36、ompared to the 100% PS-6 control 7-14 7-9. Plots of m-xylene mass vs. time for the 10% MTBE and 85% 7-15 8-1. Conceptual illustration of relative concentration vs. time for benzene, toluene, and m-xylene in microcosms containing Borden aquifer material and groundwater contacted by 100% methanol plum
37、es as compared to the 100% PS-6 control PS-6 gasoline . 8-5 8-2. Persistence of MTBE in unlimited oxygen microcosms 8-7 Persistence of methanol in unlimited oxygen microcosms . 8-8 8-3. API PUBL*4603 94 0732290 0533732 O28 = LIST OF FIGURES (continued) Page Figure 9.1 . BTEX and dissolved oxygen dis
38、tributions in a transverse cross 9.2 . 9.3 . 9.4 . 9.5 . Methanol distributions along the plume centerline on Day 6 section through the three plumes at the fourth sample round . 9-3 Cumulative oxygen entry into the methanol plume Dissolved oxygen along the plume centerline: Day 106 . 9-11 Dissolved
39、oxygen along the plume centerline: Day 317 and Day 106 . 9-14 . 9-9 . 9-12 API PUBL*4bOL 94 0732290 O533733 Tb4 EXECUTIVE SUMMARY This report presents the results of a field investigation of the fate and transport of two gasoline additives, methanol and methyl tertiary butyl ether (MTBE), in groundw
40、ater and the influence of these compounds on the groundwater fate and transport of the gasoline constituents benzene, toluene, ethylbenzene, and xylene (BTEX). Related laboratory experiments which are the subject of a separate report are also summarized. BACKGROUND Oxygenates such as MTBE and methan
41、ol are added to gasoline to boost octane and/or to reduce air pollution from combustion. Research to date on the effects of gasoline spills to groundwater has focused on the behavior of BTEX, investigating the fate of these compounds in pure form or as constituents of non-oxygenated gasoline. Little
42、 is known about the effects of oxygenates on the migration and fate of BTEX in groundwater or the subsurface behavior of the oxygenates themselves. APPROACH The field experiment was conducted in a well characterized, unconfined, aerobic sand aquifer at Canadian Forces Base Borden, Ontario, Canada. T
43、he study was designed to compare and contrast the behavior of dissolved BTEX and oxygenates from simulated spills of three different types of motor fuels: (1) 100% gasoline, (2) 10% MTBE and 90% gasoline, and (3) 85% methanol and 15% gasoline. A key objective to facilitate data interpretation was to
44、 create three dissolved contaminant plumes of similar size that would travel side by side in the same flow system and geochemical environment with minimal lateral overlap. The plumes were created by simultaneously injecting below the water table solutions prepared by contacting extracted groundwater
45、 with a standard gasoline (PS-6) and diluting to obtain total dissolved BTEX concentrations of about 18 m i.e BTEX, were less mobile. The relative mobility of these monoaromatics was reflective ES-2 API PUBL*4bOL 94 D 0732290 0533735 837 D of their relative hydrophobic nature. Benzene was transporte
46、d at about 90% of the groundwater velocity, toluene at about 75%, and ethylbenzene and the xylene isomers moved at about 67% of the groundwater velocity. Neither MTBE or methanol caused a measurable difference in mobility of the monoaromatics relative to the control case. Persistence MTBE was recalc
47、itrant in the aquifer, exhibiting no mass loss over the sixteen month experiment. In contrast, methanol was rapidly degraded after an initial lag period of about 100 days. Less than one percent of the methanol mass remained by the final sampling event. The removal of methanol coincided with an enhan
48、ced depletion of oxygen within the boundaries of the 85% methanol/l5% gasoline plume relative to the control. Insufficient oxygen was available to account for all of the methanol loss, therefore the methanol is considered to have degraded by first aerobic, then anaerobic, biotransformation. The mono
49、aromatic hydrocarbons, BTEX, biodegraded in all three plumes. In each of the plumes, the relative rate of biodegradation was: toluene and m-xylene o- and p-xylene benzene. This reflects general agreement with other studies that indicate that in BTEX mixtures, toluene and xylenes are preferred substrates for microorganisms as compared to benzene. However, once toluene and xylene concentrations diminish, the rate of benzene degradation increases. MTBE had no measurable effect on the persistence (biodegradation) of the monoaromatics. Benzene, ethylbenzene, and p-xylene were mor
