UCRL-AR-135949 Vol. 4 Ch. 1

Volume 4: Potential Ground and Surface

Water Impacts

Chapter 1: Potential Scenarios for Ethanolcontaining Gasoline Released into Surface and

Subsurface Waters

Authors

David W. Rice1

Susan E. Powers2

Pedro J.J. Alvarez3

Editor

G. Cannon*

Contributor

R. Depue*

December 1999

1Corresponding Author

2Clarkson University, Potsdam, NY 13699

3University of Iowa, Iowa City, IA 52242

*Lawrence Livermore National Laboratory, Livermore, CA 94550

University of California • Livermore, CA 94550

Lawrence Livermore National Laboratories

 Environmental Restoration Division
Work performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National

Laboratory under Contract W-7405-Eng-48.
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Table of Contents

1. Potential Scenarios for Ethanol-containing Gasoline Released into Surface and

Subsurface Waters ................................................................................................................. 1-1

1.1. Introduction................................................................................................................... 1-1

1.2. Production..................................................................................................................... 1-1

1.2.1. Trace Compounds Introduced during the Production of Fuel-grade

Ethanol .............................................................................................................. 1-1

1.2.2. Additives........................................................................................................... 1-2

1.3. Distribution ................................................................................................................... 1-3

1.3.1. Distribution of Bulk Fuel Ethanol..................................................................... 1-3

1.3.2. Blending of Ethanol with Gasoline................................................................... 1-3

1.3.3. Transportation and Storage of Blended Gasohol.............................................. 1-4

1.4. Use ................................................................................................................................ 1-5

1.4.1. Present Extent of Gasohol Use ......................................................................... 1-5

1.4.2. Releases from Watercraft Exhaust Emissions into Surface Waters.................. 1-5

1.4.3. Releases from Washout of Tailpipe Automotive Emissions and

Combustion Products ot Surface Waters .......................................................... 1-6

1.5. Field Studies.................................................................................................................. 1-6

1.5.1. Bulk Fuel Ethanol Releases with Fuel Hydrocarbons Absent.......................... 1-6

1.5.2. Bulk Fuel Ethanol Releases with Fuel Hydrocarbons Present.......................... 1-7

1.5.3. Releases of Gasohol from Tanker Truck .......................................................... 1-8

1.5.4. Gasohol Releases from Gas Station Underground Storage Tanks.................... 1-8

1.5.5. Summary of Knowledge Gained from Field Studies........................................ 1-9

1.6. References..................................................................................................................... 1-9

List of Figures

Figure 1-11. Life-cycle of fuel ethanol..................................................................................... 1-15

List of Tables

Table 1-1. Life-cycle assessment of ethanol releases................................................................ 1-19

Table 1-2. Summary of fuel-grade alcohol at time of blending as specified by

ASTM specification D4806-95................................................................................ 1-24

Table 1-3. Trace compounds introduced during production of fuel-grade ethanol................... 1-24
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1. Potential Scenarios for Ethanolcontaining Gasoline Released into Surface

and Subsurface Waters

1.1. Introduction

If California introduces the use of ethanol as a fuel oxygenate, a variety of scenarios may be

anticipated in which either bulk fuel-grade ethanol or gasoline blended with ethanol (gasohol)

may be released into the environment during its production, distribution, and use. The purpose

of this chapter is to use a life-cycle approach (that is, the production, distribution, and use of

ethanol) to review systematically the potential release scenarios that may impact California’s

surface and subsurface waters. The discussion of these scenarios includes field studies wherever

possible to identify potential surface and groundwater impacts associated with a scenario.

Figure 1-1 summarizes the life-cycle phases of production storage, blending, distribution, and

use of ethanol and gasohol. Table 1-1 summarizes the various potential release scenarios. The

table includes a brief description of each release site assumptions and risk assessment issues that

may be important during the consideration of each scenario. Also included in the table are

qualitative descriptions of the likelihood of occurrence for the scenario, risk-management

options, and other release considerations.

1.2. Production

Currently, ethanol is produced primarily in the Midwest from domestic grain. (California has

the potential in the future to produce ethanol from recycled biomass [California Energy

Commission, 1999]). Most large ethanol producers use a process called “wet-milling” to

separate the starch from the grain prior to fermentation of the starch. The highly purified starch

is used as the feedstock for ethanol (American Coalition for Ethanol [ACE], 1999). Small

processors, however, still use whole-grain fermentation processing which does not first separate

out starch through wet-milling and leaves more impurities in the final ethanol product which are

not removed.

During the production of ethanol, bulk fuel-grade ethanol (that is, fuel ethanol) is typically

stored in large-capacity, above-ground storage tanks (ASTs). Bulk fuel ethanol releases from

ASTs and associated piping may also contain other compounds that are byproducts of the

fermentation and the subsequent distillation process, or that have been added as amendments.

1.2.1. Trace Compounds Introduced during the Production of

Fuel-grade Ethanol

1.2.1.1. Process Impurities

When purified starch is used to produce ethanol, the recovered bulk fuel ethanol is relatively

free of production byproducts except for glycerol and fusel oil. Glycerol is a major byproduct
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(about 5–10% of the quantity of ethanol) of fermentation (Karaosmanoglu et al., 1996); however,

glycerol has a boiling point higher than 200°C and is an unlikely contaminant in the final

distilled ethanol product.

Another byproduct of the industrial fermentation process is “fusel oil,” an alcohol mixture

with a boiling range of 80–132°C. The amount and the composition of fusel oil produced in the

fermentation process depend on the raw materials used. A typical fusel-oil production ratio

during the fermentation process is 0.2–0.7% (wt) on the basis of pure ethanol (Karaosmanoglu et

al., 1996). Although 50 different compounds have been identified in fusel oil, its major

components are fermentation amyl alcohols, such as 2-methyl-1-butanol and 3-methyl-1-butanol

(Karaosmanoglu et al., 1996).

There are also other compounds, such as acetaldehydes and ethyl acetate, present as process

impurities. However, the concentration of these byproducts in fuel ethanol is only in the

milligrams-per-liter (mg/L) range when purified starch is used as the feedstock.

Fuel ethanol produced from whole grain contains substantially more impurities

(Karaosmanoglu et al., 1996). These byproducts are derived from the non-starch portions of the

whole grains, such as hemicellulose and pectin, which contain methyl and acetyl groups. Upon

hydrolysis, methanol and acetic acid are formed. These byproducts are subsequently distilled

together with ethanol. Whole-grain processing also produces a higher quantity of fusel oil in fuel

ethanol. These byproducts are not separated out of fuel ethanol by distillation and so are

delivered with the final product.

Methanol is another common process impurity in fuel ethanol. Typically, fuel ethanol

consists of the following: 95.1 wt% ethanol, 4.8 wt% water, and 0.1 wt% higher alcohols (Paul,

1978). At the time of blending, fuel alcohol must meet the criteria in Table 1-2.

1.2.2. Additives

Denaturants—toxic or noxious materials used to make the ethanol unfit for human oral

consumption—must be added to fuel ethanol directed to storage. Commonly used denaturants

for fuel ethanol are unleaded gasoline or rubber hydrocarbon solvent. These are added to ethanol

at a minimum of 2% by volume, as defined by formula CDA 20 of the Bureau of Alcohol

Tobacco and Firearms of the U.S. Treasury Department (American Society of Testing and

Materials [ASTM], 1995). This specification prohibits the use of hydrocarbons, such as

kerosene, with a boiling point higher than 225°C. Thus, only hydrocarbons in the gasoline

boiling range can be used as denaturants (ASTM, 1995).

Denatured fuel ethanol may contain other additives, such as corrosion inhibitors and

detergents (ASTM, 1995). Various blending agents also have been used in fuel alcohol-gasoline

mixtures to lower the phase-separation temperature of the blends to below ambient temperatures

experienced during the winter season (Karaosmanoglu et al., 1996). These blending agents can

be grouped as aromatic compounds, higher aliphatic alcohols, and aromatic alcohols. The

addition of other materials is prohibited.

In the final product, the ethanol component of denatured fuel ethanol, excluding water, must

comprise at least 98% by volume and must not contain more than 0.5% by volume of methanol

or total ketones, or both. Furthermore, the total ethanol content of denatured fuel ethanol,

including impurities, must be no less than 95% by volume (ASTM, 1995). A summary of the
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trace compounds created or introduced during production and processing of fuel ethanol is

shown in Table 1-3. This table shows no additional trace elements that are noteworthy of

concern due to their solubility and associated toxicity compared to other common gasoline

components. None of these trace compounds is substantially less biodegradable than other

common gasoline components.

1.3. Distribution

1.3.1. Distribution of Bulk Fuel Ethanol

Shipments of ethanol to California could average about 46 million gal per month and could

be as high as 50 million gal per month during the summer peak driving season. A combination

of rail transport and marine cargo is likely to be used to distribute bulk ethanol to the California

market. Initially, approximately 80% of the bulk ethanol destined for California will be shipped

in railroad tanker cars that typically contain about 29,000 gal. Approximately 1600 rail car

movements per month would be needed to meet demand (Downstream Alternatives, Inc., 1999).

Strings of railroad tankers may be piped together to form a unit train “rolling pipeline.” This

arrangement allows a string of tanker cars to be emptied quickly, permitting transport turnaround

times of about two weeks between production facilities in the Midwest and distribution terminals

in California (Jaffoni, 1999).

Initially, about 20% of the bulk ethanol will be transported as marine cargo. In this scenario,

10,000-barrel tanker barges would float the bulk fuel ethanol down the Mississippi River to New

Orleans where it would then be transferred to large-capacity marine tankers for transport to

Pacific coast terminals. Marine tanker cargoes most likely would be about 4–5 million gal but

may be as large as 10–12 million gal (Downstream Alternatives, Inc., 1999; Jaffoni, 1999).

According to a California Energy Commission analysis (Schremp, 1999), two distribution

hubs—one in Northern California and one in Southern California—would receive the bulk fuel

ethanol. The volume of bulk fuel ethanol entering California as marine cargo is expected to

increase over time to as much as 80% because distribution terminals prefer receiving single

shipments of large quantities to minimize the labor- and time-intensive handling of rail cars

(Jaffoni, 1999).

Presently, refiners and pipeline operators are reluctant to distribute bulk fuel ethanol through

a pipeline because of concerns regarding ethanol’s affinity to water. Water is often present in

association with unblended gasoline transported through the pipelines (Center for Transportation

Research, no date). If this issue can be addressed, more pipeline use can be anticipated.

1.3.2. Blending of Ethanol with Gasoline

Because of the limitations in pipeline use, about 77% of the bulk fuel ethanol would be

distributed by tanker trucks from the distribution hubs to blending terminals. It is expected that

truck traffic would increase in proximity to the distribution hubs (Schremp, 1999). Pipelines will

continue to be used to deliver a base gasoline to blending terminals for blending with fuel

ethanol. The bulk fuel ethanol and base blending gasoline will be stored in separate tanks and

blended just prior to shipment to gas stations. Several blending processes are available

(Downstream Alternatives, Inc., 1999):
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• Tank Blending: This alternative requires a recirculation capacity within the storage

tank. This is the least preferred method because of the possibility of water contamination

of the blended fuel which may lead to separation during distribution.

• Top-off/Splash Blending: In this blending process, ethanol and base gasoline are

delivered separately into a tanker truck. The mixing during loading and transport

accomplish the blending process. This process is widely and successfully used and is the

preferred method for developing distribution systems.

• In-line/Injection Blending: Ethanol and gasoline are blended in-stream as the mixed

fuel is delivered to a tanker truck. This is the preferred method of blending for

established distribution systems because of better quality control and fewer blending

errors.

1.3.3. Transportation and Storage of Blended Gasohol

Tanker trucks will transport the gasohol (that is, gasoline blended with ethanol) much as it is

currently done. The typical gas station operates at least two underground storage tanks of

between 10,000 and 20,000 gal each. High-throughput gas stations may receive a tanker-truck

delivery at least once a day. If only two tanks are operated, mid-octane gas is often dispensed by

blending a lower- and a higher-octane gasoline at the pump.

Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and the three isomers

of xylene (BTEX) are ubiquitous groundwater pollutants commonly associated with petroleum

product releases from underground storage tanks (USTs). All six BTEX compounds are

powerful depressants to the central nervous system, and chronic benzene exposure can cause

leukemia (Federal Register, 1985). Thus, BTEX contamination of potential drinking water

sources represents a serious threat to public health. To put the magnitude of this problem in

perspective, 370,000 fuel releases from leaking underground storage tanks (LUST) have been

confirmed in the United States (U.S. Environmental Protection Agency [U.S. EPA], 1998). The

actual number of tank releases could be as high as 600,000 (Flatham, et al., 1994).

In December 1998 federal regulations were placed into effect requiring improved, leak

resistant underground gasoline storage tanks (Herman and Fields, 1998). California gas stations

are required to have USTs and piping that are double-walled with leak-detection systems capable

of detecting line leaks of 3 gal per hour and tank leaks of 3 gal per day (California Code of

Regulations, Title 23, sections 2610–2728).

Use of a 10% by volume (or less) ethanol blend requires no vehicle engine or fuel tank

modification (Canadian Renewable Fuels Association [CRFA], 1999). Currently, retail gasoline

dispensing equipment is designed to handle 10% by volume ethanol gasolines although attention

should be given to the use of alcohol-resistant materials in the pumps, line leak detectors, hoses,

seals, and nozzles (Center for Transportation, no date). Gas stations that convert to dispensing

gasohol will need to replace or recalibrate meters, conduct storage tank cleaning and drying, and

check storage tank and piping capability for use with ethanol fuels.
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1.4. Use

1.4.1. Present Extent of Gasohol Use

Gasohol has been used extensively in the corn-growing states of the Midwest for several

years. It can be found as an option at most gasoline stations in Iowa and Nebraska. At present,

60% of gasoline sold in Illinois and 90% of the gasoline sold in the Chicago area contains 10%

by volume ethanol (Renewable Fuels Association [RFA], 1999). Between the Chicago and

Milwaukee areas, approximately 450 million gal of ethanol are consumed in gasoline annually

(Hord, 1999). Gasohol has also been sold in Kansas through independent stations although its

availability has declined in the last couple of years because major distributors have bought many

of the independent stations (Winn, 1999). Throughout the United States, consumers use more

than 15 billion gal of ethanol-blended gasoline each year (ACE, 1999).

In July 1998, there were approximately 950 retailers of ethanol-blended fuels across Canada,

excluding those who were not listed with the CRFA (1999). The ethanol-gasolines were

distributed by most major petroleum companies (for example, Mohawk Oil; Sunoco, Inc., and

MacEwen Petroleum, Inc.) and several other independent retail outlets (Mr. Gas, Pioneer

Petroleum, Frances Fuels, Stinson Petroleum, and Sunys). This gasohol was available in all

grades of gasoline, and also for on-farm delivery.

During the use of gasohols in vehicles and watercraft, two types of emissions are released:

exhaust and evaporative. Exhaust emissions are those exiting the tailpipe during the combustion

of gasohols. Evaporative emissions occur while the vehicle is sitting as well as operating. Heat

from the engine or from ambient weather conditions can cause volatile components of the fuel,

including ethanol, to boil off and leak into the air. The California Air Resources Board has

developed emission profiles for proposed 5.8% and 10.1% ethanol blends of motor vehicle fuel

(Allen et al., 1999). These emission profiles have been used during our evaluation of potential

releases to groundwater from the rainout of these emissions.

Releases of ethanol and blended gasohol during production and distribution are typically

point source releases (that is, the extent of the release is a localized area). The environmental

concentrations of ethanol or gasoline components associated with point source releases often are,

initially, relatively high. On the other hand, the area extent of releases during the use of gasohol

is typically quite large, for example, an entire lake, watershed, or air basin. These types of

releases associated with the use of gasohol are referred to as non-point source releases, and the

environmental concentrations of ethanol and gasoline components associated with these types of

release typically are relatively low.

1.4.2. Releases from Watercraft Exhaust Emission into Surface

Waters

One of the unexpected surface-water impacts resulting from the use of MTBE in gasoline

was MTBE entering surface water in reservoirs and lakes in California (see Malcolm-Pirnie, Inc.,

1998; McCord and Schladow, 1998). The principal source of this contamination is recreational

boating, with the largest source attributed to two-stroke carbureted marine engines used in jet

skis (Allen et al., 1998). Recreational watercrafts typically discharge exhaust below the water
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surface. Often this discharge is through the watercraft propeller or propulsion jet, which

promotes a thorough mixing of the discharged compounds with surface waters.

Effective June 1, 1999, the Tahoe Regional Planning Agency imposed a ban on certain twostroke marine engine technologies. Previous studies had shown that while two-stroke carbureted

engines accounted for only 11–12% of the total fuel used by watercraft on Lake Tahoe, they

were responsible for approximately 90% of the MTBE emissions to the lake (Allen et al, 1998).

While recent data strongly suggests that the ban on certain types of two-stroke engines at Lake

Tahoe was very successful in reducing both MTBE and BTEX (Allen and Reuter, 1999:

Appendix C of Chapter 5 of this report), exhaust releases of gasoline containing ethanol can be

expected to continue.

1.4.3. Releases from Washout of Automotive Tailpipe Emissions

and Combustion Products to Surface Waters

Tailpipe and combustion products generally enter the atmosphere in the vapor phase. In the

case of ethanol and methyl tertiary butyl ether (MTBE), these vapors preferentially partition into

water present in the atmosphere. During precipitation events, such as rain storms or the

formation of dew, the ethanol or MTBE is washed out of the atmosphere and deposited onto the

ground surface or surface bodies of water and eventually infiltrates into groundwater. Although

the concentrations washed out often are relatively low, the depositions occur over a large area

and will continue to be deposited as long as the fuel is used. For these reasons, it is important to

consider any cumulative impacts that may result from the ongoing deposition of tailpipe

emissions and combustion products.

1.5. Field Studies

1.5.1. Bulk Fuel Ethanol Releases with Fuel Hydrocarbons

Absent

Releases of liquid bulk ethanol to soil and water can result from leaks or spills from ASTs at

the production site. Few studies have documented the release of bulk ethanol to soils where fuel

hydrocarbons are absent. Concentrations of ethanol as high as 2600 parts per million (ppm) were

detected at the site of a 30,000-gal spill of denatured alcohol (Chambers, 1999).

Although we found few field studies that deal with bulk releases at ethanol production sites,

there was a study of Savasol, a solvent comprised almost entirely of ethanol, that leaked from an

UST at an industrial facility in Salem, Massachusetts, in the early 1990s (Schaffner, 1999). The

volume of ethanol leaked was unknown. Although initial concentrations were high, ethanol

concentrations were non-detectable within six to eight months after the spill event. The

groundwater table was near the ground surface in the vicinity of the spill site. It is likely that

volatilization in combination with rapid biodegradation were important mechanisms in the rapid

natural attenuation of the bulk ethanol at this site.
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1.5.2. Bulk Fuel Ethanol Releases with Fuel Hydrocarbons

Present

A 1994 American Petroleum Institute (API) survey found that 85% of the monitored AST

farms reported groundwater contamination. In view of this fact, bulk ethanol releases at

distribution and blending terminals could reasonably be expected to impact already existing fuel

hydrocarbon releases. Indeed, as described below, there have been such incidents in states that

use gasohol.

Our review of field studies found a few instances in which ethanol was released at sites

where fuel hydrocarbons were known to be present. One such study concerned bulk ethanol that

was released in the early 1980s from a gasoline distribution terminal owned by Zephyr, Inc., in

Leelanau County, Michigan (Skipper, 1999). It is believed that the spill occurred when either a

valve or pipe failed during a transfer at the blending rack. The less-than-500-gal spill of ethanol

was onto soil which already had a high degree of prior contamination by other petroleum

hydrocarbons. Although the distribution of sampling wells at this site was sparse, groundwater

samples were analyzed for a very comprehensive suite of petroleum hydrocarbons. Technical

reports written about this site did not note any increase in the concentration of petroleum

hydrocarbons following the ethanol spill. The ethanol- and petroleum-contaminated soil has

since been excavated and landfilled, preventing any long-term analysis of the fate of these

contaminants.

An estimated 17,740 gal of denatured ethanol was released in September 1992 from an AST

at a bulk storage terminal in Tacoma, Washington (Hooton, 1999). The leak was attributed to a

faulty water draw valve. The area surrounding the spill site had previously been contaminated by

a variety of petroleum products. Free-product and groundwater recovery, and soil vapor

extraction remediation measures were ongoing at the site before the ethanol spill.

Groundwater and soil sampling efforts at the Tacoma, Washington, site were not initially

implemented due to the lack of regulatory concern by the Washington state Department of

Ecology (O’Hara, 1993). In August 1994—almost two years after the initial spill

event—groundwater samples were collected and analyzed for ethanol. Concentrations of ethanol

in the immediate vicinity of the tank that leaked ranged from 5,600 to 81,000 ppm (about 8%

ethanol by mass) (EMCON, 1997). However, no ethanol was detected in these same wells in

May 1997, approximately five years after the spill.

While data in this case are insufficient to thoroughly assess the overall impact of ethanol on

the existing light nonaqueous phase liquid (LNAPL) contamination, or benzene, toluene, ethyl

benzene, and xylene (BTEX) concentrations, evidence suggests that benzene concentrations

increased in the immediate vicinity of the tank as a result of high ethanol concentrations. Data

quantifying benzene concentrations before and after the ethanol spill are only available for one

well. Benzene concentrations two to five years after the spill (10–20 mg/L) were more than an

order of magnitude higher than that three years before the spill (0.88 mg/L) (Dalton, 1998).

Although the lack of data prevents a thorough analysis of the effects of ethanol, it can be

concluded that the area within 20 ft of the ethanol spill generally has significantly higher

benzene concentrations than at other areas at the bulk petroleum distribution terminal.

The impact of the ethanol spill on the distribution of light non-aqueous phase petroleum

hydrocarbons (free product) at the Tacoma, Washington, site is unclear. Professionals who have
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studied this site conflict in their assessment of the amount of free product at the site before the

ethanol spill (Dalton, 1998; EMCON, 1997). Because of these conflicting interpretations of the

initial conditions, changes in the nature of the free product cannot be quantified.

In March 1999, an unknown amount of ethanol was released from an AST at a bulk fuel

ethanol terminal in the Pacific Northwest where petroleum hydrocarbons were also present. The

volume of the bulk fuel ethanol released is estimated to be greater than 10,000 gal (Buscheck,

1999). Groundwater sampling data from this site is much more extensive than that available at

other sites. At least ten additional wells were installed to monitor the fate of ethanol and BTEX

at this site; however, analysis of the database of groundwater concentrations has not yet been

completed. Groundwater was sampled in June and August 1999, with additional rounds of

sampling possible in the near future. Shortly after the spill event, concentrations of ethanol in

the groundwater ranged from 0.2 to 20,000 mg/L. Preliminary interpretation suggests that by the

August 1999 sampling period, less than five months after the spill itself, ethanol concentrations

in the groundwater were below detection limits.

Significant petroleum contamination existed at this site prior to the ethanol spill. BTEX and

total petroleum hydrocarbons (TPH) had been detected in soil samples although no free product

had been observed in the immediate vicinity of the ethanol tank. Preliminary analysis of the

groundwater concentration data suggests that BTEX concentrations are on the order of a factor of

two greater than before the ethanol spill.

1.5.3. Releases of Gasohol from Tanker Truck

Recent spills of gasohol from tanker trucks are treated as emergency response actions and

generally the site of these spills receive no long-term environmental monitoring. Therefore,

there is little data about residual impacts from such releases.

1.5.4. Gasohol Releases from Gas Station Underground Storage

Tanks

With the current widespread use of gasohol, it is expected that there would be numerous

releases of gasohol from LUSTs. As part of the review conducted for this chapter, information

was gathered on the extent and knowledge base available about such sites. The data collection

methods included telephone interviews with state and US EPA personnel in Midwestern states

who investigate and remediate LUSTs, contact with Bruce Bauman of the API, and a general

request for information through an electronic mailing list to groundwater professionals.

From these contacts, it appears that there is inadequate information available to identify and

investigate the impact of ethanol on the fate of BTEX species from LUST sites at gasoline

stations. Although the persons who were interviewed acknowledged that there must be gasohol

spill sites in each of the Midwestern states, there is no knowledge base associated with potential

differences in the nature or extent of groundwater contaminated by gasohol versus gasolines not

containing ethanol.

David Chambers of the Nebraska Department of Environmental Quality (NDEQ) searched

the NDEQ database for spill sites related to “gasohol,” “alcohol,” or “ethanol” (Chambers,

1999). Of the 39 entries found, 11 were associated with gasohol or ethanol-diesel mixtures (see
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Appendix A for database search results). For the one railroad accident involving a 114,000-gal

alcohol diesel release, no ethanol was detected in the groundwater.

1.5.5. Summary of Knowledge Gained from Field Studies

In general, the information presently available on the fate of BTEX and ethanol at field sites

confirms the expected behavior based on the literature reviews presented in Chapters 2 and 3 of

this volume. Although the information is sparse, it appears that when neat ethanol is spilled, the

ethanol concentrations drop quickly in the subsurface via natural attenuation mechanisms. There

is, however, a risk of elevated BTEX concentrations in groundwater following the release of bulk

ethanol into soil previously contaminated with petroleum products. A significant opportunity

exists to learn more from the ethanol spill site in the Pacific Northwest. Substantial data was

collected in a timely fashion at that site and further analysis could prove extremely valuable. An

effort to rigorously interpret this data could lead to substantial improvements in our

understanding of the fate of ethanol and BTEX in the subsurface.

For gasohol spills or LUFT releases at gasoline stations, much of the lack of information

stems from the regulatory environment controlling the investigation and remediation of gasoline

leaks and spills. None of the states requires that ethanol concentrations be measured in

groundwater samples because ethanol is not a regulated pollutant. Similarly, databases used for

tracking release sites do not include a mechanism to identify or sort releases of gasohol versus

non-ethanol gasolines. This is due in part to the perception that there are no important

qualitative differences in environmental impact between the two types of gasoline. Further, there

is no means of ascertaining the type of gasoline released at many sites. Perhaps, as was the case

with MTBE less than a decade ago, regulators and groundwater professionals are not yet looking

for any impacts because they do not perceive nor systematically evaluated gasohol as having an

important effect on impacts due to groundwater contamination.

1.6. References

ACE (American Coalition for Ethanol) (1999). Ethanol information: How ethanol is made

(online). Available: <http://www.ethanol.org/ethanol_info.html>.

Allen, B. C., and J. E. Reuter (1999). Changes in MTBE and BTEX Concentrations in Lake

Tahoe, CA-NV, Following Implementation of a Ban on Selected 2-Stroke Marine Engines.

In Assessment of the Use of Ethanol as a Fuel Oxygenate, Vol 4: Potential Ground and

Surface Water Impacts, Vol 4 Ch 5, Appendix A. Lawrence Livermore National Laboratory,

Livermore, CA. UCRL-AR-135949.

Allen, B. C., J. E. Reuter, C. R. Goldman, M. F. Fiore, and G. C. Miller (1998). Lake Tahoe

motorized watercraft—an integration of water quality, watercraft use and ecotoxicology

issues. John Muir Institute for the Environment, University of California, Davis. 37 p.

Contribution #001-1998.

Allen, P., R. Bradley, B. E. Croes, J. DaMassa, R. Effa, M. Fuentes, D. Luo, R. Vincent,

L. Woodhouse, and E. Yang (1999). Analysis of the Air Quality Impacts of the Use of

Ethanol in Gasoline. California Air Resources Board, Sacramento, CA.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

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ASTM (American Society of Testing and Materials) (1995). Standard specification for denatured

fuel ethanol for blending with gasolines for use as automotive spark-ignition engine fuel.

D 4806-95a. American Society of Testing and Materials, Philadelphia, PA.

Buscheck, T. (1999). (Chevron Research and Technology Company). Personal Communication

with S. E. Powers, September 13.

California Energy Commission (1999). Evaluation of Biomass-to-Ethanol Fuel Potential in

California: A Report to the Governor and the Agency Secretary, California Environmental

Protection Agency (pdf online). In Ethanol-powered vehicles. Available:

<http://www.energy.ca.gov/afvs/index.html>.

California Code of Regulations, Title 23, sections 2610–2728, Underground Storage Tank

Regulations.

Center for Transportation Research, Argonne National Laboratory (No date). Guidebook for

Handling, Storing, and Dispensing Fuel Ethanol. Prepared for the U.S. Department of

Energy, Argonne National Laboratory, Chicago, IL.

Chambers, D. (1999). (Nebraska Department of Environmental Quality). Personal letter to S. E.

Powers, September 13.

CRFA (Canadian Renewable Fuels Association) (1999). Fact sheet: Questions and Answers on

ethanol (online). Available: <http://www.greenfuels.org/ethaques.html/>.

Dalton, M. (1998). (Dalton, Olmsted & Fuglevand, Inc.) Memorandum dated April 2 to

S. Hooton, BP Oil.

Downstream Alternatives, Inc. (1999). The Use of Ethanol in California Clean Burning

Gasoline: Ethanol Supply/Demand and Logistics. Report prepared for the Renewable Fuels

Association by Downstream Alternatives Inc., Breman, IN.

EMCON (1997). Letter report dated September 5 from Michael D. Stalton to Cherine Foutch,

Mobile Oil Corporation.

Federal Register (1985). U.S. Government Printing Office, Washington, DC, November 13.

Flatham, P. E., D. E. Jerger, and J. H. Exner (1994). Bioremediation Field Experience. Lewis

Publishers. Ann Arbor, MI.

Herman, S. A. and T. J. Fields (1998). Supplemental information regarding the August 10, 1998

enforcement strategy to EPA. December 9.

Hooton, S. T. (1999). (BP Amoco) Personal communication with S. E. Powers, September 3.

Hord, B. (1999). Ethanol’s future may boom or bust. Omaha World Herald, Omaha, NE.

Monday, June 28.

Jaffoni, F. T. (1999). Viability of ethanol as an oxygenate alternative to MTBE: Supply,

distribution, cost, and environmental impact. Presented to the HART/IRI World Fuels

Conference, Washington, DC, October 1.

Karaosmanoglu, F., A. Isigigur, and H. Ayse Aksoy (1996). Effects of a new blending agent on

ethanol-gasoline fuels. Energy & Fuels 10: 816-820.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-11

Malcolm Pirnie, Inc. (1998). Evaluation of the Fate and Transport of Ethanol in the

Environment. Report prepared for the American Methanol Institute, Washington DC.

Malcolm Pirnie, Inc., Oakland, CA. November. Report No. 3522–001.

McCord, S. A., and S. G. Schladow (1998). Transport and Fate Modeling of MTBE in Lakes and

Reservoirs. In Health & Environmental Assessment of MTBE, Report to the Governor and

Legislature of the State of California as Sponsored by SB 521, Volume IV: Ground and

Surface Water. November. Available: <http://tsrtp.ucdavis.edu/mtberpt/vol4_4.pdf>

O’Hara, R. J. (1993). (BP Oil) Letter dated August 16 to Ms. Cherine Foutch, Mobile Oil

Corporation.

Paul, J. (1978). Methanol Technology and Application in Motor Fuel. Noyes Data, Park Ridge,

NJ.

RFA Available (Renewable Fuels Association) (1999). Governors send strong message to EPA:

Preserve ethanol’s role in RFG. Ethanol Report (pdf online). Issue 89. February 11.

<http://www.ethanolRFA.org/EReports/er021199.html>

Schaffner, I. R., Jr. (1999). (GZA GeoEnvironmental) Personal communication with

S. E. Powers, September 3.

Schermp, G. (1999). MTBE phaseout: Ethanol logistics and unresolved issues. Presentation to

Department of Energy Ethanol Workshop, October 5.

Skipper, J. (1999). (Michigan Department of Environmental Quality) Personal communication

with S. E. Powers, September 3.

US EPA (U.S. Environmental Protection Agency) (1998). Corrective action measures.

September 30, 1998.

Winn, T. (1999). (Kansas Department of Health and the Environment). Personal communication

between T. Winn and S. E. Powers, August 27.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-12
UCRL-AR-135949 Vol. 4 Ch. 1

12-99/Ethanol Ch. 1:rtd 1-13

Figures
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-14
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-15

Figure 1-1. Life-cycle of fuel ethanol.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-16
UCRL-AR-135949 Vol. 4 Ch. 1

12-99/Ethanol Ch. 1:rtd 1-17

Tables
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-18
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-19

Table 1-1. Life-cycle assessment of ethanol releases.

Release scenario Release assumptions Site assumptions

Likelihood of

occurrence

Risk

assessment issues

Risk

management options

Production

Release from an

aboveground storage

tank (AST) at

production site

Assumes a largevolume (>30,000 gal)

bulk ethanol release

to soils and

groundwater from a

high-volume AST or

associated piping at

an ethanolmanufacturing site.

Assumes bulk ethanol

release into relatively

pristine subsurface

conditions. Fuel

hydrocarbons are

assumed to be

historically absent.

Small likelihood of

occurrence.

Because California

currently has few

ethanol production

facilities, this scenario

represents a release

that could occur only

once biomass ethanol

production facilities

are constructed in the

state in the future.

Toxicity to ecological

receptors in direct

contact with the

release. Case studies

indicate that ethanol

is relatively rapidly

lost in the subsurface

environment.

Engineered

containment to

control potential

release, e.g., doublewalled tanks and

piping. Spill

prevention and

containment

contingency (SPCC)

Plans typically in

place.

Distribution

Release during bulk

ethanol transport by

rail or highway

Assumes that a

rupture of a rail tank

car or a tanker truck

releases a large

volume of bulk

ethanol (10,000–

30,000 gal) to soils

and groundwaters or

surface waters.

Assumes a relatively

pristine surface and

subsurface conditions

where fuel

hydrocarbons are

historically absent.

Moderate likelihood

of occurrence.

Because California

currently has few

ethanol production

facilities, most

ethanol used will

initially be imported

into the state by way

of rail tank car or

tanker truck.

Toxicity to ecological

receptors in direct

contact with the

release. Potential to

impact surface

aquatic ecosystem. It

is likely that

volatilization as well

as biodegradation

will be important

mechanisms in the

rapid natural

attenuation of the

bulk ethanol.

Rail car and truck

tanker releases are

typically treated as an

emergency response

action and generally

require no long-term

monitoring.
UCRL-AR-135949 Vol. 4 Ch. 1 DR Potential Ground and Surface Water Impacts December 1999

Table 1-1. Life-cycle assessment of ethanol releases (Cont.).

Release scenario Release assumptions Site assumptions

Likelihood of

occurrence

Risk

assessment issues

Risk

management options

12-99/Ethanol Ch. 1:rtd 1-20

Distribution (Cont.)

Release during bulk

ethanol transport by

marine cargo tanker

Assumes that a

rupture of a marine

tanker ship releases a

large volume of bulk

ethanol (>100,000 gal)

into marine surface

waters. While

ethanol is infinitely

soluble, it will tend to

distribute near the

water surface because

it is less dense than

water.

Assumes a bulk

ethanol release into

the near-shore coastal

marine environment.

Low likelihood of

occurrence.

However, the

shipment of ethanol

as marine cargo will

increase because

distribution hubs will

prefer to receive

larger quantities to

minimize the

handling of rail cars.

Toxicity to ecological

receptors in direct

contact with the

release; potential to

impact surface

aquatic ecosystem. It

is likely that

volatilization,

dispersion, and

dilution as well as

biodegradation will

be important

mechanisms in the

rapid natural

attenuation of the

bulk ethanol.

Requires bulk ethanol

to be shipped in

marine tankers with

double-walled

construction.

Release of bulk

ethanol at a

distribution terminal

Assumes a large

volume bulk ethanol

release to soils and

groundwater at a

distribution hub or

terminal. The release

is assumed to be from

a high volume AST or

associated piping.

ASTs at a distribution

hub may contain

>150,000 barrels of

ethanol.

Fuel hydrocarbons

are assumed to be

historically present

and may be present as

free product trapped

in the subsurface.

MTBE may be present

in the free product.

Moderate likelihood

of occurrence.

The ethanol is

assumed to interact

with soils

contaminated with

existing fuel

hydrocarbons.

Previously immobile

hydrocarbons may

now be mobilized to

the groundwater. An

existing fuel

hydrocarbon

groundwater plume

may be expanded.

Engineered

containment to

control release, e.g.

double-walled tanks

and piping. SPCC

Plans typically in

place. Manage the

location of ethanol

ASTs to avoid known

areas of fuel

hydrocarbon releases.

Remediate the fuel

hydrocarbon releases.
UCRL-AR-135949 Vol. 4 Ch. 1 DR Potential Ground and Surface Water Impacts December 1999

Table 1-1. Life-cycle assessment of ethanol releases (Cont.).

Release scenario Release assumptions Site assumptions

Likelihood of

occurrence

Risk

assessment issues

Risk

management options

12-99/Ethanol Ch. 1:rtd 1-21

Distribution (Cont.)

Release of blended

gasohol during

transport from a

California

distribution terminal

Assumes that ethanol

is blended with

gasoline at a

distribution terminal

or refinery and

transported by tanker

truck to a gas station.

Assumes a large

volume (~5000 gal) of

blended gasoline/

ethanol (10% or 6%

gasohol) released

from tanker truck to

soils and

groundwaters or

surface waters.

Assumes release

occurs into roadside

environments where

fuel hydrocarbons are

historically absent.

Moderate likelihood

of occurrence.

If any gasohol

infiltrates into the

subsurface, it will act

as a source of

groundwater

contamination.

Concentrations of

BTEX in groundwater

may initially be

somewhat higher

than for standard

gasoline spill.

Potential for a release

to streets and urban

storm drains.

Tanker cars and truck

releases are typically

treated as an

emergency response

action and generally

require no long-term

monitoring

Release at gas station

during underground

storage tank (UST)

filling

Assumes that gasohol

is spilled during UST

filling at a gas station.

A low-volume (< 50

gal) of blended

gasoline/ethanol

(10% or 6% gasohol)

released to soils and

groundwater.

Assumes small

masses of fuel

hydrocarbons are

historically present in

the subsurface.

A likely and common

release scenario.

The ethanol is

assumed to interact

with soils

contaminated with

existing fuel

hydrocarbons. MTBE

may be present.

UST over-fill buckets

associated with

upgraded USTs

should minimize

these releases.
UCRL-AR-135949 Vol. 4 Ch. 1 DR Potential Ground and Surface Water Impacts December 1999

Table 1-1. Life-cycle assessment of ethanol releases (Cont.).

Release scenario Release assumptions Site assumptions

Likelihood of

occurrence

Risk

assessment issues

Risk

management options

12-99/Ethanol Ch. 1:rtd 1-22

Distribution (Cont.)

Release at a gas

station from a small

UST puncture

Assumes a small

puncture of the UST

or associated piping

resulting in a lowvolume release of

blended gasohol

(~<3 gal per day).

Assumes release may

occur into sub-surface

environ-ments with

or without historic

fuel hydrocarbon

contamination.

MTBE may be

present.

A likely and common

release scenario.

Evaluation of this

scenario will be

important to

estimating potential

impacts to

groundwater

resources.

This scenario has the

potential to release a

large cumulative

mass of gasohol

because of the large

number of USTs in

operation and the

potential for small

leaks to go

undetected.

Current requirement

for USTs to use

double-walled

containment reduce

the likelihood of this

scenario’s occurrence.

There remain some

issues with materials

compatibility with

ethanol.

Release at a gas

station from large

UST puncture

Assumes a large

puncture of the UST

or associated piping

resulting in a highvolume release of

blended gasohol

(~<10 gal per day).

Assumes releases

may occur into

subsurface

environments with or

without historic fuel

hydrocarbon

contamination. MTBE

may be present.

Moderate likelihood

of occurrence.

Typically, larger UST

leaks are rapidly

detected, and

corrective action is

initiated.

Current requirement

for USTs to use

double-walled

containment reduce

the likelihood of

occurrence. Some

issues with materials

compatibility with

ethanol remain.
UCRL-AR-135949 Vol. 4 Ch. 1 DR Potential Ground and Surface Water Impacts December 1999

Table 1-1. Life-cycle assessment of ethanol releases (Cont.).

Release scenario Release assumptions Site assumptions

Likelihood of

occurrence

Risk

assessment issues

Risk

management options

12-99/Ethanol Ch. 1:rtd 1-23

Use

Release from

watercraft emissions

into surface waters.

Assumes a significant

percentage of fuel

released through

exhaust as

uncombusted free

product.

Assumes pristine

freshwater lakes and

rivers.

A likely and common

release scenario

The biodegradation

and volatilization of

ethanol in surface

waters is expected to

be rapid. Low

increases in nutrient

loading and decreases

in dissolved oxygen

concentrations may

occur.

Increase engine

combustion

efficiency.

Release due to rainout

of tailpipe emissions

and combustion

products to surface

soils and waters.

Assumes ethanol

vapors and

combustion products

will partition into

atmospheric

moisture.

Assumes widespread

nonpoint source

deposition with

various amounts of

recharge to

groundwaters and

runoff to surface

waters.

A likely and common

release scenario.

Ethanol emissions

preferentially

partitions into water

and will be expected

to rainout. The

biodegradation of

ethanol in surface

waters is expected to

be rapid.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-24

Table 1-2. Summary of fuel-grade alcohol at time of blending as specified by ASTM

Specification D4806-95.a

Description of trace compound Maximum content

Water content, max, mass % 1.25

Existent gum, max, mg/100 mL 5

Chloride ion content, max, mass ppm 40

Copper content, max, mg/kg 0.1

Acidity (as acetic acid), max, mass % 0.007

Appearance Visibly free of suspended or precipitated

contaminants (clear and bright)

a Source: American Society of Testing and Materials (ASTM), 1995.

Table 1-3. Trace compounds introduced during production of fuel-grade ethanol.a

Impurities Denaturants Blending agents Additives

Methanol

Fusel oil: amyl and

isoamyl alcohols

Unleaded gasoline

Rubber hydrocarbon

solvent; hydrocarbons

with end boiling point

<225°C (437°F)

Aromatic compounds

Aromatic alcohols

Higher alcohols

Corrosion inhibitors

Detergents

a The total content of impurities, denaturants, blending agents, water, and additives must be less than 5% (by

volume) of fuel alcohol (ASTM, 1995).
UCRL-AR-135949 Vol. 4 Ch. 1

12-99/Ethanol Ch. 1:rtd A-i

Appendix A

Results of Search of NDEQ Spill Database
UCRL-AR-135949 Vol. 4 Ch. 2 Potential Ground and Surface Water Impacts, EPA December 1999

12-99/Ethanol Ch. 1:rtd A-ii
UCRL-AR-135949 Vol. 4 Ch. 1 DR Potential Ground and Surface Water Impacts, EPA December 1999

12-99/Ethanol Ch. 1:rtd A-iii

Appendix A

Results of Search of NDEQ Spill Database1

 

1

 Provided by David Chambers, NDEQ (Chambers, 1999).
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts, EPA December 1999

12-99/Ethanol Ch. 1:rtd A-iv

Reference

Chambers, D. (1999). (Nebraska Department of Environmental Quality). Personal letter to S. E.

Powers, September 13.
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-20
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12-99/Ethanol Ch. 1:rtd 1-21
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-22
UCRL-AR-135949 Vol. 4 Ch. 1 Potential Ground and Surface Water Impacts December 1999

12-99/Ethanol Ch. 1:rtd 1-23
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12-99/Ethanol Ch. 1:rtd 1-24

Table 1-2 & 3