Technical Review of

Ethylene Glycol monoButyl Ether (EGBE):

Chemistry, Environmental Fate and Ecological Toxicity

CAS Registry Number 111-76-2

September 9, 2009

Office of Environmental Information

Office of Information Access and Analysis

Environmental Analysis Division

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460
Table of Contents

Chapter One – Chemistry and Environmental Fate............................................. 1

1.1 Summary................................................................................ 1

1.2 Synonyms/Identification.............................................................. 3

1.3 Physical and Chemical Properties................................................... 4

1.4 Production Methods................................................................... 5

1.5 Use Properties.......................................................................... 5

1.6 Environmental Fate..................................................................... 6

1.6.1 Environmental Transport................................................... 6

1.6.2 Abiotic Degradation........................................................ 7

1.6.3 Biotic Degradation......................................................... 8

1.6.4 Environmental Distribution............................................... 9

1.6.5 Toxic Transformation Products Assessment........................... 10

1.7 References............................................................................... 11

Chapter Two – Ecological Hazard Assessment................................................ 15

2.1 Summary............................................................................... 15

2.2 Ecological Toxicity................................................................... 15

2.2.1 Acute Toxicity............................................................... 19

2.2.2 Chronic Toxicity............................................................ 20

2.2.3 Terrestrial Toxicity and Phytotoxicity................................... 20

2.2.4 Population Effects.......................................................... 21

2.2.5 Bioaccumulation Potential................................................ 21

2.3 References.............................................................................. 21
1

CHAPTER ONE 

CHEMISTRY AND ENVIRONMENTAL FATE

O

HO

CH3

1.1. SUMMARY 

Ethylene glycol monobutyl ether (EGBE) (CAS Registry No. 111-76-2) is a member of 

the glycol ethers chemical class. The technical-grade product is a clear, combustible liquid with 

a mild ether odor (Dow, 2006). The molecular formula is C6H14O2 and the molecular weight is 

118.2. EGBE is described as miscible in water (Stoye and Aktiengesellschaft, 2005). It is also 

miscible with mineral oil and most organic solvents (O'Neil, 2006). EGBE's major use is as an 

ingredient in many coating formulations, inks, and cleaning formulations (Dow, 1990).

The major use of EGBE is as an ingredient in both solvent and water based coating 

formulations such as emulsions, dispersions, varnishes, enamels, and lacquers (Dow, 1990, 

2006). It is used as an ingredient in many cleaning formulations including household/industrial 

cleaners, liquid soaps, dry cleaning soaps, rug cleaners, spotting fluids, phosphoric acid rust 

removers, aluminum brighteners, metal cleaners, carbon and grease removers, 

paint/varnish/silicone removers, ink removers, hard surface cleaners, white wall tire cleaners, 

and disinfectants/germicides (Dow, 1990). 

EGBE is produced through the reaction of ethylene oxide with n-butanol in the presence 

of a catalyst (Dow, 1990, 2006). According to industrial reports provided to the U.S. 

Environmental Protection Agency (U.S. EPA) under the Inventory Update Rule (U.S. EPA, 

2007), EGBE has had a production volume of 100 million to 500 million pounds per year during 

reporting years 1986, 1990, 1994, 1998, and 2002. The reported U.S. production capacity for 

glycol ethers in 2007 was 1,623 million pounds (SRI, 2007). 
2

In 2007, releases of glycol ethers reported to the Toxic Release Inventory (TRI) (U.S. 

EPA, 2009) under the “certain glycol ethers” category totaled approximately 18,476,000 pounds. 

Reported releases to air, surface water, and land were approximately 16,416,000, 87,000, and 

1,311,000 pounds, respectively. Approximately 126,000 pounds were released via underground 

injection. Approximately 7,902,000 pounds were transferred to publicly-owned treatment works 

(POTWs). EGBE is one of the glycol ethers reportable under the “certain glycol ethers” 

category (specific release information for EGBE is not available in the TRI database). It is not 

known how much of these amounts are attributable to EGBE releases; however, this may be a 

large percentage since EGBE is the single most widely produced glycol ether (Dow, 2006). 

EGBE is expected to volatilize slowly into the atmosphere from terrestrial and aquatic 

surfaces based on its Henry’s law constant and a classification scheme (HSDB, 2007; Kim et al. 

2000; Lyman, 1990). Estimated volatilization half-lives of EGBE are 17 days for a model river 

and 185 days for a model lake (U.S. EPA 2008). When EGBE does volatilize, it is expected to 

exist primarily as a vapor in the atmosphere (EPI Suite, 2007; Bidleman, 1988). EGBE released 

to soils and sediments is not expected to strongly absorb and has the potential to migrate into

underlying groundwater systems (Hansch et al., 1995; HSDB, 2007; Staples et al., 1998; 

U.S.EPA, 2008). 

For EGBE in the atmosphere, the predicted half-life for the indirect photodegradation of 

this substance is 9.2 hours due to reaction with hydroxyl radicals (Atkinson, 1989; Leifer, 1993). 

EGBE may contribute to the formation of tropospheric ozone (Derwent et al., 1996; U.S. EPA, 

2006). Atmospheric degradation products can result in the formation of 2-butoxyacetic acid

(BAA) (see section 1.6.5) as well as peroxyacyl nitrates, (Atkinson, 2000; LOOP, 2003). In 

mammals 2-butoxyacetic acid is thought to be responsible for EGBE’s toxic hematological 

effects (U.S. EPA, 1999). Peroxyacyl nitrates (PAN) have been reported to be eye irritants, 
3

mutagenic, phytotoxic, and possible agents of skin cancer (Singh and Salas, 1989; Williams et al. 

1993). PAN has been shown to be mutagenic in Salmonella and in the lungs of mice exposed 

nose-only to PAN generated from non-mutagenic precursors (DeMarini et al., 2000). 

Based upon a level III fugacity model calculation (see Section 2.6.4), soil and water are the 

environmental compartments where the largest mass of EGBE will distribute, assuming equal 

releases of EGBE to air, water, and soil (U.S. EPA, 2008). Limited biodegradation data are 

available for this substance; however, EGBE is considered to be readily biodegradadable in soil 

and water based on screening level test data (CITI, 1992; Devillers et al., 2001; NITE 2002; 

OECD, 1997; Staples et al., 1998; Price et al., 1974; Waggy et al., 1994). EGBE is expected to 

be highly mobile in soil, and has the potential to move from soil to groundwater (HSDB 2007; 

Staples et al., 1998). 

The chemistry and environmental fate of EGBE are discussed in this chapter. Synonym 

and physical-chemical property information was obtained during a search of the on-line source 

ChemID Plus Advanced, handbook references, the Syracuse Research Corporation (SRC) 

PHYSPROP database, and the SRC Environmental Fate Data Base. Manufacturing and use 

information was obtained from the Ullmann's encyclopedia article on solvents (Stoye and 

Aktiengesellschaft, 2005) and the Glycol Ethers Handbook published by Dow Chemical 

Company (1990). Environmental fate data were obtained through a search of the literature 

compiled in SRC's Environmental Fate Data Base, the Hazardous Substances Data Bank (HSDB) 

record for EGBE (available on-line), and estimations performed using the EPI Suite v4.00

software.

1.2. SYNONYMS/IDENTIFIERS 

(CAS Registry, 2007; ChemID Plus Advanced, 2007):

Butoxyethanol
4

2-Butoxy-1-ethanol

2-Butoxyethanol

2-n-Butoxyethanol

3-Oxa-1-heptanol

Butyl Cellosolve

Butyl glycol

Butyl monoether glycol

Butyl oxitol

Dowanol EB

EGBE

Ethanol, 2-butoxy

Ethylene glycol butyl ether

Ethylene glycol monobutyl ether

Ethylene glycol n-butyl ether

Glycol butyl ether

Monobutyl glycol ether

1.3. PHYSICAL AND CHEMICAL PROPERTIES

Table 1-1 provides selected chemical and physical properties for EGBE.

Table 1-1. Physical and Chemical Properties of Ethylene glycol monobutyl ether (EGBE) (CAS 

Reg. No. 111-76-2)

Property Valuea Conditions Reference

Molecular formula C6H14O2 - O’Neil, 2006

Molecular weight 118.18 - O’Neil, 2006

Melting point (°C) -74.8 - Lide, 2005

Boiling point (°C) 171-172 - O'Neil, 2006

Vapor pressure (mm Hg) 0.88 25 °C Dow, 1990

Water solubility (mg/L) Infinite - Riddick et al., 1986

Log Kow 0.83 - Hansch et al., 1995

Henry’s law constant (atmm3

/mol)

8.16×10-725 °C Kim et al. 2000

Hydroxyl radical reaction rate 

constant (cm3/molec-sec)

1.4×10-11 25 °C Atkinson, 1989

Density (g/cm3) 0.9015 20 °C Lide, 2005

Flash Point (°C) 60 closed cup O'Neil, 2006

Autoignition temperature (°C) 244 - Lewis, 2001

aValues are experimental unless otherwise indicated.
5

1.4. PRODUCTION METHODS

According to Dow Chemical Company (1990, 2006), EGBE is produced via the reaction 

of ethylene oxide with n-butanol in the presence of a catalyst. Di- and tri-ethylene glycol 

monoethers are also produced in this reaction if the ratio of ethylene oxide to n-butanol is greater 

than 1. 

1.5. USE PROPERTIES 

EGBE is miscible with water and most organic solvents (O'Neil, 2006; Stoye and 

Aktiengesellschaft, 2005). It is used as a solvent for cellulose nitrate, cellulose ethers, 

colophony, shellac, chlorinated rubber, polyacrylates, polymethacrylates, alkyd resins, 

formaldehyde resins, synthetic resins, oils, and fats (Stoye and Aktiengesellschaft, 2005). The 

major use of EGBE is as an ingredient in both solvent and water based coating formulations such 

as emulsions, dispersions, varnishes, enamels, and lacquers (Dow, 1990, 2006). It serves as a 

solvent, a coalescent, or a coupling agent in these coatings which are designed for automotive, 

industrial, metal coil, architectural, and wood surfaces (Dow, 1990). EGBE is used as a solvent 

in gravure, flexographic, and silk screen inks and as a reactive diluent in radiation curable inks 

(Dow, 1990). EGBE is an ingredient in many cleaning formulations including 

household/industrial cleaners, liquid soaps, dry cleaning soaps, rug cleaners, spotting fluids, 

phosphoric acid rust removers, aluminum brighteners, metal cleaners, carbon and grease 

removers, paint/varnish/silicone removers, ink removers, hard surface cleaners, white wall tire 

cleaners, and disinfectants/germicides (Dow, 1990). EGBE has also been used in the 

manufacture of plasticizers (Dow, 1990). According to Dow Chemical Company (2006), 

relative percentages of the different market applications for EGBE are as follows: paints, 

coatings, and inks (53%), metal cleaning and household cleaning (15%), raw material for the 
6

production of 2-butoxyethyl acetate (5%), raw material for production of other chemicals (5%), 

other uses (21%). 

1.6. ENVIRONMENTAL FATE

1.6.1. Environmental Transport. 

EGBE is expected to volatilize slowly from moist soil and water surfaces, based on a 

Henry's law constant of 8.16×10-7atm-m3/mol at 25 °C and a classification scheme (HSDB, 

2007; Kim et al. 2000; Lyman et al., 1990). Using this Henry's law constant and the EPI Suite

estimation software (U.S. EPA, 2008), the volatilization half-lives of EGBE are calculated to be 

33 days for a model river1and 360 days for a model lake2. A vapor pressure of 0.88 mm Hg at 

25 °C (Dow, 1990) indicates that EGBE will volatilize slowly from dry soil surfaces (HSDB, 

2007). Using this vapor pressure value, a calculated particle/gas partition coefficient of 

2.05×10-6indicates that any EGBE that is released into the air will exist primarily as a vapor 

(Bidleman, 1988; U.S. EPA, 2008). Based on a bioconcentration factor (BCF) value of 3, 

calculated using regression-derived equations and the experimental log Kow value, EGBE is not 

expected to bioaccumulate in aquatic organisms. (Hansch et al., 1995; HSDB, 2007; Meylan, 

1999; Staples et al., 1998). Based on a Koc value of 67, calculated using regression derived 

equations and the experimental log Kow value, EGBE is not expected to adsorb strongly to soils 

and sediments and will have high mobility in soil and the potential to move from soil to 

groundwater (Hansch et al., 1995; HSDB, 2007; Staples et al., 1998; U.S.EPA, 2008). 

Additional data regarding the transport of EGBE through soil, surface water, and groundwater 

have not been located in the available literature.

 

1 Parameters for the model river are 1 m deep, flowing 1 m/sec, wind velocity of 5 m/sec.

2 Parameters for the model lake are 1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec.
7

1.6.2. Abiotic Degradation. 

EGBE is not expected to undergo direct photolysis since it does not absorb radiation in 

the environmentally available region of the electromagnetic spectrum that has the potential to 

cause molecular degradation (HSDB, 2007). EGBE will be degraded in the atmosphere by 

reaction with photochemically produced hydroxyl radicals. Atkinson (1989) has reported a 

measured rate constant of 1.4×10-11 cm3/molecule-sec at 25 °C for this reaction, which 

corresponds to a half-life of 9.2 hours assuming an atmospheric hydroxyl radical concentration 

of 1.5×106 molecules/cm3and a 12-hour day (Leifer, 1993). Stemmler et al. (1997) and Tuazon 

et al. (1998) reported that three formate esters, two aldehydes, and one organic nitrate were the 

major products of EGBE atmospheric photooxidation: butyl formate, 2-hydroxyethyl formate, 3-

hydroxybutyl formate, butoxyacetaldehyde, propionaldehyde, and the organic nitrate 

CH3CH2CH2CH2OCH(ONO2)CH2OH. 

In the atmosphere, aldehydes react with photochemically produced hydroxy radicals to 

form acyl peroxy radicals (Atkinson, 2000). In the presence of O2 and NO2, acyl peroxy radicals 

undergo transformation to form peroxyacyl nitrates, which are analogs of peroxyacetyl nitrate 

(PAN) (Atkinson, 2000; LOOP, 2003). Following this mechanism, atmospheric photooxidation 

of butoxyacetaldehyde and propionaldehyde can result in the formation of peroxybutoxyacetyl 

nitrate and peroxypropionyl nitrate (PPN), respectively.

With a vapor pressure of 0.88 mm Hg at 25 °C, EGBE will exist almost entirely in the 

vapor phase in the atmosphere. EGBE may contribute to the formation of tropospheric ozone 

(Derwent, 1996; U.S. EPA, 2006). EGBE is not expected to undergo hydrolysis in the 

environment since this substance lacks hydrolyzable functional groups (HSDB, 2007).
8

1.6.3. Biotic Degradation. 

Limited information is available regarding the aerobic biodegradation of EGBE. 

Screening level data indicate that EGBE is readily biodegradable under aerobic conditions (CITI, 

1992; Devillers et al., 2001; NITE 2002; OECD, 1997; Price et al., 1974; Staples et al., 1998;

Waggy et al., 1994). Price et al. (1974) reported 88% and 75% biodegradation after 20 days in 

non-acclimated fresh water and synthetic salt water, respectively, measured by biochemical 

oxygen demand (BOD). A similar result was reported by Waggy et al. (1994), who measured 

88% biodegradation by Johanson (1988) after 20 days. Waggy et al. (1994) also performed a 

closed-bottle screening test following OECD Guideline 301D and measured 75% biodegradation 

after 28 days. EGBE was biodegraded by 96% after 14 days in a sewage sludge inoculum during 

a Modified MITI screening test (CITI, 1992). Based on the results of the closed bottle and 

Modified MITI screening tests, this substance meets the criteria specified within OECD 

Guidelines for a readily biodegradable substance (Staples et al., 1998). Specific information 

regarding transformation products of EGBE in water and soil was not located in the available 

literature. Results from a pure-culture biodegradation study indicate that ethylene glycol 

monoalkyl ethers like EGBE undergo microbial oxidation at their terminal alcohol groups

(Kawai 1995). In this study, degradation of ethylene glycol monoethyl ether and diethylene 

glycol monoethyl ether by an isolated microbial culture resulted in the formation of ethoxyacetic 

acid and ethoxyglycoxyacetic acid, respectively (Kawai 1995). Following this pathway, the 

microbial degradation of EGBE in the environment is expected to form 2-butoxyacetic acid.

Information regarding the biodegradation of EGBE under anaerobic conditions, such as 

in groundwater, is not currently available.
9

1.6.4. Environmental Distribution Assessment. 

A model (U.S. EPA, 2008) estimate was conducted of how, on a percentage basis, EGBE 

may distribute when it is released into the environment. Measured physical-chemical properties 

(melting point, boiling point, vapor pressure, octanol-water partition coefficient, water solubility, 

and Henry's law constant) were used as model input parameters. Emission inputs (82% to air, 

8% to water, and 7% to soil) were based on the assumption that TRI release data for the “certain 

glycol ethers” category are representative of EGBE releases. Model half-life input values were 

assigned based on the photooxidation half-life for air and biodegradation screening test data for 

water, soil, and sediment3. The advective flow rate was set to zero by selecting very large 

advection times (1×1020 hours) for the air, water, and sediment environmental compartments. 

Based upon the model results, soil is the environmental compartment where the largest mass of 

EGBE will accumulate (47%), with less partitioning to water (33%) and air (20%). The model 

partitioning results, half-life inputs, and emissions inputs for each environmental compartment 

are shown in Table 1-2.

 Table 1-2, Environmental Distribution of EGBE

Compartment Mass amount 

(percent)

Half-life Values 

(hours) 

Emissions

(kg/hr)

Air 47% 9.2 820

Water 33% 120 80

Soil 20% 240 70

Sediment 0% 1080 0

Source: EPI Suite, (U.S. EPA, 2008)

 

3 The half-life value used for water was determined by applying a classification scheme developed by Aronson et al. 

(2006) to the measured screening test data located in the literature for EGBE. Half-lives in soil and sediment were 

set equal to the derived half-life in water multiplied by factors of 2 and 9, respectively, which follows the 

methodology used within the EPI Suite model.
10

1.6.5. Toxic Transformation Products. 

According to Stemmler et al. (1997) and Tuazon et al. (1998), two of the major products 

of EGBE photooxidation are the aldehydes, butoxyacetaldehyde and propionaldehyde; the two 

aldehydes result in a combined quantity approximately equal to 30 to 40 percent of the EGBE 

reacted (Stemmler et al. 1997; Tuazon et al. 1998). As discussed in Section 1.6.2., these 

aldehydes can react with photochemically produced hydroxy radicals in air resulting in the 

formation of acyl peroxy radicals, which can then combine with O2 and NO2 to form the 

peroxyacyl nitrates, peroxybutoxyacetyl nitrate, and peroxylpropionyl nitrate (analogs of PAN) 

(Atkinson, 2000; LOOP, 2003). No information regarding actual yields of peroxyacyl nitrates 

that result from the atmospheric photooxidation of EGBE was located in the literature. 

Peroxyacyl nitrates have a lifetime that is temperature dependent, approximately 30 minutes at 

room temperature (Atkinson, 2000), to over a year at upper troposphere temperatures (Atkinson, 

2000; LOOP, 2003; Roberts, 1990). Peroxyacyl nitrates have been reported to be eye irritants, 

mutagenic, phytotoxic, and possible agents of skin cancer (Singh and Salas, 1989; Williams et al. 

1993). PAN has been shown to be mutagenic in Salmonella and in the lungs of mice exposed 

nose-only to PAN generated from non-mutagenic precursors (DeMarini et al., 2000).

With respect to the formation of toxic biodegradation products in soil and water, no 

EGBE specific literature was available. Results from a pure-culture biodegradation study 

indicate that ethylene glycol monoalkyl ethers like EGBE undergo microbial oxidation at their 

terminal alcohol groups (Kawai 1995). In this study, degradation of ethylene glycol monoethyl 

ether and diethylene glycol monoethyl ether by an isolated microbial culture resulted in the 

formation of ethoxyacetic acid and ethoxyglycoxyacetic acid, respectively (Kawai 1995). 

Following this pathway, the microbial degradation of EGBE in the environment is expected to 
11

form 2-butoxyacetic acid. In mammals, 2-butoxyacetic acid is a principal EGBE metabolite, 

which is thought to be responsible for EGBE’s toxic hematological effects (U.S. EPA, 1999).

1.7. REFERENCES

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with organic compounds. J. Phys. Chem. Ref. Data Monograph. 1:141.

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Walsh, D., de Boer, J.G., Lewis-Bevan, L., Rabinowitz, J.R., Claxton, L.D., Lewtas, J. 2000. 

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by the air pollutant peroxyacetyl nitrate (PAN): predicted formation of intrastrand cross-links. 

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Derwent, R.G., M.E. Jenkin, S.M. Saunders, et al. 1996. Photochemical Ozone Creation 

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Dow, 1990. The Glycol Ethers Handbook. The Dow Chemical Company. Midland, MI. pp. 97.

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Hansch, C., A. Leo and D. Hoeckman. 1995. Exploring QSAR: Hydrophobic, electronic, and 

steric constants. p. 25. 

HSDB. 2007. Ethylene glycol mono-N-butyl ether. Hazardous Substances Data Bank. 

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Their Implications on Volatile Organic Compound Emissions from Automotive Painting. Water 

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York, NY. p. 466.

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& Francis Group, Boca Raton. p. 3-76.

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Final). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/004aF-cF. 

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PPN, and and MPAN in Atlanta, Georgia. J. Air Waste Manage. Assoc. 43: 873-879.
15

CHAPTER TWO

ECOLOGICAL HAZARD ASSESSMENT

2.1 SUMMARY 

Based upon available acute toxicity data, EGBE does not appear to present a significant 

concern for adverse effects on the aquatic environment since effects occur at relatively high 

concentrations indicating low toxicity. Such high concentrations are not expected to be observed 

under typical environmental conditions. Experimental acute toxicity LC50 ((i.e., the 

concentration that is lethal to 50% of test organisms) or EC50 ((i.e., the concentration that is 

effective in producing a sublethal response in 50% of test organisms) values range from 900 to 

1,840 mg/L for green algae, 164 to 1,815 mg/L for freshwater invertebrates, and 1,395 to 2,137 

mg/L for freshwater fish. Available experimental acute toxicity LC50 values for saltwater 

invertebrates and saltwater fish were 1,000 and 1,250 mg/L, respectively; a 24-hour lowestobserved-effect concentration (LOEC) (embryotoxicity) of 1,000 mg/L was available for 

Japanese oyster eggs. These acute experimental toxicity values indicate low aquatic toxicity. 

Experimental chronic toxicity values range from 35 to >1,000 mg/L for algae and from 100 to 

297 mg/L for daphnids. Also, a 21-day no-observed-effect-concentration (NOEC) of >100 mg/L 

was available for freshwater fish. These chronic experimental toxicity values indicate low to 

moderate aquatic toxicity (Table 2-1). For terrestrial toxicity, an ECOSAR-predicted 14-day 

LC50 of 1,666 mg/kg dry weight soil for earthworms was available. EGBE is not expected to 

bioaccumulate significantly in aquatic organisms (the BCF is 3 based on a log Kow of 0.83). 

2.2. ECOLOGICAL TOXICITY

Databases searched to identify studies on ecological toxicity were ECOTOX (2007) 

(which contains three databases: AQUIRE, PHYTOTOX, and TERRETOX), the Office of 

Pesticide Programs (OPP) Environmental Fate and Effects Division (EFED) Pesticide 
16

Ecotoxicity Database, and the Hazardous Substances Databank (HSDB). In addition, the 

TOXLINE database was searched to identify additional aquatic toxicity studies and population 

effects studies. No experimental chronic toxicity data for fish or aquatic invertebrates were 

found for EGBE. Limited experimental toxicity data were available for all other endpoints. 

Quantitative Structure-Activity Relationships (QSARs) were considered for some ecological 

toxicity endpoints for EGBE; however, QSAR models were not available to predict the chronic 

toxicity of EGBE to estuarine/marine fish or invertebrates.

EPA’s Ecological Structure Activity Relationship Program (ECOSAR) (U.S. EPA, 2008)

was used to supplement available experimental data. ECOSAR is a regression-based model 

developed by the EPA Office of Pollution Prevention and Toxics and was used to predict the 

acute and chronic toxicity of EGBE based on structural similarities to chemicals for which 

aquatic toxicity has been measured experimentally. ECOSAR-derived acute aquatic toxicity 

values were generated for estuarine/marine fish and invertebrates (mysid shrimp), and ECOSARderived chronic aquatic toxicity values were generated for green algae and freshwater fish. The 

predicted 96-hour LC50 values for estuarine/marine fish and invertebrates were 1,481 and 2,240 

mg/L, respectively. The predicted chronic toxicity values for green algae and freshwater fish 

were 42 and 94 mg/L, respectively. Table 2-1 presents the measured and predicted values 

indicating acute and chronic toxicity of EGBE to aquatic organisms and toxicity to terrestrial 

organisms. 
17

 

 Table 2-1. Ecological Toxicity Values for EGBE

Species Duration and Test 

Endpoint

Experimental 

Typea,b

Value 

(mg/L)c Reference

Acute aquatic toxicity

Algae

Green algae (Scenedesmus 

quadricauda)

Toxicity threshold

value S, Uh 900 Bringmann & Kuhn, 1977af

Green algae 

(Pseudokirchneriella 

subcapitata)

72-hr EC50 (biomass) S, Me,i 911 Devillers et al., 2002a, 

2002b

Green algae 

(Pseudokirchneriella 

subcapitata)

72-hr EC50 (growth) S, Me,i 1,840 Devillers et al., 2002a, 

2002b

Green algae 

(Pseudokirchneriella 

subcapitata)

72-hr NOEC (growth 

rate) S, M 286 INERIS, 1999d, as cited in ECB, 2006

Green algae 

(Pseudokirchneriella 

subcapitata)

72-hr NOEC 

(biomass) S, M 88 INERIS, 1999d, as cited in ECB, 2006

Freshwater invertebrate

Water flea (Daphnia magna) 24-hr EC50 S, U, Og 1,720 Bringmann & Kuhn, 

1977bf

Water flea (Daphnia magna) 48-hr EC50 S, U, Oe 1,815 Bringmann & Kuhn, 1982

Water flea (Daphnia magna) 48-hr EC50 S, Ok 835

Dow Chemical Company, 

1979, as cited in ECB, 

2006

Water flea (Daphnia magna) 48-hr EC50 S

m 1,550 INERIS, 1999a, as cited in 

ECB, 2006

Water flea (Daphnia magna) 48-hr EC50 S, Mo 1,600 Devillers et al., 2002a, 

2002b

Rotifer (Brachionus 

calyciflorus)

48-hr EC50

(reproduction) S, Mp 164 Devillers et al., 2002a, 2002b

Freshwater fish

Bluegill (Lepomis 

macrochirus)

96-hr LC50 S, U 1,490 Dawson et al., 1975

Golden orfe (Leuciscus idus) LC50

d NSe 1,575 Juhnke & Luedemann, 

1978f

Golden orfe (Leuciscus idus) LC50

d NSe 1,395 Juhnke & Luedemann, 

1978f

Goldfish (Carassius auratus) 24-hr LC50 S, Me 1,700 Bridie et al., 1979

Rainbow trout 

(Oncorhynchus mykiss)

96-hr LC50 Mk,q 1,700 Devillers et al., 2002a, 

2002b

Rainbow trout 

(Oncorhynchus mykiss)

96-hr LC50 NSk,m 1,474 INERIS, 1999b, as cited 

in ECB, 2006
18

Species Duration and Test 

Endpoint

Experimental 

Typea,b

Value 

(mg/L)c Reference

Fathead minnow 

(Pimephales promelas)

96-hr LC50 S, Ok 2,137

Dow Chemical Company, 

1979, as cited in ECB, 

2006

Estuarine/marine invertebrate

Brine shrimp (Artemia 

salina)

24-hr LC50 S, U, C 1,000 Price et al., 1974

Japanese oyster eggs 

(Crassostrea gigas)

24-hr LOEC 

(embryotoxicity) S

k 1,000 Devillers et al., 2002a, 

2002b

Mysid shrimp predicted 

value 96-hr LC50 predicted 2,240 ECOSAR v. 1.00, U.S. EPA, 2008

Estuarine/marine fish

Silverside (Menidia 

beryllina)

96-hr LC50 S, U 1,250 Dawson et al., 1975

Saltwater fish predicted 

value 96-hr LC50 predicted 1,481 ECOSAR v. 1.00, U.S. EPA, 2008

Chronic aquatic toxicity

Algae

Green algae (Scenedesmus 

quadricauda)

8-d LOEC (cell 

multiplication 

inhibition)

S, Ue 900 Bringmann & Kuhn, 

1978afand 1978b

Blue-green algae 

(Microcystis aeruginosa)

8-d LOEC (cell 

multiplication 

inhibition)

S, Ue 35 Bringmann & Kuhn, 

1978afand 1978b

Green algae (Selenastrum 

capricornutum)

7-d EC50 (growth rate) S, Ue >1,000 Dill & Milazzo, 1988

Green algae predicted value Chronic Value predicted 42 ECOSAR v. 1.00, U.S. 

EPA, 2008

Freshwater invertebrate

Water flea (Ceriodaphnia 

dubia)

7-day EC10

(reproduction) R, N 134.9 Devillers et al., 2003

Water flea (Daphnia magna)

21-d NOEC 

(reproduction) R, M 100 Devillers et al., 2002a, 2002b

Water flea (Daphnia magna) 21-d NOECn R, M 100 INERIS, 1999c, as cited in 

ECB, 2006

Water flea (Daphnia magna) 21-d EC50

n R, M 297 INERIS, 1999c, as cited in 

ECB, 2006

Freshwater fish

Zebrafish (Brachydanio 

rerio)

21-d NOEC 

(mortality) NSl >100 INERIS, 2001, as cited in ECB, 2006

Freshwater fish predicted 

value 30-d Chronic Value predicted 94 ECOSAR v. 1.00, U.S. EPA, 2008

Estuarine/marine invertebrate - No data

Estuarine/marine fish - No data

Terrestrial toxicity and phytotoxicity

Avian species - No data
19

Species Duration and Test 

Endpoint

Experimental 

Typea,b

Value 

(mg/L)c Reference

Terrestrial invertebrate

Earthworm predicted value 14-d LC50 predicted

272 mg/kg 

dry weight 

soil

ECOSAR v. 1.00, U.S. 

EPA, 2008

Plants - No data

aFor freshwater tests, pH and water hardness were within accepted ranges (6-8.5 and 50-250 mg/L as CaCO3, 

respectively) unless noted otherwise

bExperiment type: S = static, R = renewal, M = measured, U = unmeasured, O = open test system, NS = not 

specified

cmg/L = ppm 

dTest duration was not noted in the study report.

eWater hardness was not reported.

fMost of the study report was in German and a full English translation was not available.

gWater hardness was reported as 16° dH, equivalent to 285.76 mg/L as CaCO3.

h

It was unclear from the study report whether test concentrations were measured. ECOTOX reported that the 

test was static and that test concentrations were nominal.

ipH was not reported.

jWater hardness was reported as 25 mg/L as CaCO3.

k

It was not indicated whether test concentrations were nominal or measured.

lWater hardness, pH, test type, and whether test concentrations were nominal or measured were not 

indicated.

mTest type was unclear from the report.

nThe effect on which the endpoint value was based (e.g., reproduction? mortality?) was not indicated in the 

report.

oWater hardness was reported as 250±20 mg/L as CaCO3.

pWater hardness was described as “moderately hard.”

qWater hardness was reported as 250±25 mg/L as CaCO3.

2.2.1. Acute Toxicity. 

Acute toxicity values are presented in Table 2-1. For green algae, a toxicity threshold 

value (duration not specified) of 900 mg/L and 72-hour EC50 values of 911 and 1,840 mg/L for 

biomass and growth rate, respectively, were reported (corresponding 72-hr NOEC values for 

biomass and growth rate were 88 and 286 mg/L). For daphnids, 24- or 48-hour EC50 values 

ranged from 835 to 1,815 mg/L, and a 48-hr EC50 (reproduction) of 164 mg/L in rotifers was 

reported. A 96-hour LC50 value of 1,490 mg/L was available for bluegill sunfish and 96-hour 

LC50 values for rainbow trout were 1,474 and 1,700 mg/L. A 96-hour LC50 value of 2,137 mg/L 

for fathead minnows was also reported. LC50 values (duration not specified) of 1,575 and 1,395 

mg/L were available for golden orfe (Leuciscus idus), and a 24-hour LC50 value of 1,700 mg/L 

was available for goldfish (Carassius auratus). A study of a lacustrine invertebrate (brine 
20

shrimp) reported a 24-hour LC50 value of 1,000 mg/L, but the brine shrimp is not a standard test 

species and the test duration was only 24 hours. Also, an embryo-larval test in which Japanese 

oyster eggs were incubated with the test material for 24 hours and then examined for 

abnormalities produced a 24-hr LOEC of 1,000 mg/L. ECOSAR predicted a 96-hour LC50 value 

of 2,240 mg/L for mysid shrimp. A study of an estuarine/marine fish (silverside, Menidia 

beryllina) reported a 96-hour LC50 value of 1,250 mg/L. Additionally, ECOSAR predicted a 96-

hour LC50 value of 1,481 mg/L for estuarine/marine fish. 

2.2.2. Chronic Toxicity. 

Chronic toxicity values are presented in Table 2-1. Eight-day LOEC values (cell 

multiplication inhibition) of 900 and 35 mg/L were available for green algae and blue-green 

algae, respectively, and a 7-day EC50 value of >1,000 mg/L was available for green algae. 

ECOSAR predicted a chronic value of 42 mg/L for green algae (ECOSAR chronic values are 

indicative of lowest adverse effect levels associated with the ability to survive, grow, and/or 

reproduce). For daphnids, the following endpoint values were available: a 7-day EC10

(reproduction) of 134 mg/L, a 21-day NOEC (reproduction) of 100 mg/L, and a 21-day EC50

(effect not specified) of 297 mg/L. For freshwater fish, a 21-day NOEC (mortality) of >100 

mg/L was available, and ECOSAR predicted a 30-day chronic value of 94 mg/L. There were no 

measured or predicted chronic estuarine/marine fish or invertebrate toxicity data available.

2.2.3. Terrestrial Toxicity and Phytotoxicity. 

Ecological toxicity values are presented in Table 2-1; no avian toxicity or phytotoxicity 

data were available. ECOSAR predicted a 14-day LC50 of 272 mg/kg dry weight soil for 

earthworms.
21

2.2.4. Population Effects. 

No data on population effects were located.

2.2.5. Bioaccumulation Potential. 

Bioaccumulation in aquatic organisms can be estimated using the BCF, which describes 

the degree to which a chemical can be concentrated in the tissues of an organism. Measured 

BCFs were not available; thus, a BCF was calculated using EPIWIN v. 3.2 (U.S. EPA, 2008). 

Based on a calculated BCF of 3, EGBE is not expected to bioaccumulate significantly in the 

tissues of aquatic organisms.

2.3. REFERENCES

Bridie, A.L., Wolff, C.J.M., & M. Winter. 1979. The acute toxicity of some petrochemicals to 

goldfish. Water Res, 13(7): 623-626.

Bringmann, G. & R. Kuhn. 1977a. Limiting values for the damaging action of water pollutants 

to bacteria (Pseudomonas putida) and green algae (Scenedesmus quadricauda) in the cell 

multiplication inhibition test.. Z. Wasser Abwasser Forsch, 10(3/4): 87-98. (In German)

Bringmann, G. & R. Kuhn. 1977b. The effects of water pollutants on Daphnia magna. Z. 

Wasser Abwasser Forsch, 10(5): 161-166. (In German)

Bringmann, G. & R. Kuhn. 1978a. Threshold Values of Substances Harmful to Water for Blue 

Algae (Microcystis aeruginosa) and Green Algae (Scenedesmus quadricauda) in Tests 

Measuring the Inhibition of Cellular Propagation. Vom Wasser 50:45-60 (GER) (ENG ABS), 

Tr-80-0201, Literature Research Company: 22 p.

Bringmann, G. & R. Kuhn. 1978b. Testing of Substances for Their Toxicity Threshold: Model 

Organisms Microcystis (Diplocystis) aeruginosa and Scenedesmus quadricauda. Mitt. Int. Ver. 

Theor. Angew. Limnol. 21: 275-284.

 

Bringmann, G. & R. Kuhn. 1982. Results of the toxic action of water pollutants on Daphnia 

magna in an improved standardized procedure. Z. Wasser Abwasser Forsch, 15(1): 1-6. (In 

German)

Dawson, G.W., Jennings, A.L., Drozdowski, D., & E. Rider. 1975. The acute toxicity of 47 

industrial chemicals to fresh and saltwater fishes. Journal of Hazardous Materials, 1: 303-318.
22

Devillers, J., Chezeau, A., Poulsen, V. & E. Thybaud. 2003. Effects of ethylene glycol ethers on 

the reproduction of Ceriodaphnia dubia. Chemosphere, 50: 373-376.

Devillers, J., Chezeau, A., Thybaud, E., Poulsen, V., Procher, J.-M., Graff, L., Vasseur, P., 

Mouchet, F., Ferrier, V. & F. Quiniou. 2002a. Ecotoxicity of ethylene glycol monobutyl ether 

and its acetate. Toxicology Mechanisms and Methods, 12: 255-263.

Devillers, J., Chezeau, A., Thybaud, E., Poulsen, J.-M., Graff, L., Vasseur, P., Chenon, P., 

Mouchet, F., Ferrier, V. & F. Quiniou. 2002b. Ecotoxicity of ethylene glycol monomethyl ether 

and its acetate. Toxicology Mechanisms and Methods, 12: 241-254.

Dill, D.C. & D.P. Milazzo. 1988. Dowanol PM Glycol Ether: Evaluation of the toxicity to the 

green alga, Selenastrum capricornutum printz. July 18, 1988. Dow Chemical Company. EPA 

Document Control Number 86-890001160. 18 pages.

Dow Chemical Co. 1979. Toxicity of Dowanol EB to freshwater organisms (redactor: Bartlett), 

31 August 1979. As cited in ECB, 2006.

ECB (European Chemicals Bureau). 2006. European Union Risk Assessment Report for 2-

Butoxyethanol (EGBE). Vol. 68. European Commission.

ECOSAR (v. 1.00h, part of the EPIWIN Suite v.3.2, see U.S. EPA 2008). 2008. Syracuse 

Research Corporation. Available at http://www.epa.gov/opptintr/newchems/tools/21ecosar.htm.

ECOTOX. 2007. ECOTOX User Guide: ECOTOXicology Database System. Version 4.0, 

Released February 2007. Available at http://www.epa.gov/ecotox/.

HSDB (Hazardous Substances Databank). National Library of Medicine. Available at: 

http://toxnet.nlm.nih.gov.

Toxicology Data Network (TOXNET7 ). Bethesda, MD. Available at 

http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB.

INERIS. 2001. Essai poisson 21 jours, Danio rerio, unpublished report, N° 22685, 05.11.2001. 

As cited in ECB, 2006.

INERIS. 1999a. Détermination de la toxicité aïgue du 2-butoxyethanol vis-à-vis de Daphnia 

Magna, Ba746b-CGR21427. Verneuil-en-Halatte, France, 14 décembre 1999, INERIS: 10. As 

cited in ECB, 2006.

INERIS. 1999b. Détermination de la toxicité aiguë du 2-butoxyethanol vis-à-vis de 

Oncorhynchus Mykiss, unpublished, Ba746f-CGR21427. Verneuil-en-Halatte, France, 14 

décembre 1999, INERIS: 10. As cited in ECB, 2006.

INERIS (1999c) Détermination de la toxicité chronique du 2-butoxyethanol vis-à-vis de Daphnia 

Magna, Ba746a-CGR21427. Verneuil-en-Halatte, France, 15 décembre 1999, INERIS: 13. As 

cited in ECB, 2006.
23

INERIS (1999d) Détermination de la toxicité chronique du 2-butoxyethanol vis-à-vis de l'algue 

d'eau douce Pseudokirchneriella Subcapitata, Ba746d-CGR21427. Verneuil-en-Halatte, France, 

14 décembre 1999, INERIS: 14. As cited in ECB, 2006.

Juhnke, I. & D. Luedemann. 1978. Results of the study of 200 chemical compounds on acute 

fish toxicity using the Golden Orfe test. Z. Wasser Abwasser Forsch., 11(5): 161-164. (In 

German)

Price, K.S., Waggy, G.T., & R.A. Conway. 1974. Brine shrimp bioassay and seawater BOD of 

petrochemicals. Journal WPCF, 46(1): 63-76.

TOXLINE. Part of the National Library of Medicine's Toxicology Data Network (TOXNET7 ). 

Bethesda, MD. Available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?TOXLINE.

U.S. EPA. 2008. ECOSAR v.1.00. Available within the EPI SuiteTM v.4.00. program ©2008 

U.S. Environmental Protection Agency. Available as part of the EPI Suite program v 4.00 at 

http://www.epa.gov/oppt/exposure/pubs/episuite.htm.