x-xEPA
United States
Environmental Protection
Agency
Office of Water
Regulations and Standards (WH-553)
Washington DC 20460
July 1983
EPA-440/4-85-016
Water
An Exposure
and Risk Assessment
for Toluene
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DISCLAIMER
This is a contractor's final report, which has been reviewed by the Monitoring and Data Support
Division, U.S. EPA. The contents do not necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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30779-101
REPORT DOCUMENTATION i. REPORT NO. oen,f «•
PAGE EPA-440/4-85-016
«. Title ind Subtitle
An Exposure and Risk Assessment for Toluene
7. Author^ Gilbert, D. ; Woodruff, C.; Preston, A.; Thomas, R, ; et al
(ADL) Moss, K.; DeRosier, R. ; Cruse, P. (Acurex Corporation)
9. Performing Organization Nam* and Address
Arthur D. Little, Inc. Acurex Corporation
20 Acorn Park 485 Clyde Avenue
Cambridge, MA 02140 Mt. View, CA 94042
1
12. Sponsoring Organization Nam* and Address
1 Monitoring and Data Support Division
Office of Water Regulations and Standards
U.S. Environmental Protection Agency
. Washington, D.C. 20460
3. Recipient's Accaulon No.
5. Report DM* Final Revision
July 1983
ft.
8. Parformmg Organization Root. No.
10. Proiect/Taek/Work Unit No.
11. Contracted or Grant(G) No.
(0 C-68-01-6160
C-68-01-6167
(6)
13. Typo of Raport A Ponod Coworod
Final
14.
I 15. Supplementary Notes
Extensive Bibliographies
IS. Abstract (Umlt 200 «rards)
i This report assesses the risk of exposure to toluene. This study is part of a program
• to identify the sources of and evaluate exposure to 129 priority pollutants. The
analysis is based on available information from government, industry, and technical
publications assembled in June of 1981.
The assessment includes an identification of releases to the environment during
production, use, or disposal of the substance. In addition, the fate of toluene in
I the environment is considered; ambient levels to which various populations of humans
and aquatic life are exposed are reported. Exposure levels are estimated and
available data on toxicity are presented and interpreted. Information concerning all
i of these topics is combined in an assessment of the risks of exposure to toluene for
' various subpopulations.
I
17. Document Anolyde a. Descriptors
Exposure
i Risk
' Water Pollution
Air Pollution
i b. tdenttflers/Open-Ended Tormt
Pollutant Pathways
. Risk Assessment
c. COSATI Field/Croup
Effluents
Waste Disposal
Food Contamination
Toxic Diseases
Toluene
• IS. Availability Statement
' Release to Public
19. Security CUM (Thl* Report)
Unclassified
20. Security Clan (Thli Page)
Unclassified
21. No. of Page*
155
22. Price
516.00
(SeoANSI-a9.18>
See Inatructlona on Revert*
OPTIONAL FORM 272 («-77>
(Formerly NT1S-3S)
Department of Commerce)
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EPA-440/4-85-016
June 1981
(Revised July 1983)
AN EXPOSURE AND RISK ASSESSMENT
FOR TOLUENE
Diane Gilbert
Caren Woodruff, Alan Preston, Richard Thomas,
Melba Wood, William Steber, Melanie Byrne
Arthur D. Little, Inc.
U.S. EPA Contract 68-01-6160
Kenneth Moss, Robert DeRosier, Patricia Cruse
Acurex Corporation
U.S. EPA Contract 68-01-6167
Ann Thomas Carkhuff
Project Manager
U.S. Environmental Protection Agency
Monitoring and Data Support Division (WH-553)
Office of Water Regulations and Standards
Washington, D.C. 20460
OFFICE OF WATER REGULATIONS AND STANDARDS
OFFICE OF WATER AND WASTE MANAGEMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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FOREWORD
Effective regulatory action for toxic chemicals requires an
understanding of the human and environmental risks associated with the
manufacture, use, and disposal of the chemical. Assessment of risk
requires a scientific judgment about the probability cf harm to the
environment resulting from known or potential environmental concentra-
tions. The risk assessment process integrates health effects data
(e.g., carcinogeniclty, teratogenicity) with information on exposure.
The components of exposure include an evaluation of the sources of the
chemical, exposure pathways, ambient levels, and an identification of
exposed populations including humans and aquatic life.
This assessment was performed as part of a program to determine
the environmental risks associated with current use and disposal
patterns for 65 chemicals and classes of chemicals (expanded to 129
"priority pollutants") named in the 1977 Clean Water Act. It includes
an assessment of risk for humans and aquatic life and is intended to
serve as a technical basis for developing the most appropriate and
effective strategy for mitigating these risks.
This document is a contractors' final report. Tt has been
extensively reviewed by the Individual contractors £>nd by the EPA at
several stages of completion. Each chapter of the draft was reviewed
by members of the authoring contractor's senior technical staff (e.g.,
toxicologists, environmental scientists) who had not previously been
directly involved in the work. These individuals were selected by
management to be the technical peers of the chapter authors. The
chapters were comprehensively checked for uniformity in quality and
content by the contractor's editorial team, which also was responsible
for the production of the final report. The contractor's senior
project management subsequently reviewed the final report in its
entirety.
At EPA a senior staff member was responsible for guiding the
contractors, reviewing the manuscripts, and soliciting comments, where
appropriate, from related programs within EPA (e.g., Office of Toxic
Substances, Research and Development, Air Programs, Solid and
Hazardous Waste, etc.). A complete draft was summarized by the
assigned EPA staff member and reviewed for technical and policy
implications with the Office Director (formerly the Deputy Assistant
Administrator) of Water Regulations and Standards. Subsequent revi-
sions were included in the final report.
Michael W. Slimak, Chief
Exposure Assessment Section
Monitoring & Data Support Division (WH-553)
Office of Water Regulations and Standards
iii
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TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES x
1.0 TECHNICAL SUMMARY 1-1
1.1 Materials Balance 1-1
1.2 Environmental Fate 1-1
1.3 Human Health Effects and Exposure 1-2
1.4 Aquatic Effects and Exposure 1-3
1.5 Risk Considerations 1-4
2.0 INTRODUCTION 2-1
References 2-3
3.0 MATERIALS BALANCE 3-1
3.1 Introduction 3-1
3.2 Production of Toluene 3-1
3.2.1 Production of Isolated Toluene 3-3
3.2.1.1 Catalytic Reformate 3-5
3.2.1.2 Pyrolysis Gasoline 3-5
3.2.1.3 Styrene Manufacture 3-5
3.2.1.4 Coal Sources 3-6
3.2.1.5 Exports and Imports 3-6
3.2.2 Nonisolated Toluene 3-6
3.2.2.1 Catalytic Reformate and Pyrolysis Gasoline 3-6
3.2.2.2 Coke Ovens 3-6
3.2.3 Environmental Releases 3-7
3.2.4 Inadvertent Sources 3-7
3.3 Uses of Toluene 3-7
3.3.1 Gasoline 3-9 v
3.3.2 Chemical Synthesis 3-9
3.3.2.1 Benzene 3-9
3.3.2.2 Manufacture of Toluene Diisocyanate 3-9
3.3.2.3 Other Chemical Intermediate Uses 3-12
3.3.3 Solvent Uses 3-12
3.3.4 Environmental Releases 3-15
3.4 Municipal Disposal of Toluene 3-15
3.4.1 POTWs 3-18
3.4.2 Urban Refuse 3-18
References 3-22
4.0 FATE AND DISTRIBUTION OF TOLUENE IN THE ENVIRONMENT 4-1
4.1 Introduction 4-1
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TABLE OF CONTENTS (Continued)
4.2 Physical, Chemical, and Biological Characteristics
of Toluene 4-1
4.3 Levels Monitored in the Environment 4-3
4.3.1 Water Concentrations 4-3
4.3.1.1 Drinking and Well Waters 4-3
4.3.1.2 Ambient and Effluent Waters 4-8
4.3.1.3 Rainwater and Other Precipitation 4-14
4.3.2 Concentrations in Sediment 4-14
4.3.3 Concentrations in Foods 4-14
4.3.3.1 Fish Tissue 4-14
4.3.3.2 Other Foods 4-14
4.3.4 Concentrations in the Atmosphere 4-16
4.3.4.1 Contributions from Stationary and
Mobile Sources 4-16
4.3.4.2 Contributions by Vegetation 4-19
4.3.4.3 Contributions from Cigarettes 4-20
4.4 Environmental Fate Modeling and Analysis 4-20
4.4.1 EXAMS Modeling 4-20
4.4.2 Intermedia Transfers 4-23
4.4.2.1 From Air Medium to Surface Waters or Land &-23
4.4.2.2 Water 4-23
4.4.2.3 Soil 4-23
4.4.3 Intramedia Fate Processes 4-24
4.4.3.1 Air 4-24
4.4.3.2 Water 4-29
4.4.3.3 Soil 4-31
4.4.3.4 Biota 4-32
4.5 Summary 4-35
4.5.1 Intermedium Transfer Processes 4-35
4.5.1.1 Air 4-35
4.5.1.2 Water 4-35
4.5.1.3 Soil 4-37
4.5.2 Intramedium Fate Processes 4-37
4.5.2.1 Air 4-37
4.5.2.2 Water 4-37
4.2.5.3 Soil 4-37
4.5.3 Critical Pathways for Specific Sources of Toluene 4-38
References 4-40
5.0 HUMAN EFFECTS AND EXPOSURE 5-1
5.1 Human Effects 5-1
5.1.1 Pharmacokinetics 5-1
5.1.1.1 Absorption 5-1
5.1.1.2 Distribution 5-3
5.1.1.3 Metabolism and Elimination 5-7
vi
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TABLE OF CONTENTS (Continued)
5.1.2 Acute Effects 5-10
5.1.3 Chronic Effects 5-11
5.1.3.1 Myelotoxicity 5-11
5.1.3.2 Central Nervous System Toxicity 5-18
5.1.3.3 Other Chronic Toxic Effects 5-20
5.1.3.4 Carcinogenicity 5-20
5.1.3.5 Reproductive Toxicity 5-20
5.1.4 Additional Health Effects 5-21
5.1.5 Estimation of Human Risk 5-24
5.2 Human Exposure 5-25
5.2.1 Introduction 5-25
5.2.2 Exposure through Drinking Water and Food 5-25
5.2.3 Exposure through Inhalation 5-26
5.2.4 Percutaneous Exposure 5-29
5.2.4.1 Occupational Exposure 5-29
5.2.4.2 Consumer Products 5-30
5.2.5 Total Exposure Scenarios and Conclusions 5-30
5.2.6 Summary 5-31
References 5-33
6.0 BIOTIC EFFECTS AND EXPOSURE 6-1
6.1 Siotic Effects 6-1
6.1.1 Introduction 6-1
6.1.2 Mechanisms of Toxicity 6-1
6.1.3 Freshwater Organisms 6-2
6.1.4 Marine Organisms 6-2
6.1.5 Phytotoxicity 6-5
6.1.6 Factors Affecting the Toxicity of Toluene 6-5
6.1.7 Summary 6-5
6.2 Exposure of Aquatic Biota to Toluene 6-11
6.2.1 Introduction 6-11
6.2.2 Exposure Routes 6-11
6.2.3 Monitoring Data 6-11
6.2.4 Modeling Data 6-12
6.2.5 Conclusions 6-12
References 6-14
7.0 RISK CONSIDERATIONS 7-1
7.1 Human Risks 7-1
7.2 Aquatic Organism Risks 7-2
References 7-4
vii
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TABLE OF CONTENTS (Continued)
Page
APPENDIX A A-l
APPENDIX B 3-1
APPENDIX C C-l
APPENDIX D D-l
APPENDIX E E-l
APPENDIX F F-l
viii
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LIST OF FIGURES
Figure
No. Page
3-1 Toluene Materials Balance (103 kkg) 3-2
4-1 Reaction of Hydroxyl Radicals with Toluene 4-27
4-2 Tissue Concentration Factors (TCF) for Toluene
in Various Bluegill Sunfish Organs at Given
Times of Exposure 4-33
4-3 Tissue Concentration Factors (TCF) for Toluene in
Various Crayfish Organs at Given Times of Exposure 4-34
4-4 Major Fate Processes for Toluene 4-36
4-5 Critical Pathways for Toluene 4-39
5-1 Metabolism of Toluene in Humans 5-8
F-l Vertical Dispersion Coefficient as a Function
of Downwind Distance from the Source F-2
F-2 Horizontal Dispersion Coefficient as a Function
of Downwind Distance from the Source F-3
ix
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LIST OF TABLES
Table
No. Page
3-1 Toluene Production, 1973 (kkg/yr) 3-4
3-2 Inadvertent Sources of Toluene Releases to
the Environment, 1978 3-8
3-3 Toluene Materials Balance: Uses, 1978 (kkg/yr) 3-10
3-4 Toluene Consumption and Environmental Releases:
Benzene Production, 1978 (kkg/yr) 3-11
3-5 Toluene Releases from Toluene Diisocyanate
Producers, 1978 (kkg/yr) 3-13
3-5 Toluene Consumption and Environmental Releases from
Other Toluene Chemical Intermediate Users, 1978 (kkg) 3-14
3-7 Wastewatar Loading of Toluene: Various Industries 3-16
3-8 Toluene Emissions from Gasoline Marketing 3-17
3-9 Toluene Distribution in POTWs and Sludge, Selected
Urban Sites 3-19
3-10 Toluene Materials Balance: Municipal POTWs and
Refuse (kkg/yr) 3-20
4-1 Physical-Chemical Properties of Toluene Related
to Environmental Distribution 4-2
4-2 Toluene Concentrations in Surface Supplies of
Drinking Water 4-4
4-3 Toluene Concentrations in Groundwater Supplies
of Drinking Water 4-7
4-4 Percentage Distribution of Ambient and Effluent
Toluene Concentrations for Major River Basins and
the United States 4-9
4-5 Ranges of Unremarked Values of Ambient Toluene Concen-
trations from Monitoring Data in Seventeen States 4-10
4-6 Ranges of Unremarked Values of Effluent Toluene Con-
centrations from Monitoring Data in Seventeen States 4-12
4-7 Concentrations of Toluene in Industrial Effluents 4-13
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LIST OF TABLES (Continued)
Table
No. Page
4-7 Concentrations of Toluene in Industrial Effluents 4-13
4-8 Concentrations of Toluene in Wastewaters and
Sludges from POTWs 4-15
4-9 Toluene Concentrations in the Atmosphere of Urban,
Rural and Remote Areas 4-17
4-10 Results of EXAMS Modeling of the Environmental Fate
of Toluene Discharge Scenarios 4-22
4-11 Rate of Atmospheric Oxidation of Toluene BP Free
Radicals 4-28
4-12 Toluene Concentrations in Air Downwind Distances
of Chemical Plants Using Toluene 4-30
5-1 Estimates of the Saturation Half-Life of Toluene
Between Blood and Tissue 5-4
5-2 Toluene Concentrations in Air and Blood 5-6
5-3 Analysis of Paint Used by Painters 5-13
5-4 Frequency of Chromosome Aberrations in Peripheral
Lymphocytes 5-15
5-5 Animal Studies of Myelotoxicity of Toluene
(Negative Studies) 5-16
5-6 Animal Studies of Myelotoxicity (Positive Studies) 5-17
5-7 Layout of the Experiment and Summarized Data of the
Experimental Groups of Benzene, Toluene and Xylene
Treated Pregnant Animals 5-22
5-8 Data of the Fetuses of Benzene, Toluene and Xylene
Treated Pregnant Animals 5-23
5-9 Estimated Human Exposure to Toluene by All Routes 5-28
5-10 Total Human Exposure Scenarios for Toluene 5-32
6-1 Acute Toxicity of Toluene to Freshwater Fish 6-3
6-2 Acute Toxicity of Toluene to Marine Fish 6-4
xi
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LIST OF TABLES (Continued)
Table
N?o. Page
6-3 Chronic Toxicity of Toluene to Marine Fish 6-4
6-4 Acute Toxicity of Toluene to Marine Invertebrates
(Static Tests) 6-6
6-5 Effects of Toluene on Freshwater Plants 6-7
6-6 Effects of Toluene on Marine Plants 6-3
6-7 Interaction of Temperature and Toluene on
Marine Invertebrate 6-9
7-1 Estimated Margins of Safety for Exposure to Toluene 7-3
A-l Emission Factors A-7
A-2 Air Emissions, Calculations from Toluene Production A-8
A-3 Average Effluents from Coke Oven Operations A-8
A-4 Toluene Materials Balance: Production Isolated
from Petroleum Refining, 1978 (kkg/yr) A-9
A-5 Toluene Yields from Various Pyrolysis Feeds A-ll
A-6 Toluene Materials Balance: Production from Styrene
Manufacture, 1978 (kkg) A-12
A-7 Coke Oven Plants which Recover Crude Light Oils A-13
B-l General Formulations Containing Toluene B-l
B-2 Ethylene - Propylene Rubber Extender Oils which
May Contain Toluene B-2
C-l Frequency of Toluene Detection in Industrial
Wastewaters C-l
C-2 Industrial Liquid Streams in which Toluene has
been Detected C-3
E-l Measured Reaeration Coefficient Ratios for
High-Volatility Compounds E-6
xii
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ACKNOWLEDGEMENTS
The Arthur D. Little, Inc., task manager for this study was
Diane Gilbert. Contributing authors were Caren Woodruff, Alan
Preston and Richard Thomas (Fate), Melba Wood (Monitoring),
William Steber (Human Health Effects), Diane Gilbert (Human
Exposure and Risk), and Melanie Byrne (Aquatic Effects and Expo-
sure). Editing was performed by Laura Williams and documentation
by Nina Green. The chapter on Materials Balance was written by
Kenneth Moss, Robert DeRosier, and Patricia Cruse of Acurex Corp.
and directed by Kenneth Moss.
xiii
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1.0 TECHNICAL SUMMARY
The Monitoring and Data Support Division, Office of Water Regulations
and Standards of the U.S. Environmental Protection Agency is conducting
risk assessments for pollutants that may enter and traverse the environ-
ment thereby leading to exposure to humans and other biota. The program
is in response to Paragraph 12 of the NRDC Consent Decree. This report
is a risk assessment for toluene using available data and quantitative
models where possible to evaluate overall risk.
1.1 MATERIALS BALANCE
Toluene is a highly volatile, colorless, aromatic liquid extracted
primarily from petroleum and its products, and, to a lesser extent, from
coal and coal products. Only 11% of the total production in 1978
(31,816,000 kkg) was isolated as pure toluene. The remaining 89%
(27,&00,000 kkg) is contained in gasoline, coal-derived light oils and
tar, and catalytic reformate. Production of toluene results in esti-
mated environmental releases of 4800 kkg, mostly to air.
Uses of toluene totaled 31,000,000 kkg; of this amount 92% was used
in gasoline and 1% of the total supply was used as a solvent (77, in
chemical synthesis). Toluene is used to synthesize benzene, toluene
diisocyanate, and benzoic acid, among other organic chemicals. As a
solvent, it is used in paints, inks, adhesives, cleaning agents, etc.
Estimated environmental releases are primarily (99.7% of total re-
leases) to the air (1,100,000 kkg); 63% of which results from the dis-
tribution, vending and use of gasoline. Solvent use accounts for about
one-third (370,000 kkg) of air emissions; manufacturing uses are respon-
sible for about 0.1%. Estimated water discharges totaling 1200 kkg
(0.11% of total toluene releases) are mostly (89%) due to spills of
gasoline, oil, and toluene to surface waters. The remaining water dis-
charges (118 kkg) originate from solvent uses, coal coking, POTW effluents,
and wood preserving. Estimated releases to land totaling 1300 kkg consti-
tute 0.12% of total environmental releases and are mainly (74%) a result
of production (petroluem refining and coking operations).
Inadvertent sources, such as spills during transport of toluene,
stationary fuel and coal refuse pile combustion, forest fires, etc.
contributed about 33,000 kkg to the environment; 96% of which was released
to the atmosphere.
1.2 ENVIRONMENTAL FATE
The dominant fate processes for toluene involve intermedia transfers
to the atmosphere, where it undergoes oxidative destruction by hydroxyl
radicals, a process with a half-life of less than two days. Discharges
of toluene to land or water bodies will usually be followed by rapid
depletions in toluene levels, predominantly because of rapid volatiliza-
tion (half-life of 5 hours frcm water) and, to a much lesser degree,
1-1
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mlcrobial degradation under certain favorable conditions. Within soils,
toluene may also be immobilized as a result of sorption onto organic
matter; the rate of volatilization from soil has not been reported.
Toluene moves rapidly through some soils, however, and has the potential
to reach groundwater and consequently enter drinking water supplies.
Toluene has been found in water, air, sediments, and foods. In
surveys made within the last five years, it has been detected in both
surface and groundwater drinking supplies. It has been detected in 11%
of the 236 surface supplies tested with a mean value of 0.15 yg/1. The
highest observed level was 19 yg/1. Groundwater data are less well
documented; however, in the U.S. EPA's Community Water Supply Study,
toluene was detected in only 2 of 305 supplies. The maximum observed
groundwater concentration was 100 yg/1 in a well reported in STORET;
however, most observations were less than the detection limit (0.5 -
5 iig/1).
In ambient surface waters, 48% of the positive values were less than
10 ug/1 of toluene, with 14% of the samples above 100 yg/1. Toluene was
observed in samples from 14 of the 15 water basins in the continental
United States. Samples of industrial or other effluent discharges taken
in 11 of these basins (17 states) showed a similar distribution, with a
maximum of 4600 yg/1 reported.
Samples of toluene in foods are quite limited. It has been measured
in fish, nuts, potatoes and grape essence; however, the data are insuffi-
cient to indicate typical levels. It has been documented in cigarettes,
however, with a net yield of about 0.1 mg/cigarette.
Atmospheric levels of toluene measured in urban areas averaged about
19 ug/a3 and ranged from trace to 283 ug/m . Rural and remote areas, on
the other hand, averaged about 1 yg/m and ranged from "trace" to 57 yg/m .
It appears that the mobile sources of toluene are the dominant cause of
the observed air levels. However, some studies suggest that volatilization
from gasoline is a significant source in addition to vehicle exhausts.
1.3 HUMAN HEALTH EFFECTS AND EXPOSURE
Toluene is a general, central nervous system (CNS) depressant, with
a low toxicity. Its acute CNS effects that occur at high levels of
exposure (often as a result of solvent abuse), include euphoria, ataxia,
loss of consciousness, vomiting, tachycardia, and lead to respiratory
paralysis and death if the exposure continues.
Other toxic effects include cardiotoxicity (presumably arrhythmia
development), and possible permanent CNS damage and reproductive toxi-
city. With the exception of cardiotoxicity, these latter effects are
difficult to ascribe to toluene exposure alone, because other organic
solvents are usually present during human exposure episodes. Animal
studies and some preliminary human studies suggest weak evidence of re-
productive toxicity. However, further research is required before the
1-2
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nature of the toxicity, toxic levels, and possible threshold levels
can be identified.
The data base on the potential carcinogenicity of toluene is limited
and inadequate for quantitative estimations of human risks. Presently
available data indicate no toluene-induced carcinogenic or mutagenic
effects in experimental animals. The U.S. EPA (1980b) has also stated
that available oncogenic data are insufficient to evaluate the carcino-
genic potential of toluene.
Human exposure to toluene may occur through ingestion, inhalation,
and through the skin. Typical exposures (reported as per capita values)
encountered in drinking water are about 0.5-3 yg/day. Insufficient data
exist to assess toluene ingestion in foods. However, fish consumption
may result in the ingestion of 6.5 Ug/day toluene. The estimated max in urn
daily ingested amount is 38 ug for water and 224 yg for fish.
Inhalation levels are somewhat higher. An amount typical of urban
areas (150 million people potentially exposed, as of 1970) is 210 ug/day,
while rural areas (54 million people potentially exposed, as of 1970) are
usually an order of magnitude less — 11 ug/day. Nor.occupaticnal exposure
at gasoline stations can contribute 10 ug to the daily intake of toluene.
Cigarette smoking (54 million smokers, as of 1978) appears to have the
highest exposure potential with an average smoker (30 cigarettes/day)
receiving a 1560 ug/day dose. Extreme inhaled doses are as high as
3170 ug/day for urban residents. Occupational exposure at the OSHA
standard may be as high as 3,600,000 ug/day.
Percutaneous exposure is possible as a result of the use of consumer
products. A 5-30 minute exposure for both hands in a 5% liquid toluene
solution could result in an estimated intake of 200-1000 ug/per use.
Assuming a use rate of once per week, the estimated average daily exposure
would be 23-140 ug. Occupationally-exposed individuals, similarly exposed
to pure liquid toluene might receive 3200 ug per use over the same time
period.
1.4 AQUATIC EFFECTS AND EXPOSURE
Aquatic organisms exposed to toluene may experience changes in gill
permeability and internal C02 poisoning. The majority of acute toxic
effects to fish and invertebrates occurs in the 10.0-100.0 mg/1 range.
The most sensitive species tested is the striped bass (LC$Q = 6.3 mg/1)
and the most resistant, the mosquito fish (LC^Q > 1000 mg/1). Data on
environmental factors affecting the toxicity of toluene are not extensive;
however, neither temperature nor water hardness has been found to have a
significant effect. Based upon the limited toxicity data, no water
quality criteria for aquatic life has been set for toluene.
1-3
-------
Of Che total amount of toluene discharged to the environment
annually in the United States, less than 1% is directly discharged to
water. Monitoring data indicate that the mean concentration of toluene
in ambient and effluent water in 16 major river basins is less than
10 ug/1; 48% of the positive values in ambient waters were below this
value. About 14£ of the positive values exceeded 1.0 mg/1, which
indicates chat some potential for risk to aquatic systems exists.
1.5 RISK CONSIDERATIONS
The data base on the potential careinogenieity of toluene is limited
and inadequate for quantitative estimates of human risks. Presently,
available data indicate no toluene-induced carcinogenic or mutagenic
effects in experimental animals.
Toluene is widely dispersed in the human environment. However, the
fate processes affecting the toluene released to the environment favor
atmospheric destruction. In order to estimate the margins of safety for
human populations at possible exposure levels, the latter were compared
with the threshold limit value (TLV) of 100 ppm (377 mg/ar). The TLV
was calculated to permit an absorption of 1.8 gr/day. Because this
intake level was lower than the several no-observed-effect levels
determined from animal experiments, it was used as a conservative basis
for estimating margins of safety.
Margins of safety were calculated by dividing the daily absorbed
dose at the TLV by the daily absorbed dose at the various nonoccupational
exposure levels. As described in Section 5.1, human effects are assumed
to depend on absorbed dose rate (e.g., mg/day) and not on exposure route.
The lowest margin of safety for typical nonoccupational exposure to toluene
is 1200 for cigarette smoking. Ingescion of toluene in drinking water was
associated with margins of safety of at least 600,000, and more typically,
1,000,000. Inhalation of average levels of toluene in urban areas has a
safety margin of 9000 for average concentrations. Therefore, the risks
of adverse health effects resulting from exposure to toluene in water and
air at commonly found levels, and from extreme levels less frequently
observed are small.
Risks to aquatic biota are considered low because less than ten
occurrences of toluene in ambient and effluent waters have been reported
at concentrations in the range of known acute or chronic effects for
aquatic organisms (1-10 mg/1). It is presumed that these levels result
from localized discharges; thus no long-term effects to individual spe-
cies, communities, or aquatic ecosystems are expected. Short-term
effects on certain species may occur; however, these have not been
documented in the natural environment.
1-4
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2.0 INTRODUCTION
The Office of Water Planning and Standards, Monitoring and Data
Support Division of the Environmental Protection Agency is conducting
a program to evaluate the exposure to and risk of 129 priority pollutants
in the nation's environment. The risks to be evaluated included potential
harm to human beings and deleterious effects on fish and other biota.
The goal of the task under which this report has been prepared is to
integrate Information on cultural and environmental flows of specific
priority pollutants and estimate exposure of receptors to these sub-
stances. The results are intended to serve as a basis for developing
suitable regulatory strategy for reducing the risk, if such action is
indicated.
This document is an assessment of the exposures and risks associated
with toluene in the environment. It includes summaries of comprehensive
reviews of the production, use, distribution, fate, effects and exposure
to toluene and the integration of this material into an analysis of
risk.
Toluene is an aromatic, volatile, colorless liquid extracted primarily
from petroleum and to a less extent from coal. Use as well as derivation
of petroleum and petroleum products (i.e., gasoline and solvents) result
in environmental releases of toluene as it may be a contaminant. The
materials balance for toluene is described in Chapter 3.0.
The physical and chemical behavior of toluene is described in
Chapter 4.0. Its properties are documented in the first section, fol-
lowed by a compilation of monitoring data for all environmental media.
The results of media-specific fate and intermedia transfer model used
to predict concentration levels of toluene in the air and water within
close proximity to significant toluene sources and equilibrium concen-
trations resulting from free exchange of toluene between air, soil, water,
and sediments are presented next. A discussion of biodegradation of tol-
uene and a summary of critical fate pathways conclude the chapter.
The most current research of effects upon human and nonhuman
receptors, a description of the duration of exposure and the populations
exposed to documented or predicted levels of toluene and a statement
of risk comprise the later chapters of this report.
Presently, there are two sets of federal criteria for toluene:
occupational air standards and water quality criteria. In water, a
424 mg/1 has been set to protect humans from the toxic properties of
toluene if only contaminated aquatic organisms are consumed. If both
contaminated water and aquatic organisms are in the diet, the human
health water quality criteria is 14.3 mg/1 (U.S. EPA 1980).
2-1
-------
The Occupational Safety and Health Administration has established
standards for the regulation of toluene in the workplace. The time-
weighted average concentration for 8 hours should not exceed 75& mg/nr
(200 ppm) (OSHA 1978).
Toluene concentrations in air were converted from ppm to mg/m by
using the following relationship: 1 mg/m = 3.77 ppm. This factor was
derived assuming 1 atm and 25°C, conditions, which were not absolute
for all atmospheric measurements. However, monitoring data are seldom
reported with the concurrent temperature and pressure; therefore, in
the absence of these data, the conversion factor was used unilaterally
for all values of toluene in air.
2-2
-------
REFERENCES
Occupational Safety and Health Administration (OSHA). OSHA Safety and
Health Standard 29 CFR 1910. U.S. Department of Labor, Washington, D.C.;
1978.
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for toluene. Washington, D.C.: Office of Water Regulations
and Standards; 1980.
2-3
-------
3.0 MATERIALS BALANCE
3.1 INTRODUCTION
This chapter presents data on the production and use of toluene, as
well as data on the releases of toluene to the environment. A summary
flow diagram of the toluene materials balance is presented in Figure 3-1.
These data provide a framework for constructing gross estimates of the
toluene distribution to and in the environment.
Direct production of toluene occurs by two routes, isolated and non-
isolated. Approximately 11%, or 3.4 x 106 kkg, of the total toluene
produced in 1978 was isolated from petroleum sources (catalytic refornate,
pyrolysis and gas and styrene manufacture) and coke ovens. In addition to
190,000 kkg contributed by imports, the remainder of the toluene input to
this 1978 materials balance (over 27 x 10" kkg) is accounted for by non-
isolated sources: catalytic reformate, pyrolysis gasoline, and coal
derived. The gasoline pool consumed approximately 92% of the toluene
supply, mostly from nonisolated sources, plus back blending from isolated
sources. The remaining 8% of the toluene supply was consumed in chemical
synthesis and solvent uses.
The major mode of toluene release is atmospheric emissions, which
reflect the low water solubility and high volatility of the compound
(see Figure 3-1). Air emissions from gasoline use comprised about 63%
(680 x 106 kkg) of all air emissions and released toluene, which had,
for the most part, never been isolated as such. The next largest source
of emissions, solvent use, accounted for 34% (370 x 103 kkg) and the use
of toluene for chemical manufacturing accounted for only 0.07% (840 kkg).
Identified water discharges were primarily (89%) from toluene, oil
and gasoline spills to surface waters, considered in the report as an
inadvertent source. The remainder of the water discharges resulted from
solvent use, coal coking operations, POTW effluent discharge, and wood
preserving.
Transportation spills also contribute a significant percentage (19%)
of the estimated toluene releases to land. However, the major source of
land release of toluene (74% or 970 kkg) appears to be from production
(petroleum refining and coking operations). An additional 8% comes from
POTW sludge.
3.2 PRODUCTION OF TOLUENE
Toluene is produced from petroleum and coal, although it may not
necessarily be isolated from the resultant product. This section will
discuss toluene production from both these sources, the associated
environmental releases, and releases from inadvertent sources. Toluene
production from isolated and unisolated sources is presented in Table 3-1.
3-1
-------
RilMiti CO
3
lOHSOUTtO:
Und «lr
POTW
»«Ul 11.000
11.8BC
**ll vitm
*S*t TMli 1-2.
J-l. TaliMfi* MUrlilt lilincc (10J kkg)*
blimi Inffcitt
-------
Environmental Releases (ID3 kkg)c
Inadvertent Sources
Transportation Spills
Production
Proeylene Oi-.ae
Polycnloraorene
itnylene - Presvlem
Rubber
ttiylene • Propyleni
Terrolymer
Insulation Board
1
|
•crylonitrile _
Comoultion
Stationary Fires
Agricultjral Burning
Structural Fires
Miscellaneous
1 Cigarette Snoke
Wood Preserving
0«»r
Totals
!
!
-*
1 .
_| '
^
i.ano
9.23
0.011
1.3
Air
0.036
0.46
0.09
4.2
9.359
4.4
13.3
7.0
1.0
<1
O.OS3
0.008
1100
Water
3.4
0.68
0.0022
neg
neg
0.0063
1.2
c No POTW >eleases from inadvertent sources were identified.
Figure 3-!. (Concludes)
3-3
-------
Table 3-1. Toluene Production, 1978 (kkg/yr)
Source
Isolated
Catalytic Reformate
Pyrolysis Gasoline
Styrene Manufacture
Coke Ovens
Imports
Exports
SUBTOTAL
Nonisolated
Catalytic Reformate
Ryrolysis Gasoline
Coal Coking:
Nonprocessed light oil
Nonrecovered light oil
Coal tar
SUBTOTAL
TOTAL
Quantity3
3,110,000
324,000
135,000
26,000
192,000
-364,000
3,400,000
27,100,000
197,000
52,000
22,000
22,000
27,393,000
30,816,000d
Environmental Releases'3
Air Water Land POTW
310
290
103
33
740
2,700
180
21
2.9
8.9
2,900
3,600
neg
neg
(c)
(c)
neg
neg
neg
35
15
15
65
65
93
9.7
4.1
neg
(c)
(c)
110
810
5.9
23
9.8
9.8
860
970
26
11
11
48
48
Sources: SRI, 1979 and USITC, 1979
aSee Appendix A Notes and Tables A-l, A-2 and A-3 for references
and calculations.
Blanks indicate data not available.
cSee Section 3.2.4, transportation spills.
dValues may not add due to rounding.
3-4
-------
3.2.1 Production of Isolated Toluene
Only 11% of the toluene produced is isolated as such. Although
crude oil contains low concentrations of toluene (1.3% by weight; Green
and Morrell, 1953), it is isolated only frora catalytic reformats, pyroly-
sis gas and as a by-product of styrene manufacture. Less than 1% of the
total toluene produced is coal derived.
3.2.1.1 Catalytic Reformate
Of all toluene produced (isolated and nonisolated) in 1978, about 10%
or 3.1 x 10° kkg was derived from catalytic reformate (SRI 1979, see Appen-
dix A notes). Catalytic reformate is produced by catalytically dehydro-
genating selected petroleum fractions to yield aromatic hydrocarbons.
Although the concentration of toluene in catalytic reformate ranges fron
14 to 27%, this report will use a toluene content of 20% (SRI 1979) for
estimation purposes. The 1978 catalytic reforming capacity for toluene
production was about 4.6 x 10& kkg (SRI 1979). The locations, capacities,
production, and emissions for plants that produce toluene directly from
petroleum feedstocks are listed in Table A-4 (Appendix A).
3.2.1.2 Pyrolysis Gasoline
About 1% (324 x 10^ kkg) of total 1978 toluene production was derived
from pyrolysis gasoline (SRI 1979, see Appendix A notes). Pyrolysis gas-
oline is a by-producc from the cracking of hydrocarbon feeds to form
olefins. The yield of toluene from pyrolysis gasoline is a function of
the feedstock and the severity of cracking (see Table A-5, Appendix A).
Toluene production may vary from 1 to 145 kg/kkg ethylene (SRI 1979).
The estimated annual capacity for toluene production from pyrolysis gas-
oline is 447 x 103 kkg (SRI 1979). The locations, capacities, production,
and estimated environmental releases for the facilities are presented in
Table A-4 (Appendix A). Fyrolysis gasoline is either processed for
aromatics recovery or blended into gasoline, although some companies
sell the pyrolysis gasoline.
3.2.1.3 Styrene Manufacture
About 0.4% (135 x 103 kkg) of all toluene produced in 1978 was pro-
duced as a by-product of styrene manufacture (SRI 1979, USITC 1979, see
Appendix A notes). When ethylbenzene is dehydrogenated to produce styrene,
0.04-0.07 liter of toluene per kg styrene is produced as a by-product.
The locations, toluene production, styrene production capacities, and en-
vironmental releases for the plants are presented in Table A-6 (Appendix A).
3-5
-------
3.2.1.4 Coal Sources
Toluene production from coal amounted to 0.08% (26 x 10^ kkg) of the
total (USITC 1979). When coal is carbonized to produce coke, about 10.6
liters of light oil are produced per kkg coal carbonized. This light oil
may be isolated and processed to recover the toluene it contains (12-20%
by volume) (SRI 1979, U.S.* DO I 1976). If the light oil is not processed
for aromatics recovery, it may be burned as fuel, used as a solvent for
phenolics recovery, sold to tar distillers or petroleum refiners to be
added to gasoline or used for aromatics recovery. Approximately 30% (by
capacity) of the coke oven operators recover toluene from light oil,
even though 90% practice light oil recovery (EPA 1979b). The coke plants
that recover light oil are listed in Table A-7 (Appendix A).
3.2.1.5 Exports and Imports
Exports and imports of toluene (in 1978, were 384 x 103 kkg and 192 x
103 kkg, respectively (USITC 1979). Environmental releases from this
category are covered as spills under inadvertent sources (Section 3.2.4).
3.2.2 Nonisolated Toluene
Approximately 89% (27 x 106 kkg) of the toluene produced in 1978
was not isolated as such. Nonisolated toluene is derived from catalytic
reformate, pyrolysis gas, and coal coking operations.
3.2.2.1. Catalytic Reformats and Pyrolysid Gasoline
Approximately 27.1 x 10*> kkg of toluene were contained in catalytic
reformate in 1973 (SRI 1979, USITC 1979, see Appendix A notes for calcu-
lations) . Most of this is blended into gasoline to improve the octane
rating. Pyrolysis gasoline that is not processed for toluene recovery
may also be used for this purpose. An estimated 197 x 103 kkg of unre-
covered toluene was contained in pyrolysis gasoline in 1978 (SRI 1979).
3.2.2.2 Coke Ovens
Coke oven light oil is recovered by 90% of the coke oven operators.
This amounted to 612 x 10^ liters, of which 238 x 10° liters were processed
to produce various chemicals. Assuming that the unprocessed oil has a
toluene content of 16% by volume, 52 x 10-* kkg of toluene were contained
in this source (U.S. DOE 1979, SRI 1979). From the remaining 10% of the
coke oven plants that do not recover light oil, an estimated 22 x 103 kkg
of toluene were contained in the oil (see Appendix A notes).
Coke oven tar is another source of unlsolated toluene. Although some
toluene is produced by distillation of the tar, it is also burned as fuel
or kept for other uses. The estimated total amount of toluene contained
in coke oven tar was 22 x 103 kkg (see Appendix A notes).
3-6
-------
3.2.3 Environmental Releases
Toluene releases may arise from process losses, fugitive emissions,
or storage losses from production; these data are presented in Table 3-1.
The emission factors used are presented in Table A-l (Appendix A, EPA
1980d). Releases shown from each source are from production of both
isolated and nonisolated toluene (see Appendix A). Discharges to water
from petroleum refineries are assumed Co be negligible, because toluene
was not detected in 10 of 11 samples and was present at levels below the
quantification limits (1-10 ug/1) in only one sample (EPA 1979g). Re-
leases calculated from coking operations are based upon the disposition
of effluents from coking operations (Table A-3) as well as the emission
factors presented in Table A-l (EPA 1979h, EPA 1980d). Water recycled
to quenching operations is arbitrarily assumed to release its toluene
equally to land and air. Releases from imports and exports are covered
in transportation spills (Section 3.2.A).
3.2.4 Inadvertent Sources
Because of the widespread and voluminous use of petroleum- and
coal-derived oils, fuels and solvents that may contain toluene, it is
difficult to quantify all the inadvertent sources of release to the
environment. A list of the major contributing sources is presented in
Table 3-2 and the derivations of the data are discussed in Appendix A.
Note that the majority of toluene releases are to the atmosphere. Com-
bustion, however, contributes over 80% of the atmospheric emissions of
toluene. Furthermore, about 35% of this figure is comprised of uncon-
trolled sources, such as forest, agricultural, and structural fires.
The inadvertent release of toluene from manufacturing processes
occurs primarily from three sources: feedstock contamination; by-
product formation; presence in oils used in processing or in control of
waste emissions. The latter source is exemplified by acrylonitrile
manufacture, where oils are layered on waste ponds to control the release
of other volatile organic pollutants. Ethylene-propylene rubber and
terpolymer manufacture utilize extender oils, which can contain toluene,
to improve the viscosity of the elastomer (see Appendix B, Table B-l).
The estimated 53-kkg of toluene released in sidestream smoke from
cigarettes is small in comparison to the other inadvertent sources.
However, this represents a widespread source, with a potential for high
exposure among the population subgroup that either smokes or is often
in contact with smokers.
3.3 USES OF TOLUENE
This section includes information on the consumption in the U.S. of
toluene and environmental releases from these uses. Toluene uses are
grouped into three main categories: gasoline, chemical synthesis, and
solvent. The following is a brief discussion of each, while environmental
releases from uses are summarized in Section 3.3.". Table 3-3 is a summary
materials balance for the various use categories.
3-;
-------
Table 3-2. Inadvertent Sources of Toluene Releases to the Environment. 1978*
Source
Environmental Releases (kkg)
Air Water Land
u>
00
Transportation Spills
Oil
Gasoline
Toluene
Propylene Oxide - Chlorohydrin Process
Polychloroprene
Ethylene - Propylene Rubber Manufacture
Ethylene - Propylene Terpolymer Production
Wood Preserving
Insulation Board Manufacture
Wet - Process Hardboard Manufacture
Acrylonitrile Manufacture
Combustion of Coal Refuse Piles
Stationary Fuel Combustion
Forest Fires
Agricultural Burning
Structural Fires
Cigarette Smoke
Other0
TOTAL
36
460L
90
4,200
,b
400
680
2.2
5.6
230
11
6.3
neg
neg
1100
250
aSee Appendix A for derivation of figures in this Table. All values are rounded to two significant figures.
bSource: EPA, 1978b.
Includes releases from production of Malathion, Dimethoate and Ronncl.
-------
3.3.1 Gasoline
As mentioned in Section 3.2, nost of the toluene used in gasoline
is never isolated, but rather is a component of various refinery streams,
primarily catalytic refornate. Isolated toluene can also be back-blended
into the gasoline pool for improvement and adjustment of its antiknock
quality (octane number). A total of 28.5 x 106 kkg (92% of the total
U.S. toluene demand) was consumed for use in gasoline in 1978, 26 x 106
kkg of which had not been recovered but instead blended directly as part
of a benzene-toluene-xylene (BTX) stream.
3.3.2 Chemical Synthesis
Use of toluene as raw material for various chemical manufacturing
processes utilized approximately 7% (2.2 x 10^ kkg) of the total toluene
produced in 1978. The flow charts in Appendix D describe the major
synthetic pathways that utilize toluene as the basic building block.
3.3.2.1 Benzene
1 Benzene production via hydrodealkylation uses 1.7 x 10 kkg toluene
or 5.5% of total toluene production, and is the major use of toluene in
chemical synthesis. The producers, locations, capacities, toluene
consumption, and environmental releases relating to benzene production
from toluene are listed in Table 3-4.
Approximately 20-25% of the benzene supply is derived from dealky-
lation. The contribution of this source varies in response to benzene
demand and toluene demand for other uses (e.g., gasoline). The average
yield for benzene is about 94%, corresponding to 1.1 kkg toluene required
per kkg benzene produced (SRI 1979).
3.3.2.2 Manufacture of Toluene Diisocyanate
The manufacture of toluene diisocyanate (TDI) consumes 2 x 10^ kkg
or 0.6% of the 1978 total toluene produced (SRI 1979). Toluene diiso-
cyanate is used in urethane polymers, primarily for flexible foams in
furniture cushions. The producers of toluene diisocyanate, their loca-
tions and plant capacities are presented in Table 3-5.
In TDI manufacture, toluene is nitrated to dinitrotoluene, which is
catalytically reduced to toluene diamine (see Appendix D). Toluene
diamine is then phosgenated to the final TDI product. Approximately
0.7 kkg toluene is consumed per kkg TDI produced (SRI 1979).
3-9
-------
Table 3-3. Toluene Materials Balance: Uses. 1978 (kkg/yr)a
Use
Gasoline
Non-Recovered
Back Blended
Solvent Uses
Paint and Coatings Solvent
Adheslves, Inks, Pharmaceu-
ticals, Others
Chenlcal Synthesis
Benzene
Toluene disocyanate
Benzole Acid
Benzyl Chloride
Xylene Disproportionate
Vinyl Toluene
p-Cresol
Toluene Sulfonates
Benzaldehyae
Trlchloro toluene
Toluenesulfonyl Chloride
Para-t-Sutyl-Benzolc Acid
Other
Input5
27,OCO,OOoJ
1,500,000T
260,000
h
130,000"
1.700,000
200,000
66.000
36.000
99,000
25.000
6.600
5,500
3,400
5,400
6,300
2.300
2.000
Environmental Releases
Airc Water Land
r 680,000e neg neg
260. OOO9 neg9 neg9
h 1
110,000" 30
360
260
99
36
20
25
13
4.1
13
J
•nee
»
Total 31,000,000 1,050,000 30 neg
aA11 values rounded to two significant figures; blank spaces indicate data not available.
"Source: SRI, 1979.
cSource: E»A, 1930d.
99S from catalytic reformats.
Includes 19,000 kkg from marketing; 13,000 Jckg evaporative loss during use; 640,000 kkg
from auto exhaust. See Appendix A"for derivations.
Primarily from styrene manufacture and pyrolysis gasoline.
9A11 Is assumed released to the atmosphere (EPA, 1980d).
15S is assumed used as fuel, with the remainder emitted during use (EPA, 1980d). We
assume that 6.100 kkg/yr emitted from solvent evaporated during decreasing (EPA, 1978b)
Is included In this emission total.
See Table 3-7 for breakdown by Industry.
3-10
-------
Table 3-4. Toluene Consumption and Environmental Releases: Oenzene Production. 1978 (kkg/yr)a
Company
American Petrofina
Ashland Oil
Coastal Stales
Coninonweal th
Crown
Dow
Gulf
Nonsanlo
Phillips
Quintana-Howel!
Shell
Sun
Total
Location
Port Arthur. TX
Dig Spring. TX
Catlettsburg. KV
Corpus Christ!, TX
Penuelas, PR
Pasadena. TX
Freeport, TX
Alliance. LA
Philadelphia. PA
Alvln. TX
Guayama, PR
Corpus Christl. TX
Odessa, TX
Corpus Christl. TX
Toledo, Oil
Tulsa, OK
Benzene .
Capacity0
77.000
130.000
120.000
200,000 '
300.000
77. 000
84 .QUO
1 GO .000
67,000
130.000
270.000
250.000
2.1.000
67.000
210.000
50.000
2".~3oOoo
Toluene
Used
59.000
100.000
91.000
160.000
300.000
59.000
65.000
120.000
52.000
100.000
210.000
200.000
18.000
52.000
160.000
30,000
1. BOO .000
Environmental Releases
A1rc Water Land
12
20
in
32
60
12
13
24
10
20
42
40
3.6
10
32
7.n
360
aAll values rounded to two significant figures; blank spaces indicate data not available.
SRI. 1979. Toluene use based on 1.23 kkg toluene required per kkg benzene produced; data exclude toluene disproportionate.
Plants are assumed to operate at 62-632 of capacity.
cEinission factor and breakdown: sec Appendix A. Tiible A-l.
-------
3.3.2.3 Other Chemical Intermediate Uses
The remaining major uses of isolated toluene in chemical synthesis
(see Table 3-3) include the manufacture of xylanes by disproportionation
(99,000 kkg), benzoic acid (66,000 kkg), benzyl chloride (36",000 kkg),
vinyl toluene (25,000 kkg), benzaldehyde (8400 kkg) and p-Cresol (6600
kkg). Each of these uses accounts for less than 17, of the total
toluene supply. Xylenes have well-known uses in the gasoline pool and
as solvents. Benzoic acid is used as a chemical intermediate, chiefly
in the manufacture of phenol. Most of the benzyl chloride produced is
used to manufacture PVC flooring plasticizers or benzyl alcohol. Vinyl
toluene is used in resin manufacture. Benzaldehyde is utilized in the
manufacture of perfumes, dyes, flavorings, and Pharmaceuticals; and
p-Cresol is used primarily to manufacture 2,6-di-tert-butyl-p-cresol (BHT).
The producers, capacities, locations, toluene consumption, and
estimated environmental releases for these chemical manufacturing uses
are presented in Table 3-6. In addition, Appendix D details the various
reaction pathways for each, as well as for some of the minor chemical
end products, including: toluene sulfonyl chloride (raw material for
saccharin); toluene sulfonates (used as a surface active agent in
powder detergents, heavy-duty liquids); trichlorotoluene or benzotri-
chloride (organic synthesis, dye intermediate); para-t-butyl-benzoic
acid (resin manufacture intermediate); dodecyltoluene (precursor in
germicide manufacture); and nitrotoluenes (dye intermediates). The last
military facility to produce trinitrotoluene (TNT) closed down in 1977.
3.3.3 Solvent Uses
Approximately 10% (390,000 kkg) of the isolated toluene supply was
utilized as solvents in 1978 (SRI 1979; see Table 3-3). This total is
divided between paint and coating carrier solvents (260,000 kkg) and
formulation or cleaning solvents in the adhesives, ink, pharmaceutical
and other industries (130,000 kkg). The wide scope of toluene applica-
tions as a formulation solvent can be seen in the list of commercial
products containing toluene, presented in Appendix B (see Table B-2).
The volatile nature of toluene facilitates its use as a fast-drying
cleaning (e.g., cold cleaning degreasing) or carrier (e.g., paints,
inks, leather finishing) solvent. The pharmaceutical industry uses
toluene as a raw material in production processes, and as an anthelmin-
thic agent against roundwonns and hookworms, primarily in domestic dogs
(Krinsky 1980).
3-12
-------
Table 3-5. Toluene Releases from Toluene Diisocyanate Producers. 1978 (kkg/yr)a
Company
Allied Chemical
BASF Wyandotte
DOM Chemical
UuPont
Mohtty Chem. Corp.
01 In Corp.
Hub icon Chems. Inc.
Union Carbldef
Total
Location
Hounds vllle. WV
Geismar, LA
Freeport. TX
Deepwater. NJ
Bay town, TX
New Mdrtlnsvllle. WV
Ashtabula, Oil
Lake Charles. LA
Geismar, LA
S. Charleston. MV
TDIb
Capacl ty
36.000
45.000
45.000
32.000
59.000
45. COO
14.000
45.000
18.000
25.000
360.000
Toluene0
Use
20.000
25,000
25.000
17.000
. 32.000
25.000
7.300
25.000
10.000
13.000
200.000
Environmental Releases
A1rd Water Land6
26 i
32
32
22
41
32
9.3
32
13
17
neg
260'
aAll values rounded to two significant figures; blank spaces Indicate data not available.
bSource: SRI. 1979.
C0ased on 0.7 unit of toluene consumed per unit of 1DI produced, and TDI produced at 79X of capacity (SRI. 1979); usage
distributed per capacity.
[mission factor and breakdown: see Appendix A. Table A-5.
eLess than o'ne kkg. Based on 55H kkg centrifuge residue per plant, probably no more than 100 ppm toluene, by analogy
to dlchlorobenzene (EPA. 1977c.d; Lewis. 1975).
Union Carbide Corp. permanently shut down this plant In December. 19711. Tims, the production profile for TDI and toluene
consumption shown do not reflect today's market.
-------
Table 3-6. Toluene Consumption and Environmental Releases from other Toluene Chemical Intermediate Users. 1976 (kkg)a
!-•
*-
Company
Monsanto
Slauffer
UOP, Inc.
Total
Kalama
Monsanto
Velsicol
Pfi/er
Tenneco
Total
Location
Bridgeport, NV
Sauget. IL
Edison. NJ
E. Rutherford. NJ
Kalama. WA
St. Louis. MO
Beaumont. TX
Chattanooga, TN
Terre Haute, IN
Garfield. NJ
Production
Canac i ly
Benzyl Chloride
36.000
36.000
5.400
1,400
79.000
Benzole Acid
63.000
4.500
23.000
27.000
2.700
§.(100
fiolodo
Toluene
Used
Producers
16.000
16.000
2.700
450
357600
Producers
33.000
2.300
12.000
14 .000
1.400
3.200
667000
Environmental Releases
Airc Water Land
16
16
2.7
1.0
~36
50
3.5
in
21
2.1
4.H
~99
Xylene Dlsproportionatlon Producers
AltCO
Sun
Total
Dow Chem. Corp.
Houston, TX
Marcus Hook. HA
Midland. Ml
89.000
92,000
T01 .000
Vinyl Toluene
27.000
48.000
50.000
98.000
Producer
25.000
9.6
10
"20
25
p-Cresol Producer
Sherwin Williams
Kalauia
Stauffer
Tenneco
UOP
Total
Chicago. IL
Kalama. WA
Eddys tone, PA
Edison. N.)
Garfield. NJ
E. Rutherford. NJ
Uenzalilehyde
6.600
Producers
.680
.6110
,6110
.61)0
.jjjflO
8.400
13
2.5
2.5
2.5
2.5
2.5
13
Source: CPA. 1980d.
All values rounded.^ blank spaces Indicate data not available.
See Appendix A. Table 3-6 for derivation of consumption.
Sue Appendix A. lable A-1 for emission tcicturs ami lireak-iuun.
-------
3.3.4 Environmental Releases
The environmental releases of toluene resulting from its use are
summarized in Table 3-3. The toluene release factors and other infor-
mation necessary to derive these totals are presented in the Appendix A
notes (as cited in Table 3-3) and Tables 3-4, 3-5, and 3-6, which list
environmental releases from specific chemical producers (i.e., benzene,
TDI, and other chemicals, respectively). Table 3-7 summarizes flow data
and toluene loading to water from various industries and Table 3-8 is a
regional breakdown of toluene emissions during gasoline marketing.
Appendix C contains two tables listing industrial wastewaters in which
toluene has been detected, and the frequency of occurrence. Finally,
Appendix D diagramatically presents the location of environmental re-
lease points from the chemical synthesis uses of toluene.
Two aspects of toluene environmental releases during use are most
striking: the large contribution to air emissions from gasoline and
solvent use and the low levels of release to water and land, although
data are limited. The 680,000 kkg of toluene released from gasoline
use is the sum of 19,000 kkg from marketing losses (see Table 3-8),
18,000 kkg evaporative emissions during use and 640,000 kkg from auto-
mobile exhaust. These emissions are based on information presented in
Appendix A (Section 3, Table 3-3). The total amount of toluene used in
paints and coatings is assumed completely volatilized during application.
Approximately 15% of the toluene marketed for use in adhesives, inks,
Pharmaceuticals, and others is estimated to be used as fuel, with the
remainder emitted (EPA 1980d). For purposes of this materials balance,
it is assumed that the 6100 kkg toluene emitted from degreasing opera-
tions (EPA 1978b) are included in this 110,000 kkg total.
The dearth of quantitative water and land release data is at lease
partially a function of the fact that toluene is a volatile compound.
The available information, however, indicates that toluene is present
in a number of industrial wastewater streams (see Appendix C, Tables C-l
and C-2), although the total annual loading is probably low (see Table
3-7; Appendix C, Tables C-l and C-2). Similarly, the only information
on land releases of toluene, from TDI manufacture, shows a negligible
amount of toluene disposed to land in centrifuge residue (see Table 3-5,
footnote "e").
3.4 MUNICIPAL DISPOSAL OF TOLUENE
This section deals with the ultimate disposition of toluene dis-
charged to municipal waste facilities. The latter include publicly
owned treatment works (POTWs) and urban refuse landfills or incinerators.
3-15
-------
Table 3-7. Wastewater Loadiny of Toluene: Various Industries
u>
Industry
Ink Formulating
Textile Products'1
Guin and Wood Chemicals
Paint Formulating*1
Leather Tanning
Pharmaceutical1*
TOTAL
Was tewa let-
Concentration (ug/l)
1.600C
14e
2.000*
990e
78C
515
Has tewa ter
Flow
(106 I/day)
0.092
2.000
Cl.ll9
2.0
200
250
Percent
Occurrence
87
46
7B
87
25
62
Mass Loading*
(kkg/yr)
0.038
3.8
0.0&2
0.72
1.2
24
30k
aliased on a 300 day operating year.
bAll data from EPA. 1979a.
cUntreated was tewa ter.
All data from EPA, 1979b. except percent occurence (EPA. 1980a).
eTreated Effluent.
All data from EPA. 1979c. except percent occurrence (EPA. 1980a).
9See Appendix A for derivation, based on production and flows In various Industry subcategorles.
''All data from EPA. 1979d.
All data from EPA, 1979e. except percent occurrence (CPA. IQBOa).
JA11 data from EPA. 1980b.
L
Values do not add due to rounding.
-------
Table 3-8. Toluene Emissions from Gasoline Marketing
Region
New England
Middle Atlantic
East North Central
West North Central
South Atlantic
East South Central
West South Central
Mountain
Pacific
Total
Number
of a
Sites3
11,105
28,383
42,270
23,304
37,286
16,313
28,336
12,815
26,647
226,459
Toluene
Emissions
(kkg/yr)D
920
2,300
3,500
1,900
3,100
1,400
2,300
1,100
2,200
19,000°
Source: EPA, 1980d.
Total number of service stations.
Based on 0.004735 kg hydrocarbon lost from gasoline marketing (bulk and service
stations)/kg gasoline consumed; it is assumed toluene is 1.26 wtS of the hydro-
carbon emission (GARB, 1975; EPA, 1975a).
cValues do not add due to rounding.
3-17
-------
3.4.1 POTWS
Input of toluene to POTWs largely depends on variations in indus-
trial discharges feeding the POTWs and the types of industry in a parti-
cular municipality. A recent EPA (1980e) study of selected urban PQTU
facilities with secondary treatment and varying feed conditions pro-
duced a materials balance of toluene shown in Table 3-9.
An overall materials balance, presented in Table 3-10, can be con-
structed using a total POTW flow of approximately 1011 I/day (EPA 1978c)
and median values of 30.5 ug/1 (influent) and 1 yg/1 (effluent) for
toluene (see Table 3-9). It is assumed, for purposes of these calcu-
lations, that influent and effluent flow rates are equal, i.e., that
water loss from sludge removal and evaporation are small compared to
influent flows. Using these assumptions, 37 kkg toluene were discharged
to water from POTWs in 1978, while there was an input of 1100 kkg (see
Table 3-10).
Toluene discharged in sludge can be estimated from the toluene
concentration in sludge and quantity of dry sludge produced annually,
6.0 x 10° kkg (EPA 19791). Assuming the median toluene concentration
of POTW wet sludge to be 833 yg/1, (see Table 3-9), and that wet sludge
is 95% water by weight, approximately 100 kkg of toluene are discharged
in sludge. As ocean dumping of sludge is mandated to cease by 1981
and assuming that more stringent air quality standards curb incinerator
use (EPA 19791), the 100 kkg of toluene contained in sludge are assumed
discharged to land.
The toluene released to the atmosphere may be estimated from POTW
data on influent versus effluent and sludge loadings, given the following
assumptions: (1) toluene recycled within the activated sludge process
will eventually be "wasted"; (2) the toluene biologically degraded is
negligible; and (3) toluene is lost to the atmosphere by mechanical
stripping, or aeration (note: volatilization is the primary environ-
mental transport mode for toluene). Thus, an estimated 960 kkg of
toluene is released to the atmosphere from POTWs.
3.4.2 Urban Refuse
The three options for handling urban refuse are energy recovery
(primarily by incineration), material recovery, and disposal through
incineration or landfills. Urban refuse can be divided into two major
components: a combustible fraction (paper, carboard, plastics, fabrics,
etc.) and a noncombustible fraction (ferrous and nonferrous metals,
glass, ceramics, etc.). There are no data, however, concerning
toluene emissions from municipal incineration, but toluene is probably
destroyed with over 99.9% efficiency (MacDonald et al. 1977). In formu-
lated products using toluene as a solvent, it is probably sometimes dis-
posed of directly as municipal waste. Although no data were available
on the total loading of toluene to landfills, it has been detected in
3-18
-------
Table 3-9. Toluene Distribution in POTWs and Sludge, Selected Urban Sites3
Plant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Median Values
Average Flow
(106 I/day)
340
30
42
320
83
27
190
87
200
87
160
150
64
53
27
550
57
240
260
450
Influent
28
5
15
36
37
191
15
229
• 8
12
50
23
10
73
4
33
72
34
60
22
30.5
Concentrations (ug/1)
Effluent
4
3
1
0
0
20
1
288
0
<1
2
7
<1
1
1
1
2
<1
3
<1
1
Sludge
NAd
336
54
984
199
423
4615
7635
1100
3000
5C3
14652
9500
26800
927
418
833
31
32 .
53
833
Source: EPA, 1980e.
^Percentage of flow contributed by industrial sources ranges from <1 to 35%.
"Composite grab samples, taken once every four hours, for 24 hours.
^Included primary and secondary sludge; grab sample.
available
3-19
-------
Table 3-10. Toluene Materials Balance: Municipal POTWs and Refuse (kkg/yr)
Source
POTWa
Urban
Incineration
Landfill
Input
noob
unknown
unknown
Air
960C
unknown
800e
Land
iood
unknown
unknown
Mater
37"
unknown
aPublicly Owned Treatment Works.
figures calculated from EPA data (sec Table 3-9): based on 1011 I/day total POTU flow and
median values for influent (30.5 pg/1) and effluent (1 ng/1) toluene concentrations.
V Mathematical difference between Input and Land and Water values.
o .
Based on a median value for wet sludge loading of toluene, 833 yg/1; wet sludge is 95% water by
weight; 6.0 x 10° kkg dry sludge produced annually (EPA, 19791; see Table 3-9).
eBased on 0.8 x 106 kkg/yr total hydrocarbons released from solid waste (EPA, 1979b); 0.1%
toluene (SCQAMD, 1979).
-------
air samples at a few sices (EPA 1980a). It is possible to estimate the
amount of toluene released to the atmosphere, based on 0.8 x 10° kkg/yr
total hydrocarbons released from solid waste (EPA 1977b). Assuming that
toluene comprises 0.1% of total hydrocarbons (SCQAMD 1979), a total
release of 800 kkg toluene/yr is estimated (see Table 3-10).
3-21
-------
REFERENCES
CARB, 1975, Source Reconcilation of Atmospheric Hydrocarbons. State
of California Air Resources Board, El Monte, CA, 1975.
Environmental Protection Agency, 1975a. A Study of Vapor Control
Methods for Gasoline Marketing Operations: Volume I - Industry Survey
and Control Techniques. Research Triangle Park, N.C.: EPA
450/3-75-046a;1975.
Environmental Protection Agency, 1975b. Compilation of Air Pollution
Emission Factors, Research Triangle Park, N.C.: AP-42, 2d ed., 1975.
Environmental Protection Agency, 1977a. Data on the Preliminary List
of Chemical Substances for Further Evaluation by the TSCA Interagency
Testing Committee. lERL-Cincinnati, OH: Organic Chemicals and
Products Branch, 1977.
Environmental Protection Agency, 1977b. Automotive Hydrocarbon
Emission Patterns and the Measurement of Nonmethane hydrocarbon
Emission Rates. EPA Mobile Source Branch, Research Triangle Park,
N.C.: EPA Mobile Source Branch, 1977.
Environmental Protection Agency, 1977c. Investigation of Selected
Potential Environmental Contaminants: Halogenated Benzenes.
Washington, D.C.: EPA 560/2-77-004;1977.
Environmental Protection Agency, 1977d. Alternatives for Hazardous
Waste Management in the Organic Chemical, Pesticides and Explosives
Industries. Washington, D.C.: EPA 530/SW-151c;1977.
Environmental Protection Agency, 1978a. Source Assessment Coal Refuse
Piles, Abandoned Mines and Outcrops, State of the Art. Washington,
D.C.: EPA 600/12-78-004v;1978.
Environmental Protection Agnecy, 1978b. Source Assessment:
Noncriteria Pollutant Emissions (1978 update). Industrial
Environmental Research Laboratory, Research Triangle Park, N.C.: EPA
600/2-78-004t;1978.
Environmental Protection Agency, 1978c. Needs Survey. Washington,
D.C.: Office of Water Planning and Standards, 1978.
Environmental Protection Agency, 1979a. Development Document for
Effluent Limitations Guidelines and Standards for the Ink Formulating
Point Source Category. Washington, D.C.: EPA 440/l-79/022-b;1979.
3-22
-------
Envirotunental Protection Agency, 1979c. Development Document for
Effluent Limitations Guidelines and Standards for the Gum and Wood
Chemicals Manufacturing Point Source Category. Washington, D.C.: EPA
440/l-79/078b;1979.
Environmental Protection Agency, 1979d. Development Document for
Effluent Limitations Guidelines and Standards for the Paint
Formulating Point Source Category. Washington, D.C.: EPA
440/l-79/049b;1979.
Environmental Protection Agency, 1979f. Development Document for
Effluent Limitations Guidelines and Standards for the Timber Products
Processing Point Source Category. Washington, D.C.: EPA
440/l-79/023b;1979.
Environmental Protection Agency, 1979g. Development Document for
Proposed Effluent Limitations Guidelines, New Source Performance
Standards and Pretreatment Standards for the Petroleum Refining Point
Source Category. Washington, D.C.: EPA 440/l-79/014b;1979.
Environmental Protection Agency, 1979h. Draft Development Document
for Proposed Effluent Limitations and Standards for the Iron and Steel
Manufacturing Point Source Category. Vol II. Cokemaking.
Washington, D.C.: EPA 440/l-79/024a;1979.
Environmental Protection Agency, 1979J. Comprehensive Sludge Study
Relevant to Section 8002(g) of the Resource Conservatio and Recovery
Act of 1976. Washington, D.C.: EPA SE-802;1979.
Environmental Protection Agency, 1979J . Environmental Impact
Statement Criteria for Classification of Solid Waste Disposal
Facilities and Practices. Washington, D.C.: SW-821;1979.
Environmental Protection Agency, 1980a. Priority Pollutant Frequency
Listing Tabulations and Descriptive Statistics. Memo from: Neptune,
D.; Analytical Programs to Schaffer, R.B.; Director of Effluent
Guidelines Divisions. Washington, D.C., 1980.
Environmental Protection Agency, 1980b. Contractor's Engineering
Report for the Development of Effluent Limitations Guidelines and
Standards for the Pharmaceutical Manufacturing Point Source Category.
Washington, D.C.: EPA 440/l-80/084a;1980.
Environmental Protection Agency, 1980c. Environmental Assessment Data
System. Research Triangle Park, N.C.: National Computing Center;
1980. Contact: Johnson, G.
3-23
-------
Environmental Protection Agency, 1980d. Human Exposure to Atmospheric
Concentrations of Selected Chemicals. A Summary of Data on Toluene.
Office of Air Quality Planning and Standards. Research Triangle Park,
N.C.: EPA Contract No. 68-02-3066;1980.
Environmental Protection Agency, 1980e. Fate of Priority Pollutants
in Publicly-Owned Treatment Works. Interim Report. Washington, D.C.:
EPA 400/1-80/301;1980.
Environmental Protection Agency, 1980f. Materials Balance for
Benzene, Level II. Washington, D.C.: EPA 560/13-80-009;1980.
General Tire and Rubber Co., inventor, assignee. Improvement in
pneumatic tyres and methods of making same. U.S. patent 737,086,
1955, Sept. 21. pp. 17.
Gleason, M.N.; Gosselin, R.E.; Hodge, H.C.; Smith, R.P. Clinical
Toxicology of Commercial Products. Acute Poisoning. 3rd ed.
Baltimore, MD.: Williams and Wilkins Co., 1968. pp. VI-1-132.
Green, A.D.; Morrell, C.E. Petroleum chemicals (In) Kirk-Othmer
Encyclopedia of Chemical Technology. 1st ed., N.Y.: John Wiley and
Sons. N.Y.: 10:177-210;1953.
Krinsky, L. (Bureau of Veterinary Medicine, U.S. Food and Drug
Administration) Personal Communication, 1980.
Lewis, P.F. Chlorinated Benzenes. Rockville, MD.: Department of
Health, Education and Welfare, Public Health Service, Division of
Chemical Technology;1975.
MacDonald, L.P.; Skinner, D.J.; Ropton, F.J.; Thomas, G.H. Burning
Waste Chlorinated Hydroacarbons in a Cement Kiln. Ottawa, Canada:
Environmental Protection Service, Fisheries and Environment; EPS
4-WP-77-2;1977.
O'Brochta, J.; Woolbridge, S.E. Coal-tar chemicals. Lowry, H.H. ed.
chemistry of coal utilization, Vol. II. N.Y.: John Wiley and Sons,
Inc., 1974. pp. 1325-1327.
Oil and Gas Journal, March, 1979.
3-24
-------
Rhodes, E.O. Tar and pitch (In) Kirk-Othmer Encyclopedia of Chemical
Technology. 1st ed. N.Y.: John Wiley and Sons. 13:614-632;1954.
South Coast Air Quality Manageaent District. Documentation of the
SCAQMD EIS modeling data base. El Monte, CA: KVB 22503-857;1979.
Stanford Research Institute, 1979. Chemical Econmics Handbook, Menlo
Park, CA, 1979.
U.S. Department of Agriculture. Tobacco situation: economics,
statistics and cooperative services. U.S. Department of Agriuclture,
1979.
U.S. Coast Guard (Pollution Incident Reporting System) Personal
Communication, 1980.
U.S. Department of Energy, Energy Data Reports: Energy Information
Administration. Coke and coal chemicals in 1978. Washington, D.C.,
1979.
U.S. Department of Interior, Bureau of Mines. Minerals Yearbook, Vol.
I: Metals, Minerals and Fuels. U.S. Government Printing Office Stock
NO. 024-004-01943-3;1976.
U.S. Department of Transportation (Materials Transportation Bureau.
Hazardous Material Incidents Reporting System) Personal
Communication, 1980.
U.S. International Trade Commission. Synthetic Organic Chemicals,
Production and Sales, 1978. Washington, D.C.: U.S. Government
Printing Office; 1979.
3-25
-------
4.0 FATE AND DISTRIBUTION OF TOLUENE IN THE ENVIRONMENT
4.1 INTRODUCTION
The following section describes the pathways of toluene into the
environment. The toluene releases from all known sources to the three
physical media (air, soil and water) are traced through the environment
co the human and biotic recepcors. First, data on the physical, chemical,
and biological characteristics of toluene are reviewed. The pathways and
processes that result in transfer of toluene from one medium to another
are analyzed. One method of doing this is a simple "partitioning" model,
supplemented by consideration of the relative rates of the transfer pro-
cesses. The next step is to evaluate major fate processes, such as
chemical transformation, that may occur in the media of interest in which
toluene is most likely to reside. The processes considered include chem-
ical transformation and biodegradation within the media of interest.
The loading rates, intermedia transfer processes, and intramedia
transformation/degradation processes are then used to estimate probable
ranges of concentration of toluene in the environmental media. This is
done by calculations involving "single compartment" models and by the
U.S. EPA's EXAMS (Exposure Analysis Modeling System) model. The final
step is to summarize the critical pathways, ranges of concentrations of
the pollutant in environmental media, and compare these with the available
monitoring data.
For toluene, the results of the materials balance analysis indicate
the estimated environmental releases are predominantly to the air (99% or
1,100,000 kkg), the remaining 0.2% is discharged to water or disposed of
on land.
The fate of toluene released to all three environmental media—air,
soil, water—is considered in the fate analysis in this section.
4.2 PHYSICAL. CHEMICAL. AND BIOLOGICAL CHARACTERISTICS OF TOLUEN'E
Toluene is an organic chemical whose physical and chemical charac-
teristics have been relatively well documented. Table 4-1 summarizes the
physico-chemical data that are directly relevant to the partitioning and
movement of toluene in the environment, and additional basic information
on properties of the bulk chemical that may be useful in evaluating fate
in particular situations (e.g., spills).
Toluene is moderately volatile as evidenced by the equilibrium
vapor pressure of 29 Torr at 25°C. However, the water solubility
(535 mg/1) indicates that aqueous media are also important. The low
values of the partition coefficients and bioconcentration factor in
Table 4-1 suggest that toluene is less likely to accumulate in soil,
sediment, or biotic environmental compartments that in air or water.
4-1
-------
TABLE 4-1. PHYSICAL-CHEMICAL PROPERTIES-OP TOLUENE
RELATED TO ENVIRONMENTAL DISTRIBUTION
Prooertv
Molecular Formula
Molecular Structure
Value
CH
Reference
Molecular Weight
Melting Point, °C
Boiling Point, °C
Density, g/ml
Water Solubility, mg/1
Vapor Pressure, Torr
Saturation Vapor
Concentration,
92.13 g
-95
110.6
0.8669 at 20°C
470 at 16°C
515 at 20°C
535 at 25°C
22 at 20*
29 at 259C
37 at 30°C
40 at 31.8°C
110 at 20 °C
184 at 30°C
Weast (1975)
Weast (1975)
Weast (1975)
Weast (1975)
Verschueren (1977)
Verschueren (1977)
Callahan e£ al. (19 79)
Verschueren (1977)
Callahan et. al. (1979)
Sax (1979)
Verschueren (1977)
Verschueren (1977)
Verschueren (1977)
Octanol: Water
Partition Coefficient
490
Callahan et al. (1979)
Organic Carbon
Partition Coefficient (Koc) 339 at 25°C
Bioconcentration Factor (Kp) 102 at 25°C
SRI (1980)
SRI (1980
4-2
-------
The toluene ring can be attacked by highly reactive species, such
as hydroxyl radical or ozone, which may be present in the environment.
Reaction with hydroxyl radical is an important environmental fate
process.
Biological degradation of toluene can be accomplished by both
individual species and mixed microbial populations isolated from various
environmental media. Biodegradation is indicated as a possibly impor-
tant intramedia fate process for both soil and water systems. Proper
conditions to support these processes must hold, however.
4.3 LEVELS MONITORED IN THE ENVIRONMENT
Monitoring data for concentrations of toluene in the environment
have been collected and analyzed for air and water; data relating to
concentrations in soil and biota are not as readily available. Lit-
erature reviews and the STORET Water Quality Information System were
the main sources of monitoring data for toluene. This section describes
specific monitoring data for toluene concentrations in various media.
4.3.1 Water Concentrations
This section presents monitoring data of toluene concentrations
in drinking and well waters, and ambient and effluent waters.
4.3.1.1 Drinking and Well Waters
In several U.S. EPA surveys of the nation's drinking water, toluene
has been detected in both raw and finished drinking supplies. Table 4-2
lists mean values and ranges of toluene concentrations in surface sup-
plies.
Data collected in ten U.S. cities showed that toluene was detected
in six of the ten supplies. Only two of the six cities where toluene was
detected had levels above the detection limit; these concentrations were
0.1 yg/1 (Cincinnati, OH); 0.7 yg/1 (Philadelphia, PA). The remaining
four, Tucson, AZ; Lawrence, MA; Grandforks, ND; and Terrebonne Parish, LA
showed a wide distribution of toluene across the country (U.S. EPA 1975)
(Table 4-2).
The National Organic Monitoring Survey (NOMS) was conducted in
three phases. During Phase I, however, toluene was not measured. Data
collected in Phases II and III do show concentrations of toluene in 1
of 111 and in 3 of 11 finished-water supplies, respectively. No quanti-
tative value of toluene was given for Phase II, and of the 3 finished
water samples in Phase III, only two actual concentrations were given:
0.5 and 19 y/1 (U.S. EPA 1978).
4-3
-------
TABLE 4-2. TOLUENE CONCENTRATIONS IN SURFACE SUPPLIES
OF DRINKING WATER
Location
or Mean
Study (ug/1)
Cincinnati, OH
Philadelphia, PA
Tucson, AZ
Lawrence, MA
Grand Forks, ND
Terrebonne Parish, LA
Waterford, NY 5.2
Niagara Falls, NY 0.22
New Orleans, LA
finished water
deionized, filtered
NOMS Data
Phase II Detected in 1/111
Phase III
City A
Citv B
City C
Cities D-K
CWSS Data
3 surface supplies 2.5
97 surface supplies
Tuscaloosa, AL
Washington, DC
Miami, FL
Ottumwa, IA
Evans vi lie, IN
Kansas City, KS
Johnson County, KS
New Orleans, LA
Range or
Observation
(us/1)
0.1
0.7
D
D
D
D
ND-19
0.005-0.6
1.51
3.00
supplies
D
'0.5
19
ND
<0. 5-6.1
ND
D
1.0
D
D
D
ND
ND
ND-0.1
Reference
U.S. EPA (1975)
U.S. EPA (1975)
U.S. EPA (1975)
U.S. EPA (1975)
U.S. EPA (1975)
U.S. EPA (1975)
Kim and Stone (1979)
Kim-and Stone (1979)
Dowty et^ al. (1975)
U.S. EPA (1978)
Brass (1981)
Brass (1981)
Bertsch e£ al. (1975)
Scheiman et al. (1974)
Coleman e_t al. (1976)
Coleman e£ al. (1976)
Kleopfer (1976)
Kleopfer (1976)
Kleopfer (1976)
Keith et al. (1976)
4-4
-------
TABLE 4-2. TOLUENE CONCENTRATIONS IN SURFACE SUPPLIES
OF DRINKING WATER (Continued)
Location
or
Study
Kirkwood, MO
Jefferson City, MO
Cincinnati, OH
Cincinnati, OH
Philadelphia, PA
Philadelphia, PA
Houston, TX
Seattle, WA
Mean
(ug/1)
Range or
Observation
(ug/1)
ND
D
0.1
D
D
0.7
D
D
Reference
Kleopfer (1976)
Kleopfer (1976)
Coleman et_ al. (1976)
Kopfler et al. (1975)
Suffett and Radziul (1975)
Coleman et al. (1976)
Bertsch et al. (1975)
Coleman et al. (1976)
• Mean value for surface supplies for data >_ D = 1.3 ug/1 (n=27),
assumes D • 0.1 ug/1, and using mean where given.
• Mean value of all data =0.15 (n=236)
assumes D = 0.1 ug/1 and ND = 0.
• Mean value of all data =• 0.24 (n-236)
assumes D • 0.1 ug/1 and ND • 0.1 ug/1
Notes;
D - Detected but not quantified.
ND = Not detected.
4-5
-------
The Community Water Supply Survey (CWSS) conducted by the U.S. EPA
tested 452 water utilities, representing 106 surface and 330 ground-
water supplies. There is concern over the possibility of false nega-
tives and underestimated concentrations due to a 1-2 year delay in
analysis. This is especially possible in the case of toluene, a
volatile, low molecular weight aromatic. Toluene was detected in 3
out of 100 surface water supplies with a median concentration of 0.85
and a mean of 2.5 ug/1 for positive values. It was detected in 2 out
of 307 groundwater supplies with measured concentrations of < 0.5 and
0.62 yg/1.
Dovty and coworkers (1975) examined the drinking water sources in
the New Orleans area for the occurrence and origin of aromatic and
halogenated aliphatic hydrocarbons. Three drinking water sources were
examined: (1) a New Orleans municipal water treatment facility before,
during, and after processing; (2) a commercial source of bottled arte-
sian water; and (3) a commercial source of deionized charcoal-filtered
finished water (Table 4-2). Relative concentrations at the treatment
facility were computed from gas chromatographic data. They show
toluene levels at 0.67 ug/1 in the Mississippi River water at the faci-
lity influent, 0.57 ug/1 in the clarifier effluent stage of treatment,
and 1.51 ug/1 in the finished water. The higher relative percent of
toluene in finished water appeared after the chlorination procedure.
Concentrations of 6.11 ug/1 were found in the commercially bottled
artesian water and 3.00 ug/1 in the commercial deionized charcoal-
filtered water.
In 1978, the New York State Department of Health and the United
States Geological Survey examined 39 wells for 112 organic chemical
contaminants in groundwater supplies (Table 4-3). Toluene was one of
the 10 most commonly found organic chemicals detected in 33 (or 85%) of
the wells tested. The maximum level of toluene detected was 10 ug/1
(Kim and Stone 1979). No other data were provided.
The Rim and Stone (1979) study also included data from an organic
contamination reconnaissance of 30 aquifers and found toluene in sam-
ples from 25. Concentration values for the individual contaminants
were not given; however, the sum of the concentrations of organic
contaminants was never >222 ug/1 in 8 samples, and a mean of 0.22 ug/1.
Eighty-seven percent of the observations recorded in STORET (U.S.
EPA 1980) for toluene in well water, which may be used for human con-
sumption, are less than the commonly-used detection limit of 5 ug/1.
Only 3 of the 143 observations recorded exceeded a concentration of
25 ug/1; these ranged from 42 to 100 ug/1-
4-6
-------
TABLE 4-3. TOLUENE CONCENTRATIONS IN GROUNDWATER
SUPPLIES OF DRINKING WATER
Location Range or Observation Reference
(yg/D
New Orleans
bottled artesian 6.11 Dowty et al. (1975)
New York State
33 wells Maximum = 10 Kim and Stone (1979)
6 wells ND Kim and Stone (1979)
25 aquifers Toluene Data not Separated Kim and Stone (1979)
5 aquifers ND Kim and Stone (1979)
STORET Wells \87%<5/ STORET (1980)
Maximum-^ 100 STORET (1980)
CWSS
Supply A <0.5 Brass (1981)
Supply B 0.62 Brass (1981)
305 Supplies ND Brass (1981)
Notes;
ND = Not Detected
4-7
-------
Obviously, the type of treatment affects the concentration of
toluene in finished drinking water. Using closed-loop stripping anal-
ysis (CLSA), Coleman e_t al_. (1976) evaluated the effect of granular
activated carbon (GAC) on the removal of organic contaminants from
drinking water. The documented results for twenty-five components of
the CLSA for GAC influents and effluents on the initial startup,
toluene was detected at 29 ng/1 in the influent and at 18 ng/1 in the
effluent, when approximately one million gallons of water passed
through the filter. After one month, with the same filter in place,
sampling indicated the presence of toluene in the influent at 10 ng/1
and in the effluent at 5 ng/1.
4.3.1.2 Ambient and Effluent Waters
The STORE! system appears to be the primary data base for infor-
mation regarding toluene in ambient and effluent waters. Table 4-4
exhibits a percentage distribution of all ambient and effluent concen-
trations of toluene for the major river basins and the United States.
Ambient Waters
The STORET (U.S. EPA 1980) monitoring data on ambient waters re-
flect sampling activities in 32 states, with results that show extremely
low concentrations. Of the 453 ambient concentrations recorded, 86 or
19% are unremarked values; of these, 48% is no higher than 10 ug/1 (78%
is no higher than 50 yg/1, and 86% no higher than 100 ug/1). Remarked
values (detection limits) range from 0 to 1000 yg/1 and unremarked values
ranged from 0 to 3900 ug/1. A detection limit of 0 is remarked as ma-
terial analyzed for but not detected. The most frequently used detec-
tion limits are 5 and 10 ug/1. Table 4-5 exhibits unremarked (above
the detection limit) monitoring data on toluene concentrations in 17
states.
Shelton and Kites (1978) identified nearly 100 compounds from
Delaware River water samples taken in 1976 and 1977. The particular
segment of river sampled is located amidst a heavily-industrialized
area (chemical manufacturing plants) and is a direct source of drinking
water for several cities in the Philadelphia metropolitan area. Toluene
was detected in the vapor stripping analysis of the October water sam-
ples; quantification was not possible, however. Toluene was not detected
in water samples collected during the winter and summer seasons.
Effluent Waters
STORET monitoring data for toluene in effluent waters reflect
sampling activities in 24 states. Of 510 recorded concentrations, the
majority of effluent concentrations recorded are remarked, 60%; the
most frequently used detection limits are 0.01, 1 and 5 ug/1*
4-8
-------
TABLE 4-4. PERCENTAGE DISTRIBUTION OK AMBIENT AND EFFLUENT TOLUENE CONCENTRATIONS
FOR MAJOR RIVER UASTNS AND THE UNITED STATES"
Concentration (\\R/1)
vo
Ha lor RJvcr Basin
Northeast
North Atlantic
Southeast
Tennessee River
Ohio River
Lake Erie
Upper Mississippi
Lake Michigan
Missouri River
Lower Mississippi
Colorado River
Western CulC
Pacific Northwest
California
Creut Basin
Puerto Kloo
UnlabcJ Ivil
UNITED STATES
Number of
Observations
1
14
110
16
54
2
18
30
34
8
3
IS
80
5
I
1
1
Ami) I un Lb
Percentage
jflO
100
93
81
98
fi7
20
44
88
100
100
99
100
LOO
100
100
10.1-]00
100
4
6
JOO
22
77
53
1
of Observations Number of
100.1-1000
4
6
2
11
3
3
13
>1000 Observations
103
48
100
6 28
70
64
6
16
1
1
45
Effluentc
Percentage
ilO
84
88
87
96
84
69
100
100
LOO
100
9L
10.1-100
9
6
10
4
11
30
7
of Observations
100.1-1000
4
6
3
3
2
2
>1000
3
I
393
14
482
85
11
Source: STOKET data (U.S. EPA 1980).
This compilation Includes both remarked and unremarked values. Remarked values are generally below
the detection limit. The detection limit is Included In the distribution. Some observations are
omitted during aggregation If station labeling information is Incomplete (e.g., no entry of latitude/
longitude for monitoring station).
407 ambient stations reporting.
''229 effluent stations reporting.
-------
TABLE 4-5. RANGES OF UNREMARKED VALUES OF AMBIENT TOLUENE CON-
CENTRATIONS FROM MONITORING DATA IN SEVENTEEN STATES
Number of
State Observations Range of Unremarked Values
(Ug/l)
Alabama 3 42 - 3900
California 12 0.1-1
Florida 1 13
Illinois 7 1-5
Indiana 1 2
Iowa 5 14 - 390
Kansas 3 28-46
Kentucky 1 285
Minnesota 2 1
Missouri 21 3 - 150
Nebraska 6 14 - 120
New Jersey 2 2-15
North Carolina 10 1 - 374
Pennsylvania 1 2
South Carolina 4 8 - 490
Tennessee 1 2
Washington 6_ 0.0 - 24
Overall 86 0.0 - 3900
Source: STORET data (U.S. EPA 1980).
4-10
-------
Jungclaus and coworkers (1978) analyzed wastewater, receiving
water, and sediments from a specialty chemicals manufacturing plant
for organic compounds. Wastewater and receiving water samples were
gathered from November 1975 to September 1976; sediment samples were
gathered from January 1976 to September 1976. Toluene was identified
in receiving waters through vapor stripping experiments only and could
not be quantified. In the industrial wastewaters, toluene concentra-
tions ranged from 13 to 20 ug/1, based on direct aqueous injection.
Toluene was not detected in sediment samples.
In 1979, Feller conducted a pilot study of two publicly owned
treatment works (POTWs) to characterize the impact of toxic pollutants
on POTW operations. Plant A handled more industrial wastewater than
Plant B, which reflected a lower incidence of organic pollutants than
the former. Toluene was detected in each of the 41 influent samples
analyzed at Plant A, and was detected in 95% of the 40 final effluent
samples analyzed. At Plant B, toluene was detected in 32, or 76%, of
the(42 influent samples and in 71% of the 41 final effluent samples.
Samples from the influent point of Plant A showed a maximum toluene
concentration of 440 ug/1 and median of 13 ug/1. At the influent point
of Plant B, the maximum toluene concentration was 37 ug/1 and the
median was 10 ug/1.
A survey of two municipal wastewater treatment plants for toxic
substances was conducted in the state of Ohio at Muddy Creek and at
Dayton (U.S. EPA 1977). The plant at Muddy Creek treated primarily
domestic wastewater; and the plant at Dayton combined industrial-
domestic influent. At the Muddy Creek plant, toluene concentrations
were measurable in 3 of the 15 influent samples taken. Levels ranged
from 1 to 5 ug/1. Toluene concentrations, measurable in 21% of the 14
final effluent samples, were 1 ug/1. At the more industrial treatment
plant of Dayton, toluene concentrations, measurable in 13 of the 15
influent samples, showed a range of 8-150 ug/1. In the final effluent,
toluene concentrations, measurable in 36% of the final effluent samples,
ranged from 1 to 10 ug/1.
As with ambient sampling data, 17 states show unremarked data from
monitoring of toluene (Table 4-6). The range of unremarked value was
observed to be ND to 4600 ug/1. Table 4-4 exhibits a percentage dis-
tribution of all effluent concentrations of toluene by major river
basin in the United States.
In 1977, Versar, Inc. calculated the gross annual discharges of
toluene to the nation's waters for 1976. The monitoring data obtained
from the U.S. EPA's Effluent Guidelines Division are presented in
Table 4-7. The concentrations of toluene in these effluents ranged
from 11 to 100,000 ug/1, although 9 of the 12 (75%) effluents reported
were <40 ug/1.
4-11
-------
TABLE 4-6. RANGES OF UNREMARKED VALUES OF EFFLUENT TOLUENE
CONCENTRATIONS FROM MONITORING DATA IN SEVENTEEN
STATES
Number of
State Observations Range of Unremarked Values
(Wg/l)
Alabama 1 18
Connecticut 14 0.8-3300
Florida 1 580
Georgia 26 1 - 140
Idaho ' 1 242
Illinois 7 0-2
Kansas 5 2 - 1050
Kentucky 3 1 - 4600
Maine 2 1 - - 39
Missouri 62 1 200
New Jersey 16 0.1 - 200
New York 25 0.2 - 1040
North Carolina 1 8
Ohio 26 1-101
Oregon 4 3-15
Virginia 3 3.5-46
Washington 8 0 - 20
Overall 205 0 - 4600
Source: STORET data (U.S. EPA 1930).
4-12
-------
TABLE 4-7. CONCENTRATIONS OF TOLUENE IN D1DUSTRIAL
EFFLUENTS
Number of
Plants in
Industry Mean Concentration5 1976
(Vg/l)
Wood Preserving • 1620 30
Wood Furniture Finishing 100,000 4000
Steam Electric Generating Station 405
Cooling Cycle Effluents 58
Ash Pond Effluens 35.5
Treatment Plant Effluents 22
TOTAL 115.5
Petroleum Refining 35
Coal Mining 11 5673
c b
Organic Chemical Mfg.
Textiles
Woven Fabric Dye Finish 13 187
Wool Dye Finish 12.5 28
Knit Fabric Dye Finish 19.2 69
Monferrous Metals
Primary Aluminum ' 32 31
Secondary Copper 34.6 12
aVersar Inc. (1977).
Calculated on the amount of product handled.
CData given as total waste amount per industry sector, not as effluent
concentrations.
4-13
-------
Analysis of toluene during wastewater treatment was performed by
Feiler (1980), while Levins et_ al^. (1980) considered, in detail, toluene
levels in wastewaters from various source-types for 4 cities. The
Feiler study included data for 20 cities on toluene concentrations in
influents, primary and secondary process effluents and sludges, and in
digested and combined sludges. These data are summarized in Table 4-8.
The data of Levins e£ al. (1980) indicate that wastewater toluene
levels may be equally high from both commercial and industrial sources
and these levels are 1-2 orders of magnitude above those found in re-
sidential wastewaters. The combined influent levels from both studies
cover the same range. Effluent levels tended to be below 1 ug/1 while
sludge concentrations were in the 10-27,000 ug/1 range.
4.3.1.3 Rainwater and Other Precipitation
None of the available literature reported the level of toluene
in rainwater, snow, or sleet.
4.3.2 Concentrations in Sediment
STORET data (U.S. EPA 1980) record less than 100 observations of
toluene concentrations in sediment. Of these observations, 91% had
toluene concentrations £ 10 ug/kg dry weight; 7% of the observations
were >500 ug/kg. The recorded concentrations reflect conditions for
nine states in the South and West: Texas, Louisiana, California,
Oregon, Washington, Idaho, New Mexico, Nevada, and Alabama. The
higher concentrations were observed in the vicinity of an industrial
area of San Francisco.
4.3.3 Concentrations in Foods
4.3.3.1 Fish Tissue
Sampling data for toluene in fish tissue are quite limited. At
present, only six states have fish tissue data maintained in the
STORET system. These states are: Oregon, Texas, Louisiana, Idaho,
Washington, Alaska, and California. Of the 59 observations, the
maximum concentration of toluene in fish tissue is 35 mg/kg wet weight
and the average concentration is 1 mg/kg. Ninety-five percent of the
samples are <1 mg/kg.
4.3.3.2 Other Foods
Toluene has been identified but not quantified in several nuts:
roasted filberts (Kinlin e_t al.. 1972), and peanuts and macadamia nuts
(Grain and Tang 1975, Walradt et. al. 1971). Stevens et. al. (1967)
found toluene in grape essence and Nursten and Sheen (1974) detected
toluene in cooked potatoes.
4-14
-------
TABLE 4-8. CONCENTRATIONS OF TOLUENE IN WASTEWATERS
AND SLUDGES FROM POTWs
Residential
Commerical
Industrial
Combined
Tap Water
Mean Values
2.6
11.0
52.3
25.6
0.3
Range of Means
for Each Citv
ND-11.9
1.1-27.6
5.4-123.8
1.9-60.2
ND-1.0
Reference
Levins et al. (1980)
Levins et al. (1980)
Levins et, al. (1980)
Levins et. al. (1980)
Levins et al. (1980)
Twenty-city Study
Combined Influents
Effluents
Primary Sludges
Secondary Sludges
Combined Sludges
Digested Sludges
Percent Removal
44.4
3.05a
1906
2566
3815
1230
90
4-229
ND-288
40-8810
3-14,652
54-26,857
124-2524
40-100
Feller (1980)
Feiler (1980)
Feiler (1980)
Feiler (1980)
Feiler (1980)
Feiler (1980)
Feiler (1980)
calculated assuming ND=0 and excluding the one effluent value that
exceeded the influent, also the only value in the hundreds of yg/1 range.
4-15
-------
4.3.4 Concentrations in the Atmosphere
Atmospheric toluene can occur as the result of contributions from
stationary sources (refineries, chemical plants, solvent users, and
gasoline marketing and distribution facilities), mobile sources
(vehicles), and localized sources (tobacco smoke). Vegetation has
been known to emit hydrocarbons, especially terpenes, but it is a
negligible source of toluene.
4.3.4.1 Contributions from Stationary and Mobile Sources
Toluene concentrations in the atmosphere of urban areas (including
areas with high chemical production), and rural and remote areas from
various studies beginning as early as 1963 are summarized in Table 4-9.
The urban areas with high chemical production had average toluene con-
centrations ranging from 0.19 to 59.52 iig/m3. Because of the concern
about motor vehicle emissions, Los Angeles is the most studied urban
area. Data on this city show toluene concentrations decreasing since
the 1963-65 period when Leonard et al. (1976) recorded concentrations
at 226 ug/m . In 1979, Singh e£ al. recorded an average toluene con-
centration of 45 ug/m3 in this city. This average concentration is
comparable with that of other urban areas. Similar concentrations of
toluene were recorded for both urban areas and areas with high chemical
production—33 vg/m3 in Phoenix, AZ, and 34 ug/m3 in Denver, CO. Atmos-
pheric toluene concentrations in rural and remote areas are generally
<1 yg/m3.
Sexton and Westburg (1980) monitored ambient air near an automobile
painting plant at Jamesville, WI, to investigate the effect of paint-
ing emissions on ambient ozone levels. From an individual hydro-
carbon identification analysis during fumigation by painting emissions,
the atmospheric toluene concentration within 1 mile of the plant was
601 ug/m . At three sampling stations (800 feet above the ground)
downwind of the automotive plant, toluene concentrations were measured
at 75.5 ug/m3 4 miles from the plant, 84.5 ug/m3 at 7 miles, 64.5 ug/m3
at 9 miles, and 55.5 ug/m3 at 11 miles. These concentrations range
from 10 to 15 times higher than the background toluene concentration of
5.5 ug/m approximately 1 mile northeast of the automotive plant.
Toluene was the most abundant aromatic hydrocarbon, constituting
35-40% of the total concentration of aromatics, when Lonneman et al.
(1968) conducted gas chromatographic analyses in Los Angeles in 1966
to relate aromatic hydrocarbon levels to atmospheric photochemical
reactivity. A total of 136 samples was collected in downtown Los An-
geles, Pasadena, Lennox, and West Los Angeles. The average concentration
of toluene was 0.14 mg/m3 and the maximum was 0.49 mg/in. The average
and maximum concentrations of the total aromatics were 0.41 mg/m3 and
1.26 mg/m3, respectively.
4-16
-------
TABLE 4-9. TOLUENE COMCENTRATIOSS IS THE ATMOSPHERE OF
URBAN, RURAL AND REMOTE AREAS
Location
URBAN AREAS
With High Chemical
Production
South Charles, WV
Birmingham, AL
Bacon Rouge, LA
Houston, TX
Magma, IT
Upland, CA
El Paso, TX
El Dorado, AK
Elizabeth, NJ
Average
Other Urban Areas
Phoenix, AZ
Oakland, CA
Los Angeles, CA
Denver, CO
Houston, TX
St. Louis, MO
Riverside, CA
Los Angeles, CA
(1963-65)
Los Angeles, CA (1971)
Los Angeles, CA (1973)
Los Angeles, CA -
Downtown (1967)
Los Angeles, CA -
Suburb (1967)
Denver, CO
Lake Charles, LA
Albany, NY
Troy, NY
Riverside, CA
Mean for all Urban Areas
(including data from
1977 on)
Concentrations (ug/m^)
Average Range
Reference
225.97
191.50
84.26
113
52.8
34.47
2.3
4.98
3.83
19
0.15 -
0.80 -
0.11 -
0.80 -
0.88 -
2.99 -
0.19 -
9.58 -
0.27
17.96
0.88
11.22
1.65
56.53
71.85
52.20
7.20 - 149.60
33.05
11.91
44.89
23.52
38.94
5.73
21.87
2.07 -
0.57 -
4.37 -
1.09 -
3.92 -
0.39 -
1.7 -
148.34
64.88
204.45
92.74
247.5
24.32
75.66
a
a
37 - 189
22 - 87
283.42 (max)
a
a
a
34.47-68.94
Pellizzarl
Pellizzari
Pellizzari
Pellizzari
Pellizzari
Pellizzari
Pellizzari
Pellizzari
Pellizzari
(1979)
(1979)
(1979)
(1979)
(1979)
(1979)
(1979)
(1979)
(1979)
Singh st_ al.
Singh et_ al.
Singh et_ al.
Singh et_ al.
Singh et^ al.
Singh e_t_ al.
Singh e£ al.
(1979)
(1979)
(1979)
(1980)
(1980)
(19SO)
(1980)
Leonard et al. (1976)
Leonard et al. (1976)
Leonard e_t_ al. (1976)
Altshuller et al. (1971)
Altshuller et. al. (1971)
Russel (1977)
Harden e_^ al.
Altwicker et al. (1977)
Altwicker et_ al. (1977)
Stephens (1973)
4-17
-------
TABLE It-1). TOLUENE CONCENTRATIONS IN Till;: ATMOSPHERE OF
URBAN, RUKAL AND REMOTE AREAS (Continued)
Concentrations
GO
Location
RURAL AND REMOTE AREAS
Grand Canyon, AZ
Camel's Hump, VT
Hell's Canyon, ID
Moscow Mt., ID
Point Reyes, CA
Brethway-Gunderson
Hill, WA
Remote Air Masses'1
Gabriel Mts., CA
Average
Trace
3.71
1.13
0.75
0.75
0.38
ND
Trace
a
a
a
a
a
0.2-57.45
Reference
Pelllzzari (1979)
Robinson et al. (1973)
Robinson et al. (1973)
Robinson et al. (1973)
Robinson et al. (1973)
Robinson et al. (1973)
Robinson et al. (]973)
Stephens (1973)
Mean for Rural Areas0
1.0
Information not supplied.
Tropical, polar, and equatorial air masses, including pacific coast, and
pacific and Atlantic inland masses.
°Assumed ND=0, Trace-0.1 |ig/«|3 and excluded remote air masses.
-------
Filar and Graydon (1973) observed concentration variations related
to automobile traffic by sampling simultaneously several locations in
the urban Toronto area. The overall average concentration of toluene
was calculated as 115 ug/m3, the maximum concentration was 720 yg/m in
Toronto, Canada. The times of maximum toluene concentration in down-
town Toronto were similar to those found in Chicago and Los Angeles
around 7:00 a.a., 3:00 p.m., and 9:00 p.m. In Toronto's Centre Island,
where only official vehicles are allowed, concentrations of toluene
were consistently lower. The air concentration ratio averaged to 2.6
for toluene when site data from the island and downtown Toronto were
compared. One notable result of the Filar and Graydon (1973) study
was that the ratio of benzene to toluene was less in the atmosphere than
in motor vehicle exhausts. The authors suggested that "the relatively
high toluene:benzene ratio in gasoline vapor points to the possibility
of direct evaporation of gasoline as a source."
In 1961, Altshuller and Bellar (1963), demonstrated that rapid
repetitive analysis of small volume samples taken from polluted atmos-
pheres are possible with gas chromatographs containing flame ionization
detectors. Experiments in the downtown Los Angeles area showed that
only a small fraction of the hydrocarbons present in the atmosphere are
highly reactive in producing smog manifestations. Toluene concentrations
.ranged from 0.10 to 0.23 mg/m , with an average concentration of 0.17 mg/
In a later study, Altschuller et^ al. (1971) showed that atmospheric
concentrations of toluene (along with other hydrocarbons) are largely
associated with motor vehicle emissions. Variations in ratios through-
out the day were considered consistent with the difference in rates of
reactions of these individual hydrocarbons. This study compared a
suburb of Los Angeles with the downtown area and determined extrapolated
peaks of about 77 and ISO ug/m^ in the diurnal curves, respectively.
The nighttime levels in the suburb were between 45 and 50 ug/m^, while
in the downtown area, they were about 75 to 85 ug/m . The overall aver-
age values were 113 yg/m^ for downtown and 52.8 yg/nr for the suburban
area. The levels exceeded by 10% of the values were 189 and 36.7 ug/nr
for the downtown area and the suburban area, respectively.
4.3.4.2 Contributions by Vegetation
Volatile hydrocarbons are sometimes emitted by vegetation in sig-
nificant amounts; the alkyl benzenes are often minor constituents of
such emissions. Toluene, however, is emitted predominantly by a
tropical tree, the tolu, from which it gets its name, and therefore
significant amounts are not produced in the United States (NRC 1980).
4-19
-------
4.3.4.3 Contributions from Cigarettes
Measurements by several researchers cited in NRC (1980) indicated
that the alkyl benzenes included in cigarette smoke occurred only in the
smoke as combusion products, and were not found in the tobacco itself.
The range of observations of the net yield of toluene from one cigarette
was 46-164 yg (Johnstone e_t al_. 1962, Grob 1965). The NRC calculated
that if 0.1 mg toluene is the net yield from one cigarette that the smoke
would contain about 11,300 yg/m .and that "smoke filled rooms" could
contain between 230 to 2300 ug/m . These values are considerably
higher than levels measured in urban areas as shown in Table 4-9.
4.4 ENVIRONMENTAL FATE MODELING AND ANALYSIS
4.4.1 EXAMS Modeling
The U.S. EPA's Exposure Analysis Modeling System (EXAMS) prograss is
one approach to the integration of various intermedia transfer and in-
traaiedium transformation processes. The EXAMS model considers physical
constants and reaction rate data for the chemical and the characteristics
of various aquatic environments.
The environmental fate of toluene was modeled using four EXAMS
scenarios: "clean" river, turbid river, oligotrophic lake, and a
eutrophic lake. Toluene loading rates were selected as inputs to EXAMS.
The highest was 1.0 kg/hr based on a maximum effluent level measured for
toluene at a POTW. The second rate, 0.023 kg/hr, was representative of
median toluene concentrations for 20 POTWs. The third loading rate, 0.04
kg/hr, is based on discharges from 62% of the pharmaceutical plants using
toluene. Fate in all the scenarios were considered for all the rates.
(The results will scale directly with the loading rate until/unless the
water solubility is exceeded or some other environmental compartment
saturates.) The fundamental difference between the river and lake
scenarios is that the former are flowing systems so that downstream
transport/dispersal appears as a major fate process. The turbid river
has a fivefold higher level of suspended sediment than the "clean" river.
The eutrophic lake differs from the oligotrophic lake in that it
has much higher (three orders of magnitude) bacterial populations, a
higher organic carbon content of the sediment, as well as somewhat
higher levels of suspended sediment.
The summary of results from running the EXAMS model is presented in
Table 4-10. In the river systems, downstream export appears as the
dominant fate process, carrying away >99% of the load. Volatilization
is a less significant transport process, accounting for a loss of <1%
of the load within the ^54-minute residence time of the river "slice".
In the oligotrophic lake system, the relative importance of export and
volatilization is reversed; volatilization accounts for 90% of the
removal and export for approximately 10%. In the eutrophic lake system,
4-20
-------
volatilization is also more important than export (95% versus 0.2% of
load). In this lake, however, EXAMS indicates that biodegradation may
account for up to ^5% of the losses. In the river, removal will be
determined primarily by physical processes, with waterborne export and
volatilization the dominant removal processes. For these four scenarios,
chemical transformation plays only a minor role (0.02-0.11%) in the mass
balance of the lake and pond systems only.
For each of the four ecosystems, the EXAMS-calculated partitioning
between water and sediments estimated that >94% of the toluene would
be in the water column and <6% in the bottom sediments.
The water column concentrations predicted by EXAMS are <1 yg/1 for
all scenarios and discharge rates, with the exception of the pharmaceu-
tical discharge to oligotrophic lake scenario, which resulted in con-
centrations of up to 5 ug/1.
For both river scenarios used in the EXAMS model, the current
velocity is 0.93 m/sec, the depth of the water column is 3 meters, the
width and length of the river segment are 10Q and 3000 meters, respec-
tively, and the water flow rate is 2.41 x 10' or/day. In both turbid
and clean rivers, over 99% of the toluene in the original flux into
the river segment analyzed is passed onto the next segment, and <1«
volatilizes or is biodegraded. The physical representation of an EXAMS
river allows the use of an exponential decay function to solve for the
number of river segments through which the toluene load must flow until
some percentage (i.e., 99%) of the load either leaves the water compart-
ment by biodegradation or volatilization.
The calculation is:
(mass flux % to next river segment)11 = 0.01
where n_ is the number of segments necessary to obtain a 99%-reduction
in the initial loading of toluene to the river. Solving:
n log (0.952) = log 0.01
n = 93.62
Because each EXAMS river segment is 3000 meters long, this distance
is about 230,000 meters (170 miles); with a water velocity of 0.93 m/sec,
about 3.5 days are necessary for this 99%-reduction to occur given the
dimensions used for the EXAMS river. Similar calculations show that a
reduction of 50% of the initial load occurs in 13 hours over a river
stretch of about 42,000 meters (26 miles).
4-21
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TABLE 4-10 RESULTS OF EXAMS MODELING OF THE ENVIRONMENTAL
FATE OF TOLUENE DISCHARGE SCENARIOS
Compartment
Sottorn Sediments
Water Column
Fate Process
Waterbome Export
Volatilized
Biodegraded
Chemically Transforaed
Rivers'
Lakes
Clean Turbid Oligotroohic Eutroohic
Percent in compartment in Steady State
1.82 5.23 6-08 2.24
98.18 94.77 93.92 97.76
Percent removed by fate process at Steady State
99.46 99.86 10.04 0.19
0.18 0.05 89.57 94.97
0.36 0.09 0.31 4.81
0 0 0.08 0.02
Column Concentrations (u?/l) for Discharge Scenarios
1. POTO-maximum observed effluent concentration of 288 ug/1. At flow of 87 x
T65~l/day (23 MGD) the loading rate is 1 kg/hr.
0.12
0.03
2. POTW~median observed effluent concentration for 20 POTW of 1 yg/1. At high
flow" of 550 x 106 I/day (150 MGD) the loading rate is 0.023 kg/hr.
0.003
0.0007
3. Pharmaceuticals Industry-load of 24 kkg/hr for 250 Plants. Based on 62%
occurence in effluents, 250 of 400 plants had a loading rate of 0.04 kg/hr.
0.005
0.001
4.6
0.86
aRiver volume flow rate = 300 m3/sec.
bSee Table 3-1 in Materials Balance for data.
cSee Table 3-5 in Materials Balance for data, also personal communication,
Acurex (1980).
4-22
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4.4.2 Intermedia Transfers
4.4.2.1 From Air Medium to Surface Waters or Land
Based on the materials balance analysis, air is the dominant
receiving medium for toluene emissions. Furthermore, the vapor pressure
of toluene is sufficiently high (see Table 4-1) so that this chemical
will have a strong tendency to remain in the atmosphere as a vapor.
Dry deposition is not a plausible removal process for atmospheric
toluene vapors because the vapor pressure of toluene is too high to
attach to aerosols (Jungclaus 1978).
Toluene residing in the air is not transported to the surface by
dry deposition or by precipitation. Atmospheric oxidation of toluene
removes 50% of the compound in less than 2 days (see Section 4.4.3.1).
Because of this rapid removal rate, toluene will most likely not remain
in the atmosphere long enough to be removed by air to surface transfer
mechanisms.
4.4.2.2 Water
Water to Air
Volatilization is an important process in the depletion of toluene
from water. A model was used to determine the volatilization half-life
of toluene in water (a 1-meter deep stream with a velocity of 1 m/sec).
The half-life was 5 hours corresponding to a distance of ^18 kilometers
downstream from the discharge. To remove 90% of the discharged toluene
requires *->15 hours and a distance of over 50 kilometers. These calcu-
lations are described in Appendix E.
Water to Sediment
As shown by the EXAMS model, some toluene partitions to the sedi-
ment compartment (2-6%). The log octanol-water partition coefficient
(2.69) shows that toluene has some affinity to bind to the sediment.
However, the extent to which toluene is transferred depends on the
sorption capability of the particular sediment, which, in turn, depends
on the organic carbon content and other characteristics.
4.4.2.3 Soil
Soil to Air
Wilson et_ al. (1980) conducted laboratory experiments on the vola-
tilization of toluene from soil. These experiments indicated that, in
a sandy soil system, on the order of 40-60% of toluene applied to the
surface will volatilize.
4-23
-------
Volatilization characteristics from soil surfaces low in adsorbing
materials are expected to be similar. In the case of municipal sludges,
volatilization may be significantly retarded because of the sorption
propensity of toluene for this highly organic material.
No volatilization rate measurements for soil to air were found in
the literature. However, using the Dow method described by Thomas
(1981) a half-life for volatilization from soil of about 9 seconds was
estimated. This half-life applies only to toluene applied to the
surface, and suggests that volatilization will be rapid in such a
situation. Volatilization of toluene mixed with the soil is highly
dependent on the soil type, but the half-life would probably be slower
than 5 hours which was calculated for volatilization from water in a
river system.
Soil to Water
The amount of toluene that will be available to migrate from the
soil medium to water will be determined by (1) extent of biodegradation,
(2) organic content of the soil and (3) flushing action of either run-
off water or groundwater recharge. Laboratory tests by Wilson et al.
(1980) showed that in sandy soil (low organic content) and without bio-
degradation, toluene leached easily. This indicates that in certain
soils, toluene may reach the groundwater, where it is unlikely to degrade,
4.4.3 Intramedia Fate Processes
4.4.3.1 Air
As shown in the materials balance section of this report, known
environmental releases of toluene, in 1978, were approximately 10% x
10-3 kkg. Of this amount, it was estimated that 99.72 was released
directly into the atmosphere. The atmosphere is the major receiving
media for toluene emissions; therefore, the chemical reactions that
deplete toluene from the atmosphere have great importance in the
overall environmental fate of toluene.
Oxidation
Several free radicals combine with compounds to promote the break-
down and eventual removal of these compounds from the atmosphere.
Hydroxyl radicals (OH), atomic oxygen (0), peroxy radical (R02, where R
is an alkyl or acyl group) and ozone (Oo) are most likely to combine
with toluene. According to Hendry (1979) the reaction of OH" is the
4-24
-------
most important reaction involving the free radicals in the removal of
toluene from the atmosphere. This conclusion is based on two factors:
(1) the rate of reaction of the free radical with toluene, and (2) the
atmospheric concentration of the free radical in question. Note that
the OH~ concentration is a function of the temperature and chemical
composition of the atmosphere (especially with regard to other pollutants)
and, most strongly, the solar intensity. During the evening hours, the
OH~ concentration decreases sharply, slowing down the atmospheric re-
moval of toluene processes (NRC 1980). However, during daylight hours,
the concentration of OH~ is at its peak. Estimates of toluene break-
down because of OH" attack will be based on daylight concentrations
obtained from experimental data.
Photochemistry
The addition of the hydroxyl radical to the aromatic ring or the
abstraction of the hydrogen from the methyl side chain (Figure 4-1)
can lead to the reaction of OH with toluene. Several studies have
investigated the relative importance of these two reactions and have
found a greater likelihood of the addition process occurring than the
abstraction process.
Davis and ccworkers (1979) measured the reaction rate constant of
toluene at 298°K in a toluene helium gas mixture while varying the
pressure of the helium gas. They observed that the reaction rate
constant varied with pressure such that the rate constant increased
by a factor of two as the pressure increased from 3 to 100 torr.
According to the authors, only the addition reaction would show a •
pressure dependency. It was concluded that at least 50% of the total
reaction resulted from the addition of OH" to the ring. Because the
carbon hydrogen bond is weak, the hydrogen can readily be abstracted by
the OH radical. Nevertheless this latter mechanism was assessed as
less important.
In another study, Kenley et al. (1973) examined the relative im-
portance of the two mechanisms by direct measurement of the products.
They assessed the rates of atmospheric reaction and proposed that it
would yield 85% cresol isomers and 15% benzaldehyde; thus, they demon-
strated that the addition mechanism is likely to be of greater signif-
icance. In addition to benzaldehyde and cresol, Kenley et al. (1978)
identified nitrotoluene as a product of the OH~ toluene reactions with
yields <1% of the total. However, Hoshino et al. (1978) pointed out
that the quantity of m-nitrotoluene is directly proportional to the
initial concentration of N02.
4-25
-------
Finally, O'Brien and coworkers (1979) studied the products of the
OH radical attack under simulated atmospheric conditions. They also
found that the reaction yields cresol and benzaldehyde, although the
actual percentages were smaller than those reported by Kenley e_t al.
(1978). Hoshino and coworkers (1978) also found that cresol and
benzaldehyde were the major products, with yields at a ratio of
roughly 2:1.
Recently, it has been shown that toluene oxidation can lead to
the production of peroxyacetylnitrate (FAN) and peroxybenzoylnitrate
(PBzN) (Altshuller e£ al. 1971, Heuss and Glasson 1968, Spicer and
Jones 1977, Dimitriades and Wesson 1972). PAN is either produced by
the fragmentation of the aromatic ring immediately following the reaction
of OH~ and toluene or by the secondary reactions involving products of
the OH" toluene reaction. The photo-oxidation of benzaldehyde, which
was demonstrated earlier as a prominent by-product of the reaction of
OH radicals with toluene, forms PBzN.
The rate of toluene removal as the result of the toluene reaction
with the free radicals PAN and PBzN is summarized in Table 4-11. The
concentration of the hydroxyl concentration is based on experimental
data at solar intensities that vary according to latitude and season.
Table 4-11 demonstrates that the rate of removal as a result of OH
radical attack exceeds the rate of removal by the remaining free
radicals by a factor of 102 - 107.
To determine the half-life of toluene in the atmosphere, the pro-
duct of the rate constant must be added to the average radical concen-
tration over all the free radicals so that the total rate constant
as a result of oxidation, KQX, is:
Kgx D ^OH l^^J "*" ^o i • "*" ^03 '3J "*" RO?
- 1.5 x 10"5 sec"1.
Based on this rate, the half-life of toluene in the atmosphere
as a result of oxidation is 13 hours. This value was determined using
an average value for the concentration of OH radicals. Depending upon
the actual OH concentration, the half-life of toluene may range from 11
to 52 hours. Therefore, two days is a reasonable upper limit value for
the half-life of toluene in the atmosphere.
4-26
-------
CH,
CH.
CH,
OH+
Radical
Addition
OH
OH
(1)
Toluene
CH.
1: Addition Process
Cresol
OH+
Radical
Abstraaion
CH202
(2)
Benzyl Peroxy Radical Benzoxy Radical
2: Abstraction Process
Benzaldehyde
FIGURE 4-1 REACTION OF HYDROXYL RADICALS WITH TOLUENE
4-27
-------
TABLE 4-11. RATE OF ATMOSPHERIC OXIDATION OF TOLUENE BP
FREE RADICALS3
Radical
Hydroxyl
Radical
Atomic
Oxygen
Ozone
Peroxy
Radicals
Estimated Average
Daylight Concentration
(molecules/cm^)
Rate Constant
(cm3/molecule-sec)
0.75 x 106 - 0.37 x 107 6.4 x 10'12
0.75 x 105
0.75 x 1010
0.25 x 108
7.4 x 10-12
3.4 x 10"22
1.7 x 10"22
Rate of Toluene
Removal
(sec"1)
2.4 x ID-5
4.8 x 10~6
5.6 x 10-7
2.6 x KT12
4.3 x lO'15
aAdapted from NRC 1980.
Crutzen and Fishaan (1977).
4-28
-------
Direct Photolysis
Photolytic reduction of toluene is not a direct cause of toluene
removal because toluene does not adsorb light wavelenghts >286 nm.
However, a charge-transfer complex between toluene and molecular
oxygen will permit radiation adsorption to light wavelengths of at
least 350 nm. Wei and Adelman (1969) note that the photolysis of
this complex results in the observed oxidation products of benzyl
alcohol and benzaldehyde. Additional evidence of photolytic interven-
tion in oxidation has not been cited, nor has substantial evidence
been found concerning other possible mechanisms of toluene photolysis.
This suggests that photolysis is not an important process in the
removal of toluene from the atmosphere.
Dispersion
The toluene emission sources referred to in the section on materials
balance indicate that many chemical plants using or synthesizing toluene
emit 15-25 kkg/yr and that 50 kkg/yr is a representative maximum toluene
release, while 20 kkg is a good figure for the average plant. Downwind
air concentrations of plants releasing these amounts were calculated
using a Gaussian plume dispersion model (Appendix F). The results are
based on the assumption that the stack was 'elevated, and that no
chemical degradation occurred simultaneously in the plume.
Ground level concentrations based on the Gaussian plume dispersion
model are shown in Table 4-12 for various downwind distances from the
sources. These concentrations are respresentative; weather, emission
rate fluctuations, and location within the dispersing plume will cause
actual levels to vary. Concentrations are generally <0.1 ug/nr at
distances >500 meters from the source. For the plant releasing an
average amount of toluene (20 kkg/yr), at 100 meters, the concentration
is 0.5 ug/m^. At 100 meters, the larger source could generate a concen-
tration of 1.2 ug/rn^. These levels are an order of magnitude less than
the mean concentration found for urban air in Section 4.3.4.
4.4.3.2 Water
Oxidation
The reaction of toluene in water with OH radicals formed from the
irradiation of hydrogen peroxide has been shown to produce benzaldehyde,
benzyl alcohol, and cresol isomers (Jefcoate et al. 1969). These are
the same products formed by atmospheric oxidation. Molecular oxygen
may also oxidize liquid toluene, however, the presence of water will
inhibit this oxidation (Stephens and Roduta 1935). Thus, molecular
oxygen can be eliminated as a possible mode of toluene removal from
the aqueous environment. No rates for this process have been found;
therefore, this process is not assumed significant.
4-29
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TABLE 4-12. TOLUENE CONCENTRATIONS IN AIR DOWNWIND DISTANCES
OF CHEMICAL PLANTS USING TOLUENE
Ground Level Concentration in Air (ng/aH)
Distance (meters)
Emission Rate 100 500 1000 1500 5000 10,000
20 kkg/yr
Q - 6.34 x 10~4 kg/sec 480 60 20 10 1.5 0.5
50 kkg/yr
Q = 1.6 x lO'3 kg/sec 1200 150 50 25
_
Ground Level Concentration = ff exP 2a2
u,, • wind speed » 5 m/sec
Neutral Atmospheric Stability Class D
Non-buoyant Source, 10 meters high
See text and Appendix F for details concerning the estimation
methods .
4-30
-------
Hydrolysis
Although there is not direct data on toluene hydrolysis, some
authors have concluded that this is not a significant fate process.
"The covalent bond of a substituent attached to an aromatic ring is
usually resistant to hydrolysis because of the high negative charge-
density of the aromatic nucleus" (Callahan et al. 1979).
Chlorination
During wastewater treatment with chlorine, some compounds will
react with chlorine to form toxic or persistent compounds. With tol-
uene, this is not the case. In laboratory tests conducted by the
Chemical Manufacturers Association for the U.S. EPA (1972), 10 mg/1 of
toluene was combined with 5, 10, and 20 mg/1 of chlorine in a 500 nil
sample. The mixture was rotated at 80 rpm, 25°C. Samples examined
after 0.5, 1.0, 2.0, and 24.0 hours revealed, in all cases, that the
quantity of chlorine absorbed by toluene was <4% of the chlorine dosage.
Carlson and Caple (1975) also carried out reaction measurements, demon-
strating that chlorine did not bind with toluene. When a 9.5 x 10~4
solution of toluene was mixed with a 7 x lO'^M solution of chlorine
at 25°C for 20 minutes, 11% of the chlorine was absorbed at pH3,
while only 2.8% was absorbed under neutral conditions.
4.4.3.3 Soil
Sorption
The octanol:water partition coefficient (Kowj.=490) and the organic
carbon partition coefficient (^+=339) for toluene indicate that it
has some affinity to bind with organic components in the soil. Because
of variations in the organic content of soils, however, generalizations
cannot be made concerning the sorption of toluene in soils. In addition,
the concentration of toluene in POTW sludge indicates that adsorption
could be significant in soils with high organic content (Personal com-
munication, Moss, U.S. EPA 1980).
Biodegradation
Biodegradation of toluene in soil can be an important process.
Claus and Walker (1964) have measured the degradation half-life of
toluene of 20-60 minutes in soil inhabited by certain bacterial species,
which proved capable of utilizing toluene as a sole carbon source. The
authors suggest that the biodegradation route of toluene is:
Toluene * 3 Methylcatechol •* acetic acid, pyruvic acid, ether
fractions
4-31
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Wilson (1980) indicated that from 20 to 60% of toluene eluted through
a 140-centimeter of sandy soil biodegraded. The process is probably
highly sensitive to the soil type; therefore, for a particular soil
system, it may be an important removal process of toluene. However,
Chambers and coworkers (1963) found that although "toluene was oxidized
to a limited extent . . . that in general they (benzene derivatives)
were resistant to degradation" by phenol-adapted bacteria. Therefore,
environmental conditions must be conducive to biodegradation of toluene
in the soil by the appropriate bacterial populations.
Chemical Transformations
Chemical transformations in soil as a result of oxidation, hydro-
lysis, or other chemical (nonbiological) processes are not indicated.
4.4.3.4 Biota
Little definitive data are available on the fate of toluene in
aquatic organisms, however, some qualitative observations have been
made. Toluene was absorbed rapidly from water into the Pacific herring
(Clupea harengus pallasi) with maximum levels reached in 24 hours. In
their gallbladders, which contained the highest residues (34 mg/kg),
toluene reached a concentration 340 times greater than that measured
in the water (0.1 mg/1) (Korn e£ al. 1977). All detectable toluene
was depurated in several days after transfer to fresh water.
Eels (Anguilla japonica) reared in seawater containing crude oil
accumulated toluene to a concentration ratio (eel:freshwater) of 13:2.
The half-life of toluene was 1.4 days after transfer to clean seawater
(NRC 1980). Toluene was tekan up (3-10 ug/1) through the gill tissues
of the mussel Mytilus edulis; it was subsequently transferred to the
mantle, adductor muscle, and the guts. No evidence of metabolism was
demonstrated. When transferred to fresh seawater, the mussels depurated
most of the toluene from their tissues (Buikema and Hendricks 1980).
A comparative study was conducted of toluene bioconcentration in
various organs of freshwater crayfish (0. rusticus) and bluegill sunfish
(Lepomis macrochirus). All tissues in both species accumulated toluene
to at least a factor of 2, with the greatest tissue concentration factor,
^140, seen in the hepatopancreas of the crayfish. This organ contains
large amounts of lipids. Because toluene is lipid-soluble, the hepato-
pancreas is the most likely organ to accumulate toluene concentrations.
Figures 4-2 and 4-3 illustrate the significant differences in both
the rate and degree of bioaccumulation (here given as the tissue con-
centration factor) of toluene in these two species. The author hypo-
thesized that bluegills are able to metabolize toluene and store the
metabolites, whereas crayfish are not; this may, in part, account for
the observation that bluegills were ten times more sensitive than cray-
fish to toluene (Berry 1977).
4-32
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50 r
0 1 2
8
12 16
Time (hrs)
Note: Each point is the mean TCF of two to four organs.
20
24
48
S - Spleen
T - Testes
GB - Gall Bladder
Gt —Gut
H -Heart
G - Gill
K - Kidney
L - Liver
B — Brain
0 - Ovary
FIGURE 4-2 TISSUE CONCENTRATION FACTORS (TCF) FOR TOLUENE IN VARIOUS
BLUEGILL SUNFISH ORGANS AT GIVEN TIMES OF EXPOSURE
4-33
-------
150
140
110
100
90
80
.2 70
a
I
j 60
2
50
40
30
20
10
HP - Hepatopancreas
H -Heart
GG-Green Gland
0 -Ovary
G -Gill
Gt - Gut
T -Testes
M -Muscle
012 4
8
20
24
12 16
Time (hrs)
Note: Each point is the mean TCF of two to four organs.
FIGURE 4-3 TISSUE CONCENTRATION FACTORS (TCF) FOR TOLUENE IN
VARIOUS CRAYFISH ORGANS AT GIVEN TIMES OF EXPOSURE
48
4-34
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In another study (Berry and Fisher 1979) mosquito larvae that had
taken up ^C-labeled toluene were fed to bluegill sunfish (Lepomis
macrochirus). Toluene did concentrate in the stomach and intestine;
however, most of the toluene was contained within the digestive tract
and did not accumulate in other vital organs. One conclusion of this
study was that bioaccumulation of chemicals within aquatic food chains
is insignificant when compared with accumulation directly from water.
No measured steady state bioconcentration factor (8CF) is available
for toluene; however, based on the octanol:water partition coefficient,
it has been estimated to be 70 (U.S. EPA 1979). A BCF of 120 (25°C)
has been reported by SRI (1980). Thus, because of the low bioconcen-
tration potential, rapid depuration, and the ability of fish to metab-
olize toluene, it is unlikely that bioconcentration and biomagnification
of toluene through food chains will be a significant problem in aquatic
systems.
4.5 SUMMARY
This chapter has described the environmental fate of toluene from
the perspective of the three major environmental compartments. The
processes that may transfer toluene from one to the other have been
analyzed for their significance and reaction rates. The processes that
have the potential to alter chemically or degrade toluene within a given
compartment have been similarly considered.
The major fate processes, both inter- and intra-medium, are shown
in Figure 4-4 and summarized below.
4.5.1 Intermedium Transfer Processes
4.5.1.1 Air
• Rainout to Water and Land. A reaction limited by the short
residence time of toluene in the atmosphere.
Conclusion. Negligible overall importance.
4.5.1.2 Water
• Volatilization to Air. Occurs quite quickly; controlled
by diffusion within water bodies; however, this usually
is not limiting.
Conclusion. A major pathway.
• Adsorption to Sediments. Occurs on a limited basis; highly
dependent on soil type, i.e., organic content, relative
concentrations, etc.
Conclusion. Limited overall importance.
4-35
-------
Biota
Biomagnif ication and
Bioconcantration
(minimal)
Air
Oxidation Destruction
(Very Fast)
01
3
o
Water
small losses
from Biodegradation
8
I
i
_
I
a
-------
4.5.1.3 Soil
• Volatilization to Air. Occurs quite quickly; controlled
by soil type and conditions.
Conclusion. A major pathway.
• Solution into Water. Soil toluene may dissolve in soil
water as determined by its solubility and the amount of
water present.
Conclusion. Possibly significant.
• Runoff to Water. Surficial toluene would be preferentially
volatilized. Any toluene bound to surface particles could
be carried off physically, and some would be carried in
solution.
Conclusion. Possibly significant.
4.5.2 Intranedium Fate Processes
4.5.2.1 Air
• Oxidation by Hydroxvl Radicals. A fast reaction, determined
by concentrations of OH.
Conclusion. Dominant fate process — responsible for
destruction of most environmental toluene.
4.5.2.2 Water
• Degradation by Microbial Species. Requires the presence
of appropriate species.
Conclusion. Important in some habitats, but not universally
important.
4.5.2.3 Soil
• Biodegradation. Requires the presence of appropriate species.
Conclusion. Important in some soil situations, but not
universally important.
4-37
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4.5.3 Critical Pathways for Specific Sources of Toluene
The critical pathways for the known releases of toluene to the
environment are shown in Figure 4-5. These pathways are called
"critical" because they define the processes that reduce the total
environmental load of toluene.
The three critical pathways are: 1) atmospheric sources •* oxida-
tive destruction, 2) aquatic sources •*• volatilization •*• oxidative de-
struction, and 3) land sources •+• volatilization •* oxidative destruction.
Of the total estimated releases of 1,090,000 kkg in 1978, a maximum
of 99.8% may follow the shortest (i.e., no intermedia transfer) pathway—
#1; 0.001% may follow #2, and 0.0012% may follow #3. Part of these
releases will remain in each compartment as ambient or background levels
until either biodegradation or entrance to a critical pathway occurs.
4-38
-------
Usetof
Solvents
4> '
vo
Notes: Processes in boxes and bold type are major Idle (lalhways
(or ciy toluene in tliat particular medium.
Processes that lead to other media are indicated by an
airow. which leads to that medium and implies thai
all fate processes for the medium apply.
°" >fl Gasoline
S"ills \ Spills
33% \ 55%
Coal
Coking
5%
Atmospheric Sources
1.090,600 kkg
Oxidation
Destruction
Aquatic Sources
1.200 kkg
Volatilization
Land Sources
1.300 kkg
Biodugradation
Adsorption to Sediments and Soils
L*. Soil
Volatilization
II*. Biodeyradation
Leaching and Runoff
Water
FIGURE 4-5
CRITICAL PATHWAYS FOR TOLUENE
(Released Amounts for 1978 Materials Balance)
-------
REFERENCES
Altshuller, A.P.; Bellar, T.A. Gas chromatographic analysis of hydro-
carbons in che Los Angeles atmosphere. J. of Che Air Pollu. Cone.
Assoc. 13(2):81-87; February 1963.
Altshuller, A.P.; Lonneman, W.A.; Sucterfield, F.D.; Kopcynzski, S.L.
Hydrocarbon composition of che atmosphere of Che Los Angeles Basin.
Env. Sci. Technol. 5(10):1009; 1371.
Altwicker, E.R.; Whitby, R.A.; Stasivk, M.N. Ambient hydrogen levels at
two elevated and some street-level sices. Proceedings of Che 4th
International Clean Air Congress; 1977. pp. 520-523. (As cited in
Suta 1980)
Arthur D. LiCCle, Inc. Drafc Reporc. Exposure and risk assessmenc for
benzene. Washington, DC: Office of Water Regulations and Standards,
U.S. Environmental Protection Agency; 1980.
Berry, W.O. A comparative study of Che uptake of toluene by bluegill
sunfish Lepornis macrochirus and crayfish Orconectus rusticus. Environ.
Pollut. 13(3):299-234; 1977.
Berry W.O.; Fisher, J.W. Transfer of toluene^ (from mosquito larvae
to bluegill sunfish) Bull. Environ. Contamin. Toxicol. 23(6):733-736;
1979.
Bertsch, W.; Anderson, £.; Holzer, G. Trace analysis of organic volatiles
in water by gas chromatography-mass spectrometry with glass capillary
columns. J. Chromotag. 112*:701-718; 1975. (As cited in Suta 1980)
Brass, H. Community water supply survey (CWSS). Cincinnati, OH:
Office of Drinking Water, U.S. Environmental Protection Agency; 1981.
Buikema, A.L.; Hendricks, A.C. Benzene, xylene, and toluene in aquatic
systems: a review. Washington, DC: American Petroleum Institute; 1980.
Callahan, M.A.; Slimak, M.W.; Gabel, N.W. Water-related environmental
rate of 129 priority pollutants. EPA-44014-0292. Washington, DC:
U.S. Environmental Protection Agency; 1979.
Carlson, R.M.; Caple, R. Organochemical implications of water chlori-
nation. Water chlorination: environmental input and health effects,
Jolley, R., ed., Ann Arbor, MI: Ann Arbor Science Publishers; 1978.
Chambers, C; Tabak, H.; Dabler, P. Degradation of aromatic compounds
by phenol-adapted bacteria. J. Water Pollut. Control. Fed. 35:1517-1528;
1963. (As cited in Buikema and Hendricks 1980)
4-iO
-------
Dimitriades, B.; Wesson, T.C. Reactivity of exhaust aldehydes. J. Air
Pollution Control Assoc. 22:33-38; 1972.
Dowty, B.J.; Carlisle, D.R.; Laseter, J.L. New Orleans drinking water
sources tested. Gas chromatography-sass spectrometry. Environ. Sci.
Technol. 9 (8):762-765; 1975.
Feiler, H. rate of priority pollutants in publically owned treatment
works. Interim report. Washington, DC: Effluent Guidelines Division,
U.S. Environmental Protection Agency; 1980.
Grob, K. Gas chrornatography of cigarette smoke. Part III. Separation
of the overlap region and particulate phase by capillary columns. J.
Gas Chromatogr. 3:52-56; 1965.
Harden, J.M.; Hardison, D.L.; Wagoner, D.E. Organic scenario analysis
for samples collected in Lake Charles, Louisiana. RTI/1460/71-OIF.
Research Triangle Park, SC: Research Triangle Institute; no date.
(As cited in Suta 1980)
Claus, D.; Walker, N. The decomposition of toluene by soil bacteria.
J. Gen. Microbiol. 36:107-122; 1964. (As cited in Callahan et al.
1979)
Coleaan, W.E.; Lingg, R.D.; Melton, R.G.; Kopfier, F.C. The occurrence
of volatile organics in the drinking water supplies using gas chroraa-
tography/mass spectrometry. In: Identi. Anal. Org. Pollut. Water.
Chemical Congress, North America; 1976: 305-327. (As cited in Suta
1980)
Crain, W.O.; Tang, C.S. Volatile components of roasted macadamia nuts.
J. rood Sci. 40:207-208; 1975. (As cited in NRC 1980)
Crutzen, P.J.; Fishnan, J. Average concentration of OH in the tropo-
sphere, and the budgets of CH^, CO, H9 and O^CC^. Geophys. Res. Lett.
4:321-324; 1977.
Davis, D.S.; Heaps, W.; Philen, D.; McGee, T. Boundary layer measurements
of the OH radical in the vicinity of an isolated power plant plume:
S02 and N02 chemical conversion times. Atmos. Environ. 13:1197-1203;
1979.
Hendry, D.G. Reactions of aromatic hydrocarbons in the atmosphere.
Herron, J.T.; Huie, R.E.; Hodgeson, J.A., eds. Chemical kinetic data
needs for modeling the lower troposphere: proceedings of a workshop held
at Reston, VA; pp. 85-91. May 15-17, 1978, NBS Special Publication 557.
Washington, DC: U.S. Department of Commerce, 1979.
Heuss, J.M.; Glasson, W.A. Hydrocarbon reactivity and eye irritation.
Environ. Sci. Technol. 2:1109-1116; 1968.
4-41
-------
Koshino, M.; Akimoto, H.; Okuda, M. Photochemical oxidation of benzene,
toluene and ethylbenzene initiated by hydroxyl radicals in gas phase.
Bull. Chem. Soc. Japan 51:718-724; 1978.
Jefccate, C.R.; Lindsay-Smith, J.R.; Norman, R.O. Oxidation of some
benzenoid compounds by Fenton's reagent and the ultraviolet irradiation
of hydrogen peroxide. J. Chem. Soc. B. 1013-1018; 1969.
Johnstone, R.K.; Quan, P.M.; Carruthers, W. Composition of cigarette
smoke: some low boiling components. Nature 195:1267-1269; 1962. (As
cited in NRC 1980)
Jungclaus, G.A.; Lopez-Avila, V.; Hites, R.A. Organic compounds in an
industrial wastewater: A case study of their environmental impact.
Environ. Sci. Technol. 12 (1)88-96; 1978.
Keith, L.H., et al. Identification of organic compounds in drinking
water from thirteen U.S. cities. In: Idenf. Anal. Org. Pollut. Water.
Chemical Congress, North America; 1976: 329-373. (As cited in Suta
1980)
Kenley, R.A.; Davenport, J.E.; Hendry, D.J. Hydroxyl radical reactions
in the gas phase. Products and pathways for the reaction of OH with
toluene. J. Phys. Chem. 82:1095-1096; 1973.
Kim, N.K.; Stone, D.W. Organic chemicals in drinking water. Albany,
NY: New York State Department of Health; 1979.
Kinlin, T.E.; Muralidhara, R.; Pittet, A.O.; Sanderson, A.; Walradt,
J.P. Volatile components of roasted filberts. J. Agric. Food Chem.
20:1021-1028; 1972*. (As cited in NRG 1980)
Kleopfer, R.D. Analysis of drinking water for organic compounds. Identif.
Anal. Org. Pollutant. Water. Chemical Congress, North America; 1976:
399-416. (As cited in Suta 1980)
Kopfler, F.C.; Melton, R.E.; Mullaney, J.L.; Tardiff, R.G. Human ex-
posure to water pollutants. Proceedings of the American Chemical Society,
Division of Environmental Chemistry; Philadelphia, PA; 1975 April 6-11.
(As cited in Suta 1980)
Korn, S.; Strahsaker, J.W.; Benville, P. The uptake, distribution and
14C toluene in Pacific herring, Clupea harengous pallasi. Fish Bull.
75(3):633-636; 1977.
Leonard, M.J.; Fisher, E.L.; Brunell, M.F.; Dickerson, J.E. Effects of
the motor vehicle control program on hydrocarbon concentrations in the
central Los Angeles atmosphere. J. Air. Pollut. Control Assoc. 26(4):
359-363; 1976. (As cited in Suta 1980)
4-42
-------
Levins, P.; Adams, J.; Brenner, P.; Coons, S.; Harris, G.; Jones, C.;
Thrun, K.; Wechsler, A. Sources of toxic pollutants found in influents
to sewage treatment plants. Washington, DC: U.S. Environmental Pro-
tection Agency; 1979.
Lonneman, W.A.; Bellar, T.A., Altshuller, A.P. Aromatic hydrocarbons
in the atmosphere of the Los Angeles Basin. Environmental Science and
Technology 2 (11)1017-1020; 1968.
National Research Council (NRC). The alkyl benzenes. Washington, DC:
National Academy Press; 1980.
Nursten, H.E.; Sheen, R. Volatile flavor components of cooked potato.
J. Sci. Food Agric. 25:643-663; 1974.
O'Brien, R.J.; Green, P.J.; Doty, R.M. Comment on the reactions of
aromatic compounds in the atmosphere by D.G. Hendry. Herron, J.T.;
Huie, R.E.; Hodgeson, J.A. eds. Chemical kinetic data needs for modeling
the lower troposphere: proceedings of a workshop held at Reston, VA,
1978; May 15-17, NBS Special Publication 557. Washington, DC: U.S.
Department of Commerce, Washington, DC; 1979.
Pellizzari, E.P. Information on the characteristics of ambient organic
vapors in areas of high chemical production. Research Triangle Park,
NC: Research Triangle Institute; 1979. (As cited in Suta 1980)
Pilar, S.; Graydon, W.F. Benzene and toluene distribution in Toronto
atmosphere. Environmental Science and Technology 7(7):628-631; 1973.
Robinson, E.R.; Rasmussen, A.; Westberg, H.H.; Holdren, M.W. Nonurban
nonmethane low-molecular weight hydrocarbon concentrations related to
air mass identification. J. Geophysical Research 78(24):5345-5351;
1973.
Russel, P.A., ed. Denver air pollution study - 1973. EPA-600/9-77-001,
Washington, DC: U.S. Environmental Protection Agency; 1977.
Sax, N.I. Dangerous properties of industrial materials. 5th ed. New
York, NY: Van Nostrand Reinhold Company; 1979.
Scheiman, M.A.; Saunders, R.A.; Saalfeld, T.E. Organic contaminants in
the District of Columbia water supply. Biomedical mass spectrometry
1:209-211; 1974. (As cited in Suta 1980)
Sexton, K.; Westberg, H. Ambient hydrocarbons and ozone measurements
downwind of a large automotive painting plant. Environ. Sci. and
Technol. 14(3):329-332; 1980.
4-43
-------
Sheldon, L.S.; Kites, R.A. Organic compounds in the Delaware River.
Environ. Sci. Tec. 12(10)1188-1194; 1978.
Singh, H.3.; Salas, L.J.; Smith, A.; Stiles, R.; Shingelahi, H. Ataor-
spheric measurements of selected toxic organic chemicals. Research Tri-
angle Park, NC: Environmental Science Research Laboratory, U.S. Environ-
mental Protection Agency; 1979.
Singh, H.B.; Salas, L.J.; Smith, A.; Stiles, R.; Shigeishi, H. Atmo-
spheric measurements of selected hazardous organic chemicals. Second
year interim report. Research Triangle Part, NC: Environmental Science
Research Laboratory, U.S. Environmental Protection Agency; 1980.
Southworth, G.R. The role of volatilization in removing polycyclic
aromatic hydrocarbons from aquatic environments. Bull. Environ. Contam.
Toxicol. 21:207-214; 1979.
Spicer, C.W.; Jones, P.W. The fate of aromatic hydrocarbons in photo-
chemical smog systems: Toluene. J. Air. Pollut. Control Assoc. 27:1122-
1125; 1977.
Stanford Research Institute (SRI) Estimates of physical chemical con-
stants. Menlo Park, CA: Stanford Research Institute; 1980.
Stephens, H.N.; Roduta, F.L. Oxidation in the benzene series by
gaseous oxygen; the oxidation of tertiary hydrocarbons. J. Am. Chem.
Soc. 57:2380-2381; 1935. (As cited in Suta 1980)
Stevens, K.L.; Bomben, J.L.; McFadden, W.H. Volatiles from grapes
vitis vinitera (Linn.) cultivar grenache. J. Agric. tood Chem. 15:378-
380; 1967.
Suffett, I.H.: Radziul, J.V. Analysis of organic pollutants in drinking
water. Proceedings of the International Conference of Environmental
Sensing and Assessment; 1975 September 14-19, Las Vegas, SV.
Suta, B.E. Nonoccupational exposures to alkylbenzenes from their use as
solvents. Menlo Park, CA: Stanford Research International; 1980.
Thomas, R.G. Volatization from soil. In Handbook of Chemical Property
Estimation Methods. Ed. W.J. Lyman, W.F. Reehl, D.H. Rosenblatt,
McGraw Hill; 1981.
Turner, D.B. Workbook on atmospheric dispersion estimates. No. 99-AP-
26. Washington, DC: U.S. Public Health Service; 1969.
U.S. Environmental Protection Agency (U.S. EPA). Preliminary assessment
of suspected carcinogens in drinking water; Report to congress, December
1975. Washington, DC: Office of Toxic Substances, U.S. Environmental
Protection Agency; 1975.
4-44
-------
U.S. Environmental Protection Agency (U.S. EPA). National Organic Moni-
toring Survey (NOMS). Washington, DC: U.S. Environmental Protection
Agency; 1973.
U.S. Environmental Protection Agency (U.S. EPA). Survey of two municipal
wastewater treatment plants for toxic substances. Cincinnati, OH:
Wastewater Research Division, U.S. Environiaetnal Protection Agency;
1977.
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for toluene. Washington, DC: Office of Water Regulations
and Standards, U.S. Environmental Protection Agency; 1979.
U.S. Environmental Protection Agency (U.S. EPA). STORET. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980.
Versar, Inc. Gross annual discharge (GAD) to the waters in 1976. Report
No. 29. Toluene. Washington, DC: U.S. Environmental Protection Agency;
1977.
Verschuren, K. Handbook of environmental data en organic chemicals.
Sew York, SY: Van Sostrand Reinhold Co.; 1977.
Walradt, J.P.; Pittet, A.O.; Kinlin, T.Z.; Muralidhara, R.J.; Sanderson,
A. Volatile components of roasted peanuts. J. Agr. Food Chen. 19:972;
1971. (As cited in Suta 1980).
Weast, R. ed. Handbook of chemistry and physics. 55th ed. Cleveland,
OH: Chemical Rubber Company; 1975.
Wei, K.5.; Adelman, A.H. The photooxidation of toluene. The role of
an excited charge-transfer complex. Tetrahedron lett. 38:3297-3300;
1969.
Wilson, J.T.; Enfield, C.G.; Dunlap, W.J.; Crosby, R.L.; Foster, D.A.;
Baskin, L.B. Transport and fate of selected organic pollutants in a
sandy soil. Undated manuscripts received as personal communication from
Robert S. Kerr, Environmental Research Laboratory, Ada, OK, U.S. Environ-
mental Protection Agency; 1980.
i-45
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5.0 HUMAN EFFECTS AND EXPOSURE
5.1 HUMAN EFFECTS
5.1.1 Pharaacokinetics
5.1.1.1 Absorption
Toluene has volatile and highly lipid-soluble, chemical character-
istics that permit absorption by all exposure routes: inhalation,
dermal, and oral. The concentration of toluene and the permeability
of toluene of the intervening membranes determine the rate at which
toluene is absorbed.
Absorption of toluene by inhalation is the most important exposure
route in the occupational setting, because toluene is a commonly used
and highly volatile solvent. Several groups of investigators have
studied the pulmonary uptake of toluene and observed that the uptake
was rapid and markedly increased during exercise. Veulemans and
Masschelein (1978a) have made the most detailed and accurate measure-
ments of respiratory uptake. They found that the respiratory uptake
rate of toluene was directly proportional to minute volume and concen-
tration. The range of experimental minute volumes varied from a rest
rate of 7 1/min to >50 1/min under a heavy work load. The concentrations
varied from 190 to 750 cg/m^. The retention factor for toluene was 47%.
The retention factor is defined as the fraction (or percent) of the
inhaled solvent that is absorbed from the inspired air. The total
respiratory uptake of toluene into the body is estimated by the following
equation:
uptake (oig) = concentration (mg/m3) x minute volume (m3/min) x
retention factor (0.47) x time (minutes).
Dermal absorption of toluene vapor is slow compared with inhalation
at the same air concentration. Riihimaki and Pfaffli (1978) studied
the absorption of toluene across the body surface of human volunteers at
a concentration of 2260 mg/m3. The subjects were exposed for 3.5 hours
and their faces were covered with an inhalation mask under slight posi-
tive pressure to prevent inhalation uptake. They were clothed only in
lightweight pajamas and socks. These researchers calculated total
uptake as ^26 milligrams, based on a 16% recovery of absorbed dose in
the expired air. It is estimated that the same total uptake in 3.5
hours via inhalation would occur at an air concentration of only 38
mg/m3. (This estimate assumes a respiratory rate of 7 1/min at rest
and a respiratory retention factor of 47% for toluene.) In their
experiments on the percutaneous absorption of xylene vapor, Riiminiaki
and Pfaffli showed that dermal uptake is proportional to air concen-
5-1
-------
tration. Based on these data and the similarities between xylene and
toluene, the approximate average skin permeability of the human body
to toluene is calculated to be 0.002 m3/(ia2 x hr).l
Dermal absorption of liquid (neat) toluene is much faster than that
of vapor, because of the higher concentration and a defatting action on
skin that would significantly increase the permeability. Sato and
Nakajima (1978) conducted experiments on human volunteers in which
each individual soaked one hand in neat toluene for 30 minutes. Blood
levels after the 1/2-hour exposure reached approximately 25% of the
blood levels measured after 1/2-hour inhalation exposure at 376 mg/m3.
It can be shown that blood level is approximately directly proportional
to uptake rate, when that rate is constant. If it is assumed that the skin
absorption rate was constant (an oversimplification, but useful for an
approximation), it is estimated that the uptake rate via the skin of the
hand was ^20 mg/hr.2 The surface area of the hand is ^2% of the body
surface area of 1.8 n2 or 0.036 m2 (Dies and Lentner 1971); therefore;
an estimate of absorption rate through skin of liquid toluene is 550
mg/m2 hr.
Oral absorption can be expected to approach 100%. The absorption
rate depends on gastric contents and gastric emptying. Pyykko and co-
workers (1977) found peak blood levels of radioactivity at 2 hours
following gastric intubation to rats of 14C toluene mixed with peanut
oil. Oral exposure differs from both dermal and inhalation exposure
because of the "first-pass effect". Intestinally absorbed toluene
passes through the hepatic-portal circulation before entering the gen-
eral circulation. Because the liver is a principal organ of the
metabolism of toluene, blood levels of unchanged toluene would be
somewhat lower than following intravenous injection or inhalation
absorption of an equivalent dose. The influence of the first-pass
effect on the response of the organism to toluene has not been deter-
mined. This detail is not considered critical at this time, because
oral absorption of toluene normally constitutes a relatively small
proportion of total exposure. For purposes of this report, it is
assumed that the absorption route has no significant influence on
effect, and that effect depends only on the rate or the total amount
absorbed.
uptake » \6J"jj • permeability x 2260 mg/m3 x 1.8 m2, 26 mg/3.5 hr
j • j mr
where 2260 mg/m3 was the exposure concentration and 1.8 m3 is the
appropriate body surface area.
376^mg/m3 x <47 x Ot45 n3/hr = 2Q mg/hr, where 376 ^/m3 was the air
concentration for equivalent blood levels via inhalation, .47 was the
respiratory retention factor; and 0.45 ai3/hr, the respiratory rate at
rest.
5-2
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5.1.1.2 Distribution
In discussing the distribution in the body of a lipid-soluble,
water-insoluble compound, it is appropriate to view the body as a
nulticompartaental system. Although each organ may be considered a
compartment, it is more usual to treat the body as containing 2-4
compartments, with each compartment mace up of organs and tissues
having similar pharmacokinetic characteristics. For toluene, a 3-
compartment model has generally been adequate to characterize the
pharrnacokinetics. The first compartment is generally considered to be
composed of the vascular space and highly perfused organs, such as the
heart, kidneys, liver, intestines, endocrine glands, and brain. This
compartment is called the central compartment, because it is the one
from which the other compartments, called peripheral compartments,
receive drugs and chemicals and from which the chemicals are eliminated
from the body. The second compartment is composed of tissues and organs
with moderate blood perfusion, such as muscle and skin. The third
compartment, especially important in the case of lipid-soluble organics,
is composed of slowly perfused tissues, such as fat. Fat differs from most
other tissues in having a much higher tissue/blood partition coefficient
for organic solvents; i.e., it can accumulate toluene to a greater extent
than might be expected on the basis of volume alone.
A useful index of the time it takes for the various tiusses (or
compartments) to reach equilibrium with the central compartment (i.e.,
the blood, because it can be assumed that rapid mixing occurs within
the central compartment) is the saturation half-life, ts/2* The
saturation half-life depends directly on volume of the compartment
(Vf) and the tissue/blood partition coefficient (A); and inversely on
the blood flow (Q) for the compartment as follows:
ts/2 • 0\ • VT/Q) x 0.693.
Rough estimates of saturation half-lives for several tissues and
the three composite compartments are presented in Table 5-1. Clearly,
the distribution to the brain and the central compartment is very rapid.
It is so rapid that often it is difficult to delineate this compartment
in pharmacokinetic analysis. The third compartment equilibrates so
slowly that it does not reach saturation equilibrium with the blood
during continuous exposure, such as an 8-hour occupational exposure.
For this reason, a tendency for "baseline" blood levels to build up
over continuous day-to-day exposure could occur as a result of this
third compartment being similarly slow.
Usually, blood levels cannot be used to quantitate absorption
unless exposure conditions in terms of both concentration and time
are known. During inhalation exposure, blood levels rise very rapidly
to a "quasi"-steady state, reflecting rapid absorption and slow
metabolism and distribution to other tissues. When exposure is term-
inated, blood levels fall rapidly at first, reflecting continued dis-
5-3
-------
TABLE 5-1. ESTIMATES OF THE SATURATION HALF-LIFE
OF TOLUENE BETWEEN BLOOD AND TISSUE
VT/Q
Compartment 1
Liver
Kidney
Brain
Compartment 2
Compartment 3
Fat
Marrow
NOTE;
* = Tissue/blood partition coefficients obtained from data of
Sato et al. (1974)
VT/Q = Volume of tissue/blood flow (ml/ml/min) from Papper and
Kitz (1963).
ts/2 • Saturation half-life• 0.693 x VT/Q x \ (minutes).
Toluene
2
2.6
1.5
3.0
1.2
,100
If
113
35
1.5
2.5
.24
1.3
17
(resting)
47
t .'
50
25
Toluene
2
4.5
0.2
2.7
13
3200
3900
850
5-4
-------
tribution to the rest of the body as veil as metabolism and elimination.
After the initial rapid decline, slower phases of decline are noted,
because elimination is rate limited by the transfer of the chemical
from the peripheral compartments into the central compartment.
Sato and ccworkers (1974) studied and compared the phamacokir.etics
of benzene and toluene in human volunteers. The decline in blood levels
after a 2-hour exposure to either benzene (at 80 mg/m3) or toluene (at
377 mg/m-3) was followed for 5 hours. The equations that describe the
decline in blood levels are sums of three exponentials as follows:
benzene
-0.418t . „ n0f -0.0238t . „ «„„- -0.00347t
y = 0.0593e "••'""• + 0.086e «•«*•""• + 0.0287e
toluene
T~ = 0.355e-°-355t + 0.352e-°-0197c + 0.129e-°-00339t;
where t is time in minutes and y is blood concentration in ag/1.
These model equations, together with other data, indicate that
benzene and toluene are absorbed and distributed into the body
in a similar manner. The exponents of the equations are similar to
a striking degree. Also, the coefficients of the toluene equation
are about 4-6 times higher than the respective coefficients in the
benzene equation, which is a result of the toluene exposure concen-
tration being 4.7 times the benzene exposure concentration.
In an important respect, the equations are probably misleading for
both toluene and benzene, because they suggest no appreciable accumu-
lation of either solvent fron day to day. Konietzko et_ al. (1980)
and theoretical considerations indicate that accumulation can occur
on a daily basis. Konietzko monitored exposure concentrations and
blood concentration levels of toluene at the beginning and end of each
8-hour work day over a 2-week period in workers occupational!-/ exposed
to toluene. These data are reported in Table 5-2. An apparent upward
trend in the toluene blood concentration values occurs each morning
before exposure over the 5-day work week. The lowest levels were
measured on Monday mornings. The half-life of the terminal phase of
elimination would have to be on the order of 2000 minutes (30 hours)
for baseline blood levels to build up as they did in the exposed workers.
This half-life is comparable with the theoretical saturation half-life
for fat given in Table 5-1. The terminal phase half-life calculated
from the equations of Sato et al. (1974) are on the order of 200 minutes.
This finding of Sato and coworkers is understandable because the exposure
was only for 2 hours in their experiments and the blood concentration
data were only determined for 5 hours after the exposure. These time
periods are too brief to delineate a very slow elimination phase.
-------
TABLE 5-2. TDI.UKNK CONCENTRATIONS IN Alii AND BLOOD
Ol
I
First Week: Toluene in air (ppm)
Toluene In blood
- before exposure (eg/ml)
- after exposure
Second Week: Toluene In air (ppm)
Toluene In blood
- before exposure (ug/ml)
- after exposure
Monday Tuesday
225 233
(95-303) (153-383)
0.12
(0.09-0.24)
3.63
(2.3-4.75)
285 304
(145-473) (190-521)
0.27
(0.07-0.57)
11.60
(6.99-17.10)
Wednesday Thursday
209 212
(107-341) (92-314)
0.51
(0.28-0.82)
6.69
(4.21-10.36)
309 232
(213-413) (125-451)
1.00
(0.35-1.51)
10.29
(3.24-20.31)
I'riday
203
(124-309)
0.77
(0.29-1.67)
6.70
(3.39-10.67)
191
(105-432)
1.21
(0.44-2.99)
5.85
(1.94-9.78)
Range In parentheses and means for eight subjects.
Source: Konletzko et al. (1980).
-------
In summary, toluene is absorbed into the body regardless of the
route; the major difference among routes is the rate of absorption.
Once toluene is in the blood, it is distributed widely to all tissues;
the relative perfusion of the tissue by blood determines the relative
rate of uptake into each tissue. Accumulation in fat is slow because
of low perfusionj however, the potential uptake is high because of
the lipid solubility of toluene.
To a first approximation, acute effects depend on blood concentration
regardless of the route. Absorbed doses via dermal, oral, and inhalation
routes are approximated as follows:
dose (dermal/liquid) = 550 mg/m^/hr x exposed surface area (m^) :;
time (hour);
dose (dermal/vapor) = 0.002 nrV(m2 x hr) x esposed surface area
(m^) x time (hour) x concentration (mg/ra^);
dose (oral) - amount ingested;
dose (inhalation) = 0.47 x inhalation rate x time x concentration,
0 0.56 x hours x concentration (mg/nr) .
5.1.1.3 Metabolism and Elimination
The metabolism of toluene in humans is outlined in Figure 5-1.
Except for differences in the proportion of toluene eliminated by the
various pathways, the metabolism in animals is essentially the same.
The major routes of toluene elimination in humans are metabolism to
hippuric acid, and exhalation of unchanged toluene. These two routes
account for about 80 and 16%, respectively (Veulemans and Masschelein
1978a, 1979).
The initial oxidation of toluene to benzyl alcohol occurs by mixed
function oxidase system, which is associated with the microsomal
fraction from tissue homogenates. Phenobarbital can induce this
enzyme system (Ikeda and Ohtsuji 1971). More importantly, a number
of substrates can competitively inhibit it. Ikeda (1974) reported
reciprocal metabolic inhibition of toluene and trichloroethylene in rats
at high dose levels (430 rag/kg toluene, 730 mg/kg trichloroethylene).
Ikeda et_ al. (1972) reported in vivo suppression of benzene and styrene
oxidation by coadministration of toluene in rats, which could be partially
reversed by pretreatment of rats with phenobarbital.
Sato and Nakajina (1979) studied the dose-dependent interaction
between benzene and toluene in rats and in human subjects. In rats,
they found slight to no competitive inhibition between toluene and
benzene at doses <115 mg/kg for each compound. At 460 cig/kg for both
The figure 0.56 assumes 1.2 mVhr inhalation rate during moderate
physical activity.
5-7
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Figure 5-1 Metabolism of Toluene in Humans
CH.
80%
Expired Air
CH2OH CHQ
COOH CONKCH2COOH
benzyl benzaldehyde benzoic hippuric
alcohol acid acid
arene oxides
^ o-cresol
? ^- m-cresol
^ p-cresol
V
glutachione conjugate*
benzyl mercapcuric acid
5-8
-------
toluene and benzene, significant competitive inhibition occurred. Tolu-
ene inhibited benzene metabolism more readily than vice versa. In their
studies on human subjects, these authors found no metabolic interaction
between benzene at 25 ppm (80 mg/m^) and toluene at 100 ppm (376
Riihimaki (1979) found that the apparent rate-limiting step in the
metabolism and excretion of toluene to hippuric acid was the conjugation
of benzoic acid with glycine, which had a maximum rate of 1190 umol/min
(M.7 mg/min). Riihimaki (1979) estimates that saturation of glycine
conjugation would not occur in an average 70 kg, well-nourished male
until air concentrations approached 780 ppm ( ^2900 mg/nr) under light
work conditions. Under moderately heavy work conditions, uptake would
be increased so that saturation would be obtained at lower air concen-
trations (e.g., 1000 mg/m^ at an uptake ^3 times higher than during
light work). Riihimaki (1979) points out, however, that the availability
of glycine may be less in older persons , undernourished individuals , and
individuals taking drugs that compete for its availability. Under
competitive conditions, it may be the drug that will accumulate rather
than toluene.
Urinary excretion of hippuric acid has been correlated with toluene
exposure by a number of researchers (Ogata et al. 1970, Sato and Nakajima
1979, Angerer 1979, Riihimaki and Pfaffli 1978, Wilczok and Bieniek 1978,
Lehnert et al. 1978); however, it is apparent from these studies that
the usefulness of urinary excretion data is limited. The major difficulty
is obtaining a complete urine specimen, both during exposure and for up
to 12 hours after the end of exposure. Moreover, hippuric acid is a normal
constituent of urine, and its excretion can be quite variable. Veuletaans
and Masschelein (1979) conducted a strictly controlled experiment by
prescribing the exclusion of alcohol and coffee for 16-20 hours before
the beginning of their experiments. They reported baseline hippuric
acid excretion averaging 0.5 g/day. Angerer (1979) reported that in
28 unexposed subjects, hippuric acid concentration averaged 0.96 g/1
with a standard deviation of 0.94 g/1. If hippuric acid excretion were
to be used as an index of exposure, certain approximations and standard-
ization procedures would have to be used (Ogata et al. 1970) and it
would appear that the precision would still depend on the completeness
of the urinary collection as well as the maintenance of a standard
technique calibrated against known exposure and excretion.
Minor routes of toluene metabolism in humans result in the excretion
of o-, p-, and m-cresol and presumably (although not identified) benzyl
mercapturic acid in the urine. Angerer (1979) identified o-cresol in
the urine of printing workers exposed to an average air concentration
of toluene of 23 ppm (87 mg/m^) . This metabolite was not considered
a normal constituent of urine. Urine levels of combined a- and p-cresol
in exposed workers were slightly, but not significantly, greater than
levels from unexposed workers.
5-9
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Woiwode and coworkers (1979) identified o-, m-, and p-cresol in
the urine of workers exposed to 280 ppm (1050 mg/m3). Urine was col-
lected during the work shift. Expressed as a percent of total urinary
metabolytes, having subtracted control levels, hippuric acid constituted
98% of the total; p-cresol, 2%; 0-cresol, 0.2%; and m-cresol 0.08%.
Mo o- or m- cresol was identified in the urine of unexpcsed workers.
Pfaffli and coworkers (1979) in a study on exposed and unexposed
printing workers, found a correlation (r • 0.8) between air concen-
trations of toluene (0.3-4.5 mg/m^) and o-cresol excretion in urine
(urine sample at end of workshift).
Findings in animal experiments indicate that similar metabolic
processes occur. Bakke and Scheline (1970) dosed rats at 100 mg/kg
and identified o- and p-cresols in urine ranging from 0.04 - 0.11% and
0.4 to 1.0% of dose for o- and p-cresols, respectively. They could
not detect m-cresol. The sensitivity of their methods was not discussed.
Van Doom and coworkers (1980) identified the urinary metabolite, benzyl
•nercapturic acid in experiment on rats, which were dosed intraperitoneally
with 368 mg/kg toluene in arachis oil (peanut oil). The benzyl nercap-
turic acid excretion represented between 0.4 and 0.7% of the dose.
Of interest and possible concern is the fact that all the minor
metabolytes, the cresols, and mercapturic acids result from the oxidation
of the aromatic ring by a mixed function oxygenase system, which is
processed to occur via reactive intermediates variously called arene
oxides or aromatic epoxides. They may rearrange spontaneously to form
phenols (methyl phenol in the case of toluene) or react with other
cellular constituents. In the case of mercapturic acid formation, the
intermediate is thought to react with glutathione via enzyme systems
called glutathione S-transferases (Goldstein 1974).
A discussion concerning the relative carcinogenic potency of aro-
matic hydrocarbons, particularly the polycylics, in relationship to the
metabolism via the arene oxide intermediates is highly complex and is
inappropriate at this time, because no evidence exists that toluene is
carcinogenic. Although metabolism appears to be important, both in the
activation of carcinogenic aromatic hydrocarbons and in the activation
of an active parent and intermediate compounds, evidence of the forma-
tion of arene oxides is not evidence of carcinogenicity. In the case
of toluene, a small proportion of the dose is handled in this manner.
Research will no doubt continue to explore the possible role of arene
oxides in toxicity and carcinogenicity. No .definitive conclusions with
regard to toluene are forthcoming at this time.
5.1.2 Acute Effects
Toluene is a general central nervous system (CMS) depressant. This
property, associated with its low toxicity and high volatility, has caused
toluene to become a preferred solvent of abuse (see further discussion
below). Inhalation exposure can progressively lead through stages of
5-10
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CMS depression resembling, for the most part, the stages of anesthesia:
Stage I — light-headedness, euphoria, drunkenness, ataxia, slurred
speech; Stage II — loss of consciousness, delirium, excitement, involun-
tary activity such as thrashing about, incontinence of urine and feces,
vomiting, hypertension and tachycardia; Stage III — anesthesia with
regular autonotaic-controlled breathing, loss of most reflexes, muscles
flaccid; Stage IV — respiratory paralysis and death.
The extent of CMS depression depends on the concentration and dura-
tion of exposure. Glue-sniffing and solvent abuse is intended by the
user to attain the euphoriant effects that can be achieved by several
deep breaths at near air-saturation concentrations of toluene (saturation
concentrations 100,000 - 200,000 mg/m3 between 20-30 °C). At lower
concentrations (estimated 40,000 - 120,000 mg/m3), men have been
rapidly overcome and fallen unconscious in occupational settings. Re-
covery is rapid if the person is removed from exposure; however, death
from respiratory failure may occur accidently in solvent abusers or in
occupational circumstances when the victims fail to or are unable to
remove themselves from the exposure (U.S. EPA 1980a).
Death may also occur from a sudden cardiovascular collapse, even
in the early stages of anesthesia. It is believed that these deaths
result from cardiac arrhythmias, which are induced by a combination of
hypoxia, physical stress, and sensitization by toluene of cardiac muscle
to catecholamines (Bass 1970, Taylor and Harris 1970, U.S. EPA 19SOa).
Upon acute exposure, toluene appears to have limited toxicity poten-
tial, other than CMS depression and predisposition of subjects to cardiac
arrhythmias. Investigations in cases of accidental exposures to very
high doses of toluene in humans and experimental studies in animals have
failed to reveal any significant pathologic changes in blood chemistries
or organ histopathology (U.S. EPA 1930a).
5.1.3 Chronic Effects
5.1.3.1 Myelotoxicity
Human epidemiological or animal experimental data have not clearly
indicated the myelotoxicity of toluene. In epidemiological studies
showing a possible effect from toluene exposure, coexposure to benzene
and other toxic chemicals cannot usually be ruled out as contributing
causes. Results in animal studies are quite contradictory. Possible
differences in species susceptibility and the likely contamination
of toluene with benzene, in particular, are two major confounding
variables.
Greenburg and coworkers (1942) compared 61 painters exposed prim-
arily to toluene (95% between 100-800 ppm or 380-3000 mg/m3, median
exposure concentration 750 mg/in3) with a control group for clinical
manifestations of toxicity. The exposed group had an increased inci-
5-11
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deuce of liver enlargement, macrocytosis (increased volume of RBC),
decreased erythrocyte counts, and lymphocytesis. Exposure was not
associated with leukopenia. Table 5-3 gives an analysis of the paints.
It is likely that these paints contained some benzene because it is
a common impurity in certain grades of toluene. Banfer (1961) reported
that toluene derived from coal tar may be contaminated with benzene by
as much as 15% and that toluene containing only traces of benzene (up to
0.3%) had been available since about 1955.
Powars (1965) reported on six cases of aplastic anenia associated
with glue-sniffing. Glue was claimed to contain toluene or acetone
(depending on the brand) according to the glue manufacturer. One case
had a 3-year history of glue-sniffing. The other cases were complicated
by the presence of sicklecell disease, although aplastic anemia was
stated to be rare with this disease. Powars concluded that glue sniffing
precipitated the onset of aplastic anemia. The estimated concentrations
of toluene of inhaled vapors during glue-sniffing are on the order of
12,000-24,000 mg/ni3.
Forni and coworkers (1971) did not find a significantly increased
incidence of chromosome aberrations in peripheral blood lymphocytes in
toluene-exposed workers compared with matched controls. The exposure
concentrations were on the order of 750 mg/m3; mean and median duration
were 10 years; and the range was 3-15 years. In contrast, workers
exposed to both benzene and toluene had a significantly higher incidence
of stable and unstable chromosome aberrations in peripheral blood. The
benzene exposure concentrations were not precisely known although they
were estimated to be in excess of 1500 mg/m3 during a recent epidemic of
benzene poisoning. Median duration of benzene exposure was 3 years. The
co-exposure to toluene were on the order of 750 mg/m3 with median dura-
tion of 14 years. Table 5-4 presents the incidence of unstable (Cu)
and stable (Cs) chromosome aberrations in the exposed groups and matched
controls.
Capellini and Alessio (1971) reported on clinical findings of 17
workers exposed to toluene (mean concentration 125 ppm or 470 mg/m3,
range 30-160 ppm or 300-600 mg/m^) for several years duration. Accom-
panied by regular medical supervision, no untoward changes were noted in
hemoglobin, red and white cell counts, platelet counts, and certain liver
function tests, compared with a control group not exposed to toluene.
Friborska (1973) reported altered cytochemical measures from leuko-
cytes and lymphocytes of toluene-exposed workers. Acid phosphatase
activity was significantly increased in lymphocytes, alkaline phosphatase
activity in leukocytes, and lactic acid dehydrogenase activity in leuko-
cytes from exposed workers compared with controls. The meaning of these
cytochemical changes is unclear.
Studies of the siyelotoxicity of toluene in animals are inconclusive.
A summary of findings in several studies is listed in Table 5-5 for
studies with negative findings and Table 5-6 for studies with adverse
effects reported. None of the positive studies was available in trans-
lation.
5-12
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TABLE 5-3. ANALYSIS OF PAINT USED BY PAINTERS3
Percentage
Spray Painters in Mixture
Priner (75% of paint used):
Zinc chrornate
Magnesium silicate
Synthetic resin
Driers (lead and cobalt compounds)
Xylene
Toluene
Lacquer 1 (15% of paint used):
Volatile Portion:
Ethyl alcohol
Ethyl acetate
Butyl alcohol
Butyl acetate
Petroluem naphtha
Toluene
Nonvolatile:
Nitrocellulose, synthetic resin, titanium oxide,
ferrocyanide blue, iron oxide, carbon black, zinc
oxide, etc. No lead compounds
Lacquer 2 (10% of paint used):
Volatile Portion:
Toluene
Xylene
Petroleum naphtha
Nonvolatile:
Resin, titanium oxide, zinc oxide, ultramarine blue,
ferrocyanide blue, iron oxide, diatomaceous earth,
amorphous silica, carbon black
5-13
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TABLE 5-3. ANALYSIS OF PAINT USED 3Y PAISTERS (Continued)
Brush Painters
Dope:
Volatile Portion:
Ethyl acetate
Ethyl alcohol
Butyl acetate
Butyl alcohol
Petroleum naphtha
Toluene
Nonvolatile:
Nitrocellulose, glycol sebaeate, aluminum, cadmium
sulfide, barium sulfate
Brush Wash:
Acetone
Ethyl alcohol
Toluene
uip painters used a primer only of the same composition as given
for spray painters.
Source: Greenburg e£ al. (1942).
5-14
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TABLE 5-4. FREQUENCY OF CHROMOSOME ABERRATIONS IN
PERIPHERAL LYMPHOCYTES
Frequency (%)
Cu Cs_
Toluene 0.8 p>.05 0.08 p>.05
Controls 0.67 0.09
Benzene and Toluene 1.7 p<.01 0.26 p>.05
Controls 0.61 0.00
Source: Forni et al. (1971).
5-15
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TABLE 5-5. ANIMAL STUDTliS OF MYKLOTOXICITY OF TOI.UKNK (Negative Studies)
in
Species (N)'
Rat
Kat
(6)
Kat
(30)
Kat
Kat (15)
Guinea pig (15)
Dog (2)
Monkey (3)
Kat (25)
Dog (/•)
Koute/Dosage
Oral/118, 354,
590 mg/kg,
5 d/wk. 24 weeks
Inhalation/
750, 3760
7500 ing/in3
8 lir/d, 32 weeks
Inhalation/0, 133,
370, 1130, 3760
6 hr/d, 5 d/wk,
13 weeks
Inhalation/O,
113,370,1130
6 hr/d, 5 d/wk,
18 months
Inhalation/4095
nig/m3, 8 hr/d,
5 d/wk, 6 weeks,
389 mg/m3 continuous
for 90 diiys
Inhalation/
0, 950, 1900,
3900 ing/in3 6 hr/
day x 13 weeks
Findings
Cell counts of marrow and
circulating blood revealed
no adverse effects.
No alterations In peripheral
blood counts.
No treatment effects: body
weight gain, food consumption
heinaLology, clinical chemistry,
iirinalysis, hlstopathology.
Significantly lower liver
weights In test animals except
at the highest dose.
No treatment effects as in
Khudy o£ al^ (1978). Final
results unpublished.
No significant changes
relative to control groups:
growth rate, leukocyte counts,
hemoglobin and hemocrlt.
No signif leant liom.ito logical
or cl In leal-chemistry changes
attributed to trealment.
References
Wolf et al. (1956)
Takciichl (1969)
Uhudy et_ aj_. (1978)
Gibson (1979)
Jenkins ct al. (1970)
Carpenter et al. (1976)
Number per dose level,
(-) = Unspecified.
-------
TABLE 5-6. ANIMAL STUDIES OK MYlil-OTOXTCITY (Positive Studies)
Species (N)
Mice
Ul
Kut
Kat
Kat
Route/Dosage
Tnlialation/6 d/wk,
4, 38, 380, 3800
mg/m-*
420 mg/m3,
4 hr/d, 4 months
Injection (route
unspecified),
Ig/kg/d, 12 days
Dermal/
10g/kB hw/d
]g/kg bw/d
Findings
l.eukocytosls at all dose
levels, decrease Jn erythro-
cytes at 380 and 3800, tlirorabo-
cytopenia at 38, 380, 3800,
slight hypoplastlc change in
bone marrow of group at the
highest dose.
(.eukocytosls and chromosome
damage in bone marrow.
Treatment
Toluene
Benzene
Control
Chromosome damaged
cells (%)
11.5
57.2
3.9
Impaired leukopoicsis as
evidenced by an increase in the
number of plasmlc and lymphoid
reticular cells in marrow.
No effect.
References
llorlguchl ut al. (1976)
DobrokhoLov and Enlkeev
(1977)
l.yapkalo (1973)
Yuslikevlch and Malysheva
(1975)
'Number per dose level.
(-) -= Unspecified.
-------
The U.S. EPA (1980a) concluded that the studies summarized in Table
5-6 (positive myelotoxic effects) should be interpreted with caution.
Although they cannot be entirely dismissed, questions of toluene
purity and details of experimental conditions and protocols, and the
difficulty in interpreting translations exist. Still, a substantial
number of studies in animals and humans has found no evidence of
toluene-induced myelotoxicity.
5.1.3.2 Central Nervous System Toxicity
Several case reports have associated permanent CMS damage with
glue-sniffing and solvent abuse. Because toluene was found to be a
ccicmon solvent in glues, it has been suspected as an etiological agent.
However, N-hexane is also a common glue solvent and has been associated
with certain neuropathies in the industrial setting (Towfighi et al. 1976)
Moreover, it is not uncommon for persons who sniff the vapors of glue to
have abused other solvents, such as gasoline, and to have experimented
with a variety of drugs of abuse. Thus, some reports conclude that
toluene is not the causative agent.
Towfighi e_t al. (1976) , Goto et al. (1974) , Shirabe et_ al. (1974)
and Suzuki et al. (1974) support the latter opinion. These reports have
attributed the neuropathies to N-hexane. The case histories revealed
that N-hexane was present in the glues preferred by the patients. The
symptoms are described as a sensory polyneuropathy and sensorizsotor
polyneuropathy. Towfighi et al. (1976) describe a patient who, for 5
years, had been sniffing glue containing toluene and other mixed petro-
luem distillates but not N-hexane. He had remained in good health but
then began using glue containing N-hexane. Over the next 2 months, he
noted a gradual onset of pain, tingling and weakness in the left leg and
then in the right leg. One year after discontinuing glue sniffing, he
still displayed a neurological deficit in the lower extremities.
Grabski (1961), Knox and Nelson (1966), Kelly (1975), Boor and
Hurtig (1977), and Keane (1978) attribute neuropathies, in certain cases
of chronic glue-sniffing or solvent abuse, to toluene. Knox and Nelson
(1966) reported a case of a person who used toluene purchased from a
local paint store. Analysis of the toluene paint thinner was not given.
After two years of virtually continuous abuse, he noted progressive
tremulousness and unsteadiness. He continued to inhale vapors of the
toluene thinner for at least another 5 years. Hospital admission,
because of injudicious substitution of carbon tetrachloride for toluene,
provided an opportunity for extensive neurological tests. These re-
vealed neuropathy, such as tremor, unsteady gait, and emotional explo-
siveness. Pneumoencephalograms revealed tissue loss from the cerebrum.
In another case, Kelly (1975) recorded data on a female patient who had
used particular brands of spray paints, most of which contained toluene.
'Other ingredients of the spray paints were not listed. The neurological
tests after 6 years of abuse were similar to the previous case. Five
months after discontinuing paint sniffing, the patient was improved al-
though she still exhibited an abnormal tandem gait.
5-18
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Other central-nervous-system effects have been associated with sol-
vent abuse; and it has been tentatively concluded that toluene is one of
the responsible agents. Such effects include emotional cr psychiatric
problems (Weisenberger 1977, Knox and Nelson 1966, Tarsh 1979) and one
report of optic neuropathy (Keane 1978). Spray-painters exposed to
toluene and other organics have been found to have modest neurological
deficits both functional and emotional (U.S. EPA 1980a). In all these
cases, a distinct attribution of the cause to toluene is not possible,
because concommitant exposure to other solvents and the contribution
of pre-existing problems have not or cannot be assessed.
The chronic CNS effects from solvent abuse occur at very high
exposure concentrations. Actual blood levels of toluene attained during
glue-sniffing or toluene abuse have not been reported. Knox and Nelson
(1966) estimated blood levels of 25 mg/1. Based on the relationship
between uptake and blood levels reported by Veulemans and Masschelein
(1978b), such blood levels would require air concentrations of 12,000-
24,000 mg/m3, depending on breathing rates. According to the several
reports on glue-sniffing or solvent abuse, high inhalation levels are
attained by dousing a rag with paint thinner or toluene and placing
it over the mouth and nose and taking multiple deep breaths. Alterna-
tively, glue is applied to the inside of a bag, the bag placed over the
mouth and nose, the person rebreathing the bag contents until the desired
effects are attained. Clearly, these exposure levels are extremely high.
Animal studies have not appreciably clarified the neurotoxic
potential of toluene. Only one study has attempted to examine the sub-
chronic effects of toluene on learning and memory. Although acute CNS
effects have been extensively studied, these only indicate temporary
effects. Of greater concern is the potential for permanent damage as
a result of chronic exposure.
Ikeda and Miyake (1978) studied the effects on memory and learning
in rats of exposure to toluene (4000 ppo or 15,000 mg/tn3, 2 hr/day for
60 days). Before the 60-day exposure, rats were taught both a continuous
reinforcement (CRT) schedule and a fixed-ratio schedule (FR30). In the
CRT schedule, every response (e.g., bar press) was rewarded (e.g., food),
while in the FR3Q, only a response every 30 seconds was rewarded. Rats
who master the FR3Q schedule learn only to press a bar a few times every
30 seconds. The FR3Q schedule is considered a more difficult schedule
to learn. Rats that learned both the CRF and FR3Q schedule were divided
into two groups, toluene-exposed and control. During the exposure period,
CRF and FR30 were monitored. No difference occurred in the CRF between
exposed and control rats; however, the FRjQ response became extinct in
the exposed rats by day 40. Spontaneous activity and emotionality,
which'was measured 4 days after the end of the 60-day exposure period,
were not significantly affected by the toluene exposure.
Seven days after the end of the exposure, a DRL 12-second schedule
was used to further distinguish exposed and control rats. In this test,
5-19
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only single responses every 12 seconds were rewarded. If an inter-
response interval was less than 12 seconds, a timer was reset to require
the rat to wait an additional 12 seconds. This schedule is more diffi-
cult to learn than the FR.3Q schedule. Ikeda and Miyake (1978) concluded
that impairment in learning the DRL 12-second and extinction of the
schedule was not because of perceptual or motor difficulty, based on a
similar performance in the CRT and activity measures. Rather, the
deterioration of more complex behavior and learning patterns were
attributed to a diffuse CMS impairment from toluene exposure.
5.1.3.3 Other Chronic Toxic Effects
Several long-term animal studies have not indicated that toluene
has appreciable residual toxic effects (Wolf et al. 1956, Takeuchi 1969,
Gibson 1979). Takeuchi (1969) did report a relative decrease in the
weight of the adrenal gland in rats exposed to 750, 3750, and 7500 mg/m3,
3 hr/day, every day for 32 weeks. The histopathology of the adrenal
glands revealed a thickening of the zona glomerulosa and a thinning of
the zonae faciculata and reticularius. Takeuchi (1969) suggested this
was a secondary hypofunction of the adrenal cortex because of suppression
of ACTH secretion. He also reported hyperplasia of the white spleen
marrow in the toluene-exposed groups.
5.1.3.4 Carcinogenicity
There are no reports of a carcinogenic response to toluene. In
skin-painting experiments, toluene is often used as a vehicle and a
control.
The U.S. EPA (1980b) remarked that the data base on the carcino-
genicity of toluene is extremely limited and is insufficient for
evaluating the carcinogenic potential of toluene.
rrei and Kingsley (1968) reported data that suggest toluene may
be a weak promoter of 7, 12-dimethyl benz (a) anthracene (DMBA) induced
mouse skin tumors. It was comparable in potency to mineral oil and 10%
oil of sweet orange in mineral oil, and significantly less potent than
turpentine, Tween-60 and 5% croton oil in mineral oil.
5.1.3.5 Reproductive Toxicity
There have been no reports of teratogenic effects in humans asso-
ciated with exposure to toluene.
Syrovadko (1977) reported a higher incidence of menstrual disorders
in a group of women occupationally-exposed to toluene and other solvents
through the use of varnishes. Babies born of these women were stated
to experience more frequent fetal asphyxia, to be more often under-
weight, and not to nurse as well as "normal" infants. Matsushita et al.
5-20
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(1975) reported that dysmenorrhea was a frequent complaint of female
shoemakers occupationally-exposed to 60 and 100 ppn (225 to 376 ag/m3)
toluene.
Several groups of investigators have examined the teratogenic and
fetotoxic effects of toluene in experimental animals. Recently, Nawrot
and Staples (1979) reported that toluene was teratogenic in CD-I mice.
Toluene was administered by gavage at 0.5 or 1.0 ml/kg/day during days
6-15 of gestation. At the 1.0 ml/kg dose, there was a statistically
significant increased incidence of cleft palate, which these investi-
gators said did not appear to be merely a result of a general retarda-
tion in growth rate. This explanation is difficult to accept, in view
of their reporting significantly increased embryonic lethality and
reductions in fetal weights at both dose levels and a reduction in
maternal weight gain at the 1.0 ml/kg level. In contrast, benzene
did not significantly increase the incidence of malformations at 0.3,
0.5 or 1 ml/kg/day, although benzene increased embryonic lethality
and maternal mortality, and decreased fetal weights at all three dose
levels (Nawrot and Staples 1979).
Other investigators have not found toluene to be teratogenic. In
a detailed investigation of teratogenicity, Hudak and Ungvary (1978)
exposed by inhalation pregnant CFY rats to toluene, xylene or benzene,
and pregnant CFL? mice to toluene. None of the solvents proved to be
teratogenic, although an increase in skeletal anomalies (extra ribs,
fused sternabrae) was observed with all 3 solvents. Benzene at 10CO
mg/m3 and toluene at 1500 mg/in3 caused a significant decrease in fetal
weights. At the highest exposure levels for toluene (1500 mg/m3), there
was 100 maternal mortalitv in mice and 20% in rats. At the next highest
exposure levels (500 mg/m3 for mice, 1000 mg/m^ for rats), there was no
maternal mortality. The exposure levels and other details of the experi-
mental results are presented in Tables 5-7 and 5-8.
The actual exposure levels in this study by Hudak and Ungvary (1973)
are considered high, estimated to be equivalent to ^360 mg/kg/day (which
is 0.100 liters/min x 60 min/hr x 24 hr/day 7 1000 1/m3 x 0.5 retention
x 1500 mg/m3 7 0.3 kg) at the 1500 aig/m3 exposure level for rats and
^280 mg/kg/day at the 500 mg/m3 exposure level for mice.
Roche and Hine (1968) concluded that neither benzene nor toluene
was teratogenic to the rat fetus or to the chick embryo (details of
exposure and results are not cited).
5.1.4 Additional Health Effects
Although the case reports summarized in Section 5.1.3.2 do not
clearly indicate overt toxicological manifestations to toluene as a
result of solvent abuse, they do suggest a tendency toward habituation,
which may have contributed to deterioration of mental health. A direcr
or synergistic effect of toluene in producing neurological deficits is
debatable. However, these effects, if caused by toluene, would only
result from long-term, high-level inhalation exposure.
5-21
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TABLE 5-7
LAYOUT OF THE EXPERIMENT AND SUMMAHI/ED DATA OK TUB KXPttlllMENTAL GIIOUPS OF UKNZKNE. TOLUENE AND XYLKNK TIIKATUI1
PIIKUNANT ANIMALS
l/i
N>
10
EstieibnentaJ groupi
Species
Hit*
_
Mice
•
Time of inhalation
Untreated control
D-l4Uayaof
prccnincy
84 h/
62.461
1.23
4A.HG1
204
22.641
6.08* •
4l.76t
2.43
411 20!
201
4
3.37
4.13
C.BO
7.78
6.30
6.72
2.21
6.04
6.10
—
8.20
Mean
Illlei
kUe
11.261
0.64
13.381
O.60
11.801
o.au
11.211
0.64
14.301
O.S7
11. lOt
0.60
13.301
0.66
lO.bul
1.30
il.OOl
0.74
—
lO.IBt
1.0(1
Mean
fetal
weight
(•>
3.831
0.02
3.761
0.02
3.381
O.02"
3.761
0.03
3.761
0.02
3.811
003
3.1111
0.03
3.311
0.08* •
I.O71
001
_
0.981
O.OI*»
Mean
plarenlnl
weight
Obit
O006
O47I
O.004
0.471 .
O.OOfi
0 161
OOOb
Obit
0.003
O.63t
OOOli
0.621
O.OOti
O.631
0.013
—
_
Wright
rctdnleil
ft!tnai!»c
<%1
20
fi.O
98.0f
17 3
bO
7 2
IliO
40.0t
0.6
_
27. Of
* In pel cent of Halting body weight.
In per cent of total linplanlilei.
c Per cent of living fclusci welglilng leu than 3.3 g (tali) or 0 0 g (inlce).
1 S.E.;»« V < 0.01 (l-te(t);t f < O.06.(M«nn Whitney II UU).
Source: llud&k and UngvAry (1978)
-------
TABLE 5-8
UATA OF THE FETUSES OP BENZENE. TOLUENE ANII XYLENE TIIKATKI> PHEGNANT ANIMALS
Experimental K>OU|II
R«ti Mica
Untreated Air Dcniene Toluene Xvlene Air Toluene Toluene Air Toluene
control Inhalellon Inhalation Inhalation Inhalation Inhalation Inhalation Inhalation Inhalation lululnllon
U-l4days 9-14 day* 9-14 daya 0-14 dayi 1-21 daya 1-21 daya l-8daya 8-13 day a 6-13 daya
24 h/day 24 h/day 24 h/day 24 h/day 8 li/daV 8 h/ilay 24 h/day 24 h/day 24 h/day
No. ulIllleraexamined 28 26 IB 19 2O 10 1O 0 14 11
No. olllve letuiea ' 31ft 348 220 213 28C 111 133 05 124 112
External malformation!
AKiiallib — — — — 2 — — ___
BrnclilmeUa -- -— ___ _ |_
Missing Ull — — - 2 — — — ___
No. uf fetuses dissected 160 170 110 ]1O 140 54 04 40 64 68
Internal mallumtallnne
Ol
10 ' Anophlhalinla — I — — — — — ___
W • MydrnecDlialua — — — — — __ 4 — —
Thynius hypopl. — — 1— ___ _ — —
llvd>onr|>lioroiia 316 6 4 26 1 (I 4 1 3
No. of AlUarlnxlaliied felulea 143 1150 108 1O2 143 67 89 42 6ft 64
Skeletal retardation slgni* — II 24T 6 17 — 17f 7f 3 I
Skeletal anomoliea
Fused sleniKUrae I 2 13t 7t 8t — — — — —
Extra rib* 2 — 8|- 22| t Of — — — • — —
Skeletal malformations
Pksura slernl — — — I — — ___
Ainalhla — — — — 2 — — ___
Mlulng vertebrae — — — 2 — — — ___
UriihlmeUu — — — — ___ _ |_
* Inrludlnf poorly ossified stemeurae. lilpartlle vertebra centra and klioilened 13lti ribs.
t I' < O.OA. tt <* < O.OI (Mann XVhltnry II leal).
Source: HudAk and Ungv&ry (1978)
-------
Of possible concern are the feto-toxic effects, especially,
reduced fetal weight gain and increased resorptions, which are esti-
mated to occur at absorbed dose levels of 360 mg/kg/day in rats and
280 lag/kg/day in mice (Hudak and Ungvary 1978). At a lower exposure
level — approximate absorbed dose 240 cg/kg/day in the rat — fetotoxic
effects were not statistically significantly increased compared with
unexposed control animals. This study may be relevant in view of
Syrovadko's (1977) report of more frequent fetal asphyxia and under-
weight babies in women occupationally-exposed to toluene although
other unidentified solvents may be involved. Further implications
of these results are discussed below.
5.1.5 Estimation of Human Risk
The limited human and animal data cited above do suggest a potential
fetotoxicity of toluene at high exposure levels. The potential should
be more carefully investigated in epidemological studies of occupational
exposures of pregnant women to toluene.
A no-effect human daily dose is calculated, assuming that 1000 mg/
m3 is a no-effect level in rats (Hudak and Ungvary 1978) and that an
effective dose in a 65-kilogram human female is from 1/2 to 1/6 the rag/kg
dose in the rat. The factor 1/2 is derived from data of Sato and Nakajizna
(1979), which indicates that clearance from the body is about twice as
fast in rats as in humans. The more conservative factor is derived from
the direct relationship between body surface area and metabolic rate
(MR) . Because surface area is proportional to body weight (bw) to the
2/3 power; i.e. :
it follows that:
MR [ratl/0.3 kg _
MR [human] /65 kg *
An exposure level of 1000 mg/m^ in a rat is estimated to be 240
mg/kg/day;
1000 mg/m3 x 0.100 1/min x 0.5 x 60 min/hr x 24 hr/day -,n
- - 1000 1/B3 x 0.3 kg - 24°
The human no-effect level is reduced by 1/2 to 1/6 to adjust for
metabolic rate differences so that 120-40 mg/kg/day or 7800-2600 ag/day/
body weight is the estimated no-effect dose level. These doses would be
absorbed at air exposure levels of 1600 to 540 mg/m^ in an 8-hour day.
An uncertainty factor of 100 is indicated based on guidelines cited
by the U.S. EPA (1979), which places acceptable daily ingestion (ADI)
at 78 to 26 nig/ day. The guidelines state that an uncertainty factor
5-24
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of 100 is to be used when chronic human data are not available, when
valid results in long-term feeding studies in one or more species are
available, and when no indication of carcinogenicity exists. Based
on the very low acute toxicity of toluene, its rapid metabolism to
non-toxic metabolites, and a presumption of a non-specific or general
CNS depression following inhalation exposures at the levels employed
in the reproductive study of Hudak and Ungvary (1978), an ADI of 78
to 26 mg/day is considered very conservative.
5.2 HUMAN EXPOSURE
5.2.1 Introduction
Monitoring data on toluene in the environment indicate a wide range
of toluene levels in the natural environment and in food. The fate
analyses also support the conclusion that toluene may occur in all en-
vironmental media. As discussed in the human effects section, it has
been determined that toluene can be absorbed by all three routes of
exposure—ingestion, inhalation, and dermal contact. The potential
absorption of toluene by these three routes has been considered in the
following analysis to estimate total daily absorbed dose.
Toluene concentrations in various media were estimated on a con-
servative basis in order to avoid underestimating the actual exposure
that could occur. These data were combined with data on rates of air,
water, and food Intake and/or duration of exposure to estimate the
amounts absorbed through each exposure route. Ideally, the absorption
of toluene would be analyzed with respect to subpopulation factors such
as age, weight, sex, breathing rates, food and water consumption,
commuting and working patterns, etc. For toluene, such detailed data
are not available and the variability and scarcity of the monitoring
data do not justify such a detailed analysis. Instead, in the analysis
below, total daily absorption of toluene has been approximated for two
broad population groups, based on their location with respect to major
toluene sources of emission.
Occupational exposure to toluene has been evaluated for each expo-
sure route (where appropriate) for a comparison with general population
exposure groups.
5.2.2 Exposure through Drinking Water and Food
Ingested toluene is presumed to be 100% absorbed. Humans may be
exposed to toluene through ingestion of contaminated drinking water,
either from surface or from ground water. The monitoring data on
toluene in ground water are insufficient either to indicate typical
levels or to document a range of concentrations. In addition, because
the populations exposed to contaminated ground water sources are
dispersed and unpredictable, it is not possible to ascribe very precise
numbers to these populations. However, the available data summarized
in Tables 4-2 and 4-3 suggest that most water supplies, whether of
5-25
-------
ground or surface origin, have levels of toluene below the detection
limit. Moreover, the U.S. EPA's Office of Drinking Water reports that
approxinataly 100 million people (about one-half the U.S. population)
receive surface waters in their homes. Thus, the remainder, who are
usually people living in communities with less than 60,000 people, are
receiving ground water either from public or private wells. Although
over 12 million private wells exist in the United States, the Office
of Drinking Water did consider that working people often consume more
water at their workplace than at home. Thus, regardless of the kind
of water supplied to their homes, most people are probably consuming
both ground and surface waters on the average (Coniglio, U.S. EPA,
Personal communication, 1980).
To estimate the exposure to toluene from drinking water supplies,
based on data given in Table 4-2, three approximations were utilized
to indicate the range of possible exposures. The first involved taking
the mean value of the observed concentrations at or above the detection
limit. This mean, 1.3 Ug/1, is thought to be representative of the
upper tail of the toluene concentration distribution. The second
approximation utilized all existing sampling data for surface water
supplies. A value of 0 was assigned to those reported as ND (not
detected) and 0.1 yg/1 to all reported as D—detected but not quanti-
fied. This analysis yields a mean of 0.15 ug/1. The third approxima-
tion assumes the worst case and all NDs were counted as 0.1 ug/1. This
third mean value was 0.24 ug/1, which is not markedly different from
the second value. The latter mean was used as a conservative estimate
of typical exposure to toluene through drinking water. At an average
water consumption of 2 liters per day, the estimated absorption of
toluene is typically about 0.5 ug/day but may average >3 ug/day for
some segments of the population. These results are given in Table 5-9.
Toluene may be ingested with foods. However, except for some data
on levels in fish tissues, no data are available on toluene levels in
foods. Per capita consumption of fish is taken from Stephan (1980) as
6.5 g/day. At an estimated mean concentration in fish tissue of 1 mg/kg
(see Section 4.3.3.1), approximately 6.5 ug/day of toluene may be in-
gested from fish alone.
5.2.3 Exposure through Inhalation
Sources of direct releases of toluene to the atmosphere include
the plants that isolate toluene, the industrial plants using toluene,
vehicular traffic, and gasoline distribution facilities. The emission
sources of concern are primarily automobiles (630 kkg/yr) and solvents
(370 kkg/yr, including paint, coating, adhesives, printing, Pharmaceu-
ticals etc.).
5-26
-------
The duration of exposure will vary with individual lifestyles,
location, local meterology, traffic volume and patterns, proximity
to user sites, and operating schedules at user sites. The labor force
in the vicinity of a source may be exposed 8 hr/day, while residences
in the area of a source may be exposed up to 24 hr/day. In the latter
case, emissions may be reduced or eliminated at the close of the working
day as a function of plant operation schedules. That is, pollutant
concentrations, which depend on the dispersion of emissions, will vary-
over time in any given location.
As an estimate of the absorption of toluene via inhalation, a
standard adult respiratory rate of 22.4 m-Vday has been used (1.2 m-*/
hour for 16 hours per day and 0.4 m-Vhour 8 hours a day while asleep).
About 50% of the toluene inhaled is retained and absorbed into the
blood (see 5.1.1.1). Therefore, absorption is approximated by computing
22.4 m-Vd x 0.5 x concentration (yg/sH).
The monitoring data, given in Table 4-9, do not indicate that
appreciably higher toluene levels may be found near either manufacture
or use sites than may be found within other urban areas. In fact, the
cities sampled by Pellizari (1979), which represent high chemical pro-
duction areas, have a similar average concentration to all the cities
shown in Table 4-9 (17 versus 19 ug/nr). In addition, Anderson and
coworkers (1980) performed dispersion modeling that indicated maximum
levels of <25 mg/m^ for exposure to specific point sources. The dis-
persion analyses for large (50 kkg/yr) sources and for a more typicallv
sized (20 kkg/yr) source yielded levels of 30 and 13 pg/m for a 20-meter
stack at a distance of 1000 meters. These results agree with the state-
ment of Suta (1980): "...concentrations of 0.001 to 0.2 ppb (0.004-0.75
ug/ar) near production plants are small compared to normal urban back-
ground concentrations, which may average more than 10 ppb (37.7 -jg/m^)
in some locations."
The average urban air concentration—of-
-------
TABLE 5-9. ESTIMATED HUMAN EXPOSURE TO TOLUENE BY ALL ROUTES
Exposure
Route/Scenario
INGESTION
Water
- All surface supply
data
- High end of distri-
bution of surface
water supplies
Food
- Fish tissues
INHALATION*1
- Urban areas
- Renote areas
- Use of gasoline
stations
- Occupational:at
OSHA standard
- Cigarette
PERCUTANEOUS
- Occupational—
2 hands unprotected
- Consumer Products
Amount Con-
Concentration3 suased or In-
Daily Absorption
Tvpical Range haled Daily
(Pg/l)
0.24 NDrl9
1.3 0.1-19
(Db
2
2
Typical Range
(ug/day)
n.s ?-ia
3 ?-38
(og/kg)
(kg)C
1.0 ND-35
19 / 0.15-283
-3/ ND-3.8
860 100-5400
754,000
(yg/cigarette)
100
(mg/hr)
•v, 40
2.0
0.0065
22.4
22.4
0.024 m3/
.02 hrs.
9.6«
(packs)
1.56
(hrs)
0.08-0.5
0.08-0.5
6.5 ?-224
210 1.7-3,170
11 ?-43
10 1-65
3,600,000
1,560
3,200-20,1
yg/use
23-1*0
from Section 4.3, Monitoring Levels in the Environment.
bData from ICR? (1975).
CData from Stephan (1980).
Inhalation exposure estimates are calculated using a. 50% respiratory retention.
Data from ICRP (1975), for a 24-hour exposure, based on 1.3 ia3/hr during 16 hours
of waking and 0.4 mVhr for 8 hours of sleep.
Inhaled amount for 8 hours at 1.2 nrvhr.
5-28
-------
Similarly, these authors identified a subpopulation of 2.3 million
exposed to levels between 0.1 and 100 ug/m^ from general point sources
and a third group of 192 million, which may include members of the
first two groups, exposed to area sources at levels from 5-100 yg/m .
No data were available on toluene concentrations in the immediate
vicinity of gasoline marketing pumps and stations. However, evaporative
emissions from gasoline contain about 1.37, toluene (see page A-4) and
about 1.2% benzene (Arthur D. Little, Inc. 1981). Using the ratio of
toluene to benzene in gasoline evaporate (approximately 1), and the
monitoring data for benzene at gasoline service stations, an estimate
for toluene levels in the same situation can be made. Battelle (1979)
reports an average level for benzene of 860 yg/m in customer areas;
Hartle and Young (1976) report a range of 100-5400 yg/nr*. Therefore,
an estimated average toluene level of 860 pg/m^ and a range of 100-5400
ug/m' was assumed. It has been assumed that the average driver spends
10 minutes once a week ac the gas station for an average daily exposure
of 0.02 hours. The estimated daily absorption of toluene from use of
gasoline stations then is 10 ug and may range from 1 vg to 64 ug.
Occupational exposures to toluene by inhalation are analyzed at the
OSHA standard. The standard established by OSHA is 854 mg/m3 (200 ppm)
as a time-weighted-average for the 8-hour work day (OSHA 1978). NIOSH
(1973) estimated that about 4.8 million workers were exposed to toluene.
At this concentration, a worker can absorb about 1,800,000 ug/day or
1.8 grams.
It has also been determined that cigarette smoking adds to the
amount of toluene inhaled and also increases levels in the surrounding
air. According to NRC (1980), the average toluene exposure is 0.1 nig/
cigarette. Based on data from the 1979 report from the U.S. Surgeon
General, the "average" smoker (1.56 packs/day, Richmond 1981) would
be exposed to 3.1 mg/day although absorption is 1560 yg/day. The U.S.
Surgeon General also reported a total of 54 million smokers in the
United States in 1978 for all age groups. In addition ^Young (1978)
has stated that "unknowing inhalation" in the home can occur from the
use of paint strippers, carburetor cleaners, denatured alcohol, rubber
cement, and arts and crafts supplies. These sources have not been
documented, and exposures are assumed to be infrequent as well as dilute.
5.2.4 Percutaneous Exposure
5.2.4.1 Occupational Exposure
In a study of absorption of toluene through the skin, Sata and
Nakajima (1978) immersed one hand of 5 male subjects in pure toluene
for 30 minutes and monitored blood levels of toluene. The peak concen-
tration of 18 yg/1 was observed within 10 minutes after exposure ceased
and decreased over the next few hours. It was calculated in the pre-
vious section that the absorption rate through the skin of one hand
was ^20 mg/hour for pure toluene.
5-29
-------
Although the OSHA (1973) standards require all workers handling
toluene directly to wear gloves, it is conceivable that, in the work-
place and in research laboratories, short-tern exposure would take
place across the bare skin of both hands. Using the calculated absorp-
tion rate and exposure durations, ranging from 5-30 minutes per use,
the absorption of toluene across the skin is estimated to be between
3.2 and 20 mg/use, for unprotected hands. Sato and Nakajima (197S)
concluded their paper with the following "...toluene would rarely be
absorbed through the human skin in toxic quantities during normal
industrial use."
5.2.4.2 Consumer Products
The majority of solvents, paint removers, paints and other sub-
stances used in the home would contain only small amounts of toluene
as a component or contaminant. Assuming a scenario similar to the
occupational scenario described above, which involved a 5% toluene so-
lution and a 5-30 minute exposure duration, the exposure is:
20 mg/hr x 2 (hands) x 0.05 x (0.08-0.5) hr • 0.21 mg/use.
For the purposes of this report, a use rate of once per week was
assumed,' resulting in an estimated average daily exposure 23-140 yg.
5.2.5 Total Exposure Scenarios and Conclusions
The results of the exposure estimates summarized in Table 5-9 have
been used to derive two comprehensive, total exposure scenarios for all
routes (Table 5-10). These scenarios are not meant to define actual
exposures for a specific individual but to typify likely levels in
probable situations for the identifiable subpopulations.
Scenario A considers exposures to about 150,000,000 people living
in urban areas (74% of the 1980 census population) who drink predom-
inantly surface waters (110 million people drink surface water, usually
supplied to urban areas with more than 60,000 people), breathe urban
air, and consume 6.5 g fish per day. This subpopulation also uses
products containing toluene for about 1/2 hr/week. The total typical
daily dose Is about 370 ug. If the individual smokes cigarettes, the
daily dose is about 1800 wg.
Scenario B considers that population living in the rural or remote
areas of the country, numbering in 1970 about 54,000,000 people (or 26%
of the 1970 census). This subpopulation is supplied nearly 100% with
ground water for drinking purposes; however, in the absence of sufficient
monitoring data, the surface water value was used. For the purposes of
example, it is assumed that this subpopulation uses products containing
toluene for about 5 minutes per week. If the contamination of wells is
considered, from the disposal of wastes, it is possible that this may
be a problem in the more densely populated areas that are near the
sources rather than in rural areas. Total typical daily exposure fcr
this scenario is 51 ug or 1600 ug if smoking is involved.
5-30
-------
To provide a contrast with these two ambient exposure scenarios,
potential industrial exposures of employees producing and utilizing
toluene ware calculated. If exposure occurs at the occupational stan-
dard, the employee can add 3500 Gig/day to baseline (food and water and
nonoccupational inhalation) exposure. If percutaneous exposure also
occurs, an additional exposure up to 20 sg/use is possible.
5.2.6 Summary
In conclusion, the two nonoccupational, ambient exposure scenarios
had total exposures of about 51-370 yg/day, excluding smoking. The
addition of smoking increased exposure by a factor of 8 to 60. Compared
with the potential occupational exposure, typical exposure to toluene
is three to four orders of magnitude less.
5-31
-------
TABLE 5-10. TOTAL HUMAN EXPOSURE SCENARIOS FOR TOLUENE
Route
7, of 1970 population
Exposure by Scenario
A 3.
_74 2£
(ug/day) (yg/day)
Ingest ion
Water
Food
Inhalation
Baseline
Gas Station Use
Cigarettes3
0.5
6.5
210
10
1,560
0.5
6.5
11
10
1,560
Percutaneous
Consumer products
140
23
Total-excluding cigarettes
Total-including cigarettes"
370
1,900
51
1,600
a
Cigarette smoking involved 54 million individuals in 1978.
5-32
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REFERENCES
Anderson, G.E.; Liu, C.S.; Holaan, H.H.; Killus, J.P. Human exposure
to atmospheric concentrations of selected chemicals. Research Triangle
Park, NC: U.S. Environmental Protection Agency; 1980.
Angerer, J. Occupational chronic exposure to organic solvents. VII.
Metabolism of toluene in man. Int. Arch. Occup. Environ. Health.
43:63-67; 1979.
Arthur D. Little, Inc. An exposure and risk assessment for benzene.
Final draft. Washington, DC: U.S. Environmental Protection Agency;
1981.
Bakke, O.M.; Scheline, R.R. Hydroxylation of aromatic hydrocarbons
in the rat. Toxicol. Appl. Pharnacol. 16:691-700; 1970.
Banfer, W. Studies on the effect of pure toluene on the blood picture
of photogravure printers and helper workers. Zentralbl. Arbeitsmed.
11:35; 1961. (As cited in NIOSH 1973)
Battelie Columbus Labs. Environmental monitoring of benzene. Columbus,
OH: Batelle Columbus Labs; 1979.
Bass, M. Sudden sniffing death. Jour. Am. Med. Assoc. 212:2075; 1970.
(As cited in U.S. EPA 1980a)
Boor, J.W.; Hurtig, H.I. Persistent cerebellar ataxi after exposure to
toluene. Ann. Neurol. 2:440-442; 1977.
Capellini, A.; Alessio, L. The urinary excretion of hippuric acid in
workers exposed to toluene. Med. Lavoro 62:196-201; 1971. (As cited
in NIOSH 1973)
Carpenter, C.P.; Geary, P.L.J Myers, R.C.; Machreiner, D.J.; Sullivan,
L.J.; King, J.M. Petroleum hydrocarbon tcxicity studies. XIII. Animal
and human response to vapors of toluene concentrate. Toxicol. Appl.
Pharmacol. 36:473-490; 1976.
Dean, B.J. Genetic toxicology of benzene, toluene, xylenes and phenols.
Mutat. Res. 47:75-97; 1978.
Diem, K.; Lentner, C. eds. Scientific Tables 7th edition Ciba Geigy
Limited, Basle, Switzerland; 528; 1971.
5-33
-------
Dobrokhotov, V.B.; Enikeev, M.I. Mutagenic effect of benzene, toluene,
and a mixture of these hydrocarbons in a chronic experiment. Gig.
Sanit. 1:32-34; 1977.
Forni, A.; Pacifico, E.; Limonta, A. Chromosome studies in workers
exposed to benzene or toluene or both. Arch. Environ. Health 22:
373-378; 1971.
Frei, J.V.; Kingsley, W.F. Observations on chemically induced tumors
of mouse epidermis. J. Natl. Cancer Inst. 41:1307-1313; 1968.
Friborska, A. Some cytochemical findings in the peripheral white blood
cells in workers exposed to toluene. Folia Haematol. Leipzig 99:233-237;
1973.
Gibson, J.E. Chemical Industry Institute of Toxicology—Two-year vapor
inhalation toxicity study with toluene in Fischer-344 albino rats: .
18-month status summary. Personal communication; 1979. (As cited
in U.S. EPA 1980a)
Goto, I.; Matsumura, M.; Inoue, N.; Murai, Y.; Shida, K.; Santa, T.;
Kuroiwa, Y. Toxic polyneuropathy due to glue sniffing. Jour. Neurol.
Neurosurg. Psychiatry 37:848-853; 1974.
Goldstein, A.; Aronow, L.; Kalman, S.M. Principles of the drug action.
2nd edition. New York. John Wiley & Sons; 1974; 262-264.
Grabski, D.A. Toluene sniffing producing cerebellar degeneration. Am.
Jour. Psychiatry 118:461-462; 1961.
Greenburg, L.; Mayers, M.R.; Heiman, H.; Moskowitz, S. The effects of
exposure to toluene in industry. Jour. Am. Med. Assoc. 118:573-584;
1942.
Hartle, R.; Young, R. Occupational exposure to benzene at service stations.
Cincinnati, OK: Division of Surveillance Hazard Evaluations and Field
Studies, National Institute for Occupational Safety and Health; 1976.
Horiguchi, S. et al. Studies on industrial toluene poisoning, Part IV.
Effects of toluene on wheel-turning activity and peripheral blood
findings in mice. Sumitomo Sangyo Eisei 12:81; 1976. (As cited in
U.S. EPA 1980a)
Hudak, A.; Ungvary, G. Embryotoxic effects of benzene and its methyl
derivatives: toluene and xylene. Toxicology 11:55-63; 1978.
Ikeda, M. Reciprocal metabolic inhibition of toluene and trichloro-
ethylene in vivo and in vitro. Int. Arch. Arbeitsmed. 33:125-130; 1974.
5-34
-------
Ikeda, T.; Miyake, H. Decreased learning in rats following repeated
exposure to toluene: Preliminary report. Toxicol. Letters 1:235-239;
1973.
Ikeda, M.; Ohtsuji, K. Phenobarbital-induced protection against
toxicity of toluene and benzene in the rat. Toxicol. Aopl. Phannacol.
20:30-43; 1971.
Ikeda, M.; Ohtsuji, H.; Imamura, T. In vivo suppression of benzene and
styrene oxidation by co-administered toluene in rats and effects of
phenobarbital. Xenobiotica 2:101-106; 1972.
International Commission on Radiological Protection (ICRP). Task force
on reference nan. New York, NY: Pergammon Press; 1975.
Jenkins, L.J., Jr.; Jones, R.A.; Siegel, J. Long-term inhalation screen-
ing studies of benzene, toluene, o-xylene, and cumene on experimental
animals. Toxicol. Appl. Pharmacol. 16:818-823; 1970.
JR3, Inc. Level II materials'balance for benzene. McLean, VA: JRB,
Inc.; 1980.
Keane, J.R.. Toluene optic neuropathy. Ann. Neurol. 4:390; 1978.
Kelly, T.W. Prolonged cerebellar dysfunction associated with paint-
sniffing. Pediatrics 56:605-606; 1975.
Knox, J.W.; Nelson, J.R. Permanent encephalopathy from toluene inhala-
tion. New England Jour. Med. 275:1494-1496; 1966. '
Konietzko, H.; Keilbac,, J.; Drysch, K. Cumulative effects of daily tol-
uene exposure. Int. Arch. Occup. Environ. Health 46:53-58; 1980.
Lehnert, G.; Ladendorf, R.D.; Szadkowski, D. The relevance of the
accumulation of organic solvents for the organization of screening tests
in Occupational Medicine. Results of toxicological analyses of more than
6000 samples. Int. Arch. Occup. Environ. Health 41:95-102; 1978.
Lyapkalo, A.A. Genetic activity of benzene and toluene. Gig. Tr. Prof.
Zabol. 17:24; 1973. (As cited in Dean 1978)
Matsushita, T., et al. Henatological and neuro-inuscular response of
workers exposed to low concentration of toluene vapor. Ind. Health
13:115; 1975. (As cited in U.S. EPA 1980a).
Nawrot, P.S. ; Staples, R.E. Eiabryofetal toxicity and teratogenicity of
benzene and toluene in the mouse. Teratology 19:41A; 1979.
5-35
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National Institute for Occupational Safety and Health (NIOSH).
Criteria for a recommended standard ... occupational exposure to
toluene. HEW publication No. HSM 73-11023. 'l'.S. Government
Printing Office. Washington, DC; 1973.
National Research Council (NRC). The alkyl benzenes. Washington, DC:
National Academy Press; 1980.
Occupational Safety and Health Administration CCSHA). OSHA Safety and '
Health Standard- 29 CFR 1910. U.S. Department of Labor, Washington,
D.C.; 1978.
Ogata, M.; Tomokuni, K.; Takatsuka, Y. Urinary excretion of hippuric
acid and m- or p-methylhippuric acid in the urine of persons exposed
to vapors of toluene and m- or p-xylene as a test of exposure. Sr.
Jour. Ind. Med. 27:43-50; 1970.
Papper, E.W.jKitz, E. Uptake and distribution of anesthetic agents.
New York, NY: McGraw Hill; 1963.
Pellizari, E.D. Information on the characteristics of ambient organic
vapors in areas of high chemical production. Research Triangle Park,
NC: Research Triangle Institute; 1979. (As cited in Suta 1930)
Pfaffli, P.; Savolainen, H.; Kalliornaki, P.L.; Kalliokoski, P.
Urinary o-cresol in toluene exposure. Scadd. J. Work Environ, and
Health 5:286-289; 1979.
Powars, D. Aplastic anemia secondary to glue sniffing. New England
Jour. Med. 273:700-702; 1965.
Pyykko, K.; Tahti, H.; Vapaatulo, H. Toluene concentrations in various
tissues of rats after inhalation and oral administration. Arch. Toxicol.
38:169-176; 1977.
Rhudy, R.L.; Lindberg, D.C.; Goode, J.W.; Sullivan, D.J.; Gralla, E.J.
Ninety-day subacute inhalation study with toluene in albino rats.
Toxicol. Appl. Pharmacol. 45:284-285; 1978.
Richmond, T.B. The changing cigarette. Preface to the 1980 report of
the Surgeon General, Washington, DC: Office of the Surgeon General,
U.S. Department of Health, Education, and Welfare; 1981.
Riihimaki, V. Conjugation and urinary excretion of toluene and m-xylene
metabolites in a man. Stand. J. Work Environ, and Health 5:135-142;
1979.
Riihimaki, V.; Pfaffli, P. Percutaneous absorption of solvent vapors
in man. SF-00290 29, Scand. J. Work Environ. Health 4(l):73-85; 1978.
Roche, S.M.; Hine, C.H. The teratogenicity of some industrial chemicals.
Toxicol. Appl. Pharmacol. 12:327; 1968.
5-36
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Sato, A.; Nakajima, T. Differences following skin or inhalation exposure
in the absorption and excretion kinetics of trichloroethylene and tolu-
ene. Br. J. Ind. Med. 35(l):43-^9; 1978.
Sato, A.; Nakajima, T. Dose-dependent netabolic interaction between
benzene and toluene in vivo and in vitro. Toxicol. Appl. Phannaccl.
48:249-256; 1979.
Sato, A.; Nakajima, I.; Fujiwara, Y.; Hirosawa, K. Phannacokinetics of
benzene and toluene. Int. Arch. Arbeitsmed. 33:169-182; 1974.
Shirabe, T. Isuda, T.; Terao, A.; Araki, S. Toxic polyneuropathy due
to glue-sniffing. Report of two cases with light and electron-
microscopic study of the peripheral nerves and muscles. Jour. Neurol.
Sci. 21:101-113; 1974.
Stephan, C.E. Memorandum to J. Starr, U.S. Environmental Protection
Agency; 1980. (As cited in U.S. EPA 1980a)
Suta, B. Non-occupational exposures to alkylbenzenes from their use as
solvents. Washington, DC: Office of Research and Development, U.S.
Environmental Protection Agency; 1980.
Suzuki, T.; Shimbo, S.; Nishitani, H. Muscular atrophy due to glue
sniffing. Int. Arch. Arbeitsmed. 33:115-123; 1974.
Syrovadko, O.N. Working conditions and health status of women handling
organosiliceous varnishes containing toluene. Gig. Tr. Prof. Zabol.
12:115; 1977. (As cited in U.S. EPA 1980a).
Takeuchi, Y. Experimental studies on the toluene poisoning—chiefly
on the findings of peripheral blood and adrenal gland. Ind. Health
7:31-45; 1969.
Tarsh, M.J. Schizophreniform psychosis caused by sniffing toluene. J.
Soc. Occup. Med. 29:131-133; 1979.
Taylor, G.J.; Harris, W.S. Glue sniffing causes heart block in mice.
Science 170:866-868; 1970.
Towfighi, J.; Gonatas, N.K.; Pleasure, D.; Cooper, H.S.; McCree, L.
Glue sniffer's neuropathy. Neurology 26:238-243; 1976.
U.S. Environmental Protection Agency (U.S. EPA). Water quality criteria.
Appendix C. Guidelines and methodology used in the preparation of health
effect assessment depths of the consent decree water criteria documents.
Part B non-stochastic effects. Federal Register 44(52):15980; 1979.
U.S. Environmental Agency (U.S. EPA). Ambient water quality criteria
for toluene. EPA 440/5-80-075. Washington, DC: Office of Water
Regulations and StandardsjCriteria and Standards Division; U.S.
Environmental Protection Agency; 1980a.
5-37
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U.S. Environmental Protection Agency (U.S. EPA). Problem oriented report.
Carcinogen Assessment Group. Washington, DC: Office of Health and
Environmental Assessment, Office of Research and Development, United
States Environmental Protection Agency; 1980b.
Van Doom, R.; Bos, R.?.; Brouns, R.M.E.; Leijiekkers, C.M.; Henderson,
P.I. Effect of toluene and xylenes on liver sluthathione and their
urinary excretion as mercapturic acids in the rat. Inst. Pharmaco.
and Toxicol., University of Nijmesen, Nijinesen, Netherlands. Arch.
Toxicol. 43(4):293-304; 1980.
Veulemans, H. Masschelain, R. Experimental human exposure to toluene.
I. Factors influencing the individual respiratory uptake and elimination.
Int. Arch. Occup. Environ. Health 42(2):91-103; 1978a.
Veulemans, H.; Masschelein, R. Experimental human exposure to toluene
II. Toluene in venous blood during and after exposure. Int. Arch.
Occup. Environ. Health ^2:105-117; 1978b.
Veulemans, H.; Masschelein, R. Experimental human exposure to toluene
III. Urinary hippuric acid excretion as a measure of individual solvent
uptake. Int. Arch. Occup. Environ. Health 43:53-62; 1979.
Weisenberger, 3.L. Toluene habituation. Jour. Occup. Med. 19:569-570;
1977.
Wilczok, T.; Bieniek, G. Urinary hippuric acid concentration after
occupational exposure to toluene. Brit. J. Ind. Med. 35:330-334; 1978.
Woiwode, W.; Wodarz, R.; Drysch, K.; Weichardt, H. Metabolism of tolu-
ene in man: gas chrcmatographic determination of o-, m-, and p-cresol
in urine. Arch. Toxicol. 43:93-98; 1979.
Wolf, M.A. «£ _al. lexicological studies of certain alkylaced benzenes
and benzene. Arch. Ind. Health 14:387; 1956. (As cited in U.S. EPA
1980a)
Young, R.J. Benzene in consumer products. Sci. 199:248; 1978.
Yushkevich, L.B.; Malysheva, M.V. Study of the bone marrow as an index
of experimentally-induced poisoning with chemical substances (such as
benzene and its hotnologs). Sanit. - Toksikol. Metody Issled. Gig:
36; 1975. (As cited in U.S. EPA 1980a).
5-38
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6.0 BIOTIC EFFECTS AND EXPOSURE
6.1. BIOTIC EFFECTS
6.1.1 Introduction
This section provides information on the exposure levels of toluene
that cause mortality or disrupt physiologic functions and processes
in aquatic organisms. Fairly extensive data exist for both marine
and freshwater organisms, including fish, invertebrates, plankton,
algae, and microorganisms. Toxicity data for these organisms are
presented in tables in this chapter.
Toluene is one of the major components of the water-soluble fraction
of petroleum. Under test conditions, it reacts as a highly volatile
compound with a half-life of approximately 30.6 minutes (Buikeraa and
Hendricks 1980). The half-life in river water has been calculated to
be 4.9 hours (see Chapter 4.0). This difference indicates that vclaci-
zation is substantially more rapid under laboratory conditions, so that
the concentrations derived in toxicity tests may only approximate what
might actually occur in the natural environment. Thus, static, un-
measured toxicity tests overestimate the toxicity, due to losses of
toluene due to volatization from the test water.
Further, use of laboratory data to predict in situ effects is com-
plicated by variations between laboratory and actual environmental condi-
tions. These may include environmental factors affecting bioavailability
of toluene in actual aquatic systems, such as adsorption to sediments
and suspended particulate matter.
6.1.2 Mechanisms of Toxicitv
Investigation of several alkyl benzenes, including toluene, suggests
that toxicity might result from soiubilization of fats from the gill
membranes of fish, with consequent increases in permeability and uptake
of ions from the hypertonic environment (National Research Council 1980).
The exact mechanisms of toxicity are not fully understood; however,
based on changes in the blood chemistry of young coho salmon, Morrow
and coworkers.(1975) suggested that narcosis was a result of changes
in gill permeability causing ionic imbalance and internal C02 poisoning.
These effects result in the loss of equilibrium and weakened muscle
movement. These observations were made for several crude oil compon-
ents, including toluene.
Toluene acts, as do other aromatic hydrocarbons, as a neurotoxin.
At high concentrations, fish sequentially go through phases of restless-
ness, "coughing" or backflushing of water over the gills, increased
irritability, loss of equilibrium, paralysis, and death (Morrow et al.
1975). In addition, heart rate decreased and heart beat became irregular
6-1
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in fish fry exposed to toluene. Toluene was found to have teratogenic
effects on Japanese medaka fry. The concentrations that caused devel-
opmental deformities ranged from 41 to 163 mg/1 (Buikena and Hendricks
1930), which is higher than many of the LC5o's for adult freshwater fish.
6.1.3 Freshwater Organisms
Seven fish species have been tested for acute toxicity to toluene.
The LC5o's ranged from 12.7 and 24.0 mg/1 for bluegill up to 1180 mg/1
for the mosquito fish (Gambusia affinis) . Various authors derived the
LCso's in Table 6-1 using different methods. However, the majority
reported I^Q'S <60 mg/1.
Pickering and Henderson (1966) conducted tests on four freshwater
fish species, under static conditions, in soft water (20 mg/1 CaCC^) at
pH 7.5. The results of similar tests conducted in hard water (300 mg/1
CaCO-i) showed that hardness had little effect on toxicity. In the
static tests, most of the toxic effects apparently occurred during the
first 24 hours, because 96-hour LC^Q'S were similar to those measured
at 24 hours. Actual concentrations during the test period were not
measured. Because it was assumed that much of the toluene volatilized
during testing, the LCgg values reported are probably high. Studies
with goldfish (Carassius auratus) support this conclusion as well. In
these tests, considerably lower 96-hour LC5Q values were found for
toluene in a flow-through bioassay with measured concentrations of the
test compound (Brenniman Bt_ al. 1976) .
The only freshwater invertebrate data available were for Daphnia
magna. The LC^Q value for this species (313 mg/1), suggests that more
it may be more resistant than the fish species tested. Mo chronic data
were available for freshwater biota of any species.
6.1.4 Marine Organisms
Few studies have been conducted with saltwater fish. Beaville and
Korn (1977) found toluene to be lethal to striped bass (Morone saxatilis)
at 7.3 mg/1 (Table 6-2). Sheepshead minnows (Cyprinodon variegatus) had
a 96-hour LC50 of 277-485 mg/1 (U.S. EPA 1978), which demonstrates con-
siderably more resistance than shown by other species on which data are
available. Gambusia, a hardy freshwater species, also demonstrates a
similar resistance pattern, although it was tested in turbid water. An
embryo larval test of sheepshead minnows indicated a chronic value of
5 mg/1, which caused adverse effects on hatching and survival (U.S.
EPA 1978) (Table 6-3).
Acute toxicity tests have been conducted on several invertebrates,
including four shrimp species, a copepod, and the crab Cancer magister.
6-2
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TABLE 6-1. ACUTE TOXICITY OF TOLUENE TO FRESHWATER FISH
Soecies
Goldfish
Carassius auratus
Goldfish
Carassius auratus
Fathead minnow
Fimephales promelas
Fathead minnow
Piaephales promelas
Guppy
Foecilia reticulatus
Bluegill
Leoomis macrochirus
Bluegill
Lepomis aacrochirus
Mosquito Fish
Gambusia affinis
Lebistes reticulatus
Bioassav
Method3
FT
S
S
S
S
S
S
S
S
LC50
(mgTD
22.8
57.7
34.3
42.3
59.3
24.0
12.7
1180. Oa
60.9
Fink Salmon
Oncorhynchus gorbuscha
8.09'
Reference
Brenninan et al. (1976)
Pickering and Henderson (1966)
Pickering and Henderson (1966)
Pickering and Henderson (1966)
Pickering and Henderson (1966)
Pickering and Henderson (1966)
U.S. EPA (1978)
Wallen et al. (1957)
Pickering and Henderson (1966)
Korn et al. (1977)
Note:
S= Static, FT= flow-through
a
Tested in turbit water.
This value derived in tests on (examining) the interaction between temperature
and toluene toxicitv.
6-3
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TABLE 6-2. ACUTE TOXICITY OF TOLUENE TO MARINE FISH
Soecies
Coho Salmon
Orcorhynchus kisutch
Striped Bass
Mb rone saxatilis
Sheepshead Minnow
Cygrinodon variegatus
Tlae
(hrs)
96
96
96
(mg/1)
6.3
>277.G-
<485.0
Reference
10.0-50.0 Morrow et al. (1975)
Benville and Korn (1977)
U.S. EPA (1978)
TABLE 6-3. CHRONIC TOXICITY OF TOLUENE TO MARINE FISH
Organism Test
Sheepshead Minnow Embryo-
Cygrinodori variegatus larval
Limits
(mg/1)
2.8-6.7
Chronic Value
(mg/1)
2.1
Source: U.S. EPA (1978)
6-4
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Values for these organims ranged from 3.7 ag/1 for the Bay shrimp,
Crago franciscorum. to 170.0 mg/1 for Cancer magister. Most of the
Invertebrate toxicity values ranged from 10 to 75 mg/1 (Table 6-4).
All of these concentrations were derived from static toxicity tests.
6.1.5 Phytctoxicity
Photosynthetic organisms, such as algae and marine phytoplankton,
are important primary producers in freshwater and marine ecosystems.
Several studies have been conducted to determine the effects of toluene
on these organisms. It is believed that the effects of toluene on
plant cells are biophysical rather than biochemical, and the effects
include disrupting cell membrane structure and changing internal
morphology of the cells, as in the case of fish gill tissue (National
Research Council 1980). Table 6-5 presents toxicity data on fresh-
water plants. Toxicity data for marine plants are presented in Table
6-6. Inhibitory effects (growth reduction, photosynthesis) in six
species occurred in the range of 8.0-100 ag/1. No effects on one
species tested (Skeletonema costatus) were observed at concentrations
up to 433 mg/1.
6.1.6 Factors Affecting the Toxicity of Toluene
Few empirical data exist on the environmental factors that may
affect the toxicity of toluene to biota. However, based on studies with
benzene, some generalizations can be made. Because of the high volatility
of toluene, any factor that affects its persistence in water will ulti-
mately influence its toxicity. Studies of temperature interactions
and benzene toxicity indicate that at lower test temperatures, organisms
were more tolerant (Potera 1975). The effects of temperature on toluene
tcxicity were studied for two coldwater marine species, pink salmon and
shrimp (Eualus spp). These data are inconclusive (Table 6-71 as toxicitv
increased with increasing temperature in shrimp, and little temperature
difference among toxicity levels at different temperatures was noted
in salmon (Korn et_ al. 1977).
Other factors found to influence benzene toxicity and potentially
that of toluene, include size and life stage of the organism, salinity,
and synergistic effects of other compounds (Buikema and Hendricks 1980).
Water hardness has been found to have little effect on toxicity in
studies with freshwater fish (Pickering and Henderson 1966).
6.1.7 Summary
According to the literature reviewed, the lowest concentration at
which effects of toluene have been observed in aquatic organisms is 3.7
mg/1, the LC5Q for the marine shrimp, Crago franciscorum. Invertebrates
tended to be more sensitive than other fish and algal species tested,
with the exception of striped bass, Morone saxatilis. which was affected
by a relatively low (LC5Q, 6.3 rng/1) concentration of toluene. The most
6-5
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TABLE 6-4. ACUTE TOXICITY OF TOLUENE TO
MARINE INVERTEBRATES (STATIC TESTS)
Scecies
Copepod
Nitocra spinipes
Mysid Shrimp
Mvsidoosis bahia
Bay Shrimp
Craeo franc iscorum
Grass Shrimp
Palaeraonetes pugio
Grass Shrimp (Adult)
Palaemonetes pueio
Grass Shrimp (Larva)
Palaemonetes pugio
Brine Shrisp
Artemia salina
Crab
Cancer magister
Tine
(hrs)
24
96
96
96
24
24
24
48
96
EC50 or LC50
(mg/1)
24.2-74.2
56.3
3.7
9.5
17.2-38.1
25.8-30.6
33
170.0
28.0
Reference
Potera (1975)
U.S. EPA (1978)
Benville and Kom (1977)
Taten (1975)
Potera (1975)
Potera (1975)
Price et al. (1974)
Caldwell (1976)
6-6
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TAHLE 6-5. EPFRCTS OK TOLUENE ON PRES1IUATEK PI.ANTS
Organism
Alga
Clilorella vulgar Is
Effects
24-hour
cell numbers
Concentration
mg/1
245.0
Reference
Knuss and Hutchlnson (1975)
Alga
SeJenastrum
capricornutum
96-hour ECso for
chlorophyll j»
production
>433.0
U.S. EPA (1978)
Alga
Selonastrum
cnpr Lcornutum
96-hour ECso for
cell numbers
>433.0
U.S. EPA (1978)
-------
TARLE 6-6. Kl'PECTS OK TOLUKNIi ON MAKINK VIANTS
Organism
Kffcrts
Concent ratJon
Keferenee
Kelp
Macrocystts pyrifera
Alga
Aiuplildtnlum carter!
Alga
Chi ore] la sp.
Alga
o> Clilorclla sp.
00
A3 ga
Cricosplmera carterae
Alga
Uunaliella tertiolecta
Alga
Skcletonoma cos tat urn
Alga
Skeletonema costatum
Alga
Skcletoricma costatum
mg/1
Photosynthesis 10.0
Growth 100.0
Photosynthesis 34.0
respiration
Photosynthesis 85.0
respJ ration
Growth JOO.O
Growth 100.0
Growth 8.0
96-hour EG'so for > 4 33.0
chlorophyll a
production
96-hour ECso for >
-------
TABLE 6-7. INTERACTION OF TEMPERATURE AND TOLUENE
ON MARINE D1VERTEBRATE
96-hour TL>i (mg/1)
Species 4eC 8°C 12°C
Oncorhynchus gorbuscha 6.41 7.63 8.09
Eualus spp. 21.4 20.2 14.7
Source: Korn et al. (1977).
6-9
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sensitive freshwater fish species tested was the bluegill (LC^Q, 12.7
mg/1). The levels of acute toxic effects to fish ranged from 6.3 to
60.9 ng/1.
Acute effects for invertebrates ranged from 3.7 (bay shrintp) to
170.0 ag/1 (crab Cancer aagister, 48-hour LCso). Most of the inver-
tebrate acute concentrations were from 10 to 80 ng/1. Algae, both
freshwater and marine, were quite resistant to toluene, as no acute
effects (reduction in cell numbers and chlorophyll a_ production) were
observed at <245.0 mg/1, although effects on growth were observed at
concentrations as low as 8 mg/1. The only chronic study available was
on the sheepshead minnow, which had a reported chronic value of 2.2 ng/1.
The U.S. EPA (1980a) has not set water quality criteria for toluene
to protect aquatic life. They have concluded that acute toxicity to
freshwater aquatic life may occur at concentrations as low as 17.5 mg/1.
Acute and chronic toxicity to saltwater aquatic life may occur at con-
centrations as low as 6.3 and 5 mg/1, respectively. In all cases, it
was concluded that toxicity would occur at lower concentrations if more
sensitive species were tested.
In summary, however it is useful to show concentration ranges for
which certain effects are seen in the laboratory. However, these ranges
are not rigidly defined and may overlap as a result of differences among
life stages, species, test methodologies, and environmental variables.
Test ranges include:
• 1.0-10.0 mg/1 Threshold of toxic effects of toluene to
aquatic biota, including acute effects on
striped bass and effects on photosynthesis
or growth in two species of marine algae.
Chronic effects on sheepshead minnow in
this range.
• 10.1-100.0 mg/1 Majority of acute toxicity values to marine
and freshwater fish and invertebrates occur
in this range. Concentrations on this
range affected growth, photosynthesis, and
respiration in two marine algae species.
• 100.1-1000.0 mg/1 Acutely toxic concentrations in this range
to two species each of marine and freshwater
algae, the adult sheepshead minnow and the
crab Cancer magister.
• >100.1 mg/1 Acutely toxic to the freshwater mosquito
fish (tested in turbid water).
6-10
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6.2 EXPOSURE OF AQUATIC BIOTA TO TOLUENE
6.2.1 Introduction
Toluene has been detected in wastewater effluents, in seawater
after controlled oil spills, in rainwater, and in sediment and fish
tissue from aquatic systems throughout the United States. In water,
its solubility is 534.8 mg/1 in freshwater and 379.3 mg/1 in seawater.
However, toluene volatilizes from surface water to the atmosphere
quite readily.
This analysis discusses probable levels of toluene to which aquatic
biota may be exposed and compares these levels with concentrations known
to have acute or chronic toxic effects.
6.2.2 Exposure Routes
The available data suggest that the primary mechanism of toluene
toxicity in fish is direct uptake from solution in water, which causes
damage to gill tissue and results in increasing all permeability and CCb
poisoning (Morrow e£ al_. 1975, Buikeraa and Hendricks 1980b) . No infor-~
nation was found regarding ingestion of toluene by aquatic biota, or
the bioavailability of toluene adsorbed to the sediments.
6.2.3 Monitoring Data
The monitoring data for toluene are not extensive; therefore, it
is difficult to present a comprehensive description of toluene exposure
levels in aquatic systems. Based on the available data, however, it
appears that where toluene has been detected it was almost always found
in low (ug/1) concentrations. The STORET system recorded approximately
450 observations of toluene in the ambient water of 17 states. Of these,
86 (19%) were unremarked values (above the detection limit) (U.S. EPA
1980b). The range of unremarked values was from 0.0 to 3900 ug/1, with
86% of these (74) ^100 ug/1. Effluent data from STORET indicated 205
(40%) unremarked observations, a total of 510 values reported in 24
states. The range of these values was from 0.0 to 4600 ug/1. Approx-
imately 19 effluent observations were > 100 yg/1.
Of the 100 reported observations of toluene levels in sediment,
only 7 were > 500 ug/kg. The higher concentrations were found in the
vicinity of an industrial area in San Francisco. The percentage dis-
tributions of ambient and effluent data, both remarked and unremarked,
are shown in Table 4-4. Unremarked data (U.S. EPA 1980b) are summarized
below:
6-11
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Unremarked Values of Toluene Concentrations from STOSET Data
Observations Concentrations Ranges
Sample Source (No.) (ag/1)
Ambient Water 86 0.0 - 3900 yg/1
(12 values > 100 ug/1)
Effluent Water 205 0.0 - 4600
6.2.4 Modeling Data
Data from EXAMS indicate that nearly all toluene at steady state
in each of the five aquatic systems remains in the water column rather
than partitioning into the sediments. In the rivers, volatilization
and biodegradation account for losses, although transport downstream
is the major loss mechanism for the short river segment examined. In
the lakes, > 90% of the chemical is lost to the atmosphere. Predictions
of water column concentrations for all other aquatic systems are in the
lov ug/1 range.
6.2.5 Conclusions
The monitoring data indicate that where toluene has been detected
in aquatic environments, the concentrations are generally low. This
holds true for discharge concentrations as well. EXAMS data predict
that, in general, toluene would not persist in the water column where
it would be available to biota. EXAMS does not predict substantial
deposition of toluene to the sediments, and the available monitoring
data do not indicate high sediment concentrations. There does not
appear to be an overlap between observed or predicted levels of toluene
in water or sediment (low ug/1 range) and concentrations that have been
found to be acutely or chronically toxic to aquatic organisms (1.0 to
10.0 mg/1, threshold of acute toxic effects). Therefore, neither eco-
system damage or toxic effects in individual aquatic species are
expected to take place in freshwater situations.
In seawater, especially in estuarine waters, combined, low-level
exposure of fishes to toluene from oil spills is a cause for concern.
The effects from this type exposure are not as immediately evident as
those from the catastrophic, short-lived events, e.g., tanker spills.
In the long run, however, they may place marine subpopulations at
greater risk.
6-12
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Although toluene is less soluble in seawater than benzene, it may
be more toxic and may show greater accumulation and longer persistance
(Korn e_t _al. 1977). Accumulated toluene will cause a greater demand of
energy for metabolization, detoxification, and depuration; thus, it may
cause long-term physiological damage (Anonymous 1977).
The long-term importance of fish survival throughout chronic exposure
cannot be underestimated. The ubiquitous nature of oil spills, small
and large, in estuarine waters and the rapid uptake and accumulation of
toluene following even brief exposures render this an area of potential
risk and one for further research.
6-13
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REFERENCES
Anonymous. An investigation of Che effects of discharged wastes on
kelp. Calif. State Water Control Bd., ?ubl. No. 26:58; 196*. (As
cited in U.S. EPA 1980a)
Anonymous. Fish accumulate benzene, toluene — Water-soluble components
of crude oil — after brief contact. Marine Fisheries Review; December
1977.
Benville, P.E.; Korn, S. The acute toxicity of six monocyclic crude
oil components to striped bass (Morone saxatilis) and bay shrimp
(Crago franciscorum). Calif. Fish Game 63(4):204-209; 1977.
Brerninan, G. et al. A continuous flow bioassay method to evaluate the
effects of outboard motor exhausts and selected aromatic toxicants on
fish. Water Res. 10:165; 1976. (As cited in Buikema and Hendricks
1980)
Buikema, A.L.; Hendricks, A.C. Benzene, xylene, and toluene in aquatic
systems: a review. Washington, DC: American Petroluem Institute;
1980.
Caldwell, R.S.; Caladrone, E.M.; Mallon, M.H. Effects of a seawater-
soluble fraction of cook inlet crude oil and its major aromatic
components on larval stages of one Dugeness carb, Cancer maeister
dana. In: Fate and effects of petroluem hydrocarbon in marine
organisms and ecosystems. New York, NY: Pergamon Press; 1976.
(As cited in Buikema and Hendricks 1980)
Dunstan, W.M.; Atkinson, L.P.; Navoli, J. Stimulation and inhibition
of phytoplankton growth by low molecular weight hydrocarbons. Mar.
Biol. 31:305-310; 1975. (As cited in Buikena and Hendricks 1980)
Kauss, P.B.; Hutchinson, T.C. The effects of water soluble petroleum
components on the growth of chlorella vulgaris. Beijernick. Environ.
Pollut. 9:157-174; 1975. (As cited in Buikema and Hendricks 1980)
Korn, S.; Hirsh, N.; Struhsaker, J.W. The uptake, distribution, and
l^C toluene in Pacific herring, Clupea harengus pallasi. Fish. Bull.
75(3):633-636; 1977. (As cited in Buikema and Hendricks 1980)
Morrow, J.E.; Gynitz, R.L.; Kirton, M.P. Effects of some components to
crude oil on young coho salmon. Copeia 1975(2):326-331; 1975. (As
cited in Buikema and Hendricks 1980)
National Research Council (NRC). The alkyl benzenes. Washington, DC:
National Research Council; 1980.
6-14
-------
Pickering, Q.H.; Henderson, C. Acute toxicity of some important petro-
chemical to fish. J. Water Pollut. Control Fed. 38(9):1419-1429; 1966.
(As cited in Buikena and Hendricks 1980)
Potera, G.T. The effects of benzene, toluene, and ethyl benzene on
several important members of the estuarine ecosystem. Diss. Abstr.
B. 36(5):2010; 1975. (As cited in Bulk etna and Hendricks 1980)
Price, K.S.; Waggy, G.T.; Conway, R.A. Brine shrimp bioassay and
seawater BOD of petrochemicals. J. Water Pollut. Control Fed. 46(1):
63-77; 1974. (As cited in Buikeoia and Hendricks 1980)
Tatem, H.E. Toxicity and physiological effects of oil and petroleum
hydrocarbons on estuarine grass shrimp Palaemonetes pugio. Ph.D.
dissertation. Texas A&M University; 1975. (As cited in U.S. EPA
1980a)
U.S. Environmental Protection Agency (U.S. EPA). In-depth studies on
health and environmental impacts of selected water pollutants. EPA
PB-01-4646. Washington, DC: U.S. Environmental Protection Agency;
1978. (As cited in U.S. EPA 1980a)
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria document for toluene. EPA 440/5-80-075. Washington, DC:
Office of Water Regulations and Standards, U.S. Environmental Protection
Agency; 1980a.
U.S. Environmental Protection Agency (U.S. EPA). STORE!. Washington,
DC: Monitoring and Data Support Division, U.S. Environmental Protection
Agency; 1980b.
Wallen, I.E.; McGreer, W.; Lasater, R. Toxicity to Cambusia affinis of
certain pure chemicals in turbid water. Sewage Ind. Wastes 26(6):
695-711; 1957. (As cited in Buikeaa and Hendricks 1980)
6-15
-------
7.0 RISK CONSIDERATIONS
7.1 HUMAN RISKS
Toluene is widely dispersed in the human environment, primarily as
a result of gasoline-based source emissions. However, the fate processes
affecting the toluene released to the environment favor atmospheric
destruction.
The data base on the potential carcinogenicity of toluene is
limited and inadequate for quantitative estimations of human risks.
Presently available data indicate no toluene-induced carcinogenic
or mutagenic effects in experimental animals. The U.S. EPA (1980a)
has also stated that available oncogenic data are insufficient to
evaluate the carcinogenic potential of toluene.
For comparative purposes, the relative margins of safety associated
with various human exposures to toluene were calculated by comparing no-
observed-effect levels in experimental animals (adjusted for a slower
rate of metabolism in humans) with typical nonoccupational exposure
levels. It was presumed that effect does not depend on route, but rather
on absorption rate (e.g., mg/day). The U.S. EPA (1980a) based the water
quality criteria on the study of Wolf e£ _aJL. (1956), which indicated a
maximum no-effect level of 590 mg/kg 5 days/wk for 193 days in a chronic
toxicity test in rats. Assuming that humans have a slower metabolism of
1/2 to 1/6 the rate in rats (see Section 5.1.5), a no-effect level for a
70-kilogram man is estimated as:
590 mg/kg/day x 5/7 x (1/2 or 1/6) x 70 kg = 5 - 15 gs/day
A somewhat lower range for a no-effect level was calculated in
Section 5.1.5, which indicated that 2.6-7.8 gm/day may be a no-effect
level for reproductive toxicity in pregnant women based on studies in
rats (Hudak and Ungvary 1978). Syrovadko (1977) and Matsushita (1975)
conducted studies on occupationally-exposed women (see Section 5.1.3.5).
These studies could imply that even lower levels of toluene exposure may
have toxic effects on the fetus or reproductive processes in women;
however, these investigators did not assess co-exposure to other solvents
and toxicants, which confounds the evaluation of their findings.
The NIOSK criteria document has listed 100 ppn (377 mg/in3) as the
threshold limit value (air) for toluene (RTECS 1980). This allows a
worker to absorb ^1.8 gm/8-hr work day, which is somewhat lower than the
no-effect dose range for human reproductive toxicity calculated above.
Exposure at greater than 100 ppn has been observed to cause acute CNS
symptoms — fatigue, weakness, confusion, and paresthesia.
7-1
-------
To compute margins of safety for typical exposure levels observed
for the general population, a no-effect level of 1.8 gin/day absorbed
dose has been assumed. Margins of safety are given in Table 7-1 and
range, for typical nonoccupational exposures, from 1200 for cigarette
smoking to greater than 1,000,000 for typical absorption of toluene
through drinking water. In conclusion, ingestion from all sources con-
stitutes a very small risk in comparison to inhalation absorption.
Percutaneous absorption through the use of paints and paint removers
could constitute a greater risk than ingestion exposure; however, in
terms of total population exposed and actual exposure conditions, the
percutaneous absorption estimated in Table 7-1 is regarded as approxi-
mate and probably higher than typically occurs.
The margin of safety for people living in urban areas (Scenario A,
approximately 74% of the U.S. population) is "oOOO vs ^40,000 for people
living in rural and remote areas (Scenario B, approximately 26% of the
U.S. population). The addition of cigarette smoking is calculated to
reduce the overall margin of safety for both urban and rural dwellers
to about 1000.
7.2 AQUATIC ORGANISM RISKS
Concentrations of toluene documented to have adverse effects on
aquatic species have been observed on rare occasions (less than ten
observations reported in STORE!) in ambient and effluent waters. Pre-
sumably, these concentrations result from localized discharges of toluene.
Because toluene is transported rapidly from water to air via volatiliza-
tion, however, these concentrations will be short-lived in the water
column. Thus, it is not expected that toluene poses a significant risk
to aquatic biota on a species or community level. An event, such as an
oil spill, may result in a localized, short-term high exposure to levels
of toluene. However, the risk associated with this exposure cannot be
quantified at this time.
7-2
-------
TABLE 7-1. ESTIMATED XARGIXS OF SAFETY FOR SXPOSraE TO TOLUENE
Exposure
Route/ Scer.aria
Ingestian
Water
- All surface supplies
- High end of distribution
of surface supplies
roses
- Fish tissues
-ghalatiaa
- Urban areas
- Sa-ote areas
- Use of gasoline scations
Exposure
Concentration
Tvoical Range
(ug/1)
Absorbed
Dose teg/dav)°
Tyaical Range
0.24 MD-19
1.3 0.1-19
fag/kg)
0.5
3.0
7-38
?-38
1.0 HD-35
(us/a3!
6.5
19
1
360
0.15-283
ND-3.3
100-5400
210
11
10
1.7-3170
?-43
1-65
- Ocsaostional: ac OSHA 754,000
standard
3,500.000
- Cigarette 100
Persutar.eous (mg/hr^
- Occupational--! hands 40
unprotected
- Consuser products 1
Trial Exposure Scenarios
- Scenario A — Urban environaent
(*74? of U.S. population)
- Scenario 3 — Rural environment
("'Z6" of U.S. population)
Margin of Safety"
Tvoical Range
ix!0°
6xl03
3xlC"
9000
5x10-:
flOOO-?
6000-10'
ixlO4-?
3xlOi-:xi06
1560
3200 3200-20,000 600
104-103
370(1900)d 5000(900)d
51(1600) 4X104(1COO)
90-600
aData iron Section 4.3, Monitoring Levels in the Environment.
bData fron Table 5-9.
cMargin of safety based on the absorbed dose at TL7 of 100 ppa (377 ag/a3)
for an 8-hour day divided by the absorbed dose fron typical source(s) of exposure.
Xusbers in parentheses include exposure fron cigarette sacking.
7-3
-------
REFERENCES
Hudak, A.; Ungvary, G. Eabryotoxic effects of benzene and its nethyl
derivatives: toluene and xylene. Toxicology 11:55-63; 1978.
Matsushita, I. e£ al. Hematological and neuro-muscular response of
workers exposed to low concentration of toluene vapor. Ind. Health
13:115; 1975. (As cited by U.S. EPA 1980b)
Registry of Toxic Effects of Chemical Substances (RTECS), 1979 edition.
Cincinnati, OH: U.S. Department of Health and Human Services, Public
Health Services Center for Disease Control, National Institute for
Occupational Safety and Health; 1980.
Syrovadko, O.N. Working conditions and health status of women handling
organosiliceous varnishes containing toluene. Gig. Tr. Prof. Zabol.
12:15; 1977. (As cited by U.S. EPA 1980b)
U.S. Environmental Protection Agency (U.S. EPA). Problem oriented report.
Carcinogen assessment of toluene. Carcinogen Assessment Group.
Washington, DC: Office of Health and Environmental Assessment, Office
of Research and Development, U.S. Environmental Protection Agency; 1980b.
U.S. Environmental Protection Agency (U.S. EPA). Ambient water quality
criteria for toluene. Report No. EPA 440/5-80-075. Washington, DC:
Office of Water Regulations and Standards, Criteria and Standards
Division, U.S. Environmental Protection Agency; 1980b.
Wolf, M.A. et al. Toxicological studies of certain alkylated benzenes
and benzene. Arch. Ind. Health 14:387; 1956. (As cited by U.S. EPA
1980a)
7-4
-------
Appendix A
Section 3.2.1 Calculation of Isolated Toluene Production and Capacity
1. Catalytic Refonaate and Pyrolysis Gasoline
Toluene production fron petroleum products was reporteo to be 4,010 x 103 kke by
a projection for 1978 (SR!, 1979). This was divided between catalytic refonr.ate
(3,632 x 103 kkg) and pyrolysis gasoline (378 x 103 kkc). However, 1978 toluene
production from petroleum sources was 3,433 x 10.3 kkg (USITC, 1979). Production
from petroleum sources was apportioned between catalytic refonr.ate and pyrclysis
gasoline, on the basis of the preliminary distributions, to be 3,109 x 10J kkg and
32« x 103 kkg, respectively.
2. Styrene Manufacture
Approximately 0.0551 (0.04 • 0.072 ) toluene are produced per kc of styrene
produced (SRI, 1979). 1978 styrene production was 3,260 x 1C- kkc froir. a capacity
of 3,830 x 103 kkg (USITC, 1979; SRI, 1979). However, this included production from
the Cxirane plant (450 x 103 kkg capacity) which does not produce styrene by dehy-
drogenation of ethylbenzene. Assuming that production from this plant was at the
same cacacity factor (85^) as the rest of the industry, ana that O.OS51 of toluene
are produced per kg of styrer.e, 1978 toluene production from styrene was 158 x 10£ 1
or 135 x 103 kkg, rounded to the nearest £,000 kkc.
Section 3.2.2 Non isolated Toluene
1. Catalytic R
The U.S. catalytic reforming capacity 1n 1979 was 6.03 x 108 liter of feed per
stream day (Oil & Gas Journal, 1979). Assuming 340 stream days/year, an average
yield of 85S of -charge capacity based en straight-run nashtha, and a toluene content
of 20S by volume In the re formate, 30.2 x 106 kkg were produced in 1975. (SSI, 1979).
Subtracting the 3.11 x 10° kkg recovered from catalytic refonnate from this yields
27.1 x 10^ kkg not isolated from the refonnate.
2. Coal Derived
Coke oven light oil from which products were not derived amounted to 374 x 106 liter
(DOE. 1979). Assuming a toluene content of 16S by volume (12%-202 range), 52 x 103
kkg were not Isolated from this source.
For those coke oven plants which don't recover light oil, toluene production is
estimated to be 22 x 1QJ kkg from the following:
- 64.7 x 10 kkg of coal consumed for coke production.
- 11.9 liters light oil/kkg coal carbonized (2.85 gal/ton).
• 165 toluene in light oil.
- 612 x 106l light oil recovered (DOE. 1979; EPA, 1979 SRI, 1579).
Nonrecovered toluene from coal tar is calculated to be 22 x 10 kkg based on
the following: 2. OS x 10s liters of coal tar produced, toluene content of 0.92
by weight, specific gravity of 1.2 for coal tar (USTIC. 1979; O'Brochta and
Woolbridge, 1945; Rhodes. 1954).
A-l
-------
Appendix A
Section 3.2.3 Environmental Releases form Toluene Production
Air emissions were calculated from the emissions factors in Table A-l
and total production from each source* assuming that the same emissions
factors may be applied to toluene produced as BTX or otherwise not isolated
(see Table A-2).
Releases from coking operations producing nonisolated toluene were
derived from the information presented in Table A-3, total coke production
of 44 x 10*> kkg and the following distribution of wastewater: direct dis-
charge 33", POTW - 25%, quenching - 40", deep well injection - 2% (DOE,
1979, EPA, 1979h). Toluene in wastewater sent to quenching operations is
sent to a sump and then recycled to quenching operations where one third
is evaporated during each pass. Toluene releases from quenching are ar-
bitrarily assumed to be evenly distributed between land and air.
Until more analysis is done, toluene from petroleum refinery waste-
water is assumed to be negligible for the reasons stated in text. Land
releases from refineries and toluene isolation from coke ovens were de-
rived by analogy to benzene, using (1) toluene production from each source,
(2) a solid waste generation factor of 0.003 and (3) an estimate of 1"
toluene in the solid waste (EPA, 1980f). Due to the nature of the data
(i.e., assumptions, engineering judgement, estimates), distribution on
a per plant basis is not realistic and therefore not presented.
A-2
-------
Appendix A
Section 3.2.4 (Table 3-2)
1. Transportation Spills
a. Oil:
Water figure based on 3.6 x 1071 of various oils - crude (263) t dlesel (18*0.
fuel (422), waste (22). lube (0.32), other (1.7%) spilled In navigable waters
1n 1978 (U.S. Coast Guard, 1980). Toluene Is estimated to have a 5-6 hr half-
life in oil spill solution (Kackay and Lelnonen. 1975).
Land figure based on 5.1 x 10 1 crude oil spilled In 1973 by common carrier
(23S), private carrier (225). ran (6S) and "other" (49S) (U.S. Ceot. of
Transoortation, 19SO). Average oil density » 0.85, toluene content: 1.3'-. (by
weight).
b. Gasoline:
Water - 1.1 x 1071 spilled: aviation/automobile gasoline (982) and Natural
(Casinghead) Gasoline (23) (U.S. Coast Guard, 198C).
Land - 3.7 x 1061 spilled: common carrier (53S), private carrier (4/f:), rail
(0.5%) "other" (eO.OlS) (U.S. Oept. of Transportation, 1980). Gasoline density:
0.73, toluene content: 8.5* (by weight).
c. Toluene:
Water - 2,500 1 spilled in navigable waters in 1978 (U.S. Coast Guard, 1980).
Land - 12,0001 spilled: common carrie* (94s.), private carrier (2"). ra<1
(4%) (U.S. Oept. of Transportation, 1980). Toluene density: 0.86E9.
2. Ethylene - Propylene Rubber Manufacture
Air emissions based on 1978 oroduction of ethylene-propylene rubber (inducing oil
content of oil-extended elastomers) of 1.3 x 105 kkg (USITC, 1979). Emission
factor: 0.5 kg tolaene/kkg product (EPA, 1977a). It is estimated that 1CS of the
total production is accounted for by the extension oils, which can contain toluene
(SRI, 1979). See Appendix 3 for a list of various extension oils.
3. Wood Preserving
Water discharge based on a flow weighted mean of 35 kg toluene released/year/
plant practicing steaming operations and 180 plants which have steaming operations
(EPA, 1979f). Raw wastewater figure.
4. Insulation Board Manufacture
Water discharge based on: 50ug/l toluene in raw wastewater; 16 plants, producing
a total of 3.3 x 108 m2 Insulation board 13 mm thick; board density • 0.33 kkg/nu;
and 9.2 x 103/1 kkg production average flow per plant (EPA, 1979f). Total dis-
charge: 650 kg toluene.
5. Hardboard Manufacture
Water discharae based on average raw wastewater concentration of 39<.g/l toluene;
average oer plant flow of 18 x 10? 1/kkg produced; 1.5 x 10° kkg/yr production
(EPA, 1979f). Total discharae: 1 kkg.
A-3
-------
Appendix A
Section 3.2.4 (Table 3-2 concluded)
6. AcrylonitrHe Manufacture
Air emission based on a t
emission factor of 0.074 kg toluene/kkg oroduct (EPA, 1977).
Air emission based on a total production of 7.9 x 1C5 kkg in 1973 (USITC, 1979) and
7. Combustion of Coal Refuse Piles
Air emissions derived from total hydrocarbon ercissions/yr from this source of
3.4 x 104 kkg, and an average of 13?» toluene In emissions (EPA, 1978a).
8. Stationary Fuel Corr-bustion, Forest Fires, Agricultural Burning, Structural Fires
Only total hydrocarbon emissions for each category *ere available (EP1, !S77b).
The precent which is toluene is estimated here to be an craer of magnitude less
than for coal refuse piles (132; EPA, 1978a) and an order of magnitude more tran for
landfills (0.13 ; SCAQMO, 1979). Therefore, these totals represent IS of the total
hydrocanon emissions from each category.
9 Cigarette Smoke
Based on an average of 33-.g toluene emitted/cigarette smoked (NAS, 1930), ana
6 x IQll cigarettes smoked/yr (Oept. of Agriculture, 1579).
Section 3 (Table 3-1)
1. Gasoline
Air emission figure Is a ccmolnatlcn of evaporative losses from use, evaporative
losses from marketing, and exnaust emissions.
Tne following factors are used:
- 7.4 x 10 bbl/day gasoline consumption (Oil and Gas Journal, 1979)
• 42 gal/bbl gasoline.
- 14.7 miles/gal average mileage (EPA. 1975a).
- 0.33 g/mile hydrocarbon evaporative loss during gasoline use in automobiles
(EPA. 1975b), toluene 1s 1.26% of total hydrocarbon emission (CARS, 1975).
- 3.2 g/mile hydrocarbons in exhaust (EPA, 1975b), 122 of which 1s toluene
(EPA, 1977b).
- 0.004735 kg hydrocarbon lost/kg gasoline during marketing (EPA, 1975a). 1.265
toluene (CARB. 1975).
- Density of gasoline: 0.73 kg/1
- 3.7851 • 1 gal.
A-4
-------
Appendix A
Section 3.2 Chemical Synthesis (Table 3-6)
1. Toluene Consumption Per Category Based On:
Benzyl Chloride
Benzoic Acid
Xylene Disproporticnation
p-Cresol
Benzaldehyde
Vinyl Toluene
0.8 unit toluene consumed/unit
product
plants operating at 553 capacity
0.84 toluene/product
62% of capacity
1.09 toluene/product (benzene
+ xylenes)
49.53 of caoacity
1.06-1.13 toluene/product
2.2 toluene/product
unknown :.' of capacity
1.1 toluene/product
832 of capacity
A-5
-------
Appendix A
Section 3.4 Environmental Releases (Table 3-7)
1. Gum and Wood Products
Wastewater flow based on 1) a total flow of 82,000 1/kkg product for all 6 subcate-
gories of the industry: Essential Oils; Rosin Derivatives; Sulfate Turpentine;
Gum Rosin and Turpentine; Wood Rosin, Turpentine and Pine Oil; and Tall Oil Rosin,
Pitch and Fatty Acids (EPA, 1979c) and 2) Production for 1978 of: Gum - 3 xlQ3
kkg, Turpentine - 82 x 1Q.3 kkg, Wood Rosin - 108 x 103 kkg, Tall Oil - 199 x 103
kkg (SRI, 1979), for a total of 397 x 103 kkg.
A-6
-------
Table A-l. [mission Factors
Source
Toluene Production - Catalytic Reformate
Toluene Production - Pyrolysis Gasoline
Toluene Production - Coal Derived
Toluene Production - Styrene By-product
Uenzoic Acid Production
Benzyl Chloride Production
Vinyl Toluene Production
Benzene Production
Xylenc Disproportionate
Toluene diisocyanate Production
p-Crcsol Production
Benzaldehyde Production
[mission
Process
0.00002
0.00015
0.00050
0.0000 I
0.00100
0.00055
0.00055
0.00005
0.00005
0.00077
0.00120
0.00090
Factor k
-------
Table A-2 Air Emissions, Calculations From Toluene Production
Source
Catalytic Reformate
Pyrolysis Gasoline
Styrene Manufacture
Coal Derived
Total Production
(kkg - 1979}
30,200,000
521,000
135,000
122,000
Emissions Factor
(kg lost/kg prcducaa)
0.00010
0.00090
0.00076
0.00125
Emissions (kkg
3,020
470
103
153
3,750
Source: EPA, 1980d, Appendix A, Notes from Section 3.2.2 and 3.2.3
Table A-3 Average Effluents from Coke Oven Operations
Stream
Waste Ammonia Liquor
Final Cooler Slow Down
Benzol Plant Wastes
liters produced/
kg coke
.16
.13
.20
toluene concentration (ir.g/1^
3.1
17
8.6
Source: EPA - 1979h.
A-8
-------
Table A-4. Toluere Materials Balance: Production Isolated from Petrsleum Refining, 1978 (kkg/yrj*
Ccnpany, Plant Location
Amerada Hess Carp.
St. Croix, Virgin Islands
American Petrofina, Inc.
Big Spring, TX
American Betrofina Co. of
Texas/Union 011 Cc. of
California (joint venture)
Beaunont TX
Ashland Oil, Inc.
Catlettsburg, KY
North Tonawanda, NY
Atlantic Rlcnfielo Co.
Channelvle*. TX
Houston, TX
Wilmington, CA
The Charte' Co.
Houston, TX
Coastal States Gai Corp.
Corpus Chnsti, TX
Cocnonwealth Oil Refining
Co.. Inc.
Penuelas, PR
Crown Central Petroleum
Corp.
Pasadena, TX
Tne Sow Chemical Co.
F-eeport, TX
Exxon Corp.
Bey town, TX
Getty Oil Co.
Delaware City. OS
El OoradO, KS
Gulf Oil Corp.
Alliance, LA
Philadelphia. PA
Port Arthur. TX
Kerr-McGee Corp.
Corpus Chnsti, TX
Marathon 011 CO.
Texas City. TX
Mobil Oil Coro.
Beaunont, TX
Honsanto Co.
Alvin (Chocolate
Bayon), TX
Pennzoil Co.
Shreveport, LA
Phillips Petroleum Cc.
Sweeney. TX
Guayama, PR
Quintar.a • Howell
Corpus Chrlstl . TX
Shell Chemical Co.
Deer Park. TX
Sun Company, Inc.
Corous Chrlstl. TX
Marcus Hook. PA
Toledo, OH
Tulsa, OK
Tenneco, Inc.
Chalmette, LA
Feeds toe K
CR
CR
CR
CR
CR
PS
CR
CR
CR
CR
CR
PS
CR
PG
CR
CR
CR
CR
CR
CR
PG
CR
CR
CR
PG
CR
PG
CR
CR
CR
CR
CR
CR
CR
CR
CR
CR
Deduction Capacity
460.000
164.000
125.000
99.000
39.000
105,000
125.000
49,000
39.000
56,000
395,000
49,000
46,000
13,000
411.000
QC
20.000
194.000
92,000
49.000
66.000
148,000
72.000
2BO.OOO
16.000
33.000
132.000
0'
33.000
335.000
56.000
197.000
138.000
151.000
247.000
66.000
115.000
Production
310.000
110,000
84.000
67.000
26.000
76,000
84,000
33.000
26.300
38.3CO
266.0CO
36.300
31.300
9 i^OC
277.330
0
13. SCO
130.330
62.000
33.000
43.303
100.000
49.000
189.000
15.000
22.300
96.000
22.000
226.000
38.000
133.000
93.000
1C2.000
166.000
44.000
78.300
Environmental Releases
A1re Wate-c Lar.s
31
11
8-4
6.7
2.6
68
S.4
3.3
2.5
3.8
27
32
3.1
3
28
0
1.3
13
6.2
3.3
43
10
4.9
19
2
2.2
3E
2.2
23
.3.8
13
9.3
10
16.6
4.4
7.8
A-9
-------
Table A-4. (Concluded)
C:m:any, Plant Location
Texaca, Inc.
Port Arthur, 7X
'•est.il'ie, NJ
Union Carcide Coro.
Taft. LA
Union Oil Company of
California
Leawit. IL
Union Pacific Coro.
Corous Chrlsti. TX
Total?
Fescstack6
CR
G»
PG
CR
CR
'rcduct'an Capacity
92,000
132,000
66,000
56.000
99.000
'rsduction
62 .000
39, COO
-------
I
»—•
I-*
Ethylene
Table A-5. Toluene Yields from Various Pyrolysls Kccdsa
Toluene, kg/kkg
Ethane
1-2
Propane
9-17
n-Dutane
21-22
Mid-crude
naphtha
99-140
C6-CR Gas oil. distilled
Raffinate
41.5
Atmospheric
112-138
Vacuum
142-14!
Source: SRI, 1979.
aCthylene plant of an annual production of 450,000 metric tons; ethane recycled to extinction.
-------
Table A-6. Tolusne Materials Balance: Production from Styrene Manufactjre, 137S (kkg)a
Company, Plant Location
American Hoechst Corp.
Baton Rouge, LA
Atlantic Richfield Co.
Beaver Valley, PA
Cos -i tar, Inc.
Carvi He, LA
DOM Chemical Co.
rreecort, TX
Mioland, MI
El Paso NatjraT Gas Cc.
Odessa, TX
Gulf 011 Corp.
Donaldsville, LA
Monsanto
Texas City, TX
Staneard Oil Co.
(Indiana)
Texas City, TX
Sun Company Inc.
Corpus Cnnsti, TX
United States Steel
Houston, TX
Totals
Styrene Capacity
400,000
100.000
590,000
660,000
UO.OOO
68,000
270,000
630,000
380,000
36,000
54,000
3 400,000
Toluene Produced
16,000
4,000
24,000
26,000
5,600
2,700
11,000
27,000
15,000
1,400
2.200
135,000
Environmental =.eless"
Air Water La
12
3
28
20
£
2
S
21
12
I
_2 _
100 a
See Appendix A Notes for calculations. Totals nay not add due to rounding; blanks Indicate data not available.
The data Is not substantiated to the point that per plant estimates can be made (see Appendix A Notes for
Section 3.2.3).
Source: SRI, 1979.
A-12
-------
Table A-7. Coke Oven Plants which Recover Crude Light Oils
Company
Alabama B.P. .
Keystone Coke
Allied Chem.
Anrco
Armco
Ashland 011
Ashland 011
Bethlehem Steel
Bethlehem Steel
Bethlehem Steel
Bethlehem Steelc
CF&I
Crucible
Cyclops
Donner Hanna
Erie C4C
Ford Motor
Inland*
Interlake
Interlace
Ironton Coke
J&L
JJL
JWR
.
-------
Table B-l. General Formulations Containing Toluene
Product
Toluene Content (%)
China Cement, Solvent Type
Contact Rubber Cement
Microfilm Cement, Cotton base
Model Cement
Plastic Cement, Polystyrene
Shoe Cements
Tire Repair, Tubeless Bonding Compounds
Paint Brush Cleaners
Stain, Spot, Lipstick, Rust Removers
Nail Polish
De-icers, Fuel System Antifreeze
Fabric Dyes
Indelible inks
Marking Inks
Stencil inks
Solvents and Thinners
20-30
solvents may contain toluene
27-30
(may contain) 20-25
24
"aromatic hydrocarbon solvents"
>80
benzene (+ toluene, xylene) 25-90
may contain toluene
35
30
solvents may contain toluene
80-SO
40-60
may contain toluene
Source: Gleason _et aj_., 1969
B-l
-------
Table B-2. Ethylene - Propylene Rubber Extender Oils which May Contain Toluene
Oi 1 Manufacturer
Sundex 53 Sun Oil Co.
Sundex 96 Sun Oil Co.
Dutrex 7 Shell Development
Circosol 2XA Sun Oil Co.
Call flux GP Golden Bear Oil Co.
Sovaloid N Socony Vacuum
Sovaloid 0 Socony Vacuum
Phillips 9002 Phillips Petroleum Co.
Nectcn 45 Penola, Inc.
Circle Light Oil Sun Oil Co.
Neville Heavy Oil Neville Co.
Bardol B Barrett
Source: General Tire and Rubber Co., 1955
B-2
-------
Table C-l. Frequency of Toluene Detection in Industrial Wastewaters
Industry
Frequency (// found/<' samples)
Soap and Detergents
Adhesives and Sealants
Leather Tanning
Textile Products
Gum and Wood Products
Pulp and Paper
Timber
Printing and Publishing
Paint and Ink
Pesticides
Pharmaceuticals
Organics and Plastic
Rubber
Coal Mining
Ore Mining
Steam Electric Power Plants
Petroleum Refining
Iron and Steel
Foundries
Electroplating
Nonferrous Metals
Coil Coating
1/20
2/11
19/81
56/121
14/18
4/98
53/285
50/109
48/94
23/147
38/95
306/723
15/67
53/249
6/72
32/84
18/76
43/431
2/54
5/18
21/173
2/12
C-i
-------
Table C-l. (Concluded)
Industry Frequency (;t found/ # samples)
Photographic 9/25
Inorganic Chemical 10/107
Electrical 1/35
Auto and Other Laundries 9/56
Phosphates 1/33
Plastics Processing 1/1
Porcelain/Enameling 2/19
Landfill 3/7
Mechanical Products 23/35
POPds 11/40
Source: EPA, 1980a.
C-2
-------
Table C-2. Industrial Liquid Streams In which Toluene has been Detected
Cured Leather Goods Finishing
Steel Pipe and Tube Manufacture
Iron Sintering
Open Hearth Furnaces
Steel Industry:
Vacuum Degassing
Hot Forming
Blast Furnace
Alkaline Coating
Hot Coating
Cold Rolling
Electric Furnace
Basic Oxygen Furnace
Coal:
Mining
Physical and Mechanical Cleaning
Industrial and Commercial Laundries
Foundry Casting:
Primary Ferrous Industry
Al uminum
Textiles:
Blended Fabric Finishing
Polyester Fabric Finishing
Rubber Manufacture:
Polymerization Processing for Other Synthetic Rubber
Ore Mining and Milling:
Titanium
Silver
Lead-Zinc
Ferro-Alloys
Source: EPA, 1980c.
C-3
-------
Appendix 0
I
Cooll
st<
M »it«r
Til
HjSO,.
Sutfonatlon
Cooling »••.»-
Sttsf ' 1
<2 *
^
Cooling wj*i>r
0,-^tlon
eis^
Condensation
Cool In]
Stesr
KCN
Cevirutlon
wate-
Tl
NHj
»,»«,.
' Be«itlie 1
Source: EPA, 1977a
0 = Air Emission
A - Water Discharge
CJ= Land Release
D-l
-------
Appendix 0
Cooling vater
Stean I!
Oilditlen
I
Cooll
Stc
no, water
•Fill
fuel Ceot.«g -
|Hi Steai
\ ~ 4
IT
7
TransaUylatlon HydrageMt'fl*
Stean
li-p
CMorlnation
1 Hydro! vs
-------
Appendix D
VIM, «<»""« "•«
1 T A "T 11
Myijrclylif
T-.
Amlnatlen
r~\
\y
!
Coon
H
no water
T II
7>
' A
Nitration
T
I A
Hydrat1on
•
Benic"e
1 .
Condensation
Stean
T
Amonolysts
Ing «atfr
T II
HNOj
' 'V
Dilution
CsoHnq *i'.er
1' . 1!
Siduetian
H:SC»
! H,SCi
lltrillen
HCi Coding hater
CuCI jl
J » /s II
Replacement
H.
( x^
°.eauc:ion
N3
frn- Chloro
Source: EPA, 1977a
0 = Air Emission
A = Water Discharge
= Land Release
D-3
-------
Aopendix 0
Cooling .«trr
T
(I
".' f "r
Oaimion
^q
Colon n
HiU
Caolir.j mtlef
T i . T 11
\^-X ^
Caollr.j .jur
"'fV- . T II
Arsroniil/ns .lur«t:gn
Caelln; .Her
Tr-. Til
Air
Mtf...H Q..M..
^
^_y
•UnCO,
1 A
I
.1«.Cril)2«tlc>n I
H«Jt
?'
I ^>
Reduction
^
Sli»
Beni/1 enle
t /\
ClttrlfiMtlon
Source: EPA, 1977a.
0 = Air Emissions
«* = Water Discharge
D = Land Release
D-4
-------
APPENDIX E
E.I ESTIMATION OF VOLATILIZAXIOM FROM VATER
Volatilization from water can be estimated using procedures des-
cribed in the literature. The mathematical modeling of volatilization
involves interphase exchange coefficients that depend on the chemical
and physical properties of the chemical in question, the presence of
other pollutants, and the physical properties of the water body and
atmosphere above it. Basic factors controlling volatilization are solu-
bility, molecular weight, and the vapor pressure of the chemical and
the nature of the air-water interface through which the chemical must
pass.
Volatilization estimates can be based on available laboratory and
environmental data. Because of the lack of data for most chemicals,
however, estimates of volatilization rates from surface waters on the
basis of mathematical data and laboratory measurements are necessarily
of unknown precision. Still, comparisons of experimental results with
theoretical predictions indicate that these predictive techniques
generally agree with actual processes within a factor of two or three
in most cases.
The methods described below have been used to estimate volatil-
ization from natural surface water. The EXAMS Model has been used
to investigate behavior in natural surface water bodies, however, this
method was not used as input to EXAMS. An inpuc parameter similar
to the reaeration coefficients described below is used in EXAMS to
estimate volatilization; this value was obtained elsewhere.
Minimum data required to estimate volatilization are:
• Chemical properties—vapor pressure, aqueous solubility,
molecular weight; and
• Environmental characteristics—wind speed, current speed,
depth of water body.
With these data, the volatilization rate of a chemical can be
estimated using the following procedure:
(1) Find or estimate the Henry's Law constant H from:
H - P/S atm-m3/mole
where P = vapor pressure, atm
S = aqueous solubility, mole/nr*.
When calculating H as a ratio of vapor pressure to solubility, it is
essential to have these data about the same temperature and applicable
E-l
-------
to the sane physical state of the compound. Data for pure compounds
should be used' because vapor pressure and solubilities of mixtures may
be suspect.
• ™ *\
(2) If H < 3 :< 10 ' atn-x /mole, volatilization can bs considere'-
un import ant as an intermedia transfer mechani.-.'n and no further cal-
culations are necessary.
(3) If H > 3 x 10 atra-m /mole, the chemical can be considered
volatile. The nondimensional Henry's law constnat K* should be
determined from:
H1 = H/RT (2)
where R = gas constant, 8.2 x 10 atm-m /mole K
7 = temperature, K.
At 20SC (293°K), RT is 2.4 x 10"2 atm-m3/raole.
(4) The liquid phase exchange coefficient k., must be estimated. This
coefficient results from a method that analyzes tiie volatilization
process on the basis of a two-lay«r film, one water and one air, which
separates the bulk or the water body from trie bulk of the air (LLss
snd Slater 1974) .
For a low molecular weight compound, l\ < 65,
k, = 20 V44/M cai/hr (3)
A*
where M = molecular weight of the chemical.
If M > 65, Southworth (1979) has developed equations to estimate
k . If the average wind speed is £ 1.9 m/sec,
0.969
. k .('curr ]TJT (4)
Kl \Z0.673 /T M
where V = water current velocitv, m/sec
curr
Z = depth of water body, m.
If wind speed is greater, than 1.9 m/sec and less than about 5 m/scc,
u.y&y ^^ 0>526 (v 1>9)
curr 1 /32 e wind .,
cn/lir
where- V . = wiiuls|>i:od, m/scc.
E-2
-------
Above 5 m/sec, liquid phase exchange coefficients are difficult to pre
dict and may range up to 70 cm/hr.
Values csL imnti'd by <>nii;it inn (4) rn.iv dlffi-r from Clui.so rstiin.il.i-d
by equation (3) du« to the different methods of analysis on wiiicn tilt-
equations are based.
(5) The gas phase exchange coefficient must be estimated. This too
is based on the two-film analysis. For a compound of M < 65 (I.iss
and Slater 1974),
k - 3000 vsM cm/hr (6)
g
If M > 65 (Southworth 1979),
k - 1137.5 (V . , •!• V ) V18/M cm/hr. (7)
g wind curr
(6) The Henry's law constant and gas and liquid phase exchange co-
efficients are used to compute the overall liquid phase mass transfer
coefficient, K^ (Liss and Slater 1974), which is an indicator of the
volatilization rate:
(H/RT)k kn 11 "K k,
C \
K =
L (H/RT)k +k, H'k
S - •
(7) The volatilization rate constant kr is
k = K, /Z- hr'1 .
v L
(8) Assuming a first order volatilization process, tiio concpntration
in the stream in the absence of continuing inputs at the location at
which volatilization occurs, is
c(t) = c e"kvC (10)
o
where c(t) = pollutant concentration in the water column at time C
c = initial pollutant concentration in the water column.
o
(9) The half-life in the water column for the pollutant volatilizing
at a first order rate is
c 0-69 Z
Tl/2
Another method is available for computing k for highly volatile
chemicals with H > 10 atm-nr /nole. This method is based on reaeration
rate coefficients (Smith and Bomberger 1979, Smith e_t al. 1979,
Tsivoglou 1967). The following data are required:
E-3
-------
• Ratio of federation rate of chemical to that of water; and
9 Raaeration rate of oxygen for water bodies in tiic environment
or streamflow parameters (velocity, scream bed slope, depth).
If the oxygen reaeration rate is known for a given wator body or type
of water body, the volatilization rate constant for the pollutant can
be estimated from (Smith and Bomberger 1979):
(k°) = (k'Vk0), . (k°) (12)
v' env v v lab v env v '
where k = first order volatilization rate constant for the
particular chtmical (hr'1)
k = reaeration rate constant for oxygen (lir~ )
env = designates values applicable to environmental
situations
lab = designates laboratory measured value?
This equation applies particularly to rivers. For lakes and ponds,
the following equation may be more accurate:
(kC) = (kC/k°) |'° (k°) (13)
v'env v v' lab v env. v '
Typical values of (k°) are given in the literature ard reported by
Smith st. al. (1979) :v env
Water 3odv (k°) hr'1
v -;nv.
Pond 0.0046-0.0096
River 0.008. 0.04-0.39
Lake 0.04-0.013
The values for ponds and lakes arc speculative and depend on depth.
MackayQand Yuen (1979) present the equations listed below, which
correlate k with river flow velocity, depth, and slope:
Tsivoglcu-Wallacs: k° - 638 V s hr'1 Mi)
v curr v '
Parkhursc-Poaieroy: k° = 1.08 (1 -«• 0.17 F2) (V ^s)°-0375 Hj.-l
Churchill .e al.: k° - O.OC102V2-593 z'3'085 s'0'323 hr"1 <«>
-- v curr
E-A
-------
If no slope daca ace available:
Isaacs-Gundy: *° = 0.223V z"1'3 hr"1 (17)
V C u j» *
.. » • 0 « 1 / » •• •» ~1 • 3w • —~— / 1 O \
Lansbein-Durun: KV = O.Z^j. vcu^- "r --3)
where V * river flow velocity (m/s)
curr
s = river bed slope = n drop/in run (nundimunsional)
Z = river depth (m)
F B Froude number = V /§Z, dimensionless
curr
g = acceleration of gravity - 9.8 ra/s .
Because none of the foregoing is clearly superior to the others,
the best approach is probably to use all equations that ara applicable
and then average the results. For a river 2 m deep flowing at 1 r./sec,
the reaeration rate is estimated as 0.042/hr. (kc/kc), , is known for
V V 13D
some chemicals (see Table E-l).
Ir a (kv/kv)]_a|, value is not knovn, one for a simU.irl-/ hinh v.)!-it: 1 ! ty
chemical should be a reasonable substitute.
In principle, k,, is the same as (KL/Z); however, because k*' has- the
depth and other water body characteristics embedded within it as a result
of using (ky)env, no adjustment is required for including it in t.'ie
first order volatilization eciuation.
E-J
-------
TABLE E-l. MEASURED REAESATION COEFFICIENT RATIOS FOR
HIGH-VOLATILITY COMPOUNDS
Compound
Chloroform
1,1-Dichloroethane
Oxygen
Benzo [b] thiophene
Dibsnzothiopnene
Benzene
Carbon dioxide
Carbon tetrachloride
Dicyciooentadiene
sthylene
Krypton
Prooane
Radon
Tetrachloroethylene
Trichloroethylene
H
/atnvm3\
\ mole J
3.8x1 O*3
S.SxlO'3
7.2x1 0'2
2.7x10'*
4.4x1 Q-4
5.5x10'5
2.3x1 0':
8.6
3.3x10-J
1x10':
Measured
n;/k;
(.57 = .02)
1.66 ±.n/
.71 ±.11
1.0
.38 = .08
.14
.57 = .02
.89 i .03
.S3 ± .07
.54 ± .02
.87 : .02
.82 : .08
.72 ±.01
.70 = .08
.52 ± .OS
.57 = . 15
Source: Snich i-C il. (1974)
S-6
-------
REFERENCES
Liss, P.S.; Slater, P.G. Flux of gases across Che air-sea interface.
Nature 247:181-184; 1974.
Mackay, D.; Yuen, T.K. Volatilization of organic contaminants froir.
rivers. Proc. 14th Canadian Synp; 1979. Water
Smith, J.H.; Bomberger, D.C. Prediction of volatilization rates of high
volatility chemicals from natural water bodies. Env. Sci. Technol.
14(11): 1332-1337; 1980.
Smith, J.H. Mabey, W.R.; Bohonos, N.; Holt, B.R.; Lee, S.S.; Chou, T.W.;
Bomberger, D.C.; Mill, T. Environmental pathways of selected chemicals
in freshwater systems. Part II. Laboratory studies. Athens, GA:
Office of Research and Development, U.S. Environmental Protection Agency;
1978.
Southworth, G.R. The role of volatilization in removing polycyclic
aromatic hydrocarbons from aquatic environments. Bull. Environ.
Ccntam. Toxicol. 21:507-514; "l979.
Tsivogilan, E.G. Tracer measurements of streets reaeration. Washington,
DC: Federal Water Pollution Control Administration; 1970.
c-/
-------
APPENDIX F
ESTIMATION OF AIR CONCENTRATIONS OF TOLUENE USING GAUSSIAN PLUME
DISPERSION
Turner (1969) provides a Gaussian plume dispersion modelling
technique, for the estimation of air concentrations downwind of an
emission source. Groundlevel concentration at the center of a plume
having the compound concentration distributed normally about the
center is given by:
C(x,o,o) - • exp
IT Oy QZ Uw
where c(x,o,o) = concentration of toluene at varying x coordinates and
at: zero y and z coordinates (mg/m^) t
Q • emission rate (ng/s),
CY = standard deviation in the crosswind direction of the
plume concentration distribution (see Figure F-l),
z = standard deviation in the vertical direction of the
plume concentration distribution (see Figure F-2),
u.rf - wind speed (m/s)
h » height of source (m)
In all cases, Uy. = 5 m/s, the atmospheric stability class is
neutral (D), and the heat of the source is negligible. (A source
wanner than the surrounding air would lead to plume rise as a result
of bouyancy.)
Toluene concentrations in air of various distances downwind were
estimated using this equation for two source heights (h) and two source
strengths (Q). The results are given in Section 4.4.3.1.
No chemical degradation processes were included in these estima-
tions.
F-l
-------
5000
1000
500
100
00
10
1.0
0.1
0.5
1 5
Distance Downwind (km)
100
FIGURE F-l. VERTICAL DISPERSION COEFFICEXT AS A FUNCTION
OF DOWNWIND DISTANCE FROM THE SOURCE
F-2
-------
10,000
5000
0.1
0.5 1 5
Distance Downwind (km)
10
50
100
FIGURE F-2. HORIZONTAL DISPERSION COEFFICIENT AS A RJNCTION OF
DOWNWIND DISTANCE FROM THE SOURCE
F-3
-------
REFERENCE
Turner, D.3. Workbook on atmospheric dispersion estimates. No. 99-AP-
26, Washington, DC: U.S. Public Health Service, 1969.
F-4
------- |