United States
Environmental Protection
Agency
Office of Health and
Environmental Assessment
Washington DC 20460
Research and Development
EPA-600/S8-82-008F Sept. 1983
Project Summary
Health Assessment Document
for Toluene
The Office of Health and Environ-
mental Assessment has prepared this
health assessment to serve as a source
document for EPA use. It is fully
expected that this document will also
serve the information needs of many
government agencies and private
groups that may be involved in
decision-making activities related to
toluene.
In the development of the
assessment document, the existing
scientific literature has been surveyed
in detail. Key studies have been
critically evaluated and conclusions
drawn such that the toxicological
consequences of exposure to toluene
have been qualitatively and
quantitatively identified. Observed
effect levels and other measures of
dose-response relationships are
discussed, where appropriate, in order
that the adverse health responses are
placed in perspective with observed
environmental levels.
This document evaluates health
effects associated with exposure to
toluene. Toluene is released into
environmental air as a result of
evaporative loss through automobile
use, industrial use as a solvent, from
coke oven production, and during
toluene production. The known health
effects primarily involve dysfunction of
the central nervous system (CNS). The
health information pertaining to
toluene is discussed in detail. This
document also discusses production,
sources, emissions, environmental
levels, and other information to place
toluene in a real-world perspective.
This Project Summary was developed
by EPA's Office of Health and Environ-
mental Assessment, Environmental
Criteria and Assessment Office, Re-
search Triangle Park, NC, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The principal intent of this document is
to evaluate health effects associated with
exposure to toluene. Toluene is released
into environmental air as a result of
evaporative loss during its production,
storage, consumer, and manufacturing
uses.
The known health effects primarily
involve dysfunction of the central
nervous system (CNS) following acute
experimental and occupational
exposures in the range of 200 to 1500
ppm (=750 to 5600 mg/m3). In addition to
evaluating the spectrum of health effects
associated with release of toluene to the
environment, this document also places
toluene in a real-world perspective by
discussing the following: (1) physical and
chemical properties, (2) production, use,
and release to the environment, (3) abate-
ment practices, (4) environmental fate,
transport, and persistence, (5) environ-
mental levels of exposure, (6) analytical
methodology, (7) exposed populations
and estimates of human exposure, (8)
pharmacokinetics, (9) ecosystem consid-
erations, (10) synergisms and autogonisms,
and (11) effects on aquatic species.
Chemical and Physical
Properties
Toluene, a homolog of benzene that
contains a single methyl group, is a clear,
colorless liquid at room temperature. It
has a boiling point of 110.6°C, a vapor
pressure of 28.7 toor at 25°C, and a
density of 0.8669 g/ml at 20°C. It is
slightly soluble in both fresh and salt
water (at 535 mg/l and 379 mg/l,
respectively) at a temperature of 25°C.
The physical properties of toluene indi-
cate that it is likely to be present in air,
and that toluene originally present in
water may be transferred to the atmos-
phere. Toluene can undergo photochemi-
cal reactions, particularly under atmos-
pheric smog conditions. In aqueous
media under conditions of water
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chlorination, toluene may be chlorinated
and subsequently hydrolyzed to benzal-
dehyde. This reaction may account for the
benzaldehyde detected in some finished
drinking waters.
Air Quality Considerations
Environmental Sources
Activities associated with automobiles
(marketing and evaporation of gasoline
and automobile exhaust) are the largest
single source of toluene release to the
atmosphere (677 million kg/year).
Industries using toluene as a solvent are
the second largest source (375 million
kg/year). These two sources account for
75% of the toluene emitted to the
atmosphere. The amount of toluene
released to other media in the
environment is small and is equal to
approximately 0.15% of the total amount
released to the atmosphere.
Levels
Toluene is the most prevalent aromatic
hydrocarbon in the atmosphere, with
average measured levels ranging from
0.14 to 59 ppb (S0.53 to 200 A
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toxic effects may occur in more sensitive
species at levels occasionally found in
surface waters (0.1 to 1.0 mg/l) and
sediments (0.1 to 1.0 mg/kg). These
concentrations are sufficiently close to
the toxic concentrations for sensitive
species to indicate that acute or chronic
toxic effects may occur in some polluted
habitats, especially after accidental spills
of toluene. Toluene has only a low
bioconcentration potential and is metab-
olized and rapidly depurated from fish,
indicating that toluene is unlikely to
biomagnify through aquatic food webs.
Health Effects Conclusions
Based on a few studies involving
controlled exposure of humans to toluene
vapors as well as some reports of
occupational incidents and voluntary
abuse, the dose-response relationships
for the acute effects in humans of single
short-term exposures to toluene can be
estimated as:
300 to 800 ppm
(1100 to 3000
mg/m3)
400 ppm
(1500 mg/m3)
Gross signs of inco-
ordination for exposure
periods up to 8 hours
Lacrimation and irri-
tation to the eyes and
throat
The Project Summary was prepared by staff of Syracuse Research Corporation,
Syracuse, NY 13210.
Mark M. Greenberg is the EPA Project Officer (see below).
The complete report, entitled "Health Assessment Document for Toluene," (Order
No. PB84-100056; Cost: $32.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Criteria and Assessment Office
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
«US GOVERNMENT PRINTING OFFICE 1983-659-017/7197
100 to 300 ppm Detectable signs of in-
(400 to 1100 mg/m3) coordination for expo-
sure periods up to 8 hrs
50 to 100 ppm
(200 to 400 mg/m3)
37 ppm
(150 mg/m3)
Subjective complaints
Perceptible to most
humans
In conclusion, exposure to ambient
levels of toluene is not likely to constitute
a significant hazard to the general
population.
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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