INVESTIGATION OF SELECTED
POTENTIAL
ENVIRONMENTAL CONTAMINANTS:
ASPHALT AND COAL TAR PITCH
FINAL REPORT
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF TOXIC SUBSTANCES
WASHINGTON, D.C. 20460
SEPTEMBER 1978
-------
EPA-560/2-77-005
INVESTIGATION OF SELECTED
POTENTIAL ENVIRONMENTAL CONTAMINANTS:
ASPHALT AND COAL TAR PITCH
Ruth P. Trosset, Ph.D
David Warshawsky, Ph.D.
Constance Lee Menefee, B.S.
Eula Binghara, Ph.D.
Department of Environmental Health
College of Medicine
University of Cincinnati
Cincinnati, Ohio 45267
Contract No.: 68-01-4188
Final Report
September, 1978
Project Officer: Elbert L. Dage
Prepared for
Office of Toxic Substances
U.S. Environmental Protection Agency
Washington, D. C. 20460
Document is available to the public through the National
Technical Information Service, Springfield, Virginia 22151
-------
NOTICE
This report has been reviewed by the Office of Toxic
Substances, Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents neces-
sarily reflect the views and policies of the Environmental Pro-
tection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
-------
- 1 -
TABLE OF CONTENTS
Executive Summary
Introduction
Glossary 6
I. PHYSICAL AND CHEMICAL PROPERTIES 8
A. Bituminous Materials 8
B. Asphaltic Materials 11
1. Petroleum Asphalt 11
a. Composition of Crude Oil 11
b. Types of Petroleum Asphalts 12
c. Fractionation of Asphalt 13
2. Native Bitumens 22
a. Native Asphalts 22
b. Asphaltites 23
C. Coal Tar Pitch 24
1. Source 24
2. Physical Properties 29
3. Chemical Properties 30
II. ENVIRONMENTAL EXPOSURE FACTORS: ASPHALT 40
A. Production and Consumption 40
1. Quantity Produced 40
2. Market Trends 40
3. Market Prices 43
4. Producers and Distributors 43
5. Production Methods 44
B. Uses 50
1. Major Uses 50
a. Paving 50
(1) Production and Consumption 50
(2) Materials 52
(3) Process Descriptions 53
b. Roofing 55
(1) Production and Consumption 55
(2) Products and Materials 58
(3) Process Descriptions 59
2. Minor Uses 61
3. Alternatives to the Use of Asphalt 62
-------
TABLE OF CONTENTS
(continued)
C. Environmental Contamination Potential 63
1. Controlled and Uncontrolled Emissions 63
a. Air Blowing 63
b. Roofing Mills 65
c. Hot Mix Plants 66
d. Paving 68
2. Contamination Potential of Asphalt
Transport and Storage 69
3. Contamination Potential from Disposal 69
4. Environmental Contamination Potential
from Use 70
5. Weathering and Microbial Degradation 71
III. ENVIRONMENTAL EXPOSURE FACTORS: COAL TAR PITCH 75
A. Production and Consumption 75
1. Quantity Produced 75
2. Market Trends 75
3. Market Prices 75
4. Producers and Distributors 81
5. Production Process 83
B. Uses 85
1. Major Uses 85
2. Minor Uses 87
C. Environmental Contamination Potential 88
1. Emissions from Production 88
a. Coke Ovens and Tar Distilleries 88
b. Graphite Manufacture 88
c. Other Production Processes 91
2. Contamination Potential from Storage,
Transport and Disposal 91
3. Contamination Potential from Use 93
4. Weathering 94
IV. ANALYTICAL METHODS 96
A. Sampling 96
-------
- Ill -
TABLE OF CONTENTS
(continued)
B. Methods of Sample Analysis 99
1. Separation Schemes 99
a. Solvent Extraction and/or
Precipitation 99
b. Solid-Liquid Extraction 100
c. Distillation 102
d. Chromatography 102
2. Identification iMethods 106
a. Infrared Spectroscopy (IR) 107
b. Fluorescence and Phosphorescence
Spectroscopy 107
c. Mass Spectrometry (MS) 109
d. Nuclear Magnetic Resonance
Spectrometry (NMR) 110
e. Ultraviolet Spectroscopy (UV) 110
f. Other Techniques 111
3. Discussion of Existing and Proposed
Analytical Methods 112
C. Monitoring 118
V. TOXICITY AND CLINICAL STUDIES IN MAN 120
A. Effects on Organ Systems 120
1. Effects of Asphalt 120
a. Effects on the Skin 120
b. Effects on the Respiratory System 120
2. Effects of Coal Tar Pitch 121
a. Effects on the Skin 121
b. Effects on the Eyes 123
c. Effects on the Respiratory System 124
d. Other Effects 124
B. Effects of Occupational Exposure 126
1. Exposure to Asphalt 126
a. Refineries 126
b. Other 127
2. Exposure to Coal Tar Pitch 128
a. Exposure during Production of Pitch 128
b. Exposure during Use 133
(1) Electrodes 133
(2) Patent Fuel (Briquettes) 136
(3) Other 137
-------
- iv -
TABLE OF CONTENTS
(continued)
3. Combined Exposure to Asphalt and Coal
Tar Pitch 140
a. Roofing 140
b. Paving 141
4. Prevention of Occupational Disease 143
C. Effects of Experimental Exposure
to Coal Tar Pitch 146
D. Effects of Experimental and Therapeutic
Exposure to Coal Tar Medications 147
VI. BIOLOGICAL EFFECTS ON ANIMALS AND PLANTS 151
A. Effects on Mammals and Birds 151
1. Poisonings 151
2. Toxicity 151
a. Coal Tar and Pitch 152
b. Coal Tar Medications 155
3. Carcinogenicity 156
a. Introduction 156
b. Asphalt 164
c. Tars and Pitches Derived from Coal 165
(I) Coal Tar 165
(2) Heavy Tars or Pitches 167
(3) Coal Tar Pitch 168
(4) Coal Tar Medications 169
(5) Other Coal-Derived Tars 170
B. Effects on Other Animals 171
1. Fish 171
2. Invertebrates 171
C. Effects on Vegetation 171
D. Effects on Microorganisms 172
E. In Vitro Studies 173
-------
- v -
TABLE OF CONTENTS
(continued)
Page
VII. REGULATIONS AND STANDARDS 174
A. Current Regulations 174
1. Environmental Protection Agency 174
2. Department of Transportation 174
3. Occupational Health Legislation in
Various Countries 175
4. Department of Labor, Occupational Safety
and Health Administration (OSHA) 175
a. Coal Tar Pitch Volatile Standard 175
b. Coal Tar Pitch Volatile Standard
Contested 177
5. Department of Health, Education, and
Welfare, National Institute for
Occupational Safety and Health (NIOSH) 178
a. Criteria Document: Asphalt 178
b. Criteria Document: Coal Tar Products 178
c. Registry of Toxic Effects of
Chemical Substances 179
B. Consensus and Similar Standards 179
1. National Safety Council (NSC) 179
2. American Conference of Governmental
Industrial Hygienists (ACGIH) 179
VIII. TECHNICAL SUMMARY 180
IX. RECOMMENDATIONS AND CONCLUSIONS 187
X. REFERENCES 194
List of Information Sources 228
-------
- vi -
LIST OF TABLES
Number Page
1-1 Elemental Analyses of Asphalt Fractions
and Natural Asphalts 14
1-2 Concentration Averages of Several
Parent PAH in Asphalt (ppm) 21
1-3 Typical Analyses (Percent by Weight)
of Tars 28
1-4 Terminology Applying to Analogous
Fractions as Determined by Four
Fractionation Procedures 32
1-5 Molecular Weight and Hydrogen to Carbon
Ratio of Medium-Soft Coke Oven Pitch 32
1-6 Compounds in Coal Tar Pitch or Refined Tar 34
1-7 PAH in Coal Tar 35
1-8 Major Components of German High-Temperature
Conversion Process Coal Tar 36
1-9 Predominant Structures in Coke Oven Tar 38
II-l United States Asphalt Production as Percent
of Petroleum Refinery Yield 41
II-2 Products Manufactured by U.S. Petroleum
Industry 45
II-3 Employment Size of Establishments (SIC 2951)
Paving Materials 51
II-4 The Top Ten Paving Mix Producers: 1974 51
II-5 Suggested Mixing and Application Temperatures
for Asphaltic Materials 56
II-6 Employment Size of Establishments (SIC 2952)
Roofing Materials 57
III-l Crude Tar Production and Processing: (Pitch
Production 1954-1975 76
-------
- vii -
LIST OF TABLES
(continued)
Number Page
III-2 Consumption of Coal Tar Pitch by Market
(Thousand Tons) 80
III-3 Pitch Sales and Value 82
III-4 Levels of Airborne PAH in Emissions Associated
with an Integrated Steel and Coke Operation 89
III-5 Composition of Fresh Fumes From Roofing Pitch 92
V-l Temperature of Carbonization and Reported
Excess of Lung Cancer 129
V-2 BaP Concentrations at a Czechoslovakian Pitch
Processing Coke Plant 131
V-3 Incidence of Cancer in Aluminum Workers Exposed
to Soderberg or Prebaked Anodes 135
V-4 Mortality Ratios for Several Causes of Death
in Roofers 142
VI-1 Carcinogenicity of Asphalts, Tars, and Pitches
Applied to the Skin 157
VI-2 Carcinogenicity of Injected Asphalt and Coal
Tar Samples 160
VI-3 Carcinogenicity of Inhaled Asphalt and Coal
Tar Samples 161
VII-1 Some Recognized Occupational Cancers for which
Compensation is Given in Various Countries 176
-------
- viii -
LIST OF FIGURES
Number Page
1-1 Partial Classification of Bituminous Materials 9
1-2 Fractionation of Asphalt 16
1-3 Stepwise Fractionation of Various Components
of Asphalt 20
1-4 Origin of Coal Tar Pitch 27
II-l Annual Domestic Sales of Asphalt by Major
Markets 42
II-2 Refinery Steps in the Production of Asphalt 47
III-l Crude Coal Tar Produced and Processed in
By-Product Coke Ovens 77
III-2- Annual Pitch Production and Sales 1954-1975 78
-------
- 1 -
EXECUTIVE SUMMARY
Asphalt and coal tar pitch are bituminous materials used as binders,
saturants and weatherproof coatings. Although they are similar in certain
physical properties, they differ markedly in origin, composition, major
uses, and severity of biological effects.
Asphalt
Petroleum asphalt is the residue, essentially uncracked, from the
fractional distillation of crude oil. Small amounts of naturally occurring
asphaltic materials are also used.
Commercial grades of asphalt are prepared to meet standard specifications
based on physical properties. Base stocks of asphalt can be formulated
from residues of distillation, solvent deasphalting, or air blowing processes.
Liquid (cutback) asphalts are prepared by diluting base stocks with organic
solvents. Emulsions of asphalt and water are also used.
Since 1970 annual asphalt sales in the United States have averaged
31 million tons. Seventy-eight percent of the asphalt is used in paving,
17% in roofing, and 5% in miscellaneous applications, including dam linings,
soil stabilizers and electrical insulation.
Emissions from airblowing and from manufacture of paving and roofing
materials have not been well characterized, but may contain entrained as-
phalt droplets, gases, trace metals, hydrocarbons, and large quantities of
particulates which may contain polynuclear aromatic hydrocarbons (PAH),
several of which are carcinogens.
A ninety-nine percent control level of the emissions from asphalt
production and processing is possible using currently available thermal
-------
- 2 -
afterburners (fume incinerators) in conjunction with wet scrubbing units.
Installation of paving and roofing materials may be a localized source of
air pollution. Emissions can be greatly reduced by maintaining the asphalt
heating kettle temperature below 216°C during roofing operations, and by
using emulsions to replace cutback asphalts for paving.
Vast surfaces of asphalt covered roads, parking lots, runways and play-
grounds are subject to microbial, chemical and physical degradation, which
may produce some polycyclic aromatic, heterocyclic, and metallic substances,
possibly toxic or carcinogenic, in air, waterways and sediments.
Limited animal skin painting and inhalation studies suggest that as-
phalt may be, at most, weakly carcinogenic. Other health hazards have not
been demonstrated.
Few human exposure studies are available. Harmful effects from asphalt
cannot be identified in exposures to mixtures of asphalt and the more bio-
logically potent coal tar pitch, which have been common in paving, roofing,
and weatherproofing operations. It is generally agreed that asphalt is a
relatively harmless material to workers under proper working conditions (U.S.
National Institute for Occupational Safety and Health, 1977a).
Present regulations limit particulate emissions from new asphalt hot
mix plants and regulate effluent levels for new and existing paving and
roofing point sources using tars and asphalts. The NIOSH recommended standard
for occupational exposure to asphalt fumes is 5 mg airborne particulates per
cubic meter of air (U.S. National Institute for Occupational Safety and Health,
1977a). Although the OSHA standard on "coal tar pitch volatiles" has been
interpreted to include asphalt, the standard has not been successfully enforced.
-------
- 3 -
Coal Tar Pitch
Crude coal tar is a highly cracked product evolved during carbonization
of coal. All coal tar pitch commercially available in the U.S. is the distil- -
lation residue of by-product coke oven tar. The amount of pitch produced
has declined from 2,004,000 tons in 1965 to 1,227,000 tons in 1976. About
62% of this pitch is used as a binder or impregnant in carbon and graphite
products. The largest single carbon product market is for carbon anodes
used in primary aluminum manufacture. About 17% of the pitch produced is
burned as an open-hearth furnace fuel, and 7% is used for the manufacture
of "tar" saturated roofing felt and for certain commercial roofs. A stable
market for pitch (10,000 tons annually) has been its use as a binder in
"clay pigeons" for skeet shooting. Pitch bonded and pitch impregnated re-
fractory bricks used to line basic oxygen furnaces, blast furnaces and foundry
cupolas represent a steadily growing market.
Pitch can undergo the same basic processing as does asphalt, namely
air blowing, dilution with coal tar solvents, or emulsification with water.
Emissions from manufacturing processes using pitch may include large amounts
of pitch dust as well as pitch volatiles. Air pollution control measures used
for asphalt fumes can also be used to contain emmissions from pitch. Large
amounts of volatiles are emitted during the production of prebaked and graphi-
tized pitch-containing carbon products, a major use of pitch. During use of
such materials, higher levels of emissions are generated by self-burning elec-
trodes than by those that have been prebaked or graphitized before use.
A large proportion of workers exposed to pitch and sunlight develop
moderate to severe acute phototoxic reactions of the skin and eyes. Exposure to
pitch and coal tar can cause skin cancer (U.S. National Institute for Occupa-
tional Safety and Health, 1977b). Inhalation of fumes and particulates may be
-------
- 4 -
related to increased incidence of lung cancer. Some cases of cancer of the
bladder and certain other organs may be related to exposure to coal tar pitch.
Although they do contain carcinogenic PAH, topical medications based on crude
coal tar, which have been widely used for the prolonged treatment of chronic
skin diseases, do not appear to have caused cancer in humans when properly
used.
Some attempt has been made to control worker exposure to emissions from
coal tar pitch. The present standard for "coal tar pitch volatiles" (other
than coke oven emissions) specifies that worker exposure to airborne con-
centrations of pitch volatiles (benzene soluble fraction) shall not exceed
0.2 mg per cubic meter of air (U.S. Department of Labor, 1977) . The cur-
rent interpretation of the coal tar pitch volatile standard covers volatiles
from distillation residues not only of coal, but also of other organic ma-
terials including petroleum (i.e., asphalt). Because coal tar pitch vola-
tiles are considered carcinogenic, the National Institute for Occupational
Safety and Health (1977b) has recommended a standard for occupational ex-
posure to coal tar products, including coal tar pitch, of 0.1 mg cyclohexane
solubles per cubic meter of air (the lowest detectable limit).
Examination of the literature indicates that the biological effects of
asphalt are probably limited. Large quantities, however, are processed and
the major uses are in roofing and paving products that are permanently ex-
posed to slow degradation in the environment. Coal tar pitch, on the other
hand, produces acute effects in a large proportion of exposed workers as well
as possible increased risk of cancer of several sites after prolonged ex-
posure. The major uses of pitch involve occupational rather than environmental
exposure.
-------
- 5 -
INTRODUCTION
Asphalt and coal tar pitch are used in a variety of industrial pro-
cesses and manufactured products that utilize their properties as thermoplastic,
durable, cementitious, water-resistant materials. The Environmental Pro-
tection Agency, Office of Toxic Substances, has requested a preliminary
literature investigation of the environmental contamination potential
of these two bituminous materials. This noncritical review is intended to
serve as a source of information to be used in evaluation of the severity of
the environmental hazard and the need for further action concerning these
two materials.
In this report, "asphalt" is considered to be the residue, essentially
uncracked, from the fractional distillation of crude petroleum. Coal tar
pitch is defined as the residual product from the distillation of crude coal
tar, a cracked material, which is formed during the coking of coal.
A survey of the literature since 1954 was conducted, referring to
older literature when recent information was unavailable. The literature
review includes composition and properties; production figures and process
descriptions; contamination potential from manufacture and use,' analysis,'
toxicity and carcinogenicity to humans, animals, and plants; recommended
handling practices; legislation; and standards. Conclusions and recommendations
based on the literature are also presented.
-------
- 6 -
GLOSSARY
ASPHALT - A black to dark-brown solid or semisolid cementitious material
in which the major constituents are bitumens. Asphalt occurs naturally
(asphaltites and native asphalts) or is obtained as the residue, essentially
uncracked, from the straight distillation of petroleum.
BITUMEN - A mixture, completely soluble in carbon disulfide, of hydro-
carbons of natural and/or pyrogenous origin and their nonmetallic deriva-
tives .
BITUMINOUS MATERIAL - A mixture, containing bitumen or constituting the
source of bitumen, occurring as natural (asphaltite, tar sand, oil shale,
petroleum) or manufactured (coal tar pitch, petroleum asphalt, wax)
material.
COAL TAR - A brown or black bituminous material, liquid or semisolid in
consistency, obtained as the condensate in the destructive distillation
(coking) of coal, and yielding substantial quantities of coal tar pitch
as a residue when distilled.
COAL TAR PITCH - A black or dark-brown material obtained as the residue
in the partial or fractional distillation of crude coal tar. As con-
trasted to petroleum asphalt, which is essentially uncracked, coal tar
pitch is a highly cracked material.
-------
- 7 -
COAL TAR PITCH VOLATILES - The fumes from the distillation residue of coal
tar. In legal use, this term refers to the volatiles from the distillation
residues of coal, petroleum or other organic matter. In this report, use
of this term in connection with asphalt fumes has been avoided except in
discussion of the legal definitions.
CRACKING - A process (e.g., pyrolysis, thermal treating, coking) whereby
large molecules (as in oil or coal) are decomposed into smaller, lower
boiling molecules, while reactive molecules thus formed are recombined
to create large molecules (including PAH) different from those in the
original stock.
PETROLEUM PITCH - A cracked product resulting from pyrolysis of gas oil
or fuel oil tars. Because it shares certain properties with coal tar
pitch, it has been suggested as a replacement for it in some applications.
This term should never be used to refer to an asphalt product. Petroleum
pitch is not included within the scope of this report.
Abbreviations:
BaP Benzo(a)pyrene
BeP Benzo(e)pyrene
CTPV "Coal tar pitch volatiles" (see Glossary)
PAH Polynuclear aromatic hydrocarbons
PNA Polynuclear aromatic compounds, including both hydrocarbons
and heterocyclics (use in this report has been avoided)
PPOM Particulate polycyclic organic matter
-------
- 8 -
I. PHYSICAL AND CHEMICAL PROPERTIES
A. Bituminous Materials
Asphalt and coal tar pitch belong to a group known as bituminous materials.
Bitumens are defined as mixtures of hydrocarbons and their norunetallic deri-
vatives of natural or manufactured origin, which are completely soluble in
carbon disulfide (Hoiberg, 1965a,b).
In British and European usage, however, the term "bitumen" is used to refer
to the material known in the United States as "asphalt," Among the many ma-
terials which may be considered as bituminous, only native and manufactured
asphalts and manufactured coal tar pitch, as shown in Figure 1-1, will be dis-
cussed in this review.
Asphalt is a dark brown to black cementitious solid or semisolid material,
composed predominantly of high molecular weight hydrocarbons, occurring either
as a native deposit or as a component of crude petroleum, from which it is
separated as a distillation residue without pyrolysis. The asphalt content
of crude oils varies from 9 to 75% (Ball, 1965), and the nature of the asphalt
varies with its parent crude. About 98% of the asphalt used in the United States
is derived from crude petroleum (Miles, 1977).
Coal tar pitch is the distillation residue of crude coal tar, which is a
pyrolysis product from the high temperature carbonization (coking) of coal.
Coal tar pitches, brownish black to black in color and containing at least 5000
compounds, range from viscous liquids at ordinary temperature to materials
which behave as brittle solids exhibiting a characteristic conchoidal fracture
(McNeil, 1969).
-------
msliUation
Gas Oil,
'icatinq OiU,ekc.
cok«
«n
o
V
RESIDUE
JNlWE
Native A
Gmharnite,
Manjak
Native/ Asphalts
Truiidadl fLake
SancU
Bermurlez Cnke Asphalt
..
Oil
X
Oil
Cteosobe.
^{JkrtUjerve, OIL, ebc.
FIGURE 1-1. PARTIAL CLASSIFICATION OF BITUMINOUS MATERIALS
-------
- 10 -
Because the uses of asphalt and pitch depend largely on physical prop-
erties, specifications are based on empirical tests using strictly defined
procedures. Most of these tests are covered by standards of the American
Society for Testing and Materials (ASTM) (1973) and the American Associa-
tion of State Highway Officials (AASHO). The Asphalt Institute (1974a)
presents brief descriptions of tests and methods for asphalt. A few of these
tests are as follows:
Penetration - a measure of consistency expressed as the distance,
in tenths of a millimeter, that a standard needle penetrates under
known conditions of loading, time and temperature.
Softening point (ring and ball,, R & B) - the temperature at which a
standard weight ball sinks below the bottom of a standard ring
containing asphalt.
Viscosity - a measure of the consistency of asphalt at two set
temperatures. Normally, the viscosity-graded asphalt cements are
identified by viscosity ranges at 60 and 135°C.. Sixty
degrees is the approximate maximum temperature used in pouring
asphalt, and 135°C is the approximate mixing and laydown temperature
for hot asphalt pavements.
Flash point - the temperature to which asphalt may be safely heated
without an instantaneous flash in the presence of an open flame.
Ductility - the distance in air which a standard briquet at 25°C can be
elongated before breaking.
Solubility - a measure of purity of the asphalt, determined by dissolving
the asphalt in trichloroethylene and separating the soluble and insoluble
portions by filtration.
Water content - generally measured by refluxing asphalt product with
-------
- 11 -
xylol or high-boiling-range petroleum naphtha and collecting and
measuring the water condensate in a trap.
Specific gravity - the ratio of the weight of a given volume of
bituminous material to that of an equal volume of water at the
same temperature, usually reported as 77/77°F.
B. Asphaltic Materials
1. Petroleum Asphalt
a. Composition of crude oil
As indicated in the beginning of this chapter, the asphalt content of
crude oil varies (9-75%) and the nature of asphalt varies with its parent
crude. Crude oil is a very complex mixture and no single crude oil has
ever been completely defined (Rossini and Mair, 1951, 1959; Rossini et al.,
1953; Altgelt and Gouw, 1975). The enormous diversity of different crude
oils extends from light oils to heavy types found in asphalt lakes. These
variations are found not only in the viscosity, but also in the content and
length of paraffinic chains, number of aromatic carbon atoms, degree of
ring fusion and type and amount of hetero atoms.
More than several hundred compounds have been identified in Ponca City
(Oklahoma) crude oil. They have been classified into nonpolar and polar
materials. The nonpolar group includes straight chain alkanes, (hexane,
pentane), branched alkanes .(isooctane), cycloalkanes (butylcyclohexane),
and aromatics (propylbenzene and propyltettralin). The polar group in-
cludes acids such as naphthenic acids, phenols, alkylthiols, cycloalkylthiols,
alkylthiophenes, pyridines, quinolines, indoles, pyrroles and porphyrins.
Nickel (49-345 ppm, Berry and Wallace, 1974) and vanadium (0.3 to 0.6 weight
percent) are the most prominent trace metals that occur in petroleum (Atlas
and Bartha, 1973; Yen, 1972). Calcium, magnesium, titanium, cobalt, tin,
-------
- 12 -
zinc, and iron are also metals commonly found in crude petroleum. These metals
tend to accumulate in the residue.
b. Types of petroleum asphalts
Distillation is the primary means for separating crude petroleum fractions.
Asphalt is the high-boiling residual fraction. Crude oil may be distilled first
at atmospheric pressure to remove the lower boiling fractions such as gasoline
or kerosine and then can be further processed by vacuum distillation, leaving
a straight-run asphalt. The asphaltic residue may also be processed with
liquid propane or butane. Vacuum distillation and propane deasphalting both
affect the hardness of the residue. When processed from the same stock,
propane deasphalted residue differs little from straight-run residue (Corbett,
1966; Hoiberg e_t al., 1963; Hoiberg, 1965a). Straight-run asphalt accounts
for 70 to 75% of all the asphalt produced.
Airblown asphalts with modified properties as compared to straight run
asphalt are produced from the asphalt stock by treatment with air at tempera-
tures of 200 to 280°C. Catalysts such as phosphorus pentoxide, ferric oxide
or zinc chloride/used in concentrations from 0.1 to 3%xreduce the air blowing
time. The asphalt undergoes dehydrogenation and polymerization by ester
formation and carbon linkage (Smith and Schweyer, 1967; Haley, 1975; Corbett,
1975) during these processes. The presence of dicarboxylic anhydrides in
oxidized asphalts has been confirmed by infrared spectroscopy (Petersen et al.,
1975). There is a decrease in the aromatic resin content and an increase
in the asphaltene content and hydrogen bonding basicity of airblown asphalt
(Harbour and Petersen, 1974). Air blowing results in a product with a
higher softening point for given penetration than straight reduced asphalt,
while catalytic air blowing produces a still higher softening point. Air
blown asphalt, which accounts for 25 to 30% of asphalts used, is a
-------
- 13 -
viscous .material that is less susceptible to temperature change than straight
run asphalt.
Treatment of asphalt at high temperature (480-590°C) and pressure (200 psig)
produces thermal asphalts, less than 5% of total production of asphalt, which
are not commonly available because catalytic cracking for the production of
gasoline has largely replaced thermal cracking. Such asphalts are characterized
by a relatively high specific gravity, low viscosity and poor temperature
susceptibility (little change in consistency with increased temperature).
They have a lower hydrocarbon to carbon ratio than, straight run asphalts.
Highly cracked residues have infrared spectra similar to those of coal tar
pitches CCorbett, 1965; Hoiberg £t a^., 1963; Hoiberg, 1965a). The vis-
cosity is more susceptible to temperature change in thermal asphalts than
in straight run asphalt.
An elemental analysis of asphaltic residues (% by weight) shows carbon
ranging from 80 to 89%, hydrogen from 7 to 12%, oxygen from 0 to 3%, sulfur
from trace to 8% and nitrogen from trace to 1% (Table 1-1).
c. Fractionatipn of asphalt
The high molecular weight (M.W. 100-2500) asphaltene fraction is precipi-
table by n-pentane, hexane or naphtha and, despite source, appears constant in
composition as determined by carbon-hydrogen analysis. Asphaltenes are solid
at room temperature and show some degree of crystallinity by X-ray diffraction.
The concentration of asphaltenes to a large extent determines the viscosity
of asphalt (Altgelt and Harle, 1975; Reerink, 1973; Reerink and Lijzenga, 1973) .
Maltenes, the nonprecipitated fraction, are generally considered to
contain resins CM.W. 500-1000) characterized by high temperature susceptibility
that are either adsorbed on activated clays or precipitated by sulfuric acid
-------
TABLE I-l. ELEMENTAL ANALYSES OF ASPHALT FRACTIONS AND NATURAL ASPHALTS
Softening Penet
point (ring 20.
and ball)
°C
.ration, Elemental analyses, % by wt
c,°r ratio,
C H S N Oa C/H
Petroleum
Straight run
asphaltenes
petrolenes
Air-blown
asphaltenes
petrolenes
Highly cracked
50-70
80-90
50
12-46
21-38
80.5-83.5 7.3-8.0 4.6-8.3 0.4-0.9 0-1.8 0.85-0.97
82.0-84.8 10.0-10.6 0.4-5.5 0.5-0.5 0.7-1.4 0.65-0.70
80.7-84.8 7.8-8.2 3.7-7.3 0.5-0.8 2.0-2.8 0.82-0.88
82.5-84.3 10.9-11.5 2.3-5.4 0.4 0.8-1.3 0.62-0.64
36
asphaltenes
petrolenes
Native
Trinidad 90-91
Bermudez 60-70
88
87
1.5-4 80
20-30 82
.9
.9
.82
.9
5
7
10
10
.9
.9
.7
.8
3
3
6
5
.0
.7
.8
.9
0
0
0
0
.4
.5
.8
.8
1
0
0
0
.25
.93
.64
.64
a Oxygen determined by difference
Sources: Hoiberg e_t al^. , 1963
-------
- 15 -
or a solvent (acetone, isobutyl alcohol, propane). The nonprecipitable maltene
fraction consists of oils (M.W. 250-600) which may contain appreciable quantities
of wax and are characterized by low temperature susceptibility.
The petrolene fraction (M.W. 500-1000) boils below 300°C and is soluble in
low-boiling saturated hydrocarbons such as n-pentane.
In addition, asphalts may contain saponifiable material and acids,
the content of which is determined as percent naphthenic acids in the original
crude (Corbett, 1966; Hoiberg, 1965a; Hoiberg ejt al_., 1963).
Most separations of asphalt into its constitutional components rely on some
type of preliminary fractionation (Figure 1-2) prior to the use of gel permea-
tion, gas-liquid, paper, gravity fed column or high performance chromatography
(Couper, 1977; Schweyer, 1975). The fractions obtained are then further analyzed
by use of ultraviolet spectrometry, nuclear magnetic resonance, infrared spectros-
copy, electron spin resonance, atomic absorption or X-ray diffraction, as de-
scribed in Chapter IV.
Five principal operations (distillation, extraction, adsorption, precipi-
tation and chromatography) are used in various combinations for the fractionation
of asphaltic bitumens (Rostler, 1965; Hoiberg, 1965a; Hoiberg £t al_., 1963)
to produce a variety of fractions that can be classified into a few general
groupings (Figure 1-2). However, none of these fractionation methods have
provided satisfactory results when used separately.
Distillation
Distillation is used to concentrate the asphaltenes and maltenes and
to separate out the petrolenes. However, this method by itself is not useful
as an analytical separation procedure for complex mixtures (Hoiberg,1965).
-------
ASPHALT
n-pentane
4- 4
Insoluble So
ASPHALTENES MAL
luble
TENES
extraction, precipitation
or column chromatography
4, -J'
OILS RESINS
FIGURE 1-2. FRACTIONATION OF ASPHALT
-------
- 17 -
Extraction
Carbon disulfide has been used in the separation of asphalt into low
boiling petrolenes and a residual fraction, while n-pentane has been used as
a means of fractionating asphalt into asphaltenes and raaltenes. However,
these types of extractions give only a partial separation of asphalts (Rostler,
1965).
A more complex separation involves the Hoiberg method (Hoiberg and Garris,
1944) which separates the asphalt stepwise into five fractions: (1) asphaltenes
(2) hard resins, (3) waxes, (4) soft resins, and (5) oils. The Traxler-Schweyer
method (1953), a simplified Hoiberg method, consists of stepwise separation into
(1) asphaltenes precipitated by n-butanol and (2) a n-butanol-soluble fraction
consisting of paraffins and naphthenes. Lastly, the method of Knowles et al.
(1958) involves stepwise fractionation into-(l) asphaltenes, (2) soft and hard
resins, (3) waxes and (4) paraffinic and naphthenic oils. This last method
is valuable because it separates asphalts into waxes, two types of resins and
two kinds of oils.
Adsorption
Fractionation by adsorption has involved charcoal, charcoal and sand,
and various kinds of molecular sieves. Early methods consisted of heating
mixtures of liquid bitumens with adsorbents such as charcoal and fuller's earth,
followed by filtration. They are considered the predecessors of modern
chromatographic methods, which use the principles of both solvent extraction
and adsorption. Molecular sieves can still be considered to be a relatively
new tool which is being incorporated into separation procedures for asphaltic
bitumens (Rostler, 1965; Couper, 1977).
-------
- 18 -
Chroma tography
A number of fractionation methods have used chromatography, either by
itself or in combination with extraction and adsorption methods. Silica gel
is used to separate maltenes into resins and oils and maltenes or asphal--
tenes into non-aromatics, aromatics and polar compounds. The Glasgow-Ter-
mine method, which also uses silica gel, elutes two pentane fractions and one
fraction each of benzene, carbon tetrachloride and ethanol, while the
Hubbard-Stanfield method involves (1) precipitation of asphaltenes with
n-pentane, (2) elution of oils from alumina with n-pentane and (3) elution
of resins from alumina with methanol-benzene mixture. In each of these
methods, however, the overlapping of components from each fraction is typi-
cal for these chromatographic techniques (Rostler, 1965).
Two elaborate methods have been attempted by Kleinschmidt (1955) and
O'Donnell (1951). The Kleinschmidt method involves (1) precipitation of
asphaltenes with n-pentane, (2) elution of the n-pentane soluble fraction from
fullers earth to obtain (a) white oils with n-pentane, (b) dark oils with methy-
lene chloride/ (c) asphaltic resins with methyl ethyl ketone, ar.d (d) a black
residue desorbed with a mixture of acetone and chloroform. The O'Donnell method
involves molecular distillation on the basis of molecular size followed by silica
gel chromatography to separate saturates, aromatics, and resins. The saturates
are dewaxed followed by urea-complex formation to separate long chain paraffins,
and the aromatics are separated by alumina chromatography into mono- and di-cyclic
aromatics, followed by peroxide oxidation and another chromatography to separate
the benzothiophene analogs.
-------
- 19 -
Precipitation
The chemical precipitation methods, use excess amounts of reagents to remove
one component or fraction from the complex mixture. One method (Rostler, 1965)
involves the precipitation of asphaltenes by low boiling hydrocarbons, followed
by precipitation with sulfuric acid. The Rostler-Sternberg method (1949) in-
volves precipitation of asphaltenes with n-pentane and selective precipitation
of the nitrogen bases and acidaffins 1 and 2 by use of successive concentrations
of H2SC>4 (85%, 98%, fuming (S03)). The applicability of these methods to complex
mixtures is still under investigation. A more recent method by Corbett (1969)
uses n-heptane, benzene, and methanol-benzene-trichloroethylene as solvents
to obtain petrolenes, asphaltenes, saturates, aromatics and polar fractions.
All of the methods and combinations described above, as well as others
described in reviews (Couper, 1977; Schweyer, 1975; Altgelt and Harle, 1975),
have been used in analysis of the complex mixtures of various types of asphalts.
Figure 1-3 shows a composite stepwise fractionation of the various components
of asphalt.
Techniques such as solvent fractionation, thermal diffusion and sulfuric
acid precipitation and chromatography have yielded asphaltic fractions that have
been examined using infrared (Petersen et al., 1971) and ultraviolet specr
troinetryr X-ray diffraction, nuclear magnetic resonance, electron spin reson-r
ance and:atomic absorption (Couper, 1977).
Little is known at present about polynuclear aromatic hydrocarbons (PAH)
in asphalt. Wallcave et al. (1971) have presented average concentrations of
PAH in asphalt obtained from various sources (Table 1-2). More work needs to
be done in the area of PAH determinations in asphalt.
-------
ASPHALT
J_
ASPHALTENES
MALTENES
"1
REACTIVE
ASPHALTENES
NONREACTIVE
ASPHALTENES
RESINS
OILS
I
1st ACIDAFFINS
NITROGEN
BASES
2nd ACIDAFFINS
M
o
NAPHTHENES
ALIPHATICS
WAX
LIQUID
FIGURE 1-3. STEPWISE FRACTIONATION OF VARIOUS COMPONENTS OF ASPHALT
-------
TABLE 1-2* CONCENTRATION AVERAGES OF SEVERAL PARENT PAH IN ASPHALT (ppm)
Asphalt Phenanthrene Pyrene Benz[a]-
anthracene
1
2
3
4
5
6
7
8
2.3
0.4
3.5
1.3
0.6
^35
' 1.1
^2.3
0.6 0.15
1.8 2.1
4.0 1.1
8.3 0.7
0.9 0.9
38 35
0.3 0.2
0.08
Tri-
phenylene
0.25
6.1
3.1
3.4
3.8
7.6
1.0
0.3
Chrysene Benzo[a]-
pyrene
0.2 0.5
8.9 1.7
2.3 1.3
3.9 2.5
3.2 1.6
34 27
0.7 0.1
0.04
Benzofe]- Perylene Benzofghi]- Coronene
pyrene perylene
3.8 - 2.1 1.9
13 39 4.6 0.8
2.9 2.2 1.0 0.5
3.2 6.1 1.7 0.2 w
6.5 2.9 2.7 0.9 '
52 3.0 15 2.8
1.6 0.1 0.6 0.9
0.03 - Trace
Benzofluorenes, fluoranthene, benzo[k]fluoranthene, anthracene, picene and indeno[l,2,3-cd]pyrene
are present in trace amounts.
Source: Wallcave et al^v 1971
-------
- 22 -
As indicated previously, some of the metals present in crude oil tend to
accumulate in the asphalt. Vanadium, nickel, and iron tend to be concentrated
in the asphaltene fraction (Corbett, 1967), Vanadium chelates have been
studied in petroleum asphaltenes (Tynan and Yen, 1969; Wolsky and Chapman,
(1960).
Other metals are bound to polynuclear aromatic compounds containing
sulfur, nitrogen and oxygen polar groups as well as naphthenic and paraffinic
side chains. During air blowing, these polynuclear aromatics are converted
to asphaltenes. Removing the asphaltene fraction from blown asphalt can re-
move up to 97% of the organometallics.
2. Native Bitumens
Native bitumens include a wide variety of natural deposits ranging in
character from crude oil to sand and limestone strata impregnated with bi-
tuminous material. Only a few of these materials are classified as asphalts.
a. Native asphalts
The native asphalts include a variety of reddish brown to black materials
of semisolid, viscous-to-brittle character. They can occur in relatively pure
form, with 92 to 97% soluble in carbon disulfide and only 3 to 8% mineral con-
tent, as is the case for Bermudez (Venezuela) lake asphalt, or in less pure form,
wi-ch a carbon disulfide-soluble fraction of 39% and a mineral content of
27%, as is the case for Trinidad lake asphalt (Table 1-1). Trinidad lake as-
phalt is dull black and semiconchoidal in fracture, with a penetration of 10
at 30°C and a softening point (R & B) of 85° c. When gas and water are driven
off at 100°c, Trinidad asphalt loses 29% of its weight and the carbon disulfide-
soluble fraction increases to 56% while the mineral content increases to 38%.
-------
- 23 -
Frequently, the bitumen is found in pores and crevices of sandstones,
limestones or argillaceous sediments and is known as rock asphalt. The term
"tar sands" has been used by geologists to designate sands impregnated with
dense, viscous asphalt found in certain sedimentary structures, such as the
Athabasca tar sands now being mined in Alberta, Canada (Hanson, 1964; Broome,
1965; Camp, 1969; Breger, 1977).
b. Asphaltites
Asphaltites are naturally occurring, dark brown to black, solid, and
relatively nonvolatile bituminous substances differentiated from native as-
phalts primarily by their high content of n-pentane insoluble material
(asphaltene) and their high temperature of fusion, 115 to 330°C (R & B). Among
these are gilsonite, grahamite and manjak, all of which are in the pure state,
with close to 100% carbon disulfide solubility and less than 5% jnineral
content. Gilsonite, the native asphaltite most commonly used, is found
in western Colorado and eastern Utah. It is black in color with a bright
luster, a conchoidal fracture, and a penetration at 41°C of 3 to 8 with a
softening point (R & B) of 230 to 350°F (110 to 177°C). Gilsonite has a car-
bon content of 85 to 86%, is soluble in carbon disulfide to 98%, and has
a specific gravity of 1.03 to 1.10 at 25°C (77°F).
Grahamite is found in a single vertical fissure in a sandstone in
West Virginia. It has a specific gravity of 1.15 to 1.20 at 77°F and a
softening point (R & B) of 350 to 600°F (177 to 315°C), and a high tem-
perature of fusion which distinguishes it from gilsonite. Other deposits
in the United States, as well as in Mexico, Cuba and certain areas of
South America, have yielded bitumens corresponding in general to the graha-
mite in West Virginia, and are therefore referred to under this name.
-------
- 24 -
A third broad category is known as glance pitch or manjak, originally
mined in Barbados, West Indies. The specific gravity at 77°F (25°C) is
1.10 to 1.15, with a carbon content of 80 to 85%, a softening point (R s B)
of 230 to 350°F (110.to 177°C), a carbon disulfide soluble fraction of 95%,
a black color and a bright to fairly bright luster with a conchoidal to
hackly fracture. This asphaltite is considered an intermediate between graha-
mite and gilsonite because of its specific gravity and fixed carbon (Broome,
1965; Hanson, 1964; Hoiberg ejt a^., 1963; Breger, 1977).
C. Coal Tar Pitch
1. Source
Coal can be described as a compact stratified mass of vegetation^ inter-
spersed with smaller amounts of inorganic matter, which has been modified chemi-
ically and physically by agents over time. These agents include the action of
bacteria and fungi, oxidation, reduction, hydrolysis and condensation, and the
effects of heat and pressure in the presence of water. The chemical properties
of coal depend upon the amounts and ratios of different constituents present in
the vegetation, as well as the nature and quantity of inorganic material and the
changes which these constituents have undergone (Francis, 1961).
Coal, therefore, has a rather complicated chemical structure based on
carbon and hydrogen with varying amounts of oxygen, nitrogen and sulfur. Bi-
tuminous coal, from which coal tar pitch is derived, contains a number of PAH,
including carcinogenic benzo(a)pyrene (BaP) and benz(a)anthracene (Tye et al.,
1966), and a variety of toxic trace elements such as antimony, arsenic, beryllium,
cadmium, lead, nickel, chromium, cobalt, titanium, and vanadium (Zubovic, 1975).
When coal is pyrolyzed, a variety of changes occur: above 100°C free
water evaporates; above 200°C combined water and carbon dioxide are evolved;
above 350°C bituminous coals soften and melt, decomposition begins, and tar
-------
- 25 -
and gas are evolved; at 400 to 500°C most of the tar is evolved; at 450 to
550°C decomposition continues and the residue turns solid; above 550°C the
solid becomes coke and only gas is evolved; around 900°C no more gas is
evolved and only coke remains; above 900°C small physical changes occur
When coal undergoes carbonization, it passes through two steps of de-
composition: onset of plasticity at 350 to 500°C and advanced decomposition at
650 to 750°C. Volatile products released at each stage undergo a series of
secondary reactions as they pass through the coke before emerging from the
retort. The volatiles are separated by fractional condensation or absorption
into tar, ammoniacal liquor, benzole, and illuminating or heating gas (McNeil,
1966a).
The major reactions in the conversion of primary carbonization products
into tars (McNeil, 1966a) areJ
1) cracking of higher molecular weight paraffins to gaseous
paraffins and olefins;
2) dehydrogenation of alkylcyclic derivatives to aromatic
hydrocarbons and phenols;
3) dealkylation of aromatic, pyridine and phenol derivatives;
4) dehydroxylation of phenols;
5) synthesis of PAH by condensation of simpler structures;
6) disproportionation of PAH to both simpler and more complex
structures.
The temperature of carbonization and contact time with the hot coke
bed and heated walls of the retort will determine the composition of tars,
as well as the extent of the reactions. Tars from the different types of
carbonization processes vary widely as to their composition and characteristics.
-------
- 26 -
The term low temperature carbonization refers to pyrolysis of coal to a
final temperature of 700°C. The final solid product is a weak coke with
high yields of tar and oil and low yield of gas. High temperature carboni-
zation is pyrolysis of coal between 900°C and 1200°C, with town gas as the
product and coke as the by-product at the lower temperature and metallurgical
coke as the product and gas as the by-product at the higher temperature
CEncyclopaedia Britannica, 1974) .
Coal tar pitch is the residue from the processing of coal tar (Figure 1-4),
Pitches or "refined tars" are obtained from the distillation of tars and rep-
resent from 30 to 60% of the tar components (McNeil, 1966a) (Table 1-3).
Distillate oils (described later) obtained by steam or vacuum distillation of
pitch or pitch crystalloids or from coking of pitch are the only fractions
from which pure chemical compounds are isolated.
McNeil (1966a) has described the change in composition of tars found as
the temperature increases from vacuum distillation or low temperature carboni-
zation to high temperature carbonization:
(a) The amounts of paraffins and naphthenes decrease and
disappear, the naphthenes fading out before the paraffins.
(b) The amount of phenolic material falls from about 30% to a
small value.
(c) The proportion of aromatic hydrocarbons increases from a low
figure to over 90%.
(d) The proportions of aromatic, phenolic and heterocyclic
compounds containing alkyl side chains decrease markedly.
(e) The proportion of condensed ring compounds containing more
than three fused rings increases.
(f) The yield of coal carbonized decreases from 10% to less than 5%.
-------
CCM
V
'Upper boiliiur point U3O"c I
Includes benxe.ru., toluene, xulcnt.na^lilna, a
liv&tflts «hHirfrcenc. and creosote, Auctions.
TfiflEDTIK
ana toumattmc..
5.
IHC14
FIGURE 1-4. ORIGIN OF COAL TAR PITCH
i
N)
-------
- 28 -
TABLE 1-3
TYPICAL ANALYSES (PERCENT BY WEIGHT) OF TARS
Coke Oven Tar Gas Works Tar Low Temperature
Tar (200°C)
Pitch
Creosote
Light Oils
Heavy Oils
59.0
31.0
2.5
5.4
44.0
42.0
5.4
6.5
26.0
55.0
6.7
9.4
£
Source: Encyclopaedia Britannica, 1974
-------
- 29 -
2. Physical Properties
Coal tar pitch is a black or brownish black shiny material ranging from
a viscous liquid at ordinary temperatures (30 to 80°C) to a material which be-
haves as a brittle solid exhibiting a characteristic conchoidal fracture
(McNeil, 1966a; Lauer, 1974). At higher temperatures the brittle solid
pitch can become a viscous liquid. It has a characteristic "tarry" odor
described as a combination of smells of naphthalene and phenol modified by
small amounts of pyridine and thiophenol.
The residue from the primary distillation can have different viscosity
grades depending on how extensively the coal tar is distilled. If the dis-
tillation is continued to the desired softening point, the residue is called
"straight run" pitch to distinguish it from "cut-back" or "flux-back" pitch,
which is a straight run pitch of harder consistency cut back to the desired
softening point with tar-distillate oil (McNeil, 1969).
Since pitch is composed of a great number of different compounds, it
does not show a distinct melting or crystallizing point. Therefore, pitch is
usually characterized by the softening point, which can be determined by one
of several standard methods: ring and ball, cube in air, cube in water and
Kramer-Sarnow (McNeil, 1966b). Each of these methods represents the tempera-
ture at which a given viscosity or softness is attained under specific con-
ditions .
The softer grades of pitch having softening points (R &. B) below 50°C are
usually referred to as base tars or refined tars; other grades are soft pitch
(50 to 75°C), medium-hard pitch (85 to 95°C), and hard pitch (above 95°C)
(McNeil, 196S). - _
-------
- 30 -
In general, all pitches behave essentially as Newtonian liquids over
the range of viscosities which can be measured reliably. The only departure
from Newtonian flow in pitches is a slight reduction in viscosity with in-
creasing shearing stress found in samples with a high content of toluene in-
soluble materials.
3. Chemical Properties
It has been difficult to isolate and characterize compounds from this
complex bituminous material. It has been estimated that pitch contains five
to ten thousand compounds, of which 100 to 150 have been isolated and identi-
fied (McNeil, 1966b). Among those identified have been a large number of
PAH. Varying amounts of PAH are formed by secondary reactions occurring during
carbonization of coal.
Coal tar pitch is composed predominantly of carbon (86 to 93%) and hy-
drogen (5 to 7%), with small amounts of nitrogen (0.5 to 1.5%), oxygen, and
sulfur. Nitrogen is usually present in either five- or six - membered rings
or as nitrile substituent. Oxygen is present as phenolic and quinone sub-
stituents, as well as in four-, five-, or six- membered rings. Sulfur is
usually found in five-membered rings (McNeil, 1969). Analysis for certain
metals in coal tar has revealed high concentrations of zinc (over 200 yg/g)
and lead (70 to 75 yg/g); concentrations of between 1 and 10 yg/g of iron,
cadmium, nickel, chromium, and copper have been found (White, 1975). Mag-
nesium, boron and vanadium have also been identified in coal tar pitch
(Liggett, 1964).
Because of the importance of pitch in various industries, a number of
studies have been carried out to elucidate its structure. Most specifications
for coal tar pitches include limitations of solubility in certain solvents.
Different solvents are required for various specifications and the methods used
vary among investigators. These differences have made it difficult to compare
-------
- 31 -
results (McNeil, 1966b). Table 1-4 indicates several methods which may be
roughly equated.
The Demann (1933) and Broche and Nedelmann (1934) methods divide the
pitch into material insoluble in benzene (a-component), material soluble
in benzene but insoluble in petroleum ether (0-component) and material soluble
in petroleum ether (5-component). Adam et_ a!U (1937) extend the above methods
by separating the benzene extract into soluble and insoluble portions, by add-
ing the concentrated benzene extract to 10 times its volume of petroleum ether,
and by separating the a-component into pyridine soluble (€2) and pyridine in-
soluble (C^) fractions. The petroleum ether soluble portion is referred to
as "crystalloids" and the petroleum ether insoluble but benzene soluble por-
tion is called "resinoids." Crystalloids are also defined as being soluble in
hexane or similar aliphatic solvents.
Dickinson (1945) modifies the Adam, method by performing a vacuum dis-
tillation on the pitch to obtain distillate oils, extracting the residue with
benzene and pyridine, precipitating the benzene extract with petroleum ether
and extracting the precipitate with n-hexane. Resin A is that part of the
pitch soluble in n-hexane or petroleum ether; Resin B is that part of the
pitch insoluble in hexane but soluble in benzene and in fractions C^ and C2-
A solvent analysis method (Mallison, 1950) which has been widely used
in Europe divides the pitch into five fractions: H-resins, M-resins, N-resins,
m-oil^ and n-oils. The method is not a solvent fractionation and the fractions
are not further analyzed (McNeil, 1966b). A number of other solvent analysis
or fractionation methods that have been used are toluene and tetralin solvents;
carbon disulfide, pyridine, benzene, petroleum ether and diethyl ether;
pyridine, xylene and decalin; and nitrobenzene and acetone.
-------
- 32 -
TABLE 1-4. TERMINOLOGY APPLYING TO ANALOGOUS FRACTIONS AS DETERMINED
BY FOUR FRACTIONATION PROCEDURES
Adam et al .
(1937) ~
Cl
C2
Resinoids
Crystalloids
Dickinson
(1945)
Cl
C2
Resin B +
some Resin A
Distillate oils
+ some Resin A
Demann
(1933)
a-Fraction
B-Fraction
6 -Fraction
Mallison
(1950)
H-Resins
M-Resins
N-Resins
m-Oils and
n-oils
Source: McNeil, 19GGL
TABLE 1-5. MOLECULAR WEIGHT AND HYDROGEN TO CARBON
RATIO OF MEDIUM-SOFT COKE OVEN PITCH
Fraction
Wt. range %
Reported Av. atomic Solubility
mol. wt. H/C ratio
Crystalloid 45-60
Resinoid 16-24
C2 5-15
G! 3-28
258 0.67 Sol. petroleum
ether
559 0.62 insol. petroleum
ether, soluble
benzene
1476 0.70 insol. benzene
0.33 to 0.46 insol. pyridine,
quinoline
Source: McNeil, 1966b
-------
- 33 -
To indicate the variability in these separations, the H-resin content
is between 0.2 and 7.5% while M-resin content is 5.2 to 11.2% in vertical
retort tars. The variations in pitches from coke ovens are H-resins 2.8 to
14.4% and M-resin 3.8 to 28.2%. The same kind of variability holds true for
crystalloids (45 to 60%), resinoids (16 to 24%), C2 (5 to 15%) and C^ (3 to 28%)
in coke oven pitch. Tars from vertical retorts contain 55 to 70% in crystalloids
and less C± and resinoids while low temperature pitch contains less than 1% C±
and 7u to 80% crystalloids (McNeil, 1966b).
The molecular weight and hydrogen to carbon ratio of crystalloids, re-
sinoids, GI and C2 are represented in Table 1-5. The overall range in mole-
cular weight for coal tar is between 200 and 2000. The C^ fraction has a much
lower H/C ratio. Low temperature processes are found to have higher H/C ratios.
A value of 1.07 has been reported for the crystalloid fraction from continuous
vertical retort pitch (Greenhow and Smith, 1960).
The distillate oil fraction has been subjected to many analyses and is the
only fraction of pitch from which pure chemical compounds can be isolated by
techniques normally used, such as fractionation and chromatographic separation
methods. McNeil (1966b) has listed 126 compounds all boiling above 300°C (an
arbitrary cut off value), most of which are condensed PAH and their hetero-
cyclic analogs, from pitch or refined tar which is sufficiently volatile to
distill without decomposition. A partial list is shown in Table 1-6. PAH
found in refined coal tar and in high temperature conversion process coal
tar are listed in Tables 1-7 and 1-8, respectively.
The pitch crystalloids contain the same major components as the dis-
tillate oils. They are composed of polynuclear aromatics with an average
of 3 to 6 rings and with a molecular weight in the range of 200 to 250. Com-
pounds similar to those indicated in Table 1-6 are: acenaphthene, fluorene,
-------
- 34 -
TABLE 1-6. COMPOUNDS IN COAL TAR PITCH OR REFINED TAR
1-Naphthylamine
2-Naphthonitrile
3-Hydroxydiphenyleneoxide
Diphenylsulfide
Carbazole
4-Hydroxybipheny1
Phenanthridine
Acridine
Xanthene
2-Methylcarbazole
Anthracene
Phenanthrene
1-Methylfluorene
2-Azafluoranthene
13-Azafluoranthene
9-Methylphenanthrene
3-Methylphenanthrene
Pyrene
7H-Benzo(c)carbazole
7H-Benzo (a) carbazole
2-Phenylnaphthalene
Benzanthrone
Benz(a)acridine
Benz(c)acridine
Benzo(a)fluorene
Benzo(b)fluorene
Benzo(c)fluorene
3-Methylpyrene
Chrysene
Benz(a)anthracene
Tetracene
Triphenylene
Benzo(b)fluoranthene
Benzo(j)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Benzo(e)pyrene
Benzo(ghi)perylene
Picene
Benzo(b)triphenylene
DJLbenz (a/h) anthracene
Dibenz(a,j)anthracene
DibenzCa,h)pyrene
DibenzCa,i)pyrene
Source: McNeil/ 1966b
-------
- 35 -
TABLE 1-7. PAH IN COAL TAR
PNA
Anthracene
Benz [a] anthracene
Benzo[b] chrysene
Benzo [ j ] f luoranthene
Benzo [k] f luoranthene
Benzo [g , h, i] perylene
Benzo [ a ] pyrene
Benzo [e]pyrene
Carbazole
Chrysene
Dibenz[a,h] anthracene
Fluoranthene
Perylene
Phenanthrene
Pyrene
Concentration (g/kg)
in coal tar*
(1)
2.88
6.24
0.93
0.63
1.08
1.23
2.08
1.85
1.32
2.13
0.30
17.7
0.70
13.6
7.95
(2)
4.35
6.98
0.80
0.45
1.07
1.89
1.76
1.88
1.27
2.86
0.23
17.8
0.76
17.5
10.6
*Two samples of medicinal coal tar
Source: Lijinsky et al_., 1963
-------
- 36 -
TABLE 1-8. MAJOR COMPONENTS OF GERMAN HIGH-TEMPERATURE
CONVERSION PROCESS COAL TAR
Average
Component weight percent
Naphthalene 10.0
Phenanthrene 5.0
Fluoranthene 3.3
Pyrene 2.1
Acenaphthylene 2.0
Fluorene 2.0
Chrysene 2.0
Anthracene 1.8
Carbazole 1.5
2-Methylnaphthalene 1.5
Diphenyleneoxide 1.0
Indene 1.0
Acridine 0.6
1-Methylnaphthalene 0.5
Phenol 0.4
m-Cresol 0.4
Benzene 0.4
Diphenyl 0.4
Acenaphthene 0.3
2-Phenylnaphthalene 0.3
Toluene 0.3
Quinoline 0.3
Diphenylenesulfide 0.3
Thionaphthene 0.3
m-Xylene 0.2
o-Cresol 0.2
p-Cresol 0.2
Isoquinoline 0.2
Quinaldine 0.2
Phenanthridine 0.2
7,8-Benzoquinoline 0.2
2,3-Benzodiphenyleneoxide 0.2
Indole 0.2
3,5-Dimethylphenol 0.1
2,4-Dimethylphenol 0.1
Pyridine 0.02
a-Picoline 0.02
B-Picoline 0.01
y-Picoline 0.01
2,6-Lutidine 0.01
2,4-Lutidine 0.01
Source: Shults, 1975
-------
- 37 -
phenanthrene, anthracene, pyrene, anthraquinone and chrysene(Hoiberg, 1965a).
The more complex part of coal tar pitch (30%), represented by C^, C2 and
resinoid fractions, appears to be a continuation of a series formed from
less complex, more soluble and more volatile fractions (Table 1-9), and con-
sists mostly of ring systems not highly condensed, with the majority of the
rings fused to not more than three other rings (McNeil, 1966b).
Osmotic pressure measurements have given estimates of 300 to 1000 for the
molecular weight of resinoids. The oxygen, nitrogen and sulfur content is
reported to be 1 to 1.5, 1.4 to 2.2, and 0.2 to 0.3 atoms per hundred atoms/
respectively, indicating that this fraction is largely hydrocarbons (McNeil,
1966a).
The C2 fraction is different from the resinoid fraction and is considered to
be a complex mixture of polynuclear compounds with 5 to 20 fused rings. Carbon
in the ring is the most abundant element but oxygen, nitrogen and sulfur are
also present in lesser amounts. There is a fair amount of substitution, primarily
methyl and hydroxy groups, the degree of methylation increases with molecular
weight, and the ring structure is not highly condensed.
The Cj fraction, pyridine insoluble material, is a black infusible
powder partly soluble in quinoline, appearing to have a molecular weight
range of 1500 to 2000. This C± fraction is highly variable and depends on the
type of coal and the means of production. It is thought to consist of dis-
persed particles that vary from one to two micrometers in diameter. The particles
absorb variable amounts of high molecular weight tar resins. Therefore quino-
line extracts more of the resins from the dispersed material than does pyri-
dine (McNeil, 1966a; Koiberg, 1965a).
-------
- 38 -
TABLE 1-9. PREDOMINANT STRUCTURES IN COKE OVEN TAR
Boiling Average
range percent Major components
(°C) of tar
0-150 0.8 Single 6-membered rings
Benzene
Toluene
Xylenes
150-200 3 Fused 6,5-ring systems
Indene
Hydrindene
Coumarone
200-250 12 Fused 6,6-ring systems
Naphthalene
Methyl naphthalenes
250-300 8 Fused 6,6,5-ring systems
Acenaphthene
Fluorene
Diphenylene Oxide
Source: McNeil, 1966a
-------
- 39 -
The preliminary separations described in this section are necessary
precursors to chromatographic techniques, such as gel, gas-liquid, thin layer,
gravity fed column, and high performance liquid. The chromatographic methods,
in conjuction with other analytical tools used to characterize and identify
the compounds in pitch, will be described in detail in Chapter IV.
-------
- 40 -
II - ENVIRONMENTAL EXPOSURE FACTORS: ASPHALT
A. Production and Consumption
1. Quantity produced
Asphalt sales in the United States have increased from an estimated ten
million tons in 1949 to somewhat over 34 million tons in 1974 (Asphalt Insti-
tute, 1974b). Asphalt, which constitutes 9 to 75 weight-percent of crude
petroleum, represented 4.7 percent of United States crude oil refinery yield
in 1976, only a slight increase since 1954 (Table II-l) (Nelson, 1976).
Currently, paving represents seventy-eight percent of the asphalt market,
roofing seventeen percent, and miscellaneous uses five percent (Figure II-l)
(U.S. Bureau of Mines, 1975).
The consumption of cutback and emulsified asphalts has changed little
since 1960, but the use of asphalt cements, which accounts for eighty percent
of asphalt consumed, has increased steadily to over 22 million tons (U.S.
Bureau of Mines, 1975).
Exports of asphalt were 61 thousand tons in 1972, 62 thousand tons in 1973,
75 thousand tons in 1974, and 58 thousand tons in 1975. Imports of asphalt,
including native asphalts, amounted to 1.5 million tons in 1973, 2 million
tons in 1974, and less than 1 million tons in 1975 (U.S. Bureau of Mines, 1975).
2. Market trends
Between 1902 and 1926, annual U.S. asphalt production increased from 20
thousand tons to 3 million tons (Asphalt Institute, 1974b). Annual production is
*
expected to increase from the current level of 30 million tons to over 40
million tons by 1990 (Predicasts, 1976).
Under circumstances of diminished oil supplies, asphalt will be too
valuable to use as a paving binder1, and will probably be replaced by Portland
-'•Personal communication, Walter Hubis, Gulf Mineral Resources, Denver,
Colorado.
-------
- 41 -
TASLE II-l
UNITED STATES ASPHALT PRODUCTION
AS PERCENT OF PETROLEUM REFINERY YIELD
YEAR % ASPHALT
1954 2.9
1955 2.9
1956 3.0
1957
1958 3,3
1959 3.2
1960 3.3
1961 3.4
1962 3.6
1963 3.5
1964 3.6
1965 3.7
1966 3.8
1967 3.6
1968 3.6
1969 3.7*
1970 3.6*
1971 3.8
1972 3.6
1973 3.6
1974 4.6
1975 4.4*
1976 4.7*
*Estimate
Source: Nelson, 1976
-------
- 42 -
FIGURE II-l. ANNUAL DOMESTIC SALES OF ASPHALT BY MAJOR MARKETS
28
26
24
22
C/)
£18
lie
12
10
8'
64
0
• PAVING
A ROOFING
• MISCELLANEOUS
/
A
•
i i i i I i i i i I i i i i
1955
1960 1965 1970 1975
YEARS
Source: U. S. Bureau of Mines, 1954-1976
-------
- 43 -
cement-concrete, its only current competitor. The roofing market will con-
tinue to receive its share of asphalt because no competitive substitute is
available (Gerstle, 1974).
With approximately six billion tons of asphalt covering roads, runways
and parking lots of the United States, there may be a trend toward recycling
aged asphalt. According to methods specified by Mendenhall (1976)t asphalt-
aggregate mixtures can be reheated and rejuvenated without impairing the
penetration characteristics or weakening the material.
3. Market prices
In 1950, the price of asphalt was nineteen dollars per ton. Until the
early 1970's, the price per ton fluctuated between seventeen and twenty-one
dollars. Between 1970 and 1974, the price increased to twenty-eight dollars
per ton and is expected to continue increasing (Krchma and Gagle, 1974).
4. Producers and distributors
On January 1, 1975, there were 287 crude oil refineries in the United
States with a combined distillation capacity of 15.4 million barrels per day.
Of these, 121 refineries produced asphalt (U.S. Bureau of Mines, 1976).
Economic considerations dicatate whether a petroleum residue will be processed
as an asphalt product, heavy fuel oil or petroleum coke, or burned as fuel
(Lewis, 1965).
The period of greatest asphalt consumption occurs from July through
October, with August as the month of greatest usage. Because production
usually cannot meet demand during the peak season, asphalt is often stock-
piled at the refinery or at bulk terminals which have been established to
facilitate distribution to sites of paving and roofing material manufacture
(Lewis, 1965). Asphalt is shipped from the refinery or bulk terminal by
truck, barge or rail car. ' -
-------
- 44 -
5. Production methods
Ninety-eight percent of asphalt used in the United States is derived
from crude oil (Miles, 1977) , although not all crudes are good, or even
adequate, sources of asphalt. In general, if a crude contains a residue
(fraction boiling above 399°C (750°F)) that has an API gravity below 35 and a
Watson characterization factor of less than 11.8 (i.evmore naphthenic than
paraffinic), it may be adequate for asphalt manufacture (Gary and Handwerk,
1975).
The following information concerning processes for the recovery and
refining of asphaltic residues is based on discussions by Jones (1973), Gary and
Handwerk (1975), Corbett (1966), Ball (1965), Broome (1973), Sterba (1974),
Thornton (1974), Oglesby (1975) and the Asphalt Institute (1973, 1974b).
The United States petroleum industry makes 2,347 products, of which
209 are asphalts (Table II-2) (Mantell, 1975). Asphalts from different crude
oil stocks may vary inherently in properties such as temperature susceptibility
(the amount of change is viscosity with change in temperature). Properties
such as durability may also be altered appreciably by processing treatment and
addition of fluxing oils or blending stocks.
In the refining of petroleum, crude oil is first distilled at atmospheric
pressure at temperatures up to 300° to 400°C (572° to 752°F) in order to separate
it into intermediate fractions of specific boiling ranges. After lower boiling
fractions such as gasoline, kerosine, and diesel oil are removed, the remaining
"reduced" crude, or straight-run residue, is further distilled under vacuum to
separate gas oil and lubricating oil sidestreams. The residue withdrawn from the
vacuum tower may become propane deasphalting stock or be mixed with additional
atmospheric residue for further distillation under vacuum. Sidestreams from
this third distillation may be used as catalytic cracking feedstocks, while the
-------
- 45 -
TABLE II-2. PRODUCTS MANUFACTURED BY U.S. PETROLEUM INDUSTRY
Class Number
Asphalts 209
Carbon blacks 5
Chemicals, solvents, misc. 300
Cokes 4
Distillates (diesel fuels & light fuel oils) 27
Fuel gas 1
Gasolines 40
Gas turbine fuels 5
Greases 271
Kerosines 10
Liquefied gases 13
Lubricating oils 1,165
Residual fuel oils 16
Rust preventives 65
Transformer and cable oils 12
Waxes 113
White oils 100
Source: Mantell, 1975
-------
- 46 -
asphaltic residue is removed from the tower bottom. Steam may be used during
any of these distillation steps in order to improve vaporization and minimize
coke formation in the apparatus.
Propane deasphalting is a process for removing resins or asphaltic
components from a viscous hydrocarbon fraction in order to recover lube or
catalytic cracking stocks. The charge for solvent deasphalting is derived
from atmospheric or vacuum distillation bottoms that are low in asphalt content.
The process consists of a countercurrent liquid-liquid extraction under
temperatures and pressures determined by the nature of the charge stock. The
deasphalted oil solution is withdrawn from the tower top and the propane solvent
is stripped and recycled.
Asphalt may be subjected to some form of thermal cracking which breaks
heavy oil fractions into lighter, less viscous fractions by applying heat and
pressure in the absence of a catalyst. Coking, or delayed coking, is a
severe form of cracking, at temperatures exceeding 1090°C (2000°F), which con-
verts a heavy residue into a weak coke suitable for use in the manufacture of
carbon electrodes but not in metallurgical blast furnaces. Visbreaking, at
temperatures ranging from 475° to 525°C (887° to 977°F), is a relatively mild
treatment that results in little boiling point reduction but greatly lowered
viscosity. Neither coking nor visbreaking yields asphaltic residues as does
"thermal cracking," a process now supplanted by catalytic cracking for the
production of gasoline (Corbett, 1966). Thermal asphalts result from a
cracking process in which a heavy oil stock is heated to 480° to 590°C
(900° to 1100°F), then discharged into a reaction vessel under pressures up
to 200 psig. The cracked products are distilled, leaving an asphaltic resi-
due '(Figure 11-2}.
-------
1 Ji5ttUa.tum-<
2
3
OLA.
MK
toa
-M^
U9UIDASIHAUS
Cbp iS5*-
(MC)
> CMLJLSlFft) MHIflTS
FIGURE II-2. REFINERY STEPS IN THE PRODUCTION OF ASPHALT
-------
- 48 -
Straight-run asphalts may be "air-blown" in order to produce specification
products with reduced volatile content and increased melting point (relative
to the straight-run stock). The stock is preheated to 200Vto 280°C (392°to 536°F)
and air is forced through the hot flux at rates ranging from 15 to 50 cubic
feet per minute per ton of asphalt charge. Air blowing is occasionally done
in the presence of phosphorus pentoxide, ferric chloride or zinc chloride in
order to shorten blowing time. The addition of the essentially non-recoverable
"catalyst" in concentrations from 0.1 to 3 percent results in a product with
higher penetration for a given softening point. High ductility and improved
temperature susceptibility are other advantages which lead to the use of
"catalytic asphalts" in a variety of specialty base stocks.
Asphalt cements make up eighty percent of the current asphalt market (U.S.
Bureau of Mines, 1975). These are penetration grade asphalts derived from re-
sidua of either vacuum distillation or propane deasphalting. They'may be air
blown and may represent a mixture of base stocks. Asphalt cements, cut back with
a petroleum solvent, axe either rapid-curing or medium-curing asphalts. Road
oils (slow-curing) are the least uniform of the liquid asphalts and may in fact
be directly distilled rather than cutback. Asphalt emulsions are normally
produced from 180-200 penetration asphalt cements. Depending on their intended
use, asphalts may be liquefied in various ways (Oglesby, 1975; Day and Herbert,
1965; Mertens and Borgfeldt, 1965). Blending of cutback asphalts and emul-
sified asphalts is not necessarily a refinery process (Figure II-2).
Diluting an asphalt cement with a lighter petroleum distillate yields a
product with lower viscosity. Upon evaporation of the solvent, the cured
asphalt has approximately the same penetration grade as its parent asphalt ce-
ment. The base stock may be directly blended or stored in tanks which range
-------
- 49 -
in size from 25,000 to 100,000 barrels. The stock is delivered to a blend tank
and mixed with a measured volume of diluent-
Rapid-curing cutbacks (RC) contain a diluent (gasoline or naphtha type)
with a boiling range of 104° to 218°C (220° to 425°F). The base asphalt will
vary from 70 to 100 penetration in order to leave a cured asphalt of 80-120
penetration. The least viscous grade (RC-70) can be poured at room tempera-
ture.
Middle-curing cutbacks (MC) use a kerosine type diluent with a boiling
range of 135° to 302°C (275° to 575°F). This cutback is more versatile
than the others, with good wetting properties on fine aggregates and a moder-
ate evaporation rate. The base asphalt will vary from 70 to 250 penetration
to leave a cured residue of 120 to 250 penetration. MC-30 and MC-70 can be
poured at room temperature. MC-70 can contain as much as 40 percent by volume
diluent. The most viscous grade, MC-3000, may have as little as 18 percent
solvent and usually must be warmed before use.
Slow-curing asphalts (SC), often referred to as "road oils," may be refined
directly to grade rather than consisting of an asphalt cement plus diluent.
They are the least uniform in composition. Heavy diesel fuel, overhead gas oils
or cycle stocks from other processes may be used as solvents. The lightest grade
(SC-70) has the consistency of light syrup. The heaviest grade (SC-3000) will
scarcely deform at room temperature, and is slightly less viscous than the
softest asphalt cement (200 to 300 penetration).
Aqueous emulsions in which the asphalt content is 55 to" 70 percent by
weight are another form of liquefied asphalt. The three emulsion grades -
rapid-setting, medium-setting, and slow-setting - can be applied at normal
temperatures. The asphalt cures by evaporation of the water rather than of a
petroleum solvent, thus avoiding hydrocarbon emissions. Emulsions can be
-------
- 50 -
applied on wet aggregates and generally are ready to resist traffic damage
sooner than cutbacks. The equipment needed for mixing and application is
simpler and less expensive than that required for other asphalt products.
Before 1957, anionic emulsions vrere the only type commercially available.
Saponified fatty and resinous acids or saponified tallow derivatives were the
emulsifying agents used with an asphalt cement of 180 to 200 penetration.
Cationic emulsions, using a quaternary ammonium compound as an emulsifying
agent^ are now available and can be used with a wide variety of mineral ag-
gregates. They adhere well to wet aggregates, and can be used under condi-
tions of high humidity or low air temperatures.
B. Uses
Asphalt is a readily adhesive, highly waterproof, durable thermoplastic
material, resistant to the action of most acids, alkalis and salts. These
properties are utilized in a wide variety of applications.
1. Major uses
a. Paving
CD Production and consumption
The Standard Industrial Classification (SIC) category SIC 2951 includes
964 establishments manufacturing asphalt (in some cases, coal tar) paving
mixtures as well as blocks of asphalt, coal tar, or creosoted wood. Of these
964, 889 had seventy-five percent specialization (defined as the ratio of all
primary products to the total of primary plus secondary products). About 10,000
production workers are classified under SIC 2951 (U.S. Bureau of Census, 1975)
(Table II-3). The top ten paving mix producers according to 1974 production
figures are listed in Table II-4.
The value of all paving mixtures and blocks shipments classified under SIC
2951 was $265.9 million in 1950, $561.9 million in 1968 and $893.4 million in
1972. The amount of asphalt of less than 200 penetration consumed in 1967 by
-------
- 51 -
TABLE II-3.
EMPLOYMENT SIZE OF ESTABLISHMENTS (SIC 2951)
PAVING MATERIALS
Total
964
Establishments with an
average of—
1 to 4 employees
5 to 9
10 to 19
20 to 49
50 to 99
100 to 249
250 to 499
500 to 999
1000 to 2,499
347
286
163
117
34
13
2
1
1
Source: U. S. Bureau of Census, 1975
TABLE II-4. THE TOP TEN PAVING MIX PRODUCERS: 1974
Producer and home state
The General Crushed Stone Co., Pa.
L.M. Pike & Sons, Inc., N.H.
The Interstate Amiesite Corp., Pa.
Asphalt Products Corp., S.C.
Broce Construction Co., Okla.
Associated Sand & Gravel Co., Inc., Wash.
Ajax Paving Industries, Mich.
Western Engineering Co., la.
Dickerson, Inc., N.C.
Highway Materials, Inc., Pa.
Plant mix tonnage
1,500,000
1,334,545
1,000,000
989,000
847,214
843,110
800,000
800,000
750,000
750,000
Source: Roads and Streets, 1975
-------
- 52 -
the paving industry was 4,761,400 tons with a delivered cost of $104.5 million.
In 1972, 5,410,000 tons were consumed at a cost of $157.9 million (U.S. Bureau
of Census, 1975).
(2) Materials
Currently, ninety-four percent (over 1.7 million miles) of the paved
surfaces, in the United States are bituminous (Oglesby, 1975). These bituminous
surfaces range from dirt surfaces lightly sprayed with liquid asphalt to high-
grade asphalt cement pavements.
A finished paving mix consists of about six percent asphalt cement and
ninety-four percent mineral aggregates. In addition to asphalt cement, a
variety of cutback and emulsified asphalts are used to treat or finish roads
(See Section II.A.5. for descriptions of asphalt cements, cutbacks and emulsions)
Approximately 700 million tons of mineral aggregates are consumed annually
for all aspects of highway construction. Slag, broken stone, gravel and sand,
the aggregates most commonly used, constitute 75% by volume of a finished paving
mix. Because aggregates vary greatly in composition, strength, porosity and
surface roughness, specifications and tests have been developed to insure cer-
tain minimum standards (Oglesby, 1975).
Experimental pavements using asphalt-rubber mixtures have been laid in many
states. Rubber enhances the coefficient of friction, improves the stability of
paving mixtures, and reduces temperature susceptibility and brittleness, as
well as imparting greater elasticity and extending pavement life (Oglesby, 1975).
Other experimental pavements have been laid using an epoxy resin and asphalt
binder which is resitant to wear, heat and the solvent effects of fuel (Hoiberg,
1965) .
-------
- 53 -
(3) Process descriptions
Hot mix plants
General information in the following section was obtained from Oglesby
(1975).
Although road surfaces can be treated with either hot or cold applied asphalt,
hot treatments are the most common. It is estimated that there are 4500 pav-
ing plants of all sizes in the United States; plants with a capacity of 600
tons per hour of finished mix are common near most large cities (Puzinauskas
and Corbett, 1975).
Asphalt is loaded at the refinery or bulk terminal at elevated temperatures
into steam heated tank cars, trucks or drums and transported to the hot mix
plant. The asphalt, stored in large heated underground tanks, can be pumped
directly to the platform on which finished asphalt-aggregate mixtures are
produced.
The mineral aggregates are sent through the drier, a firebrick lined
steel cylinder, to drive off moisture and heat to a mixing temperature of
149° to 160°C (300° to 320°F). The hot aggregates are segregated by size through
shaking screens.
In batch-mixing processes (the most common), aggregates and the asphalt
binder are mixed by revolving blades in pug mills that can reach capacities
of sixteen tons or more. The finished mix is deposited into waiting'trucks
and taken to the job site.
High capacity plants use a process whereby hot binder is introduced directly
into the drier, thus insuring continuous output of finished product. Exposure
of the binder to drier conditions does not seem to accelerate its aging, and
the problem of dust from fine aggregates is substantially reduced.
-------
- 54 -
Cold mix plants
Cold mix plants are similar to hot mix plants in operation, except that
the aggregates are cooled before being coated with a naphtha liquefier. The
coated aggregates are mixed with hot asphalt binder to form the finished pav-
ing product. Such cold mix products are not in common use.
Paving
In the past, all placing and leveling of hot asphalt was performed
manually. Self-propelled finishing machines have largely supplanted manual
operations, although small jobs, especially patching operations in cities,
still rely on hand equipment. The hot aggregate-asphalt mixture, which is
transported to the job site in dump trucks, is unloaded, spread and tamped,
usually with one machine. Final tamping is done by large, smooth-wheeled
rollers.
Road mix processing, still used on side roads, is performed with a single
machine that picks up aggregates, either freshly laid or pulverized from the
old surface, mixes them with asphalt cement and spreads the new pavement.
Surface treatment
Road surfaces are treated with a pressurized distributor truck (800
to 5500 gallon capacity) from which liquid asphalt is forced through a spray
bar approximately twenty feet long.
Several types of surface treatments may be used:
1) Dust palliatives: light slow-curing road oil or slow-setting emulsions
applied at 79°C U75°F).
2) Prime (tack) coats: light medium-curing cutbacks or light road tar or
slow-setting emulsions.
3) Armor coats on macadam or low quality concrete: varies with surface
-------
- 55 -
4) Seal coats: Hand or crushed stone mixed with a slow-setting road
oil applied to damp pavement. Slow-setting emulsions are sprayed on to
rejuvenate surfaces.
Proper temperatures of application, as well as ambient temperature,
are fundamental to good asphalt performance. State highway departments
specify minimum air temperatures for laying asphalt ranging from 0°C (32°F)
to 15.6°C (60°F), the usual being 4.4°C (40°F). (Table II-5) .
b. Roofing
(1) Production and consumption
In 1972, there were 236 plants in classification SIC 2952; which includes
establishments that manufacture asphalt and coal tar saturated felts in roll
or shingle form, as well as roofing cements and coatings (U.S. Office of
Management and Budget, 1972). Of the total 236, 215 had seventy-five percent
or more specialization (U.S. Bureau of Census, 1975). (Specialization is
defined as the ratio of all primary products to the total of primary plus
secondary products). There were 11,500 production workers classified under
SIC 2952 in 1972 (U.S. Bureau of Census, 1975) (Table II-<5) .
Illinois, California, Texas, New Jersey, Ohio and Pennsylvania each
have over ten roofing plants. Total sales of the plants in these states
in 1973 were $474 million; total sales for the United States were $881
million (Gerstle, 1974).
The value of all shipments of asphalt and pitch roofing "coatings and
cements" (SIC 2952-2) was $67.9 million in 1958, $124.5 million in 1968 and
$155.3 million in 1972 (U.S. Bureau of Census,1975). The value of all ship-
ments of asphalt and pitch "roofing and siding" products (shingles, felt rolls)
-------
- 56 -
TABLE II-5. SUGGESTED MIXING AND APPLICATION TEMPERATURES
FOR ASPHALTIC MATERIALS
Type and grade Spraying temperature
of material Pugmill mixing temperature (surface treatment)
ASPHALT CEMENTS
40/50
85/100
200/300
°C
134-177
124-163
107-]49
°F
275-350
255-325
225-300
°C
149-210
143-204
134-196
oF
300-410
290-400
275-385
CUTBACK ASPHALTS
RC,MC,SC
70 35-60 95-140 49-107 120-225
800 74-96 165-205 93-169 200-305
3000 93-116 200-240 113-119 235-245
EMULSIFIED ASPHALTS
MS-2 CMS-2 10-*77 50-170 38-71 100-160
SS-1 CSS-1 10-77 50-170 24-54 75-130
Source: Oglesby, 1975
-------
- 57 -
TABLE 11-6
EMPLOYMENT SIZE OF ESTABLISHMENTS
(SIC 2952) ROOFING MATERIALS
Total 236
Establishments with
an average of—
1 to 4 employees 33
5 to 9 26
10 to 19 36
20 to 49 52
50 to 99 31
100 to 249 50
250 to 499 6
500 to 999 2
Source: U.S. Bureau of Census, 1975
-------
- 58 -
(SIC 2952-3^ was $313.6 million in 1958, $385.9 million in 1968 and $690.6
million in 1972 (U.S. Bureau of Census, 1975).
In 1967/ manufacturers classified under SIC 2952 consumed 9.1 million
barrels of 200 and less penetration asphalt; by 1972, consumption increased
to 12.8 million barrels. Consumption of 200 and over penetration asphalt
was 27.6 million barrels in 1967 and 41.1 million barrels in 1972 (U.S. Bureau
of Census, 1975),
Although coal tar and coal tar pitch are still used in the roofing trade,
there has been a trend of increasing use of asphalt. For example, 864,000
tons of asphalt saturated felt were shipped in 1967, compared to 46,000 tons
of tar saturated felt; in 1972, asphalt felt shipment increased to 871,500 tons,
while shipments of tar saturated felt declined to 36,500 tons (U.S. Bureau of
Census, 1975).
(2) Products and materials
The information in the following section was obtained from Gerstle
(1974) and Berry (1968).
Bitumens (asphalt or tar), fillers or mineral coatings, and felts or
woven fabrics are the three major raw material classes used in the "asphalt"
roofing industry. Major products include roll roofing, siding, shingles,
saturated felts, and bituminous adhesives and cements.
Roofing grade asphalts are air blown to certain softening point
specifications. The normal range of softening points for saturant grade as-
phalts is 38° to 60°C (100° to 140°F) , for roofing cements 63° to 82°C
(145° to 180°F) , and for coating grade asphalt 93° to 107°C (200° to 225°F) .
Mineral granules such as sand or asbestos used on felt rolls and cut
shingles must be dust-free, opaque to sunlight and bondable to the asphalt
-------
- 59 -
coating. Approximately 700 pounds of granules are used per ton of finished
material.
Felts of cloth, paper or asbestos are formed on machines similar to those
used in the manufacture of paper. Woven fabrics such as burlap, hessian or
duck are also used; these materials, however, do not take up as much saturant
as pressed felts.
Bituminous adhesives are used on built-up roofs subjected to wide tempera-
ture fluctuations and in construction of above or below ground membrane water-
proofing on bridges, culverts, tunnels or foundations. Asphalt putty or bi-
tuminous cements are prepared to troweling consistency and are used for repair
of metal and composition roofing, for damp proofing and minor waterproofing.
(3) Process descriptions
The following section is based on information from Berry (1968) and Gerstle
(1974) .
Composition roofs are either "built-up" or "prepared." Built-up roofs
are essentially manufactured on the job, assembled by alternating layers of
asphalt or tar saturated felt and soft bitumen. Shingles are considered
"prepared" roofing. Both types of roofs consist of a structural felt saturated
with bitumen and finished with a hard bitumen coating embedded with mineral
granules.
Prepared roofing material
Production of saturated felt to wind in rolls or cut into shingles is
the primary operation of roofing mill processes.
Standard weight felts (15, 30, and 55 pounds per 48 square feet) are run
through saturator tanks filled with hot asphalt (232° to 260°C (450° to 500°F))
on loopers running at average speeds between 250 and 400 feet per minute.
-------
- 60 -
Saturation with hot bitumen fills voids in the felt, binds the fibers, and
primes the material for an outer protective coating.
After cooling and drying, the saturated felt is coated with a bitumen
relatively harder than that used in saturation. If smooth roll roofing is
being manufactured, the saturated felt or fabric is covered with a parting
agent such as talc, mica, slag or sand (approximately 3 to 5 pounds per 100
square feet of felt) which is applied to facilitate separation of layers.
Mineral granules are embedded into the top coating with hot press rollers
(107° to 135°C (225° to 275°F)). A parting agent is applied to the back and
the material is either rolled or cut into shingles.
Built-up roofing
Large, low-slope roofs on buildings such as warehouses and large apart-
ment complexes are often built up. The roof is assembled using bitumen-
saturated felt and cold-process cement or roofing asphalts having a softening
point of 57° to 93°C (135cto 200°F).
Hot-applied systems utilize alternating layers of standard roofing felt
and bitumen. The bitumen is usually in solid blocks that must be chopped and
heated. The first layer of felt is spread and mopped with hot bitumen.
Depending on the size and complexity of the job, subsequent layers are placed
manually and sealed or put down with a felt machine that spreads heated bitumen
and rolls out felt in a single operation.
A prefabricated cap sheet (felt-surface with mineral granules) is laid,
or the granules may be embedded on site using an asphalt spreader followed
by a rock spreader.
Cold-applied roofing materials are used when the standard heating kettle
of hot-applied systems is dangerous or impractical. The cold-process cement
-------
- 61 -
adheres to the felt and the cement solvent.(usually a 149° to 204°C.(300° to
400°P) boiling range naphtha) evaporates through it. Within 24 hours of
assembling, the roof is waterproof.
2. Minor uses
The following section is based on information obtained from Hoiberg et al.
(1963), Hoiberg (1965a,b) and Asphalt Institute (1973, 1974a).
The value of asphalt in waterproofing, cementing, and providing protective
coatings has been known at least five thousand years. In the Mesopotamia
and Indus Valley regions (ca 3500 BC) asphalt was used for paving, building,
as a wood protectant and in waterproofing enclosures. The Egyptians used
asphalt in mummification.
The uses today classified as "minor" or "miscellaneous" are nonetheless
significant, both in terms of value and diversity.
Asphalt is compatible with a variety of fillers. Styrene-butadiene
rubber, tire buffings, neoprene and reclaimed rubber have all been used in
mixtures with asphalt to produce caulking compounds, joint sealants, cable
coatings, shoe soles, and sound insulation panels, as well as paving mixes.
Asphalt and polyepoxides (polyglycidal ethers) produce mixtures of excel]ent
chemical and solvent resistance. Pavements, surface treatments, and protective
coatings for tunnels and bridge abuttments are often asphalt-epoxy mixtures.
Polyvinyl chloride, methacrylic resins, polybutenes and polybutadienes, coumarone
resin and mineral rubber (gilsonite) are other additives that improve the
performance of asphalt.
Asphalt compounds are widely used in hydraulic engineering and erosion
control. In conjunction with highway construction and maintenance, both
asphalt and coal tar pitch are used for soil stabilization and bank erosion
control. Dam linings and sealants, canal linings and sealants, catchment
-------
- 62 -
basins, dike protection, levee stabilization, ditch linings, sand dune
stabilization, sewage lagoons, swimming pools and waste ponds are other
applications for asphalt in hydraulic engineering.
Asphalt has a variety of uses in the construction trade: building blocks,
bricks, sidings, floor tiles, insulation, putty, damp proofing, varnishes,
plumbing pipe coatings, paint compositions, joint fillers and building papers.
Because of its low electrical conductivity, asphalt is utilized in such
products as insulating tapes, wire coatings, transformer potting compounds,
capacitor seals, molded conduits and battery sealants.
Asphalt is an effective sealant for containing wastes of low or intermediate
radioactivity (Christenson, 1968).
Bitumens have been used as a stable matrix to which fertilizers, pesticides
and rodent repellents are added for slow release uses in fields, road banks
or on trees.
Other products in which asphalt may be found are clay pigeons, foundry cores,
graphite and electrode binders, linings for burial vaults, embalming compositions,
printing inks, paper water proofing, tree paints, mulches, automobile undersealants,
briquette binders, marine enamels, mirror backings and imitation leather.
3. Alternatives to the use of asphalt
Currently the paving industry is dominated by asphalt: ninety-four
percent of the paved roads in the United States are covered with asphalt; only
six percent with Portland cement-concrete (PCC) (Oglesby, 1975). Often
highways of PCC are laid, then paved with asphalt when resurfacing is required!.
Coal tar pitch, is also available as a replacement for asphalt in paving binders.
•^Personal communication, Ralph Cannon, U.S. Occupational Safety and Health
Administration, Cincinnati, Ohio.
-------
- 63 -
Although the current roofing market is dominated by asphalt products, there
are widely used substitutes,, Pitch has been used for years and has, from an
engineering standpoint, performed well; materials such as sheets of
neoprene, silicone rubber, polyvinyl chloride, polyvinyl fluoride, chloro-
sulfonated polyethylene and ethylene polypropylene terpolymers have received
attention as potential roofing products. Liquid forms of some of these materials
have been used with glass fiber mats, polymer bonded asbestos felt and polyure-
than foam. Metal roofs of galvanized iron or corrugated aluminum have been
used in the South. Slate, tile and wood shingles have had periods of popular
use. Asbestos-cement, formed of long asbestos fibers, portland cement and fine
silica, is a durable, low maintenance roofing that was popular in the middle
nineteenth century.
The tar from plastics pyrolysis has a much lower PAH content than asphalt
and can be fashioned into a good, serviceable substitute for asphalt (Baum and
Parker, 1974). How much work is being done in this area is uncertain.
Other than coal pitches, which may increase in availability as petroleum
supplies diminish and coal conversion is expanded, a universal replacement
for asphalt will probably not be found. Faced with choices of substitutions,
the versatility and overall value of asphalt, known for over 5000 years, is
apparent.
C. Environmental contamination potential
1. Controlled and uncontrolled emissions
a- Air blowing
Of seventy-six roofing companies surveyed by the Midwest Research Institute,
82 percent purchased asphalt air blown at the refinery. The thirteen companies
that processed their own asphalt all had thermal afterburners (fume incinerators)
as air pollution control devices. Refinery air blowing operations, by and large,
-------
- 64 -
also have some variety of fume incinerator as a control device (Gorman, 1976).
At one time, blowing was done primarily in horizontal cylindrical tanks
(stills). The conversion to vertical tanks has resulted in reduced emissions
because of the shorter blowing time required. Losses of asphalt from horizontal
stills have been estimated from 3 to 5 percent of the total amount blown; losses
from vertical stills are between 1 and 2 percent (Gerstle, 1974).
Rate of air flow, temperature, phase of the blowing cycle, sulfur content
of the asphalt, softening point of the asphalt and duration of the operation
all influence overall emissions. A high-melting asphalt, for example, requires
a longer blowing time, thus producing a greater amount of particulate emissions.
Air blowing emissions may contain water vapor, carbon monoxide, carbon
dioxide, sulfur and nitrogen oxides, hydrogen sulfide, aldehydes, entrained
asphalt droplets and polycyclic aromatic hydrocarbons (Kratky, 1968; Jones,
1973; Gerstle, 1974).
About 0.0008 to 0.0019 percent of the particulate emissions may consist of
PAH (Gerstle, 1974). PAH isolated from air blowing emissions include benzo(c)-
phenanthrene, benzo(a)pyrene, benzo(e)pyrene, 7,12-dimethylbenz(a)anthracene,
dibenz(a,h)pyrene, dibenz(a,i)pyrene, pyrene, anthracene, phenanthrene and
fluoranthene (Gerstle, 1974,-von Lehmden et aJU, 1965).
Emission control
The primary -method of control for air blowing operations is the thermal
afterburner (fume incinerator). For optimal operation the effluent gas
should be retained in the incineration chamber from 0.3 to 0.5 seconds. For
%
90 percent control the minimum chamber temperature should be 750°C; 99 percent
control can be achieved with a chamber temperature of 816°C (Jones, 1973;
Gerstle, 1974). Afterburners in operation currently raise temperatures from
538°C to 1090°C (Gorman, 1976).
-------
- 65 -
Afterburners may be used in conjunction with scrubbers. In this case,
the effluent from the afterburner flows through an oil-water gravity separator
and then to the scrubbing unit. The oil may be removed and burned as fuel or
reprocessed (Jones, 1973). The gases from the scrubber are vented to the
atmosphere.
Several other control methods are potentially available to contain emissions
from asphalt airblowing. Catalytic fume burners are not recommended because
entrained asphalt droplets in the effluent gas clog the catalyst (Jones, 1973;
Gorman, 1976). Dry electrostatic precipitators are also difficult to maintain
because asphalt droplets foul the filters (Gerstle, 1974; Gorman, 1976). Wet
electrostatic precipitators can give 99 percent control; however, the water must
be processed before disposal (Gerstle, 1974; Gorman, 1976). High energy air
filters are unable to control gaseous emissions or odors but can collect 98 per-
cent of the particulate emissions and are easy to maintain (Gorman, 1976) .
b. Roofing mills
Forty-eight percent of roofing plants (SIC 2952) are located in cities
with populations of over 100,000; the six largest plants account for 20 per-
cent of the total production of roofing materials. Poorly controlled emissions
thus could contribute to the general air pollution burden of many urban areas
(Gerstle, 1974).
Asphalt roofing plants are often characterized by a hazy, odorous
atmosphere in and around the plant, Unless air blowing (see preceding
section) is done at the plant, the major source of emissions is the saturator
tank. Sulfur compounds, aldehydes, carbon monoxide, water vapor, gaseous
hydrocarbons and entrained asphalt droplets are usually present. PAH may
be a problem from the saturator tank or the hot asphalt storage tanks.
Inorganic particulates from the sand (mineral granule) drier, the coating
-------
- 66 -
mixer or application of the parting agent commonly contribute to the hazy
atmosphere (Gerstle, 1974).
The saturator tank is ordinarily somewhat enclosed by a hood, which may
vent directly to the atmosphere or to a control device similar to those used
for air blowing emissions. If particulate emissions are present, fabric filters
can be installed (Gorman, 1976).
Roofing kettles
Thermal cracking caused by hot spots in roofing kettles (reaching 538°C
near the blast burners) is responsible for the dense white vapors that are
often associated with roofing operations. According to a study by Thomas
and Mukai (1975), maintaining an even kettle temperature of less than 260°C
will eliminate all apparent emissions. The study recommends that granular
asphalt be introduced into the kettle through an interlock system, rather
than removing the kettle lid, and that an afterburner (fume incinerator)
be installed on the exhaust duct.
c. Hot mix plants
There are approximately 4500 hot mix plants in the United States,
producing 350 million tons of finished paving mix annually (Puzinauskas
and Corbett, 1975). These plants contribute over 31 thousand tons of
particulates to the atmosphere each year. This represents less than 0.01
percent of the nation's particulate inventory (Pit and Quarry, 1972). The
major source of particulate emissions from hot mix plants is the aggregate
drier; quantities up to 6700 pounds per 182 tons of finished wix have been
reported. Combined particulate emissions from other sources - aggregate
elevators, aggregate separating screens and pugmill mixers - are three or
four times less (Danielson, 1973).
-------
- 67 -
Untrained particulate material in the uncontrolled effluent gas stream
may represent four to eight percent of the weight of the mineral aggregate being
dried (Pit and Quarry, 1972). When mineral filler 74 micrometers or less in
diameter is being dried, up to 55 weight-percent of the material may be lost
to the effluent gas stream (Danielson, 1973). Particulate matter in the
uncontrolled emissions ranges up to 100 pm in diameter, with almost 70 percent
by weight associated with particles less than 74 lorn and 20 percent with par-
ticles less than 5 um (U.S. Environmental Protection Agency, 1975a).
Hot mix plant exhaust gases that meet federal air pollution standards
contain few particles larger than 40 ^im; the majority range in size from 0.1 to
10 jjm (U.S. Environmental Protection Agency, 1975a).
In addition to particulates, emissions from hot mix plants can contain
carbon monoxide, nitrogen oxides, sulfur dioxide, hydrogen sulfide, carbonyl
sulfide, aldehydes, phenol, polycyclic aromatic hydrocarbons and metals
(Puzinauskas and Corbett, 1975). PAH isolated include pyrene, benz(a)anthracene,
anthracene, benzo(a)pyrene, benzo(e)pyrene and perylene (Puzinauskas and Corbett,
1975; von Lehmden ejt aJU , 1965),
Metals in asphalt tend to remain associated with the high molecular
weight, relatively nonvolatile organic complexes; thus they can be expected
to remain in the finished mix. Low concentrations, however, of cadmium, lead,
nickel, and vanadium have been detected in asphalt plant emissions (Puzinauskas
and Corbett, 1975). In a study by Klein (1972) an "asphalt plant" (unspecified
products) was implicated as the source of mercury, at levels ranging from 0.15
to greater than 0.3 ppm, found in the soil of an area of woodlands and fruit
orchards.
-------
- 68 -
Control methods
The federal standards for asphalt hot mix plants (40 CPR 60.11) limit
particulate emissions to less than 90 milligrams per dry standard cubic meter
(mg/dscm) and opacity to less than 20 percent (U.S. Environmental Protection
Agency, 1974).
The collection efficiency of most cyclone systems used for control of
hot mix plant effluent gases varies from 70 to 90 percent for most particle
sizes (Panielson, 1973). A wet scrubber (centrifugal or high energy wet
venturi) or fabric filter can be added to the cyclone sytem to increase
control efficiency up to 99 percent (Danielson, 1973). Water from the
scrubbers may be contaminated with mineral particles (less than 74 urn) , clay
particles, sulfuric acid (depending upon type of fuel used to fire drier),
gasoline, oil or asphalt (Asphalt Institute, 1974 b).
d. Paving
Preparation of cutback asphalts and conditions of use have been discussed
in Sections II.A.5. and II.B.I.a.(3).
Approximately four percent - 655,000 metric tons - of the volatile
organic compounds emitted annually from all U.S. stationary sources have been
attributed to the use of cutback asphalts. Although the mixing and trans-
porting of liquified asphalts contributes to emissions, road surfaces are the
major source. It has been estimated that substitution of emulsified asphalts
(water and asphalt) would reduce volatile organic compound emissions from
paved surfaces by 100 percent. States that have begun substituting emulsions
for cutbacks have reported few problems or major expenses associated with the
transition. No significant solid or liquid wastes result from usage of emulsions
(U.S. Environmental Protection Agency, 1977; Kandahl, 1974).
-------
- 69 -
2. Contamination potential of asphalt transport and storage
There are no available estimates of the actual or potential contamination
from the transport of asphalt or its products. According to 1972 figures,
over 70 percent of asphalt paving and roofing products, solid and liquid, are
shipped distances between 300 and 999 miles. Of that percentage, 65 percent
are loads exceeding 45 tons shipped primarily by water, secondarily by rail.
More than 20 percent of asphalt loads are 15 to 30 tons shipped by truck
tU.S. Bureau of Census, 1976). Liquid asphalt is shipped in specially de-
signed trucks, heated rail cars or barges.
There are few estimates of contamination potential due to storage of
asphalt. Liquid asphalt is maintained in tanks of various sizes at temperatures
of 178° to 232'C (350° to 450°F). Emissions are variable and depend, in part,
on storage temperature, asphalt composition and frequency of filling. Recently
constructed tanks minimize hydrocarbon emissions and, although many are vented
to the atmosphere, some are attached to thermal afterburners (fume incinerators)
(Gerstle, 1974).
Samples of vapors displaced during a filling operation of hot storage
tank showed nitrogen (67.3%), oxygen (13%), carbon monoxide (1.4%), water
(18.2%) and traces of methane, ethane and argon. An estimate of possible
hydrocarbon displacement, assuming a molecular weight of 120, is 0.01 pounds
of hydrocarbon per ton of asphalt (Gerstle, 1974).
3. Contamination potential from disposal
How much asphalt is actually "thrown away" is not known. According to
Mantell (1975), asphalt containing oil bottoms or not meeting specifications
is buried in gulleys or landfill areas.
Much of the refinery waste of 20 or 25 years ago is now being processed
into marketable goods or has been eliminated by alternative processes. Waste
-------
- 70 -
that is generated is still most commonly buried in landfill areas. Quality
control of these operations is variable, depending upon the individual
circumstances (Rosenberg et al., 1976).
The most tangible contribution of asphaltic residues to the environment
is metals or organometallic complexes. Metals potentially present in as-
phalt waste are vanadium, nickel, iron, copper, small amounts of cadmium,
cobalt, lead, molybdenum and mercury. An estimate of contamination by these
metals from waste asphalt is not available (Rosenberg et. al^., 1976).
4. Environmental contamination potential from use
Large surface areas of asphalt remain constantly exposed to the environ-
ment. Aside from emissions and effluents from the manufacture of asphalt
products, many uses provide potential sources of contamination: roads, soil and
shoreline stabilizers, weatherproof coatings on foundations, tunnels, and
bridges, dam and reservoir linings and pipe coatings.
The question of whether roads paved with asphalt are a source of poly-
cyclic aromatic hydrocarbons, and thus pose a potential health threat, has not
been resolved. According to studies by Neukomm et al. (1975) and Just et
al. (1971) there were no discernible differences in the concentration of PAH iso-
lated from air and dust near roads paved with asphalt and roads paved with con-
crete. Neither study specified the exact composition of the "asphalt" high-
way. Waibel (1976) concluded that "bitumen" highways (13% coal tar pitch and
87% asphalt) are a significant source of benzo(a)pyrene. Contrasting a con-
crete and a bitumen highway of similiar traffic flow, Waibel (1976) found that
dust generated from the bitumen pavement had over three times the BaP con-
centration (15 mg per one meter length of two lane road in winter; 10 mg in
summer) of dust generated from the concrete. The majority of BaP was associ-
ated with particles between 15 and 30 micrometers in diameter.
-------
- 71 -
5. Weathering and microbial degradation
Many of the major uses of asphalt are based on its permanence and
persistence under conditions of prolonged exposure of large surface areas to
the environment. Paving and roofing materials are constantly exposed to heat,
light, water, wind and atmospheric oxidants. Road-building material are sub-
ject, in addition, to mechanical stress and abrasion by vehicular traffic and
to the leaching effects of ice control chemicals. Waterproofing compounds and
weatherproofing sealants may be constantly exposed to fresh or saline water.
Transformation of the physical structure of asphalt by heat, light,
intermittent freezing, traffic stress, and erosion exposes additional surface
area to the effects of weathering. Under these conditions, asphalt may be
broken into particles small enough to be transported by wind and water.
Weathering products of interest because of potential health effects include
polynuclear aromatic hydrocarbons - including heterocyclic compounds as well
as PAH - and trace metals. The contribuition of asphalt to the environmental
load of polynuclear hydrocarbons and metals has not been examined.
Weathering
In paving materials, the primary cause of surface hardening seems to be
volatilization or polymerization of the asphalt binder. In roofing asphalts,
mechanical stress due to thermal shock results in surface cracks that signal
failure; sunlight may catalyze the polymerization that is responsible for
brittleness and subsequent cracking (Wright, 1965; Berry, 1968) .
Oxidation, a primary weathering process that affects asphalt, results in
the loss of water, carbon dioxide and volatile organic compounds. The asphal-
tene content of asphalts increases after oxidation, probably due to oxidation of
oils. Formation and subsequent loss of water-soluble and volatile compounds
result in weight reduction of the asphalt. The hardening following oxidation may
be due to the conversion of resins to asphaltenes and oils to resins (Wright, 1965)
-------
- 72 -
Although exposure of asphalt to oxidants other than 02 accelerates aging,
it is difficult to ascertain the impact of such prevalent air pollutants as ni-
trogen oxides, peroxides, sulfur oxides and ozone on the aging or degrada-
tion of asphalt (Wright, 1965). The use of antioxidants to retard asphalt
aging has been proposed. Additives that decompose peroxides extend dura-
bility and retard asphalt weight loss (Wright, 1965).
Tests in which paving asphalts were exposed to heat in the absence of
light, the presence of ultraviolet and the presence of infrared, suggest that
light may have a substantial effect on asphalt performance. Under ultraviolet
light, large decreases in penetration and increases in softening point occurred.
The infrared exposure produced changes intermediate between the conditions of
no light and of ultraviolet light (Vallerga et al., 1957).
Traxler and Scrivener (1971) implicated trace metals as catalysts in the
hardening of asphalt observed after exposure to sunlight.
Exposure of asphalt to water accelerates aging of asphalt materials,
probably due to the loss of water-soluble compounds, with subsequent exposure
of a fresh surface to the elements. It has also been observed that asphalt
degradation is hastened by increased humidity (Wright, 1965). Pure asphalt
has a limited solubility in water, in the range of 0.001 to 0.01 percent;
commercial asphalts, however, vary in their water absorption capacity depending
on the presence of water-soluble salts or absorbing fillers such as gypsum,
the use of catalysts in air-blowing, and the origin and hardness of the as-
phalt itself.
Although roads are subjected to mechanical stress, failure of the as-
phalt is due to increasing brittleness caused by volatilization and oxidation
followed by polymerization. Failure of roofs is caused to a great extent by
-------
- 73 -
mechanical stress: during weathering, the asphaltene fraction increases at
the expense of the oils and resins, resulting in insufficient oil to sus-
tain the plastic structure of the asphaltenes. Severe cracking occurs,
hastened by thermal shock and ultraviolet light (Wright, 1965}.
Microbial degradation
All bitumens are potentially susceptible to biological degradation to
some degree. Most bitumens, in fact, whether manufactured or naturally
occurring, are attacked to some extent by a variety of microorganisms. It
is difficult to ascertain the degree of damage to manufactured products
or the extent of decomposition of native deposits, as well as the number
and diversity of organisms capable of hydrocarbon utilization. A partial
list of bitumen utilizers includes Thiobacillus denitrificans, Mucor spp,
Pseudomonas spp, Micrococcus spp, Bacillus spp, Alcaligenes spp, Mycobacterium
spp, Chromobacter spp, and Flavobacterium spp (Traxler, 1964).
Asphaltic components of crude oil can be assimilated by microorganisms
under aerobic and anaerobic conditions, yielding, for example, hydrogen sul-
fide and asphaltenes (Atlas and Bartha, 1973). The effect of bacteria on
asphalt viscosity has been studied by Traxler et al.(1964). Brunnock et al.
(1968) have reported that residual oils, after degradation, have higher vis-
cosities and increased asphaltene content, but unchanged paraffin profile and
content of vanadium and nickel. The increase in asphaltenes as a result of
microbial degradation of crude oil has also been reported by Walker et a.1.
(1975a,b) and Jobson ejt al. (1972). It has been suggested that the observed
increase in asphaltenes, a mixture of polar, pentane insoluble compounds,
may arise from the production of extracellular compounds such as carboxylic
acids, esters and ketones.
Four species of fungi (Cephalosporium acremonium, Penicillium spp,
Cunninghamella elegans, and Aspergillus versicolor) were tested for their
ability to utilize an asphaltic base crude and a paraffinic base crude. After
-------
- 74 -
five days of growth in a medium containing basal salts plus crude oil, over
90 percent of the paraffinic crude had been assimilated. However, less than
half that amount of asphaltic base crude had been utilized (Cerniglia and
Perry, 1973).
Walker e_t al_. (1975a,b) investigated the ability of an achlorophyllous
alga, Prototheca zopfii, to degrade motor oil and a Louisiana crude. After
thirty days, ten percent of the motor oil and forty percent of the crude oil
had been degraded. The asphaltene and resin content of the motor oil increased,
whereas these fractions decreased in the crude oil.
As a result of weathering and biological degradation, asphalt may release
metals, organometallic complexes, polycyclic and heterocyclic hydrocarbons to
the soil, air or water. The potential impact of metals such as vanadium,
nickel and cadmium on the environment and on health has been reviewed by
Berry and Wallace (1974), Braunstein et al. (1976), the National Research
Council (1974, 1975) , and the International Agency for Research on Cancer
(1976). The formation, degradation, and bioaccumulation of PAH and their
potential environmental impact have been reviewed by Braunstein et al.
(1976), Andelman and Suess (1970), Andelman and Snodgrass (1974), Borneff
(1975) , National Research Council (1972), ZoBell (1971) and Radding e_t al.
(1976). The limited information available on heterocyclic compounds has
been reviewed by the International Agency for Research on Cancer (1973).
-------
- 75 -
III. ENVIRONMENTAL EXPOSURE FACTORS: COAL TAR PITCH
A. Production and Consumption
1. Quantity produced
All of the coal tar commercially available in the United States
is the residue of by-product coke oven tar distillation. Coke plants are
classified as furnace plants (owned by iron and steel companies to produce
blast furnace coke for their own use) and merchant plants (associated with
chemical companies or gas utilities producing blast furnace or foundry
coke for sale on the open market). In 1974, the 48 furnace plants accounted
for 92 percent of the coke oven production and the 14 merchant plants for
8 percent (U.S. Bureau of Mines, 1975) (Table III-l).
2. Market trends
The absolute quantity of pitch available to process depends on the
amount of coal tar produced, which, in turn, depends on the type and amount
of coal carbonized for metallurgical coke production (Figures III<-lr2) .
However, the amount of tar produced will always be roughly proportional
to the metallurgical coke requirement (Mutschler, 1975). In 1974, all
coke ovens produced tar varying between 6 and 9 gallons per ton of coal
carbonized. Plants in West Virginia, Colorado, California and Utah used
large percentages of high-volatile coals, and thus had higher yields of
tar per amount of coal coked (U.S. Bureau of Mines, 1975).
Generally the amount of tar available for processing is limited
first by the need for tar-pitch liquid fuels in steel-melting and blast
furnaces (McGannon, 1971). In 1974, for example, coke plant operators
-------
- 76 -
TABLE III-l
CRUDE TAR PRODUCTION AND PROCESSING:
PITCH PRODUCTION 1954-1975
Year Tar produced Tar processed Pitch* produced
million gallons million gallons thousand tons
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
716
853
833
873
669
654
688
633
650
672
763
803
802
780
761
769
761
679
747
732
677
646
556
679
734
674
555
534
616
604
610
573
602
616
605
595
644
667
658
572
593
554
503
450
1638
2062
2068
1907
1590
1528
1905
2045
1879
1788
1877
2004
1935
1875
1933
1870
1758
1312
1368
1386
1240
1227
* Includes soft, medium and hard pitch, pitch of tar coke and pitch emulsion.
Does not necessarily include road tar or other special tar categories.
Source: U.S. International Trade Commission, 1954-1976
-------
- 77 -
FIGURE III-l.
CRUDE COAL TAR PRODUCED AND PROCESSED
IN BY-PRODUCT COKE OVENS
850
C/J
<750
I650
5
550
150'
350
N'
• TOTAL PRODUCTION
• A QUANTITY PROCESSED
•-•,
\
/ X ,.
/A / V-.
-AU/ A/--
'\ / A W \
A/: ^ A' \
•vy V \A/
A
\
\
1955 1960 1965 1970 1975
YEARS
Source: U.S. International Trade Commission, 1954-1976
-------
- 78 -
FIGURE III-2. ANNUAL PITCH PRODUCTION AND SALES 1954-1975
2100
1900
CO
p
1700
CO
:1500
1300
bllOO
900-
700
• PRODUCTION
A SALES
i i « « i • * i i
1955 1960 1965 1970 1975
YEARS
Source; U.S. International Trade Commission, 1954-1976
-------
- 79 -
consumed 55 percent of the coal tar produced; 50 percent of this was processed
by the operators and 49 percent consumed directly as fuel. Thus, in 1974,
27 percent of the total tar from coking operations was consumed directly as
fuel. In the past ten years, this percentage has generally varied between
12 and 27 percent (U.S. International Trade Commission, 1966 - 1976).
Until recently, the coal tar pitch market was dominated by the use of
pitch as a fuel. The importance of pitch as a binder in carbon and graphite
products has increased, however, with the largest single use of pitch being
as a binder in carbon electrodes used in the manufacture of aluminum (Table
III-2).
In the past three years, demand for metallurgical coke has averaged
approximately 85 million tons annually (Coal Age, 1976). By 1985, assuming
no major changes in iron reduction technology, annual metallurgical coke
demand should reach 109.4 million tons (Mutschler, 1975).
Formcoke briquetting (no description found in the literature) has been
proposed as an alternative to coke oven production of metallurgical coke.
Currently, a formcoke pilot plant is being tested at Sparrow Point, Maryland,
by a consortium of four steel companies and one coal company. At Inland
Steel's Indiana Harbor Works, East Chicago, Indiana blast furnace operation
and iron quality were normal in test runs using up to 50 percent formcoke.
(U.S. Bureau of Mines, 1975). If formcoking is successfully implemented by
1985, demand for metallurgical coke could be as low as 67 million tons
annually (Mutschler, 1975).
Potential sources of pitch are coal liquefaction and gasification, of
which a number of bench scale models and pilot plants are now being tested.
Each different process has different effluent problems: for example, the
Hygas process yields negligible quantities of tar, but high concentrations
-------
- 80 -
TABLE III-2. CONSUMPTION OF COAL TAR PITCH BY MARKET (THOUSAND TONS)
Use
Fuel
Binder for carbon
products
Roofing
Fiber pipe
Coatings
Misc. (total)
Refractory pitch
Target pitch
Foundry sands
Average
1950-52
822
200
280
65
130
130
na
10
na
1960
925
220
na
95
90
150
. na
10
na
1964
912
490
130
95
90
160
na
10
25
1977*
200
720
80
na
na
150
6
10
na -
na = not available
*Projected figures
Source: Cohrssen, 1977
-------
- 81 -
of phenol. On the other hand, the Synthane process yields negligible phenol
concentrations, but large amounts of tar. The quantity of a "by-product" such
as phenol, oil or tar within one system can vary as much as 100-fold depend-
ing on process variables (Massey, 1977).
3. Market prices
From 1969 until 1973, the price of crude coal tar increased from
$0.10 per gallon to $0.12 per gallon. In 1974 and 1975, coal tar was worth
an average of $0.33 per gallon (U.S. International Trade Commission, 1976).
From 1964 to 1974, the value of pitch increased from $39 per ton to $95 per
ton (Table III-3). The current average price for soft, medium and hard
pitch exceeds $102 per ton and is expected to continue increasing (U.S.
International Trade Commission, 1954-1977).
4. Producers and distributors
In 1975, five of sixty-two coke oven plants listed pitch as a by-
product in information given to the U.S. Bureau of Mines, Division of Fuels
(1976b). These plants are:
U.S. Steel Corp., Fairfield, Alabama
Gary, Indiana
Clairton, Pennsylvania
Bethlehem Steel Corp., Johnstown, Pennsylvania
Wheeling-Pittsburgh Steel Corp., East Steubenville,
West Virginia
This information implies, perhaps not accurately, that all other pitch
was derived from tar distillation, rather than by-product coking, at facilities
other than coke ovens.
The following companies may be considered producers and/or distributors of
coal tar pitch (Oil, Paint and Drug Chemical Buyers Guide 1975-76; U.S. Inter-
^
national Trade Commission, 1976) :
-------
- 82 -
TABLE III-3. PITCH SALES AND VALUE
Year
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
Sales
(thousand tons)
1119
1081
1167
1128
1219
1311
1292
1033
1009
1001
882
888
Value
(dollars)
43,700
38,400
43,100
40,900
40,900
41,500
46,400
48,200
48,600
50,800
83,600
90,300
Unit Value1
(dollars/ton)
39
36
37
36
34
32
36
47
48
51
95
102
This value represents an average of unit values for soft, medium and hard
pitch.
Source: U^S. International Trade Commission, 1964-1976
-------
- 83 -
Allied Asphalt and Mineral Corp.
Allied Chemical Corp., Semet-Solvay Div.
Coopers Creek Chemical Corp.
Crowley Tar Products, Inc.
Donner-Hanna Coke Corp.
Bethlehem Steel Corp., Interlake, Inc.)
Husky Industries
Jennison-Wright Corp.
Koppers Co., Inc. Organic Materials Div.
Ore and Ferro Corp.
Reilly Tar and Chemical Corp.
Samuel Cabot, Inc.
USS Chemicals, Div. of US Steel Corp.
Witco Chemical Corp., Pioneer Div.
Ziegler Chemical and Mineral Corp.
5. Production process
Pitch is the residue from fractional distillation of the tar that volatil-
izes during the destructive distillation of coal. There are 62 coke oven bat-
teries operating in the United States, two-thirds of which are more than twenty
years old. Ninety-two percent of the coke produced is used as a reducing
agent in blast furnaces; eight percent is used as foundry coke (U.S. Depart-
ment of Labor, 1975).
Information in the following section on the basic method of pitch
production was derived from McNeil (1966a,b; 1969), U.S. Department of Labor
(1975), and Lauer (1974).
Coal is coked at high temperatures (above 1100°C) in the absence of air
for an average of 18 hours. Softening of the coal begins above 350°C; fluidity
increases as the temperature increases. Between 400° and 500°C, most of the
volatile tar and gases, which represent 20 to 35 weight-percent of the initial
coal charged, are evolved, then collected for by-product recovery. Above
550°C the residue solidifies, although some gas is still evolved. By 900°C,
the solid residue is coked; continuing the process at higher temperatures
results in a coke of greater purity.
-------
- 84 -
The tarry volatiles and gases are removed through refractory-lined
standpipes to a collecting main where their temperature is reduced from
600° or 700°C to 100°C by spraying with a dilute ammonia liquor. The
gases, tar and liquor are then separated.
Primary distillation of tar involves "topping" (stripping off fractions
boiling below 300°C), leaving a refined (base) tar residue. There is no
strict delineation between the base tar and soft pitch, although the base
tar is usually defined as having a softening point of less than 50°C.
Soft pitch has a softening point (ring and ball) of 50° to 75°C, medium
pitch a: softening point of 75° to 85°C, and hard pitch a softening point of
85d to 120°C. Although pitch can be cut back with lower boiling coal tar
fractions to yield softer grades, it is ordinarily the extent of distillation
that determines the pitch hardness. Topped tar and soft pitch include
quantities of the creosote fraction, which may contain 12 to 14 percent
phenanthrene and 2 to 4 percent acenaphthene, fluorene, diphenylene oxide,
anthracene and carbazole, as well as naphthalene and phenolic compounds.
Although there are many variations in process design for tar distillation,
most are highly automated processes. The essential features include a re-
fractory brick lined tube-still furnace through which the tar flows, flash
chambers in which water and volatiles are separated from the crude tar,
and one or many bubble-cap fractionating columns in which tar vapors are
separated by boiling range. Most tar distilleries use multiple flash chambers
to separate out the pitch before fractionating the tar. Because tars are
thermally unstable, overheating, the most dire consequence of which is coke
formation in the apparatus, is avoided during distillation.
-------
- 85 -
B. Uses
1. Major uses
Information in the following two sections was derived from Liggett (1964),
Lauer (1974), Shuler and Bierbaum (1974), and Encyclopaedia Britannica (1969).
Aside from consumption as a fuel in open-hearth furnaces, the major
usage of pitch is as a binder and an impregnant in baked and graphitized carbon
products. Pitch, because of its high specific gravity, high carbon content and
plasticity at the temperatures used in graphite manufacture, is utilized as
a binder for petroleum coke (derived from delayed coking of heavy residual oils
or asphalt) or for carbon black, natural graphite, gilsonite coke and anthra-
cite coal. In the production of commercial carbon products the pitch binder and
petroleum coke (or other) filler are subjected to temperatures of 950° to
1100°C; the production of graphite requires temperatures up to 3000°C. Fol-
lowing baking and impregnation with hot pitch, the pitch-coke mixture may be
used directly (e.g. carbon anodes in aluminum production), or graphitized be-
fore use (e.g. specialty products, resistors in electrolytic furnaces and
foundry mold facings).
Of the pitch used in baked and graphitized products, the greatest
quantity is consumed in various electrode applications. Direct-heating
electrolytic furnaces for aluminum, lithium, potassium, sodium, calcium and
magnesium production commonly use prebaked carbon anodes. In the case of
aluminum production, 540 pounds of baked carbon anode delivers approximately
130,000 amperes of direct current to a submerged bath of alumina, molten cryo-
lite and aluminum fluoride. The aluminum collects at the "cathode" formed
by the carbon refractory lined pot bottom, while oxygen collects at the anodes
which are consumed during the process. About 50 pounds of carbon anode are
required for 100 pounds of aluminum produced. . _
-------
- 86 -
Carbon electrodes are also used in the following processes: electric arc
furnace melting and refining of ferrous metals; submerged arc electric
furnace production of phosphorus, ferroalloys, and calcium carbide; and
diaphragm-type and mercury-cathode-type caustic chlorine cells.
Although prebaked carbon electrodes are most commonly employed, the
applications of the Soderberg (self-burning) electrode are increasing. This
electrode is extruded as a soft paste of calcined filler (petroleum coke) and
pitch binder (25 to 35 weight-percent) into an electrolytic bath; the electrode
is coked at 950°C, consumed and continuously replaced during the process of
use.
Uses of pitch that depend primarily on its heat resistance qualities
are taking over an increasing portion of the baked carbon market. Carbon
refractories are a relatively recent development in the metal and glass industries.
The addition of pitch to a firebrick formula results in brick that can
withstand the physical and chemical stresses encountered as part of a furnace
lining that must tolerate temperatures up to 2000°C as well as the corro-
sive action of molten metal or glass slag.
Pitch-bonded bricks are usually composed of sintered magnesite or dolo-
mite and coal tar pitch, the pitch inhibiting hydration of the minerals. The
mixture of sintered mineral filler and binder is pressed into shape at 130°C.
The pitch is coked as the bricks are fired. Pitch is also used to impregnate
super-duty fire clay and alumina brick. The heated bricks are pressure im-
pregnated at. 200°C and contain six precent by volume pitch when finished. The
bricks are not fired to carbonize the pitch.
Refractory bricks may be used in the basic oxygen steel furnace, blast
furnace, pots used in aluminum and alkali metal manufacture, electric re-
duction furnaces in ferroalloy manufacture, and in foundry cupolas.
-------
- 87 -
Specialty carbon products requiring the use of graphite include
dies for high-temperature metal molding, graphite seals, bushings, carbon
brushes, pencil "lead", woven graphite felt for high temperature insula-
tion, arc welding materials, foundry castings for highly reactive metals
(titanium, molybdenum, zirconium), and nuclear reactor moderators.
Carbon anodes used in aluminum production are often manufactured
by the primary aluminum producer. Other manufacturers of carbon and gra-
phite products include Airco-Speer Carbon-Graphite, Carborundum Co.,
Great Lakes Carbon, Collier Carbon and Chemical, and Union Carbide.
2. Minor Uses
In 1969, 55 million gallons of tar, including pitch and tar used
by homeowners for blacktopping driveways, were used in the United States
for. road building (Lauer, 1974).
Roofs covered with pitch are almost entirely confined to large,
low slope commercial warehouses, factories or large buildings. Roofing
uses, including "tar" saturated felts, pitch cements and cutbacks, were
expected to require the use of 80 thousand tons of pitch (softening points
of 50° to 60°C) in 1977 (Table III-2).
About 10 thousand tons are used annually to manufacture clay pigeons
used in trapshooting. "Target pitch" has a softening point of 125°C or
higher and is mixed with pulverized minerals like limestone, then molded
into the traditional saucer-shaped target. The pitch imparts brittleness
which enhances the shattering (Lauer, 1974).
The use of pitch in waterproof coatings has declined, largely because
of competition from asphalt and synthetic materials. Some specification
coatings are produced, but information and estimates about them are un-
available (Lauer, 1974).
-------
- 88 -
Coal tar has been widely used in a variety of topical medications such
as dandruff and fungicidal shampoos, acne remedies and ointments for psoriasis
and eczema.
C. Environmental Contamination Potential
1. Emissions from production
a. Coke ovens and tar distilleries
A number of studies have been directed at determining the magnitude of
hazard that coke ovens present, both to the worker and to the general public.
Levels of PAH in airborne emissions at one such steel and coke operation are
presented in Table III-4. Almost no work, however, has been done to determine
whether tar distillation facilities, either part of a by-product recovery
system or independently operated, contribute polynuclear aromatic hydrocarbons
or metals to the environment.
Masek (1972) collected suspended dust and air samples in three Czechoslovakian
coal tar distilleries, particularly focussing on areas where the tar and pitch
were pumped and storage vessels emptied and filled. Benzo(a)pyrene levels in
the dust ranged from 121 to 2544 /ig/g, primarily associated with dust of
less than five micrometers diameter. Levels of BaP in the air ranged from
0.30 to 8.49jig/m3. Most PAH emissions in modern tar distilleries are a
result of leakage around seals (Masek, 1972; von Lehmden ejb al_i, 1965).
b. Graphite manufacture
The production of any baked or graphitic carbon product begins with
certain basic steps: calcined filler is pulverized, cleaned and sized, then
mixed at 140 to 175°C with pulverized or heated liquid pitch, which constitutes
15 to 30 weight-percent. Once the petroleum coke (filler) and pitch mixture
has been molded or extruded (at about 100°C and 400 to 8000 psi) it is baked,
perhaps as long as four weeks, in a gas-fired furnace at 950° to 1100°C, then
-------
- 89 -
TABLE III-4. LEVELS OP AIRBORNE PAH IN EMISSIONS ASSOCIATED WITH AN
INTEGRATED STEEL AND COKE OPERATION
Concentration (yg/g
PAH suspended particle)
Benzo(a)pyrene 89
Benzo(e)pyrene 43
Benzo(ghi)perylene 77
Coronene 4.1
Anthracene 29
Fluoranthene 33
Pyrene 75
Perylene 10
Source: von Lehmden et al., 1965
-------
- 90 -
slowly cooled. At the end of the baking period, 10 to 15 percent of the green
(uncoked) body weight will have been lost; 30 to 40 percent of the binder will
have volatilized, as emissions which may or may not be adequately controlled,
and the remainder coked. After cooling, the baked carbon may be impregnated
with hot pitch and subjected to temperatures up to 3000°C. It is important
to note that the pitch component is not present in the final graphitic
product (Oil, Chemical, and Atomic Workers International Union, 1977).
Large amounts of dust are produced during the grinding, mixing and
handling of the petroleum coke and the pitch. Coal tar pitch volatiles
may be present during baking and impregnation. Pitch may contain vanadium,
iron, boron, lead, and other metals, which are a potential hazard.
No work has been found that examines emissions from carbon baking
and graphitizing; however, a study by Griest et al. (1977) examines fugitive
emissions associated with a bench scale graphite production operation.
The grinding of pitch-coated coke resulted in high BaP concentrations,
0.23 to 0.63 mg/m3 air. In measurements taken to determine ambient levels
of BaP not associated with any particular operation, the BaP concentration
reached a peak of 0.72 mg/m3. The study does not necessarily reflect working
conditions or the type and quantity of emissions escaping to the atmosphere.
Electrodes used by primary aluminum producers are often manufactured
in-house. Several suggestions for minimizing air pollution from carbon anode
manufacture include the use of air pollution abatement equipment - scrubbers,
multicyclones, baghouses and fume incinerators - and the use of carbon anodes
prebaked at 1100°C rather than self-burning (Soderberg) electrodes to elimin-
ate most of the volatiles in the pot room (Donaldson ejt alU , 1972; Larsen,
1973; Shuler, 1973}.
-------
- 91 -
c. Other production processes
Pitch can be modified in much the same ways as asphalt. Air blowing
pitch at 220° to 360°C will increase the binder resin content. Subjecting
pitch to pressures from 50 to 500 psi at 370° to 488° C for several hours
produces a harder pitch. (Hoiberg, 1966). No information on the practices
of air blowing or thermal treating was found for pitch.
Bolotova et al. (1967) measured BaP emissions in and near a plant making
pitch-saturated roofing materials. The pitch was maintained at 120°C. The
BaP level in the plant was 0.001203 mg/m3; at a distance of 100 meters from
the plant it was 0.000129 mg/m3 ; at 500 meters it was 0.000047 mg/m3.
Sawicki (1967) reported the BaP level near a sidewalk tarring operation
as 0.078 mg/m3.
Samples of fresh fumes obtained under experimental conditons from coal
tar pitch maintained at 200°C consisted largely of phenanthrene and anthra-
cene (Table III-5) (Kittle and Stukel, 1976). Low fume or no-burn pitch
(Koppers Co.) is available for roofing operations and its use should be en-
couraged (Hervin and Emmett, 1976b; Kittle and Stukel, 1976).
Air polluted by coal tar pitch fumes is characterized by high pyrene/BaP,
BeP/benzo(ghi)perylene, and BaP/coronene ratios (Sawicki e_t aJL., 1962).
Heterocyclic compounds such as acridine, carbazole and their derivatives
may also be present in pitch fumes (White, 1975; Sawicki e_t al_., 1965).
2. Contamination potential from storage,_' transport and disposal
Because pitch is often used in liquid form, it is economical to store
and ship it at elevated temperatures as a liquid (Smith et al., 1966).
Solid pitch is handled as flakes or rods (McNeil, 1969). No information on
contamination from pitch storage or transport was found.
-------
- 92 -
TABLE III-5. COMPOSITION OF FRESH FUMES FROM ROOFING PITCH
PAH identified Weight Percent
Phenanthrene/anthracene 36.4
Fluoranthene 11.8
Carbazole 9.6
Fluorene 9.1
Pyrene 8.5
Naphthalene, its methylated
derivatives, and xanthene 24.6
Source: Kittle and Stukel, .1976
-------
- 93 -
No information on disposal of pitch was encountered; it is unlikely that
significant quantities are simply thrown away since pitch can be used as a
fuel.
3. Contamination potential from use
Pitch and tar-pitch mixtures are important fuels for the open hearth
furnace (McGannon, 1971). The background levels of coal tar pitch volatiles
in steel and coke operations make it difficult to ascribe blame to any single
substance or operation. No study addressing itself to pollution by pitch
as a fuel was found.
The largest market for pitch is as an electrode binder and impregnant,
yet little attention has been paid to this potential source of carcinogenic
polycyclic and heterocyclic compounds or metals. In theory, graphite electrodes
lose the volatile components during baking and graphitization and are no
longer a source of PAH during use. In contrast, carbon electrodes not only
lose volatiles throughout the entire baking process (Gromiec, 1975), but
they may also be a source of PAH during use. Soderberg (self-burning)
electrodes are a significant source of pitch volatiles (Shuler and Bierbaum,
1974; Larsen, 1973; Konstantinov and Kuzminyuk, 1971).
Electric arc furnaces may be lined with carbon refractories; carbon
electrodes may be used in them as well. Tanimura (1968) measured BaP levels
of 0.286 mg/g suspended particulate near an electric steel furnace; no source
of the BaP was suggested.
The contribution of pitch to foundry pollution is not documented. A re-
view by Bates and Scheel (1974) indicates that much work on foundry pollu-
tion, whether or not caused by pitch, needs to be done.
-------
- 94 -
Clay pigeons haye been Implicated as the source of pitch which has
caused poisoning in livestock up to 35 years after an area was used for
trapshooting (Kernkamp, 1964). Usually poisonings occur one or two years
after the initial deposition of target pitch.
In addition to being a source of PAH, pitch may be a source of metals.
Little work has actually been done on the trace metal content of pitch
and its volatiles except as metals affect engineering performance. Levels of
trace metals in pitch volatiles at a coke oven battery were determined by
Schulte et al. C1975J. Zinc constituted over half the metal concentration;
copper and manganese were of intermediate concentration; traces of nickel and
chromium wese found. Also present in pitch are vanadium, iron, and boron
(Liggett, 1964).
4. Weathering
There has been much less work done on the weathering of pitch than of
asphalt, probably becauses the uses in which pitch is exposed to the environ-
ment are in its smaller markets: paving, roofing and coatings. The most
significant factors in pitch weathering are evaporation of the more volatile
tar fractions and oxidation. Pitch is highly water resistant and shows little
response to ultraviolet light (Phelan and Rhodes, 1966).
Asphalt and occasionally coal tar pitch are used as soil stabilizers.
A study by Perov (1969) on the migration of heavy coal tar fractions suggests
that the use of pitch should be avoided for soil applications. Pitch can
contain anthracene oil, phenolic and cresolic compounds. The anthracene
fraction migrates slowly and tends to be retained at shallow depths for
prolonged periods. The phenolic and cresolic compounds pass through the soil
column quickly and accumulate in deeper layers. Decomposition of these
heavy coal tar fractions, which are present in appreciable concentration in
-------
- 95 -
pitch used for road work and bank stabilization, proceeds slowly. Perov
(1969) concludes that elution of water-soluble compounds from heavy coal
tar fractions is a potential threat to groundwater supplies.
As a result of weathering and biological degradation, pitch may re-
lease metals, organometallic complexes, polycyclic and heterocyclic hydro-
carbons to the soil, air or water. The reviews on metals and PAH mentioned
in Section II. C.5. (asphalt) can be useful in evaluating the potential
hazard of pitch in the environment. Considering the variety and potential
carcinogenicity of compounds which may be made available from weathered
pitch or from pitch fumes, much work needs to be done on the subject of
bitumen degradation.
-------
- 96 -
IV. ANALYTICAL METHODS
A number of analytical techniques in various combinations have been
developed for the identification and determination of some of the components
of complex bituminous mixtures such as asphalt and pitch.
Complex mixtures derived from fossil fuels, such as coal tar pitch and
asphalt, contain many chemicals of biological significance. There has been
a great need to identify these compounds, especially the polynuclear aro-
matic hydrocarbons (PAH) and aliphatics. Among these are carcinogens,
cocarcinogens and inhibitors. Such components may be distributed through-
out products derived from these complex mixtures or may be disseminated
into air, water and soil.
A. Sampling
High volume air samplers are used to collect atmospheric samples by
drawing air through filters at varying velocities. Glass fiber filters
without binders, which are relatively inexpensive, remove nearly all par-
ticles greater than 0.3 microns (Hoffman and Wynder, 1968; Kukreja and
Bove, 1976). Richards e_t al. (1967) compared glass fiber filters, cellu-
lose acetate membranes, cellulose filters, and cellulose thimbles with
silver membrane filters. The study included determination of weight stability
due to humidity changes and extraction procedures. The conclusion was that
silver membrane filters were most suitable for use in the evaluation of
atmospheric concentrations of coal tar pitch volatiles. Silver membrane
filters, also used in personal air samplers (Seim e_t a^L. , 1974; Richards
_e_t _al_. / 1967; Masek, 1970) have a pore size of about 0.8 microns and show very
little weight loss after benzene extraction, but tend to load up rapidly
with a resultant decrease in flow. When compared to glass fiber filters,
silver membrane filters have a high tare weight and are relatively expensive.
-------
- 97 -
Millipore filters have been used for collecting metals in coke oven emissions
(White, 1975). Several types of combination filters have been used in per-
sonal samplers (U.S. National Institute for Occupational Safety and Health,
1977a,b). Since low molecular weight PAH pass through various combinations
of silver and glass filters (Schulte et_ al., 1974, 1975; Seim e_t al_. , 1974,
1975a,b), cellulose backup pads have been used with glass fiber filters
without organic binders followed by a silver membrane filter. Use and analy-
sis of such a backup pad has been advised in order to detect all material
passing through the filters. However, in some instances a trap consisting
of charcoal or resin material is also necessary to absorb the more volatile
PAH passing through the mechanical filters (Jones, 1977). When sampling for
particulate matter, asphalt fumes and coal tar pitch volatiles are con-
sidered PPOM (particulate polycyclic organic matter), for which a glass
fiber filter without a silver membrane backup is presently considered to
be adequate CU.S. National Institute for Occupational Safety and Health,
1977a,b).
More than fifty different types of instruments have been used to sample
particulates (Roach, 1973). The mass concentration or the number concentration
of particles in a volume of gas can be determined with the use of appropriate
samplers. Instruments used to measure mass concentration of a particulate
can be equipped with preselectors, such as elutriators or cyclones,to separate
coarse nonrespirable particulates before collection. Due to the adhesive
property of asphalt fumes a preselector can induce error by trapping
respirable particulates, while collection without a preselector can induce
error by including in the calculated mass of asphalt fumes the amount of
total particulate in the nonrespirable size range (U.S. National Institute
for Occupational Safety and Health, 1977a). . _
-------
- 98 -
Sizing of particles has been performed on emissions. Five- and
seven-stage high volume samplers using combinations of glass slides and
glass fiber filters have been used to determine the amount of respirable
particles (Kertesz-Saringer e_t al., 1971; Natusch and Wallace, 1974; Kittle and
Stukel, 1976). White (1975) has sized particles on low volume samplers
using aluminum foil.
Other sampling devices have been used less frequently: a high volume
sampler collecting particulate on paper filters (Tanimura/ 1968), an • elec-
trostatic precipitator to collect samples of tar vapors (Bonnet, 1962; Hoffman
and Wynder, 1968), a greased-plate technique to sample particulate concentrations
in a quench tower during quenching of hot coke (Fullerton, 1967)/ cascade im-
pactor and thermal precipitation to collect samples in a retort house (Lawther
et _aJL, 1965)/ and bubbling air through solvents to collect samples at a coke
plant (Bondarava, 1963).
There are major problems with the sampling methods and filters. Materials
to be sampled may be incompletely collected on the filters, as indicated by
their presence on backup pads or charcoal tubes. In addition to differences
in sampling efficiency for various compound types, the entire range of res-
spirable particulates (submicron to 10 microns) may not be collected on the
filters used. Heat, increased air velocity, sunlight, and ultraviolet have
been found to decompose or volatilize some PAH, resulting in yields as low
as one tenth of the actual value (Commins and Lawther, 1958; Rondia, 1965;
Thomas et al., 1968; Katz and Monkman, 1964). Collection of the samples at
normal environmental temperatures (20°C) and storage of the samples in a cool,
dark location would minimize the volatilization of PAH (Rondia, 1965) and
the decomposition of even the most unstable PAH (Hoffman and Wynder, 1968).
-------
- 99 -
B. Methods of Sample Analysis
Some preliminary separations of asphalt, coal tar pitch, asphalt fumes,
or coal tar pitch volatiles into their components are necessary prior to the
use of chromatographic separations. These initial separations usually in-
volve solvent extractions and/or precipitations, fractional distillations
and gravity fed adsorption chromatography. Additional adsorption chromatog-
raphy, as described in Section B.l.d., can then be used to separate the com-
ponents further into fractions that can be analyzed by sophisticated detec-
tion methods. The chromatography can be used in conjunction with or prior
to the use of analytical tools for quantitation, as described in Section B.2.
1. Separation Schemes
a. Solvent Extraction and/or Precipitation
A number of extractions (liquid-liquid or solid-liquid) and precipita-
tions are used (.as described in Chapter I) in fractionating asphalt and coal
tar pitch into more manageable components containing PAH and metals.
Similar extraction methods are used for tar, petroleum and crude air samples.
Some of these methods have been developed for concentrating and isolating
metals and organic compounds found in crude air samples (Hoffmann and Wynder,
1968; Hueper ert al. , 1962), cigarette smoke condensate, (Swain et al. ,
1969; Severson e_t al. , 1976; Snook et al_. , 1975; Finelli et al_. , 1972),
white petroleum products (Popl e£ al_*, 1975), carbon black (Gold, 1975),
heavy end distillates (Altgelt and Gouw, 1975) , carbon paste plants
(Bjjrfrseth and Lunde, 1977), marine organisms (Warner, 1976) , and coal
tar and coal tar pitch (White, 1975).
In the coal tar and coal tar pitch method of White (1975), based on
the procedure of Swain et al., (1969), about 100 grams of coal tar is dis-
solved in 500 ml of ether. The coal tar solution is extracted with ten
-------
- 100 -
percent aqueous sodium hydroxide to remove the tar acids, ten percent
hydrochloric acid to extract the tar bases, and ten percent sulfuric acid
to extract the aliphatic olefins. The remaining solution, combined with
ether washings of these aqueous extracts, constitutes the neutral fraction
of coal tar. The raw coal tar sample is thus separated into particulate
matter (20%), neutral (60%), basic (3%), acidic (weak and strong) (3%),
and water soluble (14%) fractions.
b. Solid-Liquid Extraction
Most particulate air samples (asphalt fumes or coal tar pitch volatiles)
collected on filters use some type of Soxhlet (solid-liquid) extraction
(Karasek et al., 1978). Soxhlet extraction glassware has been widely used
for solid-liquid extraction since the samples can be washed with clean
redistilled solvent and the extract collected and concentrated at the same
time.
Soxhlet extractions with acetone have been used for more than 20 years
in England to extract PAH (Waller, 1952). Benzene is a very good but po-
tentially hazardous solvent which completely extracts PAH from particulates with
diameters greater than 80 microns (Hoffman and Wynder, 1968). The extrac-
tions, are carried out at temperatures below 80°C to prevent decomposition of
BaP. A variety of other solvents such as pentane, cyclohexane, diethyl ether,
methylene chloride, and ether:toluene:cyclohexane (1:2:1) have been tried
with reasonably good recovery. The polar PAH, however, are not extracted
quantitatively (Stanley e£ al., 1967; White, 1975).
With benzene, a large amount of background material is also extracted,
complicating further analyses which involve isolation, identification and
quantitation of compounds present in low concentrations. Cyclohexane is con-
sidered preferable to benzene since it will remove most of the PAH with less
background material (Lijinsky et al., 1963).
-------
- 101 -
The PAH extracted are subject to decomposition by UV radiation, and
therefore the work is carried out under yellow light (Tanimura, 1968).
Total particulates are measured as the difference in weight of the filter
before and after sampling, following conditioning in a desiccator. The
benzene solubles can be determined by weighing (1) the residue after evap-
oration to dryness of 5 ml of the extract, or (2) the filter before and after
extraction. The weight is then related to the volume of air passing through
the filter averaged over the time of collection;
A number of objections, however, have been raised by investigators con-
cerning Soxhlet extractions. (Seim et^ al., 1974, 1975b; Schulte et al.,
1974, 1975; Golden and Sawicki, 1973). The extractions have been found to
be unreliable and not reproducible. The extraction procedures are time con-
suming, decompose some of the pollutants, lack precision, do not collect all
of the PAH, lose some of the volatiles, lose particulates during handling
and extraction and do not correlate well with PAH content. Filter disintegra-
tion and change in water content between weighings cause further problems.
New gravimetric methods are being developed which involve ultrasonic ex-
traction of the filter with benzene, carbon disulfide, or cyclohexane. After
sonication for five to ten minutes, an aliquot of the extract is evaporated in
a teflon weighing cup and weighed on an electro balance (Seim, 1975b; Golden
and Sawicki, 1973). Modifications of these methods are being developed by
various government agencies, such as the U.S. National Institute for Occupa-
tional Safety and Health (1977) and the Occupational Safety and Health Admin-
istration. Such methods avoid problems generated by the Soxhlet extractions.
Trace metal samples are collected on high volume glass fiber filters.
The filters are wet ashed with ultra pure acids and the resulting ash is
taken up in solution. The sample is then analyzed_by analytical tools for
various metals (Schulte et al., 1974, 1975; Fassel and Kniseley, 1974).
-------
- 102 -
c. Distillation
Fractional distillation has been used for samples with wide boiling
ranges (Sawicki et^ al_., 1964). Phenols, nitrogen bases, PAH, paraffins, and
anthracene in coal tar pitch have been separated by distillation (Charette
and Bischofberger, 1961). Initial separations have also involved vacuum
distillation (Altgelt and Gouw, 1975).
d. Chromatoqraphy
Chromatographic separations mainly concerned with organic compounds are
usually performed after distillation and/or solvent extractions and
precipitations. There are a wide range of chromatographic techniques, such
as gas chromatography (GC), gel permeation, ion exchange, and paper and liquid
adsorption, that have been discussed in detail in numerous reviews concerned
with coal tar, coal tar pitch and coal tar pitch volatiles (Schulte et al.,
1974, 1975: White, 1972, 1975), heavy end distillates (Altgelt and Gouw, 1975),
and asphalt and asphalt fumes (Couper, 1977; Schweyer, 1975; Knotnerus, 1967X
Less commonly used techniques are. also discussed in these reviews.
Adsorption;
Liquid adsorption chromatography techniques include gravity fed column,
thin layer, and high performance liquid or high pressure liquid (HPLC). The
adsorbents that are used include florisil, silica, alumina, charcoal, magnesia
and sephadex LH-20 CAltgelt and Gouw, 19751. Modified adsorbent materials
consisting of high molecular weight polymexs coated or bonded to the surface
of chromatographic supports are now being applied more readily to HPLC work.
Alumina and silica gel are the most commonly us,ed supports in gravity
fed column chromatography. Solvents with necessary polarity from pentane to
ethanol are used in succession or in combination to effect separation of
mixtures into aliphatic, aromatic, and heterocyclic compounds. This type
-------
- 103 -
of chromatography has been applied to the separation of crude air samples
(Hoffman and Wynder, 1968; Hueper et al., 1962), cigarette smoke condensate
(Swain et:
-------
- 104 -
The increasing use of high pressure liquid or high performance liquid
chromatography (HPLC) (Hadden et al., 1971; Brown, 1973; Simpson, 1976) for
separation and determination of PAH has led to (1) reduction in purification
time, (2) optimization of fractional resolution, and (3) reproducibility of
fraction collecting. Due to the availability of highly efficient micropacked
analytical columns (for samples <_ 3 mg) with various adsorbents, programmable
solvent mixtures, and mass spectrometry detection methods, mixtures of aro-
matic compounds have been successfully separated and analyzed for PAH at room
temperature in a matter of hours. The PAH in the samples can be collected
without decomposition, already in solution for further analysis. In some
instnces HPLC has eluted and resolved high molecular weight PAH (five to
seven rings), such as benzo(e)pyrene from benzo(a)pyrene, in less than half
the. time required for the same separation on a packed column by gas chroma-
tography at elevated temperatures (Thomas and Lao, 1977; Jones and Yang, 1975;
DeStefano and Kirkland, 1975; Klimish, 1973a,b; Klimish and Fox, 1976;
Soedigdo et al., 1975; McLafferty et a^., 1975; Wheals et ea., 1975;Goldstein,
1976; Hunt et_ al., 1977; Ives and Giuffrida, 1972). HPLC has been used in
the analysis of heavy end petroleum distillates (Suatoni and Garber, 1976;
Suatoni and Swab, 1975, 1976; Schmit et. al_., 1971; Jewell et al^., 1972a,b;
Hirsch et: al_., 1972; Vogh and Dooley, 1975), asphalt and asphalt fumes
(Couper, 1977; Schweyer, 1975), crude air samples (Dong £t a^., 1976; Fox
and Staley, 1976) and fossil fuels (Thomas and Lao, 1977), and to measure
the solubility of PAH in aqueous systems (May et al_., 1978) .
Gas-Liquid (GC):
GC using packed or capillary columns is a rapid and versatile tool for
analysis of low molecular weight compounds that can be volatilized without
decomposition. It is a widely used separation technique in the analysis of
-------
- 105 -
heavy end petroleum distillates (McKay e_t al_., 1976; Youssef e_t al_., 1976;
Altgelt and Gouw, 1975), asphalt and asphalt fumes (Couper, 1977; Schweyer,
1975; Dorrence and Petersen, 1969; Knotnerus, 1967), petroleum pitch vola-
tiles (Greinke and Lewis, 1975), and air samples (Lao et a^., 1973, 1976),
and for the identification and quantitation of PAH (Duswalt and Mayer,
1970; Popl ejt ea., 1976; DeMaio and Corn, 1966; Dicorcia e_t a^., 1976;
Zoccolillo et^ al^., 1972; Bhatia, 1971). GC has also been used in the
separation and analysis of PAH in coal tar pitch and coal tar pitch vola-
tiles CMaher, 1968; Stroemberg and Widmark, 1970; White, 1975), petroleum,
mineral oil, and coal tar (Lijinsky e_t al_., 1963) and soot samples (Wallcave,
1969), and for the chemical standardization and quality assurance of whole
crude coal tar CGruber et al., 1970).
However, GC has certain limitations, such as requiring a cold finger
for effective trapping of hot gaseous effluent (White, 1975), plumbing that
has to be recalibrated regularly, and loss in the sensitivity of the flame
ionization detector (FID) or electron capture detector (BCD) in order to
provide sufficient effluent to the trap (Thomas and Lao, 1977). Also, FID
or BCD will discriminate only to the extent of the variation in the re-
sponse factor, which is only slight among PAH isomers, and therefore isomers
are not well resolved. Lastly, in order to elute some PAH, a high column
temperature and/or a long retention may be needed which may cause decomposi-
tion and/or a long analysis time.
Dexsil series GC (300 and 400) and capillary columns are among the best
that are used for the analysis of complex mixtures of PAH in environmental
samples (White, 1975). Separations of benzo(e)pyrene (BeP) and perylene
from benzo(a)pyrene (BaP) and benz(a)anthracene from chrysene are poor or
incomplete. Others that have been used are the SE-30, OV-7 and OV-17
-------
- 106 -
columns. Nematic liquid crystals have been developed (Zielinski et al, 1976;
Janini e_t al_., 1975, 1976) to improve PAH separation. The stability, reli-
ability, and resolving ability of these columns are still under investigation.
Gel Permeation;
Gel permeation chromatography is normally performed following solvent
extractions and/or precipitations.
Gel permeation is used to separate asphalt into various fractions in
order to study its composition (Schweyer, 1975; Couper, 1977) and to iso-
late PAH in heavy end petroleum distillates (McKay and Latham, 1973; Cogswell
et al.; 1971; Altgelt and Gouw, 1975; Jewell et al., 1974).
Ion Exchange;
Ion exchange is widely used in analyses of heavy end petroleum distillates
for their acidic and basic components (Altgelt and Gouw, 1975; Jewell et al.,
1972a) and in the separation of metals from tobacco smoke condensate (Finelli
et_ al., 1972) .
Paper;
Paper chromatography has been used to effect separations not accomplished
by column chromatography or in conjunction with column chromatography. How-
ever, standards must be run simultaneously with each sample, the acetylated
paper used is often contaminated and irregular in quality, and recovery is
not quantitative. This technique is not reliable for the separation of com-
plex mixtures (Katz and Monkman, 1964). Paper chromatography has been used
to separate PAH, phenols and bases from coal tar pitch fractions (Masek, 1964;
Macak and Rehak, 1962; Leibnitz et a^., 1958).
2. Identification Methods
The identification and quantitation of PAH found in coal tar pitch, coal
tar pitch volatiles, asphalt, and asphalt fumes are carried out using analy-
tical tools such as infrared, ultraviolet, fluorescence, and phosphorescence
-------
- 107 -
spectroscopy, nuclear magnetic resonance and mass spectrometry, and atomic
absorption spectrophotometry. These tools are used after separation and iso-
lation of PAH and metals from various complex fractions into small concen-
trated samples, using the separation schemes described in Section IV.B.I.
and Chapter I. A number of these methods have been interfaced with various
types of chromatographic techniques to facilitate the characterization of
metals and PAH,
a. Infrared Spectroscopy (IR)
Infrared spectroscopy (Silverstein and Bassler, 1967) has been used to
characterize and identify the functional groups of organic compounds and
chelated metals in coal-derived materials and asphalt samples (Schweyer,
1975; Couper, 1977; Wehry and Mamantov, 1977). Recent developments in
matrix isolation of fourier transform IR spectroscopy (Wehry et al., 1976;
Wehry and Mamantov, 1977) will improve the detection limits and the quanti-
tation methods in the analysis of PAH in mixtures. IR has been used to an-
alyze heavy residual oils (Kawahara, 1969), asphalts (Dorrence and Petersen,
1969), and the following components of coal tar pitch fractions: aromatics
(Rao et a!L., 1960), acids and bases (Karr et^ aa,, 1970), neutral oils (Maher,
1968), paraffins (Maher, 1968), phenols and quinolines (Karr ^t al^., 1958, 1959).
b. Fluorescence and Phosphorescence Spectroscopy
PAH all have characteristic fluorescence and phosphorescence spectra,
lifetime quantum yields and rate constants (Berlman, 1965; Becker, 1969;
Zander, 1968). Fluorescence and phosphorescence techniques (Morgan et al.,
1977; Schwarz and Wasik, 1976; Farooq and Kirkbright, 1976) are 1000-fold
more sensitive than UV spectroscopy, allowing fluorescence excitation spectra
to be recorded at much lower concentrations than the corresponding UV spectra.
In addition, compounds can be selectively monitored in a mixture of two or three
-------
- 108 -
PAH without interference from the other PAH. By selection of optimal
emission or excitation wave lengths, differential techniques can be used
to resolve overlapping PAH spectra. More recent developments using
matrix isolation fluorescence and room temperature phosphorescence will
aid in the analyses of PAH. Matrix isolation techniques using gaseous
solvents will aid in alleviating difficulties of overlap of excitation
and/or emission spectra of different PAH and energy transfer and quench-
ing phenomena (Wehry and Mamantov, 1977) . Phosphorescence of PAH adsorbed
on a variety of surfaces at room temperature would alleviate the use of
frozen matrix and/or degassed samples (Vo-Dinh, 1977).
These optical techniques have been used (1) to detect and characterize
PAH utilizing the Shpol'skii effect at 77°K (Farooq and Kirkbright, 1976),
(2) to determine concentrations of PAH in aqueous systems (Schwarz and Wasik,
1976), and C3) to correlate the carcinogenic potential of PAH with their
fluorescence spectra (Morgan et al., 1977). Fluorescence techniques have
also been used to analyze PAH from air samples (Fox and Staley, 1976; Slavin
et a^., 1977; Lannoye and Greinke, 1974), shale oil (Hurtubise e_t al_. , 1977),
high boiling petroleum distillates (McKay and Latham, 1972), asphalt
CSchweyer, 1975; Couper, 1977), and coal tar and coal tar pitch (White, 1975).
The major drawbacks of fluorescence techniques are the high background
levels, interference from nonflucrescing material, quenching, self adsorption
and photodecomposition. The high background can be due to other fluorescent
compounds in the mixture, dirty glassware, or fluorescent impurities in the
solvent. Therefore solvents must be redistilled or spectroanalyzed for
fluorescent impurities and the cuvettes should be treated with concentrated
nitric or hydrochloric acid. A major improvement in the field of fluorescence
is the marketing of fluorescence units which give corrected spectra that are
independent of lamp output, monochromator grating artifacts, and phototube
-------
- 109 -
response. The spectra generated are independent of instrumentation and can
be compared to spectra of other laboratories. The fluorescence excitation
spectra will be the same as UV spectra at 103 lower concentrations.
c. Mass Spectrometry (MS)
Mass spectrometry (Burlingame e_t al., 1974; McLafferty, 1973; Silverstein
and Bassler, 1967) is utilized in the characterization of PAH at the nano-
gram level after chromatographic techniques and other identification methods
have been used. This method is usually the last technique used in the posi-
tive identification of PAH. Before mass spectrometry can be used, the sample
has to be fairly pure because of the difficulty in determination of isomeric
PAH of similar molecular weight,such as BeP and BaP. The most common
chromatographic technique used in conjunction with MS has been gas chroma-
tography, but with the rapid advances being made in the area of HPLC, this
technique may eventually supplant GC or at least be as widespread (McFadden
et al., 1976; McLaff erty eib a^., 1975; Jones and Yang, 1975; Elbert et al.,
1976). The analysis of mixtures has been facilitated greatly by recent ad-
vances in minicomputers for data reduction and data acquisition and by the
availability of chemical ionization and electron impact sources as one unit
on both the quadrapole and magnetic mass spectrometry instruments.
Mass spectrometry has been used in the analysis of PAH in air pollutants
(Lao et al_. , 1973, 1976), tobacco tar (Lee et aJL., 1976), heavy end petroleum
oils (Jewell e_t al. , 1974; Altgelt and Gouw, 1975) , petroleum pitch volatiles
(Greinke and Lewis, 1975), asphalt and asphalt fumes (Schweyer, 1975; Couper,
1977), coal tar distillates and residues (Shultz et al_., 1967, 1972), coal
derived fuels (Sharkey et al., 1975), and sediment and combustion products
(Hase et al., 1976).
-------
- 110 -
The spark source mass spectrometry technique (Lett et al., 1977) permits
analysis for a large number of metals in a sample. This technique has the
advantage of being able to provide data on the metal content of most samples
down to 0.1 ppm with minimal sample preparation.
d. Nuclear Magnetic Resonance Spectrometry (NMR)
Carbon-13 NMR spectrometry (Silverstein and Bassler, 1967) is being
applied to heavy end petroleum fractions in order to provide evidence for
average structures of molecules present (Jewell et. al., 1974). Proton
coupled carbon-13 NMR provides rapid determinations of series of average
parameters of aromatic hydrocarbons. Proton NMR spectra are not as valuable
as proton coupled carbon-13 NMR spectra when analyzing for PAH in mixtures
(Retcofsky e_t al_. , 1977 L NMR techniques have been used to analyze complex
mixtures, such as gasoline (Myers ejb al^., 1975), asphalt fractions (Keefer
et_ al., 1971; Schweyer, 1975; Couper, 1977), heavy end distillates (Coleman
e_t al^., 1973; Jewell e_t al_,, 1974), and coal tar pitch fractions (Fujiwara and
Wainai, 1961). They have also been used in identification and characteri-
zation of isomeric PAH (Duswalt and Mayer, 1970), PAH (Brooks and Stevens,
1964), paraf f ins (Kochloef 1 e_t al_., 1963) and aromatics in coal tar pitch
fractions (Rao et al., 1960), and as a tracer tool in coal liquefaction
processes (Schweighardt et al., 1976).
e. Ultraviolet Spectroscopy (UV)
UV is used routinely to characterize PAH compounds separated by chroma-
tographic techniques from complex mixtures, basically because many UV spectra
of PAH are available in the literature (Clar, 1964; Friedel and Orchin, 1951;
Orchin and Jaffe, 1962). This technique is highly reproducible and facile.
UV is very specific for individual compounds, so that in some instances
where two PAH are not resolved by chromatography but have different absorp-
tion regions, the contributions of each can be determined, e.g. BeP and
-------
- Ill -
perylene. However, UV spectroscopy is not good in general for analyzing
PAH in mixtures becaufee of the interferences due to each PAH, the high
background, and lower sensitivity than fluorescence. The use of non-ab-
sorbing solvents such as cyclohexane, pentane, methanol and ethanol limits
the solubility of the PAH.
Recent developments in second derivative absorption spectrometry,
however, show promise of being able to analyze a rather complex mixture of
PAH without prior chromatographic separations (Hawthorne and Thorngate, 1977).
This technique, which is still under investigation, will monitor the more
volatile PAH in the vapor phase as well as the less volatile PAH in solvents.
UV spectroscopy has been used to characterize the following materials sep-
arated from "coal tar pitch volatiles" extracts (Sawicki e_t al., 1974;
White, 1975): BaP (Stroemberg and Widmark, 1970), PAH (von Lehmden et al.,
1965; Sawicki et_ al_., 1970a), neutral pentane soluble fractions of asphalt
(Brooks and Stevens, 1964), and quinolines (Vahrmen, 1958). It has also
been used to analyze petroleum pitch volatiles (Greinke and Lewis, 1975)
and asphalt samples (Schweyer, 1975; Couper, 1977).
f. Other Techniques
Atomic Absorption Spectrophotometry (AA) is used in the analysis of metals
from coal tar and coal tar pitch (Schulte e_t al_, 1974; White, 1975) and asphalt
and asphalt fumes (Schweyer, 1975; Couper, 1977). However, computer programs
are needed to make the proper corrections for the interference of other metals
not being analyzed; otherwise, the number of interference standards which must
be prepared becomes unwieldy. More recent developments in the area of induc-
tively coupled plasma-optical emission spectroscopy (Fassel and Kniseley, 1974)
allow true simultaneous multielement analyses on a practical basis (30 metals).
-------
- 112 -
It has been demonstrated that all metals and metalloids can be determined at
the ultratrace level on pi or ug samples. All of the data accumulation on a
simultaneous basis with minimal interelement and data reduction is handled
easily by available computers.
Electron Spin Resonance (ESR) has been used to study organic compounds
and in particular to characterize PAH (Bartle and Smith, 1967) in coal tar and
asphalt (Schweyer, 1975).
X-ray Excited Optical Luminescence is a potential analytical tool (D'Silva
e_t aJU , 1976, 1977) for detecting and quantitating PAH at ultratrace levels
(ppb). This technique is still under development.
3. Discussion of Existing and Proposed Analytical Methods
After the initial separation methods have been completed, a wide variety
of analytical methods which combine chromatographic and spectroscopic tech-
niques have been used in the difficult analyses for a number of PAH from
complex mixtures which may contain over 100 different PAH. The most common
methods which are described in this section have wide application, but have
been most heavily used in the analysis of PAH in coal tar pitch, coal tar
pitch volatiles, and organic material in the urban atmosphere. These same
methods, although not developed for asphalt and asphalt fumes per se, are
readily applied to the analysis of PAH in these mixtures.
Column cnromatography/UV-VIS spectroscopy;
This method, which combines gravity fed chromatography with UV and
visible spectroscopy (VIS), has been used to analyze for PAH in atmos-
pheric particulate matter (Sawicki et al., 1970a) and in air polluted by
coal tar pitch fumes {Sawicki et a^., 1962, 1965). It can also be used to
analyze for PAH from coal tar pitch, asphalt and asphalt fumes. This method,
which has quantitated PAH and their heterocydic analogues in the microgram
-------
- 113 -
range, has been used to analyze for such compounds as anthracene, phenanthrene,
benz(a)anthracene, fluoranthene, pyrene, BaP, BeP, benzo(ghi)perylene, anthan-
threne, coronene, dibenz(a,h)acridine, and dibenz(a,j)acridine (Sawicki et al.,
1964, 1965). However, this method employs a slow chromatographic technique
which requires arbitrary decisions for the cut of each fraction due to vari-
able retention times. A number of days or weeks can be required for the analy-
sis of PAH. Additionally when small quantities are present (below yg range),
or when two or more compounds are not separable and have the same absorption,
UV-VIS will not be useful as a detection technique.
Column chromatography/fluorescence spectroscopy;
The combination of gravity fed solid-liquid chromatography with fluores-
cence spectroscopy has been used to analyze atmospheric particulate matter
for compounds such as those described in the preceding paragraph (Sawicki
et al_., 1970b,c). When applied to the analysis of PAH from coal tar pitch and
asphalt sources, it is an improvement upon the preceding method, since it can
be used to quantitate PAH in the nanogram range (1000-fold more sensitive) and
to analyze for two or three PAH that co-chromatograph. However, this method
suffers from the need for arbitrary decisions for the conclusion of each cut
(fraction) due to variable retention times and from the long time needed for
the chromatographic separations and analyses of PAH. The fluorescence aspect
of the method has to consider instrumentation artifacts such as variations
in lamp output, phototube response, monochromator grating and photodecomposition
of the PAH.
Thin-layer chromatography/fluorescence spectroscopy;
Thin layer chromatography has been combined with fluorescence spectros-
copy to analyze for BaP in bitumens, plants, airborne particulates, various
source effluents including coal tar pitch volatiles (Sawicki erb al^, 1970d,e;
-------
- 114 -
Lannoye and Greinke, 1974; Scharap and Von Wassenhove, 1972; Jackson et al.,
1974b) and atmospheric isomeric PAH (Pierce and Katz, 1975). The analysis for
BaP can be quantitated on a 10 yg to 0.01 yg range depending on the particu-
lar procedure used. However, this method is hampered by the loading factor,
limited efficiency of separation and poor reproducibility. These problems
can be overcome with pure standards and solvents and with TLC plates that are
prepared and activated under the same conditions with known maximum loading
efficiency to prevent streaking of plates.
A more recent modification has utilized adsorption and partition TLC in
a two step process in conjunction with fluorescence spectroscopy to analyze
for 12 isomeric PAH (Pierce and Katz, 1975). It has been possible to sepa-
rate the PAH into 5, 6 and 7 ring compounds (Pierce and Katz, 1975), but
this method further separates isomeric 5 or 6 ring compounds into individ-
ual components. This simple and rapid method has quantitatively resolved
five pentacyclic, two C22 hexacyclic and five C2^ hexacyclic PAH: BeP, BaP,
benzo(b)fluoranthene, benzo (h)fluoranthene, perylene, dibenzo(def,mno)chrysene,
benzo Cghi)perylene, naphtho(1,2,3,4-def)chrysene, benzo(rst)pentaphene,
dibenzo(b,defJchrysene, naphtho(2,l,3-gra)naphthacene and dibenzo(def,p)chrysene.
Gas chromatography/UV spectroscopy:
Gas chromatography (FID or ECD) has been used with UV spectroscopy to ex-
amine coke oven effluents (Sawicki e_t aJU , 1974) for PAH such as f luoranthene,
pyrene, benz(a)anthracene, chrysene, BaP, and BeP. It has also been used to
analyze petroleum pitch volatiles for PAH such as methyl substituted chrysenes,
phenan.threne and pyrenes, pyrene, BaP, BeP, chrysene and benz (a) anthracene
(Greinke and Lewis, 1975) . The detection limit for the PAH by this method is
0.5 to 0.1 yg per compound.
-------
- 115 -
The potential difficulties with this method are the requirements for
trapping of PAH by use of a cold finger, a split in the plumbing, which has
to be recalibrated regularly, a decrease in the detection limits of the FID
or ECD detectors in order to provide sufficient effluent to trap, and pyroly-
sis of PAH at high temperatures (Thomas and Lao, 1977). The FID or ECD
detectors, which discriminate only to the extent of the response factor, vary
only slightly among isomers, and therefore the addition of UV spectroscopy
will aid in the quantitation of two co-chromatographic compounds with differ-
ent absorption wave length maxima, e.g. BeP and perylene. UV spectroscopy
is not useful, however, much below the microgram level.
Gas chromatography/fluorescence-phosphorescence spectroscopy;
This method, which is an improvement upon the GC-UV method, combines gas
chromatography (BCD) and fluorescence spectroscopy. It has been used to analyze
PAH in coal tar, coal tar pitch and coal tar pitch volatiles (White, 1975) and
can be applied to asphalt to quantitate PAH in the ng range (1000-fold more
sensitive than GOuy) and several PAH that co-chromatograph. Some of the
PAH that have been analyzed are pyrene, chrysene, BaP, BeP, benz(a)anthracene,
benzo(h)fluoranthene and perylene. As indicated in the previous paragraph,
the GC aspect of this method suffers from a number of potential problems which
must be taken into account. The instrumentation artifacts due to the fluores-
cence-phosphorescence unit can be corrected by daily calibration of the unit
with standards in degassed emission tubes and then use of degassed samples
for analysis. Both standards and samples need to be trapped by GC to avoid
introducing other variables. With the advent of improved instrument tech-
nology, the corrections for instrumentation artifacts are now incorporated in
the fluorescence units, Photodecomposition of PAH, however, is still a poten-
tial problem. A slightly different method (Burchfield et: al_,, 1971) increases
-------
- 116 -
the sensitivity by use of gas phase fluorescence detection instead of elec-
tron capture detection. Gas phase measurements are more convenient to make
and less susceptible to light scatter by solvents. The fluorescence intensity
is lower but can be increased by using an ellipsoidal condensing mirror
housing. The instrumentation artifacts and photodecomposition still need to
be taken into account. Analyses have been carried out for compounds including
fluorene, anthracene, triphenylene, BaP, dibenz(a,h)anthracene, perylene,
chrysene, pyrene, fluoranthene, and benzo(ghi)perylene.
High pressure liquid chromatography/UV or fluorescence spectroscopy;
A combination of HPLC with UV or fluorescence has been used to analyze
for as many as 17 PAH in atmospheric particulate matter (Fox and Staley, 1976;
Dong et al., 1976) , BaP in coal tar pitch volatiles (Boden, 1976) and PAH
in engine oils (Vaughan et al., 1973). This method has also shown potential
use in the analysis of fossil fuels for PAH (Thomas and Lao, 1977) and has
a very wide potential application in the analysis of all complex mixtures.
In addition to the fact that the potential difficulties of GC do not
apply to HPLC, the HPLC samples are collected at room temperature in non-
fluorescent solvents without decomposition. Larger samples can be introduced
(up to 3 mg) at the column head and the effluent can be stored in the cold
or analyzed immediately by UV or fluorescence detectors. Proper selection of
optimal fluorescence excitation or emission wavelengths or of maximum absorp-
tion wavelengths can permit analysis for two or possibly three PAH that
co-chromatograph. The use of HPLC-fluorescence provides a more sensitive and
selective method than HPLC/UV because of the natural strong fluorescence of
PAH. The sensitivity of the method allows the quantitation of PAH in the 10
to 100 picogram range, using the flow cell connected to the detector and the
-------
- 117 -
s^top flow technique which permits the use of variable wavelength detectors.
The only major potential problem that might arise from this method is lack of
knowledge of the limitations of the detectors.
Gas chromatography/mass spectrometry;
This method, which combines gas chromatography with mass spectrometry
and computer, has long been preferred for the analysis of complex organic
mixtures. It has been used to analyze PAH content in airborne pollutants
(Lao et. al., 1973, 1976; Karasek et al., 1978), in sediment and combustion
systems (Hase et al., 1976), in coal tar distillates and in residues
(Sharkey et al. , 1975). The system of choice according to one investigator
(Lao et^ al^. , 1976) is the use of GC-FID-quadrapole MS-computer in analyz-
ing for PAH in air samples. The detection limit of GC-MS varies with the
MS unit, from ng to pg range.
Sample preparation, extraction and sampling should be carried out with
care to prevent any contamination. Computerized data accumulation and re-
duction allows for subtraction of spectral background to prevent misinter-
pretation of mass spectra and for the analysis of a large number of PAH in
any one sample CLao et^ al_., 1976; Hase e_t al_., 1976). The availability of
pure reference materials is important for all of these determinations.
High pressure liquid chromatograph/mass spectrometry;
In this method, which is still in the experimental stage, HPLC is com-
bined with MS and computer (Jones and Yang, 1975; McLafferty et^ al_. , 1975;
Elbert elt al., 1976) . This method will be ideal for the analysis of PAH from
asphalt and coal tar pitch sources. An efficient interface system is still
under development. The protopype interface (McFadden et al., 1976)
is not efficient and at present is far inferior to GC-MS. However, develop-
ment of a better interface will eventually make the application of
-------
- 118 -
HPLC-MS mo.re efficient and convenient than GC-MS for PAH (Thomas and Lao,
1977). In addition to the analysis of a large number of PAH in any one sample
by use' of computerized data accumulation and data reduction of mass spectral
values, the HPLC will afford better separation and resolution, little or no
decomposition at room temperature, larger samples of PAH in general and iso.-
meric PAH in particular when compared to GC.
Other methods;
An integrated method (Jewell et al., 1974) which has been used for semi-
quantitative characterization of residual oils has potential application in
the analysis of PAH from asphalt. This method incorporates sophisticated
chromatographic techniques which separate the maltene fraction into resins,
oils, saturates and aromatics. Molecular sieves are used to separate n-paraf-
fins from other saturates. Gel permeation, GC, TLC, elemental analyses, IR,
UV, NMR, ESR and MS procedures are then used to characterize the types of
functional groups, quantity and types of chain and aromatic ring structures
and heteroatom distribution in the subfractions.
C. Monitoring
Monitoring of asphalt fume and coal tar pitch volatiles in the workplace
and in emissions into the environment requires special techniques of sampling
and analysis. The sample collected must accurately represent the complex ma-
terial investigated, and the material being analyzed must be related to the
biological effects which are of concern.
Monitoring procedures for urban air (Dong e_t al_., 1976; Fox and Staley,
1976; Pierce and Katz, 1975; Lannoye and Greinke, 1974; Lao et al., 1973),
water (Zafiriou, 1973; Warner, 1976) , soil (Giger and Blumer, 1974.), and occupa-
tional environments (Bj^rseth and Lunde, 1977; Ball e_t al_. , 1976; Greinke and
Lewis, 1975; White, 1975) need to be performed rapidly and reproducibly
-------
- 119 -
by technicians using standardized and relatively inexpensive equipment. The
monitoring of the occupational and urban environments requires both high and
low volume samplers, i.ev environmental and personal monitoring. The effective-
ness of the sampling procedure is influenced by a number of factors such as
the nature of the filter, the air velocity, and the sampling rate. These
factors which are considered in the selection and use of monitoring procedures
have been discussed by White (1972, 1975) in relation to coke oven emissions.
Of the analytical methods discussed in Section IV.B.3., GC-FID-quadrapole
MS-computer is best suited to the needs of monitoring procedures at present.
The HPLC-MS-computer method will, however, be the analytical choice of the
future.
-------
- 120 -
V. TOXICITY AND CLINICAL STUDIES IN MAN
Toxic effects of bituminous materials on humans have long been noted.
Effects on specific target organs, particularly skin, eyes, and respira-
tory system, are described in Section A. The effects of various forms of
exposure to asphalt, pitch, and combinations of these materials are dis-
cussed in Sections B and C. The effects of coal tar medications are con-
sidered in Section D.
A. Effects on Organ Systems
1. Effects of asphalt
a. Effects on the skin:
Almost no reports of clinical effects of asphalt without coal tar have
appeared in the literature. Some cases of dermatitis related to asphalt
exposure were mentioned by Baylor and Weaver (1968). The National Safety
Council (1974) suggests precautions in handling asphalt to avoid inflam-
mation and dermatitis. A single case of squamous cell carcinoma following
long exposure to native lake asphalt road materials was reported by Henry
(1947) .
b. Effects on the respiratory system:
Some increase in noncancerous respiratory disease, chiefly chronic
bronchitis, was reported by Baylor and Weaver (1968) in a survey of petrol-
eum refinery and other workers exposed to asphalt, as compared to unexposed
controls.
Respiratory symptoms including bronchitis, chronic cough, nose and
throat inflammation and congestion, and laryngitis were described by Zeglio
(1950) in workers exposed to native asphalt, possibly sometimes adulterated
with pitch.
-------
- 121 -
2. Effects of coal tar pitch
a. Effects on the skin:
A number of skin changes have been observed following exposure to pitch
alone or combined with asphalt or other factors. Most of the classic detailed
descriptions are found in the early literature (Oliver, 1908; Schamberg,
1910; Foerster and Schwartz, 1939; Henry, 1947; Ross, 1948; Fisher, 1953;
Combes, 1954; Eckardt, 1959) and continue to be cited. More recent de-
scriptions have also appeared (Lev et a!L., 1966; Hodgson and Whitely, 1970;
Hervin and Etnmett, 1976b). Based on these references, the biological effects
of coal tar pitch on human skin can be summarized as follows:
Tar or pitch, burns: Burns from hot pitch or tar are relatively common
CBarry e_t al., 1975) . Burn scars and other areas of epidermal atrophy may
be sites for later skin cancer (Swanbeck, 1971).
Allergic eczematous dermatitis: Allergic reactions occur in occupational
exposures, but more commonly result from use of coal tar medications.
Folliculitis, comedones, acneform lesions: These common lesions,
occurring after one month of exposure, are usually limited to the face, neck,
and upper limbs, but may also appear in areas such as the thighs which are
abraded by clothing. Sebaceous cysts may appear on the scrotum. These
lesions are attributed to blockage of follicles with tar and pitch and to
induced keratin production in the pilosebaceous unit. Spontaneous remission
occurs when exposure ceases. These effects can be reduced substantially with
preventive measures and good personal hygiene.
Tar erythema (photosensitization, "pitch smarts"): Crude coal tar and
coal tar pitch are photosensitizing (phototoxic) agents. Combined exposure to
dust or fumes from tar and pitch and to sunlight (actinic radiation) results
in a painful, stinging condition characterized by an immediate eruption of
-------
- 122 -
wheals (urticaria) and reddening (erythema) followed by epidermal injury. After
several episodes of phototoxic reactions, chronic hyperpigmentation may occur.
The photosensitization reaction usually begins within an hour of exposure to
light and pitch, and may continue for many hours after exposure. In some
cases, reexposure to sunlight in the absence of pitch within the next several
days will result in burning. The face, neck, and forearms, which are-usually
exposed, are most commonly affected. Peeling occurs in three to five days,
even in the absence of erythema. Exposure to high humidity, sweating, high
concentration of fumes (especially from overheating of pitch), wind, and
strong sunlight all seem to intensify the phototoxic reaction. Use of low
fume {"no burn") pitch is said to diminish the reaction.
Chronic hyperpigmentation (pitch melanosis): Chronic melanosis, or
darkening of the skin, may develop after five or more years of exposure to
coal tar pitch, and may accompany other skin changes. Melanosis may follow
repeated phototoxic episodes, but may also affect unexposed areas. Hypopig-
mentation occasionally follows chronic pitch photosensitization.
Chronic tar dermatosis ("shagreen skin"): This condition, an essentially
irreversible process affecting the forearms, back of neck, face, and hands,
usually requires at least ten years of exposure. Manifestations may include
keratin hyperplasia, effects of repeated photosensitization, telangiectasia,
pigment changes, and neoplasia (papillomas and keratoses.)
Neoplastic changes: Exposure to coal tar and coal tar pitch can result
in a variety of benign and malignant growths, principally on exposed skin
surfaces but often affecting the scrotum. Lesions associated with pitch
exposure include:
-------
- 123 -
Benign:
Keratoses and papillomas, basal or squamous-cell - horny growths,
fibroepithelial papillomas (skin tags), simple warts ("tar molluscum").
Keratoacanthomas - pitch acanthomas, pitch warts - often accompanied
by other proliferative lesions; sometimes misdiagnosed as squamous
cell carcinomas; sometimes considered precancerous; often regress
spontaneously.
Keratoses may develop within six months; papillomas and keratoacan-
thomas may develop as soon as six-months or as long as 41 years after
initial exposure. A study of excised pitch warts maintained in tissue
culture indicated that, although a high degree of polyploidy was as-
sociated with the cultured warts, the chromosomes were normal (Everall
et al., 1967).
Malignant:
Squamous cell carcinomas - epidermoid carcinomas, spinocellular or
prickle cell epitheliomas - can develop within 18 months to 34 years.
Basal cell carcinomas - basal cell epitheliomas, rodent ulcers- -
uncommon.
b. Effects on the eyes:
Acute or chronic symptoms of eye exposure to pitch have been reported
by Moret (1912), Foerster and Schwartz (1939), Fisher (1953), Barkov and
Prosetskii (1958), Crow et al. (1961), Lev et al. (1966) , Gmyrya et al.
(1970), Susorov (1970), Hervin and Emmett (1976a,b), and Emmett et al.
(1977).
Acute episodes of eye involvement from either pitch fumes or pitch
dust usually begin two to four hours after initial exposure (beginning of
work shift.) Symptoms may include reddening of the eyelids and conjunctiva,
-------
- 124 -
perhaps accompanied by swelling and spasms of the lids, and disturbed vision.
After exposure has stopped, symptoms continue to increase; within about twelve
hours the eyes may be matted shut, with a purulent discharge. In mild cases,
symptoms disappear within three days, although photophobia may continue
for one to two months in the absence of further pitch exposure. Attempts to
reduce the severity of the response may include wearing protective glasses
and working at night. Eye involvement may be minimized by reducing exposure
to pitch volatiles to levels below 0.2 mg cyclohexane solubles per cubic
meter. In dusty operations involving pitch, no signs of conjunctivitis
were observed at levels of cyclohexane solubles below 0.11 mg/m^.
Prolonged exposure to pitch dust or volatiles may result in chronic
conjunctivitis and corneal staining, reduction in dark-adaptation and in
corneal sensitivity leading to corneal anesthesia, restriction of the visual
field, and pterygia.
c. Effects on the respiratory ^ystern:
Exposure to coal tar pitch dust has been noted to result in acute upper
respiratory distress, such as nasal congestion, hoarseness, throat irritation
and swelling, and coughing reported by Susorov (1970) and Lev el; al_. (1966).
Increased mortality from chronic bronchitis, emphysema and lung cancer have
been reported in workers exposed to coal tar pitch volatiles (National Re-
search Council, 1972; Hueper, 1963; Hammond et al., 1976; Doll et al., 1965;
Konstantinov and Kuzminyuk, 1971; Redmond et_ al_., 1972; Lloyd, 1971; Okubo and
Tsuchiya, 1974; Sakabe e_t al., 1975).
d. Other effects;
Exposure to coal tar pitch has been related to disorders of various
organs. Functional stomach disorders including chronic gastritis in pitch
workers have been described by Mikheeva (1967). A greater risk of dental
-------
- 125 -
caries, leukoplakia and edema of the oral mucosa has been noted in tar and
pitch workers (Pekker, 1967).
Increased incidence of cancer of a variety of organs has been observed in
persons whose exposures included coal tar pitch. Sites include bladder
(Henry, 1947 ; Borneff, 1965; Zorn, 1966; Doll et al., 1972; Hammond
el: a^., 1976), kidney (Redmond et ajL., 1972), stomach (Hammond et ail., 1976;
U.S. National Institute for Occupational Safety and Health, 1973), intestine
(Lloyd, 1971), pancreas (Lloyd, 1971), larynx (Hammond et al., 1976; Guardascione
and Cagetti, 1962), and buccal cavity, pharynx, and esophagus (Hammond et al.,
1976).
Most pitch workers are also exposed to other potentially carcinogenic
materials such as coke oven emissions (Lloyd, 1971; Redmond et al., 1972),
or lower-boiling fractions of coal tar such as basic fractions or creosote
(Doll et al., 1972). Also, the influence of coal tar pitch may be modified
by other factors such as smoking history or exposure to sunlight or other
ultraviolet light (Bingham et al., 1976; Emmett, 1973, 1975).
Bladder cancer is generally thought of in relation to exposure to aro-
matic amines which are present in appreciable quantities in some of the
lower-boiling fractions of crude coal tar, but are not major components of
coal tar pitch. For instance, Doll et al. (1972) reported the case histories
of 12 men who died from bladder cancer after being employed in gas works.
However, a few cases appear to involve exposure only to coal tar pitch.
Borneff (1965) reported a case history of a 62-year old tar distillery worker
with no known work contact with aniline or other low-boiling tar fractions,
who had pitch warts for several years preceding symptoms of bladder cancer.
A case of bladder cancer in a road worker with exposure only to paving tar
-------
- 126 -
and asphalt was reported by Zorn (1966), who identified alpha- and beta-
naphthylamine in the "paving tar" (pitch). In both cases the workers had
been exposed about 15 years before developing symptoms of bladder cancer.
In neither case did the men smoke or have known chronic exposure to any
potential carcinogen except pitch and tar.
B. Effects of Occupational Exposure
As early as 1775, Percival Pott recognized that the scrotal cancer
of chimney sweeps was a result of occupational exposure to soot. More re-
cently, Henry (1947) assembled data relating cases of skin cancer reported
in Britain from 1920 through 1945 to numerous occupational exposures, many of
which included coal tar and similar materials.
In-evaluating the carcinogenic potential of asphalt, coal tar pitch and
similar materials, it is important to consider the multiple factors which
may contribute to potency (Bingham et al., 1976). Ultraviolet radiation (UV),
itself generally considered-to be carcinogenic (Emmett, 1973, 1975), may aug-
ment the carcinogenicity of PAH in pitch or other bitumens. The relationship
of photosensitization to development of cancer is not known. On the other
hand, the action of UV, or of carcinogens present in bitumens may be modified
by other components which may act as cocarcinogens or as inhibitors. Such
compounds may be PAH or heterocydic aromatics closely related to the car-
cinogens, or phenolic or other materials whose role is not yet clearly under-
stood. In addition, other environmental factors, such as smoking and pol-
luted air, may have an important influence on the carcinogenicity of bitumens.
1., Exposure to asphalt
a. Refineries;
Baylor and Weaver (1968) surveyed the health of 462 asphalt workers in
25 petroleum refineries and of 379 controls. Each worker had been engaged
in asphalt work for at least five years, the average being 15.1 years. No
-------
- 127 -
significant differences in health were found, although there was some
dermatitis and other noncancerous skin disease, none severe, and an increased
incidence of chronic bronchitis and other noncancerous lung disease in the
asphalt workers.
In a study of Russian refineries, Kireeva and Yanysheva (1970) found the
highest levels of BaP around areas where higher boiling crude oil fractions
were being further processed. BaP concentrations reached 2.58 ;ig/m3 in the
asphalt processing area and 36.59 jig/m3 in the asphalt coking area. Other PAH
identified in these two areas were dibenz(ahVanthracene, benz(a)anthracene,
dibenz(ac)anthracene and anthracene. Of these, dibenz(ah)anthracene is con-
sidered a strong carcinogen, anthracene is noncarcinogenic, and the other
two are weakly carcinogenic. The incineration of gases from the air blowing
operation reduced the BaP concentration only from 1.1 ug/m3 to 0.84 pg/m3.
(Kireeva and Yanysheva, 1970).
b. Other;
In 1947, Henry reported one case of squamous cell carcinoma in a man
exposed for 22 years to native lake asphalt road materials. Zeglio (1950) des-
cribed respiratory symptoms in most of 22 electrical insulation workers using
native asphalt heated to 120°C. Symptoms, including bronchitis, chronic cough,
nose and throat irritation, breathing difficulty, rhinitis, and laryngitis,
improved when not working. Occasionally the asphalt may have been adulterated
with pitch.
In connection with a survey of the health of asphalt workers in refineries,
Baylor and Weaver (1968) assembled inforamtion about instances of ill health
attributable to asphalt exposure related to paving or roofing work or driving
over asphalt highways. Except for several cases of dermatitis and minor nasal
irritation, no cases of asphalt-related disease were reported by 31 construction
or paving companies, 15 state highway commissions and boards of health, three
-------
- 128 -
large roofing companies, four large trucking companies, and six insurance
companies.
2. Exposure to_coal tar pitch
In contrast to asphalt, exposure to coal tar pitch may result in clearly-
defined biological effects.
a. Exposure during production of pitch:
During the production and processing of pitch-containing crude coal tars
at coke ovens, tar distilleries, gas works, and other coal conversion plants,
workers may be exposed not only to pitch, but to a variety of noxious gases,
fumes, emissions, and lower-boiling tar fractions, as well as to sunlight
and cigarette smoking. Because of the multiple factors involved in these
exposures, the role of the pitch fraction in the production of biological effects
is not clear. Epidemiological studies of coke oven workers indicate in-
creased mortality from cancer of the lung (Lloyd, 1971; Redmond e_t al. 1972;
Okubo and Tsuchiya, 1974; Sakabe et^ a^., 1975; O'Connor, 1971), which is
greatly increased by cigarette smoking (U.S. National Institute for Occupa-
tional Safety and Health, 1973). Increased incidence of cancers of the
skin (Henry, 1947), kidney (Redmond e_t al^, 1972), and certain other sites
(Lloyd, 1971) have also been reported in coke oven workers.
An important relationship noted by Lloyd (1971) is that between the
temperature of coal carbonization (thus, composition of volatiles) and mor-
tality risk from lung cancer, as indicated in Table V-l. Mazumdar et al.
(1975) have reported a correlation between exposure (length of time and
work area) to coal tar pitch volatiles and development of cancer (particu-
larly cancers of the respiratory system) in coke oven workers.
Measurements of levels of PAH, BaP, or benzene or cyclohexane soluble
fractions of "coal tar pitch volatiles" (CTPV) have been made at coke, iron
-------
- 129 -
TABLE V-l. TEMPERATURE OF CARBONIZATION AND REPORTED
EXCESS OF LUNG CANCER
Percent
Temperature °C Type of Process Excess Lung Cancer
400-500 Vertical gas works retorts 27
900-1100 Horizontal gas works retorts 83
1200-1400 Coke Ovens 255
1500 + Gas generators
(Japanese) 800
Source: Lloyd, 1971
-------
- 130 -
and steel plants. However, it should be emphasized that the presence of such
materials, which may be found in a variety of tarry residues such as tobacco
smoke, charred food, asphalt fume, automobile exhaust, carbonized wood, and
cracked petroleum residues, does not imply that any or all of the PAH are attrib-
utable to coal tar pitch.
Some PAH levels measured near coke, iron and steel complexes do appear to
be related to the presence of pitch. When Masek (1971) sampled six Czecho-
slovakian coke plants, he found high levels of exposure of workers, especially
oven workers, to BaP. Table V-2 presents the data collected at one of the coke
plants (new at the time of sampling) which also carried on pitch processing,
including pitch coking.
In early studies in Britain, numerous cases of cancer of the bladder
(Henry e_t al_., 1931) and skin (Henry, 1947; Fisher, 1953) were reported in
workers at tar distilleries and gas works. Nonneoplastic skin changes
were also reported in tar distillers (Fisher, 1953). In later studies of
gas works employees, Doll ejt _al_. (1965, 1972) found increased risk of bronchitis
and cancer of the bladder, lung, and scrotum in men with high exposure to
volatiles from coal gasification. The risk of bronchitis appeared to be
greater in vertical retort houses (400 to 500°C) , while the risk of lung cancer
was higher in horizontal retort houses (900 to 1100°C) (Doll e_t al. , 1972) .
Spectrophotometric analysis by Lawther et_ aL_. (1965) of cyclohexane
soluble fractions of air samples taken in British retort houses revealed
acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene,
chrysene, benzo(e)pyrene, benzo(a)pyrene, perylene, anthanthrene, coronene,
benzo(a)anthracene, benzo(b)fluoranthene, and benzo(ghi)perylene. The
particulates were tarry droplets 0.1-1 pm in diameter. Continuous air and
personal monitoring of coronene, BaP, BeP, and benzo(ghi)perylene in-
-------
- 131 -
TABLE V-2. BaP CONCENTRATIONS AT A CZECJIOSLOVAKIAN PITCH PROCESSING
COKE PLANT
Sampling Point
Number of
Samples
BaP Concentration
Minimum Maximum
Average
Ascension pipes of
pitch battery
Collecting main of
pitch battery—
machinery side
Collecting main of
pitch battery—
discharge side
Medium pitch
pumping station
Tar distillation
pumping station
Administration
building
(indoors)
35
35
35
33
33
33
0.386 12.958
0.436 12.800
0.406 15.900
0.031
0.106
1.516
0.923
0.005 0.407
2.550
2.250
2.259
0.200
0.400
0.082
Source: Masek, 1971
-------
- 132 -
dicated that, although exposure levels varied widely within the retort house,
all workers were exposed to PAH levels higher than normal urban levels.
Gmyrya e_t .ajL. (1970) examined 152 coal tar chemical workers, the majority
26 to 45 years old, for signs of eye involvement from chronic tar and pitch
exposure. Most had symptoms of chronic exposure. Dark adaptation was below
normal in 71% of 112 workers tested. Disorders in corneal sensitivity appeared
soon and progressed with years of work. Complete corneal anesthesia was observed
in four eyes.
Mikheeva (1967) reported that half of 87 workers in the pitch depart-
ment of a byproduct coke plant had disturbances in basic stomach functions.
The incidence of functional changes was two to three times higher in pitch
workers than in controls. The changes were attributed to the effect of pitch
on the gastric mucosa.
In a study by Pekker (1967) the incidence of caries, leukoplakia and
observable changes in the oral mucosa was higher in the 547 tar processing
and coking workers than in controls from other parts of the plant. Free
oxygen tension in the oral mucosa was 3 to 4 times lower in the tar workers.
In addition to the effects resulting from exposure to products of con-
ventional coking of coal at coke ovens, gas works, and tar distilleries, tumors
were also observed in workers in a pilot plant for the hydrogenation of coal
(Sexton, 1960a,b). Samples of materials to which the workers were exposed also
produced cancer in experimental animals (Weil and Condra, 1960). This study
illustrates the fact that even with precautions for the health of workers,
tarry residues and other products of new coal conversion processes may be
hazardous to workers and users.
-------
- 133 -
b. Exposure Curing use:
(1) Electrodes:
As described in Chapter III, certain metallurgical electrodes, princi-
pally the anodes used for primary aluminum manufacture, are made of carbon-
aceous material such as petroleum coke as filler, with a large proportion of
coal tar pitch as a binder. During prebaking and use, thirty to forty per-
cent of the pitch binder is volatilized, producing a major source of po-
tential exposure to coal tar pitch volatiles. In an industrial hygiene
survey by Larsen (1973), air samples taken near potlines using prebaked anodes
had a range of total particulates from 0.90 to 8.96 mg/rn-^ and a range of
benzene solubles from 0.01 to 0.1 rng/m^. Personal air samples ranged from
0.7 to 30.4 mg/m-3 for composite total particulates and from 0.0 to 0.5 mg/m^
for composite benzene solubles. There is a tendency to replace the prebaked
electrode with the self-burning (Soderberg) electrode, which has not been
prebaked and thus releases all of its volatiles in the potroom during aluminum
reduction. Concern has been expressed over exposure of potroom workers to
coal tar pitch volatiles from the Soderberg electrode (Shuler and Bierbaum,
1974).
A study (Equitable Environmental Health, Inc., 1977) of the mortality
of aluminum workers, carried out for The Aluminum Association, Inc., has
provided epidemiological information that may be helpful in evaluating the
health effects of exposure to coal tar pitch volatiles. Records of 23,033
men who had worked five years or more in aluminum reduction plants between
1946 and 1973 indicated a slight positive association between employment as
-------
- 134 -
a potroom worker and lung cancer, most evident in workers in the horizontal
Soderberg process. Slight excesses of leukemia and lymphoma deaths in
these workers were not statistically significant. A significant excess of
deaths due to motor vehicle accidents was also observed in potroom workers.
The report suggests that the role of coal tar pitch volatiles in the health
problems of potroom workers should receive further study.
Konstantinov and Kuzminyuk (1971) examined mortality records over an
11-year period (1955 to 1966). Incidence of malignant neoplasms among furnace
operators, anode operators and crane operators (all subject to exposure from the
carbon anodes)was compared to the incidence in the population of the community
in which the aluminum plant was located. As shown in Table V-3, workers in
electrolytic shops that used Soderberg (self-burning) anodes had increased
mortality from cancer of all sites and cancer of the lungs, bronchi and
pleura. They also had an increased incidence of skin cancer. Workers at
the shop using prebaked anodes showed no increased mortality. Levels of BaP
at several shops utilizing different process technologies showed wide vari-
ation. The highest BaP levels (29.2 to 245 ug/m3) were seen in a Soderberg
shop with lateral current supply. Air-cooled anodes receiving overhead
current released fewer fumes, and thus less BaP, than uncooled anodes re-
ceiving overhead current. No BaP was detected in the prebaked anode shop.
Under all conditions, the highest levels of BaP were reached during furnace
processing and replacement of butts.
Substitution of petroleum pitch (a cracked petroleum residue) for coal
tar pitch in carbon anodes reduced BaP levels in the electrolytic shop.
Dust levels of BaP were reduced 7 to 24-fold when a petroleum pitch with 11.6
times less BaP than coal tar pitch was used (Konstantinov et al., 1973).
-------
- 135 -
TABLE V-3
INCIDENCE OF CANCER IN ALUMINUM WORKERS EXPOSED TO
SODERBERG OR PREBAKED ANODES
Soderberg anode:
(self-burning)
Prebaked anode:
Type
of
Cancer
All Sites
(mortality)
Lungs , Bronchi ,
Pleura (mortality)
Skin
(incidence)
All Sites
(mortality)
Age Group
(Yrs.)
All
18-39
40 +
All
18-39
40 +
All
18-39
40 +
All
18-39
40 +
Factor of Excess
Over Controls
1.85
7.15
1.57
1.7
8.3
no excess
10.5
38.8
6.6
no excess
no excess
no excess
Source: Konstantinov and Kuzminyuk, 1971.
-------
- 136 -
(2) Patent fuel (briquettes):
Workers handling pitch-containing coal briquettes in the sunlight de-
veloped phototoxic reactions of the eyes and skin, as well as upper respira-
tory symptoms (Lev et al., 1966)
Henry (.1947) reported 610 cases of squamous cell carcinoma in patent
fuel workers out of 3753 cases of job-related skin cancer. In 1931, Henry
et al. reported that the occupation of patent fuel laborer was one of the
two occupations with the highest death rate from bladder cancer, the risk
being four times greater than that for the male population of England and
Wales.
Skin lesions in 144 patent fuel workers exposed to coal dust and pitch
during 1957 to 1963, as compared to 263 controls (dermatological out-patients),
were described by Hodgson and Whiteley (1970). Photosensitivity was
recorded in 57% of the pitch workers and was unrelated to incidence of pitch
warts or acne. All acneiform lesions were much more common in the pitch
workers (93%) than in the controls (31%). There was little difference be-
tween the two groups in the incidence of benign proliferative lesions.
Squamous keratoses were slightly more common in the pitch workers (12%)
than in the controls (10%). Chronic tar dermatosis was found in 5% of pitch
workers with pitch exposure of 30 to 50 years, but not in controls. Squamous
cell carcinoma incidence was 2.8? in pitch workers compared with 0.4% in con-
trols. Pitch acanthoma developed in about 10% of the pitch workers; incidence
was related to duration of exposure, but also varied from 3 to 24% for low to
high levels of skin contamination with pitch; spontaneous regression was noted
in 26% of the cases. Scrotal proliferative changes were reported in 13.5% of
all the pitch workers, with 3.5% incidence of keratoacanthoma and one squamous
-------
- 137 -
carcinoma. Although incidence of some proliferative lesions increased with
increased exposure, the findings suggested that there is also a personal
susceptibility to pitch.
(3) Other
Blast furnace refractory brick: Levels of BaP ranged from 7 to 2500
Ug/m3 near a blast furnace lined with pitch-bonded refractory brick contain-
ing up to 15% pitch. In a survey of workers at this plant, Kapitul'skii
jet al. (1971) found that 22% of 149 workers had rashes on hands, face and
other parts of the body. None of the workers at another plant using less
than 1% pitch in the refractory brick had such symptoms. Tanimura (1968)
found high levels of BaP at several sites at an iron and steel complex.
The presence of pitch-refractory bricks might contribute to BaP levels near
the blast furnace, while tar or pitch used as a lubricant might have.con-
tributed to BaP levels near the pouring of steel into ingots or at the high
mills. Pitch was used as an open hearth fuel and as a binder in electrodes
used in the electric arc furnace, two other sites of BaP contamination.
Foundries: Levels of BaP at a Czech foundry were 1.2 ug/m3 in air,
0.100-14.04 mg/kg in sedimented dust, and 4.8-28.6 mg/kg in floor sweepings
containing coal tar. In an examination of 286 workers in two foundries for
signs of exposure to high BaP levels, Kolomaznik et^ al_. (1963) noted one
case of lung cancer, nine laryngeal neoplasms/ eight laryngeal pachydermas,
ten cases of leukoplakia and five unspecified pre-cancerous conditions.
Molded articles: Crow et al_. (1961) examined workers engaged in Holding
articles from pitch, asbestos and slate dust. Of the men exposed to pitch,
seventy percent developed comedones and forty percent had folliculitis of
the thighs. Seventy percent of the white workers reported pitch photosensitivity;
forty percent reported photophobia. More than half the men reported chronic
-------
- 138 -
"sweating yellow", which continued for three to seven days during vacations
and, in 25% of the workers, persisted up to two weeks after work exposure
to pitch had ceased. Henry (1947) reported one case of squamous cell carcinoma
in a man employed in the manufacture of clay pigeons.
Electrical conduits: Foerster and Schwartz (1939) reported that over half
of the 500 men at four separate plants had hyperpigmentation (melanosis) or
cutaneous lesions; comedones, folliculitis, keratoses, and papillomas were also
common, and squamous cell carcinomas were noted. Henry (1947) reported that
55 out of 3753 cases of occupational skin cancer occurred in workers manufacturing
or installing electrical equipment. Three cases of squamous carcinoma (two scrotal)
occurring in a group of 200 workers engaged for more than five years in the
process of "Stanford jointing" of earthenware pipes used as conduit for under
ground electric cable were described by Spink et al. (1964). Although the
jointing compound, which was applied hot, contained 20% coal tar, direct ex-
posure was considered limited and the liquid tar was considered less haz-
ardous than a dusty material. The cases were attributed to liberal skin con-
tact with a solvent-refined, petroleum-derived spindle oil used to protect the
pipe during jointing.
Pipe covering: Approximately ten workers were exposed to CTPV resulting
from the manufacture of a pipe coating using pitch, powdered polyvinyl chloride
and "petroleum tar," The benzene soluble fraction in personal air samples
(breathing zone) ranged from 0.18 to 4.41 mg/nv3. Sixteen out of seventeen
samples exceeded the OSHA standard of 0.2 mg/m3 (see Chapter VII), five
samples exceeded 1.0 mg/m3, and ten out of sixteen were at least double the
standard (Gunter and Ligo, 1976).
-------
- 139 -
Carbon Products: After twelve years of observation of a relatively stable
population of 170 workers making carbon products, Ross (1948) recorded a
total of 66 persons with folliculitis, comedones and acne, 25 with hyper-
pigmentation, 26 with chronic tar dermatosis, 102 with papillomas, and 16
with squamous cell carcinoma.
Floor laying: Abaseev et al. (1975) described a floor laying procedure in
which hot coal tar pitch was spread on concrete primed with anthracene oil,
wooden boards were pressed into place, and cracks were filled with dry pitch
applied with a hot iron (500°C). During this operation, the BaP levels in
the air might reach 0.24 mg/m3. Use of a catalytic after burner (at 400°C)
on the trapped fumes eliminated the hazard.
Commercial fishing: Henry (1947) reported skin cancers in workers ex-
posed to tar and pitch in fishing net repair and boat repair. Spitzer et al.
(1975) noted that commercial fishermen who had worked longer than eight sea-
sons had a 65% greater risk of lip cancer than other Newfoundland males of
comparable age. Analysis of other risk factors (such as outdoor exposure and
tobacco use) unexpectedly indicated that using the mouth as a "third hand"
to control tar-coated nets reduced the risk of lip cancer by fifty percent.
-------
- 140 -
3. Combined exposure to asphalt_and coal tar pitch
a. Roofing:
During both the laying and the tearing off of large commercial roofs,
workers are exposed to fumes and dust from both asphalt and coal tar pitch
which are used in various layers of built up roofing. It is not possible to
separate the contributions of the asphalt and the pitch to the "coal tar
pitch volatiles" or to health effects on exposed workers.
Air samples were analysed and roofers were examined in health hazard
evaluations of the tearing off of an old roof (Hervin and Emmett, 1976a) and the
laying of a new roof (Hervin and Emmett 1976b). During the tearing off operation,
levels of cyclobexane solubles from personal air samples varied from less than
0.01 to 1.88 mg/m3. Nine of fifteen men were exposed to more than the current
OSHA allowable level for coal tar pitch volatiles (0.2 mg/m3). The PAH levels
in the cyclohexane fraction varied from 0.059 to 0.247 mg/m3. Spectrometric
analysis of the pitch dust for PAH revealed 1.2 wt% anthracene/phenanthrene and
1.2 wt% fluoranthene. Other major components were pyrene, chrysene/benz(a)anthracene,
benzo(k)fluoranthene and benzo(a)pyrene/benzo(e)pyrene. Minor components in-
cluded acenaphthene and dibenzfuran. No alpha-or beta-naphthylamine was de-
tected CHervin and Emmett, 1976a).
During the laying of a new pitch roof using pitch heated to 190 to 204°C
(375 to 400°F), the cyclohexane soluble fraction varied from 0.02 to 0.49 mg/m3
in personal air samples on 26 workers and from 0.04 to 2:38 mg/m3 in area
samples. The average range of worker exposure to PAH was 0.017 to 0.083 mg/m .
A bulk sample of pitch used at the job contained 270 ppm BaP/BeP and 4.89 wt%
-------
- 141 -
cyclohexane solubles, of which 1.9 to 13 wt% was PAH. A bulk sample of asphalt
contained 10.3 wt% cyclohexane solubles, of which 0.5 to 3.2 wt% was PAH,
but no BaP/BeP was detected. Neither sample contained a- or g-naphthylamine
(Hervin and Emmett, 1976b). Tests of the carcinogenicity of these samples
to mouse skin (Bingham et a]L., 1977a) are described in Chapter VI.
In both operations, most workers had histories of skin photosensitization.
Phototoxic keratoconjunctivitis was common in both white and black workers,
and was subjectively associated with sunny days or summer (Hervin and Emmett,
1976a,b; Emmett et al., 1977). It was suggested that eye involvement in
roofing workers may be minimized by reducing exposure to pitch volatiles to
levels below 0.2 mg cyclohexane solubles/m3. In dusty operations involving
pitch, no signs of conjunctivitis were observed at levels of cyclohexane
solubles below 0.11 mg/m3 (Hervin and Emmett, 1976a).
In a study of mortality in 5939 roofers exposed to asphalt and pitch for
at least nine years before 1960 (Hammond et al., 1976; Selikoff, 1976), an
increase in lung cancer mortality, expected if inhalation of BaP is a cause,
was not observed until the time of exposure reached twenty years (Table V-4).
Smoking histories were not obtained. Mask filter BaP levels ranging from
"not detectable" to 135 ug/7-hr day were reported for all jobs at the work site,
with average exposure levels of 1.4-53 yg BaP/7 hr day (Hammond e_t aJU , 1976).
b. Paving;
Although bitumens for paving materials are now generally asphalt, varying
amounts of coal tar pitch have been used for this purpose. Cases of clinical
symptoms in road workers cannot readily be attributed to coal tar pitch or to
asphalt.
-------
- 142 -
TABLE V-4. MORTALITY RATIOS FOR SEVERAL CAUSES OF DEATH IN ROOFERS
Time in Roofing Union
Cause of Death 9-19 yrs. 20+ Yrs,
ALL DEATHS
Respiratory*
Accidents
ALL CANCERS
Buccal cavity, pharynx,
larynx , esophagus
Stomach
Bladder
Prostate
Leukemia
Lung
1.02
1.96
1.59
1.07
1.04
0.54
0.82
1.87
1.67
0.92
1.09
1.67
1.41
1.45
1.95
1.67
1.68
1.38
1.68
1.59
*Includes emphysema, chronic bronchitis and asthma.
Source; Hammond et al., 1976
-------
- 143 -
Zorn (1966) reported a case of bladder cancer in a road worker believed
to be exposed to pitch but not to other fractions of coal tar. Several brands
of paving "tar" were found to contain 0.3 to 3% B-naphthylamine, a known
bladder carcinogen, and half as much a-naphthylamine. The concentration of
3-naphthylamine was 1.5 to 4 ppm in the air near the tar spraying machine
and 20 pg (total) .in the worker's long underwear worn for six days without
washing.
4. Prevention of occupational disease
Detailed discussions of preventive measures needed to avoid occupational
disease from exposure to carcinogenic PAH that may be present in asphalt or
coal tar pitch can be found in the criteria document on coke oven emissions
(U.S. National Institute for Occupational Safety and Health, 1973 ), the pro-
posed and final standards on coke oven emissions (U.S. Department of Labor,
1975, 1976), and the criteria documents on asphalt fumes and coal tar products
(U.S. National Institute for Occupational Safety and Health, 1977a,b). The
following information is based on these references and on Bolton (1976),
Ketcham and Norton (1960), Crow et al. (1961), Garrett (1977), and Cheng (1977)
Prevention of any occupational disease can be broadly divided into four
areas of concern: education of employer and employee, medical surveillance,
protective devices or measures, and personal hygiene practices.
Education;
Fundamental to the prevention of occupational disease is the informed
worker. In order to protect himself and others, each worker must recognize
hazards in the workplace. A minimal program would involve displaying in a
-------
- 144 -
prominent place a clearly, simply written poster with the following informa-
tion: the generic names of substances to which workers are exposed, including
not only materials being handled, but major by-products that may be present;
possible' routes of exposure; acute or chronic symptoms of diseases that may
result from exposure; and personal measures the worker can take to minimize
exposure.
Medical Surveillance;
The surveillance program can include an educational program. Workers can
receive more detailed information on possible job-related difficulties as well
as information on avoiding occupational disease. This may include discussion of
the role of smoking and use of alcohol in predisposing workers to certain condi-
tions .
It has been suggested that the preplacement physical examination for
workers who will potentially be exposed to "coal tar pitch volatiles" include
the following: a complete medical history; tests of pulmonary function, in-
cluding forced vital capacity; chest X rays; sputum and urine cytologies;
urinalysis; blood count; and a complete skin examination, noting suspicious
lesions on a permanent record, ideally with photographs. Workers should have
annual physical examinations, with semi-annual checkups after age 45 or after ten
years of employment.
Protective devices or measures;
Engineering controls should be installed to eliminate exposure. Until
this is accomplished, or during situations involving high exposures, respirators
approved, by NIOSH or the Mining Enforcement and Safety Administration should be
worn.
Barrier creams may be helpful in avoiding skin contact, although there
is controversy as to their efficacy. Workers exposed to sunlight and pitch
-------
- 145 -
fumes should use a topical sunscreen, Five percent para-aminobenzoic acid
(PABA) in alcohol is recommended.
Goggles and garments which minimize skin contact with dust or volatiles
should be worn. Disposable clothing may be used.
Clothing that had been contaminated by pitch fumes during normal work
was found (Masek el: aJ., 1972; Kandus et al^., 1972) to contain 11.55 yg BaP/g
(average), while underwear contained an average of 5.47 vig BaP/g. PAH, as
indicated by BaP, accumulated in work clothing in spite of repeated washings.
For example, clothing laundered after every two work shifts contained an
average of 0.41 ug BaP/g clothing after two weeks, 0.86 yg BaP/g after three
months, and 3.15 yg/g after twelve months. Therefore, in addition to fre-
quent and thorough cleaning, garments should be replaced often.
It has been suggested that employers supply, launder and frequently
replace all work clothing, including boots and underwear. In this way,
clothing contaminated with potentially carcinogenic PAH can be handled by
supervised laundry personnel with adequate control of exposure, emissions
from dry cleaning, or effluents from laundering.
Personal hygiene;
After normal work, before doing anything else, hands should be washed.
After contaminations and after every work shift, workers should shower
thoroughly.
The use of waterless cleaners followed by soap and water has been re-
commended.
"Black light" (long wave ultraviolet) has been used for checking
workers after washing to detect any unremoved fluorescence. It is still
recommended by some (Bolton, 1976), but there is controversy over the
-------
- 146 -
benefit of regular exposure of workers to a potential carcinogen orcocar-
cinogen for the purpose of detecting other potential carcinogens.
C. Effects of Experimental Exposure to Coal Tar Pitch
The first experimental evidence that coal tar pitch is a photosensi-
tizing agent was presented by Foerster and Schwartz (1939). Patch tests
on the skin of pitch workers and controls under various physiological
conditions using pitch in a variety of solvents showed that in most subjects
pitch elicits phototoxic reactions to light with wave length from 390 to 500
nm. No reactions were seen to ultraviolet (UV) light less than 250 nm or to
infrared light. Sunlight filtered through window glass did elicit a photo-
toxic response. Patch areas which were washed before irradiation still showed
typical pitch photosensitization.
Crow et al. (1961) patch tested workers with pitch dissolved in chloro-
form. Most subjects complained of "pitch smarts" when exposed to light from
340 to 430 nm. The erythematous response in these workers was similar to
pitch phototoxicity seen in the field. The reactivity of a patch-tested area,
however, remained for several weeks rather than several days.
Individual components of pitch have been tested for their photosensitiz-
ing properties. Foerster and Schwartz (1939) reported phototoxic responses to
anthracene (strongest), acridine and phenanthrene, but stated that none of
these compounds alone was responsible for the phototoxicity of pitch. Crow
ert al. (1961) found that anthracene, but not acridine, regularly caused
phototoxic reactions in patch tests with light from 340 to 380 nm. Kaidbey
and Kligman (1977) reported that anthracene, fluoranthene and phenanthrene are
as phototoxic as coal tar.
-------
- 147 -
D. Effects of Experimental and Therapeutic Exposure to Coal Tar Medications
Crude coal tar preparations, long claimed to have useful antipruritic,
antiacanthotic, vasoconstrictive, keratoplastic and antiparasitic properties
(Obermayer and Becker, 1935^ are among the most commonly used dermatological
medications for the treatment of psoriasis, eczema, and other chronic skin
diseases (Gruber e_t al_., 1970), Such medications, with various trade names, are
formulated from crude (unfractionated) coal tar, which does not fall within
the scope of this report. Biological effects of crude coal tar medications
are included here because the properties related to their effectiveness
(photosensitization) and side effects (cancer) appear to be attributable to
their content (30 to 60%) of coal tar pitch.
When tested by continuous occlusive application to the backs of young
adult males for three weeks, 25% crude coal tar and undiluted coal tar dis-
tillate were equally acnegenic (Kaidbey and Kligman, 1974a). The lower
boiling fractions of coal tar seemed to be irritating, whereas the higher
boiling fractions, with keratoplastic properties, were most effective thera-
peutically (Obermayer and Becker, 1935). When application as a 5% mixture
in hydrophilic ointment to forearms of young adults was followed by exposure
to long ultraviolet light (UVA), crude tars were more phototoxic than par-
tially refined tars or liquor carbonis detergens.
According to Kaidbey and Kligman (1977), the antipsoriatic potential of
a tar parallels its phototoxicity, crude coal tars being more effective than
fractions thereof.
There is controversy about both the effectiveness and the safety of the
combined use of coal tar and ultraviolet light in treatment of psoriasis.
-------
- 148 -
Marsico and Eaglstein (1973) reported that crude coal tar and short-wave
ultraviolet light are more effective against psoriasis when administered
consecutively than when used separately. Young (1972) found that ultraviolet and
coal tar together produced no beneficial effect that tar alone could not have
conferred. He stated, however, that varying the concentration of coal tar used
with UV light may change the outcome of tar-UV experiments on psoriatic patients.
Coal tar and coal tar preparations have been tested for phototoxicity
and photoaugmentation, without regard for antipsoriatic potential. Crow
et al. -(1961) saw no photosensitization using crude coal tar and light.
Liquor Tpicis carbonis, a standard refined tar preparation, caused phototoxic
effects at 340-380 run in most subjects tested. Everett and Miller (1961)
tested tars derived from anthracite coal and bituminous coal and reported
that the photosensitization reaction depends not on the source of the tar,
but on exposure to light of wavelenth 350-400 nm.
Zesch (1972) reported that subjects had photosensitization reactions
following tar baths and exposure to light from 340-360 nm. In order to
determine how deeply the tar preparations penetrated, he examined excised
human skin painted with several standard tar preparations. Fluorescence
was observed in the horny layer of skin.
Kaidbey and Kligman (1975) reported that.photoaugmentation may be an
aspect of photosensitization. UVA (long ultraviolet) and UVB (280-320 nm)
administered in any order within a six hour interval will produce sunburn in
smaller doses than either administered alone. Application of coal tar
followed by irradiation with UVA, then UVB, augmented the phototoxic reaction
-------
- 149 -
to'coal tar in the majority of subjects. Damage at the microscopic level
was more pronounced with coal tar and UVA plus UVB than with coal tar and
UVA alone.
Crow et al. (1961) and Kaidbey and Kligman (1977) reported that the
phototoxic response was eliminated by curtailment of the blood supply to
the area patch tested with coal tar or anthracene for several minutes prior to
and during irradiation. This result suggests that the photosensitization
reaction, at least in the case of coal tar and derivatives, is oxygen de-
pendent .
The photosensitizing capacity of crude coal tar was found to be related
to the penetrating ability of the vehicle, being highest in emulsion-type
vehicles, such as hydrophilic ointment, and almost abolished in lanolin or
polyethylene glycol (Carbowaxj (Kaidbey and Kligman, 1974b).
However, Suhonen (1976) reported a well-defined long lasting phototoxic
response when five percent coal tar was applied in a Carbowax base and
occluded for 24 hours.
Coal tar has repeatedly produced skin cancer in animal experiments (see
Chapter VI) . Workers exposed to coal tar and pitch have an increased risk of
skin cancer. Even so, no epidemiological studies have indicted the therapeutic
use of coal tar. Swanbeck (1971) found that the frequency of psoriasis and
eczema (two conditions of epidermal hyperplasia commonly treated with coal tar)
is the same in populations with squamous cell carcinomas as in noncancer
populations. He also noted that squamous cell carcinomas sometimes develop at
scar sites, and suggested that epidermal hyperplasia of psoriasis and eczema,
in contrast to the epidermal atrophy of scars, may not predispose a site to
cancer.
-------
- 150 -
An international survey indicated that dermatologists have very strong
clinical impressions that cancer of the skin is not a problem in patients treated
with coal tar preparations. A psoriasis questionaire suggested that coal tar
does not cause an unduly high incidence of skin cancer among users, although
some cancers were seen in patients who used coal tar medications in combination
with X-ray or other treatment (Skin and Allergy News, 1977).
Only a very few case histories of skin cancer possibly related to use of
coal tar medications have appeared in the literature. Rook et al. (1956) re-
ferred to five patients who allegedly developed cancer after application of
coal tar medications. He described the case of a sixty-year-old road worker
with no history of tar contamination who developed two squamous cell carcinomas
on his thigh after treating the area for 34 years with various tar ointments,
using about one ounce of tar preparation every two weeks. Greither et al.
(1967) reviewed thirteen previously published cases of human skin cancer
following prolonged application of therapeutic tar preparations (not all coal
tar), including the cases cited by Rook et al. (1956).
Recently, Zackheim (1978) commented on the earlier reviews and indicated
the need for long term animal tests with tar products in various bases. While
he considered tar preparations to be effective and reasonably safe dermatological
medications, he protested over-the-counter availability of these products for
prolonged self-medication.
-------
- 151 -
VI. BIOLOGICAL EFFECTS ON ANIMALS AND PLANTS
A. Effects on mammals and birds.
1. Poisonings:
In addition to the toxic effects of bituminous materials observed in
exposed humans, cases of poisoning have been reported in animals accidentally
exposed to coal tar pitch and other coal tar products, but not to asphalt.
A number of cases of coal tar poisoning in swine were reviewed by Kern-
kamp (1964), who considered the disease an acute one, often fatal, with liver
lesions as the most important indication. One source of exposure to coal
tar pitch was fragments of clay pigeons (made from powdered limestone and
coal tar pitch) deposited as long as 35 years earlier when the area was
used as a target range. Other sources included various materials coated or
joined with pitch, such as tarred pipelines, stone chips, and roofing paper.
Maclean (1969) described severe chronic effects on the growth rate and
on Vitamin A utilization by sows and new-born piglets, including some deaths
with hepatitis. The disease was attributed to unidentified components of
coal tar pitch used as a joint filler for concrete slab housing and as a
coating on granite chips for road use.
Lambers and Van Ulsen (1973) reported that 30 pigs developed ascites
(accumulation of serous fluid in the abdomen) as a result of chronic coal
tar pitch poisoning from pulverized briquettes placed in their sties by
the owner. Autopsy of one of the pigs revealed the enlarged mottled liver
typical of pitch poisoning.
2. Toxicity:
Studies of toxic effects have been reported for coal tar and pitch,
but not for asphalt.
-------
- 152 -
a. Coal tar and pitch
Young pigs (4 to 9 weeks old) fed powdered clay pigeon targets for up
to two weeks developed severe hepatic centrilobular necrosis and hemorrhage/
often fatal, with related hematologic changes (Libke and Davis/ 1967;
Davis and Libke, 1968). Clay pigeon material administered to goats in large
doses (total 675 to 1350 g) by stomach tube during a three week period was
not fatal, but produced non-hemorrhagic hepatic lesions and weight loss in
all animals (Libke and Davis, 1968). All levels of ground clay pigeons fed
to PeKin ducklings were found to be acutely toxic, with depressed growth
and dose-related gross abnormalities, chiefly edema, and characteristic
microscopic liver changes (Carlton, 1966).
The toxicity of a pitch-tar varnish containing no benzo(a)pyrene was
studied by Kudrin et al. (1968). The varnish, of unspecified source and
composition, was used for the waterproofing of logs to be transported by
floating in rivers and reservoirs used as sources of drinking water. White
mice receiving pitch-tar varnish daily for ten days in oral doses of 100 mg/kg
showed a decrease in weight gain with inconclusive effects on behavior
(toleration of load burden). In three-month studies, white rats receiving
the varnish in daily oral doses of 10 mg/kg or of 1 ml of an. aqueous solution
containing 100 mg/1 showed no changes in behavior, nervous system function,
blood chemistries, and general condition. The group exposed to 10 mg/kg
showed significantly decreased weight gain starting in the second month,
and pathological changes in several organs (not identified). The varnish
was considered harmless at a concentration of 5 mg/1, with a maximum per-
missible limit of 10 mg/1.
-------
- 153 -
Bokov et al. (1974) exposed male Wistar rats 24 hours per day for
90 to 150 days to air containing material volatilized at 40 to 50° C (104 to
122°F) from UKhM-N bitumen mastic (an asphaltic bitumen). Xylene (0.04 mg/m3)
was identified in the chamber air, while phenol and unsaturated hydrocarbons
were expected but not found. Bone marrow cells of the exposed animals showed
an increase in chromosome aberrations at the late anaphase-early telophase
stage, with an increased number of fragments and a decreased number of chromo-
some bridges .
Kovalenko (1965) found that injection of bituminous coal pitch into the
surgically exposed preputial sebaceous glands of male rats produced inflam-
matory epithelial proliferation, with metaplasia to stratified squamous
epithelium.
Although the phototoxicity of coal tar pitch affects a large proportion
of exposed workers (see Chapter V) , almost no studies have been conducted in
experimental animals. Skin painting studies have been directed primarily to
the investigation of carcinogenic! ty . Emmett et al. (1977) studied the effect
on rabbit eyes of roofing coal tar pitch volatiles prepared by collecting
vapors from a large sample maintained at 200°C. Instillation of 10 yl of
this distillate into the conjunctivae of rabbits maintained in UV-free
quarters produced only minimal or mild temporary irritation. Irradiation
2
with long-UV light (330-380 nm) at 2.0 x 102 joules/m shortly after conjunctival
instillation produced marked photophobia and severe keratoconjunctivitis.
-------
- 154 -
Phenolic compounds are often present in high concentrations in coal tar
fractions (anthracene oil, creosote oil) boiling below coal tar pitch. Such
fractions are toxic and may cause high mortality when administered repeatedly,
as in some studies of carcinogenicity described below. Some phenols may act
as cocarcinogens (Boutwell and Bosch, 1959; Tye and Stemmer, 1967}. Phenols
are present in only small amounts in hard pitch, but may occur in toxic con-
centrations in heavy tars or soft pitches which contain considerable amounts
of lower boiling material. Grigor'ev (1954, 1959) found that heavy tars from
Cheremkhovo coal, thinned with 30% benzene, produced high mortality in mice
when applied to the skin three times per week for six months. The severity of
the toxic reaction (.degenerative changes in internal organs including liver,
spleen, and kidney) was related to the phenolic content (20 to 34%), and
interfered with possible development of skin tumors (Table Vl-1). Likewise,
anthracene oil (lower boiling than coal tar pitch) and its chromatographic
fractions were found by Domagalina (1954) to be highly toxic when applied to
the skin of mice twice weekly for 16 to 45 weeks (Table VI-1).
-------
- 155 -
b. Coal tar medications;
Although crude coal tar ointments have been widely used for the treat-
ment of hyperplastic epidermal disease such as psoriasis, few experimental
studies have been performed to evaluate their side effects or to elucidate
their mode of action.
Stone and Willis (1969) found that application to rabbit skin of coal
tar USP (crude coal tar) as a 5% mixture with a hydrophilic ointment in-
creased the severity of experimentally produced bacterial infection. When
5% crude coal tar mixed with a triple antibiotic ointment was applied to
experimentally produced wounds of rabbit ears/ there was a 46% delay in
wound healing, with marked follicular hyperkeratosis around the wound (Stone
and Anthony, 1970).
Application of crude coal tar fractions with boiling ranges either be-
low or above 250°c at 15 mm Hg produced acanthotic changes (thickening of
the prickle-cell layer) in guinea pig skin. The acanthotic activity of
the fraction boiling up to 250°C at 15 mm Hg appeared to reside chiefly in
the neutral portion, which also produced moderate inflammation (Schaaf,
1957) .
In studies of the effects of locally applied therapeutic agents upon
epidermal protein and nucleic acid synthesis, application of crude coal tar
(15* in cottonseed oil) to guinea pig skin three times per day for four
days caused inhibition of epidermal amino acid incorporation (Freedberg, 1965)
Crude coal tar (6% in petrolatum) and a refined coal tar preparation
(Estar gel, 0.5% crude coal tar) were found to depress DNA synthesis in vivo
in. normal and proliferating skin of the hairless mouse. The effect was
greatly increased when the tar was applied in combination with near ujtra-
violet light (UVA, 320-400 nm) (Stoughton e_t air, 1978).
-------
- 156 -
"3. Carcinogenic!ty;
Investigations of the chronic effects of asphalt and pitch samples have
been concerned chiefly with carcinogenicity. Studies of exposure by skin
painting, injection, and inhalation are summarized in Tables VI-1, VI-2, and
VI-3, respectively. These tables include pertinent quantitative data (dosage,
duration, number of animals, tumor incidence, etc.) from the original articles.
The information in the tables is mentioned in the text under the appropriate
materials, but is arranged in the tables, and referred to in the text, by
author and year to simplify identification of the substance studied. Where
both asphalt and coal tar samples were included in the same study, data are
presented together in the tables to permit ready comparison of results ob-
tained under the same test conditions.
a. Introduction;
Because of their viscous nature, many asphalt or pitch samples must be
warmed or diluted with a solvent to permit satisfactory skin application or
injection. The results of such tests may be influenced by inadequate con-
tact of "solid" samples with tissues or by cocarcinogenic or inhibitory ef-
fects of solvents.
If the dosage and/or frequency of application is too high, the toxicity
of components of the sample (or the solvent) may produce high mortality be-
fore tumors can develop or may alter the pattern of tumor incidence by inter-
fering with normal growth.
-------
TABLE VI-1.
CARCINOGF.NICITY OF ASPHALTS, TARS, AND PITCHES APPLIED TO THE SKIN
Original
number of Concentration
Material % DaP Species animals vehicle Dosage Frequency
Asphalt"
" air reflnedb
"
" steam refined*"
* saturates C aromatlcsc
Asphaltd
Road asphalts8
M
Roofing asphalt
Coal tar
Coal tar fume condensate
i
Asphalts, road
paving (8)
Coal tar pitch.
roofing (2)
Asphalts, straight run (3)
mice
(C57 black)
M
M
M
H
n
H
rabbits
mice
rabbits
mice
(C57 black)
mice
mice
(Swiss)
»
mice
(SS-57)
white
68
50
20
63
50
250
50
6
50
50
218
58
177
in benzene
heated 75-100 mg
+9% toluene 20-30 mg
heated 75-100 mg
33 mg
in acetone
in acetone 1 drop
heated 1 drop
N
H
M
1:3 in olive
oil
101 in benzene 25 M!
9% in benzene
(filtered) "
40% in benzene
2x/wk
l-3x/wk
3x/wk
3x/wk
3x/wk
2x/wk
2x/wk
2x/wk
2x/wk
2x/wk
••
2x/wk
II
Ix/wk
Duration Number of skin tumors Reference
12 carcinomas Simmers at al..
1959
2 yr 1 papilloma Sinners, 1965a
2 yr 9 carcinomas "
IS yr 3 carcinomas *• 2 papillomas "
Ih yr 13 carcinomas 4- 13 paplllomaa Simmers, 1965b
lifetime no cancers Hue per, 1965
2 yr 1 carcinoma + 2 papillomas Hueper c Payne,
2 yr 1960
2 yr
2 yr no cancers "
..
22 carcinomas + 4 papillomas *
1 carcinoma + 5 papillomas Wallcave e_f al.,
1971
31 carcinomas + S3 papillomas "
19 mo 5 tumors Kireeva, 1968
1
M
Ul
-O
1
Asphalts, cracked (2)
99
13 tumors
(cont'd)
-------
TABLE VI-1. CARCINOGENICITY OF ASPHALTS, TARS, AND PITCHES APPLIED TO THE SKIN (cont'd)
Materials
% BaP Species
Original
number of Concentration
animals vehicle
Dosage Frequency Duration Number of akin tumors
Reference
Coal tar pitch mice
(SS-57)
white
Asphalt, straight run V) mice
(C3H)
Asphalt, thermal 0.08
Coal tar pitch 0.59 "
Raw coal tar pitch 0.62% "
Roofing pitch (coal tar) 0.064 "
Roofing bitumen 0.072 "
Roofing pitch (asphalt) <0.0004 "
Coal tar? 0.67%
Coal tar from by 0.74% mice
product coke oven" C3II
Coal tar pitch from mice
Sllesian coals
", hard "
", soft
Pitch condensate (70% tar) ^ "
" deposits on snow*- "
49 40% in benzene Ix/wk
30 50% in triacetin 50 mg 2x/wk
30
30 " "
20 50% in toluene 50 mg 2x/wk
50 " 50 mg 2x/wk
50 " "
50 " "
30 50 mg 2x/wk
50 mg 2x/wk
48 1:1 in benzene 2x/wk
21
28 "
26 20% in benzene Ix/wk
19 mo 29 carcinomas + 8 paplllomas
(at 12 mo)
79 wk 1 benign
85 wk 7 malignant * 4 benign
41 wk 27 malignant
32 wk 14 " (100%)
45 carcinomas + 3 papillomas
39 " +0
no tumors at 49 wk
32 wk 28 malignant + 2 benign
100% tumors (82% malignant)
22 wk 14
" 8
14
15
5
Kireeva, 1960
Binghaa and
Feasley, 1972
t>
ft
Binghan and
Barkley, 1976
Btngham et al. ,
1977a
*
-
Bingha», 1975
Horton et al. ,
1963
Gorskl, 1959
•
"
Gorski « Malchar,
1965
I
t-1
(Ji
CD
1
(cont'd)
-------
TABLE VI-1.
CARCINOGEN 1CITY OF ASPHALTS, TARS, AND PITCHES APPLIED TO TIIE SKIN (cont'd)
Material % Bap
Heavy tars from 0
Cheremkhovo coal'
" k 0.01%
Coal tar chromatographlc
fractions
Pre-BaP
H
BaP
M
post-BaP (combined
results)
Anthracene oil
" Pre-BaP 0
" other fractions
* from Western U.S. crudes - pooled 3
3 pooled from Western U.S. crudes -
c pooled saturates and aromatics from
d native, straight run, air blown
* from 4 crudes
' condensed from coal tar vaporized eL
9 sample same as Bingham et al., 1977b
sample same as for inhalation
benzene extract
J 20-34% phenols
27% phenols
Original
number of Concentration
Species animals vehicle Dosage Frequency Duration Number of akin tumors Reference
vice 174 3x/wk 6 moo 2 cancers + papillomas (high Grigor'ev,
(white) mortality) 1954
" 64 30% in benzene " "no tumors in 19 mo. (high Grigor'ev,
mortality) 1959
mice 20 16 wk 0
rabbits 5 "4 Berenblu* t
mice 20 " 10 Schoental, 1947
rabbits 5 "3
•lice 60 "5
rabbits 15 "8
mice 10 2x/wk 39 wk 1 tumor (high mortality) Domagallna,
1954 E
"21 " 28-41 wk 8 tumors out of 11 surviving 10
mice |
"25 " 16-45 wk 2 tumors (high mortality)
steam and 3 air-refined
not the same as a
3 steam refined Western U.S. crudes
250-275'F (121-135*0.
, and MacEwen, 1976 (inhalation)
-------
TABLE VJ-2.
CARCINOGENICITY OF INJECTED ASPHALT AND. COAL TAR SAMPLES
Material
Original Number
Species Route Concentration/ Dosage Frequency Duration Number of of Reference
Vehicle Animals Sarcomas
Asphalt from Western US crudes mice 1% in olive
pooled; 3 steam-refined (C57 black) sc oil
+3 «ir-refineda
Asphalt from Western US crudes " sc heated
pooled; 3 «ir-refinedb
Asphalt from Western US crudes " sc heated
pooled 3 steam-refined"
Steam-refined asphalt from " sc
California crudCj pooled
saturates and aromatica
2 x/wk 41 wk
0.2 ml then 1 x/wk 33M, 29F
200 mg single dose 25H, 25F
repeated
after 4 mo
200 mg single dose 25M, 25F
repeated after
3 mos, 9 days
0.5 ml single dose 20H, 27F
Simmers
8 et al..
1959
3 Simmers,
1965a
0
8 Simmers,
1966
1
o
1
0.25 ml every other 8 in- 26M, 23F
week jections
1 ml less than ill in- 12M, 16F
weekly jections
Road asphalts from
4 crudes0
it
Coal tar fume condensate
rats
(Bethesda
black)
mice
(C57 black)
im
im
int
50% in 0.1 ml biweekly 6 doses 200
tricaprylin
50% in 0.2 ml biweekly 12 doses 120
tricaprylin
1:3 in olive 0.15 ml " 6 doses 100
oil
3
13 Hueper
Payne
50
and
, 1960
a Sample sane ai in Sinners, 1964
b Sample not the same as in Simmers, 1959
c Results combined from separate tests
-------
TABLE VI-3,
CARClNOGENICITY OF INIIALED ASPHALT AND COAL TAR SAMPLES
Material
* Original
Species How tented Concentration Frequency Duration no. of
animals
Tumors
" JAX-CAF
75
carcinomas * 30 lung incl.
alveolargenlc carcinomas
10 skin *• 6 lung
Reference
Asphalt from Western
US crudes, pooled:
3 steam-refined
*3 air-refined"
Roofing asphalt
air blown, flash
point 392"F
Coal tar
Coal tar"
Coal tar*
", non-phenolic
fraction i
Coal tar9
ft
Coal tarh
mice
(C57 black)
ft
guinea pigs
rats (Bethesda
black)
guinea pigs
rats
mice
(C3H)
«
M
hamsters
»
rabbits
hamsters
rats
aerosol in
moist airb
smoke from
sample heated
at 250°FC
vaporized at
250-275'F
n
vaporized
at 800°C
t*
M
t tar- coated
(.coal dust
\
U n-dodecane
aerosol
30 min/day 16»i mo
5 days/wk
6-7>i hr/day 21 mo
5 days/wk
5 hr/day 2 yr
4 days/wk
ti n
0.30 mg/1 2 hr/day 35 wk
3 days/wk
0.20 mg/1 (9 wk) " 55 wk
then 0.12 mg/1
M « M
65 mg/m3 6 hr/day 14 mo
3 days/wk
r
\600 mg/m3
20 mg/m3 contlnoug 90 days
mice 1CR-CF-1
20
30
30
65
42
75
33
100
50
23
38
24
100
164
75
1 papillary adenoma
1 bronchial adenoma
no cancers of skin or lungs
n
It
M
5 squamous cell tumors (lung)
(1 carcinoma)
r4 adenocarclnoma
1 19 intrabronchial adenoma
l_10 squamous metaplasia
ill intrabronchial adenoma
1.2 equamous metaplasia
'lung (4 benign)
'skin (1 f ibrosarcoma)
(lung (4 malig., 2 benign)
'liver (2 malig., 4 benign)
some skin
no skin
10 skin incl. squamoua cell
Simmers,
1964
M
Hueper £
Payne,
1960
"
Morton
ct al.,
1963
Tye t
Stemmer ,
1967
M
Bingham
et_ al. , 1977b.
M
MacEwen,
1976
^cont'd.l
-------
TABLE VI-3.
CARCINOGENICITY OF INHALED ASPHALT AMD COAL TAR SAMPLES (Cont'd)
Materials
Coal tar + 20%BTXJ
Species How tested Concentration
nice
ft
1CR-CF-1 aerosol 10 mg/m3
JAX-CAF-1
Original
Frequency Duration .no. of
animals
Tumors Reference
Continuous 90 days 225 44 ok in * lung IncL alveolargenlc MacEwen,
carcinoma 1976
75 IB skin
hamsters
rabbits
Coal tar * 20%BTxl
rats
mice
H
1CR-CF-1 " 10 mg/m3
JAX-CAF-1
monkeys
rabbits
Tarry fumes from
combustion of
anodes of Al
electrolysis
Road dust from
tarred roads
(2% tar)
rats
mice
N
mice
C3H vaporized BaP content
at 400*C 1.4 Ug/1
(0.2-3.4)
A
dust cloud
(1-2 mg tar/day)
guinea pigs
rabbits
14
eo
6 hr/day 18 mos 75
5 days/wk (Incomplete)
1 skin
50 no skin tumors during "
14
10
80
continuous 11 mos 144
10 mos 99
4-6x/day 1 year 73
5 days/wk
22
4
1st 8 mos.
skin neoplasms Mestitzova,
1961
lung metaplasia of respiratory
epithelium (nodules at 5 no -*
neoplasms)
f39 skin cancers + 7 skin warts Campbell,
(45 lung tumors 1934
incomplete
Incomplete
cn
K)
* sample same as simmers, 1959
b inhalation only
c
inhalation with exposure of skin and food
not malignant
* 0.74% BaP» 4.5* phenols
* sample same as Morton, 1963
q 0.67% BaP; sample same as MacEwen, 1976 (without BTX)
0.67% BaP/ sample same as Bingham et al.f 1977b
also tested at 10, 2, and 0.2 m
-------
- 163 -
Fogs or fumes for inhalation may be produced by various procedures in-
volving heating to a wide range of temperatures which may influence the composi-
tion of the fumes. The failure of inhaled materials to produce malignant tumors
of the lung may be related to lack of susceptibility of the test species under
the specific conditions of exposure used, since coal tar samples known to be
highly carcinogenic to the skin have not always produced lung tumors in in-
halation studies, (Saffiotti, 1969).
Injections by subcutaneous, intramuscular, or intraperitoneal routes
are of doubtful significance because they do not represent a normal route of
human exposure. Tumors at injection sites have been attributed by some in-
vestigators (Hueper and Payne, 1960) to carcinogenic components of the samples
but by others (Shubik e_t al., 1962) to physical effects which are unrelated
to the composition of the material injected.
All of these factors may modify the carcinogenic potential of the samples
so that accurate evaluation is difficult. Comparison is further complicated
by use of various species and strains of animals differing in susceptibility
and in spontaneous incidence of tumors.
The extensive surfaces paved with asphalt and tar and the processes
used for their construction have been regarded (Hueper and Payne, I960;
Hueper, 1963) as potential sources of air emissions and surface run-off
water pollutants which may be harmful to human, health, particularly as possible
causes of cancer. The composition of such potential environmental con-
taminants under conditions of use has been discussed in Chapter II.
In an early study, Campbell (1934) exposed mice, guinea pigs, and
rabbits intermittently to clouds of a dust collected from tarred roads
(Table VI-3). The dust, containing about 2% of "tar", produced malignant
skin tumors in 45 to 70% of the surviving mice and an increased incidence
(59 to 80%) of lung tumors, including some malignancies. In spite of
-------
- 164 -
such early concern, few studies of bituminous materials have been carried
out in experimental animals.
b. Asphalt;
Hueper and Payne (1960) applied road asphalts derived from four
American crudes (Venezuela, Mississippi, Oklahoma, and California) to
mice by skin painting (Table VI-1) and to mice and rats by intramuscular
injection (Table VI-2). Skin application to a total of 250 mice produced
only 2 carcinomas and 2 papillomas. A petroleum roofing asphalt likewise
produced only 1 questionable carcinoma in 50 mice. Inhalation of fumes
from this material produced no lung tumors in 65 rats (Table VI-3). In a
later study (Hueper, 1965), no cancers were produced in mice by skin
application of straight-run petroleum asphalt, air-blown asphalt, or
natural Trinidad asphalt (Table VI-1). The results indicated to the
authors that asphalts do contain carcinogenic materials but that their
potency may be reduced by air-blowing or by dilution with natural asphalts.
A roofing pitch (petroleum asphalt) tested by Bingham et al. (1977a)
produced no skin tumors in 50 mice when applied to the skin as a 50% mix-
ture with toluene (Table VI-1).
Simmers and co-workers investigated the carcinogenicity to mice of a
series of asphalt samples prepared from Western U.S. crudes at California
refineries (Simmers et al., 1959; Simmers, 1964, 1965a,b, 1966). Although
dilution was sometimes necessary to produce adequate skin contact, some car-
cinomas resulted from skin painting (Table VI-1) of separate or pooled samples
of air- and steam-refined asphalts or of the pooled aromatic and saturate
fractions from steam-refined asphalt, which were believed to retain all of
the potential carcinogenic agents. The pooled sample from air-blown and
steam-blown asphalts, which had produced skin cancer, caused no respiratory
cancers when inhaled by mice (Table Vl-3), although other changes in the
-------
- 165 -
lungs were observed.
Wallcave et al. (1971) also studied the carcinogenicity of asphalt
samples. Eight road paving grade straight-run asphalts, not air-blown,
from U.S., South American, and Mid-East crudes produced only one carcinoma
and five papillomas when applied to the skin of a total of 218 mice (Table VI-1)
These asphalts were found to contain small amounts of most of 17 PAH (some
carcinogenic) which were found in higher quantities in two coal tar pitch
samples which produced skin tumors in over 90% of treated Tnice (Table VI-1).
A straight-run asphalt applied to the skin of mice by Bingham and
Feasley (1972) produced only one papilloma in 30 mice, while a thermal
asphalt produced seven malignant and four benign tumors in 30 mice. In
contrast, coal tar pitch tested under the same conditions (50% in triacetin)
produced 27 malignancies in 30 mice (Table VI-1).
Kireeva (1968) found that three straight-run asphalts (40% in benzene)
produced only five skin tumors in a total of 177 mice. Under the same
conditions, two cracked asphalts produced a total of 13 skin tumors in
99 mice, while coal tar pitch produced 37 tumors (29 malignant) in 49 mice
(Table VI-1) .
c. Tars and pitches derived from coal
(1 ) Coal tar;
The first example of experimental carcinogenesis was the production
of cancers at the site of painting of coal tar on the skin of rabbits
(Yamagiwa and Ichikawa, 1915, 1918) and mice (Tsutsui, 1918), The early
isolation of the carcinogen BaP from coal tar pitch by Cook et: a_l. (1933)
led to the association of BaP content with carcinogenic activity. Although
this association is still widely assumed, it is clear that other compounds
contribute to the potency of coal tar. Separation techniques used by
-------
- 166 -
Berenblum and Schoental (.1947) produced several fractions which were free
of BaP but were found to be carcinogenic to the skins of rabbits and mice
(Table VI-1).
•Biological studies often mention the use of "coal tar" without any
description of source, physical properties, or chemical composition. Con-
fusion in the terminology applied to coal tars and pitches makes comparison
of such studies difficult. It is clear, however, that many "coal tar" and
coal tar pitch samples are strongly carcinogenic, producing malignant tumors
of mouse skin in a large proportion of the test animals within a relatively
short time. This activity contrasts sharply with the low incidence and long
latent period of tumors from asphalt.
Coke oven coal tar was found by Hueper and Payne (1960) to be carcinogenic
when applied to the skin of mice and rabbits (Table VI-1). Fumes produced at
250 to 275°P produced no tumors of the. skin or lungs when inhaled for two years
by guinea pigs and rats (Table VI-3), but condensate from the fumes produced 26
tumors (22 malignant) when applied to the skin of 50 mice (Table VI-1).
Horton et_ al_. (1963) studied another coal tar sample, obtained from an
American by-product coke oven, which contained 0.74% BaP and produced 100%
incidence of tumors (82% malignant) within 16 weeks when applied to the skin
of mice (Table VI-1). Inhalation by mice for 35 weeks of an aerosol generated
from this tar at 800°C produced at least one squamous-cell tumor of the lung
(Table VI-3). Similar inhalation techniques were applied by Tye and Stemmer
(1967) to phenolic and nonphenolic fractions from this and another coal tar.
-»
Incidence in the lungs and trachea of squamous metaplasia, adenomas, and
adenocarcinomas appeared to be related to combined exposure to phenols and
PAH (Table VI-3).
A coal tar condensate, from which only the low-boiling benzene-toluene-
xylene (BTX) fraction had been removed, contained 0.67% BaP and was found by
-------
- 167 -
Bingham (1975) to produce 100% incidence of skin tumors in mice (Table VI-1).
A comparison of the potencies to mouse skin of this tar and its dilutions
with the potencies of the same concentrations of BaP indicated that the
carcinogenicity of this tar could not be attributed entirely to its content
of BaP. Inhalation of aerosols produced from the same tar, with or without
the B2X fractions, was studied extensively in various species by MacEwen
(1976) (Table VI-3). Aerosol particle sizes were determined. Measurement
of fluorescent material extracted from tissues was used as an indication of
retention of inhaled PAH at various exposure levels. Malignant skin tumors
were produced in mice and rabbits, to a limited extent in ;rats, and not in
hamsters.
Inhalation by hamsters of coal dust coated with the same coal tar was
found by Bingham e_t alV (1977b) to,induce a low incidence •.. "
of neoplasms of the lungs and skin (Table VI-3). Simultaneous exposure to
n-dodecane, a known skin cocarcinogen (Horton et al., 1957), enhanced the
incidence of tumors, including benign and malignant neoplasms of the lung
and liver.
(2) Heavy tars or pitches;
Some heavy tars or pitches produced by the coking of coal contain large
amounts of phenols or other toxic materials. Thus Grigor'ev (1954, 1959)
found that tars from Cheremkhovo coal caused high mortality which interfered
with possible development of skin tumors (Table VI-1).
Gorski (1959) reported that soft pitch and hard pitch from Silesian
coals produced more papillomas when applied to the skin of mice than did
anthracene oil or foundry pitch. Deposits (70% tar) from the surface of
pitch cooler pipes rapidly produced skin cancer in mice, while pitch cooler
emissions deposited on a snow surface produced some tumors with longer
survival (Gorski and Malchar, 1965) (Table VT-1).
-------
- 168 -
(3) Coal tar pitch:
Wallcave et al. (1971) reported that two roofing-grade coal tar pitches
from coke oven production caused epidermal carcinomas and papillomas in over
90% of treated mice when applied topically (Table VI-1). The content of 17
PAH and their alkyl derivatives was determined for these pitches and for
asphalt samples which had much lower PAH content and caused only a few tumors.
Roofing coal tar pitch with a low BaP content was found by Bingham ejE al.
(1977a) to produce a high incidence of tumors when applied to the
skin of mice (Table VI-1). Coal tar pitches for use as electrode binders
likewise caused very high incidence of malignant skin tumors in mice (Bingham
and Feasley, 1972; Bingham and Barkley, 1976) (Table VI-1).
Although electrode binders represent a major use for coal tar pitches,
the biological effects of the emissions from production and use of such
electrodes have received little attention. Mestitzova (.1961) exposed mice
to tarry fumes produced at 400°C from anode material (coke dust plus hard
coal tar) used for aluminum electrolysis. Measurement of fluorescence
indicated that PAH were readily eliminated from lungs and blood but tended to
accumulate..in the lungs during continuous exposure. Skin neoplasms were
produced as well as metaplasia of the respiratory epithelium (Table VT-3).
The use of coal tar pitch as a binder for coal briquettes has also
caused concern. Kireeva (1968) found that a coal tar pitch used for this
purpose produced 37 tumors (29 malignant) when applied to the skin of 49
mice (Table VT-1). In order to reduce occupational and environmental ex-
posure to this hazard, it was suggested by Kireeva and Yanysheva (1972)
that the pitch binder be replaced by straight run or cracked asphalts of low
carcinogenicity or that pitch containing briquettes be prebaked before use
as fuel,
-------
- 169 -
(4) Coal tar medications;
Pharmaceutical preparations containing coal tar and related tars have
been described by Obermayer and Becker (1935). Of these, liantral is a
crude coal tar containing all fractions boiling above 80°C C176°F), from
which solid carbon has been removed, Liantral CBeiersdorf-Hamburg) No. 429 B
with a BaP content of 5 mg/g is used for preparation of the dermatological
ointment Locacorten-Tar (Ciba-Geigy brand of flumethasone pivalate) which
contains 1.5% tar in a lanolin base, resulting in a BaP content of 0.23 mg/g.
This ointment was applied to the skin of 18 hybrid mice five times per week
for 1.5 months, then three times per week for 10.5 months for a total of 186
doses containing 4.3 mg BaP within one year. Papillomas, starting at 4
nionths, developed in 16 mice, with malignant tumors in 13 mice (Linnik, 1970;
Shabad e_t al., 1970).
Another crude coal tar preparation, pix lithanthracis, produced car-
cinomas of the skin in 54% of a group of 100 female NMRI mice when applied
to the skin as a 5% solution in dimethylsulfoxide. Application of two drops
three times per week was reduced to one drop once weekly after four weeks
because of toxicity; treatments continued, for two years. No papillomas or
squamous cell carcinomas were produced following similar treatment with a
new synthetic tar mixture prepared from very pure coal tar fractions (aromatic
hydrocarbon, oxygen, nitrogen, and sulfur compounds), omitting all known car-
cinogenic and photodynamically active compounds. The synthetic material was
as effective therapeutically as the usual coal tar preparation CHilfrich and
Mohr, 1972).
Although coal tar was not included, several other tar-containing skin
medications commercially available in Japan were found by Hirohata et'al.
(1973) to contain BaP and other PAH and to cause -cancer when applied to the
skin of female CF#1 mice three times per week for up to 630 days.
-------
- 170 -
(5) Other coal-derived tars;
Although coal tar distillates which do not include pitch are not
included in the scope of this report, it should be mentioned that some
such products may contain carcinogens or components which modify car-
cinogenic activity. Domagalina (1954) studied anthracene oil con-
taining chromatographic fractions free of BaP which were highly carcino-
genic to the skin of mice (Table VI-1).. Sail and Shear (1940) and Cabot
et al. (1940) found that fractions of creosote oil could accelerate
(basic fraction) or retard (phenolic fraction) the carcinogenic action
of BaP.
As alternative methods of fossil fuel utilization are developed, the
carcinogenic potential of tars produced by other coal conversion processes
should not be overlooked (Koppenaal and Manahan, 1976). Studies of the
carcinogenic!ty of such materials have been reviewed (TRW Systems and Energy,
1976; Hueper, 1963 Weil and Condra (1960) found that some materials, such
as pasting oil, from a pilot plant for a coal hydrogenation process were
highly carcinogenic to the skin of mice. The experimental studies of these
samples were correlated with observations of the health of workers exposed
to the same materials in the pilot plant (Sexton, 1960a,b).
-------
- 171 -
B. . Effects on other animals
In spite of the widespread use of asphalt and coal tar pitch in paving,
roofing, and underwater coating materials, which offer great opportunity for
environmental contamination, their biological effects on species other than
laboratory and domestic mammals and birds have received almost no attention.
1. Fish;
Khosa and Chandrasekhar (1972) searched for an inexpensive material
to increase fish production by bringing about more rapid development of fish
eggs. They found that 50 yg of asphalt in saline injected intramuscularly
once weekly for 3 months enhanced maturation of ova and increased vitello-
genesis in the teleostean fishes Clarias batrachus and Ophicephalus punctatus.
The increased ovarian activity showed a correlation with changes in the fuch-
sinophil content of the neurons of the preoptic nuclei. Environmental ex-
posure to asphalt was not considered in the study.
2. Invertebrates;
A freshwater zooplanktonic copepod, Heliodiaptomus viduus, was used by
Ghosh £t al. (1974) to evaluate the acute toxicity of the combined effluent
of a coal tar mill manufacturing tar and bituminous emulsions. Toxic effects
were noted at tar waste concentrations of 0.05% or greater, with 50% mortality
at a concentration of 0.243%. It was concluded that the effluent requires
adequate treatment or high dilution before discharge.
C. Effects on vegetation-;
Damage to vegetation exposed to bituminous emissions has been studied
only in areas surrounding European mixing plants for bituminous (asphaltic)
road-building materials. Both Knosel and Rademacher (1964) and Kronberger
and Halbwachs (1975) found that the vapor and aerosol from the actual bitumen
-------
- 172 -
were not harmful to vegetation near the installations.
Kronberger and Halbwachs (19751 investigated the amount of bitumen
condensate that would have to be deposited on vegetation to produce
harmful effects. Damage to sensitive plants resulted only at experimental
^ O
levels =3.2 mg/100 cm of plant surface. Since the maximum level of bitumen
vapor condensate detected in the field near 21 Austrian hot-mix asphalt
plants was only 0.4-2.0 mg/100 cm^, it was believed that the level of emis-
sions was too small to cause damage to vegetation near the asphalt plants.
Damage actually detected in forests and other vegetation was attributed to
SQ2t 'dust, and soot rather than to the asphaltic bitumen vapors. It was
also suggested that dust might protect the plant surfaces.
Knosel and Rademacher (1964) likewise found that vegetation near mixing
plants for bituminous road-building materials was not damaged by the vapors
and aerosol from the bitumen. In rare cases, sensitive woody plants
exposed to the dust and smoke of the drying drum developed some leaf
discoloration and necrosis. Field crops and vegetables were not noticeably
damaged.
When vapors of tar components were tested on potato leaves, phenazine,
xanthene, and 2-methylanthracene were found to be phytotoxic. Acridine,
anthracene, fluoranthene, 9-methylanthracene and 9,10-dihydroanthracene were
phytotoxic only in the presence of sunlight. Acenaphthene, carbazole, chrysene,
fluorene, naphthalene and phenanthrene were nontoxic. Treating the leaves
with certain antioxidants (Ziram, Maneb, Dithane M45) eliminated damage by the
tar vapors (Halbwachs and Hlawatsch, 1968).
D. Effects on microorganisms;
The degradation of bitumens, asphaltic crude oils, and PAH by micro-
organisms in soil and water is briefly discussed in Chapter II.
-------
- 173 -
Mutagenesis; The Ames test of mutagenicity to Salmonella typhimurium
(Ames et al./ 1973) has been utilized to assess the mutagenic potential of
some coal tar fractions. Interest in the Ames procedure as a screening
test for carcinogenicity is a result of the correlation observed for many
materials between mutagenic activity in this test and carcinogenic activity
in biological tests using mammals. Wallcave (1975) reported that a small
number of mutations occurred with eight chromatographic fractions from coal
tar, and that the mutation rate was increased by microsomal activation.
Because the total number of mutations produced by polynuclear aromatic
hydrocarbons is small compared with the number produced by other classes
of compounds such as aromatic amines, Wallcave doubted the- '.adequacy of the
S. typhimurium strains for assay of polycyclic hydrocarbons.
E. In vitro studies
Photosensitization of cells by coal tar was studied in Hep-2 cells
from human laryngeal carcinoma. At least 1 1/2 hr of contact was required
for photosensitization. Firmness of bonding between coal tar and cells
increased with length of exposure (Freeman, 1970).
-------
- 174 -
VII. REGULATIONS AND STANDARDS
A. Current Regulations
Several government agencies have established regulations concerning
asphalt and coal tar, as set forth in the Code of Federal Regulations (CFR) .
1. Environmental Protection Agency
40 CFR 60.11 specifies that new asphalt concrete plants must limit particu-
late emissions to less than 90 mg/dscm (milligrams per dry standard cubic
meter) and less than 20 percent opacity (U.S. Environmental Protection Agency,
1974) .
40 CFR 443 establishes effluent limitations for pH, oil and grease, BOD 5,
and total suspended solids at new and existing paving and roofing materials
(tars and asphalts) point source subcategories: asphalt emulsions, asphalt
cement, asphalt roofing, and linoleum and printed asphalt felt (U.S. Environ-
mental Protection Agency, 1975b).
2. Department of Transportation
The Department of Transportation has recognized several names for asphalt,
including "asphalt," "road asphalt," "cutback asphalt," and "liquid road tar."
49 CFR 173.115 sets down the definitions of flammable, combustible and
pyrophoric liquids. Materials having flash points of 38°C (100°F) or below
are classified as flammable liquids, while materials having flash points be-
tween 38°C (100°F) and 93°C (200°F) are classified as combustible liquids.
In general, all grades of rapid-curing asphalts are considered flammable
liquids; most grades of medium- and slow-curing asphalts are combustible
liquids. Details on labelling and packaging requirements are specified by law
(U.S. Department of Transportation, 1975a).
-------
- 175 -
49 CFR 173.131 (a) (2) provides for continued use of nonspecification
cargo tanks equivalent in design to the MC 306 (49 CFR 173.340, 341) required
by law for transporting flammable liquids (U.S. Department of Transportation,
1975b).
3. Occupational Health Legislation in Various Countries
Of fourteen industrial nations surveyed, only five had legislation on
the manufacture and use of individual carcinogens. Of these five - Ireland,
Japan, the United Kingdom, the United States and the USSR - all except the
United States also have legislation forbidding the manufacture or importation
of specific individual carcinogens (Montesano and Tomatis, 1977). Whether
or not specific carcinogens are recognized and regulated by law, many countries
nonetheless have workmen's compensation acts for occupationally induced cancers
(Table VTI-1). There is no national policy in the United States for awarding
compensation to victims of occupational cancer, although individual states
may allow compensation for work-related disease - which may or may not include
cancer. It is estimated that less than five percent of all workmen's compen-
sation awarded is for occupational disease claims (Oil, Chemical and Atomic
Workers International Union, 1977).
Standards on asphalt and pitch: Because of its suspected carcinogenicity,
use of pitch as a paving material was prohibited in the USSR in 1950 (Gorbov
and Fomenko, 1962). Usage patterns in other nations appear to be economically
motivated. No regulations limiting use of asphalt were found.
4. Department of Labor, Occupational Safety and Health Administration (OSHA)
a. Coal_Ta.r_Pitch_ Volatile Standard
Table Z-l of 29 CFR 1910.1000 specifies that the eight-hour time-weighted
average for exposure to "coal tar pitch volatiles (benzene soluble fraction—
anthracene, BaP, phenanthrene, acridine, chryserie7 pyrene)" shall not exceed
0.2 mg/m . This standard does not apply to coke oven emissions.
-------
- 176 -
TABLE VII-1.
SOME RECOGNIZED OCCUPATIONAL CANCERS FOR WHICH COMPENSATION
IS GIVEN IN VARIOUS COUNTRIES
PAH
Skin
Country
BENZENE
Hematopoietic
System
AROMATIC AMINES*
Bladder
Australia +
Belgium +
Federal Republic + + +**
of Germany
France + + +
German Democratic
Republic +**
Ireland +
Italy + + +
Japan +
Switzerland +
United Kingdom + +**
*a-and jj-naphthylamine, benzidine, 4-aminodiphenyl
** Includes cancer of the urinary tract
Source: Montesano and Tomatis, 1977
-------
- 177 -
The interpretation of the coal tar pitch volatile (CTPV) standard
(29 CFR 1910.1002) reads as follows:
"..coal tar pitch volatiles include the fused polycyclic hydrocarbons
which volatilize from the distillation residues of coal, petroleum,
wood or other organic matter." (U.S. Department of Labor, 1972, 1977)
Ihe justification for including volatiles from distillation residues of
coal, petroleum, etc. is given as follows:
"Since all of these volatiles have the same basic chemical composition
and since all of them present the same basic dangers to a person's
health, the standard prescribed by [1910.1000] is applied to the use
of all of them." (U.S. Department of Labor, 1972)
Coke oven emissions: 29 CFR 1910.1029 sets the permissible exposure
limit at 0.15 mg/m^ for coke oven emissions, defined as the benzene soluble
fraction of total particulate matter (BSFTPM) present during the destructive
distillation or carbonization of coal. The Occupational Safety and Health
Administration considers the BSFTPM to be the same substance as the benzene
soluble fraction of coal tar pitch volatiles, at least those volatiles resulting
from coke production (U.S. Department of Labor, 1976). The proposed and final
standards for exposure to coke oven emissions discuss alternative approaches
to standards designed to regulate complex mixtures of particulates, vapors
and gases (U.S. Department of Labor, 1975, 1976). For this reason, the
information compiled for the coke oven standards should be reviewed before
the final technical standard for coal tar pitch volatiles is promulgated.
b. Coal Tar Pitch Volatile Standard Contested
On at least two occasions, OSHA has attempted to apply the CTPV standard
to asphalt fumes, in accordance with 29 CFR 1910.1002 - "Ccal tar pitch
-------
- 178 -
volatiles: interpretation of term."
Samples of asphalt emissions at two roofing manufacturing companies had
benzene soluble fractions in excess of 0.2 mg/m3, as well as detectable amounts
of BaPi The benzene soluble fractions ranged from 0.4 mg/m3 to 5.4 mg/m3; the
BaP concentrations ranged from 0.06 Mg/m3 to 0.6 yg/m3. Citations by OSHA were
successfully contested before the Occupational Safety and Health Review Commission
(OSHRC) by the Celotex Corporation, Cincinnati, Ohio (OSHRC Docket No. 15030)1-
and Bird and Son, Inc., Perth Amboy, New Jersey (OSHRC Docket No. 15553)2,
Thus there is currently no legal limit on asphalt fume exposure in the
workplace.
5. Department of Health, Education, and Welfare, National Institute for
' Occupational Safety and Health (NIOSH)
a. Criteria Document : Asphalt
NIOSH has prepared a criteria document on asphalt fumes, recommending that
the level to which any worker can be exposed should not exceed five milligrams
total airborne particulates per cubic meter of air, determined during any fif-
teen minute period. (U.S. National Institute for Occupational Safety and Health,
1977 a).
b. Criteria Document; Coal Tar Products
NIOSH has concluded that coal tar, coal tar pitch, creosote and any
mixture of these represent a carcinogenic hazard and has recommended that the
permissible exposure limit be the lowest concentration that can be reliably
detected by current methods. Thus, no worker should be exposed to any of the
coal tar products listed above, or mixture of these, in excess of 0.1 milligram
Personal Communication, Janie Brown, U.S. National Institute for Occupa-
tional Safety and Health, Cincinnati, Ohio.
2Personal Communication, Richard Niemeier, U.S. National Institute for
Occupational Safety and Health, Cincinnati, Ohio.
-------
- 179 -
of the cyclohexane extractable fraction per cubic meter of air, determined as
a time-weighted average for up to a ten hour shift in a forty hour work week
(U.S. National Institute for Occupational Safety and Health, 1977b).
c. Registry of Toxic Effects of Chemical Substances
The Registry of Toxic Effects of Chemical Substances (formerly the Toxic
Substances List) is prepared by NIOSH in compliance with requirements of Section
20 (a) (6) of the Occupational Safety and Health Act of 1970, Public Law 91-596.
There are entries for "asphalt" and "asphalt (cut back}," but none for "coal
tar pitch" or "pitch." The entry for "coal tar, aerosol" refers to the benzene
soluble fraction and includes the OSHA standard of 0.2 mg/m3, although the term
CTPy is not mentioned (U.S. National Institute of Occupational Safety and
Health, 1976)-
B. Consensus and Similiar Standards
1. National Safety Council (NSC)
The NSC considers asphalt a "substantially nontoxic" substance capable
of causing dermatitis in certain individuals. It recommends that protective
equipment (gloves, goggles) be worn and "personal cleanliness" be practiced
by individuals working with asphalt. Skin contact with asphalt and its fumes
should be avoided. The solvent vapor concentration of cutback asphalts should
be kept below the threshold limit value (National Safety Council, 1965).
For pitch and tar, NSC states that although these materials are known to
be producers of skin cancer, high incidences of skin cancer related to exposure
have not been reported, in spite of extensive investigations (National Safety
Council, 1974). No recommendations for use are given.
2. American Conference of Governmental Industrial Hygienists (ACGIH)
Threshold limit values of 5 mg/m3 for asphalt (petroleum) fumes and 0.2
mg/m3 for coal tar pitch volatiles (benzene soluble fraction) have been es-
tablished by ACGIH C1971). These values are not legally binding.
-------
- 180 -
VIII. TECHNICAL SUMMARY
Asphalt and coal tar pitch are widely used, durable, cementitious,
thermoplastic, water-resistant, bituminous materials. To enhance their
durability and versatility, both are used with a variety of materials,
including gilsonite, asbestos, epoxy resins, rubber, polyvinyl chloride,
mineral aggregates, petroleum coke, coal, creosote, and carbon black.
Although technological applications have changed, the basic uses of as-
phalt and pitch as binders, saturants, and weatherproof coatings have
persisted for centuries.
Because asphalt and pitch differ markedly in many important respects,
they must be discussed and evaluated as two distinct potential environ-
mental contaminants.
Asphalt
Petroleum asphalt is the uncracked residue from the fractional distil-
lation of crude oil. Natural deposits of asphaltic materials, occurring
world-wide, make up one to five percent of all asphalt consumed in the
United States. Gilsonite is the most commonly used native asphalt.
Commercial grades of asphalt are prepared to meet standard specifications
based on several physical properties, including softening point and viscosity.
Base stocks of asphalt can be formulated from an uncracked distillation residue
(straight-run asphalt), a residue of propane or butane deasphalting, or an air
blown asphalt (a stock through which air is forced at a temperature
-------
- 181 -
from 200 to 280°C). Liquid (cutback) asphalts are prepared by diluting base
stocks with solvents such as gasoline, naphtha, kerosine, or heavy diesel
fuel. Emulsions of asphalt and water are versatile, require less equipment
for use than cutbacks, and eliminate exposure to petroleum solvents.
Since 1970 annual asphalt sales in the United States have averaged 31
million tons. Seventy-eight percent of the asphalt is used in paving, 17% in
roofing, and 5% in miscellaneous applications (including dam linings, soil
stabilizers and electrical insulation).
Although plants manufacturing paving and roofing materials have generally
been considered a nuisance because of odor and dense haze, their emissions
have not been well characterized. Emissions from such plants and from asphalt
air blowing processes include entrained asphalt droplets, carbon dioxide,
carbon monoxide, sulfur oxides, nitrogen oxides, aldehydes, hydrogen sulfide,
traces of vanadium, nickel, cadmium and lead, as well as a variety of hy-
drocarbons. The large quantities of particulates emitted may contain up to
0.002% polynuclear aromatic hydrocarbons (PAH), including several carcinogens.
Ninety-nine percent control of the emissions is possible using currently
available thermal afterburners (fume incinerators) that retain the effluent
gas for 0.5 seconds at more than 816°C. The exhaust gas from the afterburner
can pass first through an oil-water gravity separator and then to a wet
scrubbing unit. The oil can be recovered from the gravity separator.
Water pollutants from the manufacture of asphalt materials have re-
ceived little attention. Water from scrubbing units used as the sole emission
control device at hot-mix plants can contain clay and mineral particles,
sulfuric acid, oil, gasoline, and asphalt.
-------
- 182 -
Installation of paving and roofing materials may be a localized source of
air pollution. Emissions from roofing operations can be greatly reduced by
maintaining the asphalt kettle temperature evenly below 216°C. Evaporation
of low-boiling hydrocarbon solvents from cutback asphalts contributes as
much as four percent of atmospheric hydrocarbon pollution in the U.S. Such
emissions can be entirely eliminated by the use of aqueous emulsions.
There are 1.7 million miles of asphalt covered roads in the United
States. It has been estimated that there are six billion tons of asphalt
covering roads, parking lots, runways and playgrounds. These surfaces are
subject to biological, chemical and physical degradation. Bituminous
(asphalt and pitch) highways may be a minor source of polycyclic aromatic,
heterocyclic, and metallic substances, possibly toxic or carcinogenic, in air,
waterways and sediments.
Limited animal skin painting and inhalation studies suggest that asphalt
may be weakly carcinogenic. No studies on its mutagenic or teratogenic
potential have been reported. Studies of exposure of plants, fish or other
organisms to asphalt are inadequate but have indicated no harmful effects.
Some microorganisms are capable of degrading asphalt»
Few human exposure studies are available. Mixed exposures to asphalt
and the more biologically potent coal tar pitch have been common in paving,
roofing and weatherproofing operations. It is therefore difficult to de-
termine whether workers are at risk from the asphalt. A few incidents of
contact dermatitis and respiratory irritation may have occurred; however,
it is generally agreed that asphalt is a relatively safe material to workers
under proper working conditions.
-------
- 183 -
The Environmental Protection Agency specifies that new asphalt hot-mix
plants must limit particulate emissions to less than 90 mg per dry standard
cubic meter and less than 20% opacity. Effluent guidelines for new and ex-
isting paving and roofing point sources (using tars and asphalts) regulate
levels of oil, grease and total suspended solids. The recommended standard
for occupational exposure to asphalt fumes is 5 mg airborne particulates/ m^
(U.S. National Institute for Occupational Health, 1977a). Although the
Occupational Safety and Health Administration standard on "coal tar pitch
volatiles" has been interpreted to include asphalt, the standard has not
been successfully enforced.
Coal Tar Pitch
Crude coal tar is a highly cracked product evolved during carbonization
of coal. All coal tar pitch commercially available in the U.S. is the residue
of distillation of by-product coke oven tar.
The amount of pitch produced annually has declined from 2,004,000 tons
in 1965 to 1,227,000 tons in 1976. About 62% of the pitch is used as a
binder or impregnant in carbon and graphite products. The largest single
carbon product market is for carbon anodes used in primary aluminum manufacture.
About 17% of the pitch produced is burned as an open-hearth furnace fuel.
Pitch (7%) is used for the manufacture of "tar" saturated roofing felt, as well
as cements used in the built-up roofing process on large, relatively low slope
commercial roofs. A stable market for pitch (10,000 tons annually) has been its
use as a binder in "clay pigeons" for skeet shooting. Pitch bonded and pitch
impregnated refractory brick used to line basic oxygen furnaces, blast furnaces
and foundry cupolas represent a steadily growing market.
-------
- 184 -
Pitch can undergo the same basic processing as does asphalt, namely
air blowing, dilution with coal tar solvents, or emulsification with water.
Air pollution control measures used for asphalt fumes can also be used to
contain emissions from pitch. Emissions from manufacturing processes using
pitch have not been thoroughly investigated. Large amounts of pitch dust
may be present as well as pitch volatiles. Large amounts of volatiles are
emitted during prebaking and graphitizing of pitch-containing carbon pro-
ducts such as electrodes. Emissions during use are higher for self-burn-
ing (Soderberg) electrodes than for those that have been prebaked or graphi-
tized before use. Pitch fumes usually contain, in addition to many other
compounds, carbazole, phenanthrene, anthracene, acridine, pyrene, and benzo(a)
pyrene. Pitch volatiles or coal tar volatiles can contain zinc, lead,
vanadium, cadmium, nickel, copper and chromium.
Workers exposed to pitch and sunlight often develop moderate to severe
acute phototoxic reactions of the skin. Effects of prolonged exposure to
pitch and sunlight have not been studied. Chronic exposure of the eyes to
pitch may lead to permanent changes.
Studies of human populations exposed to pitch and coal tar confirm that
these materials are skin carcinogens (U.S. National Institute for Occupational
Safety and Health, 1977b). Because fumes and particulates are inhaled during
exposure, increased incidence of lung cancer has been suspected, although
highly significant elevations have not been found in the limited epidemiological
studies reported. In workers exposed to pitch but not to other fractions of
coal tar, there may be an increased risk of mortality from cancer of the buccal
cavity, larynx, pharynx, esophagus, stomach, and possibly bladder. In complex
exposures such as coke ovens, gas works, and tar distilleries, the contribution
-------
- 185 -
of pitch to the observed increased cancer risk is uncertain. Even in less
complex exposures, the importance of multiple factors in cancer production
makes it difficult to evaluate the contribution of coal tar pitch to car-
cinogenic potency.
Although coal tar is generally known to contain carcinogenic PAH such
as BaP and to produce skin cancer in experimental animals/ medications
based on crude coal tar have been widely used for the prolonged treatment
of chronic skin diseases such as psoriasis and eczema. Few, if any, cases
of human cancer following such use have been documented, and few studies
o
'have been performed in experimental animals. The limited evidence available
indicates that such medications do contain carcinogenic PAH including BaP
and do cause cancer in treated animals.
Some components of pitch fumes are toxic to vegetation in the presence
of sunlight. The use of pitch to waterproof timber and water pipes may
result in the gradual solubilization of potentially carcinogenic polynuclear
aromatic hydrocarbons or other toxic substances.
Some attempt has been made to control worker exposure to emissions
from coal tar pitch. The present "coal tar pitch volatile" standard
(U.S. Department of Labor, 1977) specifies that worker exposure to air-
borne concentrations of pitch volatiles (benzene soluble fraction) shall
not exceed 0.2 mg/m^ averaged over an eight-hour work shift. The final
technical standard, when promulgated by the Department of Labor, will
delineate requirements for worker education, medical surveillance, personal
hygiene measures, and protective equipment (including respirators) as
well as accident, spill, fire and disposal procedures for any substance
defined under the standard. The current interpretation of the coal tar
pitch volatile standard covers volatiles from distillation residues not
-------
- 186 -
only of coal, but also of other organic materials including petroleum (i.e.,
asphalt). Because coal tar pitch volatiles are considered carcinogenic the
National Institute for Occupational Safety and Health (1977b) has recommended
a standard for occupational exposure to coal tar products, including coal tar
pitch, of 0.1 mg cyclohexane solubles per cubic meter of air (the lowest de-
tectable limits).
Examination of the literature indicates that the biological effects of
asphalt are probably limited. Large quantities, however, are processed and
the major uses are in roofing and paving products that are permanently exposed
to slow degradation in the environment. Coal tar pitch, on the other hand,
produces acute effects in a large proportion of exposed workers as well as an
increased risk of cancer of several sites after prolonged exposure. The
major uses of pitch involve occupational exposure, where workers can be pro-
tected and emissions can be controlled, rather than environmental exposure.
-------
- 187 -
IX. CONCLUSIONS AND RECOMMENDATIONS
Although asphalt and coal tar pitch are similar in certain physical
properties characteristic of bitumens, examination of the literature in-
dicates that they differ markedly in origin, composition, major uses, and
severity of biological effects. Therefore the two materials should be
handled separately in risk evaluation and in regulation of occupational ex-
posure and of emissions to the environment.
Although asphalt appears to be less harmful to humans and animals than
is coal tar pitch, the major uses of asphalt are in large surfaces permanently
exposed to weathering processes. The acute and prolonged effects of coal tar
pitch are more severe and may affect a large proportion of exposed workers.
If industrial emissions from pitch are controlled and use of pitch in exposed
surfaces is severely restricted, however, the overall contribution of coal tar
pitch to environmental pollution may be less than that of asphalt.
This report is limited to consideration of petroleum asphalt and coal
tar pitch. However, certain related materials may present similar hazards
and should be evaluated separately. Such materials include the distillate
fractions from crude coal tar and also the tarry residues produced from
other fossil fuel conversion processes.
There is reason to believe that the high boiling distillate fractions
of coal tar, such as creosote oil and anthracene oil, contain significant
amounts of carcinogenic PAH and have caused human and experimental cancers
when used, for instance, as lubricant oils in the metal-working industry.
As petroleum and asphalt supplies become insufficient for present and
future requirements, coal and oil shale conversion processes will probably
-------
- 188 -
increase, producing large quantities of tarry residues. Disposal of these
materials may present a significant problem. It will be tempting to use
such tars to replace asphalt as bitumens for paving and roofing, which would
result in large-scale exposure and environmental pollution. These tars re-
sulting from high temperature pyrolysis can be expected to be at least as
hazardous as coal tars obtained from present coking operations. Therefore
it is important that investigations should be conducted early enough to
ensure proper design of equipment and adequate protection of workers, the
public, and the environment.
Evaluation of the environmental and occupational hazards of asphalts and
tars is complicated by major inconsistencies in the terminology used by
producers, purchasers, users, epidemiologists, physicians, and experimental
scientists. "Asphalt;" as used here, refers to native asphalt or to the
distillation residue (petroleum asphalt), essentially uncracked, from straight-
, run processing of petroleum. This product is distinguished from severely
cracked petroleum residues such as petroleum pitch. "Coal tar pitch" is here
defined as the residual product remaining after distillation or stripping of
crude coal tar (a cracked material) formed during the coking of coal. Both
the origin and the composition of "asphalt" are thus distinct from those of
"pitch."
For the purpose of this report, terms such as tar, coal tar, coal tar
pitch volatiles, and PPOM (polycyclic particulate organic matter) are used
with caution. Clear and consistent definitions of terms for general use are
needed. Published reports of all original studies should include specific
-------
- 189 -
descriptions of the materials investigated so that comparisons with other
studies can be made.
Although a number of methods for sampling, analysis, and monitoring of
bituminous materials have been developed, few are well standardized or suited
for routine use. In particular, sampling devices should be improved, with
special attention to development of filters or other samplers that collect all
of the chemical substances and particle sizes under investigation. Procedures
for the determination of a greater number of individual PAH should be standard-
ized so that a variety of potentially hazardous materials can be monitored in-
stead of only BaP. Because of the health hazard of benzene, a safer solvent
should be selected for use in standard analytical procedures.
/
Although effective devices exist for the control of emissions from the
production and processing of asphalt and pitch and for some uses, they are not
always utilized. More data are needed on the actual levels of pollutants now
being emitted. There is a need for more energy-effective control devices and
for control of emissions during exposed uses such as roofing. Incentives for
adequate control of harmful emission are also needed.
Although isethods do exist for sampling and analysis of total particulates,
benzene solubles, and individual polynuclear aromatic compounds, no satisfactory
relationship has been established between the levels of the measured materials
and the degree of hazard from exposure to the asphalt or coal tar pitch sampled.
A few experimental studies have investigated the composition and biological
effects of asphalts and of coal tars. Such studies have indicated the rela-
tively low hazard of asphalt and the significant phototoxicity and carcino-
genic! ty of coal tar pitches. Although the effects of the two groups of materials
-------
- 190 -
are different, their physical properties are so similar that their uses over-
lap. Thus it is difficult to find human exposures to asphalt without simul-
taneous exposure to mixtures containing bituminous materials derived from coal
tar or from petroleum cracking operations, either of which are more hazardous
than asphalt. The problem of identifying asphalt as an entity distinct from
coal tar has been investigated by the U.S. National Institute for Occupational
Safety and Health (1977a) for the case of asphalt fumes. However, the only way
that workers or the public can profit from this distinction is by limiting or
excluding the use of coal tar in combination with asphalt, and at the same time
finding safe uses for the coal tar pitch.
The most serious hazard to human health from these bituminous materials
appears to be the carcinogenic potential of PAH present in the materials or
in the work environment during processing, application, and end use. While
the nature of the carcinogens is similar in asphalt and in pitch, the con-
centrations are much greater in coal tar pitch and other cracked residues
than in the relatively uncracked asphalt. Studies of correlation of bio-
logical effects with chemical composition and processing history of specific
samples would provide helpful information.
Measurable indexes of pollution such as benzene solubles, total particu-
lates, or respirable particulates which have been used or considered as stand-
ards for limitation of exposure are associated with widely different levels of
PAH in asphalt and in pitch. The proportion of carcinogen in the total PAH
may also differ. The possible cocarcinogenic effects of other components of
asphalt and pitch may also vary widely. Little information is available about
these multiple factors and their possible relationship in asphalt and in pitch.
Until such information has been obtained and verified in well designed experi-
ments, valid standards for safe levels of exposure cannot be established.
-------
- 191 -
To permit comparison and evaluation of experimental studies, the nature
of the material being tested should be specified clearly. Where possible,
exposure to asphalt and to pitch should be studied separately. Routes of
exposure should be similar to those found in humans. Inhalation studies are
particularly needed. Skin exposures to samples in various physical states
should be conducted to determine whether, as has been claimed, pitch dust is
more hazardous than liquid or pelleted forms. Samples of benzene solubles,
total particulates, or other materials which may be considered as the basis
of standards should be tested to determine whether their biological effects
actually correspond to their assigned level of hazard. In addition to being
tested for carcinogenicity, these complex materials should also be tested as
possible cocarcinogens or inhibitors of carcinogenesis. Because asphalt
and pitch are often used in combination with other materials such as mineral
aggregates, solvents, and other bitumens, the effects of such materials on
the biological properties of asphalt and pitch should be studied. The role
of multiple factors in the carcinogenicity of asphalt and pitch needs continued
emphasis.
Although less serious than carcinogenicity, phototoxicity is observed in
a large proportion of workers exposed to coal tar pitch. Studies are needed
to determine the causative agents in pitch, methods of protecting workers, and
possible chronic effects of repeated episodes of photosensitization.
Epidemiological studies are needed for industrial workers (pavers, roofers,
aluminum and other metallurgical workers) and for users of coal tar medications.
However, epidemiological studies of asphalt and coal tar pitch exposures may
be of limited value in identifying a causative agent because of the uncertain and
often mixed nature of the exposure. Since coal tar pitch appears to be more
-------
- 192 -
carcinogenic than asphalt, any exposure that includes coal tar pitch (such
as roofing) can offer little information about the possible carcinogenic
hazard of asphalt.
The initial need in epidemiological studies is the preparation of care-
ful job descriptions which can be correlated with route and degree of exposure
to specific materials. Such information is needed for roofing and paving jobs,
where exposure may be severe and accompanied by exposure to sunlight, and
hygienic facilities may be limited. This information may be particularly
difficult to obtain because records of job histories and materials handled are
inadequate.
The trace metal content has been studied extensively for petroleum, for
coal from various geographical sources, and for the emissions from combustion
of these fossil fuels. Little has been reported about the metal content of
coal tars to indicate whether any potentially toxic trace metals are being
concentrated in the tarry residue. More work is needed to determine whether
trace -metals constitute a hazard in asphalts and tars/ or whether such metals
will be leached appreciably under conditions of exposure during use of bitumens.
Present regulations by the Environmental Protection Agency limit particu-
late emissions from asphalt concrete plants and effluents from paving and roof-
ing material point sources. Because even small amounts of carcinogenic poly-
nuclear aromatic compounds contribute to the total carcinogenic burden to which
the public is exposed, emissions from both asphalt and coal tar pitch opera-
tions should be monitored and controlled.
Because of the immediate and long-term effects on the health of exposed
workers, there is a need for limitation of occupational exposure to coal tar
-------
- 193 -
pitch and possibly to asphalt. U.S. Department of Labor limitations of
occupational exposure because of possible carcinogenic hazard are based
on a definition of "coal tar pitch volatiles" which considers the benzene
soluble fractions volatilizing from distillation residues of any organic
materials, including petroleum as well as coal, as having the same basic
chemical composition and presenting the same dangers to human health.
Because the chemical composition of asphalt differs widely from that of
coal tar pitch, both quantitatively and qualitatively, the present standard
for coal tar pitch volatiles, with its definition including asphalt,
cannot be applied successfully to both materials. Separate standards are
needed for the control of exposure to and emissions from asphalt and coal
tar pitch.
-------
- 194 -
X. REFERENCES
Abaseev, V.K., Lebedev, M.A., Andreeva, G.S., Shaposhnikov, Yu.K., and
Kvasov, A.A. (1975). (Catalytic cleaning of gaseous products of the
thermal decomposition of coal tar pitch.) Gig. Tr. Prof. Zabol. No. 1:
12-14.
Adam, W.G. , Shannan, W.V. , and Sach, J.S. (1937). J. Soc. Chem. Ind.
56:414T. (Cited in McNeil, 1966a, p. 214).
Altgelt, K.H., and Gouw, T.H. (1975). ' Chromatography of heavy petroleum
fractions. In Giddings, J.C., Grushka, E., Keller, R.A., and Gazes, J.,
Eds.: Advances in Chromatography, Vol. 13, Chapter 3. New York, Marcel
Dekker, pp. 71-175.
Altgelt, K.H., and Harle, O.L. (1975). The effect of asphaltenes on
asphalt viscosity. Ind. Eng. Chem., Prod. Res. Develop. 14, No. 4:
240-46.
American Conference of Governmental Industrial Hygienists (.1971) . Asphalt
(petroleum) fumes. Coal tar pitch volatiles (benzene soluble fraction).
In Documentation of the Threshold Limit Values for Substances in Workroom
Air, 3rd ed. Stokinger, H.E., Chairman. Cincinnati, Ohio, ACGIH,
pp. 19-20, 57-58.
American Society for Testing and Materials (1973). Glossary of ASTM
Definitions, 2nd ed. ASTM Designation E-8. Philadelphia, Pa., American
Society for Testing and Materials.
Ames, B.N., Durston, S.W., Yamasaki, E., and Lee, F.D. (1973). Carcinogens
are mutagens: A simple test system combining liver homogenates for
activation and bacteria for detection. Proc. Natl. Acad. Sci. USA
70:2281-85.
Andelman, J.B., and Snodgrass, J.E. (1974). Incidence and significance of
polynuclear aromatic hydrocarbons in the water environment. CRC Critical
Reviews in Environmental Control 4:69-83 (Jan.).
Andelman, J.B., and Suess, M.J. (1970). Polynuclear aromatic hydrocarbons
in the water environment. Bull. W.H.O. 43:479.
Asphalt Institute (1973). Asphalt as a material. Information Series No. 93
(IS-93) , revised ed. College Park, Md., Asphalt Institute, 16 pp.
Asphalt Institute C1974a). Asphalt plant manual. Manual Series No. 3
(MS-3), 4th ed. College Park, Md., Asphalt Institute, 160 pp.
Asphalt Institute (1974b). A brief introduction to asphalt and some of its
uses. Manual Series No. 5 (MS-5), 7th ed. College Park, Md. , Asphalt
Institute, 174 pp.
Atlas, R.M., and Bartha, R. (1973). Fate and effects of polluting petroleum
in the marine environment. Residue Reviews 49:49-85.
-------
- 195 -
Ball, D.F., Clark, J., Ennis, J., Maynard, R., and Purnell, C.J. (1976).
Some measurements of air quality in garages specialising in the undersealing
of motor vehicles. Journal of Occupational Accidents 1:237-44.
Ball, J.S. (1965). Crude oil analysis as a guide to asphalt potential.
In Hoiberg, A.J., Ed.: Bituminous Materials: Asphalts, Tars, and Pitches.
Vol. II. Asphalts. Part 1. New York, Interscience Publishers, pp. 59-79.
Barbour, R.V., and Petersen, J.C. (1974). Molecular interactions of asphalt:
an infrared study of the hydrogen-bonding basicity of asphalt. Analytical
Chemistry 46:273-77.
Barkov, G.D., and Prosetskii, P.A. (1958). (Improving working conditions for
handling pitch at river and sea ports). Gigiena i Sanitariya 23, No. 12:
62-65.
Barry, T., and Associates (1975). Behavioral analysis of workers and job
hazards in the roofing industry. HEW Publication No. (NIOSH) 75-176.
Washington, D.C., U.S. Government Printing Office.
Bartle, K.D., and Smith, J.A.S. (1967). A high-resolution proton magnetic
resonance study of refined tars. II. High molecular weight fractions.
Fuel 46:29-46.
Bates, C.E., and Scheel, L.D. (1974). Processing emissions and occupational
health in the ferrous foundry industry. American Industrial Hygiene
Association Journal 35:452-62.
Baum, B., and Parker, C.H. (1974). Solid Waste Disposal. Vol. 2. Ann Arbor,
Michigan, Science Publishers, Inc.
Baylor, C.H., and Weaver, N.K. (1968). A health survey of petroleum
asphalt workers. Archives of Environmental Health 17:210-14.
Becker, R. (1969). Theory and Interpretation of Fluorescence and Phosphores-
cence. New York, Wiley Interscience.
Berenblum, I., and Schoental, R. (1947). Carcinogenic constituents of
coal-tar. British Journal of Cancer 1:157-65.
Berlman, I.B. (1965). Handbook of Fluorescence Spectra of Aromatic Molecules.
New York, Academic Press.
Berry, G.W. C1968). Roofing materials. In Kirk-Othmer Encyclopedia of
Chemical Technology, 2nd ed., Vol. 17. New York, Interscience Publishers,
pp. 459-75.
Berry/ W.L., and Wallace, A. (1974). Trace elements in the environment:
Their role and potential toxicity as related to fossil fuels. A preliminary
study. Los Angeles, California University, Laboratory of Nuclear Medicine
and Radiation Biology Publication No. UCLA-12-946, 72 pp.
Bhatia, K. (1971). Gas chromatographic determination of polycyclic aromatic
hydrocarbons. Analytical Chemistry 43:609-10.
-------
- 196 -
Bingham, E. (1975). Unpublished. University of Cincinnati, Cincinnati,
Ohio 45267.
Bingham, E., and Barkley, W. (1976). Comparison of carcinogenic properties
of coal tar and petroleum pitch and precipitated PPOM in 50% toluene.
Unpublished. University of Cincinnati, Cincinnati, Ohio 45267.
Bingham, E., Barkley, W., and Emmett, E. (1977a). Unpublished. University
of Cincinnati, Cincinnati, Ohio 45267.
Bingham, E., and Feasley, C.F. (1972). Unpublished. University of Cincinnati,
Cincinnati, Ohio 45267.
Bingham, E., Niemeier, R.W. , and Reid, J.B. (1976). Multiple factors in
carcinogenesis. Ann. New York Acad. Sci. 271:14-21.
Bingham, E., Stemmer, K., and Barkley, W. (1977b). The effects of inhalation
exposures to coal tar in hamsters. Unpublished. University of Cincinnati,
Cincinnati, Ohio 45267.
BjszJrseth, A., and Lunde, G. (1977). Analysis of the polycyclic aromatic
hydrocarbon content of airborne particulate pollutants in a S^derberg
paste plant. Am. Ind. Hyg. Assoc. J. 38:224.
Boden, H. (1976). The determination of benzo(a)pyrene in coal tar pitch
volatiles using HPLC with selective UV detection. Journal of Chromatographic
Science 14, No. 8:391-5.
Bokov, A.N., Guskova, S.I., Guskov, E.P., and Masko, V.I. (1974). (Use of an
anaphase method of estimating the chromosomal rearrangements in the bone
marrow in hygienic assessment of the mutagenic effect of building polymers.)
Gigiena i Sanitariya No. 8:17-20.
Bolotova, M.N., Davydov, Ya.S., and Nikishina, N.G. (1967). (Basic industrial
sources of the carcinogenic hydrocarbon: benzo(a)pyrene.) Meditsinskii
Zhurnal Uzbekistana 11:51-54.
Bolton, N.E. 01976). Industrial hygiene program for coal conversion technology.
In Abstracts of the First ORNL Workshop on Polycyclic Aromatic Hydrocarbons:
Characterization and Measurement with a View Toward Personnel Protection.
Oak Ridge National Laboratory Publication No. ORNL/TM-5598, Oak Ridge,
Tennessee, pp. 2-3.
Bondarava, E.N. (.1963) . Concentration of tarry substances in the atmospheric
air in the vicinity of an industrial coke-gas plant. USSR Literature on
Air Pollution and Related Occupational Diseases 8:89-93.
Bonnet, J. (1962). Quantitative analysis of benzo(a)pyrene in vapors coming
from melted tar. National Cancer Institute Monograph No. 9, pp. 221-23.
Borneff, J. (1965). Blasenkarzinom bei Teerarbeitern. (Bladder cancer in
tar workers.). Zentralblatt fur Arbeitsmedizin und Arbeitsschutz 15:288-92.
Borneff, J. (1975) . Fate of carcinogens in aquatic environment. American
Chemical Society, Division of Environmental Chemistry, Preprints 15; No. 1:
179-80.
-------
- 197 -
Boutwell, R.K., and Bosch, D.K. (1959). The tumor-promoting action of
phenol and related compounds for mouse skin. Cancer Research 19:413-24.
Braunstein, H.M., Copenhaver, E.D., and Pfuderer, H.S. (1976).
Environmental, health, and control aspects of coal conversion: An
information overview. Volume 1. U.S. Energy Research and Development
Administration, Oak Ridge National Laboratory, Publ. No. ORNL/EIS-94
(draft), Oak Ridge, Tennessee.
Breger, I.A. (1977). Asphalt and asphaltite. Natural occurrence.
McGraw-Hill Encyclopedia of Science and Technology, Vol. 1. New York,
McGraw-Hill, Inc., pp. 637-8.
Broche, H. , and Nedelmann, H. (1934). Gliickauf 70:979. (Cited in
McNeil, 1966a, p. 214).
Brooks, J.D. , and Stevens, J.R. (1964). Neutral components of higher
molecular weight in low-temperature coal tars. Fuel (London) 43:87-103.
Broome, D.C. (1965). Native bitumens. In Hoiberg, A.J., Ed.: Bituminous
Materials: Asphalts, Tars, and Pitches. Vol. II. Asphalts. Part 1.
New York, Interscience Publishers, pp. 1-25.
Broome, D.C. (1973). Bitumen. In Hobson, G.D., and Pohl, W. , Eds.:
Modern Petroleum Technology. New York, John Wiley & Sons., pp. 804-15.
Brown, P.R. (1973). High Pressure Liquid Chromatography. New York,
Academic Press.
Brunnock, J.V., Duckworth, D.F., and Stephens, G.G. (1968). Analysis of
beach pollutants. J. Inst. Petrol. 54, No. 539:299-314.
Burchfield, H.P., Wheeler, R.J., andBernos, J.B. (1971). Fluorescence
detector for analysis of polynuclear arenes by gas chromatography.
Analytical Chemistry 43:1976-81.
Burlingame, A.L., Cox, R.E., and Derrick, P.J. (1974). Mass spectrometry.
Analytical Chemistry, Fundamental Reviews 46:248R-287R.
Cabot, S., Shear, N. , Shear, M.J., and Perrault, A. (1940). Studies in
carcinogenesis. XI. Development of skin tumors in mice painted with
3:4-benzpyrene and creosote oil fractions. Am. J. Pathol. 16, No. 3:
301-12.
Camp, F.W. (1969). Tar Sands. In Kirk-Othmer Encyclopedia of Chemical
Technology, 2nd ed., Vol. 19. New York, Interscience Publishers,
pp. 682-732.
Campbell, J.A. (1934). Cancer of skin and increase in incidence of primary
tumours of lung in mice exposed to dust obtained from tarred roads.
British Journal of Experimental Pathology 15:287-94.
Carlton, W.W. (1966). Experimental coal tar poisoning in the white Pekin
duck. Avian Dis. 10, No. 4:484-502.
-------
- 198 -
Cerniglia, C.E. , and Perry, J.J. (1973). (Crude oil degradation by
microorganisms isolated from the marine environment.) Z. Allg. Mikrobiol.
13, No. 4:299-306.
Charette, L.P., and Bischofberger, G. (1961). Application of high vacuum
micro-distillation to the study of coal-tar and petroleum pitches.
Fuel (London) 40:99-197.
Cheng, R.T. (1977). Industrial hygiene program and experiences for a
50-ton/day SRC pilot plant. Workshop on Exposure to Polynuclear Aromatic
Hydrocarbons in Coal Conversion Processes. II. Industrial Experiences,
Personnel Protection, and Monitoring. Oak Ridge National Laboratory,
Oak Ridge, Tennessee, March 10-11.
Christenson, C.W. (.1968) . Treatment of low and intermediate level radio-
active concentrates. U.S. Atomic Energy Commission Document No. LA-DC-10005,
63 pp.
Clar, E. (1964). Polycyclic Hydrocarbons, Vol. I and II. New York, Academic
Press, 974 pp.
Coal Age (1976). NCA forecasts record coal output in 1975. p. 22.
Cogswell, I.E., McKay, J.F., and Latham, D.R. (1971). Gel permeation
chromatographic separation of petroleum acids. Analytical Chemistry
43:645-48.
Cohrssen, B. (1977). The use of coal tar pitches: a comparative analysis
of their hazards. Master's Thesis, University of Cincinnati, 117 pp.
Coleman, H.J., Cooley, J.E., Hirsch, D.E., and Thompson, C.J. (1973)
Compositional studies of a high-boiling 370-535°C distillate from
Prudhoe Bay, Alaska, crude oil. Analytical Chemistry 45:1724-37.
Combes, F.C. (1954). Coal Tar and Cutaneous Carcinogenesis in Industry.
Springfield, Illinois, Charles C. Thomas, 76 pp.
Commins, B.T., and Lawther, P.J. (1958). Volatility of 3,4-benzpyrene in
relation to the collection of smoke samples. British Journal of Cancer
12:351-54.
Cook, J.W., Hewett, C.L., and Hieger, I. (1933). The isolation of a
cancer-producing hydrocarbon from coal tar. Parts I, II, and III.
Journal of the Chemical Society (London) 1:395-405.
Corbett, L.W. (1966). Manufacture of petroleum asphalt. In Hoiberg, A.J.,
Ed.: Bituminous Materials: Asphalts, Tars, and Pitches, Vol. III. Coal
Tar and Pitches. New York, Interscience Publishers, pp 82-122.
Corbett, L.W. (1967). Distribution of heavy metals in asphalt residua.
American Chemical Society, Division of Petroleum Chemistry, Preprints
12, No. 2:A83-A87.
Corbett, L.W. (1969). Composition of asphalt based on generic fractionation,
using solvent deasphaltening, elution-adsorption chromatography, and
densimetric characterization. Analytical Chemistry 41:576-79.
-------
- 199 -
Corbett, L.W. (1975). Reaction variable in the air blowing of asphalt.
Ind. Eng. Chem., Proc. Des. Develop. 14, No. 2:181-87.
Couper, J.R. (1977). Asphalt. Analytical Chemistry, Application Reviews
1 49:240R-243R.
Crow, K.D., Alexander, E., Buck, W.H.L., Johnson, B.E., Magnus, I.A., and
Porter, A.D. (1961). Photosensitivity due to pitch. British Journal
of Dermatology 73:220-32.
Danielson, J.A., Ed. (1973). Air pollution engineering manual. U.S. Environ-
mental Protection Agency Publication No. AP-40, 987 pp.
Davis, J.W., and Libke, K.G. (1968). Hematologic studies in pigs fed clay
pigeon targets. Journal of the American Veterinary Medical Association
152:382-84.
Day, A.J., and Herbert, E.G. (1965). Anionic asphalt emulsions. In
Hoiberg, A.J., Ed.: Bituminous Materials: Asphalts, Tars, and Pitches.
Vol. II. Asphalts. Part 1. New York, Interscience Publishers, pp.
333-58.
DeMaio, L. and Corn, M. (1966). Gas chromatographic analysis of
polynuclear aromatic hydrocarbons with packed columns. Application
to air pollution studies. Analytical Chemistry 38:131-33.
Demann, W. (1933). Brennstoff-Chem. 14:121. (Cited in McNeil, 1966a,
p. 214).
DeStefano, J.J., and Kirkland, J.J. (1975). Preparative high-performance
liquid chromatography. Analytical Chemistry 47:1193-1204.
Dickinson, E.J. (19451. J. Soc. Chem. Ind. 64:121 (Cited in McNeil,
1966a, p. 214).
Di Corcia, A., Liberti, A., and Samperi, R. (1976). Gas chromatographic
analysis of aliphatic and aromatic hydrocarbons with 2,4,5,7-tetranitro-
fluorenone-modified graphitized carbon black. Journal of Chromatography
122:459-68.
Doll, R. , Fisher, R.E.W., Gammon, E.J., Gunn, W., Hughes, G.O., Tyrer, F.H. ,
and Wilson, W. (1965). Mortality of gasworkers with special reference
to cancers of the lung and bladder, chronic bronchitis, and pheumoconiosis.
British Journal of Industrial Medicine 22:1-12.
Doll, R., Vessey, M.P., Beasley, R.W.R., Buckley, A.R., Fear, E.G.,
Fisher, R.E.W., Gammon, E.J., Gunn, W., Hughes, G.O., Lee, K., and
Norman-Smith, B. (1972). Mortality of gasworkers - final report of a
prospective study. British Journal of Industrial Medicine 29:394-406.
Domagalina, E. (1954). (Biological activity of Polish industrial oils.
I. Anthracene oil.) Acta Polon. Pharm. 11:161-7, -
Donaldson, H.M. , Shuler, P.J., and Parnes, W. (1972). Walk through industrial
hygiene survey of Aluminum Company of America facilities. U.S. National
Institute for Occupational Safety and Health.
-------
- 200 -
Dong, M., Locke, D.C., and Ferrand, E. (1976). High pressure liquid
chromatographic method for routine analysis of major parent polycyclic
aromatic hydrocarbons in suspended particulate matter. Analytical
Chemistry 48:368-72.
Dorrence, S.M., and Petersen, J.C. (1969). Silylation of asphalts within
gas-liquid chromatographic columns. Effects on inverse GLC data and
infrared spectra. Analytical Chemistry 41:1240-43.
D'Silva, A.P., Oestreich, G.J. , and Fassel, V.A. (.1976) . x-ray excited
optical luminescence of polynuclear aromatic hydrocarbons. Analytical
Chemistry 48:915-17.
D'Silva, A.P., Oestreich, G.J., Woo, C.S., and Fassel, V.A. (1977). X-ray
excited optical luminescence of polynuclear aromatic hydrocarbons:
analytical potential. In Gammage, R.B. (.1977) , pp. 117-22.
Duswalt, J.M. , and Mayer, T. J. (.1970) . Separation and characterization of
methylethylnaphthalene isomers by chromatographic and spectrometric
methods. Analytical Chemistry 42:1789-94. ,,
Eckardt, R.E. (1959). Industrial Carcinogens. New York, Grune and
Stratton, 164 pp.
Elbert, S., Gruhn, B., Wipfelder, E., and Heusinger, H. (1976). Off-line
coupling of liquid chromatograph and mass spectrometer. Analytical
Chemistry 48:1270-71.
Emmett, E.A. (1973). Ultraviolet radiation as a cause of skin tumors.
CRC Critical Reviews in Toxicology 2, No. 2:211-55.
Emmett, E.A. (1975). Occupational skin cancer: a review. J. Occup.
Med. 17, No. 1:44-9.
Emmett, E.A. , Stetzer, L., and Taphorn, B. C1977). Phototoxic kerato-
conjunctivitis from coal-tar pitch volatiles. Science 198:841-2
(.Nov. 25) .
Encyclopaedia Britannica, Inc. (1969). Furnaces; Firebrick; Graphite.
Chicago, William Benton, Vol. 9, pp. 1037-41; 294-5; Vol. 10, pp. 694-5.
Encyclopaedia Britannica, Inc. (1974). Coal Processing. Macropaedia
Vol. 4. Chicago, Helen E. Benton, pp. 782-90.
Equitable Environmental Health, Inc. (1977). Mortality of aluminum
workers. Final report. Prepared for the Aluminum Association, Inc.
750 Third Ave., New York, 10017.
Everall, J.D., Hansteen, I.L., and Lawler, D.S. (1967). Chromosome
studies in pitch warts. British Journal of Dermatology 79:271-7.
Everett, M.A., and Miller, J.V. (1961). Coal tar and ultraviolet light.
II. Cumulative effects. Arch. Dermatol. 84:99-102.
Farooq, R., and Kirkbright, G.F. (1976). Detection and determination of
polynuclear aromatic hydrocarbons by luminescence spectrometry utilising
the Shpol'skii effect at 77K. Analyst 101:566-73.
-------
- 201 -
Fassel, V.A., and Kniseley, R.N. (1974). Inductively coupled plasma -
optical emission spectroscopy. Analytical Chemistry 46:1110A-1120A.
Finelli, V.N., Menden, E.E. , and Petering, H.G. (1972). Isolation of
metal-binding fractions from tobacco smoke condensate. Environmental
Science and Technology 6:740-44.
Fisher, R.E.W. (1953). Occupational skin cancer in a group of tar
workers. Arch. Ind. Hyg. Occup. Med. 7:12-18.
Foerster, H,R., and Schwartz, L. (1939). Industrial dermatitis and
melanosis due to photosensitization. Archives of Dermatology and
Syphilology 39:55-68.
Fox, M.A., and Staley, S.W. (1976). Determination of polycyclic aromatic
hydrocarbons in atmospheric particulate matter by high pressure liquid
chromatography coupled with fluorescence techniques. Analytical
Chemistry 48:992-98.
Francis, W. (1961). Coal: Its Formation and Composition. London,
Edward Arnold Publishers, Ltd., pp. 1-47.
Freedberg, I.M. (1965). Effects of local therapeutic agents upon epidermal
' macromolecular metabolism. Journal of Investigative Dermatology 45:529-38.
Freeman, R.G. (.1970) . Interaction of phototoxic compounds with cells in
tissue culture. Arch. Dermatol. 102:521-6.
Friedel, R.A., and Orchin, M. (1951). Ultraviolet Spectra of Aromatic
Compounds. New York, John Wiley and Sons, Inc.
Fujiwara, S., and Wainai, T. (1961). Nuclear magnetic resonance of tar
products. Chem. Soc. Jap. Bull. 34:881-82.
Fullerton, R.W. (1967) . Impingement baffles to reduce emissions from
coke quenching. Journal of the Air Pollution Control Association
17:807-9.
Gammage, R.B. (.1977). Proceedings of the Second ORNL Workshop on Exposure
to Polynuclear Aromatic Hydrocarbons in Coal Conversion Processes, held
at Oak Ridge Associated Universities, Oak Ridge, Tennessee, Mar. 9-11,
1977. Oak Ridge National Laboratory Publication No. CONF-770361, 135 pp.
Available from the U.S. National Technical Information Service.
Garrett, A.S. (1977). Medical surveillance. Workshop on Exposure to
Polynuclear Aromatic Hydrocarbons in Coal Conversion Processes. I.
Medical Surveillance. Oak Ridge National Laboratory, Tennessee, March 9.
Gary, J.H.. and Handwerk, G.E. (1975). Petroleum Refining. Technology and
Economics. New York, Marcel Dekker, Inc.
Gerstle, R.W. (1974). Atmospheric emissions from asphalt roofing processes.
U.S. Environmental Protection Agency Publication EPA/650/2-74-101, 160 pp. U.S.
National Technical Information Service Report No. PB-238 445.
-------
- 202 -
Ghosh, A., Ghosh, B.B., and Basu, A.K. (1974). Preliminary observations
on acute toxicity of a coal-tar mill effluent, using copepod as test
animal. Indian J. Exp. Biol. 12, No. 2:203-4.
Giger, W., and Blumer, M. (1974). Polycyclic aromatic hydrocarbons in
the environment: isolation and characterization by chromatography,
visible, ultraviolet, and mass spectrometry. Analytical Chemistry
46:1663-71.
Gmyrya, A.I., Fomicheva, L.V., and Prokopenko, V.I. (1970). (Changes in
the organ of vision and their prevention among workers in a mercury and
in a coal tar chemical industry.) Oftal'mologicheskii Zhurnal 25, No. 8:
570-73.
Goeckner, N.A., and Griest, W.H. (1977). Determination of methyl chrysenes
in a coal liquefaction product. Science of the Total Environment 8:187-93.
Gold, A. (1975). Carbon black adsorbates: separation and identification
of a carcinogen and some oxygenated polyaromatics. Analytical Chemistry
47:1469-72.
Golden, C., and Sawicki, E. (1973). Ultrasonic extraction of total particu-
late aromatic hydrocarbons (TpAH) from airborne particles at room tempera-
ture. Presented at the 165th National Meeting of the American Chemical
Society, Dallas, Texas, April 9.
Goldstein, G. (1976). Separation of polycyclic aromatic hydrocarbons by
liquid chromatography on cross-linked polycinylpyrrolidone. Journal
of Chromatography 129:61-72.
Gorbov, V.A., and Fomenko, V.N. (1962). (The hygienic evaluation of
asphalt paving as a possible source of contamination of the atmosphere
with carcinogenic substances.) Gigiena i Sanitariya No. 6i100-1.
Gorman, P.G. (1976). Control technology for asphalt roofing industry-
U.S. Environmental Protection Agency Publication EPA-600/2-76-120, 114 pp.
U.S. National Technical Information Service Report No. PB-253 415.
Gorski, T. (1959). (Experimental investigations on the carcinogenic
properties of some pitches and tars produced from Silesian pit coal.)
Medycyna Pracy 10:309-17.
Gorski, T., and Malchar, U. (1965). (Danger of carcinogenic pitch
conponents in the environment.) Gaz, Woda Tech. Sanit. 39, No. 8:
268-70.
Greenhow, E.J., and Smith, J.W. C1960). Australian J. Appl. Sci.
11, No. 1:169. (Cited in McNeil, 1966a, p. 215).
Greinke, R.A., and Lewis, I.C. (1975). Development of a gas chromatographic-
ultraviolet absorption spectrometric method for monitoring petroleum
pitch volatiles in the environment. Analytical Chemistry 47:2151-55.
Greither, A., Gisbertz, C., and Ippen, H. (1967). Teerbehandlung und Krebs.
(.Tar treatment and cancer.) Zsch. Haut-Geschl.-Krkh. 42, No. 15:631-35.
-------
- 203 -
Griest, W.H., Kubota, H., and Eatherly, W.P. (1977). Characterization of
PAH-containing fugitive emissions from a graphite production operation.
Abstract from ORNL Workshop on Exposure to Polynuclear Aromatic
Hydrocarbons in Coal Conversion, March 9-11.
Grigor'ev, Z.E. (1954). (Cancerogenic properties of semicoking tars from
Cheremkha coal.) Gigiena i Sanitariya No. 7:26-8.
Grigor'ev, Z.E. (,1959) . (Toxicity of the so-called heavy tar obtained from
Cheremkhovo coal.) Gigiena i Sanitariya 24, No. 3:33-7.
Gromiec, J.P. (1975). Health hazards associated with the aluminum
production. Master's Thesis, University of Cincinnati, 58 pp.
Gruber, M., Klein, R., and Foxx, M. (1970). Chemical standardization and
quality assurance of whole crude coal tar USP utilizing GLC procedures.
Journal of Pharmaceutical Sciences 59:830-34.
Guardascione, V., and Cagetti, D. (1962). (On a case of laryngeal cancer
manifested in a worker employed in road bituminization.) Rass. Med.
Ind. 31:114-17.
Gunter, B.J., and Ligo, R. (1976). Health Hazard Evaluation Determination
Report 75-13-265. Protecto Wrap Company, Denver, Colorado. U.S. National
Institute for Occupational Safety and Health.
Hadden, N., Baumann, F., MacDonald, F. , Munk, M., Stevenson, R., Gere, D. ,
Zamaroni, F., and Majors, R. (1971). Basic Liquid Chromatography. Walnut
Creek, California, Varian Aerograph, 237 pp.
Halbwachs, G. , and Hlawatsch, H. (1968). Photooxydation als Ursache von
Pflanzenschadigungen durch Teerdampfe. Naturwissenschaften 55, No. 2:90.
Haley, G.A. (1975). Changes in chemical composition of a Kuwait short
residue during air blowing. Analytical Chemistry 47, No. 14:2432-37.
Hammond, E.G., Selikoff, I.J., Lawther, P.L., and Seidman, H. (1976).
Inhalation of benzpyrene and cancer in man. Ann. N.Y. Acad. Sci. 271:116-24.
Hanson, W.E. (1964). Nomenclature and terms. In Hoiberg, A.J., Ed.:
Bituminous Materials: Asphalts, Tars, and Pitches, Vol I. New York,
Interscience Publishers, pp. 2-22.
Hase, A., Lin, P.H., and Kites, R.A. (1976). Analysis of complex polycyclic
aromatic hydrocarbon mixtures by computerized GC-MS. In Freudenthal, R. ,
and Jones, P.W.: Carcinogenesis - A Comprehensive Survey, Vol. 1. New York,
, Raven Press, pp. 435-42.
Hawthorne and Thorngate (1977). Preliminary results from second-derivative
absorption spectrometry applied to monitoring of PNA. In Gammage, R.B.
k (1977), pp. 95-103.
Henry, S.A. (1947). Occupational cutaneous cancer attributable to certain
chemicals in industry. British Medical Bulletin 4:389-401.
-------
- 204 -
Henry, S.A., Kennaway, N.M., and Kennaway, E.L. (1931). The incidence of
cancer of the bladder and prostate in certain occupations. Journal of
Hygiene 31:125-37.
Hervin, R.L., and Emmett, E.A. (1976a). Western Roofing Company, Sellers
and Marquis Roofing Company, A.J. Shirk Roofing Company, and the Quality
Roofing Company; A Joint Venture, Kansas City, Missouri 64130. NIOSH
Health Hazard Evaluation Determination Report No. 75-194-324, Cincinnati,
Ohio.
Hervin, R.L., and Emmett, E.A. (1976b). Sellers and Marquis Roofing Company,
A.J. Shirk Roofing Company, Western Roofing Company, and the Quality
Roofing Company; A Joint Venture, Kansas City, Missouri 64130. NIOSH
Health Hazard Evaluation Determination Report No. 75-102-304, Cincinnati,
Ohio.
Hilfrich, J., and Mohr, U. (1972). Vergleichende Untersuchungen zur
carcinogenen Wirkung des herkb'mmlichen Steinkohlenteers and einer neunen
synthestischen Teermischung. Arch. Derm. Forsch. 242:176-8.
Hirohata, T., Masuda, Y., Horie, A., and Kuratsune, M. (1973). Carcinogenicity
of tar-containing skin drugs: animal experiment and chemical analysis.
Gann 64:323-30.
Hirsch, D.E., Hopkins, R.L., Coleman, H.J., Cotton, P.O., and Thompson,
C.-J. (1972) . Separation of high-boiling petroleum distillates using
gradient elution through dual-packed (silica gel-alumina gel) adsorption
columns. Analytical Chemistry 44:915.
Hittle, D.C., and Stukel, J.J. (1976). Particle size distribution and
chemical composition of coal-tar fumes. American Industrial Hygiene
Association Journal 37, No. 4:199-204.
Hodgson, G.A., and Whiteley, H.J. (1970). Personal susceptibility to
pitch. Brit. J. Industr. Med. 27:160-66.
Hoffman, D., and Wynder, E.L. (1968). Chemical analysis and carcinogenic
bioassays of organic particulate pollutants. In Stern, A., Ed.: Air
Pollution, Vol. 2. New York, Academic Press, pp. 187-247.
Hoiberg, A.J., Ed. (1965a). Bituminous materials. In Encyclopedia
Polymer Science and Technology, Vol. 2. New York, Interscience
Publishers, pp. 402-37.
Hoiberg, A.J., Ed. (1965b}. Bituminous Materials: Asphalts, Tars, and
Pitches, Vol. II. Asphalts, Part 1. New York, Interscience Publishers,
698 pp.
Hoiberg, A.J., Ed. (1966). Bituminous Materials: Asphalts, Tars, and
Pitches, Vol. III. Coal Tars and Pitches. New York, Interscience
Publishers, 585 pp.
Hoiberg, A.J., Corbett, L.W., and Lewis, R.B. (1963). Asphalt. In Kirk-
Othmer Encyclopedia of Chemical Technology, 2nd ed., Vol. 2. New York,
Interscience Publishers, pp. 762-801.
-------
- 205 -
Hoiberg, A.J., and Garris, W.E., Jr. (1944). Analytical fractionation
of asphalts. Ind. Eng. Chem., Anal. Ed. 16:294.
Horton, A.W., Denman, D.T., and Trosset, R.P. (1957). Carcinogenesis
of the skin. II. The accelerating properties of aliphatic and related
hydrocarbons. Cancer Research 17:758-66.
Horton, A.W., Tye, R., and Stemmer, K.L. (1963). Experimental carcinogenesis
of the lung. Inhalation of gaseous formaldehyde or an aerosol of coal
tar by C3H mice. J. Natl. Cancer Inst. 30:31-40.
Hueper, W.C. (1963). Occupational cancers of the respiratory organs.
In Banyai, A.L., and Gordon, B.L., Eds.: Advances in Cardiopulmonary
Diseases. Vol. 1. Selected Lectures from the 1961 Series of the
American College of Chest Physicians. Chicago, II., Year Book Medical
Publishers, pp. 147-77.
Hueper, W.C. (1965) . Blown asphalt not carcinogenic. American Industrial
Hygiene Association Journal 26:95.
Hueper, W.C., Kotin, P., Tabor, E.G., Payne, W.W., Falk, H., and Sawicki, E.
(1962). Carcinogenic bioassays on air pollutants. Arch. Pathol. 74:89-116.
Hueper, W.C., and Payne, W.W. (1960). Carcinogenic studies on petroleum
asphalt, cooling oil, and coal tar. AMA Arch. Pathol. 70:372-84.
Hunt, D.C., Wild, P.J., and Crosby, N.T. (1977). Phthalimidopropylsilane —
A new chemically bonded stationary phase for the determination of
polynuclear aromatic hydrocarbons by high-pressure liquid chromatography.
Journal of Chromatography 130:320-23.
Hurtubise, R.J., Schabron, J.F., Feaster, J.D., Therkildse, D.H., and
Poulson, R.E. (19771. Fluorescence characterization and identification
of polynuclear aromatic hydrocarbons in shale oil. Analytica Chimica
Acta 89:377-82.
International Agency for Research on Cancer (1973). IARC Monographs on
the Evaluation of Carcinogenic Risk of Chemicals to Man. Vol. 3. Certain
Polycyclic Aromatic Hydrocarbons and Heterocyclic Compounds. Lyon, France,
International Agency for Research on Cancer, 271 pp.
International Agency for Research on Cancer (1976). IARC Monographs on
the Evaluation of Carcinogenic Risk of Chemicals to Man. Vol. 11. Cadmium,
Nickel, Some Epoxides, Miscellaneous Industrial Chemicals and General
Considerations on Volatile Anaesthetics. Lyon, France, International
Agency for Research on Cancer, 306 pp.
Ives, N.F., and Giuffrida, L. (1972). Food additives. Liquid chromatography
of polycyclic aromatic hydrocarbons. Journal of the Association of
Official Analytical Chemists 55:757-61.
Jackson, J.O. , Warner, P.O., and Mooney, T.F., Jr. ,(1974). Profiles of
benzo(a)pyrene and coal tar pitch volatiles at and in the immediate
vicinity of a coke oven battery. American Industrial Hygiene Association
Journal 35:276-81.
-------
- 206 -
Janini, G.M., Johnston, K., and Zielinski, W.L., Jr. (1975). Use of a
nematic liquid crystal for gas-liquid chromatographic separation of
polyaromatic hydrocarbons. Analytical Chemistry 47:670-74.
Janini, G.M., Muschik, G.M., and Zielinski, W.L., Jr. (1976). N,N'-
Bis(£-butoxybenzylidene)-a,al-bi-p_-toluidine: Thermally stable liquid
crystal for unique gas-liquid chromatography separations of polycyclic
aromatic hydrocarbons. Analytical Chemistry 48:809-13.
Jewell, D.M., Albaugh, E.W., Davis, B.E., and Ruberto, R.G. (1974).
Integration of chromatographic and spectroscopic techniques for the
characterization of residual oils. Industrial and Engineering Chemistry
13:278-82.
Jewell, D.M., Ruberto, R.G., and Davis, B.E. C1972a}. Systematic approach
to the study of aromatic hydrocarbons in heavy distillates and residues
by elution adsorption chromatography. Analytical Chemistry 44:2318-21.
Jewell, D.M., Weber, J.H., Hunger, J.W., Plancher, H., and Latham, D.R.
(1972b). Ion-exchange, coordination, and adsorption chromatographic
separation of heavy-end petroleum distillates. Analytical Chemistry
44:1391-95.
Jobson, A., Cook, F.D., and Westlake, D.W.S. (19721. Microbial utilization
of crude oil. Appl. Microbiol. 23:1082-89.
Jones, H.R. (1973). Pollution Control in the Petroleum Industry. Park
Ridge, New Jersey, Noyes Data Corp.
Jones, P.R. , and Yang, S.K. (1975). A liquid chromatograph/mass spectrometer
interface. Analytical Chemistry 47:1000-3.
Jones, P.W. (1977). Criteria for sampling airborne PNAs. In Gammage, R.B.
(1977) , pp. 61-2.
Just, J., Maziarka, S., Misiakewicz, Z., and Wyszynska, H. (1971). (Auto-
mobiles and the type of road surface as possible sources of air pollution
with cancerogenic substances and lead.) Roczn. Zak. Hig. (Warsaw). 22,
No. 5:545-51. (From Excerpta Medica, Section 46: Environmental Health
and Pollution Control 2:3757, 1972.)
Kaidbey, K.H., and Kligman, A.M. (1974a). A human model of coal tar acne.
Arch. Dermatol. 109:212-15.
Kaidbey, K.H., and Kligman, A.M. (1974b). Topical photosensitizers.
Influence of vehicles on penetration. Arch. Dermatol. 110:868-70.
Kaidbey, K.H., and Kligman, A.M. (1975). Further studies of photoaugmenta-
tion in humans: phototoxic reactions. Journal of Investigative Derma-
tology 65:472-75.
Kaidbey, K.H., and Kligman, A.M. (1977). Clinical and histological study
of coal tar phototoxicity in humans. Archives of Dermatology 113:592-95.
-------
- 207 -
Kandahl, P.S. (1974). Asphalt emulsions for cleaner air and conservation
of energy. Publ. Wks. 105, No. 7:76. (From Excerpta Medica, Section 46:
Environmental Health and Pollution Control 8:1349, 1975.)
Kandus, J., Masek, V., and Jach, Z. (1972). (Determination of the
3,4-benzopyrene content in the clothing and underwear of workers in
a pitch processing plant.) Zbl. Arbeitsmed. 22:138-41.
Kapitul'skii, V.B., Potapova, A.N., Filatova, A.S., Kuz'minykh, A.I., and
Khalemin, Y.A. (1971). (Sanitary working conditions in the blast furnace
industry in connection with the addition of pitch to refractory materials.)
Gig. Tr. Prof. Zabol. 15, No. 10:41-43.
Karasek, F.W. , Denney, D.W., Chan, K.W., and Clement, R.E. (1978). Analysis
of complex organic mixtures on airborne particulate matter. Analytical
Chemistry 50:82-87.
Karr, C. , Brown, P.M., Estep, P.A., and Humphrey, G.P. (1958). Identification
and determination of low-boiling phenols in low temperature coal tar.
Analytical Chemistry 30:1413-16.
Karr, C., Childers, E.E., Warner, W.C., and Estep, P.E. (1964). Analysis
of aromatic hydrocarbons from pitch oils by liquid chromatography on gas
chromatography analog. Anal. Chem. 36:2105-8.
Karr, C., Estep, P.A., and Hirst, L.L. (1970). Countercurrent distribution
of high-boiling phenols from a low-temperature coal tar. Analytical
Chemistry 32:463-75.
Karr, C., Estep, P.A., and Papa, A.J. (1959). Infrared spectra-structural
correlations of quinolines. Journal of the American Chemical Society
81:152-56.
Katz, M./ and Monkman, J.L. (1964). The organic fraction of particulate
pollution including polycyclic hydrocarbons. Occupational Health
Review 16:3-16.
Kawahara, F.K. Q.9691. Identification and differentiation of heavy residual
oil and asphalt pollutants in surface waters by comparative ratios of
infrared absorbances. Environmental Science and Technology 3:150-53.
Keefer, L.K., Wallcaye, L. , Loo, J., and Peterson, R.S. (1971). Analysis of
mixtures of isomeric polynuclear hydrocarbons by nuclear magnetic resonance
spectrometry. Methylated derivatives of anthracene, benz[a]anthracene ,
benzojcjphenanthrene, and pyrene. Analytical Chemistry 43:1411-16.
Kernkamp, H.C.H. (1964). Coal-tar poisoning and mercury poisoning. In
Dunne, H.W., Ed.:. Diseases of Swine, 2nd ed. Ames, Iowa University
Press, pp. 575-77.
Kertesz-Saringer, M., Meszaros, E., and Varkonyi, T. (1971). On the size
distribution of benzo(alpyrene containing particles"in urban air.
Atmospheric Environment 5:429-31.
-------
- 208 -
Ketcham, N.H., and Norton, R.W. (I960). The hazards to health in the
hydrogenation of coal. III. The industrial hygiene studies. Archives
of Environmental Health 1:194-207.
Khosa, D. , and Chandrasekhar, K. (1972). Effect of copper acetate and
asphalt on gonadal activities and the correlated changes in the preoptic
nucleus of two genera of teleostean fish, Clarias batrachus and
Ophicephalus punctatus. Proc. Indian Acad. Sci., Sect. B. 76, No. 6:
229-39.
Kireeva, I.S. C1968). Carcinogenic properties of coal-tar pitch and
petroleum asphalts used as binders for coal briquettes. Hygiene and
Sanitation 33, No. 4-6:180-86. Translation of Gigiena i Sanitariya
33, No. 5:35-40.
Kireeva, I.S., and Yanysheva, N.Ya. (1970). (Pollution of atmospheric
air by carcinogenic polycyclic aromatic hydrocarbons from a petroleum
refinery.) Gig. Naselen. Mest. Resp. Mezhvedom. Sb. No. 9:113-17.
Kireeva, I.S., and Yanysheva, N.Y. (1972). (Efficacy of preventive
measures against the carcinogenic hazards in coal briquette production.)
Gigiena i Sanitariya 37, No. 2:10-14.
Klein, D.H. (1972). Mercury and other metals in urban soils. Environmental
Science and Technology 6, No. 6:560-62.
Kleinschmidt, L.R. (19551. Chromatographic method for the fractionation
of asphalt into distinctive groups of components. J, Res, Natl. Bur.
Std. 54:163.
Klimisch, H.-J. (1973a). Separation of polycyclic aromatic hydrocarbons
by high-pressure liquid chromatography. Selective separation system
for the quantitative determination of isomeric benzpyrenes and of
coronene. Journal of Chromatography 83:11-14.
Klimisch, H.-J. t!973b). Determination of polycyclic aromatic hydrocarbons.
Separation of benzpyrene isomers by high-pressure liquid chromatography
on cellulose acetate columns. Analytical Chemistry 45:1960-62.
Klimisch, H.-J., and Fox, K. (1976). Zur Trennung N-heteropolyzyklischer
aromatischer Kohlenwasserstoffe von polyzyklischen aromatischen
Kohlenwasserstoffen. Abtrennung durch Komplexchromatographie. Journal
of Chromatography 120:482-84.
Knosel, D. , and Rademacher, B. (1964). (Injury to plants by effluents
from plants for mixing bituminous aggregates.) Z. Pflanzenkrankh.
Pflanzenschutz 71, No. 5:311-16.
Knotnerus, J. (1967). Constitution of asphaltic bitumen. Characterization
of bitumens by a combination of pyrolysis, hydrogenation, and gas-liquid
chromatography. I and EC Product Research and Development 6:43-52.
Knowles, E.G., McCoy, F.C., Weetman, B., and Eckert, G.W. (1958). Relation
of asphalt composition to its durability in service. American Chemical
Society, Division of Petroleum Chemistry, Preprints 3, No. 2:A29-A37.
-------
- 209 -
Kochloefl, K., Schneider, P., Rericha, R., and Bazant, V. (1963). Composition
of the (West-Bohemian) brown-coal tar fraction, b.p. 220-80°. II. Branched
paraffinic and cycloparaffinic hydrocarbons. Collection Czech. Chem.
Commun. 28, No. 12:3362-81. (From Chemical Abstracts 60:13063g, 1964.)
Kolomaznik, L., Zdrazil, J., and Picha, F. (1963). (Incidence of benign
neoplasms, and precancerous and cancerous conditions in the respiratory
passages of foundry workers, laboring in an atmosphere with a high content
of 3,4-benzpyrene.) Cesk. Otolaryngol. 12, No. 1:1-11.
Konstantinov, V.G., Filatova, A.S., Kuz'minykh, A.I., and Ustyuzhanina, Z.V.
(1973). (Hygienic assessment of the use of petroleum pitchbound anode
mass in electrolytic production of aluminum.) Gigiena i Sanitariya
38, No. 3:27-30.
Konstantinov, V.G., and Kuz'minykh. A.I. (1971). Tarry substances and
3,4-benzpyrene in the air of electrolytic shops of aluminum works and
their carcinogenic significance. Hygiene and Sanitation 36, No. 1-3:
368-74. English translation of Gigiena i Sanitariya 36, No. 3:39-42.
Koppenaal, D.W., and Manahan, S.E. (1976). Hazardous chemicals from
coal conversion processes? Environmental Science and Technology 10:
' 1104-7 (Nov.).
Kovalenko, L.M. (.1965) . (On inflammatory epithelial proliferations of
the preputial glands under experimental conditions.) Arkh. Patol. 27,
No. 9:69-71.
Kratky, Z. (1968). CElimination of effluents from asphalt oxidation.)
' Ropa Uhlie 10, No. 9:472-6.
Krchma, L.C., and Gagle, D.W. (1974). A U.S.A. history of asphalt refined
from crude oil and its distribution. Proceedings of the Association of
Asphalt Paving Technologists 43A:25-88.
Kronberger, W., and Halbwachs, G. (1975). (Effect of hot mix asphalt
plants on vegetation with special regard to vapors from asphaltic
bitumen.) Eur. J. For. Pathol. 5, No. 5:267-74.
Kudrin, L.V., Ashmarina, N.P., Strizhak, E.K., and Boldina, Z.N. (1968).
(Sanitary-hygienic evaluation of the effect of water proofing substances
used in lumbering operations Clog floating) on the quality of the
water in reservoirs (pitch-tar varnish).) In Shitskova, A.P., Ed.:
Vop. Gig. Vody Sanit. Okhr. Vodoemov. Moscow, USSR, Mostk. Nauch.-Issled.
Inst. Gig., pp. 127-32.
Kukreja, V.P., and Bove, J.L. (1976). An enrichment method for polycyclic
aromatic hydrocarbons (PAH's) collected on glass fiber filters using
hydrofluoric acid. J. Environ. Sci. Health All, No. 8-9:517-24.
Lambers, G.M., and Van Ulsen, F.W. (1973). Ovoid coal poisoning in
piglets. Tijdschr. Diergeneesk. 98, No. 14:681-82.
Lannoye, R.A., and Greinke, R.A. (1974). An improved fluorometric method
of analysis for benzo(a)pyrene in airborne particulates. Am. Ind. Hyg.
Assoc. J. 35:755-65.
-------
- 210 -
Lao, R.C., Thomas, R.S., and Monkman, J.L. (1976). Computerized gas-
chromatographic mass spectrometry analysis of environmental samples
for polycyclic aromatic hydrocarbons. A cost effect approach. In
Abstracts of the First ORNL Workshop on Polycyclic Aromatic Hydrocarbons:
Characterization and Measurement with a View Toward Personnel Protection.
Oak Ridge National Laboratory Publication No. ORNL/TM-5598, pp. 17-30.
Oak Ridge, Tennessee.
Lao, R.C., Thomas, R.S., Oja, H., and Dubois, L. (1973). Application of
a gas chromatograph-mass spectrometer-data processor combination to the
analysis of the polycyclic aromatic hydrocarbon content of airborne
pollutants. Analytical Chemistry 45:908-15.
Larsen, L.B. (1973). Industrial hygiene survey at the Intalco Aluminum
Company, Ferndale, Washington. National Institute for Occupational
Safety and Health, Western Area Occupational Health Laboratory, Salt
Lake City, Utah.
Lauer, G.G. (1974). Coal tar and derivatives. In Considine, D.M. , Ed.:
Chemical and Process Technology Encyclopedia. New York, McGraw-Hill,
pp. 297-302.
Lawther, P.J., Commins, B.T., and Waller, R.E. C1965). A study of the
concentrations of polycyclic aromatic hydrocarbons in gas works retort
houses. British Journal of Industrial Medicine 22:13-20.
Lee, M.L., Novotny, M., and Bartle, K.D. (1976). Gas chromatography/mass
spectrometric and nuclear magnetic resonance spectrometric studies of
carcinogenic polynuclear aromatic hydrocarbons in tobacco and marijuana
smoke condensates. Analytical Chemistry 48:405-16.
Leibnitz, E., Naumann, K., and Killer, C.M. (1958). The bases of brown-
coal tar. IV. The paper chromatography of brown-coal-tar bases.
Chem. Tech. (Berlin) 10:82-84.
Lett, R.G., Schmidt, C.E., DeSantis, R.R., and Sharky, A.G., Jr. (1977).
Screening for hazardous elements and compounds in process streams of
the 3j ton per day synthoil process development unit. Pittsburgh
Energy Research Center Publication PERC/RI-77/12. Available from the
U.S. National Technical Information Service.
Lev, N.A., Volkova, F.R., Shekhtman, A.M., Belopashentseva, V.V., and
Alekseeva, A.A. (1966). (Clinical course of coal tar poisoning.)
Vrach Delo 11:83-5.
Lewis, R.B. (1965). Commercial aspects of asphalts. In Hoiberg, A.J., Ed.
Bituminous-Materials: Asphalts, Tars, and Pitches. Vol. II. Asphalts,
Part 1. New York, Interscience Publishers, pp. 123-49.
Libke, K.G., and Davis, J.W. (1967). Hepatic necrosis in swine caused by
feeding clay pigeon targets. Journal of the American Veterinary Medical
Association 151:426-9.
Libke, K.G., and Davis, J.W. (1968). Toxicity of clay pigeon targets in
goats. American Journal of Veterinary Research 29:2383-6.
-------
- 211 -
Liggett, L.M. (1964). Carbon (baked, and graphitized, manufacture). In
Kirk-Othmer Encyclopedia of Chemical Technology, 2nd ed., Vol. 4. New
York, Interscience Publishers, pp. 158-202.
Lijinsky, W., Domsky, I., Mason, G., Ramahi, H.Y., and Safavi, T. (1963).
The chromatographic determination of trace amounts of polynuclear
hydrocarbons in petrolatum, mineral oil, and coal tar. Analytical
Chemistry 35:952-56.
Linnik, A.B. (.1970) . (The carcinogenic effect of Lokakorten-tar-ointment
under experimental conditions.) Vestn. Dermatol. Venerol. 44, No. 12:
32-6.
Lloyd, J.W. (.1971) . Long-term mortality study of steelworkers. V.
Respiratory cancer in coke plant workers. Journal of Occupational
Medicine 13:53-68.
Macak, J., and Rehak, J. (1962). Composition of phenols from a brown-
• coal tar temperature tar. Brennst.-Chem. 48:80-6.
MacEwen, J.D. (1976). Studies on the carcinogenesis of coal tar aerosols.
B. Inhalation. In Industrial Health Foundation, Inc.: Proceedings of
the Symposium on Particulate Polycyclic Organic Matter, Pittsburgh, Pa.,
April 29-30, 1975, pp. 29-53.
McFadden, W.H., Schwartz, H.L., and Evans, S. (1976). Direct analysis
of liquid chromatographic effluents. Journal of Chromatography 122:
389-96.
McGannon, H.E., Ed. (1971). The Making, Shaping and Treating of Steel,
9th ed. Pittsburg, Pa., Herbig and Held.
McKay, J.F., and Latham, D.R. (1972). Fluorescence spectrometry in the
characterization of high-boiling petroleum distillates. Analytical
Chemistry 44:2132-37.
McKay, J.F., and Latham, D.R. (19731. Polyaromatic hydrocarbons in
high-boiling petroleum distillates. Analytical Chemistry 45:1050-55.
McKay, J.F., Weber, J.H., and Latham, D.R. (1976). Characterization of
nitrogen bases in high-boiling petroleum distillates. Analytical
Chemistry 48:891-98.
McLafferty, F.W. (1973). Interpretation of Mass Spectra. 2nd Ed.
Reading, Massachusetts, W.A. Benjamin, Inc.
McLafferty, F.W., Knutti, R., Venkataraghavan, R., Arpino, P.J. , and
Dawkins, B.C. (1975). Continuous mass spectrometric monitoring of a
liquid chromatograph with subnanogram sensitivity using an on-line
computer. Analytical Chemistry 47:1503-5.
Maclean, C.W. (1969). Observations on coal tar poisoning in pigs.
Veterinary Record 84:594-98.
-------
- 212 -
McNeil, D. (1966a). Coal Carbonization Products. New York, Pergamon^
Press, 159 pp.
McNeil, D. (1966b). The physical properties and chemical structure of
coal tar pitch. In Hoiberg, A.J., Ed.: Bituminous Materials:
Asphalts, Tars, and Pitches. Vol. III. Coal Tars and Pitches.
New York, Interscience Publishers, pp. 139-227.
McNeil, D. C1969). Tar and pitch. In Kirk-Othmer Encyclopedia of
Chemical Technology, 2nd ed., Vol. 19. New York, Interscience
Publishers, pp. 653-82.
Maher, T.P. (1968). The liquid products from the low temperature
carbonization of two bituminous coals. Fuel (London) 47:359-72.
Mallison, H. C19501, Bit., Teere, Asph. Peche 1:313. (Cited in McNeil,
1966a, p. 215.)
Mantell, C.L., Ed. (1975). Petroleum. In Solid Wastes: Origin,
Collection, Processing, and Disposal. New York, Wiley Interscience
Publishers, pp. 924-26.
Marsico, A.P., and Eaglstein, W.H. (1973). Role of long-wave ultraviolet
light in Goeckerman treatment. Archives of Dermatology 108:48-49.
Masek, V. (1964). (Determination of 3,4-benzopyrene in the high temperature
tars of bituminous coal.) Koks i Khim. 12:40-43.
Masek, V. (1970) . The use of silver membrane filters in sampling for coal
tar pitch volatiles in coke oven plants. American Industrial Hygiene
Association Journal 31, No. 5:641-44.
Masek, V. (19711. Benzo(a)pyrene in the workplace atmosphere of coal
and pitch coking plants. Journal of Occupational Medicine 13:193-98.
Masek, V. (.1972) . (New data on the properties of airborne dust from coking
plants. IV. Installations for the distillation of bituminous coal tar.)
Zentralbl. Arbeitsmed. 22:332-7.
Masek, V., Jach, Z., and Kandus, J. (1972). Content of 3,4-benzo(a)pyrene
in the working clothes and underwear of workers at a pitch coking plant.
Journal of Occupational Medicine 14:548-51.
Massey, M.J. C19771. A basic orientation to coal conversion processes.
Presented at the Workshop on Exposure to Polynuclear Aromatic Hydrocarbons
in Coal Conversion Processes. I. Medical Surveillance. Oak Ridge
National Laboratory, Oak Ridge, Tennessee, March 9.
May, W.E., Wasik, S.P., and Freeman, D.H. (1978). Determination of
the solubility behavior of some polycyclic aromatic hydrocarbons
in water. Analytical Chemistry 50, No. 7:997-1000.
Mazumdar, S., Redmond, C., Sollecito, W., and Sussman, N. (1975). An
epidemiological study of exposure to coal tar pitch volatiles among
coke oven workers. Journal of the Air Pollution Control Association
25, No. 4:382-89.
-------
- 213 -
Mendenhall, R.L. (1976). Process for recycling asphalt-aggregate compositions.
U.S. Patent 4,000,000, Dec. 28, Appl. 488,518, July 15, 1974, 6 pp.
Mertens, E.W., and Borgfeldt, M.J. (1965). Cationic asphalt emulsions.
In Hoiberg, A.J., Ed.: Bituminous Materials: Asphalts, Tars, and Pitches.
Vol. II. Asphalts. Part 1. New York, Interscience Publishers, pp. 359-90.
Mestitzova, M. (1961). (Chronic exposure of inbred mice to tar vapors.)
Pracovni Lekarstvi 13:55-62.
Mikheeva, A.P. (1967) . (The functional status of the stomach in workers
engaged in the production of pitch coke.) Gig. Tr. Prof. Zabol. 11,
No. 2:24-9.
Miles, T.K. (1977). Asphalt and asphaltite. Petroleum by-product. McGraw-
Hill Encyclopedia of Science and Technology, Vol. 1. New York, McGraw-
Hill, Inc., p. 638.
Montesano, R. , and Tomatis, L. (1977). Legislation concerning chemical
carcinogens in several industrialized countries. Cancer Research 37:
310-16.
Moret, C. (1912). Ocular lesions produced by pitch. Ophthalmology 8:381.
Morgan, D.D., Warshawsky, D. , and Atkinson, T. (1977). The relationship
between carcinogenic activities of polycyclic aromatic hydrocarbons and
their singlet, triplet, and singlet-triplet splitting energies and
phosphorescence lifetimes. Photochemistry and Photobiology 25:31-8.
Mutschler, P.H. (1975). Impact of changing technology on the demand for
metallurgical coal and coke produced in the United States to 1985.
U.S. Bureau of Mines, Information Circular 8677, 26 pp.
Myers, M.E., Jr., Stollstelmer, J. , and Wims, A.M. (1975). Determination
of hydrocarbon-type distribution and hydrogen/carbon ratio of gasolines
by nuclear magnetic resonance spectrometry. Analytical Chemistry 47:
2010-15.
National Research Council, Committee on Biologic Effects of Atmospheric
Pollutants (1972). Particulate Polycyclic Organic Matter. Washington,
D.C., National Academy of Sciences, 361 pp.
National Research Council, Committee on Biologic Effects of Atmospheric
Pollutants (1974). Vanadium. Washington, D.C., National Academy of
Sciences, 117 pp.
National Research Council, Committee on Medical and Biologic Effects
of Environmental Pollutants (1975). Nickel. Washington, D.C.,
National Academy of Sciences, 277 pp.
National Safety Council (1965). Asphalt. National Safety Council
Data Sheet 215 (revised), 6 pp. - -
National Safety Council (1974). Accident Prevention Manual for Industrial
Operations, 7th ed. Chicago, Illinois, National Safety Council.
-------
- 214 -
Natusch, D.F.S., and Wallace, J.R. (1974). Urban aerosol toxicity: the
influence of particle size. Science 186:695-99.
Nelson, W.L. (1976). Process costimating. Oil and Gas Jounal 74, No. 9:120.
Neukomm, S., Vu Due, T., and Barblan, C. (1975). (Comparison of levels
of 14 polycyclic aromatic hydrocarbons in sedimented dust and suspended
air particles along asphalted and cemented highway stretches between
Lausanne and Geneva.) Soz. Praeventivmed. 20, No. 2:65-8.
Qbermayer, M.E., and Becker, S.W. (1935). A study of crude coal tar and
allied substances. Preliminary report. Archives of Dermatology and
Syphilology 31:796-810.
O'Connor, R.B. (1971). Improving the environmental health of coke oven
workers. Journal of Occupational Medicine 13:83-5.
O'Donnell, G. (1951). Anal. Chem. 23:894. (Cited in Altgelt and Gouw,
1975, p. 77.)
Oglesby, C.H. (1975). Highway Engineering, 3rd ed. New York, John Wiley
and Sons.
Oil, Chemical and Atomic Workers International Union (1977). Carbon
black, graphite and calcined coke. Similar industries, similar
hazards. Lifelines OCAW Health and Safety News 4, No. 4:1-3.
Oil, Paint, and Drug Chemical Buyers Directory (1975-76). 63rd Annual Ed.
New York, Schnell Publishing Co., Inc., 1616 pp.
Okubo, T., and Tsuchiya, K., (1974). (An epidemiological study on the
cancer mortality in various industries in Japan.) Jap. J. Ind. Health
16, No. 5:438-52.
Oliver, T. (1908). Tar and asphalt workers' epithelioma and chimney-sweeps'
cancer. British Medical Journal (Aug 22) , pp. 493-94.
Orchin, M. , and Jaffe, H. (1962). Theory and Application of Ultraviolet
Spectroscopy. New York, John Wiley and Sons, Inc.
Pekker, R.I. (1967). (The state of the oral cavity in workers exposed to
coal tar and pitch.) Stomatologiia (Mosk) 46, No. 6:35-9.
Perov, O.V. (1969) . The migration of hydrocarbons from the heavy fraction
of coal tar in soil. Hygiene and Sanitation 34, No. 7-9:239-42.
English translation of Gigiena i Sanitariya 34, No. 8:77-9, 1969.
Petersen, J.C., Harbour, F.A. , and Dorrence, S.M. (1975). Identification
of dicarboxylic anhydrides in oxidized asphalts. Analytical Chemistry
47:107-11.
Petersen, J.C., Barbour, R.V., Dorrence, S.M., Barbour, F.A., and Helm, R.V.
(1971). Molecular interactions of asphalt. Tentative identification
of 2-quinolones in asphalt and their interaction with carboxylic acids
present. Analytical Chemistry 43:1491-96.
-------
- 215 -
Phelan, P.P., and Rhodes, E.O. (1966). Road tars and tar paving. In
Hoiberg, A.J., Ed.: Bituminous Materials: Asphalts, Tars, and Pitches.
Vol. III. Coal Tar and Pitches. New York, Interscience Publishers,
pp. 411-531.
Pierce, R.C., and Katz, M. (1975). Determination of atmospheric isomeric
polycyclic arenes by thin-layer chromatography and fluorescence
spectrophotometry. Analytical Chemistry 47:1743-48.
Pit and Quarry (1972). Pollution control. Manufacturers reports. Asphalt
plants. Iowa Manufacturing Co. 65, No. 3:91-3.
Popl, M., Fahnrich, J., and Stejskal, M. (1976). Adsorption effect in
GPC separation of polycyclic aromatic hydrocarbons. Journal of
Chromatographic Science 14:537-40.
Popl, M., Stejskal, M., and Mostecky, J. (1975). Determination of
polycyclic aromatic hydrocarbons in white petroleum products. Analytical
Chemistry 47:1947-50.
Pott, P. (1775). Cancer scroti. In Chirugical Observations. London,
Hawes, Clark and Collings, p. 63.
Predicasts (C. Diaz-Balart, Editor) (1976). Annual Cumulative Edition,
Issue 64. Predicasts, Inc., Cleveland, Ohio; S.A. Wolpert, Publisher.
Puzinauskas, V.P., and Corbett, L.W. (1975). Report on emissions from
asphalt hot mixes. Paper presented at the American Chemical Society,
Division of Petroleum Chemistry, Inc. Meeting, Chicago, Illinois, August.
Asphalt Institute Publication No. RR-75-1A, 20 pp. College Park,
Maryland, Asphalt Institute.
Radding, S.B. , Mill, T., Gould, C.W., Liu, D.H., Johnson, H.L., Bomberger,
D.C., and Fojo, C.V. (1976). The environmental fate of selected
polynuclear aromatic hydrocarbons. U.S. Environmental Protection
Agency Publication No. EPA 560/5-75-009, 122 pp. Available from the U.S.
National Technical Information Service.
Rao, H.S., Murty, G.S., and Lahiri, A. (.I960) . The infrared and high
resolution nuclear magnetic resonance spectrum of coal tar pitch. Fuel
(London) 39:263-66.
Redmond, C.K., Ciocco, A., Lloyd, J.W., and Rush, H.W. (1972). Long-term
mortality. VT. Mortality from malignant neoplasms among coke oven
workers. J. Occup. Med. 14, No. 8:621-29.
Eeerink, H. (.1973) . Size and shape of asphaltene particles in relationship
to high-temperature viscosity. Ind. Eng. Chem. Prod. Res. Develop. 12,
No. 1:82-8.
Reerink, H., and Lijzenga, J. (1973). Molecular weight distributions of
Kuwait asphaltenes as determined by ultracentrifugation. Relation with
viscosity of solutions. Journal of the Institute of Petroleum 59,
No. 569:211-22.
-------
- 216 -
Retcofsky, H.L., Schweighardt, F.K., and Hough, M. (1977). Determination
of aromaticities of coal derivatives by nuclear magnetic resonance
spectrometry and the Brown-Ladner equation. Analytical Chemistry 49,
No. 4:585-88.
Richards, R.T. , Donovan, D.T., and Hall, J.R. (1967). A preliminary
report on the use of silver metal membrane filters in sampling for
coal tar pitch volatiles. American Industrial Hygiene Association
Journal 28:590-94.
Rizvi, S.S.H., and Vahrman', M. (1971). Separation and characterization
of total hydrocarbons from low temperature coal-tars. Pak. J. Sci.
Ind. Res. 14, No. 1-2:147-9.
Roach, S.A. (1973). Sampling air for particulates in the industrial
environment - its evaluation and control. U.S. National Institute for
Occupational Safety and Health, Cincinnati, Ohio, pp. 139-53. (Cited
in U.S. National Institute for Occupational Safety and Health, 1977a,
p. 106.)
Roads and Streets (1975). Asphalt producers — the biggest. 118:137.
Rondia, D. (1965). Sur la volatilite des hydrocarbures polycycliques.
Int. J. Mr Water Poll. 9:113-21.
Rook, A.J., Gresham, G.A., and Davis, R.A. (1956). Squamous epithelioma
possibly induced by the therapeutic application of tar. British
Journal of Cancer 10:17-23.
Rosenberg, D.G., Lofy, R.J., Cruse, H., Weisberg, E., and Beutler, B. (1976).
Assessment of hazardous waste practices in the petroleum refining industry.
U.S. Environmental Protection Agency Publication'No. SW-129C, 369 pp. U.S.
National Technical Information Service Report PB-259 097, 369 pp.
Ross, P. (1948). Occupational skin lesions due to pitch and tar. British
Medical Journal 2:369-74.
Rossini, F.D., and Mair, B.J. (1951). Composition of petroleum. In Wilson,
R.E., Symposium Chairman: Progress in Petroleum Technology. A symposium
sponsored by the Division of Petroleum Chemistry at the Diamond Jubilee
Meeting of the American Chemical Society, New York, September 3-7.
Washington, D.C., American Chemical Society, Advances in Chemistry
Series 93, pp. 334-52.
Rossini, F.D., and Mair, B.J. (1959). The work of the American Petroleum
Institute Research Project 6 on the composition of petroleum. In
Proc. 5th World Petroleum Congress. New York, World Petroleum
Publications, p. 223.
Rossini, F.D., Mair, B.J., and Streiff, A.J. (1953). Hydrocarbons from
Petroleum. The Fractionation, Analysis, Isolation, Purification and
Properties of Petroleum Hydrocarbons. American Chemical Society
Monograph Series. New York, Reinhold Publishing Co., 556 pp.
Rostler, F.S. (1965). Fractional composition: Analytical and functional
significance. In Hoiberg, A.J., 1965b, pp. 151-222.
-------
- 217 -
Hostler, F.S., and Sternberg, H.W. (1949). Compounding rubber with
petroleum products. Ind. Eng. Chem. 41:598.
Saffiotti, U. (1969). Experimental respiratory tract carcinogenesis.
Progr. Exp. Tumor Res. 11:302-33.
Sakabe, H., Tsuchiya, K., Takekura, N., Nomura, S., Koshi, S., Takemoto, K. ,
Matsushita, H., and Matsuo, Y. (1975). Lung cancer among coke oven
workers. A report to Labour Standard Bureau, Ministry of Labour, Japan.
Industrial Health 13:57-68.
Sail, R.D., and Shear, M.J. (1940). Studies in carcinogenesis. XII.
Effect of the basic fraction of creosote oil on the production of
tumors in mice by chemical carcinogens. J. Natl. Cancer Inst. 1:45-55.
Sawicki, E. (1967). Airborne carcinogens and allied compounds. Archives
of Environmental Health 14:46-53.
Sawicki, E. , Atkins, P.R. , Belsky, T*A. , Friedel, R.A., Hyde, D.L.,
Monkman, J.L., Rasmussen, R.A., Ripperton, R.A., Sigsby, J.E., and
White, L.D. (1974). Tentative methods of analysis for polynuclear
aromatic hydrocarbons in coke oven effluents. Health Lab. Science
11:218.
Sawicki, E., Corey, R.C., Dooley, A.E., Gisclard, J.B., Monkman, J.L.,
Neligan, R.E., and Ripperton, L.A. (1970a). Tentative method of
analysis for polynuclear aromatic hydrocarbon content of atmospheric
particulate matter. Health laboratory Science 7:31.
Sawicki, E., Corey, R.C., Dooley, A.E., Gisclard, J.B., Monkman, J.L.,
Neligan, R.E., and Ripperton, L.A. (1970b). Tentative method of
routine analysis for polynuclear aromatic hydrocarbon content of
atmospheric particulate matter. Health Laboratory Science 7:45.
Sawicki, E., Corey, R.C., Dooley, A.E. , Gisclard, J.B., Monkman, J.L.
Neligan, R.E., and Ripperton, L.A. (1970c). Tentative method of
microanalysis for benzo(a)pyrene in airborne particulates and source
effluents. Health Laboratory Science 7:56.
Sawicki, E., Corey, R.C., Dooley, A.E., Gisclard, J.B., Monkman, J.L.,
Neligan, R.E., and Ripperton, L.A. (1970d). Tentative method of
chromatographic analysis for benzo(a)pyrene and benzo(k)fluoranthene
in atmospheric particulate matter. Health Laboratory Science 7:60
Sawicki, E., Corey, R.C., Dooley, A.E., Gisclard, J.B., Monkman, J.L.,
Neligan, R.E., and Ripperton, L.A. (1970e). Tentative method of
spectrophotometric analysis for benzo(a)pyrene in atmospheric particulate
matter. Health Laboratory Science 7:63.
Sawicki, E., Fox, F.T., Elbert, W., Hauser, T.R. , and Meeker, J. (19621.
Polynuclear aromatic hydrocarbon composition of air polluted by coal-tar
pitch fumes. American Industrial Hygiene Association Journal 23:482-86.
Sawicki, E., Meeker, J.E., and Morgan, M.J. (1965). The quantitative
composition of air pollution source effluents in terms of aza heterocyclic
compounds and polynuclear aromatic hydrocarbons. Int. J. Air. Wat. Poll.
9:291-98.
-------
- 218 -
Sawicki, C.R., and Sawicki, E. (1972). Thin layer chromatography in
air pollution research. In Neiderwieser, A., and Pataki, G., Eds.:
Progress in Thin-Layer Chromatography and Related Methods, Vol. III.
Ann Arbor, Michigan, Ann Arbor Science Publishers, pp. 233-93.
Sawicki, E., Stanley, T.W., Elbert, W.C., and Pfaff, J.D. (1964).
Application of thin-layer chromatography to the analysis of atmospheric
pollutants and determination of benzo(a)pyrene. Analytical Chemistry
36, No. 3:497-502.
Schaaf, F. (1957). Akanthosetest mit Teer und Teerkohlenwasserstoffen.
Dermatologica 115:374-81.
Schamberg, J.F. (1910). Cancer in tar workers. J. Cutan. Diseases 28:
644-60.
Schamp, N., and Van Wassenhove, F. (1972). Determination of benzo(a)pyrene
in bitumen and plants. J. Chromatogr. 69:421-25.
Schmidt-Collerus, J.J. (1974). The disposal and environmental effects
of carbonaceous solid wastes from commercial oil shale operations.
First Annual Report, NSF GI 34282X1. National Science Foundation, 247 pp.
Schmit, J.A., Henry, R.A., Williams, R.C., and Dieckman, J.F. (1971).
Applications of high speed reversed-phase liquid chromatography.
Journal of Chromatographic Science 9:645.
Schulte, K.A., Larsen, D.J., Hornung, R.W., and Crable, J.V. (1974).
Report on analytical methods used in a coke oven effluent study. The
five oven study. U.S. Public Health Service Publ. No. HEW(NIOSH)74-105.
Schulte, K.A., Larsen, D.J., Hornung, R.W., and Crable, J.V. (1975).
Analytical methods used in a study of coke oven effluent. American
Industrial Hygiene Association Journal 36:131-9.
Schwarz, F.P., and Wasik, S.P. (1976). Fluorescence measurements of
benzene, naphthalene, anthracene, pyrene, fluoranthene, and benzo(e)pyrene
in water. Analytical Chemistry 48:524-28.
Schweighardt, F.K., Bockrath, B.C., Friedel, R.A., and Retcofsky, H.L. (1976)
Deuterium magnetic resonance spectrometry as a tracer tool in coal
liquefaction processes. Analytical Chemistry 48:1254-55.
Schweyer, H.E. (1975). Asphalt. Analytical Chemistry, Application Reviews
47:180R-183R.
Seeboth, H. (1963). Thin-layer chromatography of phenols. Chem. Techn.
(Berlin) 15:34-5.
Seim, H.J., Hanneman, W.W., Barsotti, L.R., and Walker, T.J. (1974). Deter-
mination of pitch volatiles in airborne particulate. I. Problems with
the benzene-soxhlet extraction method. American Industrial Hygiene
Association Journal 35:718-23 (Nov.).
-------
- 219 -
Seim, H.J., Hanneman, W.W., Barsotti, L.R., and Walker, T.J. (1975a).
Determination of pitch volatiles in airborne particulate. II. A
combined gravimetric and gas chromatographic determination of particulate
polycyclic organic matter (PPOM). Presented at American Industrial
Hygiene Conference in Minneapolis, Minnesota, June 3.
Seim, H.J., Hanneman, W.W., Barsotti, L.R., and Walker, T.J. (1975b).
Determination of pitch volatiles in airborne particulate. III. A
critical study of factors affecting the collection of coal tar pitch
volatiles (CTPV) in air. Presented at American Industrial Hygiene
Conference in Minneapolis, Minnesota, June 3.
Selikoff, I.J. (1976). Epidemiological studies. B. Roofers study.
In Industrial Health Foundation: Proceedings of the Symposium on
Particulate Polycyclic Organic Matter, Pittsburgh, PA, April 29-30,
1975, pp. 78-85.
Severson, R.F., Snook, M.E., Arrendale, R.F., and Chortyk, O.T. (1976).
Gas Chromatographic Quantitation of Polynuclear Aromatic Hydrocarbons
in Tobacco Smoke. Analytical Chemistry 48, No. 13:1866.
Sexton, R.J. (1960a). The hazards to health in the hydrogenation of
coal. I. An introductory statement on general information, process
description, and a definition of the problem. Archives of Environmental
Health 1:181-86.
Sexton, R.J. (1960b). The hazards to health in the hydrogenation of
coal. IV. The control program and the clinical effects. Archives of
Environmental Health 1:208-31.
Shabad, L.M., Khesina, A.Ja., Linnik, A.B., and Serkovskaya, G.S. (1970).
Possible carcinogenic hazards of several tars and of Lococorten-Tar
ointment (spectro-fluorescent investigations and experiments in animals).
Int. J. Cancer 6:314-18.
Sharkey, A.G., Jr., Shultz, J.L., Schmidt, C.E., and Friedel, R.A. (1975).
Mass spectrometric analysis of streams from coal gasification and
liquefaction processes. Pennsylvania, Pittsburgh Energy Research Center
Publication PERC/RI-75-5.
Shubik, P., Saffiotti, U., Lijinsky, W., Pietra, G., Rappaport, H., Toth, B.,
Raha, C.R., Tomatis, L., Feldman, R., and Ramahi, H. (1962). Studies on
the toxicity of petroleum waxes. Toxicology and Applied Pharmacology
4, Supplement, Nov., 62 pp.
Shuler, P.J. (1973). Industrial hygiene survey, Ormet Corporation Aluminum
Facilities, Hannibal, Ohio. U.S. National Institute for Occupational
Safety and Health, Division of Field Studies and Clinical Investigations,
Cincinnati, Ohio.
Shuler, P.J., and Bierbaum, P.J. (1974). Environmental surveys of aluminum
reduction plants. HEW Publication No. (NIOSH) 74-101. National Institute
for Occupational Safety and Health, Division of Field Studies and Clinical
Investigations, Cincinnati, Ohio. Washington, D.C., Government Printing
Office.
-------
- 220 -
Shults, W.D. (1975). Preliminary results: chemical and biological
examination of coal-derived materials. Oak Ridge National Laboratory
Report ORNL/NSF/EATC-18. Oak Ridge, Tennessee.
Shultz, J.L., Friedel, R.A., and Sharkey, A.G., Jr. (1967). Mass
spectrometric analyses of coal-tar distillates and residues. U.S.
Bureau of Mines, Report of Investigations No. 7000, 14 pp.
Shultz, J.L., Kessler, T., Friedel, R.A., and Sharkey, A.G., Jr. (1972).
High-resolution mass spectrometric investigation of heteroatom species
in coal-carbonization products. Fuel (London) 51:242-46.
Silverstein, R.M., and Bassler, G.C. (1967). Spectrometric Identification
of Organic Compounds, 2nd ed. New York, John Wiley and Sons, Inc., 256 pp.
Simmers, M.H. (1964). Petroleum asphalt inhalation by mice. Effects of
aerosols and smoke on the tracheobronchial tree and lungs. Archives of
Environmental Health 9:727-34.
Simmers, M.H. (1965a). Cancers from air-refined and steam-refined asphalt.
Industrial Medicine and Surgery 34, No. 3:255-61.
Simmers, M.H. (1965b). Cancers in mice from asphalt fractions. Industrial
Medicine and Surgery 34, No. 7:573-7.
Simmers, M.H. (1966). Tumors from asphalt fractions injected into mice.
Industrial Medicine and Surgery 35, No. 10:889-94.
Simmers, M.H., Podolak, E., and Kinosita, R. (1959). Carcinogenic effects
of petroleum asphalt. Proc. Soc. Exp. Biol. Med. 101:266-8.
Simpson, C.F., Ed. (1976). Practical High Performance Liquid Chromatography.
London, U.K., Heyden and Sons, Ltd., 315 pp.
Skin Allergy News (1977). Carcinogenicity of coal tar is discounted. 8:1,
24-25 (Oct.). (From Industrial Hygiene Digest 41, No. 12, 1977)
Slavin, W., Williams, A.T.R. , and Adams, R.F. (1977). A fluorescence
detector for high-pressure liquid chromatography. Journal of Chromatography
134:121-30.
Smith, D.B., and Schweyer, H.E. (1967). Certain chemical aspects of
processing asphalt. American Chemical Society, Division of Petroleum
Chemistry, Preprints 12, No. 2:A35-A50.
Smith, F.A., Eckle, T.F., Osterholm, R.J. , and Stickel, R.M. (1966).
Manufacture of coal tar and pitches. In Hoiberg, A.J., Ed.: Bituminous
Materials: Asphalts, Tars, and Pitches. Vol. III. Coal Tars and Pitches.
New York, Interscience Publishers, pp. 57-116.
Snook, M.E., Chamberlain, W. J. , Severson, R.F., and Choutyk, O.T. (1975).
Chromatographic concentration of polynuclear aromatic hydrocarbons of
tobacco smoke. Analytical Chemistry 47:1115-57.
-------
- 221 -
Soedigdo, S., Angus, W.W., and Flesher, J.W. (1975). High-pressure liquid
chromatography of polycyclic aromatic hydrocarbons and some of their
derivatives. Analytical Biochemistry 67:664-68.
Spink, M.S., Baynes, A.H., and Tombleson, J.B.L. (1964). Skin carcinoma in
the process of 'Stanford jointing.1 British Journal of Industrial
Medicine 21:154-57.
Spitzer, W.O. , Hill, G.B., Chambers, L.W., Helliwell, B.E., and Murphy, H.B.
(1975). The occupation of fishing as a risk factor in cancer of the lip.
New England Journal of Medicine 293:419-24.
Stanley, T.W., Meeker, J.E., and Morgan, M.J. (1967). Extraction of organics
from airborne particulates; effects of various solvents and conditions
on the recovery of benzo(a)pyrene, benz(c)acridine, and 7H-benz(de)-
anthracen-7-one. Environmental Science and Technology 1:927-31.
Sterba, M.J. (1974). Petroleum processing. In Considine, D.M. , Ed.:
' Chemical and Process Technology Encyclopedia. N.Y., McGraw-Hill, pp. 856-61.
Stone, O.J., and Anthony, J.A. (1970). The effect of tar on wound healing.
Archives of Environmental Health 20:602-3.
Stone, 0.J., and Willis, C.J. (1969). The effect of tar on infection.
Toxicology and Applied Pharmacology 15:677-78.
Stoughton, R.B. , DeQuoy, P., and Walter, J.F. (1978). Crude coal tar plus
near ultraviolet light suppresses DNA synthesis in epidermis. Arch.
Dermatol. 114:43-5.
Stroemberg, L.E., and Widmark, G. (1970). Quantitative determination of
3,4-benzopyrene in the air near gas-works retorts. Journal of Chroma-
tography 49 : 334-40.
Suatoni, J.C., and Garber, H.R. (1976). Hydrocarbon group-type analysis of
petroleum fractions [b.p. 190°-360°C] by high performance liquid chroma-
tography. Journal of Ghromatographic Science 14:546-48.
Suatoni, J.C., and Swab, R.E. (1975). Rapid hydrocarbon group-type analysis
by high performance liquid chromatography. Journal of Chromatographic
Science 13:361-66.
Suatoni, J.C., and Swab, R.E. (1976). Preparative hydrocarbon compound type
analysis by high performance liquid chromatography. Journal of Chromato-
graphic Science 14:535-37.
Suhonen, R. (1976). Photoepicutaneous testing. Influence of the vehicle
occlusion time and concentration of the test substances on the results.
:- Contact Dermatitis 2:218-26.
Susorov, N.A. (1970). (Mass injury to the organ of vision by coal tar pitch.)
Voennomed. Zn. 3:75. .
Swain, A.P., Cooper, J.E., and Stedman, R.L. (1969). Large-scale fractiona-
tion by cigarette smoke condensate for chemical and biologic investigations.
Cancer Research 29:579-83.
-------
- 222 -
Swanbeck/ G. (1971). Aetiological factors in squamous cell skin cancer.
Br. J. Derm. 85:394-6.
Tanimura, H. (1968). Benzo(a)pyrene in an iron and steel works. Archives
of Environmental Health 17:172-7.
Thomas, J.F., and Mukai, M. (1975). Evaluation of emissions from asphalt
roofing kettles with respect to air pollution. The Asphalt Institute
Research Report 75-2 (RR-75-2). College Park, Maryland.
Thomas, J.F., Mukai, M., and Tebbens, B.D. (1968). Airborne benzo(a)pyrene.
Environmental Science and Technology 2:33-39.
Thomas, R.S., and Lao, R.C. (1977). The application of high-pressure liquid
chromatography (HPLC) and gas chromatography (GC) to the analysis of
polycyclic aromatic hydrocarbons in fossil fuel conversion processes. In
Gammage, R.B. (1977), pp. 77-82.
Traxler, R.N., and Schweyer, H.E. (1953). Oil Gas J. 52:158. (Cited in
Hoiberg et al., 1963, p. 804.)
Traxler, R.N., and Scrivener, F.H. (1971). American Chemical Society,
Division of Petroleum Chemistry, Preprints 16, No. 1:D102.
Traxler, R.W. (1964). Microbial action on bituminous materials. In
Hoiberg, A.J., Ed.: Bituminous Materials: Asphalts, Tars, and Pitches.
Vol. I. New York, Interscience Publishers, pp. 323-46.
Traxler, R.W., Proteau, P.R. , and Traxler, R.N. (1965). Action of micro-
organisms on bituminous materials. I. Effect of bacteria on asphalt
viscosity. Applied Microbiology 13:838-41.
TRW Systems and Energy (1976). Carcinogens relating to coal conversion
processes. U.S. Energy Research and Development Administration Report
No. FE-2213-1. Available from the National Technical Information Service.
Tsutsui, H. (1918) . Kurze Inhaltsangabe der Originalaufsatze. tJber das
kiinstlich erzeugte Cancroid bei der Maus. Gann 12:17-21.
Tye, R., Horton, A.W., and Rapien, I. (1966). Benzo(a)pyrene and other
aromatic hydrocarbons extractable from bituminous coal. American
Industrial Hygiene Association Journal 27:25-8.
Tye, R., and Stemmer, K.L. (1967). Experimental carcinogenesis of the lung.
II. Influence of phenols in the production of carcinoma. Journal of the
National Cancer Institute 39, No. 2:175-86.
Tynan, B.C., and Yen, T.F. (1969). Association of vanadium chelates in
petroleum asphaltenes as studied by E.S.R. Fuel (London) 48, No. 2:
191-208.
U.S. Bureau of Census (1975). Petroleum and coal products. Census of
Manufactures, 1972, Industry Series No. MC72(2)-29A.
-------
- 223 -
U.S. Bureau of the Census (1976). TCC 295. Asphalt paving and roofing
material. In 1972 Census of Transportation. Vol. III. Commodity
Transportation Survey. Part 1. Commodity and Special Statistics,
pp. 8-17, 8-18.
U.S. Bureau of Mines (1975). Coke and Coal Chemicals. Preprint from
the 1974 Bureau of Mines Minerals Yearbook. Washington, D.C.,
U.S. Government Printing Office, 38 pp.
U.S. Bureau of Mines (1954-1976). Sales of asphalt. Division of Fuels
Data, Mineral Industry Surveys. Washington, D.C., U.S. Bureau of Mines.
U.S. Bureau of Mines (1976). Petroleum refineries in the United States
and Puerto Rico. Division of Fuels Data, Mineral Industry Surveys.
Washington, D.C., U.S. Bureau of Mines, 17 pp.
U.S. Department of Labor, Occupational Safety and Health Administration
(1972). Coal tar pitch volatiles. Federal Register 37:24739.
U.S. Department of Labor, Occupational Safety and Health Administration
(1975). Exposure to coke oven emissions; proposed standard. Federal
Register 40:32267-82.
U.S. Department of Labor, Occupational Safety and Health Administration
(1976). Occupational Safety and health standards. Exposure to coke
oven emissions. Federal Register 41:46741-90.
U.S. Department of Labor, Occupational Safety and Health Administration
(1977). Selected general industry safety and health standards.
Proposed revocation. 29 CFR Part 1910, Subpart 2 - Toxic and hazardous
substances, par. 1910.1000 Air contaminants; par. 1910.1002 Coal tar
pitch volatiles, interpretation of term; par. 1910.1029 Coke oven
emissions. Federal Register 42:62868-70; 68271; 62886-90 (Dec. 13).
U.S. Department of Transportation (1975a). Flammable, combustible, and
pyrophoric liquids; definitions. Federal Register 40:22263-65.
U.S. Department of Transportation (1975b). Asphalts in cargo tanks.
Federal Register 40:59598.
U.S. Environmental Protection Agency (1974). Standards of performance
for new stationary sources. Opacity provisions. Federal Register
39:39872-75.
U.S. Environmental Protection Agency (1975a). Standards of performance for
new stationary sources of air pollution. Opacity provisions; request for
public comment. Federal Register 40:17778-81.
U.S. Environmental Protection-Agency (1975b). Effluent limitations
quidelines for existing sources and standards of performance and
pretreatment standards for new sources for the paving and roofing
materials (tars and asphalt) point source category." Federal Register
40:31190-95.
-------
- 224 -
U.S. Environmental Protection Agency U977). Control of volatile organic
compounds from use of cutback asphalt. Report No. EPA-450/2-77-037, 16 pp.
U.S. National Technical Information Service Report PB-278 185.
U.S. International Trade Commission (1954-1977). Tar and tar crudes. In
Synthetic Organic Chemicals. United States Production and Sales, USITC
Publication (formerly U.S. Tariff Commission).
U.S. National Institute for Occupational Safety and Health (1973). Criteria
for a recommended standard. Occupational Exposure to coke oven emissions.
Report No. HSM 73-11016. Washington, D.C., U.S. Government Printing
Office, 58 pp.
U.S. National Institute for Occupational Safety and Health (1976). In
Christensen, H.E., and Fairchild, E.J., eds.: Registry of Toxic Effects
of Chemical Substances, 1976 ed. Washington, D.C. , U.S. Government
Printing Office.
U.S. National Institute for Occupational Safety and Health (1977a). Criteria
for a recommended standard...occupational exposure to asphalt fumes. DHEW
CNIOSH) Publication No. 78-106. Washington, D.C., U.S. Government Printing
Office, 143 pp.
U.S. National Institute for Occupational Safety and Health (1977b). Criteria
for a recommended standard...occupational exposure to coal tar products.
DHEW (NIOSH) Publication No. 78-107. Washington, D.C., U.S. Government
Printing Office, 189 pp.
U.S. Office of Management and Budget (1972). Standard Industrial
Classification Manual. Washington, D.C., U.S. Government Printing
Office, 649 pp.
Vahrman, M. (1958). Chemistry of coal tars. III. Preliminary examination
of the neutral, pentane-soluble fraction from down-jet tar. Journal of
Applied Chemistry 8:485-92.
Vallerga, B.A., Monismith, C.L., and Granthem, K. (1957). Proc. Assoc.
Asphalt Paving Technologists 26:126. (Cited in Wright, 1965, p. 303).
Vaughan, C.G., Wheals, B.B. , and Whitehouse, M.J. (1973). The use of
pressure-assisted liquid chromatography in the separation of polynuclear
hydrocarbons. Journal of Chromatography 78:203-10.
Vo-Dinh, T. (1977). Recent progress in room temperature phosphorimetry for
analysis of PNA. In Gammage, R.B. (1977) , pp. 105-9.
Vogh, J.W., and Dooley, J.E. (1975). Separation of organic sulfides from
aromatic concentrates by ligand exchange chromatography. Analytical
Chemistry 47:816-21.
von Lehmden, D.J., Hangebrauck, R.P., and Meeker, J.E. (1965). Polynuclear
hydrocarbon emissions from selected industrial processes. Journal of
the Air Pollution Control Association 15, No. 7:306-12.
-------
- 225 -
Waibel, M. (1976). Luft- und Gewasserverunreinigung durch 3.4-Benzpyren-
haltigen Strassenabrieb. Zbl. Bakt. Hyg., I. Abt. Orig. B 163:458-69.
Walker, J.D., Colwell, R.R., and Petrakis, L. (1975a). Degradation of
petroleum by an alga, Prototheca zopfii. Applied Microbiology 30:79-81.
Walker, J.D., Colwell, R.R., and Petrakis, L. (1975b). Microbial petroleum
degradation: application of computerized mass spectrometry. Can. J.
Microbiol. 21:1760-7.
Wallcave, L. (1969) . Gas chromatographic analysis of polycyclic aromatic
hydrocarbons in soot samples. Environmental Science and Technology
3:948.
Wallcave, L. (1975). Remarks on presentation by Barry Commoner. In Workshop
on Health Effects of Coal and Oil Shale Mining, Conversion, Utilization,
University of Cincinnati, Cincinnati, Ohio, Jan- 27-29.
Wallcave, L., Garcia, H., Feldman, R., Lijinsky, W., and Shubik, P. (1971).
Skin tumorigenesis in mice by petroleum asphalts and coal-tar pitches of
known polynuclear aromatic hydrocarbon content. Toxicology and Applied
Pharmacology 18, No. 1:41-52.
Waller, R.E. (1952). The benzo(a)pyrene content of town air. British
Journal of Cancer 6:8-21.
Warner, J.S. (1976). Determination of aliphatic and aromatic hydrocarbons
in marine organisms. Analytical Chemistry 48:578-83.
Wehry, E.L., and Mamantov, G. (1977). Matrix isolation fluorescence and
fourier transform infrared analysis of polycyclic aromatic hydrocarbons.
In Gammage, R.B. (1977), pp. 91-3.
Wehry, E.L., Mamantov, G., Kemmerer, R.R., Brotherton, H.O. , and Stroupe, R.C.
(1976). Low temperature fourier transform infrared spectroscopy of
polynuclear aromatic hydrocarbons. In Freudenthal, R. , and Jones, P.W. :
Carcinogenesis - A comprehensive Survey, Vol. 1. New York, Raven Press,
pp. 299-309.
Weil, C.S., and Condra, N.I. (1960). The hazards to health in the hydrogena-
tion of coal. II. Carcinogenic effect of materials on the skin of mice.
Archives of Environmental Health 1:187-93.
Wheals, B.B., Vaughan, C.G., and Whitehouse, M.J. (1975). Use of chemically
modified microparticulate silica and selective fluorimetric detection
for the analysis of polynuclear hydrocarbons by high-pressure liquid
chromatography. Journal of Chromatography 106:109-18.
White, L.D. (1972). Coke-oven emissions, occupational health and the
environment. Master's Thesis. University of Cincinnati, 131 pp.
White, L.D. (1975). The collection, separation, identification and
quantitation of selected polynuclear aromatic hydrocarbons and metals
in coal tar and coke-oven emissions. Dissertation, University of
Cincinnati, Cincinnati, Ohio, 222 pp.
-------
- 226 -
Wolsky, A.A., and Chapman, F.W., Jr. (1960). Study of an intrinsic
contaminant petroleum; nature of vanadium in asphaltenes. Proc. Am.
Petrol. Inst. 40, Sect. 111:423-7.
Wright, J.R. (1965). Weathering: Theoretical and practical aspects of
asphalt durability. In Hoiberg, A.J., Ed.: Bituminous Materials:
Asphalts, Tars, and Pitches, Vol. II. Asphalts, Part 1. New York,
Interscience Publishers, pp. 249-306.
Yamagiwa, K. , and Ichikawa, K. (1915) . Experimentelle Studie iiber die
Pathogenese der Epithelialgeschwulste. Mitt. Med. Fak., Kaiserlich
Univ. Tokyo 15:295.
Yamagiwa, K., and Ichikawa, K. (1918). Experimental study of the patho-
genesis of carcinoma. Journal of Center Research 3:1-21.
Yen, T.F. (1972). Vanadium chelates in recent and ancient sediments. In
Hemphill, D.D. , Ed.: Trace Substances in Environmental Health - VI.
Proceedings of University of Missouri's 6th Annual Conference on Trace
Substances in Environmental Health, Columbia, Missouri, June 13-15,
pp. 347-53.
Young, E. (1972). Ultraviolet therapy of psoriasis: a critical study.
Br. J. Derm. 87:379-82.
Youssef, M.H., El-Kassas, A.G., Rushdy, M.I., and Abdou, I.K. (1976).
Aromatic hydrocarbons from high boiling petroleum distillates.
Revue Roumaine de Chimie 21:263-67.
Zackheim, H.S. (1978). Should therapeutic coal-tar preparations be
available over-the-counter? Letters to the Editor. Archives of
Dermatology 114:125-26 (Jan,)
Zafiriou, O.C. (1973). Improved Method for Characterizing Environmental
Hydrocarbons by Gas Chromatography. Analytical Chemistry 45, No. 6:
952-56.
Zander, M. (1968). Phosphorimetry. New York, Academic Press.
Zeglio, P. (1950). Changes in the respiratory tract from bitumen vapors.
Rass. Med. Ind. 19:268-73.
Zesch, A. (1972). Local adsorption and resorption of coal tar following
tar baths. Z. Haut. Geschlechtskr. 47, No. 13:551-57.
Zielinski, W.L., Jr., Johnszon, K., and Muschik, G.M. (1976). Nematic
liquid crystal for gas-liquid chromatographic separation of steroid
epimers. Analytical Chemistry 48:907-11.
ZoBell, C.E. (1971). Sources and biodegradation of carcinogenic hydro-
carbons. In Proceedings of the Joint Conference of Prevention and
Control of Oil Spills, pp. 441-52.
Zoccolillo, L., and Liberti, A. (1976). Determination of polycyclic
hydrocarbons by channel thin-layer chromatography. Journal of
Chromatography 120:485-88.
-------
- 227 -
Zoccolillo, L. , Liberti, A., and Brocco, D. (1972). Determination of
polycyclic hydrocarbons in air by gas chromatography with high
efficiency packed columns. Atmospheric Environment 6:715-20.
Zorn/ H. (1966). (Carcinoma of urinary passage in tar, asphalt, and
bitumen workers.) Zentrabl. Arbeitsmed. Arbeitsschutz 16, No. 12:
366-71.
Zubovic, P. (1975). Geochemistry of Trace Elements in Coal. U.S. Geological
S urvey, Res ton, Va.
-------
- 228 -
LIST OF INFORMATION SOURCES
Reference Works
Analytical Chemistry. Annual Reviews
Braunstein, H.M., Copenhaver, E.D., and Pfuderer, H.S. (1976).
Environmental, health, and control aspects of coal conversion:
An information overview. Volume 1. U.S. Energy Research and
Development Administration, Oak Ridge National Laboratory, Publ.
No. ORNL/EIS-94 (draft), Oak Ridge, Tennessee.
Clar, E.J. (1964). Polycyclic Hydrocarbons. New York, Academic Press.
2 vols.
Considine, D.M., Ed. (1974). Chemical and Process Technology
Encyclopedia. New York, McGraw-Hill.
Danielson, J.A., Ed. (1973). Air Pollution Engineering Manual. 2nd ed.
U.S. Environmental Protection Agency Publication No. AP-40, 987 pp.
Eckardt, R.E. (1959). Industrial Carcinogens. New York, Grune and
Stratton, 164 pp.
Encyclopaedia Britannica (1969; 1974). Chicago, Illinois, William
Benton; Helen Benton.
Encyclopedia Polymer Science and Technology (1965). Volume 2: Plastics,
Resins, Rubbers, and Fibers. New York, Interscience Publishers.
Friedel, R.A., and Orchin, M. (1951). Ultraviolet Spectra of Aromatic
Compounds. New York, John Wiley and Sons, Inc.
Gary, J.H., and Handwerk, G.E. (1975). Petroleum Refining. Technology
and Economics. New York, Marcel Dekker, Inc.
Hobson, G.D., Ed. (1973). Modern Petroleum Technology. 4th ed. New York,
Halsted Press, 996 pp.
Hoiberg, A.J., Ed. (1964). Bituminous Materials: Asphalts, Tars, and
Pitches. Vol. I. New York, Interscience Publishers, 432 pp.
Hoiberg, A.J., Ed. (1965). Bituminous Materials: Asphalts, Tars,
and Pitches. Vol. II. Asphalts. Part 1. New York, Interscience
Publishers, 698 pp.
Hoiberg, A.J., Ed. (1966). Bituminous Materials: Asphalts, Tars,
and Pitches. Vol. III. Coal Tars and Pitches. New York, Interscience
Publishers, 585 pp.
Industrial Health Foundation, Inc. (1976). Proceedings of the Symposium
on Particulate Polycyclic Organic Matter, Pittsburgh, Pennsylvania,
April 29-30, 1975.
-------
- 229 -
International Agency for Research on Cancer (1972-). IARC Monographs
on the Evaluation of Carcinogenic Risk of Chemicals to Man. Lyon,
France, International Agency for Research on Cancer.
International Labor Office (1971, 1972). Encyclopaedia of Occupational
Health and Safety, Geneva, Switzerland. 2 vols.
Jones, H.R. (1973). Pollution Control in the Petroleum Industry.
Park Ridge, New Jersey, Noyes Data Corporation.
Kirk-Othmer Encyclopedia of Chemical Technology (1963-70). 2nd ed.
New York, Interscience Publishers. 22 vols.
McGannon, H.E., Ed. (1971). The Making, Shaping, and Treating of Steel.
Pittsburgh, Pennsylvania, Herbick and Held.
McGraw-Hill Encyclopedia of Science and Technology (1977). 10 vols.
New York, McGraw-Hill, Inc.
McNeil, D. (1966) . Coal Carbonization Products. New York, Pergamon
Press, 159 pp.
National Research Council, Committee on Biologic Effects of Atmospheric
Pollutants (1972). Particulate Polycyclic Organic Matter. Washington,
D.C., National Academy of Sciences, 361 pp.
National Research Council, Committee on Biologic Effects of Atmospheric
Pollutants (1974). Vanadium. Washington, D.C., National Academy
of Sciences, 117 pp.
National Research Council, Committee on Medical and Biologic Effects of
Environmental Pollutants (1975). Nickel. Washington, D.C., National
Academy of Sciences, 277 pp.
National Safety Council (1974). Accident Prevention Manual for Indus-
trial Operations. 7th ed. Chicago, Illinois, National Safety Council.
Oak Ridge National Laboratory (1976). First OFNL Workshop on Polycyclic
Aromatic Hydrocarbons: Characterization and Measurement with a View
Toward Personnel Protection. Publication No. ORNL/TM-5598, Oak Ridge
Tennessee.
Oak Ridge National Laboratory (1977). Workshop on Exposure to Polynuclear
Aromatic Hydrocarbons in Coal Conversion Processes. Oak Ridge,
Tennessee, March 9-11.
Oglesby, C.H. (1975). Highway Engineering. 3rd ed. New York, John Wiley
and Sons.
Schwartz, L., £t al. (1957). Occupational Diseases of the Skin. 3rd ed.
Philadelphia, Pennsylvania, Lea and Febiger.
Sittig, M. (1974). Pollution Detection and Monitoring Handbook. Park
Ridge, New Jersey, Noyes Data Corporation, pp. 331-39.
-------
- 230 -
Secondary Sources
Manual Sources
Bulletin of Hygiene 1968-1974
Chemical Abstracts 1952-1977
Engineering Index 1973-1976
ERA Research Abstracts 1976-1977 (formerly ERDA Energy Research Abstracts)
Excerpta Medica, 1971-1977
Section 46, Environmental Health and Pollution Control
Section 35, Occupational Health and Industrial Medicine
Index Medicus 1970-1976
Predicasts 1970-1976
Science Citation Index 1970-1976
U.S. Bureau of Mines Catalog of Special Publications 1970-1976
U.S. Government Publications Monthly Catalog 1969-1976
U.S. Government Reports Announcements 1972-1974
Veterinary Bulletin 1959-1971
Weekly Government Abstracts; Environmental Pollution and Control;
Medicine and Biology, 1976-1977
Automated Data Bases
TOXLINE 1966-1976
MEDLINE 1966-1976
CANCERLINE
U.S. NIOSH
-------
TECHNICAL REPORT DATA
(I'icac rend Jiijtniilivni on tin: ri'imc bcjort.-
\. Hi t'ORT UO.
EPA-560/2-77-005
2.
3. HhCIPILNT'S ACCESSION NO.
4. TITLt AND SUBTITLE
Investigation of Selected Potential Environmental Con-
taminants: Asphalt and Coal Tar Pitch
5. RLPORT DATE
September, 1978
5. PERFORMING ORGANIZATION COUE
7. AUTHOR(S)
Ruth P. Trosset, David Warshawsky, Constance Lee Menefee,
Eula Bingham
R. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Environmental Health
University of Cincinnati College of Medicine
3223 Eden Avenue
Cincinnati, Ohio 45267
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Toxic Substances
U.S. Environmental Protection Agency
Washington, D.C. 20460
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-4188
13. TYPE OF REPORT AND PERIOD COVERED
-Final Technical Rp.pnrt
14. SPONSORING AGENCY
1£> SUPPLEMENTARY NOTES
16. ABSTRACT
This report reviews the literature on the potential environmental hazards and health
impacts from production, distribution, and use of asphalt, the essentially uncracked
residue from crude oil, and coal tar pitch, the highly cracked residue from fractional
distillation of coal tar derived from the coking of coal. Topics include physical and
chemical properties; production figures; uses; process descriptions; contamination
potential; methods of sampling, monitoring, and analysis; acute and chronic effects on
human health; toxicity to animals and plants; suggested handling practices; regulations
and standards.
Of the 31 million tons of asphalt sold annually in the US, most is used in exposed
surfaces: paving (78%), roofing (17%), dam linings and soil stabilizers, etc. (<5%).
In contrast, 62% of the 1.2 million tons of pitch produced annually in the US is used
in baked carbon and graphite products, 17% as fuel, and only 7% in exposed surfaces.
Asphalt and pitch and their emissions and degradation products may contain varying
quantities of trace metals and polycyclic aromatic hydrocarbons (PAH) , some of which
may have toxic effects including phototoxicity and cancer of skin and lungs. Potential
environmental contamination and health hazards of asphalt and pitch are considered,
with recommendations for further research.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Asphalt
Coal tar pitch
Polynuclear aromatic hydrocarbons
Benzo(a)pyrene
Trace metals
Pollution
Environmental effects
Carcinogenicity
Phototoxicity
8. DISTRIBUTION STATEMENT
Document is available to public through
National Technical Information Service
L.Springfield, Va,
19. SECURITY CLASS (fins licporll
Unclassified
70. SECURITY CLASS. (Tins pagcf
Unclassified
21. NO. OF PAGE:
227"PR 1C E
EPA Fo-m 2220-1 (Rt«. 4-77) pncvioui ron ION 11
------- |