645R79003
POLYCYCLIC ORGANIC MATTER:
REVIEW AND ANALYSIS
by
J. 0. Milliken and E. G. Bobalek
Special Studies Staff
Office of Program Operations
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
February 1979
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11
CONTENTS
Page
Executive 'Summary iv
Measurement of POM iv
Sources of POM v
Ambient Concentrations of POM . vii
Exposure to POM viii
Health Effects of POM x
Recommendations xii
Recommendations for the Short-Term xii
Recommendations for the Long-Term xv
Acknowledgements xvi
Introduction 1
Background, 1
Definition of POM 1
Overview of Report 2
Objectives and Scope 4
Review and Analysis 7
Available Information 7
Chemical and Physical Properties of POMs. ... 10
Sources of POM 12
Ambient Concentration of POM 17
Health Effects of POMs 21
Conclusions 24
Measurement of POM. 24
Sources of POM. 25
Ambient Concentrations of POM 26
. Exposure to POM 27
Health Effects of POM 28
Recommendations 30
Recommendations for the Short-Term 30
Recommendations for the Long-Term 32
References . 34
Appendix A. Capillary-Column Gas Chromatograms of POM
Fractions from Combustion Products A-l
Appendix B. Ambient Concentration Data for POM. . B-l
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Ill
TABLES
Page
1. Estimates of Total Annual B(a)P Emissions from Major
Sources vi
2. Reported Environmental Concentrations of Benzo(a)pyrene. . ix
3. Estimated Daily Exposure to B(a)P, Carcinogenic PAH, and
Total PAH xi
4. Summary of Physico-Chemical Properties of Polycyclic
Aromatic Hydrocarbons and their Relevance to
Carcinogenesis 13
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IV
EXECUTIVE SUMMARY
The Glean Air Act Amendments of 1977 add Section 122, "Listing of
t
Certain Unregulated Pollutants," to Title I of the Clean Air Act (1).
This amendment directs the Administrator to "... review all available
relevant information and determine whether or not emissions of ...
polycyclic organic matter into the ambient air will cause, or contribute
to, air pollution which may reasonably be anticipated to endanger public
health."
The principal conclusion of this report is that, on the basis of
available information, emissions of polycyclic organic matter (POM) into
the ambient air cannot, at this time, be reasonably anticipated to
endanger public health. Because current uncertainties in the POM ex-
posure assessment data and in the health effects data present a risk
that this conclusion is incorrect, development of additional POM assess-
ment data is recommended. The rationale for this conclusion and spec-
ific recommendations for developing the requisite POM assessment data
base are set forth below.
Measurement of POM
Because POM in the ambient air consists of a large number of spec-
ific polycyclic organic compounds at very low concentrations and co-
exists with a broader spectrum of organic compounds, POM is very dif-
ficult to detect and quantify. Traditionally, the amount of POM has
been identified by measurement of benzo(a)pyrene [B(a)P], which is one
of many POM compounds, or by benzene soluble organics [BSD], which
represents a broader range of organic compounds. Because the relation
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VI
TABLE 1. ESTIMATES OF TOTAL ANNUAL B(a)P EMISSIONS FROM MAJOR
SOURCES3'b
Source
Current B(a)P Emissions (Mgc/yr)
Estimated Min.
. Estimated Max.
Burning Coal Refuse Banks
Coke Production
Residential Fireplaces
Forest Fires
Coal-fired Residential Furnaces
Rubber Tire Wear
Automobiles (gasoline)
Commercial Incinerators
280
0.050
52
9.5
0.85
0
1.6
.98
310
300
110
127
740
11
3.8
4.7
From reference 3.
Benzo(a)pyrene [B(a)P] is only one of many individual POM com-
pounds. Traditionally B(a)P has served as an indicator of total POM,
but this practice is questionable.
cmg = megagrams or metric ton.
Includes both wildfires and prescribed burning.
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wide ranges of estimates for B(a)P emission factors. Although the open
burning sources contribute a significant portion of total B(a)P emis-
sions, the temporal and spatial relationship of these sources to human
receptors diminishes their probable impact on public health.
Coal derived materials (e.g., coal tar, pitch, creosote, and soot)
and coal conversion processes (e.g., coking, gasification, and liquifi-
cation) are known sources of POM (6, 46, 47). Approximately 300 indi-
vidual POM compounds have been identified as products of coal carboni-
zation (coking) (48), and there are surely many more. Coal itself is
highly aromatic in chemical structure and is known to contain B(a)P and
other POMs (49), but most POMs from coal processes are chemically formed
during high temperature (700° C to 1500° C) pyrosynthetic conversion
reactions.
Coal gasification involves chemical reactions similar to carboni-
zation, and is also a source of POMs. The high boiling condensation
products of coal gasification contain POMs. Coal liquification products
and by-products, shale derived oil, and petroleum crude oil represent
additional energy related materials which contain POM (6, 26). Proper
design, construction, and maintenance of coal processing plants is
necessary to prevent the commercialization of coal and shale conversion
from becoming a new major source of POM.
Ambient Concentrations of POM
Trace levels of POM have been detected in air, water, and soil. In
air, POM is thought to exist primarily in a condensed phase, either
adsorbed onto particulate matter, especially soot, or condensed with
other organic compounds as an aerosol. Because POMs are formed in a
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vapor phase during high temperature combustion or pyrolysis processes
and condense or adsorb onto particulate matter, smaller particles, which
•
have a higher surface area to mass ratio, have a higher concentration of
POM per unit mass. These smaller particles are more apt to penetrate
deep into the lung during inhalation. The solubility of POMs in water
is very small, and consequently most POM in aquatic systems adsorbs on
particulates and in sediment. Typical levels of benzo(a)pyrene in the
environment are illustrated in Table 2.
Ambient air sampling of B(a)P or total POM is primarily by particu-
late capture on glass fiber filters. The recognized disadvantages of
this method are (1) inability to capture vapor phase POM, (2) chemical
reaction on the filter, and (3) desorption or stripping of POM from
particulate on the filter. All of these problems result in a loss of
detectable POM from the filter, and consequently, the reported values of
ambient concentrations probably underestimate the real situation.
Exposure to POM
Because significant uncertainty exists for POM source inventories
and ambient air concentrations, it is difficult to provide confident
estimates of human exposure to airborne POM. The existing data are
primarily for B(a)P emission factors and ambient B(a)P levels (e.g.,
references 1-3, 6), but the ratio of B(a)P to total POM is known to be
highly variable, ranging at least 1% to 20% (28). However, some ex-
posure estimates have been made for occupational settings. In addition
to cigarette smoking the greatest human exposures to airborne POM prob-
ably occur in certain occupations, viz., the top side of coke ovens,
coal tar pitch working, and hot asphalt paving (45). The total fraction
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IX
TABLE 2. REPORTED ENVIRONMENTAL CONCENTRATIONS OF BENZO(a)PYRENEc
t
Urban air
Rural aire
Groundwater
Surface water
f
Drinking water
Marine sediment
Soil
Minimum
0.02C ng/m3
N.D.g
.6 ng/1
N.D.g
1.53 ng/g soil
Maximum
2.4C ng/m3
4 ng/1
210 ng/lh
2.1 ng/1
350k ng/g soil
Mean
0.33d ng/m3
O.le ng/m3
2201 ng/g dry
sediment
Benzo(a)pyrene [B(a)P] is only one of many POM compounds. The use
of B(a)P as an indicator of total POM or of carcinogenic POM is questionable.
Urban air values are from the 32 National Air Surveillance Network
(NASN) urban sites that reported B(a)P concentrations during 1977. Con-
centrations reported by NASN are quarterly composite averages.
Q
Minimum and maximum values are for the 1977 NASN B(a)P quarterly
composite averages. The minimum is for Honolulu, Hawaii, second and
third quarter; the maximum is for Youngstown, Ohio, first quarter.
Geometric mean of 1977 NASN urban B(a)P values.
eThis value is from reference 53 and represents the average of
two rural locations for 1976.
Data from reference 53.
gN.D. = none detected at a detection limit of 1 ng/1.
Contaminated surface water concentrations of B(a)P have been
reported as high as 12000 ng/1 (53).
This value is from reference 54 and represents the average of two
sampling stations. Station A was 75 ng/g dry sediment and station B
was 370 ng/g dry sediment. Sampling location was Buzzard's Bay, MA.
•
•'prom reference 55. Sample was from forest soil remote from
industry and human habitation.
jj
From reference 56. Sample was from urban soil. B(a)P concentra-
tions in.contaminated soil near an oil refinery have been observed as high
as 220,000 ng/g soil.
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of POM compounds in most emissions from these sources is small, e.g.,
typically 1% of the total hydrocarbon content. However, some of the
t
POMs in this fraction are POM compounds which laboratory bioassays have
proved to be carcinogenic.
In addition to exposure to airborne POM, ingestion of water and
food also contribute to the total body burden of POM. Estimates of the
relative contributions of air, water, and food to the total body burden
illustrate that food contributes the overwhelming exposure route (see
Table 3). Because the digestive system presents different receptor
organs for POM, the risk to health from POM ingestion cannot be compared
directly to inhalation of POM.
Health Effects of POM
Epidemiology studies have conclusively demonstrated that long-term
occupational exposure to coking and other processes where products of
high temperature coal conversion processes are present, results in in-
creased risk to certain types of cancer (47). Because POMs are present
in the process and effluent streams of these high temperature coal
conversion process, and because many POMs, in pure form, are very potent
carcinogens in laboratory animal studies, POMs are suspected to be
significant co-factors in the causation of these occupational cancers.
Health assessment of environmental POM is complicated by uncertain-
ties in extrapolating dose-response information from pure compound
animal bioassay tests to human exposure to the complex environmental
pollutant mixture. Epidemiology studies are confounded by the con-
current presence of a wide spectrum of non-POM compounds, some of which
may be equally or more hazardous than POM (46). However, epidemiology
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XI
TABLE 3. ESTIMATED DAILY EXPOSURE TO B(a)P, CARCINOGENIC PAH, AND
TOTAL PAH'
a,b
•
Source
Water
Food
Air
TOTAL
Estimated
Exposure, yg/day
B(a)P Carcinogenic PAH°
0.0011 0
1.1 4
0.005 0
1.1 4
.0042
.2
.027
.2
Total PAHd
0.027
27.
0.11
27.
From reference 53.
PAH = Polynuclear Aromatic Hydrocarbons, a major subset of POM.
"Carcinogenic PAH" here refers to the sum of B(a)P, benzo(j)-
fluoranthene, and indeno[l,2,3-cd]pyrene and is acknowledged to repre-
sent only a partial list of actual carcinogenic PAH.
"Total PAH" is the sum of individual PAHs which were measured.
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studies have demonstrated that populations exposed to polluted air,
e.g., in urban areas, are in an increased risk category for lung cancer.
i
Because levels of B(a)P and presumably total POM parallel indices of
general air pollution, and because many POM compounds are carcinogenic
in laboratory bioassays, POM in community air is suspected as a cofactor
which contributes to the excess risk to lung cancer for urban residents.
RECOMMENDATIONS
Implementation of the following recommendations will support a more
complete environmental assessment for polycyclic organic matter, as was
mandated in Section 122 of the Clean Air Act Amendments. Although it
is unlikely that the issue of "whether or not ... (POM) ... may reason-
ably be anticipated to endanger public health" will be resolved with
certainty in the near future, information derived from carrying out the
following recommendations will greatly reduce the risk that an incorrect
decision will be made. Additionally, this information would support the
development of POM control strategies if that course of'action became
necessary.
Recommendations for the Short-Term (one to five years)
1. It is recommended that EPA develop and promote the use of a
standardized procedure for total POM. Although total POM includes both
the hazardous and non-hazardous POM compounds, preliminary statistical
calculations indicate that this total can represent an improved indi-
cator of the integrated hazard of a particular effluent stream of am-
bient air samples (57). That is, a measurement for total POM can cor-
relate better with the POM associated hazard than the previous indicators,
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B(a)P and BSD. Several semiquantitative measurement techniques for
total POM exist; these are the sensitized fluorescence test (37) and the
gravimetric determination of material in one or several adjacent liquid
chromatography (LC) fractions (e.g., Level I, LC fractions 3 and 4)
which contain most of the POM compounds (52). Either of these tech-
niques, as it exists or modified, could provide the basis for a stand-
ardized procedure for total POM. Further, the combined use of total POM
and the previously used indicators would increase the reliability of the
estimate of hazard even more. Statistical techniques should also be
developed to determine the best such joint use of all available indi-
cators including total POM.
2. It is recommended that EPA evaluate the impact of residential
coal burning on ambient air quality, particularly ambient air levels of
total POM. Although coal currently supplies only about two percent of
the total space heating energy in the residential and commercial sec-
tors, the combustion of coal in inefficient residential stoves and
furnaces can be expected to contribute significant amounts of POM to
community air (27, 29, 38, 50, 51). There is renewed interest in resi-
dential coal-fired equipment in certain parts of the country; e.g., the
mountains and west-north central regions where this use of coal is
becoming economically competitive with alternate residential energy
sources (51). Airborne emissions from residential coal burning are
uncontrolled, relatively rich in hazardous organics such as POMs, and
emitted at close to ground level. Consequently, any increase in the
usage of residential coal combustion for space heating, particularly in
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XIV
densely populated areas, could lead to exposure levels of ROMs, which
could be hazardous (50).
t
3. It is recommended that sampling and analysis for total POM
become an integrated component for all emission assessment projects
involving pyrolitic or combustion processes. The objective is to iden-
tify and quantify the major sources of POM in a systematic manner.
Development of such an improved source inventory for POM is important
for negating (or establishing) relationships between emissions of POM
and community health. Because current emissions data for POM is focused
on relatively few large industrial or utility point sources, the con-
tribution of many dispersed area sources may be underestimated. This is
particularly true for POM emissions, where the "large" point sources
tend to be efficiently operated fossil fuel combustors that emit rela-
tively few POMs per unit of heat input, and the small, but multiple and
dispersed area sources tend to be less efficient combustors and conse-
quently emit more POM per unit of heat input.
4. It is recommended that EPA expand its ambient air monitoring
program to include the sampling and analysis of total POM. Quarterly
composite samples of benzo(a)pyrene [B(a)P] are already analyzed for at
approximately 40 sites, but the level of B(a)P alone is not a sufficient
indicator of either total POM or the hazard associated with POM.
Assuming that a standardized procedure for total POM is developed as
recommended in subparagraph 1 above, then it is recommended that this
procedure be implemented at each of the 40 National Air Surveillance
Network (NASN) monitoring sites where B(a)P is currently being
monitored.
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Recommendations for the Long-Term (five to twenty-five years)
1. It is recommended that EPA support a fundamental study of the
formation -of POMs in combustion systems as a function of fuel parameters
and combustion operating conditions. This knowledge would support the
development of improved source emissions inventories and additionally
would provide a data base which would support the development of POM
control technologies.
2. It is recommended that EPA continue and expand research pro-
grams directed at tracking the chemical fate of POMs from the points of
emissions through the transporting media to the eventual receptor. The
goal of these transport and transformation studies is to relate ambient
levels of POM to specific sources of POM. POM sampled from a flue gas
at 400 F may not have the same compositional profile as the ambient POM
resulting from the same source. Individual POM species may degrade,
e.g.* by photo-oxidation, between the flue and the receptor. Because
the relative toxicity of any POM derivative can be very sensitive to
even minor chemical changes, it is as important to characterize the
transformation products as well as the parent POM itself.
3. It is recommended that all coal conversion processes be thor-
oughly evaluated as potential sources of polycyclic organic matter.
Evaluation of these sources should include the monitoring of both point
and fugitive emission streams for total POM. The existing data base
suggests that coal conversion processes involving high temperatures
represent the potentially most potent sources of hazardous POMs (26, 46,
47).
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XVI
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the valuable discussions with
Dr. W. G.-Tucker, SSS/IERL, and Mr. J. A. McSorley, SSS/IERL, in devel-
oping the objectives, scope and approach to this project.
Advice and assistance in obtaining information sources was help-
fully provided by Mr. J. A. Manning, OAQPS, and Dr. R. M. Bruce, Envir-
onmental Criteria and Assessment Office.
We also appreciate the constructive review comments of Mr. G. L.
Johnson, SSS/IERL, and Mr. W. W. Whelan, TIS/IERL.
Finally, we gratefully acknowledge the assistance of Mrs. S. Milton
in assembling the many draft copies and final draft.
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INTRODUCTION
Background
•
The Clean Air Act Amendments of 1977 add Section 122, "Listing of
Certain Unregulated Pollutants," to Title I of The Clean Air Act (1).
This amendment directs the Administrator to "...review all available
relevant information and determine whether or not emissions of ...
polycyclic organic matter into the ambient air will cause, or contribute
to, air pollution which may reasonably be anticipated to endanger public
health." If an affirmative determination results from this review, it
is required that polycyclic organic matter (POM) be added to the list of
pollutants under section 108 (a)(l), "Air Quality Criteria and Control
Techniques," or 112(b)(1)(A), "National Emissions Standards for Hazard-
ous Air Pollutants." Additionally or alternatively, specific categories
of sources of POM could be included in the list published under section
lll(b) (1)(A), "Standards of Performance of New Stationary Sources."
The regulatory impact of any of the above actions would prompt
research, development, and demonstration of POM control systems. The
consequences of exercising any of the aforesaid regulatory actions on
the basis of the "available information" are examined in this report.
Definition of POM
Strictly speaking, any carbon containing compound with two or more
ring structures could be considered polycyclic organic matter. Because
this definition of POM represents such an extraordinary range of com-
pounds, a more limiting definition is necessary. In this report poly-
cyclic organic matter (POM) is defined to be the generic class of
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multiple ring, aromatic compounds which have condensed rings.. The ring
structures may contain heteroatoms (e.g., nitrogen, sulfur, oxygen)
•
and/or have attached substituent groups (e.g., methyl, ethyl, nitrate,
cyano). The term polynuclear aromatic hydrocarbons (PAH) is more res-
trictive and refers to that subset of POMs which consists of condensed
ring aromatics containing only carbon and hydrogen atoms. The above
definitions are consistent with those used in earlier reviews of POM
information (1, 2).
The usage of some POM compounds is entrenched in our everyday
lifestyle and society. For example, many consumer goods (e.g., cos-
metics, dyes, and foods) contain natural and/or synthetic POMs. Cig-
arette smoke is known to contain many POM compounds. Some POM compounds
are valuable pharmaceuticals such as diazepam (a relaxant), acriflav-
inium chloride (an antibiotic), reserpine (an anti-hypertensive), and
many anti-tumor agents. The POM class also includes many biochemicals
that perform an essential role in controlling human life processes,
including mental health.
POM compounds occur in trace quantities in effluent streams of
combustion or pyrolysis processes. They are widely distributed in the
environment. The ubiquity of POMs in plant life suggests that bio-
synthesis is also a possible origin of POMs, but available data indicate
that this is not a major source of POM (6, 7).
Overview of Report
The purpose of this report is to review and analyze the current
data base for environmental assessment of POMs, as mandated in the Clean
Air Act-Amendments of 1977. An adequate data base is requisite not only
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for environmental assessment but also for control strategy development,
if it is determined that POM is reasonably anticipated to endanger
f
public health.
The following elements of the data base are important to environ-
mental assessment of POMs and potential control strategy development:
1. Fundamental chemical and physical properties of POMs.
2. Sources of POM.
3. Ambient concentrations and chemical fate of POMs in air, water, and
soil.
Data on the health effects of POM have recently been reviewed by
the Syracuse Research Corporation (4). It is not intended that this
report focus on the health effects issue. However, several current
issues and questions relative to the health effects of POMs are dis-
cussed.
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OBJECTIVES AND SCOPE
The overall goal of this study is an independent review and anal-
ysis of available POM data with a broad view of present and probable
future emission sources, environmental fate, and potential health
*
effects. Furthermore, EPA's Office of Research and Development, par-
ticularly its Industrial Environmental Research Laboratories (one at
Research Triangle Park, NC; the other in Cincinnati, OH), must be pre-
pared to coordinate and support the development of POM control strategies,
if POMs are recognized as a public health hazard. The main issues to be
addressed in the review and analysis of the POM data base are:
1. -Has all available information been identified by the independent
contractors who were commissioned to review the literature; viz.,
Syracuse Research Corporation (4), Energy and Environmental Anal-
ysis, Inc. (3), and the Research Triangle Institute (6)? If yes,
is this information base sufficient to assess public health hazard
of POMs? What are the most serious gaps in the data base? What
factors limit the credibility of the available information?
2. Is the existing data bank on fundamental chemical and physical
properties of POMs adequate to support environmental assessment,
regulation, and control of POMs? If not, where do we need to focus
present and future research? For example, what fraction of POMs
can be expected in the vapor phase at ordinary ambient temper-
atures? What adsorption characteristics describe the interaction
of POMs with airborne carbonaceous and inorganic particles? What
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are the solubilities of various POMs in water? What are the struc-
tures and stabilities of POMs and their chemical derivatives?
•
3. What.is the accuracy and completeness of the source inventories of
POMs (3, 6)? Have the recent reviews (3, 4, 6) addressed probable
future sources such as coal conversion processes in addition to
past and present sources?
To what extent can environmental scientists correlate source emis-
sion profiles of POMs with chemical profiles of ambient samples?
What is the state of the environmental material balance for POMs;
i.e., are POMs being produced and accumulated at a rate faster than
their removal? For example, does the decrease noted in ambient
urban B(a)P concentrations in the Syracuse Research Corporation
report (4) take into account the total environmental balance of
B(a)P? Or does it reflect a shift in the distribution of B(a)P
from the atmosphere to the land and water? Has B(a)P decreased
while other POMs remained constant or increased?
4. What is extent and quality of ambient multimedia monitoring data?
Has the fate of emissions been sufficiently addressed? Do we
understand the dynamics of the "POM cycle?"
4.1 What is our knowledge of dispersion and distribution of POM
materials?
4.2 What is the persistence of POM in different media?
4.3 What is known of the chemical transformations (e.g., degra-
dation via biological systems, and photochemical degradation
of POMs)?
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4.4 What are the limitations of collection and analytical meth-
odologies?
t • .
5. What'do we know about the public health and ecological hazards of
POMs?
5.1 What differentiates between a toxic profile of POMs and a
benign mixture? Are "young POMs" more toxic than "old POMs?"
What are the potential health effects of the intermediate
derivatives? How does the adsorption of POMs on carbonaceous
particles affect the biological activity of POMs?
5.2 What are the implications of synergistic and antagonistic
health effects of various POM compounds? For example, how
significant is the phenomenon of co-carcinogenesis of POM with
other widespread environmental agents, such as S0_ and NO ?
What are the probable consequences of POMs acting as metal
binding ligands for heavy metals (.e.g., as cadmium, mercury,
and lead) to form biochemically significant POM-metallocenes?
5.3 Does the evidence for POM effects on enzymatic bioreactions
implicate a broader range of health effects? What evidence
exists for health effects other than cancer?
The above framework of questions was formulated as a guide to our
review and analysis of available information on POMs. There exists an
abundance of data on POM, but for the purpose of environmental assess-
ment, these data are often insufficient or not directly applicable for
engineering estimates of human exposure to POM or for evaluation of the
human health effects of POM.
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REVIEW AND ANALYSIS
Available*Information
y
Essentially all readily accessible information (i.e., data which
had been published) has been reviewed in the 1972 NAS report (1), the
1978 EEA report (3), the 1978 SRC report (4), or the 1978 RTI report
(6). The NAS report was the first comprehensive review of POMs which
attempted to interpret and evaluate the increasing amount of data on
their carcinogenic effects. The EEA report, a preliminary assessment of
the major sources of B(a)P, relies heavily on the 1967 study by Hangebrauck
(8). The SRC report, a health-assessment document, includes a com-
prehensive review of the recent experimental studies of the mutagenic
and carcinogenic effects of POMs. The RTI report emphasizes the multi-
media aspect of the POM problem. Other notable information sources on
POMs include the IARC monographs on POMs (9), proceedings of recent
Battelle symposiums on PAHs (10, 11), and the Information Overview.on
Coal Conversion Technologies (12).
The different perspective of recent information searches on POMs
have helped to insure a more complete retrieval of relevant information
from existing literature. The EEA report identifies about 15 major
emission sources and estimates possible exposures that these sources may
present. As a compendium of quantitative information on B(a)P emis-
sions, the EEA report is limited by uncertainties in previous meas-
urements of B(a)P and in subjective estimates of natural emissions. EEA
recognizes that many potentially important sources have not been studied
(e.g., fugitive emissions from industrial sources and small internal
combustion engines). The probability that exposures from unknown sources
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exist at significant levels either continuously or intermittently sug-
gests that POMs cannot be dismissed as a potential health risk.
•
Available source information needs further study, quantification,
and differentiation before any "best available control technology"
(BACT) can be sought, even conceptually. In particular, a more precise
discrimination needs to be made between the relative contributions of
the controllable anthropogenic sources. The hypothesis that anthro-
pogenic combustion is a primary source of POMs needs further study so
that contributions from this source can be compared with those deriving
from natural or uncontrolled sources.
The SRC report (4) was mainly, but not exclusively, dedicated to
characterization of the biological activity of pure POM compounds,
namely the PAHs. SRC classified the compounds in terms of their res-
pective carcinogenic potency as determined principally by animal test-
ing. From this point of view, the study was relatively thorough.
Unfortunately, because PAH-induced cancer was the focus, the study may
have been narrow, as was the NAS study (1), in terms of potential over-
all health effects. Stemmer (13) has suggested that the consequence of
the metal ligand capability of some benign PAHs can be expected to
affect enzymatic mechanisms of life processes. Chronic cardiovascular
disease and emphysema are examples of these. Hence, improved chemical
and bioassay characterization of the various mixtures of POM compounds
is a prerequisite to an improved health assessment for POMs. This type
of data remains as a major unsolved problem of POM health effects research.
Another view of the information search, the RTI search (6), began
with an indexing of chemical POM compounds not necessarily limited to
the usual potential carcinogens. Compounds were tracked to their
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potential sources, to quantify potential exposure from these sources. .
Much of this information resulted from health research with a goal of
t
occupational safety and health. RTI's approach identified information
missed by the other searches. For example, the widespread occurrence
and biomagnification of POMs via the food chain was uncovered as a
distinct possibility. An abundance of European literature on the occur-
rence of POMs in food (particularly barbecued, smoked, and fried foods)
was also reviewed in detail by the RTI group.
The information searchs have been comprehensive, but not exhaus-
tive. The incomplete overlap of findings by the above groups, each
approaching from A different direction, indicates that, if another point
of view search were initiated, further contributions would supplement
the present lists of cited POM studies. Examples of this would be a
search to identify all available information on the occurrence of POMs
in vegetable foods, or a review of the world's literature on POMs in
mycotoxins (14). However, literature searches on POMs are coming to the
point of diminishing returns, particularly as they apply to developing
an improved source inventory and subsequent control systems strategy.
Major gaps in existing research data can now be identified; these areas
need attention in order to refine the characterization of emissions
sources, the chemical nature of the emissions, and (to a more limited
extent) the fate of the emissions insofar as this fate relates to reas-
onable predictions of exposure hazards. Development of this data will
optimize the benefits of future control system programs.
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Chemical and Physical Properties of POMs
A comprehensive data base on chemical and physical properties of
•
POMs is needed before a thorough environmental assessment can be com-
pleted. Key questions that depend on this type of data are:
1. What are the relative amounts of POM compounds in the vapor
phase, condensed phase, and adsorbed phase? How does this distribution
change with temperature? Can this distribution be described not only
for ambient POM, but also for combustion flue gases?
2. What are the solubilities of the various POMs, particularly in
potable waters?
3. What are the molecular parameters that differentiate mutagenic
or toxic POMs from biologically unreactive POMs?
Although information relative to each of these questions exists, in
many cases the data are for pure compounds, and not complex mixtures
such as exist in environmental samples of POM. Thus, the major problem
is in extrapolating data obtained under highly controlled experimental
conditions to the complex situations encountered where a multitude of
POMs coexist in air, water, or soil with many other organic and in-
organic species.
The question of distribution of POMs between vapor, condensed and
adsorbed phases has been studied both experimentally by Murray et al.,
(15) and theoretically by Natusch (17). Important factors in this
distribution are: (1) the equilibrium vapor pressure of the individual
POMs over the condensed phase and over the adsorbed phase, (2) the
kinetics of adsorbtion/condensation, and (3) the temperature. Pupp et_
al. (16) have reported the equilibrium vapor concentrations (EVC) of
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-11-
several representative ROMs. Except for the highest molecular weight .
POMs, they concluded that, at normal ambient temperatures, the EVC was
•
equal to 'or greater than the concentrations of POMs commonly found in
air. Therefore, in theory pure POM compounds could exist in the vapor
phase at gross concentrations significantly higher than typical measured
ambient air levels. Because POMs are typically observed in "partic-
ulate" form (1) instead of the vapor phase, it is likely that adsorption
onto co-existing particles in combustion effluents occurs. The de-
pressive effect of adsorption on the equilibrium vapor pressure and
hence the EVC is known to exist, but a quantitative description of this
effect has not been reported. This type of missing data is essential to
resolving the question of relative distribution between phases. Without
this knowledge, we cannot determine, even with accurate ambient meas-
urements of total POM, if POMs are adsorbing onto particles or if ad-
sorbed POMs are being stripped off into the unsaturated atmosphere.
At the elevated temperatures encountered in the stacks of fossil
fuel burning plants, most or all of the POMs are expected to exist in
the vapor phase. Although the theoretical analysis of Natusch (17)
predicts "PAH vapors present in the stack system of a coal fired power
plant will be rapidly and quantitatively adsorbed onto the surfaces of
co-entrained fly ash particles at, or close to, the stack exit," these
vapors may be so dispersed that much of the emanating PAH remains in the
vapor phase. An improved understanding of these factors is a prereq-
uisite to exposure modelling and to the efficient design of any "add-on"
control device for POMs.
Information on the solubility of POMs in water is important in
understanding their impact on aquatic biota and also in determining
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their potential for transport to humans via drinking water. The data
for POM solubilities in water are probably adequate for application to
•
the above'problems (18, 19, 20). Furthermore, Makay and Shiu (18) have
reported a method of estimating the solubility of a POM based on mol-
ecular structure.
Although the aqueous solubilities of POMs are quite low, primarily
much less than 100 yg/L at 25 C, Andelman and Suess (7) point out that
POMs may be solubilized in much greater quantities by the presence of
surfactants or that they may adsorb to a wide variety of colloidal
material or biota which are abundant in most natural waters. This
phenomenon increases the likelihoood of POM exposure to humans and all
other lifeforms which depend on water for their viability.
The correlation of molecular structure with biological effects is a
goal that extends beyond POMs (21, 22). For POMs, some progress has
been made by investigators such as Lehr et_ al. (23) and Hecht et^ al.
(24) in correlating qualitative structural parameters with mutagenic
activity. Quantitative structure-activity relationships such as those
of Wishnok and Archer for nitrosamines (22) have not, as yet, been
attempted for POMs. A summary of the relation of some basic physico-
chemical properties of POMs to carcinogenesis is given in Table 4 (25).
An improved understanding of the cause and effect relation between
bioreactiyity and chemical properties eases the problem of comprehen-
sively evaluating the biological activity of each POM compound.
Sources of POM
It is generally agreed that incomplete combustion accounts for the
majority of airborne POM emissions (1-6, 8-12, 26-28). Because a
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-13-
TABLE 4. SUMMARY OF PHYSICO-CHEMICAL PROPERTIES OF POLYCYCLIC AROMATIC
HYDROCARBONS AND THEIR RELEVANCE TO CARCINOGENESIS (from
reference 25)
Property
Molecule Size
Thickness
Planarity
Conjugation
Symmetry
Substituents
Remarks
optimum planar area for PAH carcinogens
Very large PAH are not carcinogenic. There
seems to be a limit to the size of a molecule beyond
which it cannot induce cancer.
Apparent
* 120% .
This has been studied in more detail with hetero-
cyclic compounds, but there seems to be a limit to
the thickness of a molecule for proper "fit."
PAH carcinogens are planar. Deviations from plan-
arity reduce carcinogenicity.
Reduction (by partial hydrogenation) of the maxi-
mum number of cumulative double bonds in a PAH
structure reduces carcinogenicity.
Carcinogenic activity may be more frequent in com-
pounds with asymmetric geometry. Exceptions exist.
Size and position of substituents modify
carcinogenicity.
Molecular Weight Most carcinogens have molecular weights below 500.
Volatility
Solubility in
Water
Fluorescence
Photodynamics
PAH hydrocarbons may be sublimed. Important in
transport of particles in the atmosphere.
PAH (carcinogenic and non-carcinogenic) in lipids
varies. As membranes of cells contain lipids, it
may be important in transport of molecules or by
virtue of interaction with membrane.
Many PAH carcinogens exhibit fluorescence. Not
specific.
Many PAH exhibit photodynamic activity. Not
specific.
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-14-
significant portion of airborne POM is associated with suspended parti-
cles, transport Of POM to water and soil via atmospheric deposition can
•
be expected (1, 6, 28). Table 1 illustrates the range of reported
emission factors.
Emission factors for major sources of atmospheric B(a)P have been
estimated and compiled in the recent EEA report (3). It is acknowledged
by EEA and by most reviewers of the EEA report that these estimated
emission factors may have error bounds which span two orders of mag-
nitude. This uncertainty can be directly attributed to: (1) the normal
variation of fractional POM in a combustion effluent--i.e., the pro-
portion of POM in the effluent is extremely dependent on the combustion
parameters, (2) variation in the ratio of B(a)P to total POM, (3) exper-
imental errors associated with collection and analytical methodologies,
and (4) the paucity of quantitative data on either B(a)P or total POM
emissions from individual sources. It is probable that the data base on
POM emission factors will improve significantly in the next 1-5 years;
e.g., as evidenced by the series of Source Assessment Documents cur-
rently being developed by the EPA Industrial Environmental Research
Laboratory at RTP (33).
A major difficulty in the development of a working "source inven-
tory" for POMs is the difficulty in differentiating between the relative
contributions of industrial point sources (e.g., petroleum catalytic
cracking, coal-fired power boilers) and fugitive area-wide sources
(e.g., residential furnaces, automobiles, open burning sources). For
example, open burning includes forest fires—both wildfires and pre-
scribed burns, agricultural burning, peat burning, and burning coal
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refuse banks. The wide range of combustion conditions for these sources,
and the paucity of relevant laboratory and field data contribute to the
"several order of magnitude" uncertainty in the estimated emission
factors. Additionally, the lack of knowledge of fuel loading; e.g.,
total acres burned, contributes further to the uncertainties in total
POM emissions from these sources.
Open burning sources probably contribute a very significant portion
of total POM emissions (1, 3), but the temporal and spatial relation-
ships of these sources to human receptors diminishes their probable
impact on public health. The quality and quantity of existing data do
not permit an accurate assessment of this effect. In addition to the
benefits of dispersion and subsequent dilution of POMs emitted from open
burning, the delayed atmospheric residence between source and receptor
favors increased photo-oxidative degradation of POMs (28). Although
probably beneficial, complete understanding of this effect is clouded by
recent theories that implicate the diol epoxide derivatives of POMs as
the functional agents in POM-induced mutagenesis (4, 10, 11). The diol
epoxides are known to be metabolic derivatives of the parent POM, but it
is reasonable to expect that these and other similar derivatives may
occur as intermediate products of photo-oxidation.
Formation of POMs during combustion processes depends on a number
of combus.tion parameters; e.g., fuel type, fuel to air ratio, temperature-
time relationship of the reaction mixture, and the catalytic properties
of coexisting reaction components. POM compounds within the total mix
are highly dependent on these factors. In general, the amount of B(a)P
from combustion of oil, wood, or natural gas is less than the amount of
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-16-
B(a)P emitted from combustion of an equivalent (in terms of Btu input)
amount of coal (8, 27). It is expected that this ranking would remain
the same for total POM emissions under similar combustion conditions;
and, with the exception of natural gas, this has been confirmed exper-
imentally by Lee, et_ aJL (27). In terms of the size of the combustor,
it is thought that emissions of B(a)P (and presumably total POM) in mass
per unit heat input are inversely related to the gross heat input to the
combustor (8). That is, POM emissions per unit heat input can be
expected to decline as the size of the combustor increases. This is
probably related to the fact that increased temperature and a longer
residence time in the combustion zone favor a decrease in POM emissions
(8, 9, 26). Increased excess air usually tends to lower POM emissions
(29), but because this factor also decreases the average flame temper-
ature, too much excess air may be counterproductive.
The compositional distribution of specific POM compounds resulting
from a combustion source is also very dependent on the combustion par-
ameters. Lee j3t_ al. have described the distribution of POM compounds
resulting from the combustion of three common fuels: coal, wood, and
kerosene (27). Examination of the capillary-column gas chromatograms in
Appendix A illustrates the diversity of POM compounds in various com-
bustion effluents. By constructing and studying alkyl homolog plots of
these POM mixtures and comparing the plots with those obtained from
analysis of POMs in ambient air particles, Lee et al. were able to
correlate: (1) distributions of coal-soot POMs with POMs in ambient air
particles from Indianapolis, and (2) distributions of kerosene-soot POMs
with POMs in ambient air particles from Boston (27). This is signifi-
cant because coal is a primary heating fuel in Indianapolis, and
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-17-
heating is primarily by kerosene and other petroleum based fuels in
Boston. More studies of this type are needed to help clarify the rela-
•
tive contributions of specific energy sources to the total POM emission
inventory. This is particularly important to assignment of priorities
for research and development of control system strategies.
By analyzing the EEA (3) estimates of B(a)P emissions from major
sources, it can be concluded that even a complete elimination of B(a)P
emissions from major industrial point sources may not achieve any sign-
ificant reduction in the total level of POM emitted. That is, when one
considers the uncertainties in the EEA estimates, it is plausible that
B(a)P emissions from area-wide, fugitive type sources; e.g., residential
fireplaces, forest fires, coal refuse banks, and coal-fired residential
furnaces (maximum estimate = 1300 Mg/yr) may constitute greater than
2000 times the B(a)P being emitted from well defined industrial point
sources; e.g., coke ovens, coal-fired power plants and oil-fired in-
dustrial boilers (minimum estimate = .59 Mg/yr). However, this un-
certainty should not deter efforts to control and reduce B(a)P and other
POM emissions from those sources where epidemiological and clinical
evidence indicate that emissions of such compounds "may reasonably be
anticipated to endanger public health."
Ambient Concentration of POM
From the review of available information on ambient concentration
data for POMs, we conclude that POMs are ubiquitous at finite levels in
air, water, and soil (6). Appendix B illustrates the wide range of
ambient concentrations reported for POMs and B(a)P. In addition to the
normal spatial and temporal variations expected with ambient monitoring
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-18-
of specific pollutant species, the range of ambient concentrations
reported for POMs is further increased as a result of inconsistent
•
sampling and analytical techniques (6). That is, different invest-
igators have used different sampling and analytical methods; and each
sampling method has characteristic limitations in collection efficiency
and sample representativeness. Both the SRC report (4) and the EEA
report (3) have briefly reviewed how these factors contribute to ex-
perimental errors in sampling and analysis of B(a)P. A more complete
review of the state-of-the-art in analytical methodology and stationary
source sampling methodology for POMs has been published by Jones et al.
(34) .
The notoriety of B(a)P may be an inadvertant consequence of the
development and popularity of a few select analytical methodologies that
are preferentially more effective in detecting and quantifying this par-
ticular POM. Improved methodology to capture and quantify other POM
compounds is presently being developed (43). This is a prerequisite for
advancement of an adequate POM monitoring program. The state-of-the-art
is such that even what may be technically achieved in principle is not
practical; the effort is too great and the cost is prohibitive. For
example, detection of even well characterized PAHs at levels below
1 ng/m in ambient air strains the limits of even the most advanced gas
chromatography/mass spectroscopy system (34) . Because such instru-
mentation and associated technical support is very expensive, widespread
surveillance of multimedia ambient levels of individual POM compounds at
the currently achievable levels of detection would be prohibitively
costly. A promising semi-quantitative spot test for presence of POMs,
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-19-
which was recently developed (37), could simplify identification of
sources and evaluation of the performance of any BACT for point sources
*
suspected'of being major emitters of POMs. In addition to the present
limitations of the sampling and analytical methodologies, the chemical
reactivity of POMs in ambient media further complicates the analysis of
ambient POM data.
The chemical fate of POMs in air is complex, but the formation of
their epoxide and diol derivatives via photochemical oxidation is thought
to be a step in the process leading to mutagenesis (4, 9-11). Although
evidence points to a lesser chemical stability of POM in air than in
aqueous suspensions, sediments, or soils (28), aerosols containing B(a)P
can survive long enough to travel 100 kilometers or farther from com-
bustion emission sources (35). B(a)P and many other POMs are photo-
chemically unstable as vapors, but their stability is greater when
adsorbed on carbonaceous particles (soot) (41). It is not known if
reactions between POM and other atmospheric constituents (e.g., SO ,
NO , ozone, and 0 ) affect the risk to public health. Chemically,
A £•
electrophilics (e.g., S0_ and NO ) should promote the efficiency of POM
^ J\
degradation and eventual sedimentary removal. Purifying the air of
these electrophilics may have the tendency to stabilize POM aerosols.
The particle size distribution of POM aerosols is concentrated in
the submicron range where washout by natural precipitation and col-
lection by particle control devices at the source are minimal (36),
particularly in the absence of coagulants such as electrolyte mists.
The reaction of POMs with airborne electrolytic species would enhance
the "wet removal" processes of POM from the atmosphere. The "wet
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-20-
removal" processes consist of capture by cloud droplets and the scrub-
bing effect of rain; and because of the enormous quantity of water which
cycles in*the atmosphere, these processes are responsible for the bulk
of the removal of airborne particles (44). The magnitude of the above
covariant effects has not been determined. These dynamics of the POM-
environment reaction matrix add to the complexity of interpreting am-
bient concentration data for ROMs.
Care must be taken not to trade-off air emissions for disposal as
solid wastes. For example, removal and collection of POMs from sta-
tionary combustion source effluent streams could create a serious soil
and wastewater contamination problem. Soils could be contaminated by
accumulations in biota or in leachates which contaminate aqueous sedi-
ment, surface water, and even ground water. POMs have been identified
in each of these media (6, 28). Accumulations of PAHs and their alkyl
homologies persist for centuries, and are stable enough to serve as a
geological index of historical combustion events such as forest fires
and volcanoes (30, 32).
The effects of POM on the normal rate.of decomposition of organic
matter in soil may be important. Trace metals such as zinc and copper
are operative (at low concentrations) to promote and (at excess concen-
trations) to inhibit the degradation of biological materials (42).
Because POMs can act as metal-binding ligands, they may combine with
existing zinc and copper sinks to form stable POM-metallocenes. Thus,
they may reduce the decomposition rate by removing the essential ele-
ments of zinc and copper and stabilize existing organic matter. Fur-
thermore, POMs and POM-metallocenes may act as biocidal agents on other
lower forms of animal life which normally accelerate decomposition.
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-21-
Because all of the above factors may have a marked effect on the
ambient POM data reported, we recommend a critical analysis of the
•
present day collection and analytical methods before proceeding with any
expansion of ambient POM surveillance programs.
Health Effects of POMs
Because POMs have been studied extensively in the role of tumor
initiation and promotion, chemical carcinogenesis has been the focus of
the SRC health assessment of POMs (4). A major conclusion of the SRC
report (4) is that some (but not all) components of the POM mixtures
which are emitted from combustion sources can initiate mutagenic events
by reacting with DNA. A much proposed hypothesis is that the actual
species needed to induce pathological mutagenesis is the diol epoxide of
some PAHs rather than the parent PAH such as B(a)P (23). That this
hypothesis describes all POM/receptor interactions has not been accepted
by most investigators in chemical carcinogenesis (4). Therefore, it is
uncertain if the diol epoxide (or other active chemical derivatives that
occur in ambient air) is the driving agent for a biological response
normally attributed to the parent PAH reactant. Another problem is that
contaminants (such as SOO may affect the character of a reactant
substrate such as human lung tissue. Furthermore, transient active
metabolites have a lifetime which may make them unsuitable for analysis
by present chemical or bioassay techniques.
Generally, particulate POMs which are available for inhalation also
co-exist with metallic pollutants in the particulate phase. Heavy
metals (e.g., thallium, mercury, lead, and bismuth) are usually present
in trace quantities in coal combustion effluent streams (38). It is
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-22-
uncertain if this co-existence with metals deactivates or accelerates
POM in the biological conversion reactions that form the direct car-
•
cinogen. 'Many heavy metals and their oxides may aid in retention, to
provide longer residence time for the POMs in, for example, lung tissue.
Such effects complicate the extrapolation of pure compound bioassay
results to predict the physiological fate of POM captured by any ex-
posure route, whether inhalation, ingestion, or epidermal. The con-
sequences of such phenomena would significantly affect the development
of control systems. For example, using the co-action agent to measure
and control emissions may be more effective than directly attacking the
POMs themselves.
The SRC report points out that disabling toxicity was a significant
cause of mortality that complicated longer-term studies of carcinogenic
potential in sample animals. Often cancer research attempts to cope
with this as a problem rather than appraise it as a direct effect of the
agents involved. Some of the potentially "worse" carcinogens may
require a very toxic resistant species of animal that will survive long
enough to separate the mutagenic phenomenon from other complications.
The toxicity threshold to POMs alone (or in combination with other
inseparable components of both natural and anthropogenic emissions) may
be trivial if ambient air levels are stabilized either chemically or by
physical adsorption on particles; however, they could be severe if high
concentrations of transients occur intermittently. Other suspected
health effects are respiratory diseases such as chronic emphyzema and
asthma (13). Neurophysiological and other behavioral response effects
as noted for exposure to vaporous organic matter (such as from aviation
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-23-
fuel) may also be important (39). Because these effects are primarily
occupational hazards, the definition of "may endanger (public health)"
•
is an issue. Do we apply the sliding scale test of a severe harm (e.g.,
delayed carcinogen) to few vs. a lesser harm (e.g., any adverse behav-
ioral response) to many (40)?
It is not known if extrapolating occupational mortality and mor-
bidity indicators to the population at large is linear. Risk assessment
in these extrapolations is highly speculative, depending in part on the
level of optimism (or pessimism) of the evaluator. Mandating zero
emissions of both POMs and other co-acting species is the only option
for the pessimist. The optimist would quantify concentrations as func-
tions of positions in space and relate these concentrations to proba-
bilities of increasing mortality or morbidity rates compared to a base-
line of clean air. In approaching the problem from the view of BACT,
the pessimist's goal is unachievable; however, the optimist's goal
(accepting some finite deterioration of air quality) has a reasonable
chance of success. Data are insufficient to permit assignments of risks
which are related to exposures by any or all modes of exposure (28);
i.e., inhalation, epidermal and ingestion. Therefore, performance goals
for BACT cannot yet be defined as an achievable target for research,
development, and demonstration.
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CONCLUSIONS
Polycyclic organic matter (POM) is ubiquitous in the environment.
• • ,
Both natural and anthropogenic sources emit a large number (greater than
100) of specific POM compounds. Many of these compounds have been found
to be carcinogenic to animals. At issue is whether emissions of POM
into the ambient air can be reasonably anticipated to endanger public
health. Uncertainties in both POM exposure data and POM health effects
data preclude a conclusive scientific assessment of this issue. How-
ever, existing data do indicate that there exists a potential for a POM
associated public health hazard, and, consequently, this issue cannot be
dismissed.
The following findings have resulted from the review and analysis
of available information on POM.
Measurement of POM
Because POM in the ambient air consists of a large number of spec-
ific polycyclic organic compounds at very low concentrations and co-
exists with a broader spectrum of organic compounds, POM is very dif-
ficult to detect and quantify. Traditionally, the amount of POM has
been identified by measurement of benzo(a)pyrene [B(a)P], which is one
of many POM compounds, or by benzene soluble organics [BSO], which
represents a broader range of organic compounds. Because the relation
of B(a)P or BSO to total POM is variable, both B(a)P and BSO are limited
in their usefulness as reliable indicators of total POM.
Recent improvements in POM sampling and analysis will result in
more efficient capture and characterization of a broader class of POM
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-25-
compounds. Cartridge samplers with absorbent resins can now be used tp
increase sampling efficiency, and gas chromatography coupled with mass
•
spectroscbpy now provides a tool for improved identification of indi-
vidual POM compounds.
Several semiquantitative procedures are available for the estima-
tion of total POM; these are the sensitized fluorescence test for poly-
nuclear aromatic hydrocarbons (37), and the combination of gravimetric
fractions resulting from a liquid chromatography separation (52).
Although these procedures for total POM do not characterize the dis-
tribution of individual POM compounds, total POM can be a better indi-
cator of the integrated amount of hazardous POM compounds than any
individual POM, e.g., B(a)P, or the collective total of organic com-
pounds indicated by benzene soluble organics (BSO).
Sources of POM
The sources of POM are principally, but not exclusively, related to
the incomplete combustion or pyrolysis of fossil fuels and other organic
matter. Burning coal refuse banks, forest fires (both wildfires and
prescribed burning), residential combustion of coal and coke production
are thought to be major sources of POM released to the atmosphere (3).
Estimates of total POM emissions from these sources are very crude, and
consequently, the prediction of human exposure by modeling the dis-
persion of POM from known sources is limited. Table 1 illustrates the
wide ranges of estimates for B(a)P emission factors. Although the open
burning sources contribute a significant portion of total B(a)P emis-
sions, the temporal and spatial relationship of these sources to human
receptors diminishes their probable impact on public health.
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-26-
Coal derived materials (e.g., coal tar, pitch, creosote, and soot)
*
and coal conversion processes (e.g., coking, gasification, and liquifi-
t
cation) are known sources of POM (6, 46, 47). Approximately 300 indi-
vidual POM compounds have been identified as products of coal carboni-
zation (coking) (48), and there are surely many more. Coal itself is
highly aromatic in chemical structure and is known to contain B(a)P and
other POMs (49), but most POMs from coal processes are chemically formed
during high temperature (700° C to 1500° C) pyrosynthetic conversion
reactions.
Coal gasification involves chemical reactions similar to carboni-
zation, and is also a source of POMs. The high boiling condensation
products of coal gasification contain POMs. Coal liquification products
and by-products, shale derived oil, and petroleum crude oil represent
additional energy related materials which contain POM (6, 26). Proper
design, construction, and maintenance of coal processing plants is
necessary to prevent the commercialization of coal and shale conversion
from becoming a new major source of POM.
Ambient Concentrations of POM
Trace levels of POM have been detected in air, water, and soil. In
air, POM is thought to exist primarily in a condensed phase, either
adsorbed onto particulate matter, especially soot, or condensed with
other organic compounds as an aerosol. Because POMs are formed in a
vapor phase during high temperature combustion or pyrolysis processes
and condense or adsorb onto particulate matter, smaller particles, which
have a higher surface area to mass ratio, have a higher concentration of
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-27-
POM per unit mass. These smaller particles are more apt to penetrate
deep into the lung during inhalation. The solubility of POMs in water
•
is very small, and consequently most POM in aquatic systems adsorbs on
particulates and in sediment. Typical levels of benzo(a)pyrene in the
environment are illustrated in Table 2.
Ambient air sampling of B(a)P or total POM is primarily by particu-
late capture on glass fiber filters. The recognized disadvantages of
this method are (1) inability to capture vapor phase POM, (2) chemical
reaction on the filter, and (3) desorption or stripping of POM from
particulate on the filter. All of these problems result in a loss of
detectable POM from the filter, and consequently, the reported values of
ambient concentrations probably underestimate the real situation.
Exposure to POM
Because significant uncertainty exists for POM source inventories
and ambient air concentrations, it is difficult to provide confident
estimates of human exposure to airborne POM. The existing data are
primarily for B(a)P emission factors and ambient B(a)P levels (e.g.,
references 1-3, 6), but the ratio of B(a)P to total POM is known to be
highly variable, ranging at least 1% to 20% (28). However, some ex-
posure estimates have been made for occupational settings. In addition
to cigarette smoking the greatest human exposures to airborne POM prob-
ably occur in certain occupations, viz., the top side of coke ovens,
coal tar pitch working, and hot asphalt paving (45). The total fraction
of POM compounds in most emissions from these sources is small, e.g.,
typically 1% of the total hydrocarbon content. However, some of the
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-28-
POMs in this fraction are POM compounds which laboratory bioassays have •
proved to be carcinogenic.
•
In addition to exposure to airborne POM, ingestion of water and
food also contribute to the total body burden of POM. Estimates of the
relative contributions of air, water, and food to the total body burden
illustrate that food contributes the overwhelming exposure route (see
Table 3). Because the digestive system presents different receptor
organs for POM, the risk to health from POM ingestion cannot be compared
directly to inhalation of POM.
Health Effects of POM
Epidemiology studies have conclusively demonstrated that long-term
occupational exposure to coking and other processes where products of
high temperature coal conversion processes are present, results in in-
creased risk to certain types of cancer (47). Because POMs are present
in the process and effluent streams of these high temperature coal
conversion process, and because many POMs, in pure form, are very potent
carcinogens in laboratory animal studies, POMs are suspected to be
significant co-factors in the causation of these occupational cancers.
Health assessment of environmental POM is complicated by uncertain-
ties in extrapolating dose-response information from pure compound
animal bioassay tests to human exposure to the complex environmental
pollutant mixture. Epidemiology studies are confounded by the con-
current presence of a wide spectrum of non-POM compounds, some of which
may be equally or more hazardous than POM (46). However, epidemiology
studies have demonstrated that populations exposed to polluted air,
e.g., in -urban areas, are in an increased risk category for lung cancer.
-------
-29-
Because levels of B(a)P and presumably total POM parallel indices of
general air pollution, and because many POM compounds are carcinogenic
»
in laboratory bioassays, POM in community air is suspected as a cofactor
which contributes to the excess risk to lung cancer for urban residents.
-------
-30-
RECOMMENDATIONS
•
The .principal recommendation of this report is that the EPA Office
of Research and Development continue to develop an improved data base on
POM source inventories, ambient concentrations of POM, and health effects
of POM mixtures in the environment. The current environmental assess-
ment programs being conducted by the Office of Energy, Minerals and
Industry of EPA/ORD are examples of programs that will provide scien-
tific and engineering data that will support a more conclusive assess-
ment of the risk of ROMs'to public health. Several specific recom-
mendations are set forth below.
Recommendations for the Short-Term (one to five years)
1. It is recommended that EPA develop and promote the use of a
standardized procedure for total POM. Although total POM includes both
the hazardous and non-hazardous POM compounds, preliminary statistical
calculations indicate that this total can represent an improved indi-
cator of the integrated hazard of a particular effluent stream of am-
bient air samples (57). That is, a measurement for total POM can cor-
relate better with the POM associated hazard than the previous indi-
cators, B(a)P and BSD. Several semiquantitative measurement techniques
for total POM exist; these are the sensitized fluorescence test (37) and
the gravimetric determination of material in one or several adjacent
liquid chromatography (LC) fractions (e.g., Level I, LC fractions 3 and
4) which contain most of the POM compounds (52). Either of these tech-
niques, as it exists or modified, could provide the basis for a stand-
ardized procedure for total POM. Further, the combined use of total POM
-------
-31-
and the previously used indicators would increase the reliability of the
i
estimate of hazard even more. Statistical techniques should also be
developed* to determine the best such joint use of all available indi-
cators including total POM.
2. It is recommended that EPA evaluate the impact of residential
coal burning on ambient air quality, particularly ambient air levels of
total POM. Although coal currently supplies only about two percent of
the total space heating energy in the residential and commercial sec-
tors, the combustion of coal in inefficient residential stoves and
furnaces can be expected to contribute significant amounts of POM to
community air (27, 29, 38, 50, 51). There is renewed interest in resi-
dential coal-fired equipment in certain parts of the country; e.g., the
mountains and west-north central regions where this use of coal is
becoming economically competitive with alternate residential energy
sources (51). Airborne emissions from residential coal burning are
uncontrolled, relatively rich in hazardous organics such as POMs, and
emitted at close to ground level. Consequently, any increase in the
usage of residential coal combustion for space heating, particularly in
densely populated areas, could lead to exposure levels of POMs which
could be hazardous (50).
3. It is recommended that sampling and analysis for total POM
become an integrated component for all emission assessment projects
involving pyrolitic or combustion processes. The objective is to iden-
tify and quantify the major sources of POM in a systematic manner.
Development of such an improved source inventory for POM is important
for negating (or establishing) relationships between emissions of POM
-------
-32-
and community health. Because current emissions data for POM is focused
on relatively few large industrial or utility point sources, the con-
t
tributioit of many dispersed area sources may be underestimated. This is
particularly true for POM emissions, where the "large" point sources
tend to be efficiently operated fossil fuel combustors that emit rela-
tively few POMs per unit of heat input, and the small, but multiple and
dispersed area sources tend to be less efficient combustors and con-
sequently emit more POM per unit of heat input.
4. It is recommended that EPA expand its ambient air monitoring
program to include the sampling and analysis of total POM. Quarterly
composite samples of benzo(a)pyrene [B(a)P] are already analyzed for at
approximately 40 sites, but the level of B(a)P alone is not a sufficient
indicator of either total POM or the hazard associated with POM.
Assuming that a standardized procedure for total POM is developed as
recommended in subparagraph 1 above, then it is recommended that this
procedure be implemented at each of the 40 National Air Surveillance
Network (NASN) monitoring sites where B(a)P is currently being monitored.
Recommendations for the Long-Term (five to twenty-five years)
1. It is recommended that EPA support a fundamental study of the
formation of POMs in combustion systems as a function of fuel parameters
and combustion operating conditions. This knowledge would support the
development of improved source emissions inventories and additionally
would provide a data base which would support the development of POM
control technologies.
2. It is recommended that EPA continue and expand research prog-
rams directed at tracking the chemical fate of POMs from the points of
-------
-33-
emissions through the transporting media to the eventual receptor. The
goal of these transport and transformation studies is to relate ambient
levels of 'POM to specific sources of POM. POM sampled from a flue gas
at 400° F may not have the same compositional profile as the ambient POM
resulting from the same source. Individual POM species may degrade,
e.g-> by photo-oxidation, between the flue and the receptor. Because
the relative toxicity of any POM derivative can be very sensitive to
even minor chemical changes, it is as important to characterize the
transformation products as well as the parent POM itself.
3. It is recommended that all coal conversion processes be thor-
oughly evaluated as potential sources of polycyclic organic matter.
Evaluation of these sources should include the monitoring of both point
and fugitive emission streams for total POM. The existing data base
suggests that coal conversion processes involving high temperatures
represent the potentially most potent sources of hazardous POMs (26, 46,
47).
-------
-34-
REFERENCES
1. National Academy of Sciences, Committee on Biological Effects of
Atmospheric Pollutants. Participate Polycyclic Organic Matter.
Washington, DC, 1972.
2. Scientific and Technical Assessment Report on_ Participate Poly-
cyclic Organic Matter (PPOM). U.S. Environmental Protection
Agency, Washington, DC. Publication No. EPA-600/6-75-001. 1975.
3. Energy and Environmental Analysis, Inc., Preliminary Assessment of
the Sources, Control and Population Exposure tp_ Airborne Polycyclic
Organic Matter (POM) as_ Indicated by_ Benzo(a)pyrene [B(a)P]. Nov.
1978.
4. Syracuse Research Corporation. EPA External Review Draft: Health
Assessment Document for Polycyclic Organic Matter. May 1978.
5. Kites, R. A., R. E. LaFlamme, and J. W. Farrington. Sedimentary
Polycyclic Aromatic Hydrocarbons: The Historical Record. Science,
lj)8_:829-831, 1977.
6. Research Triangle Institute. Draft Report: Sources and Ambient
Concentration Data for Polycyclic Organic Matter. June 1978.
7. Andelman, J. B. and M. J. Suess. Polynuclear Aromatic Hydrocarbons
in the Water Environment. Bull. Wld Hlth Org. 43, 479; 1970.
8. Hangebrauck, R. P., D. J. von Lehmden, and J. E. Meeker. Sources
of Polynuclear Hydrocarbons in the Atmosphere. U.S. HEW, Public
Health Service, AP-33, PB-174-706, 1967, Washington, DC.
9. International Agency for Research on Cancer. I ARC Monographs of_
the Evaluation of the Carcinogenic Risks of Chemicals tp_ Man:
Certain Polycyclic Aromatic Hydrocarbons and Heterocyclic Com-
pounds . Vol. 3. World Health Organization. 1973.
10. Freudenthal, R. I., and P. W. Jones (eds.). Carcinogenesis,
Vol. I. Polynuclear Aromatic Hydrocarbons: Chemistry, Metabolism,
and Carcinogenesis, Raven Press, New York, New York. 1976.
11. Jones, P. W., and R. I. Freudenthal (eds.). Carcinogenesis,
Vol. 3: Polynuclear Aromatic Hydrocarbons, Raven Press, New York,
New York. 1978.
12. Braunstein, H. M., E. D. Copenhaver, and H. A. Pfuderer. Envir-
onmental, Health, and Control Aspects of_ Coal Conversion: An
Informational Overview, ORNL/EIA-94 UC-11, -41, -48, -90i, Energy
Research and Development Administration, Assistant Administrator
for Environment and Safety, April 1977, Vol. I and II.
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-35-
13. Stemmer, K. L. Clinical Problems Induced by PAH, in Carcinogenesis,
Vol. I: Polynuclear Aromatic Hydrocarbons: Chemistry, Metabolism
and jCarcinogenesis, Raven Press, New York, New York, 1976.
•
14. Gould, R. F. Mycotoxins and Other Fungal Related Food Problems,
Adv. in Chem. Series 149, ACS, Washington, DC, 1976.
15. Murray, J. J., R. F. Pottie, and C. Pupp. The Vapor Pressures and
Enthalpies of Sublimation of Five Polycyclic Aromatic Hydrocarbons.
Can. .J. Chem., 52(4):557-563, 1974.
16. Pupp, C., R. C. Lao, J. J. Murray, and R. F. Pottie. Equilibrium
Vapor Concentrations of Some Polycyclic Aromatic Hydrocarbons,
Arsenic Trioxide and Selenium Dioxide and the Collection Effic-
iencies of These Air Pollutants. Atmos. Environ., IB_(9): 915-925,
1974.
17. Natusch, D. F. S., and B. A. Tomkins. Theoretical Consideration of
the Adsorption of Polynuclear Aromatic Hydrocarbon Vapor onto Fly
Ash in a Coal-Fired Power Plant. In: Carcinogenesis, Vol. 3,
Polynuclear Aromatic Hydrocarbons. P. W. Jones and R. I. Freudenthal
(eds.). Raven Press, New York, New York, 1978. pp. 145-153.
18. Mackay, D., and W. Y. Shiu. Aqueous Solubilities of Polynuclear
Aromatic Hydrocarbons, J_. Chem. Eng. Data, ^2_(4)399; 1977.
19. May, W. E., and S. P. Wasik. Determination of the Aqueous Solu-
bility of Polynuclear Aromatic Hydrocarbons by a Coupled Column
Liquid Chromatographic Technique. Anal. Chem. 5£(1)175; 1978.
20; Schwarz, F. P. Determination of Temperature Dependence of Solu-
bilities of Polycyclic Aromatic Hydrocarbons in Aqueous Solutions
by a Fluorescence Method. J_. Chem. Eng. Data, 22_(3)273; 1977.
21. Hansch, C. A Quantitative Approach to Biochemical Structure-
Activity Relationships, Ace. Chem. Res., 2_, 232; 1969.
22. Wishnok, J. S., M. C. Archer, A. S. Edelman, and W. M..Rand.
Nitrosamine Carcinogenicity: A Quantitative Hansch-Taft Structure-
Activity Relationship, Chem.-Biol. Interactions, 20, 43; 1978.
23. Lehr, R. E., H. Yagi, D. R. Thakker, W. Levin, A. W. Wood, A. H.
Conney, and D. M. Jerina. The Bay Region Theory of Polycyclic
Aromatic Hydrocarbon-Induced Carcinogenicity. Cafcinogenesis,
Vol. 3: Polynuclear Aromatic Hydrocarbons, Raven Press, New York,
New York, 1978.
24. Hecht, S. S., E. J. LaVoie, and D. Hoffman. Structure-Activity
Relationships in Polynuclear Aromatic Hydrocarbons, Conference on
Carbonaceous Particles in the Atmosphere, Berkeley, California,
March 20-22, 1978.
-------
-36-
25. Multimedia Environmental Goals for Environmental Assessment,
Vol. 1, EPA-600/7-77-136a, pp. G-15.
26. Guerin, M. R. Energy Sources of Polycyclic Aromatic Hydrocarbons.
Oak Ridge National Laboratory (CONF-770130-2), 1978.
27. Lee, M. L., G. P. Prado, J. B. Howard, and R. A. Hites. Source
Identification of Urban Airborne Polycyclic Aromatic Hydrocarbons
by GC/MS and HRMS, Biomed. Mass Spec. £: 182-6; 1977.
28. Suess, M. J. The Environmental Load and Cycle of Polycyclic Aro-
matic Hydrocarbons. The Science of the Total Environment, 6^ 239;
1976.
29. Source Assessment: Coal-Fired Residential Combustion Equipment
Field Tests, June 1977, EPA-600/2-78-004o, U.S. Environmental
Protection Agency, June 1978.
30. Blumer, M. Polycyclic Aromatic Compounds in Nature. Sci. Am.,
234_(3), 35; 1976.
31. Blumer, M., and W. W. Youngblood. Polycyclic Aromatic Hydrocarbons
in Soils and Recent Sediments. Science, 188, 53; 1975.
32. Hites, R. A., R. E. LaFlamme, and J. W. Farrington. Sedimentary
Polycyclic Aromatic Hydrocarbons: The Historical Record. Science,
198, 829; 1977.
33. U.S. EPA, Industrial Environmental Research Laboratory (RTP, NC),
Source Assessment Documents, Contract No. 68-02-1874. For example:
Source Assessment: Coal-Fired Residential Combustion Equipment
Field Tests, June 1977, EPA-600/2-78-004o, June 1978.
34. Jones, P. W., J. E. Wilkinson, and P. E. Strup. Measurement of
Polycyclic Organic Materials and Other Hazardous Organic Compounds
in Stack Gases: State-of-the-Art, EPA-600/2-77-202, October 1977.
35. Lunde, G., and A. Bjorseth. Polycylic Aromatic Hydrocarbons in
Long-Range Transported Aerosols, Nature, 268, 518-519, 1977.
36. National Academy of Sciences. Committee on Medical and Biological
Effects of Environmental Pollutants. Airborne Particles. EPA-600/1-
77-053, November 1977.
37. Sensitized Fluorescence for the Detection of Polycyclic Aromatic
Hydrocarbons, EPA-600/7-78-182, September 1978.
38. Preliminary Emissions Assessment of_ Conventional Stationary
Combustion Systems, Vol. II, Final Report, EPA-600/2-76-046b,
March 1976.
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-37-
39. Knave, B., B. A. Olson, S. Elofson, F. Gamberale, A. Isaksson,
P. Hindus, H. E., Persson, G. Struwe, A. Wennberg, and P. Westerho-lm.
Long Term Exposure to Jet Fuel. Scand. J_. Work Environ. ^ Health.
4:19*45, 1978.
^— »
40. Drechsler, T. Public Health Endangerment and.Standards of Proof:
Ethyl Corp. vs. EPA. Environmental Affairs, VI_(2):227-247, 1977.
41. Fitch, W. L., and D. H. Smith. Analysis of Polymeric Carbon, Con-
ference on Carbonaceous Particles in the Atmosphere, Berkeley,
California, March 20-22, 1978.
42. Tyler, G. Effects of Heavy Metal Pollution on Decomposition in
Forest Soils — III. Statens Naturvardsverk, July 1977, pages
1-105. (English Summary in: Summaries of Foreign Government
Environmental Reports, NTISUB/C/135-012, No. 64, Dec. 1977.
43. EPA/IERL-RTP Interim Procedures for Level 2 Sampling and Analysis
of Organic Materials, EPA-600/7-78-016, February 1978.
44. Esmen, N. A., and M. Corn. Residence Time of Particulates in
Urban Air, Atmos. Env. 5:571-578, 1971.
45. Bridbord, K., et_ a.l_. Human Exposure to Polynuclear Aromatic Hydro-
carbons. Carcinogenesis, Vol. 1, Polynuclear Aromatic Hydrocarbons,
Raven Press, New York, New YOrk, 1976.
46. Komreich, M. R. Coal Conversion Processes: Potential Carcino-
genic Risk, MITRE Technical Report MTR-7155, March 1976.
47. Freudenthal, R. I., et^ aK Carcinogenic Potential of Coal and Coal
Conversion Products, A Battelle Energy Program Report, Battelle
Columbus Laboratories, February 1975.
48. Anderson, H. C., and W. R. K. Wu. Properties of Compounds in Coal
Carbonization Products. U.S. Department of Interior, Bureau of
Mines, Bulletin 606, 1962.
49. Woo, C. S., et^ ajL Polynuclear Aromatic Hydrocarbons in Coal-
Identification by Their X-ray Exited Optical Luminescence. Envir-
onmental Science and Technology, L2(2):173-174, Feb. 1978.
50. Weber, R. C. Impact on Local Air Quality from Coal-Fired Resi-
dential Furnaces. M. S. Thesis, University of North Carolina,
Chapel Hill, NC, 1978.
51. Cart, E. N., et^ aK Evaluation of the Feasibility for Widespread
Introduction of_ Coal into the Residential and Commercial Sectors,
Exxon Research and Engineering Report prepared for the Council on
Environmental Quality, Aug. 1977.
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-38-
52. Combustion Source Assessment Methods and Procedures Manual for
Sampling and Analysis, prepared for EPA Industrial Environmental
Research Laboratory, Research Triangle Park, by TRW, Jan. 1977.
• . •
53. Santodonato, J. et_ aj_. Human Health Effects Section of the Water
Quality Criterion Document for Polynuclear Aromatic Hydrocarbons,
Draft Report prepared for EPA Office of Research and Development by
Syracuse Research Corporation, Oct. 1978.
54. Giger, W., and M. Bluraer. Polycyclic Aromatic Hydrocarbons in the
Environment. Anal. Chem . 46^:1663; 1974.
55. Harrison, R. et_ a_K Polynuclear Aromatic Hydrocarbons in Raw,
Potable and Waste Water. Water Res. . £:331-9; 1975.
56. Shabad, L. M. et^ al . The Carcinogenic Hydrocarbon Benzo(a)pyrene
in the Soil. J_. NJU. Cancer Inst. 7:1179-1191; 1969.
57. Leadbetter, M. R. , and J. 0. Milliken. Assessment of POM Mix-
tures, Unpublished memo to W. G. Tucker, Industrial Environmental
Research Laboratory, U.S. Environmental Protection Agency, Research
Triangle Park, NC, Feb. 20, 1979.
-------
APPENDIX A
CAPILLARY-COLUMN GAS CHROMATOGRAMS
of
POM FRACTIONS FROM COMBUSTION PRODUCTS
(from reference A-l)
CONTENTS
Table A-l POM Identified by Gas Chromatography/Mass
Spectroscopy (from reference A-l). A-l
Figure A-l Capillary-Column Gas Chromatogram of POM
Fraction from Coal Combustion Products. For
compound identification key, see Table A-l from
reference A-l A-2
Figure A-2 Capillary-Column Gas Chromatogram of POM
Fraction from Wood Combustion Products. For
Compound identification key, see Table A-l from
reference A-l A-3
Figure A-3 Capillary-Column Gas Chromatogram of POM
Fraction from Kerosene Combustion Products. For
compound identification key, see Table A-l from
reference A-l A-4
Reference A-5
-------
A-l
TABLE A-l. POM IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROSCOPY
Peak No.
Compound
Peak No.
Compound
1 Me.thylnaphthalene
2 Biphenyl
3 Ethylnaphthalene3
4 Acenaphthylene
5 Methylbiphenyl
6 Dibenzofuran
7 Propylnaphthalene
8 Fluorene
9 Methyldibenzofuran
10 C14Hg (Unknown)
11 Methylfluorene
12 Ethyldibenzofurana
13 Dibenzothiophene
14 Phenanthrene
IS Anthracene
16 Ethylfluorenea
17 Propyldibenzofuran
18 Methylphenanthrenec
19 4H-cyclopenta[def]-
phenanthrene
20 Methyl-4H-cyclopenta-
[def]phenanthrene
o
21 Ethylphenanthrene
22 Fluoranthene
23 Benz[e]acenaphthylene
24 Benzo[def]dibenzothiophene
25 Pyrene
26 Ethyl-4H-cyclopenta[def]-
phenanthrene
27 Methylfluoranthene
28 Benzo [ajfluorene
29 Benzo [bjfluorene
30 Benzo[ghi]fluoranthene
31 C..H-. (Unknown)
lo 1U
32 Cyclopenta[cd]pyrene
33 Benz[£] anthracene
34 Chrysene
35 Methylchrysene6
36 Methyl eyelopenta[c
-------
TEMP (°C»
TIMC (WIN) 0
70
90 110
130
150
170
190
210
230
250
10
20
30
50
60
70
60
110
Figure A-l. Capillary-column gas cliroiiiatojjriiins of POM Fractions from combustion products
(From reference A-l).
-------
WOOD
14
9 10 11
i v. giwii nn ji
LJJLu^JjjkLJJ UMA/wVl
IS IB
18
20
TEMP (CCJ
TIME (MIN) 0
70
90
110
130
150
170
190
210
230
250
10
20
30
40
50
60
70
60
90
110
Figure A-2. Capillary-column gas chromatogram of POM fraction from wood combustion products
compound identification key, see Table A-l from Reference A-l.
l:ov
-------
XCROSCNB
10
uW
10
15
18
22
.125
23
L'J
30
31
32
39
PI
47
E«P CO
IME (MINI 0
70
90
110
130
150
170
190
210
230
250
10
20
30
40
50
60
70
80
90
110
Figure A-3. Capillary-column gas chromato>>rain of POM fraction from kerosene combustion products.
For compound identification key, see Table A-l from reference A-l.
-------
A-5
REFERENCE
A-l Lee,. M. L., G. P. Prado, J. B. Howard, and R. A. Hites. Source
Identification of Urban Airborne Polycyclic Aromatic Hydrocarbons
by GC/MS and HRMS, Biomed. Mass Spec., 4:182-6; 1977.
-------
APPENDIX B
AMBIENT CONCENTRATION DATA FOR POM
FIGURES
Number
B-l Ambient Concentration Data for POM in Rural Air in
yg/m B-l
B-2 Ambient ..Concentration Data for POM in Suburban Air
in pg/m B-2
B-3 Ambient Concentration Data for POM in Urban Air in
yg/nr B-3
B-4 Ambient Concentration Data for Benzo(a)pyrene in Urban
Air in vg/m B-5
B-5 Ambient Concentration Data for Total POM in pg/£ in
Unpolluted Water B-6
B-6 Ambient Concentration Data for POM in River Water in
Vg/t B-7
B-7 Ambient Concentration of Total POM in pg/kg in
Unpolluted Soils B-8
B-8 Ambient Concentrations of Benzo(a)pyrene in Various
Soils in pg/kg B-9
Reference B-10
-------
B-l
Naphthalene
Anthracene!
Phenantfirena
Pyfena
Dibenzo(a.£)anthracen«
Benz(e)pyrene
Benz(a)pyrene;
Benzo{g,h,i)perylene
Coronene
Fluoranthen*
0.00011
0.001 i
0.01
iiiiiiiiiiiiiitiiiiiii
iiiMiiiiiinniiiiiiiii
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IIMIIIII
IMIIIillllllllllllH
Illllllllllllllllll
Illllllllllllllllll
Illllllllllllllllll
• illllllllllllllll
iiiiiiiiiiiiiiiiiini
iiiiiiiiiiiiiiiiiii
Figure B-l. Ambient concentration data for POM in rural air in pg/m .
Data are summarized from RTI's 1978 draft report on POM,
ref. B-l. Each line represents specific values reported,
Dotted lines indicate ranges.
-------
a,o (a.)a y
0.0001
B-2
0-001
O.OJ
0.7
Figure B-2.
Ambient concentration data for POM in suburban air in
pg/m . Data are summarized from RTI's draft report on
POM, ref. B-l. Each line represents specific values
reported. Dotted lines indicate ranges.
-------
O.OCOOI
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Anthracene
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' -..^........-™ I;-jirj>Mi.jj._iui.^^,_ij.j,jiiiirti,,iitii.Mi.lii,illl,llll,lllllllll,l,llllllllllllllllll,ll,l,lllulll
Triplienylcne -f-i—"-~'—•——-—'
miiiii.iiiiiiiiiiiiiiitiiiiiiiiiuituiiiiiiiiiiitii.iiiiititn
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r.^i>iiini^n-:jnn,-;i.-|^MV.,-.-i;,iaiMj^r>.>iir^ri.ijjr,rlriTiirriijnriiiiiiiiililiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiil
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I
I
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i'tnuniininmiiiarirurnmfimTinff-Tiii.iiiiiiiuiii.iiiiiiiHiiliiin.iliiliiiiiiiiiiiiii
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i.-.»« .ini«it.Tu»i..-r..:.....-TlVr..^.J.^.»..«,r ^..^p^.—„„„.., i tintiiii minimum.
Figure B-3. Ambient concentration data for POM in urban air in ug/m . Data are summarized
from RTI's 1978 draft report on POM, ref. B-l. Each line represents specific
values reported. Dotted lines indicate ranges.
oo
-------
.fJ.V<3O\
.V.VOI
,0.01
,0.1
.1
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Figure B-3. CContinued)
-------
B-5
001
ififuniiinnin
t(iim.q
Figure B-4. Ambient concentration data for benzo(a)pyrene in urban
air in yg/rn . Data are summarized from RTI's 1978 draft
report on POM, ref. B-l. Each line represents specific
values reported. Dotted lines indicate ranges.
-------
0.001
0.01
0.1
1.0
10
.
vjround yVotpr
Lakes
iliycrs
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"(Carcinogenic PAH)
'.(Carcinogenic PAH)
CO
I
Figure B-5. Ambient concentration data for total POM in pg/fc in unpolluted water. Data are
summarized from RTI's draft report on POM, ref. B-l. Each line represents specific
values reported. Dotted lines indicate .ranges.
-------
.001
.01
.Pcnz(a)anthraccnc
Chryjcnjj
Pyrgnc
.1
10
• IMfllMHllllllllllHt
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09
Figure B-6. Ambient concentration data for POM in river water in ug/£. Data are summarized from
RTI's draft report on POM, ref. B-l. Each line represents specific values reported.
Dotted lines indicate ranges.
-------
1.0
Marino
(Marsh)
(Subtjcjul)
Remote Tcrrqs.tfM
Rural
Urban
10.0
100.0
1000.0
miiiittmimimiiiMiiniiiiiMiitti
iMItllitllltlMltlliinillllllllltllMMIIIIIIIIiltlillllMMIIIIilllllllllllMtllllMlMIIIIIMIiliniMlllllllltltlllHIItlt
• lllllltUIIIIMItlllMlllllllllltMilllllIIIMIIIIIIIIIIIIIIItlllltlltlllllllltlllllllimilttllllftlllllllllllltllltlllltlttllllllllllllltlUIIIflllllf
oo
i
oo
Figure B-7. Ambient concentration of total POM in ug/g in unpolluted soils. Data are summarized
from RTI's draft report on POM, ref. B-l. Dotted lines indicate ranges.
-------
1.0
10.0
Arcns
•
Mar mo
Forest Sg||
Residential
Natural Background
100.0
1.000.0
10,000.0
iiiiiiiiMMittiiiittiuiititiiiiMiiuitiniiUHuiiiiiiitiMiiiiiiiMtiaiiiiiiiiitiiniiiiiiuiiiiniiiiHitttnttiiiiitiiiiiiiiiiiiiiiHinititttiiiuii
MiiMiHmMimiimuMiiiiifiiiiiiiiuiiimMiMiiiitHiiimimiiiitmtiuitiimiiiiiim
IIIIIIUIIIIMMIMIIIllllllllllllltllllllllllllllllllMIIIIIIIIIIIIIMIMIItllllllllllllllltllllllllll
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imttmiiiimitiiimtititiiiiimiimtiiiiiiiiiiiiiiniiiiimiiiiitMiiii
00
I
Figure B-8. Ambient concentrations of benzo(a)pyrcne in various soils in ugAg- Data are summarized
from RTI's draft report on POM, ref. B-l.
-------
B-10
REFERENCE
B-l Research Triangle Institute. Draft Report: Sources and Ambient
Concentration Data for Polycyclic Organic Matter. June 1978.
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