United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S4-87/039 Jan. 1988
ŁEPA Project Summary
Chemical Characterization of
Polynuclear Aromatic
Hydrocarbon Degradation
Products from Sampling
Artifacts
J. C. Chuang, S. W. Hannan, and L E. Slivon
The objective of this study was to
characterize the polar components,
mainly polynuclear aromatic
hydrocarbon (PAH) derivatives, in air
samples and to determine whether
these compounds are from sampling
artifacts or from the sampled air.
A literature survey was conducted
to review the studies about polar
PAH derivatives found in the air. In
general, there Is limited chemical
and biological information for polar
PAH available in the literature. Most
of the studies revealed that PAH and
NO2-PAH cannot totally account for
indirect- and direct-acting
mutagenicity in air samples. The
polar fractions of air samples did
show a significant amount of
mutagenic activity. The authors
concluded that more studies are
needed in this area to determine the
polar components responsible for
the activity.
A storage stability study of PAH
collected on quartz fiber filters and
XAD-2 resin was conducted. The
results showed that some reactive
PAH including acenaphthylene and
cyclopenta[c,d]pyrene partially
decompose to napthalene and
pyrene dicarboxylic acid anhydrides
after storage for 30 days in the dark
at room temperature between
sampling and extraction.
The determination of unknown
polar components in air samples is a
complex task. The NCI GC/MS method
is a very sensitive technique for the
determination of NOa-PAH and
oxygenated PAH (OXY-RAH),
however, analyses of the standards
are required to confirm the
identification. The NCI and PCI MS/MS
techniques can provide char-
acteristic fragmentation patterns for
NO2-PAH and OXY-PAH,
respectively. More studies are
needed to evaluate a fast screening
method to determine these
compounds with MS/MS.
This Project Summary was
developed by EPA's Environmental
Monitoring Systems Laboratory,
Research Triangle Park, NC, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Polynuclear aromatic hydrocarbons
(PAH) have been extensively studied in
recent years and have received
increasing attention in the investigation of
air pollution. Many PAH are known to be
animal carcinogens, mutagens, or both.
Most PAH are likely to react with air,
sunlight, and other pollutants (03 NOX
and §02) in the atmosphere to form PAH
derivatives because PAH can absorb light
at the wavelengths found in sunlight
(>300 m). The PAH derivatives present
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in air arise partly from various
combustion emissions sources, in
addition to atmospheric transformation.
Degradation products of PAH may also
be formed as artifacts of sample handling
or sample storage conditions. Recently,
Battelle conducted a study which showed
that the amount of particle-bound
cyclopenta[c,d]pyrene decomposes to
about half of its original value after
storage for 30 days in the dark at room
temperature. In general, little is known
about the PAH degradation products
formed as sampling artifacts. However, it
has been demonstrated that PAH
degradation products may exhibit a
higher mutagenic activity than their
parent PAH. Therefore, it is important to
determine whether those PAH derivatives
are sampling artifacts or were actually
present in the air sampled.
Many studies have demonstrated that
PAH and NOa-PAH cannot totally
account for the indirect- and direct-
acting mutagenicity of air samples; other.
classes of compounds must also
contribute to the activity. In fact, the polar
fractions of air samples have shown very
strong direct-acting mutagenicity. In
some cases the activity of the polar
fraction is greater than 50 percent of the
total activity. The authors expect that
many of the PAH derivatives, such as
N02-PAH and oxygenated PAH (OXY-
PAH), are present in the polar fractions.
However, only limited biological and
chemical information is available for
these polar components in the air.
Therefore, a study was carried out to
characterize PAH degradation products
in air.
The objective of this study was to
characterize the polar components,
mainly PAH derivatives, in air samples
and to determine whether these
compounds are sampling artifacts or are
from the sampled air. This study
consisted of the following subtasks:
1. Conducting a literature survey to
review the studies about polar PAH
derivatives found in the air,
2. Performing a storage stability study of
PAH collected on quart fiber filters
and XAD-2 resin,
3. Conducting chemical characterization
of the day-0 and day-30 samples
in an attempt to determine the PAH
degradation products produced due
to storage, and
4. Preparing the samples from the
stability study for bioassay.
Procedure
A literature survey was performed by
a computer search of five data bases:
Chemical Abstracts (1967-1986), APTIC
(1966-1978), NTIS (1970-1986),
Medline (1970-1986), and Cancerline
(1970-1986). Abstracts or citations
considered most relevant to the subject
area were reviewed and divided into two
subsets: analytical and biological data,
for further evaluation. Photocopies of
some important articles were also
obtained to allow a more detailed
evaluation.
Two sets of four samplers were
located in parallel approximately two feet
apart, with the four samplers separated
from each other by about one foot.
Quartz fiber filters and XAD-2 resin in
series were used in all samplers.
Ambient air was sampled for 24 hours at
6.7 cfm flow rate. After collection, the
samples were stored as replicate pairs in
the dark at room temperature for 0, 10,
20, and 30 days before extraction. The
sample extracts were divided into two
portions: portion I used for chemical
analysis and portion II used for bioassay
analysis. Portion I of each XAD-2
sample was fractionated into four
fractions prior to chemical analysis. The
sample extracts and fractions were
analyzed by electron impact (El) and
negative chemical ionization (NCI) gas
chromatography/mass spectrometry
(GC/MS), as well as, triple quadruple
mass spectrometry.
Results
The results of the literature survey
showed that besides PAH, nitro PAH,
and hydroxy-nitro-PAH, the polar
fractions of the air particulate extracts
have also revealed mutagenic activity. It
appeared that oxygenated PAH (OXY-
PAH) may have also contributed to the
biological activity in other environmental
samples. However, there is a lack of
mutagenicity and carcinogenicity data on
individual OXY-PAH in the literature,
and more research should be directed to
studies of the biological activity of OXY-
PAH. Analytical methods including El
and Cl GC/MS or high pressure liquid
chromatography (HPLC) have been used
to determine polar PAH including NO2-
PAH and OXY-PAH. The analytical
methods to determine N02-PAH have
been well established compared to
methods for other polar PAH. No
systematic efforts have been made to
determine OXY-PAH. In most cases,
isomer-specific identification of OXY-
PAH was not possible by GC/MS alone.
A combination of different analytical
techniques was used to determine
isomeric OXY-PAH. Furthermore, the
absence of authentic standards
prevented the positive identification
isomeric OXY-PAH. The ability
determine specific isomeric compoun
is important, because some isome
compounds have quite different biologi'
activity. Therefore, more investigatic
are needed.
The results of the stability stu
revealed that the PAH vapors collecl
on XAD-2 resin appear to be stable o\
the 30-day storage, except f
acenaphthylene, indicating a sligh
decreasing concentration trend. T
results also indicated that most partic
bound PAH, except for cyclopen
[c,d]pyrene were not adverse
influenced by a 30-day storage tin
Both acenaphthylene a
cyclopenta[c,d]pyrene, -having simi
structure with vinylic bridges, are react!
PAH and can be expected to sh<
storage instability over 30 days.
It is likely the relatively localiz
double bonds in these reactive P^
oxidize to the corresponding Pi
dicarboxylic acid anhydrides duri
storage. Indeed, the levels
naphthalene and pyrene dicarboxylic ai
anhydrides from the day-30 sampl
were more than 1.5 times those of 1
day-0 samples. This finding clea
suggests that the acenaphthylene a
cyclopenta[c,d]pyrene partial
decompose to naphthalene and pyre
dicarboxylic acid anhydrides duri
storage. There were a few oth
components including nitroge
containing compounds and OXY-P/
that revealed increasing concentrati
trend during 30-day storage.
tentatively identified hydroxynitropyre
isomer and 2/3 nitrofluoranthene show
decreasing concentration trend af
storage. The authors also found a f
unknown components present only in 1
day-0 samples and not in the day-
samples.
The negative chemical ionization (N
MS/MS analysis of the NO2-P/
revealed characteristics collisic
activated dissociation (CAD) patten
which are M" (M-NO)', and NO
The hydroxynitropyrene showed t
same pattern of fragmentation ions as 1
N02-PAH, as well as (M-NO-OH
However, the estimated detect!
sensitivity of NCI MS/MS, in general,
lower than the conventional NCI GC/I
technique. The detection sensitivity c
be improved by performing the MS/MS
optimum instrumental sensitivity. Me
investigations need to be carried out
order to obtain a true comparison
detection limits for NO2-PAH and C
NO2-PAH for those two techniques w
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Cl GC/MS and NCI GC/MS/MS. There
were no characteristic fragmentation
patterns for OXY-PAH standards
observed in the NCI MS/MS analysis.
However, a specific CO neutral loss was
observed in the CAD spectra of OXY-
PAH, including polynuclear aromatic
aldehydes, polynuclear aromatic ketones
and polynuclear aromatic acid
anhydrides. More studies are needed to
optimize the detection sensitivity.
Conclusions and
Recommendations
In conclusion, there is limited
chemical and biological information on
PAH derivatives in air with the exception
of NO2-PAH. Therefore, more studies
are needed in this area to determine the
polar components responsible for the
mutagenic activity in air samples.
The results of the stability study
showed that the reactive PAH
acenaphthylene and cyclopenta-
[c,d]pyrene, partially decompose to
naphthalene and pyrene dicarboxylic
acid anhydrides after storage before
extraction for 30 days in the dark at room
temperature One of the degradation
products, pyrene-3,4-dicarboxylic acid
anhydride, has been reported as a
direct-acting mutagen. Therefore, future
air sampling studies should involve a
minimum of sample handling and storage
to reduce the degradation of reactive
PAH.
The determination of unknown polar
components in air samples is a complex
task. The El GC/MS analyses of the
unfractionated filter samples did not
detect PAH derivatives. Even though the
NCI GC/MS method is a very sensitive
method for the determination of NOa-
PAH and OXY-PAH, analyses of
standards are required to confirm the
identification. The authors conclude that
more investigation, such as fractionation
of the sample and evaluation of different
analytical methods is needed to
characterize the polar components in air
samples.
The authors recommend that a study
should be performed to investigate the
chemical and biological characteristics of
a series of reactive PAH and their
degradation products and to determine
the extent of mutagenic activity of PAH
degradation products from sampling
artifacts.
J. C. Chuang, S. W. Hannan. andL. E. Slivon are with Battelle Columbus Division,
Columbus. OH 43201.
Nancy K. Wilson is the EPA Project Officer (see below).
The complete report, entitled "Chemical Characterization of Polynuclear
Aromatic Hydrocarbon Degradation Products from Sampling Artifacts," (Order
No. PB 88-133 616/AS; Cost: $14.95. subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC27711
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