United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-83-015 a&b June 198
SERA Project Summary
Preparation and Evaluation of
New Sorbents for Environmental
Monitoring
Volume I and Volume II
Edo Pellizzari, Barbu Demian, Anton Schindler, Kathy Lam, and Wanda Jeans
Sixty-one different polyimide sor-
bents were prepared for evaluation as
sorbents for the collection of vapor-
phase organics in ambient air. Labora-
tory tests were applied to assess their
properties as sorbents and to develop a
data base for examining the relation-
ships between chemical structures
and physical properties. A tiered level-
of-effort testing was applied. The Level
I procedure sorted the polymers ac-
cording to specified desired properties.
Level II testing provided information
for selecting the most promising poly-
mers for trapping of vapor-phase or-
ganics and generated the data base
relating chemical and sorbent proper-
ties. Level III experiments provided a
confirmation of the physio-chemical
properties of the sorbent Thermody-
namic properties and correlations be-
tween chemical structures were deter-
mined for the four most promising
polyimide sorbents and compared to
Tenax GC*, the reference sorbent
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 docu-
mented in a separate report of the
same title (see Project Report ordering
information at pack).
Introduction
A wide variety of pollutants exists in the
form of vaporized organics in our environ-
ment The biological effects of amounts
even as small as a few nanograms per
cubic meter may constitute an indefinable
health hazard Ambient air sampling in-
volves the collection of low levels of
organics that are contained in relatively
high levels of water vapor. To detect such
small amounts of compounds, pre-con-
centration of the sample is necessary. The
most successful method for ambient air
sampling of vaporized organics involves
the use of porous polymers as solid
sorbents in pre-concentration cartridges.
The most widely used solid sorbent Tenax
GC®, a porous polymer of 2,6-diphenyl-
para-phenylene oxide, has been found
inadequate for organic compounds that
have high volatility. Also, reactive gases
such as ozone, nitrogen oxides, and sulfur
oxides cause changes in the organic com-
position of the sorbent
In this research, 61 polyimide sorbents
were evaluated in a three-tiered scheme
for their utility in collecting vapor-phase
organics from ambient air. The primary
objective in these tests was to develop a
sorbent with good thermal properties, i.e.,
minimum background contribution to avoid
sample contamination, low retentive vol-
ume for water vapor, and resistance to
reactive inorganic gases. In the presence
of such reactive compounds the ideal
sorbent would yield minimal artifacts.
A number of sorbent materials previ-
ously have been tested by the Research
Triangle Institute (Research Triangle Park,
NC) under contract to the U.S. Environ-
mental Protection Agency (EPA). Tenax
GC®, the reference sorbent, and other
commercial sorbents display selectivity,
but not enough specificity, in view of the
number of closely related aromatic and
aliphatic compounds present in ambient
-------
air. Collection problems have been en-
countered in using commercial solid sor-
bents to sample those organic compounds
not amenable to monitoring with Tenax
GC®. For this reason, new polymers were
synthesized for use in the screening
review.
The screening system employed three
evaluations, each increasingly more speci-
fic, to narrow down the field to the most
selective sorbents. Also, part of the pro-
cedure as a secondary goal was the deter-
mination of empirical parameters that
could provide correlations between the
chemical structures and physical proper-
ties of sorbents. It was hypothesized that
through the identification of relationships
between the solubility parameters and the
retention volumes of sorbents, a model
could be developed that would predict
sorbent properties from polymer structures
Procedure
Sixty-one polyimides with different chem-
ical structures were synthesized for evalu-
ation and screening. A list of the polyimides
by their identifying numbers and the aro-
matic diamines used in preparation is
presented in Table 1. The poly (amidic
acid) precursor was formed by the heter-
ogeneous reaction of a diamine (any of
various commercially available diamines)
in tetrahydrof uran with either of two dian-
hydrides, pyromellitic dianhydride(PMDA)
or 2,2',4,4'-benzophenone tetracarboxylic
dianhydride (BTDA), followed by cyclo-
dehydration of the particles to form the
polyimide.
For the three-tier screening process,
gas chromatography measurements were
used to monitor adherence to adsorbence
criteria, which were more specific for each
level. Laboratory and field applications
were both considered, including, for ex-
ample, artifact formation, shelf and storage
life, and quality assurance parameters.
Level I testing screened selected polymers
according to desired characteristics. Of
particular interest was their ability to
adsorb volatile vapor-phase organics not
adequately adsorbed by Tenax GC®, such
as compounds with four or fewer carbons,
polar neutral species, organic acids, or-
ganic bases, halocarbons,and halohydro-
carbons.
In Level II tests, the best sorbents from
Level I were selected and reproduced. The
empirical parameters on which to base
correlations between the polymer's chem-
ical and sorbent qualities were defined.
They included peak asymmetry factors for
selected test compounds; dependence of
retention volumes on analyte quantity;
effect of temperature on retention volume;
Table 1. Polyimide Sorbents Prepared from Pyromellitic Dianhydrides and Different Aromatic
Diamines*
Polyimide Number
Diamine
PI-101
PI-102
PI-103
PI-104
PI-105
PI-106
P/-107
PI-108
PI-109
PI-110
PI-111
PI-112
PI-113
PI-114
PI-115
PI-116
PI-117
P/-118
P/-119
PI-120
PI-121
PI-122
PI-123
PI-124
PI-125
P/-126
PI-127
P/-128
P/-129
PI-130
PI-131
PI-132
PI-133
PI-134
P/-135
PI-136
PI-137
PI-138
PI-139
P/-140
PI-141
PI-142
PI-143
PI-144
PI-145
PI-146
PI-147
PI-148
PI-149
PI-150
PI-151
PI-152
PI-153
PI-154
PI-155
PI-156
PI-157
PI-158
P/-159
PI-160
P/-161
PI-162
PI-163
PI-164
PI-165
PI-166
Tetra fluoro-m-phenylene diamine
a. a- Diaminotetrachloro- p-xylene
4-Chloro-m-phenylene diamine
Bis(4-amino-3-chlorophenyl)methane
2,6- Diaminotoluene
4-Azo-dianiline
2,2', 5,5'- Tetrachlorodiphenyldiamine
Bis(4-amino-3-chlorophenyl)methane
3,3',5,5'-Tetramethylbenzidine
Octafluorobenzidine
2,6- Diaminopyridine
Bis(4-aminophenyl)sulfide
2,2',5,5'- Tetrachlomdiphenyl
Tetrafluoro-m-phenylene diamine
2,6-Dichloro-p-phenylene diamine
Bis(3-aminophenyl)sulfone
2,6-Diaminopyridine
Tetrafluoro-p-phenylene diamine
Bis(4-aminophenyl)sulfone
Bis(4-aminophenyl)ether
4,4'-Diamino-3,3'-dichlorodiphenyl
1,5-Diminonaphthalene
1,2-Bis(4-aminophenyl)ethane
2-Chloro-p-phenylene diamina
4,4'-Diaminodiphenylmethane-2,2'-sulfone
3- Trifluoromethyl- m-phenylene diamine
3,6-Diamino-2,7-dimethylacridine
Tetramethyl-p-phenylene diamine
2,5- Diaminopyridin e
4,6- Diaminopyrimidine
3.3'-Diaminobenzophenone
3,6-Diaminoacridine
1,4-Diaminoanthraquinone
o-Toluidine
2,6-Diaminoanthraquinone
2,6-Dichloro-p-phenylene diamine
2,6-Dichloro-p-phenylene diamine
2,6-Dichloro- p-phenylene diamine
2-Chloro-p-phenylene diamine
2,6-Dichloro-p-phenylene diamine
2,6-Dichloro-p-phenylene diamine
4,4'-Ethylene- m-toluidine
p-Phenylene diamine
m-Phenylene diamine
2-Chloro-p-phenylene diamine
2,4-Diaminotoluene
2,4-Diaminocumene
Bis(2-aminophenyl)disulfide
Bis(4-aminophenyl)methane
Bis(3-aminophenyl)methane
Octafluorobenzidine
2,5- Diaminotoluene
4,4'-Diaminostilbene
Bis(4-aminophenyl)sulfone
a, a- Diamino- m-xylene
2,6-Dichloro-p-phenylene diamine
Bis(4-aminophenyl)sulfone
2,6-Dichloro-p-phenylene diamine
Bis(4-aminophenyl)sulfone
2,6-Dichloro-p-phenylene diamine
2-Chloro-p-phenylene diamine
2-Chloro-p-phenylene diamine
2,6-Dichloro-p-phenylene diamine
3,3'5,5'- Tetramethylbenzidine
4-Azo-dianiline
3,3',5,5'- Tetramethylbenzidine
-------
Table 1. fContinued)
Polyimide Number
Diamine
PI-167
PI-168
PI-169
PI-170
PI-171
PI-172
PI-173
4-Azo-dianiline
4-Azo-dianiline
4,6- Diaminopyrimidine
3,3',5,5'-Tetramethylbenzidine
4,6-Diaminopyrimidine
4,6-Diaminopyrimidine
4,6-Diaminopyrimidine
* Sixty-one different polyimides were prepared in 73 batches.
surface area measurement; background
assessment from thermal desorption; and
potential artifact products from inorganic
gases reacting with the polymide sorbents.
In Level III, the rating of the best
sorbents was reconfirmed for each of the
selected polyimides. In addition, the chro-
matography model was used for multiple,
independent assessments to confirm the
physical and chemical correlations of the
sorbent This model established a function
between specific retention volumes at a
specific temperature and the solubility
parameters of the solute. Two regression
analyses were used in making the corre-
lations: 1) intercepts of retention volumes
versus temperature regressions, and 2)
slopes of the lines.
Results
The utility of the screening system
devised for these sorbents was demon-
strated. Following Level III screening, four
sorbents, PI-109, PI-11 5, PI-119, PI-149
(shown in Figure 1), were selected for
further studies. In these studies, break-
through data from chromatographic ex-
periments on these sorbents proved to be
reproducible. Finally, the retention volumes
of selected organ ics were one to two
orders of magnitude greater for the four
polyimides than for Tenax GC®.
Conclusions and
Recommendations
Several new solid sorbents have been
synthesized that have the potential of
either replacing or complementing Tenax
GC9.
Additional characterization of these new
polyimides is necessary in the area of
density, surface area, pore volume, and
pore size, etc. Further studies on collection-
desorption efficiencies, artifact formation,
shelf life, humidity, and the effects of
inorganic species such as ozone, nitrogen
oxides, and sulfur oxides are also planned.
In order to perform these additional studies,
larger batches of the four most promising
polyimides will have to be prepared. They
will be prepared in such a way as to
determine batch-to-batch variability, which
has been shown to be a problem in com-
merciaJly available sorbents.
Figure 1. Chemical Structures of the Four
Polyimide Sorbents, PI-109, PI-
US, PI-119, and PI-149
Edo Pellizzari, Barbu Demian, A nton Schindler. Kathy Lam, and Wanda Jeans are
with Research Triangle Institute, Research Triangle Park. NC 27709.
James D. Mulik is the EPA Project Officer (see below).
The complete report consists of two volumes, entitled "Preparation and Evaluation
of New Sorbents for Environmental Monitoring:"
"Volume I," {Order No. PB 83-195 974; Cost: $25.0O, subject to change)
"Volume II. Synthesis and Quality Control Testing of Sorbents for Air
Monitoring," (Order No. PB 83-195 982; Cost: $7.00, subject to change)
The above reports will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, v'A 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, NC 27711
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
USS ENVIR2PROTECTION AGENCY
CHICAGO IL 60604
-------
United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-83-014 June 1983
&EPA Project Summary
Evaluation of a Passive Monitor
for Volatile Organics
Robert W. Coutant
A laboratory investigation was con-
ducted to determine the potential utility
of a commercially available passive
dosimeter for monitoring toxic volatile
organic compounds at ambient levels.
Test compounds included: chloroform,
methylchloroform, carbon tetrachloride,
trichloroethylene, tetrachloroethylene,
benzene, and chlorobenzene.
Feasibility for reduction in device
blanks was demonstrated and improve-
ments were made in the analytical
procedures. Chamber tests of device
performance showed generally good
performance at ambient levels, but indi-
cated a severe limitation in sampling
ability at relative humidities greater
than about 80 percent. Also, generally
low results were obtained with carbon
tetrachloride. The cause of the ob-
served effect of air velocity on sam-
pling rates was examined on a theo-
retical basis, and it is recommended
that these devices not be employed
without adequate ventilation.
It is concluded that at least one
currently available passive dosimeter
could be useful for monitoring of am-
bient levels of toxic organic chemicals,
and appropriate precautions are indi-
cated.
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 doc-
umented in a separate report of the
same title fsee Project Report ordering
information at back).
Introduction
In recent years an increased awareness
of the need for monitoring of individual or
personal exposures to pollutants and toxic
chemicals of various types has evolved.
This awareness has prompted the develop-
ment of a variety of personal sampling
devices including battery driven pump
systems (active systems), passive systems
having high specificity for individual com-
pounds, and generalized passive systems
intended for collection of volatile organic
compounds. Initial applications of these
various devices have been concerned with
the relatively high concentrations of con-
taminants found in industrial workplaces.
In an earlier program conducted for the
Environmental Monitoring Systems Labora-
tory, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina
(RTP), Battelle's Columbus Laboratories
(BCL) explored the problems and limita-
tions associated with the potential use of
passive devices for monitoring ambient
level toxic organic chemicals (1). This
current Work Assignment was concerned
with the alleviation of some of the problems
associated with this application of passive
monitors and with a laboratory level evalua-
tion of the performance of passive monitors
at ambient concentrations.
The objective of this task was to evaluate
the utility of selected passive monitors for
their applicability to 24-hour monitoring
of volatile organic compounds at typical
ambient concentration levels. Seven target
compounds that are representative of vola-
tile toxic chemicals relevant to EPA moni-
toring requirements were considered.
These included chloroform, 1,1,1 -trichloroe-
thane, carbon tetrachloride, trichloroethy-
lene, tetrachloroethylene, benzene, and
chlorobenzene.
Procedures
Analytical Methodology
Analyses of exposed badges were per-
formed by solvent extraction of the collec-
tors followed by gas chromatographic
-------
quantitation of sample aliquots. The use of
fused-sihca capillary column techniques
was compared with previously employed
packed-column procedures. An in-series
combination of electron capture and photo-
ionization detectors was used for quantita-
tion. Reference levels of chemicals used in
the exposures were determined by direct
gas sampling, using the same chromato-
graphic system.
Device Blanks
Discussions were held with representa-
tives of manufacturers of passive organic.
samplers for the purpose of determining
potential solutions to the problem of high
blank levels associated with these devices.
One manufacturer, DuPont supplied several
series of devices that were prepared under
a variety of conditions. These were then
analyzed to determine the most effective
means for minimization of blank levels.
Chamber Tests
Triplicate sets of DuPont badges were
exposed to the test chemicals at concentra-
tions of 10"1 to 102 ppbv under well-
controlled conditions in a 200 L chamber.
Test variables included concentration, rela-
tive humidity, and exposure time.
Comparison Basis
The rate of collection of a volatile sub-
stance by a passive sampler is determined
by the product of the intrinsic sampling
rate, a function of the physical characteris-
tics of the device and the diffusion coeffic-
ient for each substance, and the exposure
concentration. Inasmuch as the effects of
these two variables cannot be separated in
any given experiment, it must be assumed
that one or the other is known. In the
current work, it was assumed that the
intrinsic sampling rates specified by the
manufacturer were correct, and perfor-
mance comparisons were made relative to
the apparent concentrations indicated by
the analyses.
Results
Analytical Methodology
Fused-silica capillary column techniques
have been used to improve the overall
quality of the analytical procedures for
passive device analysis. Thermal desorp-
tion was shown not to be a viable approach
for analysis of the carbon-based collectors
used in these devices.
Device Blanks
The problem of high and variable blanks
for these devices was discussed with
manufacturers, and one manufacturer,
DuPont, was able to demonstrate capa-
bility for production of devices having
satisfactorily low blank levels, without
adding undue cost to the production of the
devices. Blanks for the "clean" DuPont
badges were close to or below detection
limits for the test chemicals.
Chamber Tests
Examples of the DuPont badge were
exposed in triplicate sets to concentra-
tions of 10"1 to 102 ppbv of the test
chemicals under controlled chamber con-
ditions. No effect of concentration in this
range was discernible. The apparent re-
sponses to all of the chemicals were,
however, diminished at relative humidities
of 80 percent and higher. Relative re-
sponses (observed apparent concentra-
tion/actual concentration) for a given
chemical were strongly correlated to re-
sponses for other chemicals with the
same badge, i.e., when the response for
one chemical was high, responses for all
other chemicals on the same badge also
tended to be high. This observation sug-
gests that differences from one badge to
the next were due largely to variations in
physical parameters of the individual
badges. In some cases, this was believed
to have been caused by faulty seals be-
tween the diffusor plates and the collector
chambers. One approach to illustrate the
potential magnitude of the variability due
to badge construction problems is to nor-
malize the responses for each badge with
respect to the mean response for that
badge. The standard deviations in response
for a given chemical can be compared for
the raw data and normalized data to yield a
measure of the effect. A summary of
average responses obtained for each chem-
ical studied and the standard deviations
before and after normalization is shown in
Table 1. These data suggest that approxi-
mately one-half of the variation observed
in the raw data may be due to physical
differences between the individual devices.
The remaining variation is consistent with
the total analytical uncertainty associated
with the procedures that were used.
Table 1. Average Response Ratios
Conclusions and
Recommendations
It is concluded that the blank and anj
lytical problems previously identified fc
the use of passive monitors at ambier
levels of toxic volatile organic compound
can be minimized satisfactorily. The usec
thermal desorption for the analysis c
carbon-based collectors used in these de
vices is not recommended. Chamber test
of the performance of the DuPont badg
indicate that reasonably accurate samplin
can be achieved at concentrations of 10"
to 102 ppbv as long as the relative humidit
is below approximately 80 percent How
ever, at relative humidities higher tha
about 80 percent the apparent samplin
rates are reduced by about 50 percen
The available list of sampling rates need
to be extended and validated, but thi
aspect is being pursued independently b
the manufacturer. Sources of occasionall
high apparent sampling rates are believe'
to be related to variations in manufacture
quality control and this too is being inves
tigated by DuPont.
It is recommended that further cor
sideration be given to the performance c
passive devices under field conditions. I
these tests, passive monitors should b
compared with currently used active de
vices and with direct sampling and anal\
sis methodology where possible.
References
1. Coutant, R. W., and D. R. Scott, "Ar.
plicability of Passive Dosimeters fc
Ambient Air Monitoring of Toxic Oi
ganic Compounds." Environ. Sc
Technol., 76410-413(1982).
Chemical
Chloroform
Methylchloroform
Carbon tetrachloride
Trichloroethylene
Tetrachloroethylene
Benzeneta>
Chlorobenzenef")
Raw
R
0.94
1.19
0.73
1.07
0.98
(0.97)
(0.96)
Data
SDev
0.29
0.31
0.26
0.32
0.33
(0.45)
(0.34)
Normalized Data
R
0.96
1.19
0.71
1.05
0.96
(0.94)
(1.07)
SDev
0.12
0.18
0.11
0.13
0.11
(0.17)
(0.28)
/a/ Limited data (indicated by parentheses).
-------
Robert W. Coutantis with Battelle Columbus Laboratories. Columbus, OH 43201.
Donald Scott and James D. Mulik are the EPA Project Officers (see below).
The complete report, entitled "Evaluation of a Passive Monitor for Volatile
Organics," (Order No. PB 83-194 464; Cost: $ 10.00, subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officers can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
PS 0000329
U S ENVIR PROTECTION AGENCY
REGION 5 LIBRARY
230 S DEARBORN STREET
CHICAGO IL 60604
-------
United States
Environmental Protection
Agency
Environmental Monitoring Systems
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S4-83-016 June 1983
Project Summary
Ambient Acrylonitrile Levels
Near Major Acrylonitrile
Production and Use Facilities
Stephen J. Howie and Eugene W. Koesters
This summary describes a study un-
dertaken to determine the acrylonitrile
(AN) levels near selected manufactur-
ing plants that are either major users or
producers of AN, and also to measure
the difference, if any, in the concentra-
tion levels near the two types of facilities.
Data gathering was done over a four-
month period, and involved taking 24-
h air samples on charcoal tubes for 10-
12 consecutive days near the selected
plant sites.
Resu Its show that many factors affect
the recorded AN levels, including mete-
orological conditions, distance of sam-
pling site from plant and certain geo-
graphical elements (such as bodies of
water). Although study results pointto
higher AN concentration levels near
user facilities than producers, the study
did not provide an adequate data base
from which to draw definite conclu-
sions.
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 doc-
umented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
This report describes a study in which
data were gathered to verify the presence
of ambient acrylonitrile (AN) in the vicinity
of industrial plants that are major users or
producers of AN. This study was also to
determine the difference, if any , of AN
concentration levels near user and pro-
ducer facilities.
PEDCo Environmental, Inc., performed
the field work, which involved taking 24-h
air samples on charcoal tubes for 10 to 12
consecutive days at sampling stations near
the selected plants. Data gathering took
place from June through September 1981
at the following facilities:
• Monsanto in Texas City, Texas
• Monsanto in Decatur, Alabama
• Borg-Warner in Washington, West
Virginia
• Vistron (SOHIO) in Lima, Ohio
Procedure
A preliminary one-day pilot test was
conducted in the vicinity of each plant to
evaluate the performance of two different
size adsorbing tubes. Based on the pilot
test results, 150-mg standard charcoal
sorption tubes were used during this study.
After samples were taken, tubes were
stored on dry ice before shipment to the
two analysis laboratories (PEDCo, Cincin-
nati, Ohio and Research Triangle Institute
[RTI], Research Triangle Park, North Caro-
lina). Samples were shipped in insulated
boxes containing an ice substitute chilled
before shipment to the temperature of dry
ice. Quality control and field samples be-
tween the two laboratories were shipped
in insulated boxes containing dry ice.
During the pilot test samples were split
evenly between RTI and PEDCo for analysis
During the actual data gathering test
PEDCo was the primary analysis laboratory,
and a designated portion of replicate field
samples was sent to RTI to determine
interlaboratory method precision.
In evaluating the data presented in this
report, the following factors must be con-
sidered:
• Location of sampling stations was
influenced by the practicality of ob-
-------
taining access permission to many
areas, and by the presence of physical
barriers, such as bodies of water,
near plants to be tested.
• " Normal" plant operations were veri-
fied with Monsanto, Borg-Warner,
and Vistron personnel during testing,
but recording day-to-day events af-
fecting potential AN emissions(such
as production and use or process
upsets) was beyond the scope of this
project
• Month-to-month and seasonal vari-
ations in AN levels are not accounted
for.
The report presents details of the tech-
niques used for sampling and for analysis
by gas chromatography. Because of the
small number of measurements involved,
precision and accuracy assessments were
not made during the pilot test During the
actual data gathering efforts the following
precision and accuracy assessments were
made:
• Charcoal tubes were spiked with AN.
These tubes were prepared in quad-
ruplicate and divided evenly between
PEDCo and RTI for analysis.
• Samples were analyzed in duplicate
to assess laboratory method precisioa
• Collocated field samples were divided
between PEDCo and RTI to determine
interlaboratory method precision.
• Samples were analyzed by gas chro-
matography/mass spectrometry (GC/
MS) to confirm the presence of AN.
• Sample flow rates were set and
checked by a flow measurement de-
vice (proven linear and accurate to
±5 percent throughout the flow mea-
surement range used). Initial and
final sample flow rates were record-
ed to correct sample volume error
due to changes in sample flow rate
over tima
In cases where wind speed and direc-
tion information was gathered, the fol-
lowing operation checks were made daily
to ensure collection of accurate data:
• Check of wind zero accuracy
• Check of wind direction accuracy
• Data inspection to spot trends
Results
Various levels of AN were found in the
vicinity of each plant tested. Table 1
presents the results of the highest AN
levels found in each sample day, the
distance from the AN use or production
areas at which the sample was collected,
and the average values for each plant This
table indicates that the facilities that use
AN (Monsanto-Decatur, AL and Borg-
Warner--Washington, WV) generally are
associated with higher ambient AN con-
centrations than the producer facilities
(Monsanto-Texas City, TX and Vistron—
Lima, OH). However, it is not clear from
these limited data whether the higher
fenceline levels found at the producer
facilities were due to higher AN emissions
or other factors, such as sampler proximity
to the AN sources.
Listed below are the results of interla-
boratory bias (IB) assessments based on
analyses of charcoal tubes spiked with
AN. IB assessments showed a greater
probability of error at the Texas City Mon-
santo plants than at the other three plants.
An analytical inconsistency was discovered
following analysis of this plant's samples;
but after remedial steps were taken these
tests showed a marked improvement.
SITE IB(%)
Texas City, TX 34.1
Decatur, AL 26.8
Washington, WV 7.4
Lima, OH 6.0
(Based on pooling all data, the overall IB
was 10.6%.)
Table 1.
Highest AN Values on Each Sample Day
Values are in parts per billion fppb)
Table 2 presents the results of additional
precision and accuracy assessments. Inter-
laboratory total method precision, based
on dividing collocated field samples be-
tween analysis laboratories, is the as-
sessment snowing the "worst case" pre-
cision error encountered. The precision
estimates obtained using interlaboratory
analysis of collocated field samples showed
a variation coefficient of 14.6 percent at
levels above 10 ppb. Below 10 ppb,
precision data showed a variation coeffic-
ient of 22.8 percent (Since this type of
precision error showed different charac-
teristics above and below 10 ppb, different
computation methods were used.) Other
precision assessments presented in Table
2 indicate that collocated field samples
analyzed by only one laboratory (intra-
laboratory total method precision) showed
improved reproducibility, and that analyti-
cal precision (repeat analyses of desorbed
samples) was not a significant source of
error in either of the analysis laboratories.
Breakthrough determinations demonstrat-
ed that AN was efficiently collected by the
charcoal sampling tubes, as approximately
90 percent of the AN found was contained
in the first sections of charcoal.
Conclusions and
Recommendations
Confirmation GC/MS analyses of selec-
ted samples (samples showing AN by
GC/FID analysis) showed positive identifi-
cation of AN in all cases which indicates
that interfering compounds were not caus-
ing erroneous measurement of AN.
Dispersion modeling consideration, typ-
ically used to support monitoring activities
as well as the regulatory decision-making
process, indicate a decrease of pollutant
concentration with distance from the AN
use or production area. This decrease can
be substantial in distance ranges of, for
example, 0.1 to 2.0 km, and may be
Sample day
10
11
12 Mean
Monsanto TX (prod)
distance (km)
Monsanto AL (use)
distance (km)
Borg-Warner WV(use)
distance (km)
Vistron (SOHIO) OH (prod)
distance (km)
11.
0.5
20.
0.2
8.1
1.0
TFf
2.0
24.
0.3
36.
0.2
20.
0.8
TFf
2.0
5.4
0.7
57.
0.2
83.
0.5
4.0
2.0
4.7
0.5
15.
0.2
29°
0.5
4.1
2.0
8.1
0.5
10.
0.2
11.
1.0
TFf
0.8
15.
0.5
11.
0.1
17.
0.5
8.4
0.8
13.
0.3
50.
0.2
33.
0.5
6.1
0.8
6.6
0.3
37.
0.2
30.
0.5
6.0
0.8
5.2
0.5
52.
0.2
55.
0.5
TFf
1.0
5.2
0.3
130. 97.
0.2 0.2
11.
0.5
TFf
0.6
9.8
0.44
14. 44. 1
0.2 0.2
29.7
0.6
>4.1
1.3
aProperty enclosed by Borg-Warner fenceline on all sides.
bTR is less than 2.5 ppb; assumed to be 2.5 for averaging.
-------
Table 2. Summary of Quality Assurance Precision and Breakthrough Tests
Total method precision
Below 10 ppb, %
Above 10 ppb, %
Combined, %
Interlaboratory
22.8
14.6
N/A"
Intralaboratory
8.9
6.5
N/A*
Analytical
Precision
RTI
N/Aa
N/Aa
2.2
PEDCo
N/Aa
N/Aa
1.9
Breakthrough
RTI
N/Aa
N/Aa
10.5
PEDCo
N/A"
N/A3
12.3
aData below and above 100 ppb were combined since different measured levels appeared to have
little effect on results.
bData could not be combined due to different characteristics at different ranges.
partially responsible for the lower AN
levels found near the producer facilities.
A more detailed sensitivity analysis is
necessary to investigate and identify those
factors contributing to maximum concen-
trations at each plant The results at hand
suggest that AN concentrations near user
facilities are higher than near producers,
but do not necessarily provide an adequate
data base from which to draw definite
conclusions.
S. J. Howie and E. W. Koesters are with PEDCo Environmental, Inc., Cincinnati,
OH 45246-0100.
Robert H. J lingers is the EPA Project Officer (see below).
The complete report, entitled "Ambient Acrylonitrile Levels Near Major Acrylo-
nitrile Production and Use Facilities." (Order No. PB 83-196 154; Cost: $16.00,
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, NC 27711
-------
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Environmental Protection Information Env.ronmental
Agency Cincinnati OH 45268 Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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