United States
Environmental Protection
Agency
Atmospheric Research and Exposure
Assessment Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S3-90/006 June 1990
&EPA Project Summary
Annual Report on Performance
Audit Results for POHC Testing
During RCRA Trial Burns-
Status Report #2
F*. K. M. Jayanty, S. B. Tompkins, V. R. Bryant, and G. B. Howe
Audit materials containing Principal
Organic Hazardous Constituents
(POHCs) have been developed by
EPA for use by federal, state, and
local agencies or their contractors to
assess the accuracy of measurement
methods during RCRA trial burn
tests. Audit materials are currently
available for 27 gaseous organics in
five, six, seven and nine component
mixtures at parts-per-billion levels (7
to 10,000 ppb) in compressed gas
cylinders in a balance gas of
nitrogen. The criteria used for the
selection of the gaseous organic
compounds is described.
Stability studies indicate that all of
the organics tested (with the
exception of ethylene oxide and
propylene oxide below 10 ppb levels)
are stable enough to be used as
reliable audit materials.
Subsequent to completion of the
stability studies, 196 performance
audits have been conducted with the
audit materials to assess the
accuracy of the Volatile Organic
Sampling Train (VOST) and bag
measurement methods during or
prior to RCRA trial burn tests. The
results of those audits and a
summary table of the audits
conducted for each POHC and the
measurement system audited is
described in this report. The audit
results obtained with the audit gases
during or prior to RCRA trial burn
tests are generally within ±50
percent of the audit concentrations
measured by Research Triangle
Institute.
This Project Summary was
developed by EPA's Atmospheric
Research and Exposure Assessment
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
The determination of POHC at trace
levels (<50 ppb levels) during hazardous
waste trial burn tests requires
sophisticated sampling and analysis
systems. Agency personnel responsible
for trial burn tests need to be concerned
about the accuracy of POHC
measurements. Accuracy of such
measurements may be assessed by
conducting a performance audit. A
performance audit is a quantitative
assessment of the accuracy of a
measurement system. When a
performance audit is conducted during or
prior to a hazardous waste trial burn test,
it provides an assessment of the
measurement accuracy and indicates the
presence of any bias for the combined
sampling and analysis system.
The Quality Assurance Division of US
EPA's Atmospheric Research and
Exposure Assessment Laboratory has
initiated a program to supply audit
materials for use during hazardous waste
trial burn tests. The Research Triangle
Institute (RTI), under contract with US
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EPA, is the principal organization for
development of audit gases and
coordinating subsequent audits using
these gases. The main objectives of this
program are: (1) to evaluate the quality of
measurements made by federal/
state/local agencies, or their contractors
by using ppb gas cylinders for
performance audits to assess the relative
accuracy of source measurement
systems during hazardous waste trial
burn tests; (2) to verify the
manufacturer's certified analysis of the
multi-component gas mixtures; (3) tc
determine the stability of the gas
mixtures over time; and (4) to develop
new audit materials as requested by US
EPA.
Currently, 27 gaseous compounds
selected on the basis of the anticipated
needs of US EPA's Office of Solid Waste
and Office of Air Quality Planning and
Standards have been investigated for
suitability as audit materials. Table 1 lists
the organic compounds and the
concentration ranges currently available
in the ppb level cylinder gases. The
balance gas for all gas mixtures is
nitrogen and the cylinder construction
material is aluminum. A summary of the
performance audits conducted during or
prior to RCRA trial burn tests has been
described in this paper.
Criteria Used for Selection of
Organic Compounds
In 1983, EPA initiated a program to
develop ppb cylinder gas standards
containing hazardous organic compounds
that could be used to audit voleitile POHC
measurement systems during trial burn
tests. Through 1985, three mixtures of
ppb cylinder gases were developed
which are shown in Table 1. The criteria
used by EPA for selecting various
organic compounds in the three mixtures
(Groups I, II and III) are described in a
separate publication.1 On the basis of the
experience of EPA's Air and Energy
Engineering Research Laboratory
(AEERL) with RCRA trial burn testing,
five, nine, and seven compound gas
standards were developed during 1983 to
1985. Several compounds were included
in the same cylinder with the idea that
the same gas cylinders could be used to
audit more than one POHC during trial
burn tests.
In 1986, a six-compound Group IV gas
standard was developed. The selection of
the six organic compounds for Group IV
was based on EPA health risk
assessment studies plus input from a
state agency. The compounds included
in Group IV are also shown in Table 1.
Selection of Compound
Concentrations for Audit
Materials
The gas standards were initially
developed at two concentration ranges to
audit the two prevalent test methods for
volatile POHCs. The 7 to 90 ppb and 90
to 430 ppb concentration ranges were
selected for the Groups I, II, III, and IV
gas standards to audit POHC
measurements during RCRA trial burn
tests; the lower range standard is used to
audit VOST measurements, and the
higher gas standard is used to audit bag
sampling measurements. Later, Group I
and IV standards in the 430 to 10,000
ppb concentration range were added.
These standards were added because
the RCRA regulation requires a
Destruction and Removal Efficiency
(ORE) of at least 99.99 percent but does
not regulate a maximum emission rate for
the POHCs. Therefore, some source
testers have received approval to conduct
the trial burn test in such a manner that
POHC concentrations in stack emissions
are about 1000 ppb. Trial burn tests of
this higher concentration (i.e., 1000 ppb)
reduces considerably the effect of
atmospheric POHC contamination on the
VOST measurement system, compared
to trial burn tests where the POHC stack
emissions are on the order of 10 to 50
ppb concentrations.
Performance Audit Procedure
As stated previously, the EPA (through
RTI) supplies cylinder gases containing
selected POHCs for audit upon request
from federal, state, or local agencies or
their contractors. The contractors must,
however, be performing hazardous waste
trial burn tests on behalf of EPA or one of
these other agencies to qualify for the
performance audit. In fact, the VOST
method described in the EPA manual
SW-846 specifically requires an audit
during the trial burn.2 A performance
audit must be conducted simultaneously
with the actual planned test. A
performance audit prior to a trial burn test
to assess the proficiency of the
measurement system (including the
sampling and analytical personnel) is
recommended but not required.
When a request is received, the
cylinder pressures are measured and the
cylinders are shipped by overland carrier.
When a cylinder gas is used to audit the
VOST system for a trial burn test, an
aluminum suitcase is also sent. The
aluminum suitcase contains a gas
regulator, glass manifold with heating
tape, and necessary tubing and fittings to
draw the cylinder gas sample into the
glass manifold. The audit gas is then
drawn at atmospheric pressure from the
manifold into the VOST system. A letter
is included with the audit cylinder which
gives general instructions for conducting
the audit. The audit results are reported
to the agency (federal, state, or local)
coordinator requesting the audit. There is
no charge to the user except the cost of
returning the audit cylinder and aluminum
suitcase.
Performance Audit Results and
Discussion
As of September, 1988, 379 perform-
ance audits have been initiated using ppb
audit gases. Of these 379 ppb audits, 196
audits have been initiated to assess the
accuracy of measurement methods
(VOST or bag for sampling and GC/MS
or GC with specific detector for analysis)
during or prior to hazardous waste trial
burn tests. Of the 196 RCRA audits, 179
are complete and the results are
summarized in this report. For the 179
completed audits, the frequency each
compound was selected for audits is
shown. The frequency of audits
conducted at RCRA trial burn tests on a
quarter/calendar year basis since 1984 is
shown in Figure 1. It appears from Figure
1 that the frequency of audits has
increased since October 1986, due to the
mandatory audit requirement included in
the VOST method published in SW 8462.
Seven of the 27 compounds have been
found to be more popular for
performance audits. These seven
compounds are: carbon tetrachloride,
chloroform, perchloroethylene, vinyl
chloride, trichloroethylene. benzene, and
toluene. Of the 179 audits completed,
151 are by the VOST method, 20 with
Tedlar bags, 1 with glass bulbs, 7 by
direct injection, and 1 audit is unknown.
The majority of the audits employed
GC/MS for analysis and only a few used
GC with a specific detector. It is very
interesting to note that the auditee results
for the VOST method are usually within
the ±50 percent accuracy limit stated in
the VOST protocol.
Stability Studies
An ideal calibration standard or audit
material should be stable over its total
time of usage. Such standards or
materials may be considered stable if the
results of reanalyses over time fall within
the 95% confidence limits of the
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Table 1. Auditing POHC Measurements"
Group 1 Compounds
Carbon tetrachloride
Chloroform
Group II Compounds
Trichloroethylene
1 ,2-dichloroethane
Group III Compounds
Vinylidene chloride
1 ,1 ,2-trichloro-l ,2,2-trifluoroethane
Group IV Compounds
Acrylonitrile
1 ,3-Butadiene
Perchloroethylene
Vinyl chloride
Benzene
1,2-dibromoelhane
Acetonitrile
Trichlorofluoromethane (F-11)
Dichlorodifluoromethane (F-12)
Bromomethare
Methyl ethyl ketone
1,1,1-trichloroethane
(F-113)
1,2-dichloro-1,1,2,2,-
tetrafluoroethane (F-114)
Acetone
1,4-Dioxane
Chlorobenzene
Toluene
Pyridine*"
Ethylene oxide*"
Methylene chloride
Propylene oxide*"
Ortho-xylene
Group I Ranges
Group II Ranges
Group III Ranges
Group IV Ranges
7 to 90 ppb
90 to 430 ppb
430 to 10,000 ppb
7 to 90 ppb
90 to 430 ppb
7 to 90 ppb
90 to 430 ppb
7 to 90 ppb
430 to 10,000 ppb
"All gas standards are in a balance gas of nitrogen
"The concentration of pyridine is not certified due to instability problems.
""The concentration of this compound in the 7 to 90 ppb range cylinders is not certified due to stability problems. Compounds in the 430 to 10,000 ppb
range are found to be stable.
combined uncertainty for the preparation
and analysis of the analyte
concentrations.
To ensure that the concentration of
each standard is periodically analyzed for
stability, a two-tier stability assessment is
conducted. In the first tier, on each
standard, the commercial gas
manufacturer conducts a minimum of two
analyses that are separated by at least 30
days. These analyses were performed to
verify that the components in the cylinder
were stable at the manufacturing facility
before shipment to RTI. The second tier
stability assessment involves the periodic
reanalysis at RTI. Once a gas standard is
received from the gas manufacturer, it is
analyzed as soon as possible, then
reanalyzed at 2, 6, and 12 months and
annually thereafter to determine any
change in the gas mixtures. All analyses
are performed by gas chromatography
(GC) with flame ionization (FID) and/or
electron capture detector (ECD).* The
"Currently, National Institute of Standards and
Technology (NIST) traceable standards developed
and characterized by NIST are being used for
calibration and a similar NIST standard cylinder
mixture is used for Quality Control during all the
analyses
analysis procedures and the stability data
obtained to date for all of the ppb level
organic cylinder gases are summarized
and published in the project report3. An
examination of the stability data for many
of the organics in the ppb level cylinder
gases show the results varied by less
than 10 percent over a one to five year
period. A gas standard is not available for
auditing purposes until the 2-month RTI
analysis is completed. If the compounds
are not stable during that period, those
compounds are not recommended for
audits. It appears from the long-term
stability study, that all the organics tested
(with the exception of ethylene oxide and
propylene oxide at 10 ppb level) are
stable enough to be used as reliable
audit materials.
Summary and Conclusions
Compressed gas cylinders containing
27 gaseous volatile organic compounds
at parts-per-billion levels have been used
successfully in audits to assess the
accuracy of measurement systems,
especially those used during hazardous
waste trial burn tests. The 27 gaseous
volatile organic compounds were
selected on the basis of the anticipated
needs of US EPA's Office of Solid Waste
and Office of Air Quality Planning and
Standards.
Stability studies indicate that all of the
organic compounds tested (with the
exception of ethylene oxide and
propylene oxide at the 10 ppb level) are
stable enough to be used as reliable
audit materials. One hundred twenty nine
performance audits have been initiated
(through September 1989) to assess the
accuracy of POHC measurement
systems used during hazardous waste
trial burn tests. Audit results have
generally been within ± 50 percent of the
RTI measured concentrations.
References
1. D. J. von Lehmden, "Program
Strategies for Standards
Development for Hazardous Waste
Incineration", presented at the
ASTM Conference on Recent
Developments in Monitoring
Methods for Toxics in the
Atmosphere, July 27-31, 1987,
Boulder, Colorado.
2. Volatile Organic Sampling Train,
Method 0030, SW-846 Manual
(Test Methods for Evaluating Solid
Waste, Physical/Chemical
Methods), 3rd Edition, available
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Quarter/Calendar Year Audit Initiated
Figure 1. Audits conducted in RCRA trial bums.
from the Superintendent of
Documents, U.S. Government
Printing Office, Washington, DC
20402, Document Number 955-
001-00000-1.
3. V R. Bryant, G. B. Howe, S. B.
Tompkins, and R. K. M. Jayanty,
"Stability of Parts-Per-Billion
Hazardous Organic Cylinder
Gases and Performance Audit
Results of Source Test and
Ambient Air Measurement
Systems" Status Report #6,
Research Triangle Institute,
October, 1989.
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R. K. M. Jayanty, S. B. Tompkins, V. R. Bryant, and G. B, Howe are with Research
Triangle Institute, Research Triangle Park, North Carolina 27709.
Darryl J. von Lehmden is the EPA Project Officer (see below)
The complete report, entitled "Annual Report on Performance Audit Results for
POHC Testing During RCRA Trial Burns-Status Report #2," (Order No.
PB90-164 831/AS; Cost: $17.00, 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 Officer can be contacted at:
Atmospheric Research and Exposure Assessment Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S3-90/006
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