For presentation at the International Conference on Incineration and Thermal Treatment
Technologies, May 10-14, 1999, Orlando, FL.
Emissions of Polychlorinated Riphenyls as
Products of Incomplete Combustion from Incinerators
P.M. Lemieux, C.W. Lee, J.D. Kilgroe, J.V. Ryan
U.S. Environmental Protection Agency
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
ABSTRACT
Polychlorinated biphenyls (PCBs) have been widely used in the past as industrial chemicals,
particularly as additives in electrical transformer cooling oil. Growing evidence of PCBs' role
as a persistent, bioaccumulative, human carcinogen has led to the banning of the production and
use of PCBs as an industrial chemical in major industrialized countries including the United
States. PCBs, however, are still being released into the environment as an unwanted by-product
of combustion processes, particularly those associated with chlorinated materials. A subset of
PCBs, the coplanar isomers, exhibit biological activity similar to that of polychlorinated dibenzo-
/;-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs), a widely recognized by-product
of combustion processes. Significant progress has been made over the last 10 years investigating
the fundamental PCDD/PCDF formation mechanisms, while emissions of PCBs from
combustion devices have not been extensively investigated. This paper presents background
information on some of the combustion sources that generate PCBs.
1

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INTRODUCTION
A number of persistent organic pollutants (POPs) are of national and international concern due to
their persistence, their mobility, their ability to bioaccumulate, and their potential impacts on the
health of humans, wildlife, and fish. Much of this concern involves 12 chemical classes that
include polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and -furans
(PCDDs/PCDFs), and pesticides such as dichlorodiphenyltrichloroethanc (DDT), chlordane, and
heptachlor [Wania and MacKay, 19961. The three chemical classes that are perhaps of greatest
concern are PCDDs, PCDFs, and PCBs [U.S. EPA, 1994; U.S. EPA, 1997].
Formation and control of PCDDs/PCDFs from combustion sources have been a public
environmental health concern because of reputed carcinogenic, teratogenic, endocrine-
disrupting, and persistent and accumulative behavior of these compounds in biological systems.
Of the 208 tetra-octa CDD/CDF isomers, 17 (those substituted in the 2,3,7,8 positions) are
recognized for their toxicity.
From the 1940's to the 1970's, PCBs were widely used commercial chemicals. They were used
primarily as heat transfer fluids and as pesticides. At one time, eight mixtures of PCBs were
sold in the U.S. under the trade name Aroclor. Many other mixtures were manufactured
elsewhere. In 1977 Congress passed the Toxic Substances Control Act (TSCA), providing
EPA with broad "cradle-to-grave" regulatory authority for almost all existing and new chemicals
manufactured, imported, or used in the U.S. [Shifrin and Toole, 1998J. In January 1978, EPA
banned the manufacture, processing, distribution, or use of any PCBs in any manner other than
entirely enclosed. However, the previous manufacture and use of PCBs produced a negative
legacy. In 1991, EPA's Superfund Office estimated that PCBs were a major contaminate,
accounting for about 34 million cubic yards of material at 20 % of the sites on the National
Priorities List [Shifrin and Toole. 1998].
9

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Certain polychlorinated biphenyl (PCB) isomers exhibit similar toxic effects as PCDDs/PCDFs.
PCBs substituted with zero or one chlorine atom in the 2,2' or 6,6' (ortho) position on the phenyl
ring and one or more incta (m) or para (p) chlorines on each ring (see Figure 1) can assume a
planar configuration, leading to a molecule that is similar in structure and orientation to 2,3,7,8-
tctrachlorodibenzo-/?-dioxin (TC.DD). These coplanar PCBs are also termed "dioxin-like" PCBs.
2,3,7,8-Tfitrachlorodiben?o-,'>cJioxin	3,3\4,4',0,5'-Hoxachlorobiphenyl
Figure 1. PCBs and Dioxin Structure
Similar to PCDDs/PCDFs, each coplanar PCB isomer has been assigned a toxic equivalency
factor (TKF) relative to 2,3,7,8-TCDD [Ahlborg et al.. 1994]. which has been arbitrarily assigned
a value of 1 as shown in Table 1 [NATO, 1988]. By summing the products formed by
multiplying the concentrations of the various molecules for which a TEF has been assigned by its
respective TEF, a toxic equivalency (TEQ) concentration is derived. The TEQ is used as an
estimate of the total dioxin-like toxicity of a complex mixture. Human exposure to dioxin-like
PCBs in the environment has been suggested to be very significant in a recent review [Alcock et
al., 1998], which showed that the human body burden of dioxin-like PCBs is between 50 and 70
% of the total TEQ, based on published European and North American studies. The review also
suggested that dioxin-like PCBs dominate the total TEQ (up to 90% total TEQ) of several major
food sources such as fish, oils, and fats consumed by humans.
Efforts to control the risks from PCBs have concentrated on exposure related to the manufacture
and use of PCBs, with major emphasis on manufacturing process residues and wastewater
discharges. It is generally believed that emission of PCBs from combustion sources results
primarily from the incomplete destruction of wastes containing PCBs [U.S. EPA, 1997J. Few
people, except combustion experts or individuals in the incineration industry, understand that
PCBs can be synthesized during the combustion process via gas-phase or heterogeneous
reactions.
3

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Table 1. Toxic Equivalency Factors for PCBs [Ahlborg et al, 1994]
Type
Congener

TEF

IUPAC No.
Structure

Non-ortho
77
3,3\4,4'-TCB
0.0005

126
3,3',4,4',5-PeCB
0.1

169
3,3\4.4',5,5'-HxCB
0.01
Mono-ortho
105
2,3,3\4,4'-PeCB
0.000 i

114
2,3,4.4',5-PeCB
0.0005ah

118
2,3'4,4'.5-PeCB
0.0001

123
2',3,4,4',5-PeCB
0.0001

156
2,3,3',4,4',5-HxCB
0.0005b

157
2,3,3\4.4\5'-HxCB
0.0005b

167
2,3\4.4',S,5'-HxCB
0.0000 V

189
2,3,3\4,4',5,5'-HpCB
o.ooor
Di-ortho
170
2,2',3,3',4.4\5-HpCB
0.0001s

180
2,2',3,4.4\5,5'-HpCB
o.oooo r
a - Based on very limited data
b - IUPAC 114, 156, and 157 are expected to have similar TEF values based on similar
responses. Although the data are limited, the determination of TEFs for these congeners is
supported by their structural similarity.
There arc very little available data reporting emissions of PCBs from combustion sources, since
PCBs were extensively used as industrial chemicals, and their air emissions as trace combustion
by-products were largely ignored [Brown et al., 1995]. Combustion sources in the U.S. do not
typically require PCB emissions testing. Only in the Netherlands was a national inventory of
dioxin-likc PCB sources developed [Alcock et al., 1998]. Based on these limited data. PCBs
appear to contribute significantly to the total TEQ emissions from combustion sources. For
some sources, such as municipal waste combustors (MWCs), PCBs contributed a relatively small
fraction (<5%) of the TEQ [Alcock et al., 1998]. This observation on MWCs was duplicated by
some Japanese researchers [Kawakami et al., 1993]. For other sources, however, such as cement
kilns, PCBs contributed up to 60% of the TEQ [Alcock et al., 1998]. Metal reclamation and
sintering plants have also been identified as an important source of coplanar PCBs [Boers et al.,
1994]. PCB TEQs from combustor emissions appear to be dominated by the PCB-126 congener,
one of the non-ortho PCBs, which also has the highest TEF (0.1) of all PCBs.
4

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The largest body of PCB combustor emissions data from North America exists from some
hazardous waste incinerator (HWI) and cement kiln trial burns performed under the Resource
Conservation and Recovery Act (RCRA), from EPA's HWI database [U.S. EPA, 1996], and
from some MWCs that were sampled during Environment Canada/U.S. EPA's National
Incinerator Testing and Evaluation Program [Finkclstein and Klicius, 1994]. Recently
developed RCRA guidance documents supporting current HWI regulations specify that certain
sources must measure PCBs during emission tests to support risk assessments as part of the
permitting process [U.S. EPA, 1998a; U.S. EPA, 1998b].
The limited available data suggest that PCBs may be formed by the same types of reactions that
produce PCDDs/PCDFs [Schoonenboom et al., 1995]. PCDDs/PCDFs are generally believed to
be formed via several proposed mechanisms: gas-phase formation [Weber and Hagcnmaier,
1999]; heterogeneous formation from organic precursors [Gullett et al., 1994]; and de novo
synthesis from flyash-bound carbon [Stieglitz, 1998]. Both of these latter mechanisms involve
heterogeneous reactions with flyash-bound metals (such as copper) serving as catalytic sites for
reactions involving various carbon-containing species in the gas and/or solid phases. These
reactions occur downstream of the high temperature combustion zone at temperatures ranging
from 250 to 700 °C. The formation reactions from organic precursors are believed to occur
relatively quickly while the flue gases pass through the downstream regions of the combustion
device, with reaction times on the order of seconds, while the de novo synthesis is believed to
occur slowly, with reaction times on the order of minutes or hours, while the flyash is held up in
the particulate control devices.
If both PCBs and PCDDs/PCDFs are generated through similar mechanisms, it would be
expected that emissions of PCBs should correlate with emissions of PCDDs/PCDFs. This
correlation would be expected to be very strong if there were a common rate-limiting step
involved in the formation of both PCBs and PCDDs/PCDFs. This paper will examine that
hypothesis.
5

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APPROACH
PCB and PCDD/PCDF measurement data were gathered from various combustion sources in the
literature and from risk assessment, trial burn, and risk burn reports from EPA's Regional
Offices as well as from EPA's Hazardous Waste Combustor Database [U.S. EPA, 1996]. All
data were placed into units of nanograms per dry standard cubic meter, corrected to 7 % oxygen
(02), with the exception of the Environment Canada data, which were corrected to 12 % carbon
dioxide (C02). All PCB data reflect total PCBs, and PCDD/PCDF data reflect the total of all
tetra through octa chlorinated congeners of PCDD + PCDF. At this point, no TEQ calculations
have been made since sufficient information was not available to make those calculations for all
of the data sets.
The data are summarized in Table 2. Sources for the data in Table 2 included test points from
two different wet process cement kilns, data from several IIWIs burning hazardous waste (HW),
from a facility burning chemical demilitarization wastes (nerve gas), from a facility
decontaminating soil at a Superfund site, and from several different types of MWCs burning
municipal solid waste (MSW) or refuse-derived fuel (RDF). Samples taken at similar operating
conditions for a single facility were averaged into a single entry in Table 2. However, if multiple
operating conditions were sampled during a parametric test or trial burn, then each discrete
operating condition was reported as an entry in Table 2. Also note that some of the HWIs
included some quantity of PCB in the initial feed. The presence of PCB in the feed was not
corrected for in any way.
6

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Table 2. PCB and PCDD/PCDF Data
Facility Type
Feed
PCBs
in
Feed
Total Total PCBs
PCDD/PCDF (ng/dscm)
(ng/dscm)
Reference
Cement Kiln (Wet)
coal/ hazwaste
N
8.65E-01
9.98E+02
Weston, 1997
Cement Kiln (Wet)
coal/ hazwaste
N
1.17E+00
1.60E+03
Weston, 1997
HWI (Rotary Kiln)
soil
N
2.46E+00
1.12E+02
Midwest Research, 1997a
HW1 (Rotary Kiln)
soil
N
3.45E+00
6.96E+01
Midwest Research, 1997b
HWI (Rotary Kiln)
hazwaste
Y
6.78F.+02
9.39E+02
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
Y
7.28E+02
3.68E+03
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
Y
2.94 E+02
5.70E+02
US EPA, 1996
HWI (Liquid
hazwaste
Y
5.41B+02
1.47E+04
US EPA, 1996
Injection)





HWI (Liquid
hazwaste
Y
5.53E+02
1.46E+04
US EPA, 1996
Injection)





HWI (Rotary Kiln)
demil
N
l.OOE-tOO
1.70E+01
US EPA, 1996
HWI (Liquid
hazwaste
N
6.00E+00
5.I3E+02
US EPA, 1996
Injection)





HWI (Rotary Kiln)
hazwaste
N
1.00F+00
2.10H+01
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
Y
1.00E+0I
1.09E+03
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
Y
2.60E+01
1.92E+03
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
N
5.70E+01
4.32E+02
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
N
6.40E+01
1.73E+02
US EPA, 1996
HWI (Rotary Kiln)
hazwaste
N
2.60E+0I
4.03E+02
US EPA, 1996
Cement Kiln (Wet)
coal/ hazwaste
N
1.22H+01
1.74E+03
Radian, 1998
Cement Kiln (Wet)
coal/ hazwaste
N
2.32E+01
1.35E+03
Radian, 1998
Cement Kiln (Wet)
coal/ hazwaste
N
2.72E+01
1.45E+03
Radian, 1998
HWI (Rotary Kiln)
demil
i\
6.90E-03
5.40E+00
US EPA, 1998c
HWI (Moving Grate)
demil
N
1.16E-01
1.29E+01
US EPA, 1998d
MWC (Modular)
MSW
N
2.63E+02
5.80E+01
Environment Canada, 1985
MWC (Modular)
MSW
N
1.57E+02
ND
Environment Canada. 1985
MWC (Modular)
MSW
N
2.21E+02
L26E+02
Environment Canada, 1985
MWC (Stoker)
RDF
N
7.01E-01
1.19E+01
Environment Canada, 1994
MWC (Stoker)
RDF
N
1.49E+00
1.91H+01
Environment Canada, 1994
MWC (Mass Burn)
MSW
N
1.67E+02
4.30E+03
Environment Canada, 1987
MWC (Mass Bum)
MSW
N
6.33Ii+01
3.00E+03
Environment Canada, 1987
MWC (Mass Burn)
MSW
N
1.56E+02
4.90E+03
Environment Canada, 1987
MWC (Mass Burn)
MSW
N
5.97E+02
7.0011+03
Environment Canada, 1987
MWC (Mass Bum)
MSW
N
5.25E+02
1.70E+03
Environment Canada, 1987
MWC (Stoker)
MSW
N
4.50E+03
3.60E+02
Kawakami et al., 1993
MWC (Stoker)
MSW
N
1.81E+03
L30E+02
Kawakami et al., 1993
MWC (Stoker)
MSW
N
6.70E+02
1.90E+02
Kawakami et al., 1993
MWC (Stoker)
MSW
N
4.00E+02
1.10E+02
Kawakami et al., 1993
ND - none detected
7

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RESULTS
PCBs were, for most cases, emitted at higher levels than PCDDs/PCDFs. The data from Table 2
are presented in Figure 2. grouped according to three general facility types: cement kilns, HWIs,
and MWCs. There appears to he a very distinct trend with increasing PCB emissions as
PCDD/PCDF emissions increase. This trend appears to be independent of the facility type,
although the data from the cement kilns are found in the upper area of the cluster of data points.
The MWC facility data fit in quite well with the HWI data. Overall, PCB emissions exceeded
PCDD/PCDF emissions by approximately a factor of 20, and this trend appeared to hold over
five orders of magnitude in PCDD/PCDF emissions.
100000
10000
E
o
1000
O)
C
C/)
CD
O
^ 100
3
o
10
1
0.001 0.01 0.1	1	10 100 1000 10000
Total PCDDs/PCDFs (ng/dscm)
Figure 2. PCDDs/PCDFs vs PCBs
¦ Cement Kilns
• Hazardous Waste Incinerators
A Municipal Waste Combustors
• •
* A
~
• A
8

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A study in Finland [Kiviranta ct al., 1999] compared levels of PCDD/PCDF TEQs and PCBs in
human milk and found a similar trend, although the slope of the line was different. In the
Finnish study, total PCBs were approximately three orders of magnitude higher than the
PCDD/PCDF TEQs. Given that, depending on the source, total PCDDs/PCDFs are nominally a
factor of 100 greater than the TEQ, this trend is strikingly similar. The high correlation
coefficient (R7 = 0.93) suggested the hypothesis that the sources of PCDDs/PCDFs and PCBs are
the same in the Finnish study.
CONCLUSIONS
Data were gathered from various field samples where both PCDDs/PCDFs and PCBs were
measured. PCBs were found in the stack in most cases, both in facilities that had PCBs initially
in the feed and in those that did not have any PCBs in the feed. Stack concentrations of PCBs
were generally higher than stack concentrations of PCDDs/PCDFs, and an apparent trend was
observed. This trend was consistent across several orders of magnitude in PCDD/PCDF
concentration as well as across several different facility types and feed stocks.
This trend suggests that the same fundamental mechanisms that contribute to the formation of
PCDDs/PCDFs may result in formation of PCBs. It also similarly suggests that control
strategies intended to reduce emissions of PCDDs/PCDFs may also serve to control PCBs.
Although PCBs do not have as high a TEF as 2,3.7.8-TCDD, some of the PCBs have significant
TEFs, and since they may be present at concentrations much higher than PCDDs/PCDFs, PCBs
may contribute significantly to the overall TEQ for some sources.
ACKNOWLEDGMENTS
The authors would like to acknowledge the assistance of the following people from EPA's Office
of Solid Waste and Regional Offices in locating the field data: Frank Behan, Stacy Braye, Gary
Gross, Bob Holloway, George Peters, and Gary Victorine.
9

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REFERENCES
Ahlborg, U.G., G.C. Becking, L.S. Birnbaum, A. Brouwer, J.J.G.M. Derks, M. Feeley, G. Golor,
A. Hanberg, J.C. Larsen, A.K.D. Liem, S.H. Safe, C. Schlatter, F. Waern, M. Younes, and H.
Yrjanheikki, "Toxic Equivalency Factors for Dioxin-Like PCBs," Chemosphere, Vol. 28, No. 6,
pp. 1049-1067, 1994.
Alcock, R.E., P.A. Behnisch, K.C. Jones, and H. Hagenmaier, "Dioxin-like PCBs in the
Environment—Human Exposure and the Significance of Sources," Chemosphere, Vol. 37, No.
8, pp. 1457-1472, 1998.
Boers, J.P., E.W.B. de Leer, L. Gramberg, and J. de Koning, "Levels of coplanar PCB in flue
gases of high temperature processes and their occurrence in environmental samples," Fresenius
J. Anal. Chem., 348: 163-166, 1994.
Brown, J.F., Jr., G.M. Frame II, D.R. Olson, and J.L Webb, "The Sources of the Coplanar
PCBs," Organohalogen Compounds, Vol. 26, pp. 427-430, 1995.
Environment Canada, "The National Incinerator Testing and Evaluation Program: Two-stage
Combustion (Prince Edward Island)," Report EPS 3/UP/l, September 1985.
Environment Canada, "The National Incinerator Testing and Evaluation Program: The
Combustion Characterization of Mass Burning Incinerator Technology, Quebec City," Report
IP-82, December 1987.
Environment Canada, "The National Incinerator Testing and Evaluation Program: The
Environmental Characterization of Refuse-Derived Fuel (RDF) Combustion Technology,"
Report EPS 3/UP/l, December 1994.
Finkelstein, A., and R.D. Klicius, "National Incinerator Testing and Evaluation Program: The
Environmental Characterization of Refuse-derived Fuel (RDF) Combustion Technology, Mid-
Connecticut Facility, Hartford, Connecticut," FPA-600/R-94-140 (NTIS PB96-153432),
December 1994.
Gullett, B.K., P.M. Lemieux, and J.E. Dunn. "Role of Combustion and Sorbent Parameters in
Prevention of Polychlorinated Dibenzo-p-Dioxin and Polychlorinated Dibenzofuran Formation
During Waste Combustion " Environ. Sci. and Tech., Vol. 28, No. 1, pp. 107-118, 1994.
Kawakami, I., Y. Matsuzawa, M. Tanaka, S. Sakai, and M. Hiraoka, "Emission Level of Co-
PCBs from MSW Incinerators," Organohalogen Compounds, Vol. 11, pp. 375-380, 1993.
Kiviranta, H., R. Purkunen, and T. Vartiainen, "Levels and Trends of PCDD/Fs and PCBs in
Human Milk in Finland," Chemosphere, Vol. 38, No. 2, pp. 311-323, 1999.
Midwest Research Institute, "Test Report for Risk Burn No. 1 on the Drake Chemical Superfund
Site's Mobile On-site Hazardous Waste Incinerator, Volume 1—'Technical Report (Draft)," MRI
Project No. 3620-18, March 26, 1997a.
Midwest Research Institute, "Test Report for Risk Burn No. 2 on the Drake Chemical Superfund
Site's Mobile On-site Hazardous Waste Incinerator, Volume 1—Technical Report (Draft)." MRI
Project No. 3620-28, April 8, 1997b.
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NATO. "International Toxicity Hquivalcnt Factors (TEFs) Method of Risk Assessment for
Complex Mixtures of Dioxins and Related Compounds/' Report No. 176, Brussels: North
Atlantic Treaty Organization, 1988.
Radian International, "Lafarge Corporation, Paulding, Ohio, August 1998 Trial Burn Report,"
August 1998.
Schoonenboom, M.H., P.C. Tromp, and K. Olie, "The Formation of Coplanar PCBs, PCDDs,
and PCDFs in a Fly Ash Model System," Chemosphere, Vol. 30, No. 7, pp. 1341-1349, 1995.
Shifrin, N.S., and A. P. Toole, "Historical Perspective on PCBs," Environmental Engineering
Science, Volume 15, Number 3, 1998.
Stieglitz, L., "Selected Topics on the De Novo Synthesis of PCDD/PCDF on Fly Ash,"
Environmental Engineering Science, Vol. 15, No. 1, 1998.
U. S. EPA, "Health Assessment Document for 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)
and Related Compounds," Vol. 1, EPA/600/BP-92/001a (NTIS PB94-205465) (external review
draft), Office of Health and Environmental Assessment, Washington, DC, June 1994.
U.S. EPA, "Updated Hazardous Waste Combustor Database," Office of Solid Waste,
Washington, DC, December 1996.
U.S. EPA, "Deposition of Air Pollutants to the Great Waters: Second Report to Congress,"
EPA-453/R-97-011, Office of Air Quality Planning and Standards, Research Triangle Park , NC,
June 1997.
U.S. EPA (1998a). "Human Health Risk Assessment Protocols for Hazardous Waste Combustion
Facilities," EPA-530-D-98-001A, Office of Solid Waste, Washington, DC, July 1998.
U.S. EPA (1998b), "Guidance on Collection of Emissions Data to Support Site-Specific Risk
Assessments at Hazardous Waste Combustion Facilities," EPA-530-D-98-002, Office of Solid
Waste, Washington, DC, August 1998.
U.S. EPA (1998c), "GB Trial Burn Report for the Trial Burn of the MPF Incinerator, Johnston
Atoll Chemical Agent Disposal System (JACADS) Johnston Island," (submitted to USEPA
Region 9 by Program Manager for Chemical Demilitarization, Aberdeen Proving Ground. MD),
July 1998.
U.S. EPA (1998d), "GB Trial Bum Report for the Trial Burn of the DFS Incinerator, Johnston
Atoll Chemical Agent Disposal System (JACADS) Johnston Island," (submitted to USEPA
Region 9 by Program Manager for Chemical Demilitarization, Aberdeen Proving Ground. MD),
July 1998.
Wania, F., and D. MacKay, "Tracking the Distribution of Persistent Organic Pollutants,"
Environ. Sci, TechnoL, Vol. 30, No. 9, 1996.
Weber, R., and H. Hagcnmaier, "Mechanism of Formation of Polychlorinated Dibenzo-p-dioxins
and Dibcnzofurans from Chlorophenols in Gas-Phase Reactions," Chemosphere, Vol. 38, No. 3.
pp 529-549, 1999.
Weston, R.F., Keystone Cement Company Source Emissions Test Report, February 1997.
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vD,JDT nTn D ,nQ TECHNICAL REPORT DATA
J\ Jtv.vl 1\I . x\ .1 ~ ± *±UJ (Please read Instructions on the reverse before completing)
	
I.RCPOnTNO. 2.
EPA 600/A-99/051
3. RECI
4. TITLE AND SUBTITLE
Emissions of Polychlorinated Biphenyls as Products
of Incomplete Combustion from Incinerators
5. RCPORT DATE
6. PERFORMING ORGANIZATION CODE
7-authoris) P-I/emieuX( c.W.Lee, J. D.Kilgroe, and
J- V. Ryan
8. PERFORMING ORGANIZATION RCPORT NO.
9. PERFORMING ORGANIZATION NAME AND AOORESS
See Block 12
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
NA (Inhouse)
12. SPONSORING AGENCY NAME ANO AOORESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Published paper; 10/98-3/99
14. SPONSORING AGENCY CODE
EPA/600/13
15. supplementary notes^pp(-jj project officer is Paul M. Lemieux, Mail Drop 65, 919/
541-0962. For presentation at International Conference on Incineration and Thermal
Treatment Technologies, Orlando, FL, 5/10-14/99.
16. abstract r^Q pape r diScusses emissions of polychlorinated biphenyls (PCBs) as pro-
ducts of incomplete combustion from incinerators. PCBs were used widely as indus-
trial chemicals, particularly as additives in electrical transformer cooling oil.
Growing evidence of PCBs' role as a persistent, bioaccumulative, human carcino-
gen led to the banning of their production and use as an industrial chemical in major
industrialized countries including the U. S. However, PCBs arc still being released
into the environment as an unwanted by-product of combustion processes, particu-
larly those associated with chlorinated materials. A subset of PCBs, coplanar iso-
mers, exhibit biological activity similar to that of polychlorinated dibenzo-p-
dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs), a widely recognized by-
product of combustion processes. Significant progress has been made over the last
10 years investigating the fundamental PCDD/PCDF formation mechanisms, while
emissions of PCBs from combustion devices have not been extensively investigated.
The paper presents background information on some of the combustion sources that
generate PCBs.
17. KEY WOROS AND OOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TF.RMS
c. COSATI Field/Group
Pollution
Chlorine Aromatic Compounds
Biphenyl
Emission
Incinerators
Combustion
Carcinogens
Pollution Control
Stationary Sources
Polychlorinated Biphe-
nyls
Products on Incomplete
Combusti on
Coplanar Isomers
13	B
07C
14	G
21B
06 E
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
11
20. SECURITY CLASS (This pa^e)
Unclassified
??. PRICk
!
LPA form 2220-1 (9->3)

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