Unl*d States
Em*
Control Technology Center
EPA-600/R-92-127
July 1992
MUTAGENICITY OF EMISSIONS
FROM THE SIMULATED OPEN BURNING
OF SCRAP RUBBER TIRES
control
technology center
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EPA REVIEW NOTICE
This report has been reviewed by the Control Technology Center (CTC) established by the
Office of Research and Development (ORD) and the Office of Air Quality Planning and
Standards (OAQPS) of the U.S. Environmental Protection Agency (EPA), and has been
approved for publication. Approval does not signify that the comments necessarily reflect the
views and policies of the U.S. EPA nor does mention of trade names or commercial products
constitute an endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/R-92-127
July 1992
Mutagenicity of Emissions from the
Simulated Open Burning of Scrap Rubber Tires
Prepared by:
Paul M. Lemieux
U.S. Environmental Protection Agency
Air and Energy Engineering Research Laboratory
Research Triangle Park, NC 27711
David M. DeMarini
U.S. Environmental Protection Agency
Health Effects Research Laboratory
Research Triangle Park, NC 27711
Prepared for:
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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ABSTRACT
Discarded automobile tires have become a serious health concern, largely because the
growing number of stockpile fires has focused attention on the potentially harmful products of
incomplete combustion (PICs) emitted into the atmosphere from uncontrolled burning of scrap
tires. This report describes a follow-up to a small-scale combustion study that was designed to
collect, identify, and quantify the products emitted during the simulated open combustion of
scrap tires. During the previous study, it was found that total estimated emissions of
semi-volatile organics ranged from 10 to 50 g/kg of tire material burned. Mono- and
polyaromatic hydrocarbons were the predominant emission products identified. For the
follow-up study described in this report, the extracts from this study were subjected to
bioassay-directed fractionation to determine mutagenic potencies of the extracts. The results
from these bioassay studies were then compared to data from other conventional combustion
sources to give an indicator of the relative potencies of the emissions from uncontrolled burning
of tires. The fractionated extracts were then subjected to further GC/MS analysis to determine
the 'classes of compounds giving the highest mutagenic potencies. In addition, a real world
sample from an actual tire burn was subjected to the same bioassay analyses so as to determine
the relevance of the small-scale simulations, performed in the EPA's Open Burning Facility in
Research Triangle Park, to actual field samples taken from a full-scale tire fire.
11
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PREFACE
The CTC was established by EPA's Office of Research and Development (ORD) and Office
of Air Quality Planning and Standards (OAQPS) to provide technical assistance to state and
local air pollution control agencies. Three levels of assistance can be accessed through the CTC.
First, a CTC HOTLINE has been established to provide telephone assistance on matters relating
to air pollution control technology. Second, more in-depth engineering assistance can be
provided when appropriate. Third, the CTC can provide technical guidance through
publication of technical guidance documents, development of personal computer software, and
presentation of workshops on control technology matters.
The technical guidance projects, such as this one, focus on topics of national or regional
interest that are identified through contact with state and local agencies. In this case, the CTC
became interested in examining pollutants emitted from open air tire burning, and providing
qualitative and semi-quantitative estimates of the emissions. These simulated open burning
tests were completed in 1989 and the final report titled "Characterization of Emissions from the
Simulated Open Burning of Scrap Tires" was published as EPA report EPA-600/2-89-054. The
shady discussed in this report is a follow-up to the original open burning study, where the
previously sampled organic extracts were subjected to bioassays to determine mutagenic
potencies of the extracts, then gas chromatography/mass spectroscopy (GC/MS) analysis to
determine which classes of compounds accounted for the mutagenic activity.
This report consists of two parts. Part 1 summarizes the experiments and findings from the
previous study. Part 2 examines the bioassay analyses on the extracts acquired from the
previous study, on extracts acquired from a full-scale tire fire, and the GC/MS analyses of the
most mutagenic fractions from the bioassay-directed fractionation experiments.
in
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ACKNOWLEDGMENTS
The initial tire burning study was performed by Jeff Ryan, Rick Rinehart, and Ken Krebs of
Acurex Corp. under EPA Contract No. 68-02-4701, Task 88-41, under the direction of EPA Task
Officer Paul Lemieux. The authors would like to thank Douglas W. Bryant from McMaster
University, Hamilton, Ontario, Canada, for providing the samples from the Hagersville,
Ontario, tire fire. The authors would also like to thank Ron W. Williams and Lance R. Brooks of
Environmental Health Research and Testing (EPA Contract No. 68-D1-0148) for their
contributions to the HPLC fractionation studies.
IV
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TABLE OF CONTENTS
ABSTRACT ii
PREFACE iii
ACKNOWLEDGMENTS iv
LIST OF FIGURES vi
LIST OF TABLES vi
1. SUMMARY OF PREVIOUS WORK 1
1.1 INTRODUCTION 1
1.2 EXPERIMENTAL APPROACH 3
1.2.1 Project Description 3
1.2.2 Experimental Apparatus 3
1.2.2.1 Burn Hut 3
1.2.2.2 Sample Shed 4
1.2.2.3 HAPML 5
1.3 DATA, RESULTS AND DISCUSSION 6
1.3.1 Burn Rate Results 6
1.3.2 CEMData 7
1.3.3 Volatile Organic Emission Data 8
1.3.4 Semi-Volatile Organic Emission Data 11
1.3.5 Particulate Emission Data 14
1.3.6 Airborne Metals Data 15
1.4 SUMMARY AND CONCLUSIONS 16
2. MUTAGENICITY OF EFFLUENT FROM OPEN TIRE BURNING 18
2.1 INTRODUCTION 18
2.2 EXPERIMENTAL PROCEDURES 19
2.3 DATA, RESULTS AND DISCUSSION 20
2.3.1 Mutagenic Potency of Organics 20
2.3.2 Mutagenic Emission Factors 24
2.3.3 Bioassay-Directed Fractionation and Chemical Analysis 27
2.3.4 Comparison of Simulated Tire Burn to Real-World Tire Burn. 35
2.4 SUMMARY AND CONCLUSIONS 40
REFERENCES 42
APPENDIX A: QUALITY ASSURANCE 45
A-l. Sample Preparation 45
A-2. Gas Chromatography 45
A-3. High Pressure Liquid Chromatography 46
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LIST OF FIGURES
Figure 1-1. Diagram of Burn Hut 4
Figure 1-2. Locations of Required Test Equipment 4
Figure 1-3. Diagram of Sampling Systems Used 5
Figure 1-4. Burn Rate Vs. Elapsed Time 6
Figure 1-5. CEM Concentrations Vs. Elapsed Time 7
Figure 2-1. Mutagenic Potencies of XAD Extracts 21
Figure 2-2. Mutagenic Potencies of Particulate Filter Extracts 22
Figure 2-3. Mutagenic Emission Factors of Combustion Emissions in
Salmonella Strain TA98 (+S9) 26
Figure 2-4. HPLC Chromatogram, Day 1 Results 28
Figure 2-5. HPLC Chromatogram, Day 2 Results 29
Figure 2-6. Salmonella TA98 Mutagram, Day 1 Results 31
Figure 2-7. Salmonella TA98 Mutagram, Day 2 Results 32
Figure 2-8. Salmonella TA98 Mutagram, Composite Sample 33
Figure 2-9. Salmonella TA98 Dose-Response Curves, Composite Sample.. 36
Figure 2-10. Salmonella TA98 Dose-Response Curves, Ontario Tire Burn
Sample 37
Figure 2-11. Salmonella TA98 Mutagram, Ontario Tire Burn Sample 39
LIST OF TABLES
Table 1-1. Quantitation and Emission Summary of Compounds Identified in
VOST Samples 9
Table 1-2. Quantitation and Emission Summary of Compounds Identified in
XAD-2 Extracts 12
Table 1-3. Organic Emission Summary 13
Table 1-4. PAH Quantitation and Emission Summary 13
Table 1-5. Particulate Collection Summary 14
Table 1-6. Airborne Particulate Metals Analysis Summary 15
Table 2-1. Mutagenic Potencies and Mutagenic Emission Factors of DCM-
Extractable Organics in TA98 23
Table 2-2. Chemicals Identified in HPLC Fractions of Particulate Organics
from Composite Tire Burn Sample 34
VI
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1. SUMMARY OF PREVIOUS WORK
1.1 INTRODUCTION
Approximately 240 million vehicle tires are discarded annually.1 Viable methods for
reclamation exist. Some of the attractive options for use of scrap tires include burning, either
alone or with another fuel, such as coal, in a variety of energy-intensive processes, such as
cement kilns and utility boilers.2'3'4 Another potentially attractive option is the use of ground
tire material as a supplement to asphalt paving materials. Congress has passed a law, the
Intermodal Surface Transportation Efficiency Act of 1991,5 which mandates that up to 20
percent of all federally funded roads in the United States include as much as 20 Ib (9 kg) of
rubber derived from scrap tires per ton (907 kg) of asphalt by 1997. In spite of these efforts, less
than 25 percent of the total amount of discarded tires are re-used or re-processed, and-the
remaining 175 million scrap tires are discarded in landfills, above-ground stockpiles, or illegal
dumps. In addition, these reclamation efforts do little to affect the estimated 2 billion tires
already present in stockpiles.
Many landfills are refusing to accept tires because they present not only disposal but also
health-related problems. After burial, tires often float to the surface and become partially filled
with water. Cutting the tire in half or in pieces can reduce this tendency. However, it is very
costly to cut or shred tires for landfilling purposes, and in any event, many sites lack the
necessary equipment. Steel-belted radials, which comprise the majority of the nation's
discarded tires, are particularly difficult to cut and/or shred. Often, they are simply stockpiled
or illegally dumped. These stockpiles and dumps can become a breeding ground for many
insects, especially mosquitoes, where water collects in the tires and creates an ideal breeding
habitat. The introduction and spread of several mosquito species has been directly attributed to
the presence of refuse tires.6
The growing incidence of tire fires creates another potential health hazard. More tire
stockpiles and illegal dumps are coming into existence, and with them the occurrence of tire
fires. These fires, often started by arson, generate a huge amount of heat, making them
extremely difficult to extinguish. Some of these tire fires have continued for months. For
example, the Rhinehart tire fire in Winchester, Virginia, burned for nearly 9 months,7 exuding
large quantities of potentially harmful compounds.
The EPA's Control Technology Center (CTC) received numerous requests from state and
local agencies nationwide for information pertaining to tire fires and their effects. Because very
little information was available, the steering committee felt a study investigating this potential
problem was warranted. Through the guidance of the Combustion Research Branch (CRB) of
EPA's Air and Energy Engineering Research Laboratory (AEERL), Acurex conducted a study in
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19898 which identified and quantified organic and inorganic emission products produced
during the simulated open combustion of scrap tires.
One of the findings of the 1989 study was that there are thousands of compounds present in
the emissions from a tire fire. Although many individual compounds were identified, and a
significant fraction of the organic mass was identifiable, only a small fraction of the total
number of chromatographic peaks were identifiable. The complexity of this mixture makes it
difficult to assess the threat to human health that is posed by a tire fire. Thus, the CTC funded a
small additional study to examine the health effects of the emissions from tire fires by using an
experimental technique known as bioassay-directed fractionation combined with additional gas
chromatography/mass spectroscopy (GC/MS) analyses.
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1.2 EXPERIMENTAL APPROACH
1.2.1 Project Description
The project consisted of a parametric study to collect organic and inorganic emissions from
the simulated open combustion of scrap tires. Small quantities (10-20 lb, 4.5-9.0 kg) of scrap-tire
material were burned under two different controlled conditions determined by the size of the
material. One size was about one-quarter to one-sixth of an entire tire and will be referred to as
the "CHUNK" condition. The other size consisted of 2 by 2-in. (5 by 5-cm) pieces of tire and will
be referred to as the "SHRED" condition. The conditions were evaluated in duplicate on
successive days. An existing burn hut used for similar projects was modified to accommodate
this task. A separate outbuilding housed the required organic and particulate sampling
equipment. CRB's Hazardous Air Pollutants Mobile Laboratory (HAPML) was used to monitor
fixed combustion gases, including oxygen (02), carbon dioxide (CO2), carbon monoxide (CO),
total hydrocarbons (THCs), and sulfur dioxide (SO2J. Organics were collected using the
Volatile Organic Sampling Train (VOST)9 and a semi-volatile collection system using XAD-2
and particulate filters. Particulate was also collected to assess airborne metals and to measure
the amount of particulate that was sized <10 ^m (PMio)- The organic constituents were
analyzed both qualitatively and quantitatively by GC/MS, gas chromatography/flame
ionization detector (GC/FID), high pressure liquid chromatography (HPLC), and gravimetric
(GRAY) methodologies.
1.2.2 Experimental Apparatus
1.2.2.1 Burn Hut
The burn hut was an 8 x 8 x 8-ft (2.4 x 2.4 x 2.4-m) outbuilding modified for small-scale
combustion experiments (see Figure 1-1). The building had been fitted with a cooled, dilution
3 3
air handling system capable of delivering nominally 1,200 ft /min (34.0 m /min). A
16 x 16 x 16-in. (0.4 x 0.4 x 0.4-m) stainless-steel burn pit insulated with fire brick was mounted
on a weigh scale to continuously monitor weight differential. A PMio ambient sampler was
located in the hut to collect particulate matter 10 |o.m in diameter or less. A deflector shield was
located 4 ft (1.2 m) over the pit to deflect flames, protect the ceiling, and enhance ambient
mixing. The gaseous sample duct opening was located directly over the deflector shield. This
duct transported a representative portion of gaseous sample to the sample shed immediately
adjacent to the burn hut (see Figure 1-2). The duct was insulated outside the hut to minimize
heat loss and condensation of organics.
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Sample Duct
V
Air Inlet
. Weighing Platform
Air Inlet1
Figure 1-1. Diagram of Burn Hut.
1.2.2.2 Sample Shed
The sample shed contained the majority of the sampling equipment: the VOST system, the
semi-volatile organic collection system, the airborne metals particulate collection system, the
continuous emission monitor (CEM), the particulate removal system, and the digital readout for
the weigh scale. All gaseous samples were extracted from a sampling manifold within the duct.
Figure 1-3 diagrams the individual sampling systems and illustrates how each obtained a
representative sample from the duct. Volatile and semi-volatile organics, metals, and
were collected and analyzed as described in the previous study.8
f
(
cz
Hazardous Air
Pollutants Mobile
Laboratory
CEMs - O2
-CO2
-CO
-THC
-S02
)
1 '
c
1 EPA 1
e
Heated
Cample
1
Sample Shed
Sampling Control Center
Particu
Volatile ail
Orgar
Airborne 1
ate Sampling
d Semi-Volatile
lie Sampling
Petals Sampling
0
nsulatcd
Samp
Duel
le
X
Burn Hut
/N
s,
Figure 1-2. Locations of Required Test Equipment.
-------
Note:
1/4" = 0.6 on
3/8" = 1.0 cm
Duct Cross Section
From Burn Hut
Heated Spun
'Glass Filter
142mm
Teflon
Coated
Filter
Water Cooled
Condenser
Vacuum
Pump
Figure 1-3. Diagram of Sampling Systems Used.
1.2.2.3 HAPML
The Hazardous Air Pollutant Mobile Laboratory is a modified recreational vehicle
containing all necessary equipment to perform emissions monitoring on stationary combustion
sources, including CEMs, online GCs, VOST, and Modified Method 5 (MM5) .sampling
capabilities. The laboratory contains a sample preparation area, and is fitted with a
microcomputer-based data acquisition system. A heated sample line was connected from the
particulate conditioning filter to the sample manifold in the HAPML. A portion of the heated
sample was routed to the SO2 and THC analyzers. The remaining portion of the sample stream
was further conditioned (moisture removal by a refrigeration condenser and silica gel) before
being routed to the C>2, CO2, and CO analyzers.
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1.3 DATA, RESULTS AND DISCUSSION
1.3.1 Burn Rate Results
As stated earlier, the size of tire material was varied to alter the combustion conditions and
to gain insight into the mechanisms governing burn rate. Rates were calculated by dividing the
amount of tire material burned by the length of the burn and then normalizing to a mass per
hour basis. The data show that the CHUNK condition produced a higher burn rate than the
SHRED condition. Almost double the amount of CHUNK material was combusted during
similar periods. :
Figure 1-4 is a plot of the burn rate vs. the elapsed time for all tests. All plots show a high
initial burn rate, but as time elapsed, it diminished. In both of the SHRED runs, after more than
midway through the test period, the burn pit had to be agitated to sustain combustion. This
agitation would account for the visible increase in burn rates occurring at that point.
Under both conditions, an initial high burn rate was observed to gradually level off until a
steady rate was achieved. Examination of the tire material suggested a possible explanation.
Along the tread portion, of the tires, a much thicker layer of rubber was found in relation to the
sidewall. In addition, the rubber of the sidewall portion seemed impregnated into the belt
material, yet the rubber in the tread surface contained no belt material. It may be that the tread
material is consumed first while the belt containing rubber may be more difficult to burn and
more uniform in its combustion.
12.
CHUNK Day 1
CHUNK Day 2
SHRED Day 1
SHRED Day 2
0
0
50
100
Elapsed time (min)
200
250
Figure 1-4. Burn Rate Vs. Elapsed Time.
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1.3.2 CEMData
Combustion gas products were monitored continuously throughout the test period. Figure
1-5 illustrates the data from the SC>2, CO, and THC analyzers for the four tests. The C>2 and CC>2
CEM data did not deviate significantly from ambient concentrations, so are not included in
these plots. Comparing these plots with the respective plots pertaining to burn rate shows a
relationship between high emissions of CO, SO2, and THC at high burn rates.
OH
CX
•***
§
•J3
(Q
o
U
500
400
300
200.
100
500.
400.
300.
200-
100-
500
400
300
200.
100.
500
400
300
200
0
CO
SO2
THC
CHUNK Day 1
CHUNK Day 2
SHRED Day 1
Agitation Point
100 150
Time (min)
200
250
Figure 1-5. CEM Concentrations Vs. Elapsed Time.
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1.3.3 Volatile Organic Emission Data
Identification of unknown organics using the MS proved to be highly successful. Table 1-1
lists the more than 50 compounds identified, their average gaseous concentrations, and
estimated emissions at the CHUNK and SHRED conditions. These values are estimates and are
calculated using the MS response to toluene from the VOST samples collected during testing.
The majority are aliphatically, olefinically, or acetylenically substituted aromatics. The
predominant formation of aromatic hydrocarbons is likely due to the high thermodynamic
stability of aromatic structures. A representative of each compound class is found in mono-
through poly-substituted aromatic hydrocarbons. Cyclic alkanes, alkenes, and dienes were also
present. It is not surprising to identify butadiene in the samples because it is a major
constituent of the tire fabrication process. A halogenated compound, trichlorofluoromethane,
was also identified in several of the collected samples. This chlorofluorocarbon (CFC), also
known as CFC-11, was probably emitted by the air conditioners used to dilute the air in the
burn hut. Several sulfonated compounds were identified in the samples. Thiophene and
substituted thiophenes were isolated. Nitrogenated hydrocarbons were found. Isocyano
benzene and benzodiazine were isolated in multiple samples.
The data presented in Table 1-1 represent an averaging of the three sets of VOST samples
taken at each run condition, each taken at different periods during the burn. The complete
listing of the data is presented in the previous report,8 and therefore is not reproduced here.
The data did not reveal consistent trends in either the types or amounts of emissions under
varied burn rates. Benzene is emitted in large quantities under both conditions. Average
gaseous concentrations increase with increased burn rate, but this is true with the majority of
the compounds presented. It is interesting to note, however, that as the burn rate decreased, the
amount of specific compounds emitted tended to increase with respect to the amount of tire
material combusted. It may be that during the latter portion of the burn period, the remaining
rubber in the tire material was bound with the cord material and became difficult to burn. In
this lower temperature regime, the rubber continued to be pyrolyzed, but less was combusted
while the volatiles reacted to form the types of compounds identified.
The estimated emissions presented are based on several variables. They were obtained by
assuming that the dilution air added to the burn hut was at a constant volume and that the
amount of air added equaled the amount exiting the hut. It was also assumed that the gas
mixture collected in the sample duct was well mixed and representative of the gas mixture
found throughout the burn hut. The average gaseous concentration or average concentration of
the sample over a given period was determined by dividing the total collected amount
(obtained by GC/MS analysis) by the volume of sample collected. This value was then
multiplied by the amount of air added to the burn hut in 1 h. This value is the amount of a
specific compound emitted on an hourly basis, and it was then divided by the burn rate
8
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Table 1-1. Quantitation and Emission Summary of Compounds Identified in VOST Samples.a'b'c
Compound Identified
CHUNK
Concentration (mg/nv*) Estimated Emissions
SHRED
Concentration (mg/m3) Estimated Emissions
benzaldehyde
benzene
benzodiazine
benzofuran
benzothiophene
butadiene
cyclopentadieno
dihydroindene
dimethyl benzene
dimethyl hexadiene
dimethyl,methylpropyl benzene
dimethyldihydro indene
ethenyl benzene
ethenyl cyclohexene
ethenyl,dimethyl benzene
ethenyl,methyl benzene
ethenyldimethyl cyclohexene
ethenylmethyl benzene
ethyl benzene
ethyl,methyl ben/ene
ethyl,methyl benzene
ethynyl benzene
ethynyl,methyl benzene
heptadiene
isocyano benzene
limonene
methyl benzene
methyl cyclohexene
methyl hexadiene
methyl indene
methyl indene
0.260
1.910
0.017
0.049
0.014
0.152
0.081
0.013
0.413
0.008
0.000
0.007
0.678
0.006
0.014
0.016
0.000
0.129
0.182
0.015
0.105
0.322
0.562
0.009
0.341
0.011
0.976
0.005
0.021
0.078
0.060
(mg/kg tire)
299.2
2156.3
13.7
25.1
26.3
308.4
48.6
40.6
779.7
28.3
0.0
22.0
941.8
26.2
7.2
14.1
0.0
221.6
460.8
46.7
287.8
190.0
530.6
25.4
347.4
27.5
1606.4
21.1
71.3
191.5
124.9
0.215
1.401
0.014
0.000
0.011
0.096
0.000
0.021
0.629
0.049
0.008
0.008
0.395
0.060
0.014
0.014
0.193
0.028
0.164
0.023
0.239
0.110
0.226
0.028
0.191
0.513
0.714
0.023.
0.068
0.028
0.059
(mg/ kg tire)
329.6
2204.8
17.4
0.0
14.7
160.8
0.0
42.8
1078.2
90.9
14.9
17.7
611.4
107.6
23.7
19.5
350.4
40.9
295.1
44.8
431.0
"131.5
258.7
51.4
289.7
892.5
1129.1
40.1
127.2
43.0
97.1
(continued)
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Table 1-1. Quantitation and Emission Summary of Compounds Identified in VOST Samples
Compound Identified
Concentration (mg/m3) Estimated Emissions
SHRI
Concentration (mg/m3)
Estimated Emissions
methyl naphthalene
methyl naphthalene
methyl thiophene
methyl,ethenyl benzene
methyl,methylethenyl benzene
methyl,methylethyl benzene
methyl,methylethyl benzene
methyl,methylethyl c.h.
methyl,propyl benzenze
methylene indene
methylethyl benzene
naphthalene
pentadiene
phenol
propyl benzene
tetramethyl benzene
tetramethyl benzene
thiophene
trichloro-flouromethane
trimethyl benzene
Totals
a Concentrations determined
0.136
0.151
0.006
0.027
0.046
0.019
0.022
0.000
0.000
0.038
0.045
1.285
0.077
0.002
0.026
0.000
0.000
0.023
0.158
0.022
128.1
183.4
5.5
55.7
98.0
57.7
53.7
0.0
0.0
48.5
134.9
1130.0
163.9
0.5
72.4
0.0
0.0
54.6
57.6
46.9
8.534 11182.0
using system response to toluene.
b These data are averaged over six sets of VOST tubes per day taken
c DimliratpH rnmnmiml nam
PS inrliratp mnlHnlp isomers of thp sam
over 2 days.
IP romnound.
0.066
0.069
0.007
0.045
0.373
0.094
0.071
0.086
0.020
0.022
0.092
0.607
0.680
0.016
0.046
0.046
0.084
0.021
0.000
0.042
8.029
90.3
106.3
12.6
76.6
683.5
163.3
120.2
170.0
41.6
34.4
169.4
823.6
1162.6
14.3
84.2
97.7
158.0
27.9
0.0
74.9
13067.8
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determined for that period. The burn rate, as outlined earlier, was determined by dividing the
amount of tire material combusted in a specific period by that amount of time (in minutes) and
normalizing it to an hourly basis. The resultant value is an emission estimate of the amount of
compound emitted at a specific burn rate. Finally, the total for the day's runs was derived by
averaging the results for the three VOST tubes based on total sample volume. The two CHUNK
runs were then averaged together, as were the two SHRED runs.
1.3.4 Semi-Volatile Organic Emission Data
As with the volatile organic analyses, the MS analysis of the XAD-2 extracts identified the
same types of compounds. Table 1-2 lists the 37 compounds identified and indicates that
substituted mono- and polyaromatics were again the predominant PIGs. The data in Table 1-2
are an average of three samples taken over the entire course of the day's run. The quantities
found in each individual sample roughly parallel the burning rate; i.e., the early samples had a
higher loading and the later samples had a lower loading of semi-volatile organics. Many of the
compounds collected and identified by the VOST technique were also found in the XAD-2
extracts. Table 1-2 shows that similar ambient-loading and emission-rate values were realized
from the XAD-2 extracts. The emission rate for many compounds increased with decreasing
burn rate, but not for all. The emission of naphthylene, for example, was much greater at higher
burn rates, as evidenced during the CHUNK condition. In addition, the average gaseous
concentration is also greater in this situation. This finding contrasts with the trends observed in
the VOST samples.
The particulate filters located upstream of the XAD-2 canisters contained considerable
quantities of organics. The majority of compounds found in the particulate have boiling points
exceeding 300 °C. Table 1-3 summarizes semi-volatile organic emission data from all four test
conditions. The total organics from respective boiling-point-based analyses are presented for
each component of the sampling media. The emission rate data presented show that from 12 to
50 g of semi-volatile organics can be emitted for every kilogram of tire burned. It appears that,
as burn rate decreased, the amount of organics emitted, particularly in the total
chromatographable organic (TCO) range, increased. There did not seem to be any significant
variation in GRAV range organic emissions when related to burn rate.
11
-------
Table 1-2. Quantitation and Emission Summary of Compounds Identified in XAD-2 Extracts.
CHUNK
Compound Identified
methyl benzene
ethyl benzene
dimethyl benzene
ethynyl benzene
styrene
methylethyl benzene
propyl benzene
benzaldehyde
trimethyl benzene
phenol
cyanobenzene
trimethyl benzene
methyl,methylethyl benzene
limonene
indene
tetramethyl benzene
ethyl,dimethyl benzene
methyl benzaldehyde
ethyl,dimethyl benzene
propenyl,methyl benzene
methyl indene
methyl indene
naphthalene
benzo[b]thiophene
benzisothiazole
hexahydro azepinone
2-methyl naphthalene
1 -methyl naphthalene
biphenyl
dimethyl naphthalene
acenaphthalene
1,1' biphenyl, methyl
isocyano naphthalene
propenyl naphthalene
trimethyl naphthalene
1H fluorene
phenanthrene
Totals
Average
Concentration
1.105
0.181
0.254
0.254
0.605
0.040
0.000
0.218
0.000
0.330
0.199
0.191
0.107
0.047
0.462
0.000
0.000
0.000
0.000
0.000
0.093
0.000
1.578
0.050
0.000
0.062
0.314
0.292
0.186
0.034
0.580
0.013
0.011
0.027
0.000
0.187
0.173
7.593
Estimated
Emissions
(mg/kg tire)
1212.2
205.2
305.0
275.8
659.9
48.3
0.0
244.1
0.0
365.9
223.7
209.4
127.9
56.1
503.4
0.0
0.0
0.0
0.0
0.0
111.8
0.0
1697.9
44.2
0.0
75.1
350.7
330.7
209.5
41.1
633.8
11.1
9.4
23.5
0.0
210.3
183.7
8369.7
Average
Concentration
(ms/m3)
0.816
0.197
0.544
0.112
0.380
0.133
0.127
0.180
0.249
0.412
0.300
0.197
0.821
1.361
0.201
0.049
0.073
0.047
0.085
0.282
0.171
0.063
0.671
0.000
0.094
0.445
0.255
0.133
0.193
0.096
0.318
0.000
0.000
0.000
0.185
0.183
0.119
9.492
Estimated
Emissions
(mg/kg tire)
1390.1
337.6
935.1
187.4
645.5
229.1
219.6
333.9
• 413.3
700.2
516.8
338.1
1426.1
2345.5
339.2
91.9
114.7
86.6
157.7
523.6
302.4
98.3
1130.7
0.0
173.9
748.5
429.2
227.6
330.1
178.1
531.1
0.0
0.0
0.0
315.8
308.4
187.0
16293.1
Concentrations determined using system response to TCO calibration mix.
12
-------
Table 1-3. Organic Emission Summary.
CHUNK
SHRED
Average Gaseous
Concentrations (mg/m3)
Estimated Emissions
(mg/kg tire)
TCO
GRAY
Total
TCO
GRAY
Total
3514.6
4048.0
7562.6
9792.0
11223.5
21015.5
8473.0
4151.9
12624.9
31686.0
14888.0
46574.0
A polycyclic aromatic hydrocarbon (PAH) analysis by HPLC was performed on the liquid
extractions of the XAD-2 and filter components. The results of the analyses are presented in
Table 1-4. The 16 PAHs include several compounds known to be carcinogenic. In particular,
the presence of benzo(a)pyrene (BAP) is of major importance. It is a highly scrutinized
compound when evaluating combustion processes. Although no trend in concentration related
to burn rate exists, the magnitude of the emissions warrants concern.
Table 1-4. PAH Quantitation and Emission Summary.
CHUNK SHRED
Compound
naphthylene
acenaphthylene
acenaphthene
fluorene
phenanthrene
anthracene
fluoranthene
pyrene
benz(a)anthracene
chrysene
benzo(b) fluoranthene
benzo(k )fluoranthene
benzo(a)pyrene
dibenz (a,h)anthracene
benzo(g,h,i)perylene
indeno(l ,2,3-cd)pyrene
Totals
Average
Concentration
(mg/m3)
0.786
0.802
0.282
0.243
0.225
0.053
0.324
0.030
0.076
0.068
0.064
0.069
0.080
0.001
0.060
0.049
3.212
Estimated
Emissions
(mg/kg tire)
815.9
861.3
290.3
260.5
237.5
56.3
338.7
33.8
82.2
70.8
69.4
74.3
84.8
1.1
66.0
51.6
3394.5
Average
Concentration
(mg/m3)
0.289
0.334
1.404
0.112
0.149
0.029
0.273
0.090
0.062
0.056
0.053
0.059
0.068
0.000
0.095
0.051
3.124
Estimated
Emissions
(mg/kg tire)
486.0
561.8
2445.7
186.8
252.5
49.6
458.0
151.7
102.4
91.6
88.4
99.4
113.9
0.0
159.4
85.5
5332.7
The PAH analysis accounted for only roughly 10 percent of the GRAY range organics. It
was not possible to identify the remaining portion because of equipment limitations. The
GC/MS system used was not set up for high temperature applications, so this area remains
unexplored. It may be possible that carbon black, a major constituent of tire material, may exist
as sub 0.45 mm particles that passed through the filter during cleanup of the particulate
extraction. It may also be possible that some of the discrepancy between the PAH and GRAY
results may be due to suspected low sample recoveries for the PAH analysis.
13
-------
1.3.5 Particulate Emission Data
The particulate was collected using three separate systems. Particulate was captured with
the semi-volatile organic system, with the airborne metals particulate collection system, and
with a medium volume PMio sampler located in the burn hut. Table 1-5 summarizes the
particulate loading values of these three systems for the four test conditions. For total average
gaseous concentration there seems to be good agreement between the organic particulate and
the metals particulate systems during each test condition. Moreover, average gaseous
concentration increased with increased burn rate. As the burn rate decreased, the percent of
organics extracted increased. This finding is important because, although under reduced
average gaseous concentration, the amount of organic material that the particulate contains is
greater. Comparing burn rate to estimated particulate emissions shows that the emission rate of
particulate decreased with lower burn rates, although nearly 100 g of particulate was emitted
for every kilogram of tire combusted.
Table 1-5. Particulate Collection Summary.
Sample
Organic
Particulate
Filter
Metal
Particulate
Filter
PMio Filter3
Average Cone.
(mg/m3)
93
111.55
444.14
CHUNK
Estimated
Emissions
(me/ kg tire)
97167.95
105075.1
113545.4
Extractable
Organic (%)
10.6
Average Cone.
(mg/m3)
43.75
37.9
92.85
SHRED
Estimated
Emissions
(mfi/ks tire)
73468.15
64535.05
149023.8
Extractable
Organic (%)
19.65
a The PMio sampling filter became heavily loaded during the initial part of each run. The
results are biased high, due to higher burning rates that occurred during this portion of the
run.
The PMio sampler was used to assess the amount of particulate found in the 10 |o.m or less
range. Surface area is an important criterion when determining particulate emission standards
and assessment. Particulate of this size, once airborne, tends to persist in the atmosphere for
long periods and to become an inhalation problem. Owing to the nature of the sampler and the
application to this study, several problems were encountered during data collection. The
ambient sampler was designed to operate constantly at 4 cfm (0.113 m3/min). This relatively
high flow rate was difficult to maintain because of the rapid loading of the particulate filter. As
the loading increased, the flow rate through the system decreased until the required flow rate
could no longer be obtained. The 4 cfm flow rate was required to maintain the specific cut-off
point for particulate sizing. As the flow rate decreased, the size of particulate reaching the filter
increased; therefore, the data presented may not be valid because the required flow rate was not
maintained, although sampling still continued despite inadequate flow.
14
-------
1.3.6 Airborne Metals Data
A separate participate collection system was operated to verify and quantify the presence of
metals collected from ambient emissions. Seventeen target metals reportedly found in tires
were isolated.10 The list was compiled from information on combusted-tire ash residues.
Table 1-6 shows the results of the metal analyses. The results from the method blank are also
included to demonstrate the marginal differences between the blank and collected samples.
Many of the analyses are at or near instrument detection levels. The only significant differences
between the blank and sample were found with lead and zinc. The lead results are extremely
close to the instrument detection level of the element. The major difference was found in the
zinc analyses. Many of the estimates are based on the detection levels themselves and .are
presented as "less than" quantities. The zinc data suggest that both average gaseous
concentration and estimated emissions increased with increased burn rates.
Table 1-6. Airborne Particulate Metals Analysis Summary.3
Metal
aluminum
arsenic
barium
calcium
chromium
copper
iron
magnesium
sodium
nickel
lead
antimony
selenium
silicon
titanium
vanadium
zinc
Blank
Filter
Total
(mg)
0.020
<0.0005
<0.01
0.030
0.010
<0.002
0.060
0.004
0.020
0.010
<0.0005
<0.02
<0.0005
0.130
<0.05
<0.05
0.010
Filters
CHUNK SHRED
Filter
Total (mg)
0.019
<0.0005
<0.01
0.050
0.010
<0.002
0.060
0.007
0.053
0.011
0.002
<0.02
<0.0005
0.229
<0.05
<0.05
0.206
Filter
Total
(mg)
0.020
<0.0005
<0.01
0.040
0.014
<0.002
0.065
0.007
0.050
0.009
0.001
<0.02
<0.0005
0.235
<0.05
<0.05
0.215
Cone.
(mg/m3)
0.0079
0.0012
0.0084
0.0004
0.0410
0.0409
Emissions
SHRED
Estimated Cone.
Emissions (mg/m3)
(mg/kg tire)
8.54
1.26
9.51
0.47
34.96
31.17
0.0028
0.0005
0.0035
0.0001
0.0162
0.0146
Estimated
Emissions
(mg/kg tire)
4.80
0.75
5.80
0.10
27.55
24.35
Sample filters made of quartz: possible silicon contamination
15
-------
1.4 SUMMARY AND CONCLUSIONS
The primary goal of this project was to characterize potentially harmful emissions from the
simulated open burning of scrap tires. The simulation was necessarily crude, because it would
be extremely difficult to match the burning of the equivalent of two tires with a 6 million tire,
full-scale, stockpile fire. Nevertheless, the study allowed the investigators to identify and
measure gaseous emissions and directly relate this information to a mass burn rate. This task
was accomplished by accurately measuring dilution volumes, sample volumes, and weights of
tire material combusted.
The dilution air added to the burn hut was used not only to control known volumes
introduced, but also to simulate ambient conditions. It is probable that the same types of
compounds identified during this study are emitted during an actual fire, but whether the
average gaseous concentrations and estimated emissions are comparable is uncertain. A
comparison with limited data collected at the Winchester, Virginia, fire by NIOSH,11 indicates
that reasonable agreement exists within several measurement areas. Many of the same
compounds were identified in actual plume samples. Particularly good agreement exists in
PAH plume measurements. NIOSH reported that ambient concentrations of total PAHs are
generally within the same order of magnitude as average gaseous concentrations obtained
during testing. Measurements of CO and metals also indicate similar agreement. The lead and
zinc measurements show similar values both in gaseous and relative concentrations between
the two metals. It may be reasonable to assume that the estimates obtained during this study
are within an order of magnitude of emissions realized from actual stockpile fires.
The results from the airborne metals portion of the study were inconclusive. Maximum
values were presented, often based on detection levels. Emissions of lead and zinc may. reach
significant quantities. Chemical analysis of ash residues reveals that zinc comprises nearly
50 percent of the total residue.10 Evidently, the other metals known to be contained in tires
remain in the ash residue. Although no attempt was made to analyze ash residue, significant
quantities of metals present in the ash could potentially be leached out into groundwater
systems, posing another major problem.
The values obtained by the on-line analyzers for normal combustion gases showed that, as
burn rate increased, the amount of CO, SO2, and unburned hydrocarbons also increased. High
burn rate conditions were not fully evaluated, so greater quantities of these gases, particularly
SO2, may be emitted during a stockpile fire. Tires contain a significant amount of sulfur, so
high emissions of SO2, while likely only a minor contributor to the acid rain problem, could
have significant local consequences.
This study was designed to identify the potential chemical hazards from tire fires on a
small-scale, simulation basis. The study reveals the potential for the emission of great amounts
16
-------
of organic compounds, primarily aroma tics, some of which may be extremely harmful.
Although the estimates of average gaseous concentrations and estimated emissions are crude,
the trends presented in regard to burn rate may be helpful in directing further research and
control efforts. The fact that the SHRED condition resulted in a lower burn rate indicates that
the gaps between the tire material provide the major avenue of oxygen transport. Oxygen
transport appears to be a major if not the controlling mechanism for sustaining the combustion
process. This fact could have advantageous implications for those attempting to combat tire
fires. It may be possible to fill the gaps between tires with a foam inhibitor, potentially
suffocating the fire from within.
The extreme complexity of the organic emissions confounded attempts to quantify all
compounds present. In fact, only around 10 percent of the chromatographic peaks were
identified, although most of the organic mass was identified. This suggested that a different
approach to emissions measurements, one that applies to complex mixtures, might be useful.
The CTC provided additional funding to examine the complex mixtures resulting from
simulated open combustion of scrap tires with the bioassay directed fractionation technique.
The relative potency of the emissions could then be compared to other well-characterized
combustion sources.
17
-------
OPEN TIRE BURNING
2.1 INTRODUCTION
Products of incomplete combustion (PICs) are present in all combustion emissions, and, in
general, they have been found to be carcinogenic in humans and rodents and mutagenic in
bacteria and mammalian cells.12 Mutagenicity bioassays have been shown to be one of the most
useful methods by which to evaluate the health effects of airborne mutagens and potential
carcinogens present in the PICs from a variety of combustion emissions.13 Mutagenicity assays
of chemical fractions of complex mixtures such as PICs have facilitated the identification of the
chemical classes and species responsible for some of the mutagenic activity of PICs. This
coupling of bioassays to chemical fractionation is called bioassay-directed chemical analysis.14
Bioassay-directed chemical analysis has been used successfully to identify mutagens from a
variety of combustion emissions, including diesel exhaust, kerosene heaters, PIC-impacte.d
urban air, woodsmoke, and incinerators.15'16'17'18'19'20 Recently, we have used diagnostic
strains of bacteria that permit the presumptive identification of mono- vs. dinitroaromatic
compounds in incinerator effluents and to investigate the effect of various combustion
technologies on the mutagenicity of the effluents.21'22
Considerable research has been performed on the mutagenic and carcinogenic properties of
chemicals associated with the rubber industry.23'24 These studies have shown that a wide
variety of mutagens and carcinogens are present in the rubber industry and that carcinogenic
and other types of health effects have been associated with rubber workers. Although mutagens
have been extracted from rubber25 and identified in the atmosphere in the rubber industry,26 no
studies have been performed on the potential health effects of the effluent produced by the open
burning of tires. Thus, the purpose of the present study was to evaluate the mutagenicity of the
dichloromethane (DCM)- extractable organics from the effluent produced by the open burning
of tires.
18
-------
2.2 EXPERIMENTAL PROCEDURES
DCM extracts from XADs and filters containing the effluent from the tire burns (acquired
from the semi-volatile organics sampling system) were solvent exchanged into dimethyl
sulfoxide (DMSO) and evaluated for mutagenic activity in the Salmonella (Ames) mutagenicity
plate-incorporation assay using strain TA98.27 The assay consists of combining the bacteria
along with the organics in the appropriate agar medium in a petri dish, incubating the dish for 2
days at 37°C, and then counting the bacterial colonies (a cluster of cells) on the plate. Each
colony represents a mutational event (a mutation), and each colony is called a mutant or, more
specifically, a revertant. The results of the Salmonella mutagenicity assay are expressed as the
number of revertants/plate produced per microgram of organics/plate (or rev/|j.g).
Many environmental mutagens and carcinogens are not mutagenic or carcinogenic per se
but are converted by enzymes in the body to chemical species that are mutagenic and
potentially carcinogenic. Because bacteria lack many of these enzymes, the enzymes (obtained
from rat liver) are added to the petri dish along with the bacteria in order to provide this aspect
of mammalian metabolism. The enzymes are added along with the bacteria and the organics to
the petri dish in the form of a rat liver homogenate called S9 (because it is the Supernatant
resulting from a 9000 x g centrifugation of homogenized rat liver).
19
-------
2.3 DATA, RESULTS AND DISCUSSION
2.3.1 Mutagenic Potency of Organics
Figures 2-1 and 2-2 show the mutagenicity dose-response curves for the XAD and filter
DCM extracts from day 1 and day 2 CHUNK or SHRED effluents. The slopes of these curves
(based on linear regressions) produce a value called the mutagenic potency; i.e., the number of
revertants produced by 1 M-g of DCM-extractable organics. Because the flow rate through the
XAD and filters was known, the micrograms of organics could also be expressed in terms of
cubic meters, which provided another way of expressing the mutagenic potency; i.e.,
revertants/cubic meter.
Table 2-1 shows the mutagenic potencies of the organics (rev/p,g or rev/m^) based on the
slopes of the mutagenicity dose-response curves in Figures 2-1 and 2-2. The mutagenic potency
(rev/|ig) of the semi-volatile organics (XAD) was similar for CHUNK and SHRED conditions;
i.e., ~1 to 2 rev/pig. The exception was the day 2 SHRED XAD sample, which was considerably
more potent, perhaps due to the agitation of the burn pit during this burn in order to sustain
combustion. The mutagenic potency (rev/ng) of the particulate organics (filter) was generally
greater than that of the semi-volatile organics, ranging from ~2 to 12 rev/ng. In the presence of
S9, the particulate organics from the CHUNK tires exhibited greater mutagenic potency than
those from the SHRED experiments; whereas, in the absence of S9, the reverse was observed
(Table 2-1).
The mutagenic potencies of these organics are similar to those obtained from a variety of
combustion emissions, although the mutagenic potencies of the particulate organics from
CHUNK tires in the presence of S9 (-10-12 rev/ng) are in the upper end of the range of values
typically found for combustion emissions. The greater mutagenic potencies in the presence of
S9 of the particulate organics from CHUNK tires may have been due to the greater initial burn
rate that was achieved with CHUNK tires. A greater burn rate might have produced more
PAHs, which would be typical of the class of compounds that require S9 in order to be
mutagenic.
20
-------
100
80
EPA Tire Burn
TA98, XAD
Chunk
D.
1 °c
CO
•e
SJsoo
-------
400
300
200
EPA Tire Burn
TA98, Filter
Chunk
c
CO
•d
gsoo
0
^250
EPA Tire Burn Dtty1^S9)
TA98, Filter Day2<+s9>
Shred
10 15
Dose (jjg/plate)
20
25
Figure 2-2. Mutagenic Potencies of Particulate Filter Extracts.
22
-------
Table 2-1. Mutagenic Potencies and Mutagenic Emission Factors of DCM-Extractable Organics in TA98.
Filt.
extractable
Burn organic
rate matter
Day Condition (kg/h) (%) S9 ng
1 CHUNK 9.4 4.5 + 2.2
1.9
SHRED 1.1 22.6 + 0.7
1.0
2 CHUNK 3.5 6.8 + 2.1
1.4
SHRED 1.3 16.7 + 4.3
8.9
XAD
m3
1536
1326
623
890
1573
1049
4726
9781
(revertants per)
kg of
fuel
xlO5
14.88
12.85
0.17
0.25
18.76
12.51
59.26
122.65
MJof
heat
42690
36866
487
717
53822
35891
170016
351822
^
12.0
2.3
4.3
8.9
10.4
2.3
7.0
7.0
Filter (revertants per)
m3
403608
77358
29335
60716
192379
42545
61397
61397
kg of
fuel
xlO5
873.61
167.44
484.23
100.25
1036.52
229.23
769.25
769.25
MJof
heat
2506387
480385
1389255
2875455
2973775
657660
2206978
2206978
-------
Likewise, the decreased mutagenic potency in the absence of S9 of the particulate organics
from CHUNK tires might also have been due to the greater burn rate that was achieved with
CHUNK tires. A greater burn rate might have resulted in the presence of fewer substituted
PAHs in the particulate organics from the CHUNK tires. Thus, substituted PAHs would be
more prevalent in the particulate organics from the SHRED experiments, and substituted PAHs
are frequently mutagenic in the absence of S9; whereas PAHs show an absolute requirement for
S9 in order to be mutagenic.
Consequently, the profile of mutagenic potencies of the organics in the presence and
absence of S9 are consistent with the burn rates that resulted from CHUNK vs. SHRED
conditions. CHUNK tires produce more potent organics as assayed in the presence of S9, but
SHRED tires produce more potent organics as assayed in the absence of S9. This difference is a
reflection of the different classes of chemical mutagens that are produced under the two
combustion conditions.
2.3.2 Mutagenic Emission Factors
Another way in which the mutagenic activity of the tire burn effluents can be expressed is in
terms of the amount of mutagenic activity per unit weight of tires combusted
(revertants/kilogram of fuel) or per unit heating value of tires combusted
(revertants/megajoule of heat). Such expressions of mutagenic activity are called mutagenic
emission factors, and they are a function of the mutagenic potency of the organics (rev/ng), the
burn rate (kg/h), the flow rate (m^), and the percentage of DCM-extractable organics collected
on the XAD and filters. Table 2-1 shows the mutagenic emission factors expressed in two
different ways for both the XAD and filter DCM-extractable organics from the effluents
produced by CHUNK and SHRED conditions.
With regard to the semi-volatile organics (XAD), the mutagenic emission factors for the
CHUNK tires in the presence of S9 were greater than those for SHRED conditions for the day 1
burns (Table 2-1). However, the reverse was true for the day 2 burns. This discrepancy was
likely due to the different burn rates that occurred on the different days and, perhaps, to other
factors. Interestingly, the mutagenic emission factors for the semi-volatiles were similar with or
without S9, with the exception of the day 2 SHRED experiment (Table 2-1). Thus, in general, it
appears that a similar amount of the mutagenic activity of the semi-volatile organics is due to
S9-dependent mutagens, such as PAHs, as well as to S9-independent mutagens, such as
substituted PAHs.
With regard to the particulate organics (filter), the mutagenic emission factors for the
CHUNK runs were greater than those for SHRED runs in the presence of S9; the reverse was
true in the absence of S9. Thus, the bioassay results suggest that, perhaps, the particulate
organics from the burning of CHUNK tires contained more PAH-type (S9-requiring) mutagens
24
-------
than those from SHRED tires and that the particulate organics from SHRED tires contained
more S9-independent mutagens (such as substituted PAHs) than those from CHUNK tires. This
difference in the chemical composition of the particulate organics is a direct consequence of the
combustion conditions resulting from the burning of CHUNK vs. SHRED tires.
It is clear from the data in Table 2-1 that (a) the DCM-extractable particulate organics exhibit
greater mutagenic potency (rev/ng) compared to the semi-volatile organics and (b) the vast
majority of the mutagenic activity (as measured by the calculation of mutagenic emission
factors) derives from the DCM-extractable particulate organics, as opposed to the semi-volatile
organics. Because of the relatively greater contribution of the particulate organics, compared to
the semi-volatile organics, to the mutagenic activity of the tire burn effluent, it would be
informative to compare the particulate mutagenicity emission factors to those of other
combustion emissions. Such a comparison would permit the mutagenic and potential
carcinogenic risks from the open burning of tires to be placed in perspective to those from other
combustion systems.
Most of the mutagenic emission factors that have been determined for other combustion
emissions have been for the DCM-extractable particulate organics evaluated in Salmonella
strain TA98 in the presence of S9. Because the mutagenic emission factors for the particulate
organics in the presence of S9 are similar for the CHUNK and SHRED conditions, we calculated
the arithmetic average of the four values (two from day 1 and two from day 2) to arrive at a
single mutagenic emission value in the presence of S9 for the open burning of tires. Figure 2-3
compares the mutagenic emission factor of the open burning of tires to those of other
combustion emissions as evaluated in strain TA98 in the presence of 59. The various
combustion emissions rank the same regardless of which way the mutagenic emission factors
are expressed. The mutagenic emission factor for open tire burning is the greatest of any other
combustion emission studied previously (Figure 2-3). For example, it is 3-4 orders of magnitude
greater than the mutagenic emission factors for the combustion of oil, coal, or wood in utility
boilers. The data in Figure 2-3 labeled "kiln" are from small-scale experiments examining
emissions from off-spec combustion of the listed compounds in a laboratory-scale rotary kiln
incinerator simulator. The data labeled "Dinoseb" are from pilot-scale studies examining the
effect of nitrogen oxide (NOX) reducing combustion modifications on the boiler emissions from
burning highly nitrated wastes. The data labeled "Open Ag. Plastic Burning' are from a
controlled experiment examining emissions from open burning of agricultural plastic. All other
data are from field samples.
The mutagenic emission factors for the residential combustion of wood and for the open
burning of agricultural plastic are closest to that of the open burning of tires (Figure 2-3). Both
of these combustion conditions represent a type of open burning similar to that of the tire burns
in the present study. All three situations have poor combustion characteristics, and this is
25
-------
N)
Natural Gas (kiln)
Cardboard & Sorbent (kiln)
Polyethylene (kiln)
Toluene (kiln)
Polyethylene/PVC (kiln)
Toluene/CC14 (kiln)
Utility Oil
Utility Coal
Utility Wood
Stage Dinoseb (boiler)
Stage & Reburn Dinoseb (boiler)
Residential Oil
Residential Wood
Municipal Waste Combustion
Open Ag. Plastic Burning
Open Tire Burning
10 10 10 10 10 10 10 10 10
Rev/kg of Fuel xlO5
Rev/MJ
Figure 2-3. Mutagenic Emission Factors of Combustion Emissions in Salmonella Strain TA98 (+S9)
-------
reflected in their high mutagenic emission factors. Thus, poor combustion conditions result in
elevated levels of PICs, which result in elevated mutagenic emission factors. It is clear from the
comparison in Figure 2-3 that the open burning of tires (as well as of wood or plastic) results in
exceptionally high mutagenic emission factors. Thus, open burning, regardless of the feed stock
or fuel, results in greater mutagenic emission factors than does controlled combustion provided
by various types of incinerators or boilers.
2.3.3 Bioassay-Directed Fractionation and Chemical Analysis
In order to identify some of the chemical classes and individual chemicals that might be
responsible for the observed mutagenic activity of the tire burn effluent, the DCM-extractable
particulate organics were subjected to bioassay-directed fractionation and chemical analysis. As
discussed previously, this method has been used successfully to identify mutagens from a
variety of combustion emissions (see Section 2.1).
The fractionation of a complex mixture by high pressure liquid chromatography (HPLC)
and the analysis of each fraction for mutagenicity by means of a microsuspension mutagenicity
assay produces a bioassay profile (mutagram) that identifies those HPLC fractions that contain
mutagenic activity.28,29 We have applied this method of analysis to indoor air particles30 as
well as to emissions from wood stoves,1^ municipal waste incinerators,20 and prototype
hazardous wastes combusted under suboptimal conditions in a laboratory-scale rotary kiln
incinerator.20'21 Bioassay-directed chemical analysis has also been used to identify mutagens in
coastal marine sediments.31
Fractionation by HPLC of the DCM-extractable particulate (filter) organics resulting from
the open burning of CHUNK or SHRED tires from the day 1 and day 2 burns was performed in
a manner similar to that described previously.20'21 Briefly, 500 |j.g of DCM-extractable organics
from each burn condition were injected into a Varian 5560LC containing an Econosphere silica
3-(im column (4.6 x 150 mm). The step-gradient started at 100 percent n-pentane, which was
held for 15 min, followed by a 25-min gradient to 100 percent DCM, which was held for 15 min,
followed by a 5-min gradient to 100 percent methanol, which was held for an additional 5 min.
All gradients were linear, all flows were 1 mL/min, and one fraction (1 mL) was collected per
minute, resulting in 60 fractions/sample. Each sample was fractionated twice so that one set of
fractions could be evaluated for mutagenicity in the presence of S9 and the other in the absence
ofS9.
Figures 2-4 and 2-5 show the chromatograms generated for the four samples based on
ultraviolet (UV) absorption at 254 nm. The four chromatograms are rather similar, showing
three main peaks of UV absorption. The first peak coincides with the elution of four of the
standards (naphthalene, benzo(a)pyrene, pyrene, and 1-nitropyrene); the third peak coincides
27
-------
PAH Elution
1,2 3 4
w
t
100 r
HPLC Chromatogram
Day 1
Chunk
0 5 10
(/) PAH Elution
O 1* 3 4
CL
8>
•^ 100 r
15 20 25 30 35 40 45 50 55 60
W
t
HPLC Chromatogram
Day 1
Shred
0 5 10 15 20 25 30 35 40 45 50 55 60
Fraction number
Figure 2-4. HPLC Chromatogram, Day 1 Results.
28
-------
PAH Elution
1.2 3 4
w
100 r n
HPLC Chromatogram
Day 2
Chunk
0 5 10 15 20 25 30 35 40 45
PAH Elution
50 55 60
o '
8- ttt
-------
with the elution of acridine. Mass recovery from the column was 91 and 78 percent,
respectively. The black anows labeled 1-5 mark the standard elution areas.
Figures 2-6 and 2-7 show the mutagrams generated for the four samples as determined in
strain TA98 in the presence and absence of S9. As with the chromatograms, the mutagrams of
the four samples are qualitatively similar. In general, the distribution of mutagenic activity as
fractionated by the present method is similar for the effluent produced by the open burning of
either CHUNK or SHRED tires. There are four general areas in which most of the mutagenic
activity elutes, and more of the fractionated mutagenic activity appears in the absence, rather
than in the presence, of S9.
The purpose of bioassay-directed fractionation is to allow the biology (i.e., the mutagram) to
guide the selection of fractions for detailed chemical analysis. Because of the (a) similarity of the
mutagrams from CHUNK and SHRED tires, and (b) limited resources available to perform
chemical analyses on all of the mutagenic fractions from all of the samples, the unfractionated
DCM extracts from the four samples were combined, and the composite sample was then
fractionated as described previously.
Figure 2-8 shows the mutagram of the composite sample of the DCM-extractable particulate
organics from the open burning of tires. This sample was acquired from the particulate filter
from the semi-volatile sampler. In general, this mutagram is similar to those generated by the
individual samples. The mutagram of the composite sample shows four main areas of
mutagenic activity, and more of the mutagenic activity is direct-acting (-S9) than S9-dependent.
In order to have adequate mass per fraction for chemical analysis, two additional
fractionations were performed, and parallel fractions were pooled; i.e., fraction 1 from run 1 was
added to fraction 1 from run 2. The solvent was evaporated from each of the 60 fractions, and
the organics were re-dissolved in DCM or acetonitrile so that adequate mass would be available
for chemical analysis. Selected mutagenic fractions were pooled to form four fractions (A-D)
that were then subjected to chemical analysis (see Table 2-2).
Because some of the PAH standards eluted in the region covered by fraction A (composed of
fractions 2 and 3 from the mutagram in Figure 2-8), fraction A was analyzed for the presence of
various PAHs. Table 2-2 shows that 14 PAHs were identified in Fraction A, confirming the
presence of this class of mutagen/carcinogen in the tire effluent. PAHs require S9 in order to be
mutagenic in Salmonella and, thus, could account for some of the mutagenic activity seen in the
presence of S9 in fractions 2 and 3 in the mutagram in Figure 2-8. However, there is also a
considerable amount of S9-independent (-S9) mutagenic activity in these two fractions that must
be due to other classes of compounds.
30
-------
HPLC Mutagram
Day 1 _sg
-B-
(0
•c
o
1 5 10 15 20 25 30 35 40 45 50 55 60
o1,000r HPLC Mutagram
Day 1
800
600
400
200
Shred
1 5 10 15 20 25 30 35 40 45 50 55 60
Fraction number
Figure 2-6. Salmonella TA98 Mutagram, Day 1 Results.
31
-------
HPLC Mutagram
Day 2
Chunk
S9
~ 0
10 15 20 25 30 35 40 45 50 55 60
HPLC Mutagram
Day 2
Shred
1 5 10 15 20 25 30 35 40 45 50 55 60
Fraction number
Figure 2-7. Salmonella TA98 Mutagram, Day 2 Results.
32
-------
1,000r
HPLC Mutagram
Composite Sample
-S9
-B-
10 15 20 25 30 35 40 45 50 55 60
Fraction number
Figure 2-8. Salmonella TA98 Mutagram, Composite Sample.
33
-------
Table 2-2. Chemicals Identified in HPLC Fractions of Participate Organics from Composite Tire
Burn Sample.
Fraction3 Chemicals
A naphthalene, fluorene, phenanthrene, fluoranthene, pyrene,
anthracene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene,
benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)-anthracene,
benzo(g,h,i)perylene, indeno(l,2,3-cd)pyrene
B nonadecane, eicosane, anthraquinone, xanthone, benzanthrone
C dioctyl phthalate
D E-caprolactam, cyclododecane, acridine, naphthalic anhydride,
benzanthrone, benzoisoquinoline, perinaphthenone, methylbenzo-
cinnoline
aFractions A-D were composed of the following fractions from the mutagram in Fig. 2-8: A
(2,3), B (22-25), C (43), and D (47-49).
Fraction B, which was composed of fractions 22,23,24, and 25 from the mutagram in Figure
2-8, contained several oxygenated PAHs, such as anthraquinone and xanthone, which are
Salmonella mutagens.32'33 Fraction C, which was composed of fraction 43 from the mutagram
in Figure 2-8, contained phthalate. However, phthalates are ubiquitous in environmental
samples and are not mutagenic in Salmonella. Thus, another class or classes of compounds is
responsible for the S9-independent mutagenic activity in fraction C. Fraction D, which was
composed of fractions 47, 48, and 49 from the mutagram in Figure 2-8, contained various
polycyclic compounds containing ring nitrogens, such as acridine, which is also mutagenic in
Salmonella. Thus, a variety of aromatic, multi-ringed mutagens are present in the particulate
organics from the open burning of tires.
Much of the mutagenic activity in the mutagram (Figure 2-8) occurred in the absence of S9,
and many nitroaromatics are mutagenic in the absence of S9. To evaluate the particulate
organics for the presence of nitroaromatics, we examined the mutagenic potency of the organics
in special strains of SalmoneUa. Strains TA98NR and TA98/1,8-DNP6 were used in conjunction
with the standard tester strain TA98 because reduced mutagenic potency in strain TA98NR
suggests the presence of mononitroaromatics; whereas, reduced mutagenic potency in strain
TA98/1,8-DNP6 suggests the presence of dinitroaromatics or other compounds that require
acetylation in order to be mutagenic. This reduced mutagenic activity occurs because strains
TA98NR and TA98/1,8-DNP6 are deficient in the nitroreductase and transacetylase enzymes,
respectively, that are necessary for the conversion of mono- and dinitroaromatics, respectively,
34
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to mutagenic electrophilic arylhydroxlyamines.34 By comparison of the mutagenic potency
obtained among the various bacterial strains, estimates can be made regarding the proportion of
the total mutagenic activity that may be attributed to mono- and dinitroaromatics.
Figure 2-9 shows the mutagenicity dose-response curves of the particulate organics in the
three strains. The mutagenic potency of the particulate organics (the slopes of the dose-
response curves) was similar in strains TA98 (-S9) and TA98NR (-S9), 0.93 and 0.86 rev/jag,
respectively. This suggests that little of the mutagenic activity of the organics was due to the
presence of mononitroaromatics. However, the mutagenic potency of the organics was reduced
by two-thirds in strain TA98/1,8-DNP6 relative to TA98,0.36 vs. 0.93 rev/ng, respectively. This
suggests that as much as two-thirds of the mutagenic activity as measured in the absence of S9
is due to the presence of dinitroaromatics or other nitroarenes or aromatic amines that require
metabolic conversion to arylhydroxylamines and then esterification in order to be mutagenic.
2.3.4 Comparison of Simulated Tire Burn to Real-World Tire Burn
At the time of the EPA study on open tire burning, a large open tire fire occurred in
Hagersville, Ontario, Canada. In February 1990, tires piled 35 ft (10.7 m) deep and covering 18
acres (72,800 m2) burned for over 2 weeks, resulting in the evacuation of hundreds of local
residents during that period. Researchers at McMaster University, Hamilton, Ontario,
transported high-volume samplers to the site and collected respirable particulate matter
downwind of the fire -1000 ft (305 m) from the burning tire dump. After only 20 hr, 330 mg of
particulate matter had been collected on two Teflon-coated glass fiber filters. Douglas Bryant of
the Biochemistry Department at McMaster University kindly provided a portion of one of the
filters to us for extraction and bioassay in order to compare the results with the EPA sample.
Figure 2-10 shows mutagenicity dose-response of the DCM-extractable particulate organics
from the Canadian tire fire in strains TA98 and TA98NR. As with the EPA sample, there was
little difference between the mutagenic potency of the Canadian sample between the two strains
(2.1 vs. 2.4 rev/|ig, respectively). Thus, similar to the EPA sample, little of the mutagenic
activity of the Canadian sample was due to mononitroaromatics. Unfortunately, we had
inadequate amounts of the Canadian sample available to evaluate it in strain TA98/1,8-DNP6.
However, results from the McMaster laboratory showed that the mutagenic potency of the
Canadian sample was reduced by as much as 50 percent in this strain relative to strain TA98 (D.
Bryant, personal communication). Thus, as with the EPA sample, much of the mutagenic
activity of the Canadian tire burn particulate organics as assayed in the absence of S9 was due to
nitroarenes or aromatic amines that required conversion to arylhydroxylamines followed by
esterification in order to be mutagenic.
35
-------
300 r
250
EPA Tire Burn
Composite Sample
Piate Assay
TA98 (+S9)
TA98/1,8-DNFfc (-S9)
40 60
Dose (gg/plate)
80
100
Figure 2-9. Salmonella TA98 Dose-Response Curves, Composite Sample.
36
-------
200
150
100
O
2s
a
50
Hagersville, Ontario, Tire Burn
Expt. 1
TA98 (+S9)
TA98 (-S9)
TA98NR (-S9)
£ 0
(0
t
o
§300
oc
200
10
20
30
40
Hagersville, Ontario, Tire Burn
Expt. 2
TA98 (-S9)
50
TA98NR (-S9)
100
TA98 (+S9)
0
0
50 100 150
Dose (jjg/plate)
200
Figure 2-10. Salmonella TA98 Dose-Response Curves, Ontario Tire Burn Sample.
37
-------
Note that the mutagenic potency of both the EPA and Canadian particulate organics was
similar when evaluated after a similar time in storage at -80 °C However, the mutagenic
potency of both samples declined during the months of storage. During the course of 1 year, as
much as 50 percent of the mutagenic activity was lost from both samples, suggesting the
presence of unstable, short-lived mutagenic species in the mixtures. Similar results have been
found for other types of combustion emissions, such as cigarette smoke. Interestingly, much of
the mutagenic activity of such emissions is due to the presence of aromatic amines. In contrast,
the mutagenic potency of the particulate organics from diesel exhaust is highly stable over
many years of storage and the emissions contain little aromatic amines. The mutagenic activity
of diesel exhaust is due largely to mononitroaromatics, which are clearly not responsible for
much of the mutagenic activity of the tire burn particulate organics or of other combustion
emissions that exhibit unstable mutagenic activity during storage.
In order to see if the mutagenic activity of the Canadian sample would fractionate in a
manner similar to that of the EPA sample, the remaining portion of the DCM particulate extract
of the Canadian sample was fractionated by HPLC in a manner identical to that used for the
EPA sample. The resulting mutagram (Figure 2-11) shows some similarities to the mutagram of
the EPA composite sample (Figure 2-8). In particular, peaks of mutagenic activity are clearly
evident in the first few fractions, which represent PAHs. In addition, there is a strong peak of
direct-acting (-S9) mutagenic activity in fraction 40, which is similar in location (fraction 43) to
direct-acting mutagenic activity in the mutagram of the EPA composite sample.
Other areas of the mutagram of the Canadian sample show only slight elevations in
mutagenic activity and a generally elevated base line of mutagenic activity. This may be due to
the presence of compounds that were formed by atmospheric transformation. Such mutagens
would not be present in the EPA sample because that burn was conducted within a small
building in the absence of sunlight, and the sample was collected near the burn. Note that the
overall mutagenic potency of the Canadian sample (as seen from the y-axis scale) is one-third
that of the EPA sample (Figure 2-8). This is most likely because the Canadian sample had lost
much of its mutagenic activity by the time we fractionated it. This reduced overall mutagenic
potency reduced the ability to identify mutagenic activity in other potentially mutagenic
fractions.
Despite the limitations of sample age, the mutagenic profiles of the EPA and Canadian
samples are similar based on mutagenic potency in various tester strains and the HPLC-
generated mutagram. In addition, chemical analysis of the whole DCM extract of the Canadian
sample by researchers at McMaster University has identified many of the same chemicals at
similar relative concentrations as were found by us in the EPA tire burn sample. Based on these
chemical and biological measurements, it appears that the EPA tire burn simulated reasonably
38
-------
well a major real-world tire burn of the type experienced in Hagersville, Ontario. This
conclusion should provide some confidence in extrapolating from the EPA simulated tire burn
to real-world tire burns.
350
300
fl)
O 250
HPLC Mutagram
Hagersville Sample
TA98 (+S9)
TA98 (-S9)
15 20 25 30 35 40 45 50 55 60
Fraction number
Figure 2-11. Salmonella TA98. Mutagram, Ontario Tire Burn Sample.
39
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2.4 SUMMARY AND CONCLUSIONS
In general, the mutagenic potency of the semi-volatile organics (those collected on XAD
resin) was similar for CHUNK or SHRED tires. However, the mutagenic potency of the
particulate organics (those collected on filters) was 2-10 times greater than that of the semi-
volatile organics. CHUNK tires produced more potent organics as assayed in the presence of
S9, but SHRED tires produced more potent organics as assayed in the absence of S9. This
difference is a reflection of the different classes of chemical mutagens that likely were produced
under the two combustion conditions. Based on additional data, these results suggest that the
particulate organics from CHUNK tires contain more PAHs than are present in the effluent
produced by SHRED tires. This is likely due to the greater initial burn rate that was achieved
with CHUNK tires, leading to the production of PAHs.
In general, the mutagenic emissions factors (revertants/kilogram of tires or
revertants/megajoule of heat) were similar for the semi-volatile organics produced by CHUNK
or SHRED tires as assayed in the presence or absence of S9. The mutagenic emission factors for
the particulate organics were much greater than those for the semi-volatile organics. The vast
majority of the mutagenic activity as measured by the mutagenic emission factors derived from
the DCM-extractable particulate organics as opposed to the semi-volatile organics.
The average of the CHUNK and SHRED particulate mutagenic emission factor for the open
burning of tires as assayed in strain TA98 in the presence of S9 was compared to that of other
combustion emissions. The results showed that the mutagenic emission factor for open tire
burning is the greatest of any other combustion emission studied previously. For example, it is
3-4 orders of magnitude greater than the mutagenic emission factors for the combustion of oil,
coal, or wood in utility boilers.
Interestingly, the mutagenic emission factor for the open burning of tires was most similar
to the values for the open burning of wood (in residential fire places) and plastic (in agricultural
fields). These open burning conditions are characterized by poor combustion parameters,
resulting in elevated levels of PICs and, thus, elevated mutagenic emission factors. Open
burning, regardless of the feed stock or fuel, appears to result in greater mutagenic emission
factors than does controlled combustion as provided by various types of incinerators or boilers.
The HPLC-generated mutagrams were similar for the particulate organics resulting from the
open burning of either CHUNK or SHRED tires. This suggests that there were only minor
differences in the chemical composition of the two effluents. Chemical analysis of selected
mutagenic HPLC fractions identified PAHs has a major contributor to the mutagenic activity of
the organics. In addition, oxygenated PAHs, such as anthraquinone, and various aromatic
compounds that contained ring nitrogens, such as acridine, were also present in mutagenic
fractions.
40
-------
The mutagenic potency of the unfractionated particulate organics in various strains of TA98
in the absence of S9 showed that little of the mutagenic activity was due to mononitroaromatics,
but as much as two-thirds of the mutagenic activity (in the absence of 59) was due to either
dinitroaromatics or other types of nitroarenes or aromatic amines that require metabolic
conversion to arylhydroxylamines and then esterification in order to be mutagenic.
Through the auspices of colleagues at McMaster University in Hamilton, Ontario, Canada,
we were able to obtain samples of particulate organics from the effluent of a large open tire
burn that occurred during 2 weeks in Hagersville, Ontario, in February 1990. This real-world
sample had a mutagenic potency similar to the EPA sample. In addition, the mutagram
contained several of the same'mutagenic fractions (particularly the PAH-containing fraction) as
the EPA mutagram, and the Canadian sample also showed evidence that various types of
nitroarenes or aromatic amines were present as in the EPA sample. Chemical analysis also
showed great similarity between the Canadian and EPA samples. Based on these chemical and
biological measurements, the EPA tire burn simulated reasonably well a major real-world tire
burn of the type experienced in Hagersville, Ontario. This conclusion should provide some
confidence in extrapolating from the EPA simulated tire burn to real-world tire burns.
Considering (a) the relatively high mutagenic potency of the particulate organics, (b) the
high mutagenic emission factors, and (c) the presence of many mutagens/carcinogens,
especially PAHs, in the effluent from the open burning of tires, such burns pose a genuine
environmental and health hazard. Because of the frequent occurrence of unwanted combustion
at tire piles, and the potential environmental and health risks posed by such combustion,
prudence would suggest that such piles be reduced or eliminated in size and number. Used
tires may be recycled, used in asphalt for roads, or incinerated under controlled conditions in
combustion devices for cogeneration of power. Any of these uses would appear to be
preferable to the environmental and health risks posed by the open burning of tires.
41
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REFERENCES
1 Sladek, T.A. Workshop on Disposal Techniques with Energy Recovery for Scrapped
Vehicle Tires. City and County of Denver, The Energy Task Force of the Urban Consortium for
Technology Initiatives, U.S. Department of Energy, Denver, CO, 101 pp, February 1987.
2 Kearney, A.T. Scrap Tire Use/Disposal Study, Prepared for the Scrap Tire Management
Council, September 1990.
3 Clark, C, K. Meardon, and D. Russell Burning Tires for Fuel and Tire Pyrolysis: Air
Implications. EPA-450/3-91-024, December 1991.
4 Pirnie, M. Air Emissions Associated with the Combustion of Scrap Tires for Energy
Recovery, Prepared for the Ohio Air Quality Development Authority, May 1991.
5 Section 1038, H.R. 2950 Intermodal Surface Transportation Efficiency Act of 1991. First
Session of the 102nd Congress. Enacted December 18,1991.
6 Haverfield, L.E. and B.L. Hoffman "Used tires as a Means of Dispersal of Aedes aegypti
in Texas." Mosq. Neivs, 26:433-5,1966.
7 Miller, R.D. "Managing Scrap Tires: What Role Should State and Local Government
Play?" In Workshop on Disposal Techniques with Energy Recovery for Scrapped Vehicle Tires,
City and County of Denver, The Energy Task Force of the Urban Consortium for Technology
Initiatives, U.S. Department of Energy, Denver, CO, February 1987.
8 Ryan, J.V. Characterization of Emissions from the Simulated Open Burning of Scrap
Tires, EPA-600/2-89-054 (NTIS PB90-126004), October 1989.
9 Method 0030 in SW-846 (NTIS PB88-239223) Test Methods for Evaluating Solid Wastes.
Vol. II, Field Manual Physical/Chemical Methods, EPA, November 1986.
10 Schulman, B.L. and P.A. White "Pyrolysis of Scrap Tires Using the TOSCO II Process - A
Progress Report." Reprint from the ACS Symposium Series, #76, Solid Wastes And Residues,
1978.
11 National Institute for Occupational Safety and Health (NIOSH), Health Hazard
Evaluation Report, Rhinehart Tire Fire. Winchester, Virginia. HETA 84-049-1441, March 1984.
12 International Agency for Research on Cancer (IARC), Monograph Programme on the
Evaluation of Carcinogenic Risk of Chemicals to Humans, Polynuclear Aromatic Compounds.
Part 4, Bitumens, Coal-tar and Derived Products, Shale Oils and Soots, Vol. 35, IARC, Lyon,
France, 1985.
42
-------
13 Lewtas, J. "Genotoxicity of Complex Mixtures: Strategies for the Identification and
Comparative Assessment of Airborne Mutagens and Carcinogens from Combustion Sources,"
Fundam. Appl. Toxicol. 10:571-589,1988.
14 Schuetzle, D. and J. Lewtas "Bioassay-Directed Chemical Analysis in Environmental
Research," Anal. Chem. 58,1060A-1075A, 1986.
15 Lewtas, J. "Mutagenic Activity of Diesel Emissions," In (Lewtas, J., Ed.) Toxicology
Effects of Emissions from Diesel Engines, Elsevier Science, New York, pp. 243-264,1982.
16 Tokiwa, H., R. Nakagawa, and K. Horikawa "Mutagenic/Carcinogenic Agents in Indoor
Pollutants; the Dinitropyrenes Generated by Kerosene Heaters and Fuel Gas and Liquified
Petroleum Gas Burners," Mutat. Res. 157:39-47,1985.
17 Lewtas, J., J. Chuang, M. Nishioka, and B. Petersen "Bioassay-Directed Fractionation of
Organic Extract of SRM 1649 Urban Air Particulate Matter," Intern. J. Environ. Anal. Chem.
39:245-256,1990.
18 Bell, D.A., H. Karam, and R.M. Kamens "Nonaqueous Ion-Exchange Separation
Technique for Use in Bioassay-Directed Fractionation of Complex Mixtures: Application to
Wood Smoke Particle Extracts," Environ. Sti. Technol. 24:1261-1264,1990.
19 DeMarini, D.M., R.W. Williams, L.R. Brooks, and M.S. Taylor "Use of Cyanopropyl-
Bonded Silica for Bioassay-Directed Fractionation of Organic Extracts from Incinerator
Emissions," Intern. J. Environ. Anal. Chem., in press, 1992.
20 DeMarini, D.M., R.W. Williams, E. Perry, P.M. Lemieux, and W.P Linak "Bioassay-
Directed Chemical Analysis of Organic Extracts of Emissions from a Laboratory-Scale
Incinerator: Combustion of Surrogate Compounds," Combust. Sti. Technol., in press, 1992.
21 DeMarini, D.M., V.S. Houk, J. Lewtas, R.W. Williams, M.G. Nishioka, R.K. Srivastava,
J.V. Ryan, J.A. McSorley, R.E. Hall, and W.P. Linak "Measurement of Mutagenic Emissions from
the Incineration of the Pesticide Dinoseb during Application of Combustion Modifications,"
Environ. Sci. Technol. 25:910-913,1991.
22 Linak, W.P., J.A. Mulholland, J.A. McSorley, R.E. Hall, R.K. Srivastava, J.V. Ryan, M.G.
Nishioka, J. Lewtas, and D.M. DeMarini "Application of Staged Combustion and Reburning to
the Co-firing of Nitrogen-Containing Wastes," Hazard. Waste & Hazard. Materials 8:1,1-15,1991.
23 International Agency for Research on Cancer (IARC), Monograph Programme on the
Evaluation of Carcinogenic Risk nf chemicals to Humans. The Rubber Industry, Vol. 28. IARC,
Lyon, France, 1982.
43
-------
24 International Agency for Research on Cancer (IARC), Monograph Programme on the
Evaluation of Carcinogenic Risk of Chemicals to Humans. Some Chemicals Used in Plastics and
Elastomers, Vol. 39. I ARC, Lyon, France, 1986.
25 Shibamoto, T., and C.-I. Wei "Mutagenicity of Materials Extracted from Synthetic
Rubber," Agric. Biol. Chem. 50:513-514,1986.
26 Rannug, A.H., and C. Ostman "Application of Mutagenicity Tests for Detection and
Source Assessment of Genotoxic Agents in the Rubber Work Atmosphere," in: Waters, M.D.,
Sandhu, S.S., Lewtas, J., Claxton, L., Chernoff, N., and Nesnow (Eds.) Short-Term Bioassavs in
the Analysis of Complex Environmental Mixtures III, Plenum Press, New York, pp 541-553,
1983.
27 Maron, D.B., and B.N. Ames, "Revised Methods for the Salmonella Mutagenicity Test,"
Mutat. Res., 113:173-215,1983.
28 Thilly, W.G., J. Longwell, and B. Andon "General Approach to the Biological Analysis of
Complex Mixtures," Environ. Health Perspect., 48:129-136,1983.
29 Lewtas, J., L.C. King, K. Williams, L.M. Ball, and D.M. DeMarini "Bioassay-Directed
Fractionation of 1-Nitropyrene Metabolites: Generation of Mutagrams by Coupling Reverse-
Phase HPLC with Microsuspension Mutagenicity Assays," Mutagemsis, 5:481-489,1990.
30 Lewtas, J., S. Goto, K. Williams, J.C. Chuang, B.A. Peterson, and N.K. Wilson "The
Mutagenicity of Indoor Air Particles in a Residential Pilot Field Study: Application and
Evaluation of New Methodologies," Atmos. Environ., 21:443-449,1987.
31 Fernandez, P., M. Grifoll, A.M. Solanas, J.M. Bayona, and J. Albaiges "Bioassay-Directed
Chemical Analysis of Genotoxic Components in Coastal Sediments," Environ. Sci. Technol,
26:817-829,1992.
32 Zeiger, E., B. Anderson, S. Haworth, T. Lawlor, and K. Mortelmans "Salmonella
Mutagenicity Tests: IV. Results from the Testing of 300 Chemicals," Environ. Mol. Mutagen.,
ll(Suppl. 12):1-158,1988.
33 Muramatsu, M., and T. Matsushima "Metabolic Activation Systems for Hydroxyl
Derivatives of Anthraquinone and Xanthone," Mutat. Res., 164:274,1986.
34 McCoy, E.C., M. Anders, and H.S. Rosenkranz "The Basis of the Insensitivity of
Salmonella typhimurium Strain TA98/1,8-DNP6 to the Mutagenic Action of Nitroarenes,"
Mutat. Res., 121:17-23,1983.
44
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APPENDIX A: QUALITY ASSURANCE
This QA narrative will be used to describe major components of sample handling and
analysis.
A-l. Sample Preparation
Sample preparation would include such work tasks as solvent concentration, dilution,
filtering, and standard solution preparation.
Samples were received into the laboratory and stored in their original containers at -30 °C in
darkness. Glassware and laboratory apparatus to be used in sample preparation procedures
was first washed with an appropriate organic solvent, rinsed with alcohol, and then washed
with a surfactant. Distilled-deionized water rinses were then employed to remove any residue.
Glassware was then heated to >250 °C for 2 hours. Cooled glassware was then rinsed with the
organic solvent of choice just prior to study use. All materials were either borosilicate glass,
Teflon, or stainless steel. Solvents utilized in the study were spectroscopic grade from one
vendor. Only one lot of each solvent was used during study tasks. Appropriate blank analyses
were performed (HPLC with UV detection) to document solvent artifact levels.
Gravimetric analyses were performed on selected samples. This was conducted when mass
specific results (revertants/|ig, HPLC mass recovery/fractions, etc) had to be obtained.
Calibrated transfer devices (syringes, pipets, etc) were employed to remove a known volume of
aliquot liquid and transfer it to a tared aluminum weigh pan. This analysis was conducted with
replicates (usually a total of three trials) and the mean mass determined after equilibration of
the dried residue under desiccation. All weighing involved a lug-readable balance audited
prior to use.
A-2. Gas Chromatography
Bonded-phase capillary columns were employed in GC analysis of tire burn fractions.
Installed columns were audited for inertness and reactivity using a standardized "Grob"
mixture. This mixture contains polar and nonpolar compounds, and organic acids and bases.
Only columns successfully shown to be acceptably inert were utilized. Heated instrument
zones (column oven, injectors, detectors) were audited for temperature accuracy against set
points at 6 month intervals. Gas flows (carrier, makeup, detector, etc) were optimized for best
instrument performance and audited prior to use. Linearity of the detector was shown to be
beyond concentrations levels encountered within the study. Standards were injected under
exact operating conditions as the fractions of interest. Retention time indices were determined
to use as reference values for tentative peak identifications.
45
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A-3. High Pressure Liquid Chromatography
HPLC columns were employed in the bioassay-directed fractionation of the tire burn
extracts. Aliquots of known mass and concentrations were injected into the HPLC system and
eluted using an optimized gradient program. Quality Assurance procedures included solvent
cleansing of the injection loop before and after each injection (to remove cross-contamination
concerns), along with auditing of pump flow rates and column pressures versus historical
records. Standardized programming of detectors, gradient controllers, timed events, and
fraction collector control was verified by a 2nd party prior to use. Gradient curves are run
systematically to verify gradient composition of programmed runs. Method blanks, standards,
and tire burn extracts were analyzed on 1 day by the same technician on one instrument.
Replicate analyses of the tire burn extract (usually three trials) were conducted. Inertness of .the
HPLC column to the species present in the tire burn extract was determined by injecting known
mass aliquots into the system and recovering the mass using gradient programming. The
recovered mass (corrected for method blanks) was then compared to theoretical injection mass.
Greater than 90 percent of injected mass under the analysis conditions was found to be
recovered. This value also demonstrated that mass could be recovered after HPLC analysis
without appreciable loss.
Individual fractions of the tire burn were captured to document bioassay-directed
fractionation efforts. Known amounts of extract were injected into the HPLC with resulting
fractions captured in time-specific windows. The transfer of fluid (solute residing in HPLC
solvent) was time audited to ensure that individual peaks eluting at specific tune points could
be assured of being present in solvent-cleaned borosilicate glass fraction vials. Each vial was
pre-numbered prior to the analysis and placed on the fraction collector. Second party auditing
of vial location as well as label contents was conducted prior to fractionation. Replicate
analyses were conducted to be used in multiple bioassays.
46
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing]
1. REPORT NO.
EPA-600/R-92-12 7
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Mutagenicity of Emissions from the Simulated Open
Burning of Scrap Rubber Tires
5. REPORT DATE
July 1992
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Paul M. Lemieux (EPA/AEERL) and David M.
DeMarini (EPA/HERL)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
See Block 12
11. CONTRACT/GRANT NO.
NA (Inhouse)
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 1/89 - 5/92
14. SPONSORING AGENCY CODE
EPA/600/13
15.SUPPLEMENTARY NOTES AEERL project officer is Paul M. Lemieux, Mail Drop 65, 919/
541-0962. Coauthor David M. DeMarini's Mail Drop is 68A; his phone number is
919/541-1510.
16. ABSTRACT
The report describes a follow-up to a small-scale combustion study to col-
lect, identify, and quantify products emitted during the simulated open combustion of
scrap tires. The initial study found that total estimated emissions of semi-volatile
organics ranged from 10 to 50 g/kg of tire material burned. Mono- and poly-aromatic
hydrocarbons were the predominant emission products identified. The follow-up
study subjected the extracts from the initial study to bioassay-directed fractionation
to determine mutagenic potencies of the extracts. The results from the bioassay
studies were then compared to data from other conventional combustion sources to
indicate the relative potencies of the emissions from uncontrolled burning of tires.
The fractionated extracts were then subjected to further gas chromatography/mass
spectroscopy (GC/MS) analysis to determine the classes of compounds giving the
highest mutagenic potencies. In addition, a sample from an actual tire burn was sub-
jected to the same bioassay analyses to determine the relevance of the initial small-
scale simulations to actual field samples from a full- scale tire fire.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Tires
Combustion
Emission
Organic Compounds
Mutagens
Gas Chromatography
Mass Spectroscopy
Scrap
Pollution Control
Stationary Sources
Scrap Rubber
13B
13F
21B
14G
07C
06E
DTD"
14B
11G
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport}'
Unclassified
21. NO. OF PAGES
53
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
47
EPA - RTF LIBRARY
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