vvEPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(OS-305)
EPA/530-SW-90-029B
March 1990
Characterization of
Municipal Waste
Combustion Ash,
Ash Extracts, and Leachates
Executive Summary
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Printed on paper that contains at least 50 percent recycled fiber.
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EXECUTIVE SUMMARY
This report has been prepared for the United States Environmental Protection
Agency (EPA) and the Coalition on Resource Recovery and the Environment (CORRE).
EPA and CORRE have cosponsored this study, conducted by NUS Corporation, to
enhance the data base on the characteristics of Municipal Waste Combustion (MWC)
ashes, laboratory extracts of MWC ashes, and leachates from MWC ash disposal
facilities.
The Coalition on Resource Recovery and the Environment (CORRE) was established
to provide credible information about resource recovery and associated
environmental issues to the public and to public officials. In providing information,
CORRE takes no position as to the appropriateness of one technology compared to
others. CORRE recognizes that successful waste management is an integrated
utilization of many technologies which taken as a whole, are best selected by an
informed public and informed public officials.
Incineration of municipal solid waste (MSW) has become an important waste
disposal alternative because it provides an effective means of reducing the volume
of MSW as well as an important source of energy recovery. .Currently, 10 percent of
MSW is incinerated. Based on the number of municipal waste combustion (MWC)
facilities being planned across the country, this percentage is expected to increase to
roughly 16-25 percent by the year 2000.
As incineration has grown in popularity, so has concern over the management of
increasing volumes of ash. Ashes from MWC facilities have, on occasion, exhibited a
hazardous waste characteristic as determined by the EP Toxicity Test. The debate
regarding the regulatory status of ash and the representativeness and validity of the
EP test continues. Congress is considering several legislative initiatives that would
give EPA clear authority to develop special management standards for ash under
Subtitle D of RCRA.
To conduct this study, NUS collected combined bottom and fly ash samples from five
mass-burn MWC facilities and leachate samples from the companion ash disposal
facilities.
R339911
ES-1
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The facilities sampled were selected by CORRE to meet the following criteria:
The facilities were to be state-of-the-art facilities equipped with a variety of
pollution control equipment.
The facilities were to be located in different regions of the United States.
The companion ash disposal facilities were to be equipped with leachate
collection systems or some means of collecting leachate samples.
The identities of the facilities are being held in confidence.
The ash and leachate samples collected were analyzed for the Appendix IX
semivolatile compounds, polychlorinated dibenzo-p-dioxins/polychlorinated
dibenzofurans (PCDDs/PCDFs), metals for which Federal primary and secondary
drinking water standards exist, and several miscellaneous conventional compounds.
In addition, the ash samples were analyzed for major components in the form of
oxides. The ash samples were also subjected to six laboratory extraction procedures
and the extracts were then analyzed for the same compounds as the ash samples.
The following six extraction procedures were used during this study:
Acid Number 1 (EP-TOX),.
Acid Number 2 (TCLP Fluid No. 1).
Acid Number 3 (TCLP Fluid No. 2).
Deionized Water (Method SW-924), also known as the Monofill Waste
Extraction Procedure (MWEP).
CQ2 satu rated deionized water.
Simulated acid rain.
These extraction procedures have been used separately by a variety of researchers on
MWC ashes but never have all six procedures been used on the same MWC ashes.
This study was designed to compare the analytical results of the extracts from all six
procedures with each other and with leachate collected from the ash disposal
facilities used by the MWC facilities.
R339911 ES-2
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All sampling, laboratory preparation, and laboratory analysis followed stringent EPA
quality assurance/quality control (QA/QC) procedures. The work was performed in
accordance with the Work Plan (Appendix A) prepared by NUS for this project and
with a QA/QC Plan prepared by NUS and approved by EPA. A detailed listing of the
positive results is presented in a data base which is included in this Report as
Appendix B (Ash), Appendix C (Leachate), and Appendix D (Ash Extracts). The results
in the data base are presented as reported by the laboratories, complete with the
laboratory's qualifications. Summaries of the results are presented in Sections 2.0
through 7.0. These summaries include the laboratory's qualifiers and also qualifiers
placed on the data as a result of data validation.
When the laboratories did not report a positive value for a compound (i.e., the
compound was not present above laboratory detection limits), the compound was
reported as not detected (ND) in the tables in the text. The laboratory detection
limits are the method detection limits for each specific method, unless interferences
were encountered during the analysis. When interferences occurred, the laboratory
adjusted the method detection jimits by an appropriate dilution factor. The
analytical methods used in this study were selected so that.the method detection
limits were well below present levels of human, environmental, or regulatory
concerns.
The EPA publication "Interim Procedures for Estimating Risk Associated with
Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans (CDDs
and CDFs)" was used to evaluate the dioxin data. These procedures use Toxicity
Equivalency Factors (TEFs) to express the concentrations of the different isomers and
homologs as an equivalent amount of 2,3,7,8-Tetrachloro Dibenzo-p-Dioxin
(2,3,7,8-TCDD). The Toxicity Equivalents, as calculated by using the TEFs, are then.
totaled and compared to the Centers for Disease Control (CDC) recommended upper
level of 2,3,7,8-TCDD Toxicity Equivalency of 1 part per billion in residential soil
(Kimbrough, 1984).
The major features of the five MWC facilities are provided in Table ES-1, and the
major features of the MWC Ash Disposal Facilities are provided in Table ES-2,
Pertinent information regarding the operating conditions of the MWC facilities, as
well as information about the air pollution control equipment used by the facilities,
is also provided in Table ES-1.
R339911
ES-3
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30
to
U)
TABLE ES-1
MAJOR FEATURES OF MWC FAQLITIES
Operational
Features
Facility Type
Startup Date
Capacity
Combustion
Temperature
Temperature of
air entering the
boiler
Volume of air
entering boiler
C«i»i«-*-ja f\f act*
quench water
Air pollution
control
equipment
Approximate
waste
composition
ZA
Energy recovery,
continuous feed, reverse-
reciprocating grate.
May 1986
275 tons/day/boiler
2 boilers
1,800-2.000°F at stoker
Under fire: 250°F
Over fire: ambient
Under fire:
70,000-90,000 Ib/hour
Over fire:
41,000 Ib/hour
Clr\s\r rtr^ine mln t*i^+t*r
Lime slurry is injected
into flue gas after
economizer, fabric filter
baghouses.
Residential: 40%
Commercial/
Light Industrial: 60%
ZB
Energy recovery,
continuous feed,
reciprocating grate.
Early 1987
75 - 100 tons/day/boiler
2 boilers
1,800°F
Under fire: ambient
Over fire: ambient
Under fire:
1 0,890 cuft/min
Over fire:
5,900 cu ft/min
/VhAt tit A +A»*4A.- vnj-J U.A;IA^
blowdowns, septic system
discharge, floor drains.
Dry lime is injected into flue
gas after economizer, fabric
filter baghouses.
Fly ash has phosphoric acid
added to it and is
agglomerated before being
mixed with bottom ash.
Residential: 80%
Commercial/
Light Industrial: 20%
Facilities
ZC
Energy recovery,
continuous feed, reverse-
reciprocating grate.
January 1987
400 tons/day/boiler
3 boilers
1,750-1.800°F
Under fire: 380°F
Over fire: ambient
Under fire:
34,000 ft3/min
Over fire:
11,000ft3/min
T^.^;-..,., «.«{!. .,»+ *,^_
neighboring sewage
treatment plant.
Electrostatic
precipitators.
Residential: 60%
Commercial/
Light Industrial: 40%
ZD
Energy recovery,
continuous feed,
reciprocating grate.
1975
750 tons/day/boiler
2 boilers
1 500-1 700UF flue gas as it
enters superheater
Under fire: ambient
Over fire: ambient
Under fire:
48,000 ft3/m in
Over fire:
32,000 ft3/min
/- I' J U -1
blowdowns.
Electrostatic precipitators
Residential: 90%
Commercial/
Light Industrial: 10%
ZE
Energy recovery,
continuous feed,
reciprocating grate.
September 1987
75^ tons/day/boiler
2 boilers
1,800°F at the grate
Under fire: ambient
Over fire: ambient
../ . t .
vvasiewdier irom piani
processes.
Lime slurry is injected into
flue gas after economizer,
electrostatic precipitators.
Fly ash has water added to
it and is agglomerated
before being mixed with
bottom ash.
Residential: 65%
Commercial/
Light Industrial: 35%
I/I
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TABLE ES-1
MAJOR FEATURES OF MWC FACILITIES
PAGE TWO
Operational
Features
Amount of
electricity
generated
Amount of
electricity used
internally by
facility
Material
removed from
incoming refuse
Material
removed from
ash
Facilities
ZA
13.1 megawatts/hour
1.7 megawatts/hour
Large appliances, other
unacceptable material
diverted to demolition
landfill.
Ferrous metal removed
from ash at the MWC
facility.
ZB
4.5 megawatts/hour
0.63 megawatts/hour
Large appliances, material
that will not pass through
the boilers.
None.
ZC
29 megawatts/hour
2.5 megawatts/hour
Large appliances,
material that will not
pass through the boilers.
Ferrous metal removed
from ash at the MWC
facility.
ZD
35 megawatts/hour
2.5 to 3.5
megawatts/hour
Large appliances,
material that wilt not
pass through the boilers.
Ferrous metal removed
from ash at the MWC
facility.
ZE
45 megawatts/hour
7 megawatts/hour
Large appliances, material
that will not pass through
the boilers.
Items greater than
10 inches in diameter,
m
v>
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U>
ID
TABLE ES-2
MAJOR FEATURES OF MWC ASH DISPOSAL FACILITIES
Operational
Features
Facility Type
Startup Date
Disposal Capacity
Amount of Ash
Disposed
Materials other
than Ash
disposed of
Leachate
Collection System
Ash
ZA
Monofill - single clay
liner
1986
83.400 cubic yards
150 tons/day .
None
Perforated PVC pipe in a
coarse aggregate
envelope
Final cover -soil and
HOPE
Only as bulldozer spreads
ash in ash fill.
Facilities
ZB
Monofill - double liner
(HOPE and compacted till
soil)
October 1988
90,000-100,000 tons
60 tons/day
None
Slotted HOPE
Daily cover - sand. Non
working face covered by
plastic to limit leachate
generation
Bulldozer spreads and
compacts ash in 8- 1 2 inch
ifts.
ZC
Codisposed facility -
bottom-clay liner
synthetic sidewall liners
Landfill -1984
Ash Disposal- 1985
Total capacity 9 million
tons
400,000 tons/year.
40% ash (2/3 of ash from
ZC MWC facility).
Non-burnable materials
from 2 MWC facilities.
Overflow from 2nd MWC
facility.
Main header - PVC
collection trenches -
gravel with fabric filter
Daily -native soil and
shredded tires.
ntermediate - native
soils.
inal - native soils.
Track mounted
compactor.
ZD
Monofill - unlined. Ash is
placed over trash
deposited before 1975
1975
Remaining capacity -
990,000 tons (6 years)
450 tons/day
None
None - leachate samples
were'collected from well
points installed in the ash
Daily cover -soil.
Intermediate -soil
compacted to 10-fi
Dermeability.
:inal- clay or HOPE.
Only as bulldozer spreads
ash in ash fill.
ZE
Monofill - double liner
(HOPE and clay)
1987
Pe ..utted for 20 years,
approximately 3.8 million
tons
525 tons/day
None
Slotted HOPE
Daily cover -soil.
Intermediate -soil
compacted to 10'6
Jermeability.
Final -clay of HOPE
Vibrating roller.
i
m
t/>
a\
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The major findings of the ash sampling and analyses.during this study are described
in the following paragraphs.
Of the five ash samples (one from each facility) analyzed for the Appendix IX
semivolatile compounds, four samples contained bis(2-ethylhexyl)phthalate, three
contained di-n-butyl phthalate, and one contained di-n-octyl phthalate. Two PAHs,
phenanthrene and fluoranthene, were detected in only one of the five ash samples.
These semi-volatile compounds were detected in the parts per billion (ppb) range.
The results for the five ash samples (one from each facility) analyzed for
PCDDs/PCDFs are presented in Table ES-3. This table also includes the calculated
Toxicity Equivalents (TE) for each homolog of PCDD/PCDF. These TEs were calculated
using EPA's methodology (EPA, March 1987). The data in this table indicate that
PCDDs/PCDFs were found at extremely low levels in each ash sample. The Total TE
for each ash sample was below the Centers for Disease Control (CDC) recommended
2,3,7,8-TCDD Toxicity Equivalency limit of 1 part per billion in residential soil
(Kimbrough, 1984).
All 25 of the ash samples (five daily composites from each facility) were analyzed for
the metals on the primary and secondary drinking water standards lists as well as for
the oxides of five major ash components. Although, the results from these analyses
indicate that the ash is heterogeneous, this heterogenicity appears to have been
reduced by the care taken when compositing the ash samples during this study.
Comparison of the results of this study with results reported in the literature (EPA,
October 1987) indicates that the variability of results for each compound appears to
have been reduced in this study.
Metals showing the widest range of concentrations among samples collected at each
facility included barium (ZB); cadmium (ZB); chromium (ZD, ZE); copper (ZA, ZB, ZC);
lead (ZD); manganese (ZA, ZC); mercury (ZE); zinc (ZB, ZD, ZE); and silicon dioxide
(ZA).
Metals showing the widest variation of concentrations between the facilities
included barium (results for Facility ZC are lower than the results for the other
facilities); iron (results for each facility vary from all of the other facilities); lead
(results for Facility ZD are higher than the results for the other facilities); mercury
(results for Facilities ZC and ZD are lower than the results for the other facilities);
R339911 ES-7
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30
U>
U)
TABLE ES-3
ASH DIOXIN RESULTS
Compound
2,3,7,8-TCDD
Other TCDD
2,3,7,8-TCDF
Other TCDF
1,2,3.7,'8-PeCDD
Other PeCDD
1.2,3,7,8-PeCDF
2.3.4.7,8-PeCDF
Other PeCDF
1,2,3,4,7,8-HXCDD
1,2,3,6,7.8-HxCDD
1,2,3,7,8.9-HXCDD
Other HXCDD
1,2,3,4,7.8-HXCDF
1. 2,3,6, 7.8-HxCDF
1,2,3,7,8,9-HXCDF
2,3A3.7,8-HXCDF
Other HXCDF
1,2,3,4,6,7,8-HpCDD
Other HpCOD
1, 2,3,4,6, 7,8-HpCDF
123478 9-HpCDF
Other HpCDF
OCDD
OCDF
TOTAL TEs
Toxicity
Equivalency
Factor
(TEF)0>
1
0.01
0.1
0.001
0.5
0.005
01
0.1
0.001
0.04
0.04
0.04
0.0004
0.01
0.01
0.01
0.01
0.0001
0.001
0.00001
0.001
0 001
0.00001
0
. 0
Samples (pg/g or ppt)
ZA-AH-003
Value
10
206
263
1,688
33
317
61
46
484
12
17
28
154
74
131
36
5
281
159
140
139
g
51
313
66
Toxicity
Equivalents
10
2.06
26.3
.1.69
16.5
1.59
6.1
4.6
0.484
0.48
0.68
1.12
0.062
0.74
1.31
0.36
0.05
0.0281
0.159
0.0014
0.139
0 008
0.00051
0
0
74.5
ZB-AH-001
Value
24
351
617
3,721
118
759
194
162
1,527
40
34
79
342
336
524
127
54
939
319
288
539
4R
197
544
243
Toxicity
Equivalents
24
3.51
61.7
3.72
59
3.80
19.4
16.2
1.53
1.6
1.36
3.16
0.137
3.36
5.24
1.27
0.54
0.0939
0.319
0.00288
0.539
OfldR
000197
0
0
211
ZC-AH-003
Value
16
281
236'
1,208
71
1,051
64
56
607
66
90
120
925
218
279
193
70
635
1,849
1,511
653
R3
254
6,906
563
Toxicity
Equivalents
16
2.81
23.6
1.21
35.5
5.26
6.4
5.6
0.607
2.64
3.6
4.8
0.37
2.18
2.79
1.93
0.70
0.0635
1.85
0.0151
0.653
A nft3
0 00254
0
0
119
ZD-AH-003
Value
35
541
626
2,633
NO
1,910
151
171
1,736
86
148
194
853
654
660
479
124
1,686
1.555
1,384
1,842
384
4,519
893
-- - -
Toxicity
Equivalents
35
5.41
62.6
2.63
0
9.55
15.1
17.1
1.74
3.44
5.92
7.76
0.34
6.54
6.60
4.79
1.24
0.169
1.56
0.0138
1 84
. 0.00384
0
0
189
ZE-AH-003
Value
10
120
176
1,136
35
248
52
43
448
11
11
22
"104
95
134
45
20
280
122
0
155
ID
44
294
59
- -- --
Toxicity
Equivalents
10
1.2
17.6
1.14
17.5
1.24
5.2
4.3
0.448
0.44
0.44
0.88
0.042
0.95
1.34
0.45
0.20
0.028
0.122
0
, 0.155
0.016
0.00044
0
0 '
63.7
do
O) Toxicity Equivalency factors are EPA's current recommended Factors, (EPA, March 1987).
ND Not detected below 221 pg/g.
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sodium (results for Facilities ZD and ZE are lower than the results for the other
facilities); calcium oxide (the results for Facilities ZA and ZB are higher than the
results for the other facilities); and silicon dioxide (the results for Facility ZC are
higher than the results for the other facilities).
Some additional findings of the ash sampling and analyses are as follows:
« The ashes are alkaline with the pH ranging from 10.36 to 11.85.
The ashes are rich in chlorides and sulfates. The total soJuble solids in the
ashes varied from 6,440 to 65,800 ppm.
The ashes contained unburnt total organic carbon (TOC) ranging from
4,060 ppm (0.4 percent) to 53,200 ppm (5.32 percent).
The major findings of the leachate sampling and analysis during this study are
summarized in the following paragraphs.
Only four Appendix IX semivolatile compounds were found in the ieachates from the
ash disposal facilities. Benzoic acid was found in both leachate samples collected at
one of the five ash disposal facilities. Phenol, 3-methylphenol, and 4-methylphenol
were found in some of the leachate samples from one of the other facilities. All of
these compounds were detected at very low levels (2-73 ppb).
PCDDs/PCDFs were only found in the leachate from one facility. The homologs
found are the more highly chlorinated homologs. The data obtained during this
study appears to indicate that PCDDs/PCDFs do not readily leach out of the ash in the
ash disposal facilities. The low levels found in the Ieachates of the one facility
probably originated from the solids found within the leachate samples because
these samples were not filtered nor centrifuged prior to analysis.
None of the leachate samples exceeded the EP Toxicity Maximum Allowable Limits
established for the eight metals in Section 261.24 of 40 CFR 261. In addition, the
data from this study indicate that although the Ieachates are not used for drinking
purposes, they are close to being acceptable for drinking water use, as far as the
metals are concerned.
R339911 ES-9
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Some other findings of the leachate sampling and analyses are as follows:
Sulfate values ranged from 14.4 mg/L to 5,080 mg/L, while Total Dissolved
Solids (TDS) ranged from 924 mg/L to 41,000 mg/L.
The field pH values ranged from 5.2 to 7.4.
Ammonia (4.18-77.4 mg/L) and nitrate (0.01-0.45 mg/L) were present in
almost all leachate samples.
Total Organic Carbon values ranged from 10.6 to 420 ppm.
The major findings from the analysis of the ash extracts during this study are
summarized as follows:
Of the five composite samples of the deionized water (SW-924) extracts
analyzed for the Appendix IX semivolatile compounds (one from each
facility), only one sample contained low levels of benzoic acid (0.130 ppm).
None of the extracts contained PCDDs/PCDFs. These data confirm the
findings of the actual field leachate samples that PCDDs/PCDFs are not
readily leached from the ash.
The data obtained during the metals analyses of the ash extracts indicate that, in
general, the extracts from the EP Toxicity, the TCLP1, and the TCLP2 extraction
procedures have higher metals content than the extracts from the deionized water
(SW-924), the CO2, and the Simulated Acid Rain (SAR) extraction procedures. The EP
Toxicity Maximum Allowable Limits for lead and cadmium were frequently exceeded
by the extracts from the EP Toxicity, TCLP 1, and TCLP 2 extraction procedures. One
of the extracts from the EP Toxicity extraction procedure also exceeded the EP
Toxicity Maximum Allowable Limit for mercury.
None of the extracts from the deionized water (SW-924), the CO2, and the Simulated
Acid Rain (SAR) extraction procedures exceeded the EP Toxicity Maximum Allowable
Limits. In addition, the majority of the extracts from these three extraction
procedures also met the Primary and Secondary Drinking Water Standards for
metals
R339911 ES-10
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Table ES-4 compares the range of concentrations of the metals analyses of the ash
extracts with the range of concentrations for leach-ate as reported in the literature
(EPA, October 1987). and the range of concentrations for the leachates as
determined in this study. For the facilities sampled during this study, the data in
Table ES-4 indicate that the extracts from the deionized water (SW-924), the CC>2,
and the SAR extraction procedures simulated the concentrations for lead and
cadmium in the field leachates better than the extracts from the other three
extraction procedures.
R339911 ES-11
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30
UJ
TABLE ES-4
COMPARISON OF ASH EXTRACT METAL ANALYSES RESULTS
WITH LEACHATE METAL ANALYSES RESULTS
Parameter
Arsenic
Barium
Cadmium
Chromium
Copper
Iron
Lead
Manganese
Mercury
Selenium
Silver
Sodium
Zinc
EPTOX
Extracts
23-455
25-1,200
ND-86
24-5,170
ND-82,000
ND- 19,700
250-8,540
ND-203
ND
ND
33,600-
225,000
67-95,600
TCLP1
Extracts
ND
161-1,850
ND-1,150
ND-8.0
5-858
ND-7,220
ND-1 0,500
ND-5,170
ND-3.8
ND
ND
1.380,000-
1,640,000
9.7-79,500
Samples (ng/L)
TCLP2
Extracts
ND-60
12-809
ND-1, 560
ND-799
5.4-1,400
ND-1 62,000
ND-26,400
3.8-7,370
ND-4.6
ND
ND
38,700-
228,000
26-164,000
CO2 Extracts
ND-53
126-530
ND-354
ND-9.8
8.8-620
ND-304
ND-504
ND-2,390
ND-1 55
ND
ND-1 6
24,800-
168,000
5-127,000
DIH2O
Extracts
ND-45
139-3,050
ND-7.6
ND-1 6
12-534
ND-115
ND-3,410
ND-20
ND-0.96
ND
ND
24,100-
209,000
5.4-1,340
SAR Extracts
ND
129-3,960
ND-6.0
ND-10
8.5-610
ND-97
ND-3,940
ND-6.4
ND-1.1
ND-23
ND
24,200-
201,000
12-1,290
Leachate
(Literature)O)
5-218
1,000
ND-44
6-1,530
22-24,000
168-
121,000
12-2,920
103-4,570
1-8
2.5-37
70
200,000-
4,000,000
ND-3,300
Leachate
(CORRE)
ND-400
ND-9,220
ND-4
ND-32
ND-1 2
108-10,500
ND-54
310-18,500
ND
ND-340
ND
188,000-
3,800,000
5.2-370
m
NJ
-------
s
UJ
10
TABLE ES-4
COMPARISON OF ASH EXTRACT METAL ANALYSES RESULTS
WITH LEACHATE METAL ANALYSES RESULTS
PAGE TWO
Parameter
Aluminum Oxide*
Calcium Oxide*
Magnesium Oxide*
Potassium
Monoxide*
Silicon Dioxide*
Samples (pg/L)
EPTOX
Extracts
ND-1 50.000
592,000-
4,810.000
27,300-
130;000
10,100-
189,000
5,090-98,700
TCLP1
Extracts
ND-62,800
666,000-
2,750,000
55-375,000
14,600-
210,000
379-51,700
TCLP2
Extracts
ND-1 52,000
692,000-
3,640,000
623-137,000
15,100-
1,110,00
820-143,000
COj Extracts
ND-90,700
398,000-
1,920,000
207-59,300
12,300-
155,000
418-71,800
DIH2O
Extracts
ND-203,000
. 141,000-
1,740,000
21-379
13,100-
189,000
402-3,990
SAR Extracts
ND-1 18,000
142,000-
1,800,000
12-430
14,500-
181,000
364-3,770
Leachate
(Literature)C)
NR
21,000
NR
21,500
NR
Leachate
(CORRE)
ND-920
64,600-
8,390,000
14,800-
367,000
79,700-
1,620,000
470-15,300
m
i/>
ND Not Detected. .
NR Not Reported in the literature.
<» EPA, October 1987.
* The ash extracts were analyzed as ions for these compounds and reported as oxides. The leachates were analyzed and are reported as ions for
these compounds.
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