United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-01/055 January 2002
Project Summary
Field Demonstration of
Lead-Based Paint Removal and
Inorganic Stabilization
Technologies
John R. Kominsky
A study was conducted to demon-
strate the effectiveness of a wet abra-
sive blasting technology to remove
lead-based paint from exterior wood sid-
ing and brick substrates, and the effec-
tiveness of two Best Demonstrated
Available Technologies (BOAT) to sta-
bilize the resultant blasting media (coal
slag and mineral sand) paint debris to
reduce the leachable lead content. The
average lead loading of the paint coat-
ing on the wood and brick substrates
was 6.9 and 51.9 mg/cm2, respectively.
The effectiveness of the lead-based
paint removal technology was deter-
mined using an X-ray fluorescence
(XRF) spectrum analyzer (L&K shell).
The XRF measurements were corrobo-
rated by analysis of substrate samples
using inductively-coupled plasma
atomic emission spectroscopy (ICP-
AES). The effectiveness of the tech-
nologies to stabilize the debris was
evaluated through the Toxicity Charac-
teristic Leaching Procedure (TCLP).
Aerodynamic particle size distributions
of lead particulate generated during
paint removal were measured using a
multi-stage personal cascade impactor.
Personal and area air samples were
collected to evaluate the potential of
the wet abrasive blasting technology to
generate exposure levels of lead above
the OSHA Permissible Exposure Limit
(PEL) of 50 ug/m3, 8 hour time-weighted
average.
Wet abrasive blasting effectively re-
moved the lead-based paint coating
from both the wood and brick substrates
to below the U.S. Department of Hous-
ing and Urban Development Guideline
(1 mg/cm2) with minimal or no damage
to the underlying substrates (p<0.0001).
The mean area air levels of lead-con-
taining particulate generated during
paint removal were significantly below
the PEL (p<0.001), whereas the mean
personal breathing zone lead levels
were approximately three times higher
than the PEL. Neither of the two stabili-
zation technologies consistently stabi-
lized the abrasive media paint debris to
achieve a leachable lead content below
the RCRA regulatory threshold (< 5 mg/
L).
This project Summary was developed
by EPA's National Risk Management
Research Laboratory, Cincinnati, OH, to
announce key findings of the research
project that is fully documented in a sepa-
rate report of the same title (see Project
Report ordering information at back).
Introduction
The Lead-Based Paint Poisoning Pre-
vention Act of 1971, as amended by the
Housing and Community Development
Act of 1987, established 1.0 milligram of
lead per square centimeter of surface area
(mg/cm2) as the federal threshold requir-
ing abatement of lead-based paint on ar-
chitectural components in public and
Indian housing developments nationwide.
The Residential Lead-Based Paint Haz-
ard Reduction Act of 1992 (commonly
referred to as "Title X") mandated the
evaluation and reduction of lead-based
paint hazards in the nation's existing
housing. Title X also established 0.5 per-
cent lead by weight as an alternative to
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the 1.0 mg/cm2 threshold. An U.S. Envi-
ronmental Protection Agency (EPA) study1
found that a level of 1.0 mg/cm2 was
roughly equivalent to 1.0 percent by
weight and a level of 0.5 percent by
weight was roughly equivalent to 0.5 mg/
cm2.
The management of wastes generated
from lead-based paint abatement activi-
ties are governed by the Resource Con-
servation and Recovery Act (RCRA) of
1976 and provisions contained in 40 CFR
Parts 260-268. RCRA classifies any waste
that leaches 5 milligrams per liter (mg/L)
of lead or more (as determined by a Tox-
icity Characteristic Leaching Procedure2)
a hazardous waste. The leachability of
lead is affected by various factors, includ-
ing speciation of the metal, pH of the
leachate, particle size, acid flux through
the waste, and time of contact with the
leachant. The U.S. Environmental Protec-
tion Agency (EPA) has promulgated a list
of Best Demonstrated Available Technolo-
gies (BOAT) for the inorganic stabiliza-
tion of hazardous wastes including
lead-containing wastes. Stabilization in-
cludes those techniques that limit the solu-
bility of hazardous constituents in the
waste.3 Much of the inorganic stabiliza-
tion that occurs in the United States is
based on the chemistry of lime or ordi-
nary Portland cement.
Objective
The overall objective of this study was
to demonstrate the effectiveness of a wet
abrasive blasting technology combined
with an inorganic-based stabilization tech-
nology to remove lead-based paint from
exterior substrates (wood and brick) and
to generate a non-hazardous waste for
disposal.
Study Design
This study evaluated the effectiveness
of a wet abrasive blasting technology
(Torbo®) combined with two inorganic-
based stabilization technologies (Blastox®
and PreTox 2000 Fast Dry) to remove
lead-based paint from exterior substrates
(brick and wood) and to generate a non-
hazardous waste for disposal. Each tech-
nology combination (e.g., Torbo® with
PreTox 2000 Fast Dry) was demonstrated
on the two substrates (brick and wood) to
yield two treatments. Each treatment was
replicated three times to yield six experi-
ments per technology combination.
Brick- A single building wall (approxi-
mately 28' H x 157' L) was used as the
exterior painted brick substrate. The lead
loading on the brick ranged from 1.5 to
15.2 mg/cm2 (average 6.9 mg/cm2, std.
dev. 3.2 mg/cm2) using a NITON Model
703-A X-ray fluorescence (XRF) spectrum
analyzer (K & L Shell Combined). The
masonry wall was divided into six areas
that ranged from 556 to 756 ft2 (average
627 ft2). The differences in surface area
are due to the presence of varying num-
bers of windows on the wall; the respec-
tive areas were subtracted from each of
the test areas. Each technology combina-
tion was assigned at random to the six
test areas.
Wood — Five buildings with 4-inch pop-
lar wood siding were used as the exterior
painted wood substrate. The buildings
were located on the same property, had
an identical architectural design, and re-
portedly had similar painting histories. The
lead loading on the wood siding ranged
from 13.1 to 51.9 mg/cm2 (average 33.3
mg/cm2, std. dev. = 10.1 mg/cm2) using a
NITON Model 703-A XRF spectrum ana-
lyzer (K & L Shell Combined). Two test
areas were selected from one building
and one test area was selected from each
of the remaining four buildings, yielding a
total of six test areas. The six test areas
ranged from 294 to 431 ft2 (average 363
ft2). The technology combinations were
randomly assigned to the test areas.
Technologies Evaluated
Torbo0 Wet Abrasive Blasting
System
The Torbo® Wet Abrasive System is
manufactured by Keizer Technologies of
Americas, Inc. in Euless, Texas. The sys-
tem uses conventional blasting abrasives
mixed with water (80% abrasive to 20%
water) in a pressure vessel. During this
study, mineral slag was used to remove
the paint from the brick and coal slag
(Black Beauty®) was used to remove the
paint from the wood.
The system combines the abrasive
media and water to create a slurry-mix-
ture that is fed to a blast nozzle much like
a conventional blasting system. In con-
cept, each particle of the abrasive is en-
cased in a thin layer of water. It utilizes
this coating to both reduce the heat gen-
erated by friction and form a cohesive
bond for the dust created by the blasting
process that reduces the fugitive particu-
late emissions.
Blastox®
Blastox® is manufactured by TDJ Group
Inc. in Gary, Illinois. Blastox®, an abrasive
additive, is a di- and tri-calcium silicate-
based material similar in chemical com-
position to Type I cement. Typically, for
lead-based paint removal, it is added at a
20-25 weight percent ratio to the non-
recyclable blasting media such as min-
eral sand or coal slag. For this study, the
supplier of the abrasive reportedly
premixed the Blastox® additive at a 20
and 15 percent weight ratio to the abra-
sive (mineral sand or coal slag) for paint
removal from the wood and brick sub-
strates, respectively.
A U.S. Army Corps of Engineers study4
concluded that Blastox® stabilizes lead-
containing paint blast media wastes (i.e.,
reduces the leachability of lead) by a se-
ries of simultaneous reactions that result
in an encapsulated lead silicate com-
pound, which is insoluble at all pH levels.
The first reaction is a pH adjustment that
simultaneously stabilizes the lead by ad-
justing the pH range (8.0-11.5) where
there is limited leachability for lead. Sec-
ondly, the chemical form of the lead is
changed from a lead oxide, carbonate, or
hydroxide, to a lead silicate, which is in-
soluble. A U.S. EPA study5 concluded that
Blastox® appears to stabilize the lead
through an immobilization mechanism,
rather than by chemical reaction of lead
oxide, to form a lead silicate. Lastly, hy-
dration reactions encapsulate the waste
into a cementitious material, which limits
the gravitational flow of water through the
waste.
PreTox 2000 Fast Dry
PreTox 2000 Fast Dry (hereafter re-
ferred to as PreTox 2000) is manufac-
tured by NexTec, Inc. in Dubuque, Iowa.
PreTox 2000 is a cementitious paint-like
mixture (i.e., treatment layer) designed to
be applied to lead-based paint surfaces
and allowed to cure and adhere to the
paint coating; it then is removed in con-
junction with the underlying lead-based
paint coating using abrasive blasting or
other standard techniques. PreTox 2000
is composed of materials from the com-
pounds of sodium and potassium silicates,
sodium and potassium phosphate, and
calcium silicate, iron and aluminum sul-
fates, and an alkali metal salt.6 It also
contains toluene, acetone, and VM&P
naptha as carrier solvents. Typically,
PreTox 2000 is designed to be applied to
a 10- to 60-mil (wet) thickness depending
on substrate and paint condition; the av-
erage application is 40-mil (wet) thick-
ness. For this study, the manufacturer's
representative used an airless sprayer to
apply PreTox 2000 to a surface of 40 mil
(wet) thickness.
The manufacturer reports that the
PreTox 2000 system stabilizes the lead
through two mechanisms. The first mecha-
nism is chemical stabilization through pH
adjustment, which instantaneously stabi-
lizes the lead by adjusting the pH range
(8.0-11.5) where there is limited leach-
ability for lead. The second is chemical
-------
fixation that changes the soluble ionic
form of lead to an insoluble metallic form.
Test data provided by NexTec, Inc.
showed that PreTox 2000 successfully
stabilized lead-based paint debris, yield-
ing a leachable lead content of <5 mg/L
using both the TCLP and Multiple Extrac-
tion Procedure (MEP).
Sampling and Analytical
Methods
Thickness of Dry Paint Film
The measurement of dry film thickness
of the paint was made using ASTM
Method D 4138-88.
Lead in Dry Paint Film
Lead in paint measurements (XRF and
ICP-AES) were made before paint re-
moval to establish the lead loading on
the test panel. The measurements were
made at approximately the same five lo-
cations as the paint film thickness mea-
surements. The measurements were
made in accordance with Chapter 7
"Lead-Based Paint Inspection" (1997 Re-
vision) of the HUD Guidelines.
XRF Measurements
A NITON XRF Spectrum Analyzer
(Model 703-A) running software Version
5.1 was used to determine the lead load-
ing on the brick and wood substrates.
The instrument was operated in the vari-
able-time paint test mode "K & L + Spec-
tra" using the "Combined Lead Reading?
with the instrument display of a 95% con-
fident (2-sigma) positive or negative de-
termination versus the threshold-level (1
mg/cm2) as the stopping point of the mea-
surement. There is no inconclusive clas-
sification when using the threshold for
this instrument running software version
5.1.11 Results are classified as positive
(i.e., > 1.0 mg/cm2), if greater than or equal
to the threshold, or negative (i.e., < 1.0
mg/cm2) if less than the threshold. The
instrument reads until a 95% confident
reading of "Positive" or "Negative" versus
the threshold (1 mg/cm2) is achieved.
Paint Chip Sampling
A paint chip sample for ICP-AES analy-
sis was obtained at approximately the
same location as three of the five XRF
measurements. Each sample was ob-
tained from a 1Vi-inch by 1%-inch (ap-
proximately 3.17-cm by 3.17-cm) square
area. The samples were prepared for
analysis in accordance with EPA SW-846
Method 3050 and analyzed by ICP-AES
in accordance with EPA SW-846 Method
6010. The analytical limit of detection was
reported as 5 ug/sample.
Lead on Bare Substrate
Lead on bare substrate measurements
(XRF and ICP-AES) were made after paint
removal to establish the residual lead load-
ing in the test area. The six wood siding
test areas and the six brick wall test ar-
eas were each equally dimensioned into
25 areas (i.e., grid squares). The mea-
surements were made at the approximate
center point of each grid square. An XRF
measurement was made in each of the
25 grid squares. A bare substrate sample
for ICP-AES analysis was collected from
five of the 25 squares; the test locations
were randomly selected.
Lead in Airborne Particulate
Personal Breathing Zone Samples
Personal breathing zone and work area
air samples were collected during each
technology demonstration. The samples
were collected and prepared for analysis
by ICP-AES in accordance with NIOSH
Method 7300.
Lead Particulate Aerodynamic
Particle Size Distribution
An 8-stage Marple Personal Cascade
Impactor (Model 298) was used to deter-
mine the aerodynamic particle size distri-
bution of the lead particulate generated
during each technology demonstration.
The samples were collected and prepared
for analysis by ICP-AES in accordance
with NIOSH Method 7300.
Characterization of Abrasive
Media Paint Debris
Representative samples of the abra-
sive media paint debris (spent abrasive,
stabilization product, paint chips/particles)
were collected to determine whether the
material generated from a technology
combination was a RCRA (40 CFR Part
261) hazardous waste based on the Tox-
icity Characteristic Leaching Procedure
(TCLP). The samples were extracted in
accordance with EPA SW-846 Method
1311, digested in accordance with EPA
SW-846 Method 3015, and analyzed in
accordance with EPA SW-846 Method
6010.
Statistical Methods
All comparisons of two sample means
were made using a standard two-sample
t-test. If the distributional assumption of
normality was not reasonable, then the
corresponding nonparametric distribution-
free method was used (i.e., Wilcoxon
Rank Sum Test). All one-sample com-
parisons to a regulatory action level (1
mg/cm2) were made using a standard one-
tailed t-test. Again, if the distributional as-
sumption of normality was not reason-
able, then the corresponding nonpara-
metric method was used (i.e., Signed
Rank Test). All of these statistical com-
parisons were made at the 0.05 level of
significance. The upper limit of the 80
percent confidence interval for the mean
concentration of leachable lead in the
abrasive media paint debris was calcu-
lated to determine if the material was a
RCRA hazardous waste.7 If the mean
concentration of leachable lead plus the
80 percent confidence interval is greater
than the regulatory threshold (5 mg/L),
the material was considered to be a haz-
ardous waste.
Results and Discussion
Effectiveness of Paint Removal
XRF Measurements Before and
After Paint Removal
Tables 1 and 2 present descriptive sta-
tistics for the XRF measurements obtained
before and after paint removal on wood
and brick substrates, respectively, for
each technology combination. A one-tailed
t-test was used to determine whether the
mean lead concentration after paint re-
moval was significantly less than 1 mg/
cm2 both by substrate (i.e., wood and
brick) and overall for each technology
combination. In every case, both by sub-
strate and overall, the results show that
both Torbo®-Blastox® and Torbo®-PreTox
2000 reduced lead concentrations on
wood and brick to a level significantly
below 1 mg/cm2.
Comparison of XRF
Measurements and ICP-AES
Analysis
Tables 3 and 4 present descriptive sta-
tistics for the XRF measurements obtained
before and after paint removal on wood
and brick substrates, respectively, for
each technology combination. The
Wlcoxon Rank Sum Test was used to
compare lead concentrations measured
by XRF and ICP-AES on the wood and
brick substrates both before and after
paint removal. The lead concentrations
determined by ICP-AES and XRF mea-
surements before paint removal on wood
were not significantly different (p=0.1055);
however, the measurements before paint
removal on brick were significantly differ-
ent (p=0.0001). The lead concentrations
determined by ICP-AES and XRF mea-
surements after paint removal on wood
were significantly different (p=0.0331);
however, the measurements after paint
removal on brick were not significantly
different (p=0.5504).
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Table 1. Descriptive Statistics for XRF Measurements (K & L Shell Combined)
Collected Before and After Paint Removal on Exterior Wood Siding
Technology
Combination
Lead Concentration (mg/cmi2)
N
Mean
Std. Dev.
Minimum
Maximum
Before Paint Removal
Torbo®with Blastox®
Torbo®with PreTox 2000
15
15
36.9
29.7
9.52
9.66
15.5
13.1
51.9
41.4
After Paint Removal
Torbo®with Blastox®
Torbo®with PreTox 2000
75
75
0.24
0.16
0.22
0.16
0
0
1.1
0.70
Table 2. Descriptive Statistics for XRF Measurements (K & L Shell Combined)
Collected Before and After Paint Removal on Exterior Brick
Technology
Combination
Lead Concentration (nig/cmi2)
N
Mean
Std. Dev.
Minimum
Maximum
Before Paint Removal
Torbo®with Blastox®
Torbo®with PreTox 2000
15
15
5.59
8.18
1.78
3.71
1.5
3.9
9.7
15.2
After Paint Removal
Torbo®with Blastox®
Torbo®with PreTox 2000
75
75
0.14
0.11
0.09
0.14
0
0
0.4
1.1
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Table 3. Lead Concentrations in Paint and on Wood Measured by ICP-AES and
XRF (K & L Shell Combined)
Method of
Measurement
Lead Concentration (mg/cm2)
N
Mean
Std. Dev.
Minimum
Maximum
Before Paint Removal
ICP-AES
XRF (L& K Shell)
18
30
28.2
33.3
12.8
10.1
9.1
13.1
51.6
51.9
After Paint Removal
ICP-AES
XRF (L& K Shell)
30
150
0.37
0.20
0.50
0.20
0.01
0
2.68
1.10
Table 4. Lead Concentrations in Paint and on Brick Measured by ICP-AES and
XRF (K & L Shell Combined)
Method of
Measurement
Lead Concentration (mg/cm2)
N
Mean
Std. Dev.
Minimum
Maximum
Before Paint Removal
ICP-AES
XRF (L&K Shell)
18
30
2.93
6.89
2.11
3.15
0.20
1.5
9.1
15.2
After Paint Removal
ICP-AES
XRF (L&K Shell)
30
150
0.20
0.13
0.30
0.12
0.005
0
1.39
1.10
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Characterization of Abrasive
Media Paint Debris
Coal Slag Paint Debris from
Wood Substrate
Table 5 presents the mean leachable
lead levels and corresponding upper con-
fidence limits for the abrasive paint de-
bris by site and overall for both technology
combinations. Overall, the abrasive paint
debris from both technology combinations
was determined to be a hazardous waste.
If examined on a site-by-site basis, the
debris is also determined to be a hazard-
ous waste. The mean leachable lead lev-
els in abrasive media debris generated
from the removal of paint from wood by
the two technology combinations were
compared by using a standard two-sample
t-test. The mean leachable lead level in
the debris generated from the Torbo®-
Blastox® combination (21.3 mg/L) was not
significantly different (p=0.4459) from the
mean leachable lead level in the debris
generated from the Torbo®-PreTox 2000
combination (14.8 mg/L).
Mineral Sand Paint Debris from
Brick Substrate
Table 6 presents the mean leachable
lead levels and corresponding upper con-
fidence limits for the abrasive paint de-
bris by site and overall for both technology
combinations. Overall, the abrasive paint
debris from both technology combinations
was determined to be a hazardous waste.
If examined on a site-by-site basis, the
debris is also determined to be a hazard-
ous waste, with one exception. The two
samples collected from debris at Site 1
(Torbo®-Blastox®) showed an 80% UCL
of 3.9, which by itself would not be classi-
fied as a hazardous waste. The mean
leachable lead levels in abrasive media
debris generated from the removal of
paint from brick by the two technology
combinations were compared by using a
standard two-sample t-test. The mean
leachable lead level in the debris gener-
ated from the Torbo®-Blastox® combina-
tion (8.1 mg/L) was not significantly
different (p=0.9555) from the mean leach-
able lead level in the debris generated
from the Torbo®-PreTox 2000 combina-
tion (7.8 mg/L).
Overall, the abrasive media paint de-
bris characterization results (Tables 5-6)
are somewhat surprising. The leachablility
of lead is affected by many factors includ-
ing, type of lead in paint, resins used in
the paint, age of the paint, particle size,
and others.8'9 The manufacturers of the
stabilization technologies postulate that
the ineffectiveness of their respective
products in this study was due to insuffi-
cient product added or applied to stabi-
lize the concentration of lead present in
the paint. The reason(s) why these stabi-
lization technologies were ineffective un-
der the conditions of this study is
equivocal.
Blastox®—The material supplier pro-
vided a 20% and 15% blend ratio of
Blastox® with the coal slag and mineral
sand abrasives for use on the wood and
brick substrates, respectively. A 30% and
20% blend ratio of Blastox® with the re-
spective abrasives would have been pre-
ferred by the manufacturer. Hence, the
optimum blend ratio was not used in the
demonstration. Mis-communication be-
tween the manufacturer and the abrasive
supplier resulted in the incorrect blend-
ing ratio of Blastox® with the abrasive.
Subsequently, the manufacturer issued a
technical bulletin to minimize the prob-
ability of this blending error occurring in
the future.12
PreTox 2000—The manufacturer of
PreTox 2000 recommends a 10-40 mil
(wet) thickness application; a 40 mil (wet)
thickness was applied to both the wood
and brick substrates. A 60 mil (wet) thick-
ness application for the wood substrates
would have been preferred by the manu-
facturer. Hence, the optimum application
mil thickness was not used in the demon-
stration.
Air Measurements
Personal and Area Air
Measurements
In all cases, the mean airborne lead
levels measured by the personal breath-
ing zone samples were significantly
greater than the 50 ug/m3 8-hour TWA
(Table 7).
Lead Particulate Aerodynamic
Particle Size Distribution
Figure 1 shows the average differential
lead particle size distribution for the two
samples. This graph provides the particle
mass concentration ( C) in each particle-
size band versus the geometric mean di-
ameter (GMDj), where GMDt = D: x DM.
The lead particles generated by the wet
abrasive blasting of the surface coating
covers a wide-size spectrum, where the
larger particles account for the greatest
mass of lead. The corresponding cumu-
lative particle size distribution was deter-
mined by preparing a log-probability plot
of the particle size cut-point (Dp) versus
the cumulative percent of mass (mg/m3)
less than the Dp. The distribution of
sample weights appeared to approximate
a lognormal distribution with a mass me-
dian diameter (MMD) of 8.3 urn. That is,
50% of the particle mass is borne by
particles larger than 50 urn. The calcu-
lated geometric standard deviation (GSD)
was 3.4. By comparison, a GSD of 1 rep-
resents a monodisperse aerosol.
Cost Analysis
A cost analysis of the Torbo®-Blastox®
and Torbo®-PreTox 2000 technology
combinations to remove lead-based paint
from wood and brick substrates is pre-
sented in the Project Report.
Conclusions
•_ Wet abrasive blasting effectively
removed the lead-based paint from
both exterior wood siding and brick
masonry with minimal damage to
the underlying substrates (only light
sanding of the wood was required
prior to painting or tuck pointing of
the mortar joints). The residual lead
levels were significantly below the
HUD Guideline of 1 mg/cm2
(p<0.0001). The average paint re-
moval rates were 76.4 and 119.8
ft2/hr on wood and brick, respec-
tively.
•_ The lead concentrations deter-
mined by ICP-AES analysis and
determined by XRF measurements
before paint removal on wood were
not significantly different
(p=0.1055); however, these deter-
minations before paint removal on
brick were significantly different
(p=0.0001). The lead concentra-
tions determined by ICP-AES
analysis and determined by XRF
measurements after paint removal
on wood were significantly differ-
ent (p=0.0331); however, these
determinations after paint removal
on brick were not significantly dif-
ferent (p=0.5504).
•_ The wet abrasive slurry-mixture
appears to reduce the fugitive emis-
sions of lead-containing particulate,
which serves to enhance the level
of environmental protection as well
as worker health and safety. The
mean area air levels of lead-con-
taining particulate generated dur-
ing paint removal were significantly
below the OSHA PEL of 50 ug/m3
(p<0.001), whereas the mean per-
sonal breathing zone levels of lead
were approximately three times
higher than the PEL. The personal
breathing zone levels of lead did
not vary significantly with substrate
(p=0.6396); the area samples
showed higher levels of lead dur-
ing removal of paint from brick than
6
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Table 5. Characterization of Coal Slag Paint Debris from Wood Substrates
Technology
Combination
Torbo®-Blastox®
Torbo®-PreTox
2000
Substrate
Wood
Wood
Site
1
2
5
Overall
3
4
6
Overall
N
2
2
2
6
3
3
3
9
Leachable Lead Level
Mean (mg/L)
12.4
15.5
36.0
21.3
7.7
29.7
7.1
14.8
80% UCL for Mean
39.0
47.9
85.2
31.9
20.2
39.2
17.5
21.4
Table 6. Characterization of Mineral Sand Paint Debris from Brick Substrates
Technology
Combination
Torbo^-Blastox®
Torbo®-PreTox
2000
Substrate
Brick
Brick
Site
2
4
6
Overall
1
3
5
Overall
N
2
2
2
6
2
2
2
6
Leachable Lead Level
Mean (mg/L)
1.1
19.5
3.6
8.1
9.4
5.9
8.3
7.8
80% UCL for Mean
3.9
21.0
9.6
13.5
11.4
11.9
9.5
9.1
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Table 7. Comparisons of Personal and Area Air Concentrations to OSHA PEL
Technology
Combination
Torbo® with
Blastox®
Torbo®with
PreTox 2000
Substrate
Wood
Brick
Wood
Brick
Type of
Sample
Personal
Area
Personal
Area
Personal
Area
Personal
Area
N
3
9
6
18
3
12
6
16
Mean 8-hr TWA
(Mg/m3)
70.9
20.5
68.4
21.2
55.1
26.9
81.5
24.9
t statistic
0.8958
-6.40
1.03
-3.36
0.3163
-6.53
5.63
-3.60
p-value
0.7675
0.0001
0.8257
0.0018
0.6091
0.0001
0.9975
0.0013
8
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for paint removal from wood
(p=0.0463).
• _ Neither of the two stabilization tech-
nologies (Blastox® and PreTox
2000) consistently stabilized the
abrasive media lead-based paint
waste to reduce the leachable lead
content. The 80 percent upper
confidence interval for the mean
leachable lead concentration in the
debris consistently exceeded the
RCRA regulatory threshold (5 mg/
L). Failure of the technologies to
stabilize the lead most likely was
due to an inadequate chemical
stabilizer-abrasive blend ratio or
insufficient application mil thickness
of the pre-paint removal coating
treatment in the case of Blastox®
and PreTox 2000, respectively.
Recommendations
•_ Although wet abrasive blasting re-
duces fugitive emissions of lead-
containing particulate generated
during removal of paint film from
exterior wood or brick masonry, it
should be conducted in at least a
Class 4 Containment System as
specified in SSPC Guide 6, "Guide
for Containing Debris Generated
During Paint Removal Operations."
Air monitoring should be conducted
at the perimeter work area to de-
termine the extent that lead-con-
taining particulate are escaping
from the work area.
•_ To maximize the performance of
these technologies the user should
understand the various factors that
may affect the effectiveness of the
product to reduce the leachable
lead content of the debris. Included
are paint film lead content, paint
film thickness, paint film condition,
type of substrate (e.g., wood, brick,
metal), variant particle size, and
other potentially significant factors.
PreTox 2000-The user of this tech-
nology should follow the applica-
tion optimization procedure
specified in the technical guidance
provided by the manufacturer. This
will ensure that the optimum mil
thickness application rate of
PreTox 2000 is applied to the lead-
based paint coating to be abated.
S/asfox®-Subsequent to complet-
ing this study, the manufacturer of
Blastox® revised their technical
guidance regarding the proper
blend ratios of abrasive to chemi-
cal-stabilizer. The user of this tech-
nology should verify that the blend
ratio provided by the material sup-
plier is consistent with the recom-
mended blend ratio for a given
lead-based paint coating to be
abated.
•_ Due to the inability of these tech-
nologies to consistently reduce the
leachable lead content in the abra-
sive media paint debris during this
demonstration, all debris should be
tested by TCLP prior to disposal.
The sampling strategy should be
consistent with Chapter 9 "Sam-
pling Plan" of SW-846 " Test Meth-
ods of Environmental Testing of
Solid Wastes."
References
1. U.S. Environmental Protection
Agency, Office of Pollution Preven-
tion and Toxics. A Field Test of Lead-
Based Paint Testing Technologies:
Technical Report, EPA 747-R-95-
002b. May 1995.
2. U.S. Environmental Protection
Agency, Office of Pollution Preven-
tion and Toxics. Toxicity Character-
istic Leaching Procedure, Method
1311. Test Methods of Environmen-
tal Testing Solid Wastes - Physical
and Chemical Methods, SW-846 (3rd
ed.). November 1986.
3. U.S. Environmental Protection
Agency, Office of Pollution Preven-
tion and Toxics. Stabilization/Solidi-
fication of CERLA and RCRA Wastes.
EPA/625/6-89/022. May 1989.
4. Hock, V., C. Gustafson, D. Cropek,
and S. Drozdz. U.S. Army Corps of
Engineers, Construction Engineering
Research Laboratories. Demonstra-
tion of Lead-Based Paint Removal
and Chemical Stabilizer Using
Blastox. Technical Report FEAP-TR-
96/20. October 1996.
5. U.S. Environmental Protection
Agency, Office of Pollution Preven-
tion and Toxics. Stabilization of Lead-
Based Paint Waste. October 1998
(Draft).
6. U.S. Patent Number 5,674,108.
Method for Removing Coatings Which
Create Hazardous Products. Octo-
ber 7, 1997.
7. U.S. Environmental Protection
Agency, Office of Pollution Preven-
tion and Toxics. Chapter Nine Sam-
pling Plan. Test Methods of
Environmental Testing Solid Wastes
- Physical and Chemical Methods,
SW-846 (3rd ed.). November 1986.
8. Bishop, P. L. 1988. Leaching of inor-
ganic hazardous constituents from
stabilized/solidified hazardous
wastes. Hazardous Waste & Haz-
ardous Materials 5(2): 129-143.
9._ Buskowski, J. M., J. H. Boy, X. Zhu, T.
D. Race, and K. A. Reinhold. Immo-
bilization chemistry in Portland ce-
ment stabilized paint blast media
wastes. Environmental and Waste
Management Issues in the Ceramic
Industry II 45: 155-163. 1994.
10. Technical Bulletin: Determining
Proper Blastox® Blend Ratios. TB-
007 (Issued 10-98), The TDJ Group
Inc., Gary, Illinois 60013.
The full report was submitted in partial
fulfillment of Contract No. DACW88-97-
D-0017 by Environmental Quality Man-
agement, Inc. This work was conducted
under sponsorship of the U.S. Environ-
mental Protection Agency and the U.S.
Army Construction Engineering Research
Laboratories (USACERL).
This Project Summary was written by
John R. Kominsky of Environmental Qual-
ity Management, Inc., Cincinnati, OH
45240.
Alva Edwards-Daniels is the EPA
Project Officer and can be contacted at:
National Risk Management Research-
Laboratory _
U.S. Environmental Protection Agency_
26 W. Martin Luther King Drive_
Cincinnati, OH 45268_
Telephone: 513 569-7693_
The complete report, entitled "Field
Demonstration of Lead-Based Paint Re-
moval and Inorganic Stabilization Tech-
nologies," can be located on the Internet
at:
www.epa.gov/ORD/NRMRL/Pubs/
600R01055/600R01055.pdf
It is also available from NTIS (Order
No. PB2002-102037)
National Technical Information Service_
5285 Port Royal Road_
Springfield, VA 22161 _
Telephone:.
(703) 605-6000 (worldwide) _
(800) 553-6847 (U.S. only)_
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1000
^ 100 =
c ._.,-
s
•
0.
Q
o
10 -
0.35 0.67
1.34 2.65 4.58 7.75 12.2 17.7
Particle Geometric Mean Diameter (urn)
32.4
Figure 1. Differential Lead Particle Size Distribution During Wet Abrasive Blasting of Brick.
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