EPA/600/A^9S/201
Yaacov Mamane1, Robert D. Willis2, Robert K. Stevens3, and
John L. Miller4
SCANNING ELECTRON MICROSCOPY/X-RAY FLDORE6CENCE
CHARACTERIZATION OF POST-ABATEMENT DD8T
REFERENCE: Mamane, Y., Willis, R. D., Stevens, R. K., and
Miller, J. L., "SCANNING ELECTRON MICROSCOPY/X-RAY
FLUORESCENCE CHARACTERIZATION OF POST-ABATEMENT DUST," Lead
in Paint. Soil and Dust; Health Risks. Exposure Studies.
Control Measures. Measurement Methods, and Quality
Assurance. ASTM STP 1226. Michael E. Beard and S. p. Allen
Iske, Eds., American Society for Testing and Materials,
Philadelphia, 1994.
ABSTRACT: Scanning electron microscopy (SEM) and laboratory
X-ray fluorescence (XRF) were used to characterize post-
abatement dust collected with a HEPA filter. Three size
fractions of resuspended dust (0-150 ^m, 2.5-15 ^m, and <2.5
jiirv) were collected on teflon filters and analyzed by energy-
dispersive XRF. Automated SEM was used to determine the
size, morphology, and chemistry of individual particles from
0.2 M^ to greater than 250 fim. Minerals associated with
construction materials, paint fillers, and soil were the
dominant species in all size fractions. Lead-rich particles
were found in all sizes and could be grouped into three
categories: lead-only (including lead oxide and lead
carbonate), mixed lead/minerals, and automotive lead.
Isolated lead oxide or lead carbonate particles derived from
paint pigments were the dominant form of the lead-bearing
particles in the size fraction <15 ^m.
KEYWORDS: lead, dust, scanning electron microscopy, X-ray
fluorescence, post-abatement, paint
'Associate Professor, Environmental Engineering Department,
Technion, Haifa 32000, Israel; Research Scientist, ManTech
Environmental, Research Triangle Park, NC 27709; 3Chief,
Source Apportionment Research Branch, U.S. Environmental
Protection Agency, Research Triangle Park, NC 27711; 4Senior
Consultant, US EPA, Research Triangle Park, NC 27711.
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INTRODUCTION
Knowledge of the sources, size-distribution, and lead
content of lead-bearing particles is critical to assessing
risk and controlling environmental lead exposure. Much
information can be learned from field samples by combining
bulk analytical techniques with microanalysis of individual
particles. This paper discusses results of a preliminary
effort to characterize a lead-rich post-abatement dust
sample using a combination of laboratory X-ray Fluorescence
(XRF) for bulk analysis and manual and computer-controlled
Scanning Electron Microscopy (CCSEM) coupled with energy-
dispersive X-ray microanalysis (EDX) for individual particle
analysis. XRF provides rapid, quantitative, multielement
analysis thus providing an "elemental context" for lead
measurements and enabling interelement relationships to be
investigated. Scanning Electron Microscopy is an excellent
complement to the XRF technique. Recent papers [1,2,3,4]
demonstrate the power of CCSEM in apportioning sources of
environmental lead based on size, morphology, and
composition of individual particles.
Major objectives in the present study were to determine
if lead concentrations varied as a function of particle size
and to identify sources for the lead-bearing particles.
EXPERIMENTAL METHOD
Sample Description
The sample used in this study, designated as dust D-5,
was prepared for the Atmospheric Research and Exposure
Assessment Laboratory of the U.S. Environmental Protection
Agency. The sample was developed for the purpose of
establishing protocols and evaluating methods for the
analysis of lead-contaminated dust. Details of the dust
collection, sample preparation, and bulk analysis of the
dust are given by Williams et al.[5]. The sample consisted
of lead-rich dust collected with a HEPA filtered vacuum
system during the abatement clean-up process in several
homes which had lead-based paint removed or encapsulated.
The majority of the dust particles were therefore expected
to be products of abatement activities. The bulk lead
concentration in D-5 was previously determined to be 4550
Mg/g of dust based on a round-robin analysis of the sample
by atomic absorption (AA) and inductively-coupled plasma
(ICP) techniques.
XRF Analysis
Energy-dispersive XRF analyses were carried out using
the XRF facility of the Source Apportionment Research Branch
-------
(SARB) of the EPA [6]. The XRF spectrometer measures ng/cm2
concentrations for elements heavier than magnesium for
aerosol samples collected on filter substrates. Quantitation
is based on thin-film standards containing known concentra-
tions of selected elements. Quality control standards
including NIST thin-film SRMs containing certified lead
concentrations were measured before and after the sample
analyses to monitor changes in the operating condition of
the spectrometer and as additional calibration checks.
Samples were prepared for both XRF and SEM analysis by
aerosolizing sieved fractions of the dust and collecting the
dust on teflon or polycarbonate membrane filters. Similar
procedures for preparing XRF and SEM samples were used by
Batterman et al.[7] in characterizing soils and street dust.
The parent D-5 material had been sieved at 60 mesh to remove
particles >250 jim [5]. Prior to resuspension the dust was
manually sieved a second time by the authors into two size
fractions: 150-250 /im and below 150 ^m. Figure 1 shows the
particle resuspension chamber. Dust sample was introduced
from the top of the chamber. The chamber was designed such
that particles smaller than about 30 ^m aerodynamic diameter
were suspended in the chamber by air forced through the
glass frit at the base. It is possible that the original
size distribution of the D-5 dust was altered due to mass
fractionation in the resuspension process, but such effects
were beyond the scope of this study; some preferential loss
of smaller particles for example might be expected due to
electrostatic forces between particles and the system walls.
A Versatile Air Pollution Sampler (VAPS) [8,9] was
connected to the glass resuspension chamber via a PM-15
inlet operating at 32 1pm. The purpose of the VAPS was to
generate XRF and SEM samples in different size fractions.
Particles entering the inlet impinged on a virtual impactor
with a cut-point of 2.5 /im, were partitioned into a coarse
fraction (2.5 to 15 /im, aerodynamic diameter) and two fine
fractions (<2.5 pm), and were collected on pre-weighed 47mm
teflon filters. To avoid making large corrections for X-ray
attenuation, dust loadings for XRF samples were limited to
less than 200 M<3 cm'2. Thus, the quantity of dust collected
on each filter ranged between 0.1 mg and 2 ing.
Nine aliguots of the fine sieved material were
resuspended and analyzed by XRF. The nine samples are
summarized in Table 1 below and included four fine frac-
tions, three coarse fractions, and two "total" fractions.
The latter were collected by removing the PM-15 inlet and
replacing the VAPS with a single filter holder operating
with a flow of 25 1pm; "total" fraction samples in principle
included particles ranging in size from zero up to the
maximum particle size (nominally 150 /im) of the fine sieved
dust. "Total" filters were not expected to proportionately
-------
Dean
Excess Air
v_7
X
PV-15 Intel
32 L/mm
t t
of
Nyciepore •
Finer
t t
/\
Fmt
Con-Be
t
Fine
Glass
Nuctepore Finer
Teflon Fiiief
m I 2.0 L/min
1
tSUmin
Pumps
FIGURE 1—Schematic diagram of the dust resuspension
chamber. Dust particles injected from the top of the
chamber were size-selected using a Versatile Air Pollution
Sampler (VAPS) and collected on filters for analysis by XRF
and SEM/EDX.
-------
represent the <150 jjm size distribution of the D-5 dust both
because the resuspension chamber was designed only to
aerosolize particles less than 30 fim and because the larger
particles have a higher probability of settling directly
into the sampling inlet. Therefore, data obtained from
"total" samples was interpreted only in terms of the
differences between "total" and fine or course samples.
Filter tare weights were measured after allowing the filters
to equilibrate for at least 12 hours in a temperature and
humidity-controlled room. After sampling, the loaded filter
was again equilibrated in the balance room for at least 12
hours before weighing.
TABLE 1—Post-abatement dust samples analyzed by XRF and SEM
Sample ID Particle Size, jim Analysis
Fl
F2
F3
F4
C2
C3
C4
Tl
T2
F5
C5
FS1
CS1
0 - 2. 5"
0 - 2.5'>
0 - 2.5'>
0 - 2.5"
2.5 - 15 '>
2.5 - 15 »
2.5 - 15 »
0 - 150 ])
0 - 150 '>
0.2 - 4*
1.5 - 15 2)
5 - 50*
40 - 35025
XRF
XRF
XRF
XRF
XRF
XRF
XRF
XRF
XRF
CCSEM
CCSEM
CCSEM
CCSEM
Notes: 1) Aerodynamic diameter.
2) Geometric diameter.
Four additional samples were prepared for automated SEM
analysis. Samples F5 and C5 (Table 1) were made with
resuspended dust as described above but collected on
polycarbonate nuclepore filters for improved SEM imaging.
Samples FS1 and CS1 were prepared by manually sprinkling
fine sieved dust (<150 ^m) and coarse sieved dust (150-250
^m) respectively directly onto carbon planchets for SEM
analysis. No attempt was made to preserve the original size
distribution of the dust. The particle sizes given in Table
1 for the four SEM samples are the effective diameter
criteria used by the SEM to search for particles in the
automated mode.
SEM samples were analyzed by computer-controlled
SEM/EDX at R.J. Lee Group, Inc. (Monroeville, PA). The
resulting particle data and image files were processed and
interpreted at the EPA using the Zeppelin Microimaging
System (R.J. Lee Group, Inc.) developed for interpreting
-------
CCSEM data off-line. The software assigns a chemical
classification to each particle based on the four dominant
elements in the particle's X-ray spectrum. Data for each
sample are then summarized in the following tables:
1. Number of particles in each chemical class,
percentages, and average particle geometric diameter.
2. Size, area and mass distribution of particles by
average diameter and chemical class. (A density is assigned
to each particle based on its elemental composition).
3. Average elemental composition of the chemical
classifications provided in the first table.
4. Mass and number distribution by aerodynamic
diameter.
RESULTS
XRF Analysis
Elemental concentrations in ng/cm2 were measured by XRF
for the nine resuspended dust samples listed in Table l.
These values were converted to Mg/g concentrations using the
measured area and deposited mass for each filter. During
preparation of the samples it was found that a substantial
fraction of the deposited dust could be shaken off during
handling of the filter. The problem was most severe for the
heavily loaded coarse and total filters. Mass losses
occurring after the loaded filter was weighed and before XRF
analysis would cause concentrations to be underestimated as
well as bias the size distribution. In order to put bounds
on the measured concentrations, all teflon filters were
weighed again immediately after XRF analysis to determine
sample losses due to handling.
High concentrations of aluminum, silicon, sulfur,
potassium, calcium, titanium, iron, zinc, strontium, barium
and lead were measured in all three size fractions of D-5.
Figure 2 shows the estimated concentrations of these
elements in the three size fractions analyzed by XRF. The
abundances shown in Fig.2 are based on the assumption that
two-thirds of any dust mass losses due to handling occurred
before the XRF analysis. If larger fractions of sample were
lost from the coarse and total filters, their elemental
concentrations would be underestimated in Fig.2. Thus, the
apparent increase in elemental concentrations with
decreasing particle size may be artificial. Uncertainties
in the concentrations reported in Fig.2 are approximately +
20% for fine fraction data and ±40% for the coarse and
total fraction results.
Not surprisingly, calcium had the highest elemental
concentration in the post-abatement dust: calcium carbonate
-------
is the major constituent of cement, while gypsum (CaSO4) is
a major constituent of plaster and wallboard, and is
frequently used as a filler in paints. Some of the
aluminum, silicon, and potassium is probably associated with
soil-derived dust or street dust. SEM analysis of
individual particles suggests that aluminosilicates are also
associated with paint as paint fillers. Kaolinite and talc
for example are common fillers in paints. Sulfur, titanium,
iron, zinc, strontium, barium, and lead are all commonly
found in paint pigments.
03
O
C
(0
"D
C
D
ID
3.b-
-
.5-
•"
-
,5-
n.
,
S
-
1
|
S
!
P
1
1
1
"V
1
•i m
I
(
1
I
I
0-2.5 om
ED
2;5 -15 um
0 - 30 urn
Si (x.1) Ca(x,1) Fe Sr(xlO) Pb(x10)
S •' Ti Zn(x10) Ba(x10)
FIGURE 2—Estimated elemental concentrations measured
by XRF in three size fractions of post-abatement dust. The
increase in concentrations with decreasing particle size may
be an artifact associated with uncertainties in the sample
masses.
The estimated lead concentration in the fine fraction
samples is 2980 ± 600 pg/g. This is considerably less than
the bulk concentration of 4550 Mi/9 determined by AAS and
ICP and adopted as the consensus value. This may represent
a true difference between the lead concentration in the bulk
dust and in the fine fraction, or there may be additional
errors in the XRF analysis which have not been accounted
for. The above result is however similar to the bulk
concentration of 2485 M9/g determined by XRF in the round-
robin analysis of D-5 [5].
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SEM Analysis
Table 2 summarizes CCSEM results obtained on samples
F5, C5, and FS1 with the SEM operated in the secondary
electron node (SE). (Sample CS1 was analyzed only in the
backscattering mode). Particles were automatically sized
and analyzed by EDX. Images of particles containing high-Z
elements were automatically collected and stored on optical
disk for off-line review. Each particle was assigned to one
of several chemical classes based on the particle's X-ray
spectrum.
Table 2 shows that the composition of the three size
fractions is similar. As expected, minerals associated with
construction materials and paint fillers dominate the three
size fractions. The titanium-rich particles are probably
fragments of paint chips. Examination of individual
particles showed that the titanium was generally accompanied
by aluminum silicate and calcium or gypsum. Iron-rich
particles in general were also rich in calcium, silicon, and
sulfur.
TABLE 2—CCSEM analysis of D-5 samples (SE mode)
Sample F5 C5 FS1
/Particles
Size, ^m
385
0.2-4°
500
1.5-15"
232
5-50»
Chem. class Percent by number
Carbonates
Gypsum
Alum-Silicate
Quartz
Ti-rich
Fe-rich
Pb-rich
39
26
19
7
5
3
12>
36
22
24
10
4
3
0.52)
42
9
19
19
7
4
0.4
Notes: 1) Average geometric diameter.
2) Based on CCSEM analysis in Backscatter mode.
Fine and coarse fraction samples were analyzed by CCSEM
operating in the backscatter mode. The intensity of the
backscattered electron (BSE) signal increases with atomic
number. By setting a threshold on the BSE signal one can
exclude light elements from automated searches and greatly
enhance the efficiency of automated searches for particles
containing heavier elements such as iron, copper, zinc,
barium, and lead. With the BSE threshold set to exclude
elements lighter than iron, 100 fine and 161.5 coarse fields
-------
of view were scanned, equivalent, to analysis of a population
of 9600 and 18800 particles respectively. A total of 216
fine and 300 coarse metal-rich particles were found in the
BSE search. Examination of their x-ray spectra revealed
that the majority of these particles were iron-rich, lead-
bearing, or barium or zinc-rich particles associated with
paint materials. (Barium was almost always accompanied by
sulfur indicative of barium sulfate pigment).
The abundance of lead-rich particles in the fine and
coarse fractions was respectively around 1 and 0.5 particles
per field of view at a magnification of 1000X. Their
average sizes were 0.8 pm and 2.5 ^m respectively. Table 3
shows an estimate of the lead concentration in the fine and
coarse fractions based on the the BSE and SE data. The
results agree well with the XRF results for the same size
fractions.
TABLE 3—CCSEM-based estimate of Pb concentrations
in Fine and Coarse fractions.
Fraction
Fine Pb
Fine Total
Coarse Pb
Coarse Total
A
/Particles
per field "
0.99
96.25
0.48
116.28
B
Avg. dia.
(^m)
0.8
1.6
2.5
3.6
C
Density
(g/cm3)
5
2.7
5
2.7
Relative
Loading
(AxB3xC)
2.53
1064
37.7
14650
Notes: 1) Magnification •= 1000X.
Estimated Pb in Fine fraction = 2.53/1064 = 2380
Estimated Pb in Coarse fraction = 37.7/14650 = 2570
Fine sieved dust sprinkled by hand onto a carbon
planchet was analyzed in the size range of 5 to 50 Jim and
the results are as follows: 232 particles were found in 34
fields at magnification of 300X. In the SEM backscatter
mode only one 7.6 pm lead-rich particle was found in 35
fields of view representing an estimated concentration of
2400 ppm as calculated above. Time limitations precluded an
extended search of more fields in order to obtain better
statistics for this size range.
Lead-bearing particles—The speciation of lead
particles was one of the objectives of this study. Off-line
examination of the morphologies and X-ray spectra of the
lead-rich particles identified three major groups of
particulate lead:
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1. Particles Containing only Lead—This group
consisted of particles composed entirely of Pb, excluding O
and C. Many of these particles appeared as cubes or
hexagonals. This is the morphology of basic carbonate of
white lead, the pigment commonly used in leaded paints.
This was the most abundant class of lead-rich particles
found in the fine and coarse fractions of D-5. Manual SEM
showed the presence of these particles down to 0.25 jam. The
hexagonal morphology easily distinguishes these particles
from combustion-generated lead-only particles which
typically appear as chain aggregates. Figure 3 is a
photomicrograph of a typical lead carbonate particle.
000
5.000
JO. 000
15. 000
20. 000
ENERGY
keV
FIGURE 3—Scanning electron micrograph and X-ray
spectrum of a lead carbonate particle in D-5. The hexagonal
symmetry is characteristic of basic white lead carbonate
coitunonly used in paint pigments.
-------
2. Mixed Lead/Minerals—Minerals enriched in lead,
apparently as lead oxide or lead carbonate particles
attached to gypsum, calcite, or aluminosilicate surfaces
were found in all size ranges in the samples analyzed.
These are probably fragments of gypsum wallboard or other
construction materials that had been painted with leaded
paint. Figures 4 and 5 are photomicrographs of paint chips
rich in lead.
000
5.000
10.000
15. ODD
20. ODD
ENERGY
KgV
FIGURE 4—Backscattered electron image of a leaded
paint chip approximately 200x300 ^m. Areas rich in heavy
elements appear bright in the BSE mode. X-ray analysis of
the bright areas showed high lead concentrations. The X-ray
spectrum above was collected from an area adjacent to the
lead-rich region and indicates calcium and sulfur (probably
as gypsum), titanium, and aluminum silicate.
-------
5.000
10. 000
15. 000
20. 000
ENERGY
keV
FIGURE 5—Secondary Electron (top) and Backscattered
Electron (bottom) images of a leaded paint chip. The bright
ridge in the BSE image was rich in lead, zinc, barium, and
calcium as shown in the X-ray spectrum. Analysis of areas
adjacent to the lead-rich region showed gypsum, titanium,
and aluminum silicate.
-------
3. Automotive Lead—Because the D-5 dust sample was
comprised of post-abatement dust, the contribution from
street dust vas expected to be snail. Nevertheless, several
particles containing both lead and bromine and possibly
associated vith automotive emissions vere found in D-5.
These particles vere all smaller than three microns.
DISCUSSION AUD CONCLUSIONS
The primary objective of this limited study vas to
characterize post-abatement dust using a combination of
laboratory XRF for bulk analysis of size-selected fractions,
and SEM/EDX for analysis of individual particles, especially
lead-rich particles. The results confirmed the expected
dominance of construction-related and paint-derived (pigment
and mineral filler) particulates in the post-abatement dust.
Approximately 1% of the 9600 fine-fraction particles
(0.2-4 pm) and 0.4% of the 18800 coarse particles
(1.5-15 pm) analyzed by CCSEM vere lead-rich. In both size
fractions the majority of these particles vere isolated lead
oxide or lead carbonate particles derived from paint
pigments. In the coarse fraction a larger fraction of the
lead appeared as lead carbonate particles attached to other
minerals or as mixed lead/mineral particles.
One of the goals in this study was to determine how
lead concentrations vary with particle size. DeVoe at NIST
has recently measured lead concentrations in sieved
fractions of lead-rich dusts and found the highest lead
concentrations in particles less than 50 ^m [10]. This
finding is consistent with the high concentration of lead
oxide or lead carbonate particles observed by CCSEM in the
size fraction below 15 M»* Quantitative differences, if
any, in the lead content of D-5 in the fine, coarse, and
total size fractions analyzed by XRF were unfortunately
obscured by the large uncertainties in the mass deposited on
the XRF samples. Also, because of probable mass
fractionation effects associated with the particle
redeposition process, the size distribution of the analyzed
samples cannot be assumed to be representative of the
original dust.
Problems which limited the present study should be
minimized in future studies vith the recent acquisition of a
new XRF spectrometer by the Source Apportionment Research
Branch. The new system will enable quantitative,
multielement analyses on bulk dust samples without
restriction to particle size, thus eliminating the need for
resuspension. The ability to analyze larger samples will
minimize the potential for non-representative sampling which
may have contributed to uncertainty in the XRF data.
Additional computer-controlled SEM/EDX analysis of samples
collected from fluidized bed resuspensions should further
-------
enhance our ability to characterize and determine the
sources of lead particles in the environment.
REFERENCES
[1] Casuccio, G. S., Demyanek, M. L., Dunmyre, G. R.,
Henderson, B. c., and Stewart, I. M., "Characterization
and Identification of Lead-Rich Particles: A First Step
in Source Apportionment," Proceedings of the 204th
Symposium of the American Chemical Society, Washington
DC, August 23-2S, 1992, in press.
[2] Vander Wood, T. B. and Brown, R. S., "The Application
of Automated Scanning Electron Microscopy/Energy
Dispersive X-ray Spectrometry to the Identification of
Sources of Lead-Rich Particles in Soil and Dust,*1
EnvironmentalChoices Technical Supplement. July/August
1992, pp. 26-32.
[3] Hunt, A., Johnson, D. L., Watt, J. M., and Thornton,
I., "Characterizing the Sources of Particulate Lead in
House Dust by Automated Scanning Electron Microscopy,"
EnvironmentalScience and Technology. Vol. 26, No. 8,
1992, pp. 1513-1523.
[4] Johnson, D. L. and Hunt, A., "Speciation of Lead in
Urban Soils by Computer Assisted SEM/EDX - Method
Development and Early Results," Proceedings of the 1993
Boulder Conference on Lead in Paint, Soil, and Dust,
Boulder CO, July 25-29, 1993, this publication.
[5] Williams, E. E., Binstock, D. A., Estes, E. D., Neefus,
J. D., Meyers, L. E., and Gutknecht, W. F.,
"Preparation and Evaluation of Lead-Containing Paint
and Dust Method Evaluation Materials," Proceedings of
the American Chemical Society Symposium on Lead
Poisoning in Children: Exposure, Abatement and Program
Issues, Washington DC, August 24-25, 1992, in press.
[6] Dzubay, T. G., Stevens, R. K., Lewis, C. W., Hern, D.
H., Courtney, W. J.f Tesch, J. W., and Mason, M. A.,
"Visibility and Aerosol Composition in Houston, Texas,"
EnvironmentalScience and Technology. Vol. 16, 1982, p.
514.
[7) Batterman, S. A., Dzubay, T. G., and Baumgardner, R.
E., "Development of Crustal Profiles For Receptor
Modeling," Atmospheric Environmentf Vol. 22, No. 9,
1988, pp. 1821-1828.
[8] Gofer, W. R. Ill, Stevens, R. K., Winstead, E. L.,
Pinto, J. P., Sebacher, D. I., Abdulraheem, M. ¥.,
Al-Sahafi, M., Mazurek, M. A., Rasmussen, R. A.,
-------
Cahoon, D. R., and Levine, J. S., "Kuwaiti Oil Fires:
Compositions and Source Smoke," Journal Of Geophysical
Research. Vol. 97, 1992, pp. 14521-14525.
[9] Stevens, R. K., Pinto, J., Conner, T. L., Willis, R.,
Rasmussen, R. A., Mamane, Y., Casuccio, G., Benes, I.,
Lenicek, J., Subrt, P., Novak, J., and Santroch, J.,
"Czech Air Toxics Study (CATS): Project Summary,"
Proceedings of the 86th Annual Meeting of the Air and
Waste Management Association, Denver CO, June 13-18,
1993, in press.
[10] Jim DeVoe, private communication.
ACKNOWLEDGEMENTS
The assistance of Mr. Bradley Henderson of R.J. Lee
Group, Inc. in the analysis of samples by CCSEM, and Mr.
Robert Kellogg of ManTech Environmental Technology Inc., in
the analysis of filter samples by XRF is gratefully
acknowledged. The authors are grateful to Ms. Karen Blume
for her assistance and many helpful suggestions during the
course of the project.
DISCLAIMER
The information in this document has been funded in part by
the U.S. Environmental Protection Agency under contract
(#68-09-0131) to Acurex and contract (#68-DO-0106) to
ManTech Environmental Technology, Inc. It has been subject
to Agency review and approved for publication. Mention of
trade names or commercial products does not constitute
endorsement or recommendation for use.
-------
TECHNICAL REPORT DATA
1. REPORT NO.
EPA/600/A-93/201
2.
4. TPTLE AND SUBTITLE
SCANNING ELECTRON MICROSCOPY/X-RAY FLUORESCENCE
CHARACTERIZATION OF POST-ABATEMENT DUST
7. AUTHOR(S)
Yaacov Mamane', Robert D.
John L. Miller"
Willis2, Robert K.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
'Technion, Haifa, Isreal 32000
:Mantech Environmental Technology Inc., Res<
Triangle Park, NC 27709
3Atmospheric Research and Exposure Assessmei
Laboratory, US Environmental Protection Age
Research Triangle Park, NC 27711
"Senior Consultant, US Environmental Proted
Agency, Research Triangle Park, NC 27711
Stevens3,
=arch
it
ncy,
:ion
12. SPONSORING AGENCY NAME AND ADDRESS
Atmospheric Research and Exposure Assessment
Laboratory, Office of Research and Development,
US Environmental Protection Agency
Research Triangle Park, NC 27711-0047
5. REPORT DATE
6.PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT
NO.
10.PROGRAM ELEMENT NO.
1 1 . CONTRACT/GRANT NO.
In-house
13. TYPE OF REPORT AND PERIOD COVERED
Journal Article
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Scanning electron microscopy (SEM) and laboratory X-ray fluorescence (XRF) were
used to characterize post-abatement dust collected with a HEPA filtered vacuum.
Three size fractions of resuspended dust (0-30 pm, 2.5-15 jjm, and <2 . 5 /jm) were
collected on teflon filters and analyzed by energy-dispersive XRF. Automated SEM
was used to determine the size, morphology, and chemistry of individual particles
from 0.2 ^m to greater than 250 ^m. Minerals associated with construction
materials, paint fillers, and soil were the dominant species in all size fractions.
Lead-rich .particles were found in all sizes and could be grouped into three
categories: lead-only (including lead oxide and lead carbonate), mixed
lead/minerals, and automotive lead. Isolated lead oxide or lead carbonate
particles derived from paint pigments were the dominant form of the lead-bearing
particles in the size fraction <15 pm.
17.
KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
b. IDENTIFIERS/ OPEN ENDED c.COSATl
TERMS
19. SECURITY CLASS (This Repori) 21. NO. OF PAGES
UNCLASSIFIED 16
20. SECURITY CLASS (TJiis Page) 22. PRICE
UNCLASSIFIED
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