EPA-650/4-74-015
September 1973
Environmental Monitoring
Series
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EPA-650/4-74-015
SURVEY OF MANUAL METHODS
OF MEASUREMENTS
OF ASBESTOS, BERYLLIUM, LEAD,
CADMIUM, SELENIUM, AND MERCURY
IN STATIONARY SOURCE EMISSIONS
by
D. M. Coulson, D. L. Haynes,
M. E. Balazs, and M. P. Dolder
Stanford Research Institute
Menlo Park, California 94025
Contract No. 68-02-0310
ROAP No. 26AAG
Program Element No. 1HA327
EPA Project Officer: M. Rodney Midgett
Quality Assurance and Environmental Monitoring Laboratory
National Environmental Research Center
Research Triangle Park, North Carolina 27711
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
September 1973
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This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the Agency,
nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
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CONTENTS
ACKNOWLEDGEMENTS y5
I INTRODUCTION 1
II SUMMARY OF WORK ACCOMPLISHED 2
III SELECTION OF METHODS OF ANALYSIS 4
A. Asbestos 4
B. Beryllium 10
C. Lead 14
D. Cadmium 15
E. Selenium 20
F. Mercury 21
IV RESULTS OF LABORATORY AND FIELD TESTING 30
A. Asbestos 30
B. Beryllium 35
C. Lead and Cadmium 41
D. Selenium 47
E. Mercury 49
F. Data and Calculations for Lead, Cadmium, and Beryllium
Field Samples 49
REFERENCES 55
APPENDIX 1 BACKGROUND INFORMATION 1-1
APPENDIX 2 MANUAL METHODS FOR MEASURING ASBESTOS, BERYLLIUM, LEAD,
CADMIUM, SELENIUM, AND MERCURY IN SAMPLES COLLECTED IN
STATIONARY SOURCE EMISSIONS 2-1
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FIGURES
1 Asbestos Sampling Location at Bag House Exhaust 31
2 Photomicrograph of Asbestos Particles 33
3 First Beryllium Sampling Location 38
4 Second Beryllium Sampling Location 39
5 Lead and Cadmium Sampling Site 45
2-1 Sampling Train 2-2
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1
2
3
4
5
6
7
8
9
10
11
12
13
5
23
25
25
27
34
36
40
44
46
48
48
50
TABLES
Criteria for Selection of Analytical Methods
Free Energy Values for Various Reactions
S02 Removal at Various Temperatures
Hg Removal at Various Temperatures
Mercury Content of Smelter Flue Gas
Counts of Asbestos Particles in Samples Collected at Asbestos Mill
Laboratory Measurements of Beryllium Samples
Measurements of Beryllium Field Samples
Laboratory Measurements of Lead Samples
Measurements of Lead and Cadmium Field Samples
Absorption Spectrum of a Solution of 4,5-Benzopiazselenol in
Toluene
Laboratory Measurements of Selenium
Lead, Cadmium, and Beryllium Sampling Data
V
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ACKNOWLEDGMENTS
Acknowledgment is made to Ilsabe C. Niemeyer for her work on the
electron microscopic method of analysis for asbestos. Also appreciated
is the assistance provided by Louis J. Salas and August C. Pijma in
the collection of field samples.
Appreciation is extended to Thomas E. Ward of the EPA who trained
the SRI sampling team in the use of the EPA particulate train; also
to John B. Clements, William J. Mitchell, and Rodney Midgett who reviewed
the drafts and supplied many helpful suggestions.
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INTRODUCTION
Certain reactive elements and some of their compounds and asbestos
are found to cause pronounced deleterious effects on human health. Fur-
thermore, some evidence indicates that exposure to even low concentrations
©f toxic substances such as asbestos, beryllium, lead, cadmium, selenium,
and mercury can result in their being assimilated into vital organs, caus-
ing subsequent malfunction, irreparable injury, or death. Thus, these
toxic substances must be measured and controlled in man's environment.
The purpose of this study is to evaluate existing manual methods for
analyzing asbestos, beryllium, lead, cadmium, selenium, and mercury and
from this evaluation to provide the best and most practical set of ana- !
lytical methods for measuring emissions of these elements from stationary
sources.
The work performed in this study.was divided into two phases.
Phase I was limited to surveying sources of information and summarizing
the findings in terms of existing methods; totally new methods were not
developed. However, in the case of asbestos amd mercury it was necessary
to modify existing methods significantly, and some laboratory and field
testing was performed during Phase I to develop these two methods.
Phase 11 was concerned with the testing, evaluation, and modification
of the methods of analysis developed during Phase I. Both laboratory and
field tests were conducted during this phase of the work.
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SUMMARY OF WORK ACCOMPLISHED
During Phase I of this study sources of information were searched
for methods of analysis for asbestos, beryllium, lead, cadmium,
selenium, and mercury that would be suitable for analyzing stationary
source emissions. The primary sources of information were the technical
literature, telephone and direct interviews with staff members of
companies that are probable stationary sources of emissions of the
pollutants, and contact with the Project Officer assigned by the
Environmental Protection Agency (EPA). During the literature search we
obtained additional background information on the toxicity of the
pollutants in this study. This information is presented in Appendix 1.
Methods of analysis were then chosen on the basis of a survey of
current knowledge on methodology, ease of using the procedure, availability
of the equipment needed to perform the tests, sensivitity based upon
proposed EPA standards of emission and threshold limit values (TLV)
adopted by the American Conference of Governmental Industrial Hygienists
(ACGIH), and specificity requirements. One method was chosen for each
pollutant. A detailed discussion of how the methods of analysis were
selected is presented in Section III. These methods of analysis are
presented in Appendix 2.
Some laboratory and field testing was performed during Phase I for
methods of analysis that required modification of existing methods.
Much of the methodology for asbestos was newly formulated and laboratory
tested. It was also necessary to develop a S02 scrubber for use in the
mercury method because S02 interferes with the collection of mercury.
This scrubber was first tested in the laboratory and then field
tested at a zinc refinery.
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During Phase II the methods of analysis selected in Phase I were
tested, evaluated, and then modified if necessary. All methods were
initially tested in the laboratory. The asbestos method was tested
on samples collected at an asbestos mill. Field sampling was conducted
for beryllium at a beryllium machining facility, but only small amounts of
beryllium were collected. The methods for lead1 and cadmium were tested
successfully on samples collected at a municipal incinerator in Dade
County, Florida. No field tests were conducted for selenium because work had
been stopped on this pollutant before field testing began. Field
testing was performed on mercury in the development of the method of
analysis in Phase I, Further development of the methods of analysis
for asbestos and mercury probably should be made before they are ready
for routine use in measuring source emissions.
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Ill SELECTION OF METHODS OF ANALYSIS
Sources of information were surveyed to find the best and most
practical existing manual methods for measuring emissions of the pollutants
included in this study from stationary sources. The requirements of
major importance in the selection of methods of analysis, along with
their definitions and reason of importance, are listed in Table 1.
Considering these criteria and the emission standards proposed or
established by the EPA, we chose the following methods of analysis. A
method using electron microscopy was chosen for analyzing asbestos.
Atomic absorption spectroscopy methods were chosen for beryllium, lead,
and cadmium. A spectrophotometric method was chosen for selenium, and
flameless atomic absorption spectroscopy was chosen for mercury. The
reasons for choosing these methods and the other methods investigated
are described in this section.
A. Asbestos
The current knowledge of the health risks of asbestos in gas streams
was studied in an effort to determine which characteristics of asbestos
should be measured. There seem to be several different opinions on
the nature of toxic fibers. Some workers feel that the fibers must
be at least 5 ^ long to be pathogenic.1'2 Others feel that smaller
particles also represent a serious health risk. According to Schepers,3
The asbestos within the lung which matter, consists of
those fibrils which invade the alveolar walls, those
which reach the perivascular lymphatics and vascular
adventitia, and those which deposit below and within
the pleura. These are generally extremely delicate
fibrils, less than 0.2 ^ in caliber, and difficult
to detect through conventional microscopy.
Suzuki and Churz4 feel that submicroscopic fibers (fibers less than 1 ^
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Table 1
CRITERIA FOR SELECTION OF ANALYTICAL METHODS
Requirement
Definition
Importance
Sensitivity
Specificity
Precision
Accuracy
Range of
analysis
Stability
Ease of
handling
Time of
analysis
Cost
Availability
of equipment
Amount of material that
gives a specified response.
Ability to measure only the
substance of interest by
eliminating interferences.
Error of the method (often
expressed as the coeffici-
ent of variation) estab-
lished by the analysis of
many samples containing
equivalent amounts of the
species of interest.
Ability to determine the
true value.
Concentration range in
which reliable results can
be obtained.
Ability of the materials to
remain intact over a period
of time.
Skills required to prepare
the sample and execute the
analytical methods.
Time required to analyze
one sample completely.
Actual monetary expenditure
for materials, equipment,
and personnel needed.
Ability to purchase the re-
quired equipment and mate-
rials needed for an anal-
ysis.
5
To establish a level of sensitivity
of amounts of material collected for
analysis.
Interfering substances can cause
false interpretation of data.
Lack of precision in a method can
make it essentially useless.
Most analyses are performed to de-
termine actual amounts of specific
substances in specific samples.
Analyses can yield false results if
concentrations are too high or too
low.
Analytical use of decomposed materi-
als results in false data.
Methods requiring advanced skills
reduce precision and must be car-
ried out by highly trained per-
sonnel.
Examination of numerous samples
necessitates a reduced analysis
time for completion of each sample.
Examination of numerous samples
necessitates low cost per sample.
Widespread testing requires easily
obtainable supplies.
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long) are responsible for most of the biologic effects of asbestos.
Therefore, we concluded that it would probably be necessary to determine
particle counts and particle size distribution to get meaningful results
that could be related to the effects on human health.
Schepers also believes that chrysotile fibers may be more damaging
than crocidolite or amosite because the diameter of chrysotile fibers
is smaller than that of other asbestos types. We decided to concentrate
primarily on the measurement of chrysotile fibers on the basis that
approximately 95$ of the asbestos produced is chrysotile.
In studies using chrysotile particles from a dust generator on guinea
pigs and rats, Holt et al.5 expressed the opinion that particles of
ultramicroscopic dimensions are at least as lethal as long fibers.
Ayer and Lynch6 reported that asbestos factory dust contains a
significant portion of motes and that this portion of the respirable
dust decreases in the later operations of asbestos production. They
state that
Fibrous chrysotile asbestos is perhaps of the same
order of toxicity as quartz, while the accompanying
nonfibrous serpentine and nonasbestos minerals (with
notable exceptions, such as quartz) may be considered
"inert" dust... since fibers cause asbestosis, a count
of fibers from an air sample provides a reasonably
direct index of the asbestosis hazard. The British
asbestos industry utilizes an informal limit of 4 fibers
longer than 5 ^ per cc. Until it has been definitely
determined which size fibers cause lung disease, it
would seem preferable to use an index which included
as much of the respirable size spectrum as feasible
rather than counting only a particular size fraction.
Because of the small diameters of the asbestos fibers,
the count obtained will be dependent upon the resolu-
tion of the microscopic system employed as well as
efficiency of the collecting system. Counts by the
4 mm objective and phase contrast illumination which
we use, for example, give approximately one-quarter
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the number of fibers longer than 3 and one-twelfth
the number of total fibers as revealed by electron
microscopy of the same sample. Using a 2 ram objec-
tive we see a larger number of fibers and with a 16 mm
objective we see fewer.
The EPA has not set allowable emission standards for asbestos be-
cause toxic levels are difficult to delineate and because sampling and
analytical techniques for source emissions are lacking for this substanoe.
Standards promulgated by the EPA are designed to limit emissions into the
atmosphere7 and are expressed in terms of required control equipment.
In discussing the respirable fraction of dusts based on general
considerations, Ayer and Lynch suggested that
The most applicable for asbestos sampling appear
to be those suggested to the Office of Health and
Safety of the U.S. Atomic Energy Commission by a
group of consultants on January 18-19, 1961, and
adopted in AEC regulations. They are:
Percent Particle Diameter, y
Respirable (unidensity sphere)
100% < 2
75 2.5
50 3.5
25 5
0 10
Although not originally proposed for nonradioactive
material, these criteria have been used for asbestos
by others.
On the basis of the preceding discussion and a considerable volume
of literature, we concluded that the results of analytical methods for
asbestos in gas streams should possess the following characteristics if a
fair measure of the risks to man is to be represented:
• The results should differentiate between asbestos and non-
fibrous materials of the same chemical composition.
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• The method should be sensitive to individual asbestos
particles of all sizes in the respirable fraction, which
includes all asbestos particles smaller than 5 fj, in their
longest dimensions as well as some longer fibers that are
respirable.
• If a mass sensitive method not sensitive to individual
particles is used, the results must give a good correla-
tion with particle counts and particle size distribution.
To meet these requirements we need a method of sampling that would
collect or in some way observe essentially all the asbestos particles
shorter than 5 u as well as longer fibers. Since we were interested
only in fibers and not motes, the method of detection and measurement
had to be selective.
Most of the good work in the literature on analysis for asbestos
in gas streams entails the use of optical microscopy or electron micro-
scopy. However, before choosing either method for the present study, we
looked at the alternatives as well.
Atomic absorption could be used to measure the magnesium content
of an aggregate sample, but it would not give any information concern-
ing the number and size of the chrysotile fibers.® This method should
not be used except when other magnesium-containing dust particles,
such as serpentine, are known to be absent. Thus, the outlook for
the use of atomic absorption analysis in monitoring was not encouraging.
Neutron activation analysis yields results similar to those of atomic
absorption.8
Gadsden et al.9 described infrared measurements of asbestos col-
lected from air samples based on the sharp absorption band at 2.72
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These measurements could be used if a correlation between the intensity
of this absorption and the health hazard could be established for certain
types of samples. However, it seemed unlikely that such a correlation
could be established except for the monitoring of certain processes in
asbestos manufacturing operations in which interfering materials are
known to be insignificant. The method requires a sample containing at
least 20 jig of asbestos.
X-ray diffraction has been used by Goodhead and Martindale10 to
identify and measure large samples of asbestos fibers. Their method
requires a sample in the milligram range and again, as with infrared
measurements, gives a measure of the amount of asbestos rather than
the number of particles. Thus, it seemed unlikely that this method
would be very useful in health risk measurement.
Addingley11 described the use of a Royco particle counter for meas-
uring air in asbestos manufacturing factories. The Royco instrument
gives satisfactory counts for particles over 1 )i in diameter (equivalent
diameter). Addingley, however, indicated that all particles of asbestos
or nonasbestos are counted by this instrument and that normal pollution
of the atmosphere may contribute significant errors in the particle
size range from 0.3 to 1 (A equivalent diameter. In spite of these
drawbacks, Addingley concluded that at the time of this evaluation the
Royco particle counter was the best method for testing dust in asbestos
factories. The lack of specificity of the method and the presence of
considerable amounts of submicron particles in normal gas streams combine
to limit the use of the Royco particle counter to the special cases in
which little interference is observed. The Royco instrument may be very
useful in determining the sampling times required for more quantitative
microscopic and electron microscopic examinations. Thus, it could be
used to good advantage in making decisions on gas flow rates and sampling
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times with Nuclepore® or MilliporeJ® filters. Before the Royco
instrument can be evaluated as a health hazard monitor, more research
should be done on its use for airborne asbestos particle monitoring in
asbestos factories.
Considering the current knowledge of methods for monitoring airborne
asbestos and the lack of definitive information on health hazards, we
concluded that the method for obtaining useful data on the measurement of
asbestos sources must include both identification and size distribution
as well as particle counts. Thus we chose electron microscopy as the
most promising method.
The technical literature discriptions of the method of preparing
samples for examination with an electron microscope were found to be brief
and inadequate. After several telephone conversations with people active
in the field, we were able to get satisfactory results in the laboratory.
The procedure given in Appendix 2 for mounting a sample on an electron
microscope grid is based on the work of Frank et al.12 with modifications
suggested by Murchio.13
B. Beryllium
Several methods have been developed for the microquantitative
analysis of beryllium. All methods except colorimetry employ essentially
the same gas sampling techniques, i.e., a technique that uses a Millipore®
*
or cellulose paper filter to catch the beryllium contaminant. The filter
is then processed by wet or dry oxidation, and the residue is treated as
necessary for the quantitative determination used, i.e., colorimetry, gas
chromatography, atomic absorption, fluorometry, emission spectrometry, or
#
Recent studies by EPA personnel have demonstrated that beryllium
particles penetrate filters under certain conditions. Therefore,
collection efficiency of filters is uncertain.
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detection by nuclear radiation. The processing of the filter can become
lengthy if many other metals interfere with the identification and mea-
surement of beryllium.
Colorimetry must take into consideration metal contaminants that
interfere with the determination of beryllium. To reduce interference
from other metals, McClosky14 developed a method using aluminon.
reagent (ammonium aurintricarboxylate) to replace the Zenia method.
McClosky's method improved the detectability from 2.5 yg to 0.3
Although this method is useful, it is lengthy and requires quantitative
precipitation, filtering and washing, redissolving, and finally a 60-
minute color development period before measurements are taken.
Krivoruchko15 presents another colorimetric method that is equally as
complex, but ultimately sensitive and useful.
Gas chromatography is a useful method in that the sample needed for
sensitive detection need be only one-third the size of that needed for
colorimetry;16 however, a relatively lengthy preparation is required to
+ 3 +3
remove interfering ions (Fe and A1 ) from gas chromatography samples.
Quantitative extractions are used that can be, at best, a source of error.
Wolf et al.17 have done some preliminary work on beryllium in ambient air.
(
i
With the advent of the nitrous oxide-acetylene flame in atomic ab-
sorption, Bokowski18 has used this tool for the microquantitative analysis
of beryllium. This method has a sensitivity of 0.03 ^g/ml/%-absorption
and is not affected by interfering ions as they are easily quenched
with 8-hydroxyquinoline. Many metals enhance the absorption, thereby causing
positive errors, as is shown in the paper by Fleet et al.19 In amounts up
4000 Ug/ml this enhancement can be masked by making the solutions 10,000
^g/ml in potassium.
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Fluorometry has also served as a useful tool in the determination
of beryllium; however, it requires several quantitative treatments before
the final measurement is actually made because, like colorimetry, it also
suffers the problems of interfering ions. Buffers, diethylenetriamine-
pentacetic acid, and other chelating substances are used to remove these
ions. Initially, when fluorometry was used, some anomalous results would
occur. Sill et al.20 identified the cause as the absorption of
beryllium on the walls of glass containers by anion exchange centers.
They corrected the problem by storing all glass containers in 2 M hydro-
chloric acid. This procedure cleaned the anion exchange centers from the
walls of the glass containers. Although sensitivity was enhanced by the
use of various filters, some difficulty with interfering ions was still
experienced.
Emission spectrometry is one of the most sensitive and useful methods
found in the literature for the analysis of beryllium. In this method,
as in all the methods mentioned, the sample is collected on a cellulose
filter paper. Hie sample is then either wet digested and the solution
containing the beryllium is reduced to 1 ml or less and placed in an ab-
sorbing carbon electrode for sparic emission, or it is dry ashed and
the residue is placed in a carbon electrode. Fitzgerald21 merely
rolled the filter paper containing the sample and placed it in the arc to
be oxidized while being analyzed. The emission spectrometric method of
analysis is sensitive (0.001 /|g),22 quick (1 sample per minute), and gen-
erally requires less handling or treatment of the sample than colorimetry,
gas chromatography, and fluorometry.
Churchill and Gillieson,23 Webb et al.,24 and Rozsa et al.25 have
developed direct reading spectrograph!c systems in which the gas sample
is drawn into a spark chamber or intermittent arc and the beryllium
determination is made by comparison with the background. By careful
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0
adjustment in focusing on the Be 3130.416 A line, interference from other
elements is avoided. The main difficulty is sensitivity, since in this
system material cannot be accumulated as it can in filter paper collecting,
In reference to the direct spectrographic monitor developed by Churchill
and Gillieson, Darwin and Buddery26 commented that the prototype machine
was an excellent tool when in working order but the amount of highly skilled
maintenance it required made it impractical for pilot plant use.
Brauman.27 at the Rocket Propulsion Laboratory at Edwards AFB
developed a remarkable beryl Hum-in-air monitor based on the reaction
Be9 + a-»N+y+C12. The instrument is costly and for extreme sensi- 1
tivity the time for analysis is significant (2 pg requires 60 minutes). Al-
though this monitor is interesting and useful, it Is impractical for general use.
The EPA has established an emission limit of 10 g per 24-hour day as
the emission standard for certain beryllium—emitting stationary sources.28
As an option, the affected sources may elect to comply with an emission
limit not to exceed amounts that fesiilt in 4rt dutjjlant concentration of
0.01 jig of beryllium per cubic meter of air averaged over a 30-day period.
Sample volume must be at least 75 cubic feet, and sampling time must be
at least two hours* Sampling procedure adjustments appropriate
to the emission capacity of the source will be necessary for- analysis
of a number of sources with a wide range of emission capabilities.
In considering all the methods mentioned above in conjunction
with ease of handling, sensitivity, time required to obtain results, and
cost of method and required equipment, it appears that atomic absorption
is the method of choice in analyzing beryllium samples. A detailed method
of analysis based on the use of atomic absorption spectrophotometry was
prepared and is presented in Appendix 2.
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C. Lead
Numerous descriptions of the method for particulate lead deter-
minations in gas streams have been found in technical literature. All
methods use a membrane or glass fiber filter as the trapping medium for
sample collection. The lead sample is generally removed from the filter
by acid washes or is ashed to remove organic matter and then treated with
acid. In X-ray fluorescence spectroscopy,29"31 however, the analysis is
performed directly on the membrane or glass filter. Impurities in the
filter do interfere and the limit of detection is only 1 ^g. Also,
equipment used is specialized and requires that the data be obtained
and interpreted by an experienced technician.
Spectrophotometric determinations of lead using the dithizone32-35
and hydroxyquinone36 complexing agents are very precise and are carried
out on the acid washes obtained from membrane or glass fiber filters. Since
some other inorganic metal compounds interfere with the method, chemical
separation is required before final spectrophotometric analysis. Hie
procedure must be performed by an experienced chemist and is lengthy and
tedious.
The ring-oven technique37 of lead analysis uses the precipitation
of lead raolybdate on filter paper and depends on visual and colorimetric
concentration determinations. Constant reference standards are imprac-
tical because the samples and standards are light sensitive. The method
has a detection range of 0.05 to 2 ^g Pb.
Emission spectrograph!c analysis38*39 has a sensitivity of better
than one part per 20 million for lead analysis in a continuous gas
monitoring system. It is applicable to a wide range of other metals.
However, the equipment used is specialized, and a high degree of analyt-
ical skill is required to perform a quantitative analysis.
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The polarographic method31'3e»40-43 of lead analysis is useful in
the range of 0 to 15 ^g/m3 (dissolved in 30 ml of solution or 0 to 0.5
|^g/ml/m3) in a gas stream and requires a square wave31'43 polarograph
to obtain good responses. Organic impurities and the presence of nitrate
ions interfere with the analysis. Although the method does have the ad-
vantage of multimetal analysis, the complexity of the technique and the
unavailability of polarography in many laboratories make the method
a poor choice for lead analysis.
Atomic absorption spectrometry44-s6 is very adaptable to lead anal-
ysis. After collection and aqueous extraction of the lead sample, atomic
absorption requires only dilution of the sample before analysis can pro-
ceed. Organic material must be removed if it is present. Although
interferences do exist, most of them can be eliminated during sample
preparation or in the measurement step. The method can detect amounts of
lead from sources as low as 0.03 /ig/m3 .
The EPA has not yet proposed emission standards for stationary
sources of lead. The TLV given by ACGIH is 200 jjg/m3.57'58 In the
absence of other standards, the method selected should have the capa-
bility for analyzing this concentration of lead.
Considering the availability, ease of operation, documentation in
the literature, and sensitivity, we chose the atomic absorption method of
analysis for particulate lead determinations in source emissions
(see Appendix 2).
D. Cadmium
The numerous methods available for analysis of cadmium source
emissions include atomic absorption, atomic fluorescence, ultraviolet
and visible spectroscopy, polarography, and titrimetric analyses.
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Atomic absorption methods,54>56»59-63 using an air-acetylene flame
o
and a cadmium hollow cathode lamp at 2288 A, can achieve a sensitivity
of 0.25 yg/ml/% absorption. In fact, the sensitivity for cadmium can
be increased to ng/ml by using dithizone as a chelating agent according
to the method of Sachdev and West.63 Other available modifications to
the atomic absorption spectrophotometer, such as a heated graphite at-
omizer, will increase the cadmium detection limits to several nanograms
per liter using only 20 samples.
In the analysis of cadmium by atomic absorption, Ramakrishna
et al.61 reported interferences caused by anions, such as B2042 ,
Si032-, Co32~, hco3~, and HAs042~. These interferences are effectively
overcome by acidification of the samples or by the addition of disodium
(ethylenedinitro) tetraacetate. Pulido et al.64 found that phosphate in
concentrations above 0.1 M could decrease the absorption and that sodium
chloride in concentrations above 0.01 M could increase the absorption;
however, concentrations this high are not likely to be encountered. If
necessary, the phosphate and NaCl interferences can also be removed by
extraction of cadmium with dithizone in a solution having an acidity of
pH 5 to 9. This treatment results in a higher cadmium concentration and
eliminates interfering salts.
Methods of atomic fluorescence spectroscopy65-76 are similar to
atomic absorption spectroscopy. Atomic fluorescence spectroscopy has a
cadmium sensitivity of 0.5 ng/ml. Currently, atomic fluorescence methods
utilize modified atomic absorption instruments or instrumentation com-
pletely fabricated in the laboratory, since commercial atomic fluoresoence
16
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instruments are nonexistent. Varian Techtron provides an adapter for
atomic absorption instruments, but it has not yet proved to be highly
satisfactory. Studies of 41 cations and 18 anions conducted by Cresser
and West68 and by Dagnall et al.69-70 showed cadmium interferences to be
minimal. Bratzel et al.65-66 showed that sulfate and phosphate tend to
enhance the atomic fluorescence signal, whereas aluminum decreases the
signal. As reported by Hobbs et al.,71 organics (which often present
problems in atomic absorption) do not interfere with cadmium measurements.
The method of atomic fluorescence spectroscopy may be more sensitive than
absorption when refined, especially when modifications in the burner head
and flame are incorporated. The usefulness of these modifications
has been illustrated by Winefordner and coworkers,77»78 They used a
total-eonsumption aspirator-burner and compared three flame compositions
for the analysis of various metals including cadmium. They reported a
cadmium detection limit of 0.2 ^g/ml in aqueous solutions when they used
an argon/hydrogen/entrained air flame.
Polarography41*42»79-83 has been used successfully for traoe metal
analysis of solutions containing several elements including cadmium.
Mann82 claims a practical cadmium sensitivity of 1 j/g/ml in a sodium per-
chlorate solution using a discontinuous voltage sweep for voltametric
determinations. Films of surface active compounds can interfere, but
this interference is minimized by the addition of chloride ion to the
solution. The rapid rate of reduction for cadmium further reduces the
effects of potentially interfering substances. Dubois and Monkmann41
reported "good" sensitivity for polarographic analyses of cadmium; how-
ever, no values were given.
Differential polarography83 is a technique in which the current
flowing in one polarographic cell is subtracted from that flowing in
another. One cell contains an accurately known solution of cadmium and
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the other the unknown cadmium solution; the small current difference can
be amplified and precisely measured. This technique is reported to im-
prove the precision of polarography considerably. Practical difficulties
in the method include exclusion of atmospheric oxygen. Other chemical
interferences were not reported. Minimum solution concentrations that
can be detected with the method aire about 10 jjg/ml.
Titrimetric analyses84-90 for traces of cadmium have been reported
using varied titrants and end point detection methods. Monk and Steed88
reported cadmium analysis in the range of 2.9 to 39.2 ^g using a mercury-
calomel electrode system with an EDTA titrant. The percentage of error
with this method ranged from 0.3 to 1.7%. At a pH of 10.5, cadmium con-
centrations of 3.5 and 21.3 j/g were analyzed with errors of 0.3 and 0.1%,
respectively. The method is most applicable to 10-20 ^g quantities of
cadmium with a coefficient of variation of a single determination between
0.5 and 1.0%. Other methods84'89 discuss variations of the EDTA titrant
method. These methods can be used to analyze for cadmium over a range of
4 to 20 ^tg with a standard deviation of 0.14 ^g. The method of Schone-
baum89 may be suitable for determining metals in organometallic
materials if rigid controls are maintained to obtain good accuracy. How-
ever, more studies are needed, and no specific comments are made regarding
cadmium compounds.
Spectrophotometry analysis of cadmium has been reported by Saltz-
man,91 Boltz and Havlena,92 and others. Saltzman uses dithizone as the
cadmium complexing agent with the addition of cyanide as a suppressant
for interfering metals. Hie colorimetric measurements were made on a
Beckman Model DU spectrophotometer in the visible range. Although nu-
merous reagents are used in the analysis, the system as described permits
a cadmium sensitivity of 0.05 ^g/ml. Anion interference was not
investigated.
18
-------
Boltz and Havlena92 describe an ultraviolet spectroscopic method in
which diethyldithiocarbamate is used as a chelating agent and the com-
plexed cadmium ion is extracted from aqueous solutions with chloroform.
The optimum concentration range of the method is 0.5 to 3 j^g/ml of cadmium
^ 3^, 2+ 2+ 3^. 2 +
in chloroform. Metal ions such as Ag , Au , Bi , Cu , Co , Cr , Fe ,
3+ 2+ 2+ 2+ 2+ 2+ 2+ 4+ 3+ 2 +
Fe , Hg , Mn , Mg , Ni , Pb , Sn , Sn , Sb , and Zn cause inter-
ferences, however, and must be removed if accurate results are to be
achieved.
The EPA has not established guidelines for stationary source emis-
sion standards on cadmium. The TLV given by ACGIH is 83 ^g/m3 for cadmium
in particulates and 166 jxg/ra3 for cadmium in dust.93 In the absence of
other guidelines, the method of analysis selected should be capable of
this concentration of cadmium.
Considering these methods for cadmium analysis, the requirements
set forth in Table 1, the availability of equipment, and emission levels,
we selected atomic absorption spectroscopy as the most proficient and
useful method, although in actuality, atomic fluorescence spectroscopy
has the greatest sensitivity and shows the least effect from interfering
materials. However, the latter method must be held in reserve until the equip-
ment for atomic fluorescence spectroscopy is more readily available.
The titrimetnc methods all have the disadvantage of a loss of sensi-
tivity and accuracy in the presence of other metallic ions. The separations
required before the measurement can be taken cause loss of time because
of increased handling, increased cost because of increased time, and loss
of precision and accuracy because each step has a degree of error associ-
ated with it. Polarographic and ultraviolet spectroscopy lack the sensi-
tivity needed for the trace analyses required in a stationary source
analysis. They also require the removal of interfering ions before the
measurement is made.
19
-------
Thus, until the equipment for atomic fluorescence spectroscopy develops
into a routinely useful analytical tool, we recommend the use of atomic
absorption spectroscopy for the analysis of cadmium (see Appendix 2).
This technique meets the requirements of sensitivity, accuracy and
precision, ease of handling, and availability of equipment without
requiring extensive time or cost.
E. Selenium
According to Stahl94 selenium emissions occur in the refining
of various ores, including copper and lead, and in processes for refining
sulfur residues. Various manufacturing operations may also result in
emissions of selenium related to its use in products such as rectifiers,
photoelectric cells, pigments, and others. Several methods of analysis
*
for measuring these emissions of selenium were considered.
Tabor et al.95 selected a spectrophotometric and fluorometric pro-
cedure for analysis for selenium content of atmospheric particulate matter.
Their method is the basis for the method chosen for selenium and described
in Appendix 2. In this spectrophotometric method, Se(lV) reacts with
2,3-diaminonaphthalene (DAN) in acid solution to give the red-colored
4,5-benzopiazselenol, which is measured at 390 nm. It was found
experimentally that maximum absorption came at 380 nm. The method
described in Appendix 2 for selenium has been appropriately altered.
Other techniques considered were based on polarography,96 flame
emissions spectrometry,97 neutron activation,98 atomic absorption spec-
troscopy, 99-101 isotope dilution,102 fluorometry,95'103-105 catalytic
reduction, 106>107 and a variety of optical spectrophotometric
methods.95,108-111
20
-------
Standards for stationary source emissions of selenium have not been
established by the EPA. The TLV established by the ACGIH is 200 yg/m3.112
In the absence of other guidelines, the method of analysis of
selected should have the capability of measuring concentrations of
selenium at this level.
Of the potential methods described in the literature we chose
the method of Tabor et al.95 because it seemed most nearly to meet the
present need. It has good sensitivity and selectivity. The basis for
the method has been well tested, and standard laboratory equipment can
be used, which is not true of the atomic absorption, catalytic reduction,
or flame emission spectrometry method,
F. Mercury
Information on mercury analysis from various sources was evalu-
ated, and a method using flameless atomic absorption spectroscopy was
selected. The basic method for mercury, which was described by Hatch and
Ott,113 entails converting the mercury to the elemental state and passing
the vapor through a quartz absorption cell of an atomic absorption spectro-
photometer where the mercury vapor concentration is measured. The method
has adequate sensitivity for most purposes. The major problems with meth-
ods of this type are caused by interferences in the sampling procedure,
losses and contamination during sample wortcup, and interference in the
o
measurement step by other materials that absorb at the 2537 A resonance
line of mercury.
The EPA has established an emission standard for stationary emission
sources of mercury of 2300 g (5 pounds) per 24-hour period.114 The sensi-
tivity of the method of analysis will depend on the domjertti'&tiem of
mercury in the source emission. Slight modifications may be required,
depending on the emission level of the source.
21
-------
The determination of mercury in stack gases from nonferrous smelters
represents the most difficult circumstance encountered in source measure-
ment. The high level of S02 in these gases causes serious interference
in sampling procedures. Iodine monochloride (IC1) in Greenburg-Smith
impingers has been used to collect the mercury from the gas stream in
the existing EPA methods of analysis, and this method of collection is
specified in the EPA standards. Unfortunately, IC1 also reacts
with S02 with the result that excessive amounts of S02 destroy all the
IC1, and the mercury vapor is not collected quantitatively. Thus, it was
necessary to modify the approach to the sampling and analysis for mercury
in gases containing high levels of S02, if such a method were to have
general applicability to source measurement.
In the development of a method of analysis for mercury in high S02
stack gases, simplicity in sampling and measurement are important. We
therefore considered the possibility of solid, one-stage scrubbers for
the selective and quantitative collection of mercury. Ideally, this solid
scrubber should be sufficiently selective in the collection of mercury
that it could also be used as the input to a mercury vapor analyzer. For
this purpose it is desirable to have a collection medium that can also
release mercury vapor rapidly and quantitatively when subjected to a
suitable treatment in the mercury measuring apparatus. With these con-
siderations in mind, we evaluated thermodynamic data for a number of pos-
sible reactions of mercury, S02, CO, and C02 with possible solid scrubber
substrates. Some of these reactions and their free energy values (AF° 298)
are given in Table 2. No scrubber substrates were found that quantitatively
collected mercury, and rapidly and quantitatively released it upon appropriate
treatment without interference from S02. Other solid scrubber substrates
should also be examined.
22
-------
Table 2
FREE ENERGY VALUES FOR VARIOUS REACTIONS
Reaction
AF° 298 (kcal)
Hg (g) + |02 (g)
-*
HgO (s)
-21.6
HgO (s) + S02 (g)
Hg (g) + S03 (g)
+ 3.9
HgO (s) + CO (g)
-
Hg (g) + C02 (g)
-39.9
Ag20 (s) + Hg (g)
HgO (s) + 2Ag (s)
-19.0
Ag20 (8) + S02 (g)
S03 (g) + 2Ag (s)
-14.1
Ag20 (s) + CO (g)
C02 (g) + 2Ag (s)
-58.9
2Ag20 (s) + S02 (g)
Ag2S04 (s) + 2Ag (s)
-70.2
Ag20 (a) + C02 (g)
-
Ag2C03 (s)
- 7.6
Co304 (s) + Hg (g)
3CoO (s) + HgO (s)
+ 10.4
Co304 (s) + S02 (g)
S03 (g) + 3CoO (s)
+ 15.3
Co304 (s) + S02 (g)
CoS04 (s) 2CoO (s)
-28.7
Co304 (s) + CO (g)
3CoO (s) + C02 (g)
-29.5
Co304 (s) + CO (g)
—*
C0CO3 (g) + 3CoO (s)
-41.8
CoO (s) + C02 (g)
C0CO3 (s)
-12.3
Ba02 (s) + Hg (g)
-
BaO (s) + HgO (s)
-12.1
Ba02 (s) + S02 (g)
—*
BaS04 (s)
-115.8
BaO (s) + S02 (g)
BaS03 (s)
-64.3
Ba02 (s) + CO (g)
BaC03 (s)
-103.6
BaO (s) + C02 (g)
-
BaC03 (s)
-51.6
23
-------
On the basis of the data summarized in Table 2, it should be possible
to remove S02 from a gas stream and to allow Hg to pass through a column
of Co304 at a temperature of approximately 100 to 200°C. With a packing
of Ag20, however, both Hg and S02 would be collected in the AS20 packing.
The great stabilities of BaS04 and BaS03 would also make it appear feasi-
ble to remove sulfur compounds from a gas stream with a Ba02 solid scrub-
ber without removing any of the Hg at temperatures of 400-500°C.
Before attempting to devise a method of analysis for mercury in
stationary sources, we carried out a limited amount of experimental
laboratory work to develop a method of dealing with mercury in emissions
containing high levels of S02.
Materials tested for use in the scrubber were powdered Pb02, Ba02, and
Ag20. Co304 was not tested. The other materials were tested at various
temperatures to determine their efficiency as S02 trapping agents by introduc-
ing vapors through a septum into a N2 flow stream (l liter/min) that passed
through 5 cm of packing in a glass tube (16 mm o.d.). The gases from the
packing were directed into a detection cell on an atomic absorption spec-
trometer. The 2830 X line from a Pb hollow cathode tube was used to de-
tect S02 gas passing through the system, since S02 absorbs strongly at
this wavelength and the Pb hollow cathode tube was a convenient source.
The transmitted S02 was evidenced by a sharp peak on a strip recorder.
The peak heights were used as a measure of the quantity of gas coming
through the trap, with the value obtained from the gas coming through
24
-------
an unpacked tube representing 100%. The results of these tests are given
in Table 3.
Table 3
S02 REMOVAL AT VARIOUS TEMPERATURES
(Peak Heights - mm)
Pb02
Ba0g
Ag3°
No packing, 25°C
97
73
96
Packing, 25°C
61
51
27
Packing, 100°C
58
46
0
Packing, 200°C
38
34
0
Packing, 400°C
0
0
Table 4 presents the results from a similar test on packing materials,
using mercury vapor instead of S02 gas. In this test a mercury vapor dis-
charge lamp was used to detect the mercury coming through the trap. The
difficulty in maintaining a standard quantity of mercury in the vapor over
liquid mercury, even with agitation, is indicated by the variation found
when no packing was used. The average of the three blanks was 137 mm.
Table 4
Hg REMOVAL AT VARIOUS TEMPERATURES
(Peak Heights - mm)
PbO,
Ba0g
No packing, 25°C
137
127
148
Packing, 25°C
10
124
0
Packing, 100°C
25
121
0
Packing, 200°C
47
143
0
Packing, 300°C
68
—
Hg
Ag,0
at > 230°C
Packing, 400°C 140
25
-------
Both sets of results show that Ag20 readily absorbs S02 and mercury.
The release of the mercury from the packing at 230°C indicates that this
agent could be used in mercury vapor detection. Since Ba02 absorbs S02
but not mercury, Ba02 could be used in a solid scrubber to remove S02
without absorbing any of the mercury vapor. Hie mercury vapor could then
be collected in IC1 solution. Laboratory tests were then carried out
using a Staksamplr ^ to draw laboratory air spiked with mercury through
a Ba02 solid scrubber for S02 and into IC1 solutions in the impingers.
The Ba02 was supported on granular aluminum silicate that was synthesized
in our laboratory. It was found that S02 was quantitatively removed and
mercury was quantitatively passed by the scrubber.
The column packing was prepared by mixing 100 grams of Ba02 with 70 g
of aluminum silicate (40-60 mesh) and heating the mixture for 1 hour at
420°C. The hot mixture was sieved through a 25-mesh sieve. Then an addi-
tional 100 g of Ba02 was mixed with the sieved product. The resulting
mixture was heated 1 hour at 420°C, broken up, and hot sieved. The 25- to
65-mesh fraction was used to pack the S02 scrubber.
Approximately 170 g of the resulting Ba02 aluminum silicate was
packed into a 3.17 cm o.d. x 30.5 cm Pyrex tube equipped on each end
with fittings suitable for connecting it to the Staksamplr® located
just in front of the impingers. The Ba02 tube was held at 420°C in a
3.50 cm i.d. tube furnace. The horizontal mounting of the tube fur-
nace resulted in some channeling along the top of the packing and a
considerable loss in efficiency for removing S02 from the gas stream.
Consequently, S02 broke through long before the total capacity of the
scrubber was used up. This problem could probably be avoided by
mounting the scrubber vertically.
26
-------
In laboratory tests with an air stream containing approximately 5%
S02, it was demonstrated that S02 could be reduced to such a low level
that mercury vapor sampling could be done satisfactorily by the IC1 meth-
od. It was demonstrated that mercury vapor passed through the Ba02 scrub-
ber. This scrubber was tested in one series of field tests.
The field tests were carried out in conjunction with EPA personnel
at a zinc smelter on May 23 and 24, 1972, The purpose of these
tests was to determine whether use of the Ba02 scrubber concept
in the manual IC1 method is, under field conditions, practical for analyz-
ing mercury emissions in stack gases. In this case the S02 concentration
was approximately 7%. A variety of conditions were used in the sampling
train because this was a methods research task and it was not intended
to be used to establish firm data for mercury levels. Our main objective
was to establish a basis for using a solid scrubber to remove S02 from a
stack gas sample before the sample passed through the IC1 scrubbers. This
objective was realized. Additionally, we were able to obtain some data
on mercury levels. The results of these tests are summarized in Table 5.
Test
No.
I
II
III
Date
5/23/72
5/23/72
5/24/72
Table 5
MERCURY CONTENT OF SMELTER FLUE GAS
Volume of
Gas (J m3)
0.064
0.135
0.104
Stack
Temperature
(fF)
455
455
500
Mercury Content (f/g/m3)
Gaseous Particulate Total
23.3
15.5
15.9
10.2
17.3
43.8
33.6
32.8
59.6
27
-------
In Table 5 the particulate mercury levels are based on the mercury content
of the IC1 washings of the probe, filter, and cyclone. The gaseous mer-
cury levels are based on the amount collected in the IC1 solutions in the im-
pingers. The fact that stack temperature was slightly higher than Ba02
scrubber temperature did not create a problem because the mercury vapor
concentrations were well below saturation so that condensation did
not occur as the gas cooled before entering the scrubber.
Although Ba02 decomposes in hot water it is expected that not
enough water vapor will be present to cause a problem at the temperatures
used. The softening of Ba02 at approximately 450°C did not adversely
affect the scrubber, except for shrinkage of the packing and resultant
channeling. Temperatures of at least 400°C are needed for quantitative
removal of S02. The softening of Ba02 does in fact seem to facilitate
the removal of S02.
Test II proved to be the most satisfactory of the three tests. Tests
I and III were interrupted several times for adjustments. Although the
successful use of Ba02 as a solid scrubber for eliminating the S02 inter-
ference in collecting mercury vapor in flue gases was demonstrated, fur-
ther development is needed on several aspects of the system used in these
tests. The experimental setup was crude and will require considerable
improvement before the method can be used routinely in field sampling for
mercury vapor. The Ba02 scrubber heated up considerably during the field
tests, and it will be necessary to design the apparatus so that this exo-
thermic reaction does not result in malfunction of the scrubber before
Ba02 can be used successfully to remove S02 from the gas stream in mer-
cury vapor sampling.
28
-------
A Ba02 scrubber is included in the procedure selected for mercury
analysis (see Appendix 2). We have also included a pyrolysis tube and
omitted the filter from the method so that particulate mercury is converted
to vapor and total mercury is measured as mercury vapor.
29
-------
RESULTS OF LABORATORY AND FIELD TESTING
During Phase II of this study, laboratory and field tests were performed
on the methods of analysis selected in Phase I. Testing in the case of
asbestos and mercury is incomplete, and further development of these methods
may be needed before they are ready for use in measuring source emissions.
A. Asbestos
Laboratory tests were conducted during Phase I.on the method of pre-
paring samples for the electron microscope. The existing methods
for preparing samples were inadequate and needed further development
before they could be incorporated into a method of analysis for asbes-
tos. After several telephone conversations with people active in
this field, we were able to get satisfactory results in the labora-
tory. The procedure that was finally developed and that is presented
in Appendix 2 is based on the work of Frank et al.12 with modifications
suggested by Murchio.13
Field samples were collected at an asbestos mill. Samples were
taken at two locations at the mill. Five samples were taken at the
exhaust of a bag house, shown in Figure 1, and one sample was taken of
the ambient air about 1.5 meters above the ground between two buildings.
The first two samples were taken to get an idea of what the loading
would be for various sample sizes. It was then determined that samples
of 0.01, 0.1, and 1.0 ft3 (0.28, 2.8 and 28 liters) should be taken to
get the desired asbestos loading. These three samples were taken using a
1-inch (2.54-cm) Nuclepore®filter and a probe equipped with a 0.25-inch
(0.63-cm) i.d. nozzle. The samples were all taken from the point indicated
in Figure l)
One sample was taken of 1.2 ft3 (34 liters) of the ambient air about 1.5
meters above ground level. It was collected on a 1-inch (2.54-cm) Nuclepore^
30
-------
BUILDING
HOUSING
BAG HOUSE
BAG HOUSE
EXHAUST
FILTER POSITION
WHILE SAMPLING
op ® oVo
oo o o ,
GROUND
LEVEL
°o-oo
>%„° °. «° ° ° ° ot»°r o °°o%°
oVoooV».v:«?•.:°.v.°0°Q°o°°°°°°6>,t- ¦
qO° o °ft° O °n ° ®Q 0°0 or.9 O _ n 0^.00
O-O'
o o o 0 >
o°0o>o00o ¦
° ° ° O O ° O r
°o o°o°0o ° °c
0 O o O o °.o O
n° °
fo
o o
O 0 0 O
o o o '
w ° ° rt °- O O o
0*° ° o o
° O O
o „
o o o 0 o ° o ,® « 9X O - 0 °° O o °
I.V . o . °°„
° O0 o'' ° o° 0°ao 0»0 0O„ 9 „"•» ° ° O® 6« 0 O 9 °° O 0 °o O ° OO0„ O ' O O I» «» 0„ O O OD „ C
- „ „
> ° 0 o o ° o ° ° »'o 0 0 o o ° ° "
° ° O 0° 9 ° ° °0 O °a Oo° ° '
°0oo ri o oQo ft 0 °ft° o ° °
°^o° °o°0> o °ooQo00oOo 2
00 c
O o o
• 0 O 0
° o o :
°0°0°0°0°0°0 0=0$
0 o o Q o 0 °o o.o
c °oO°°f o
°2° °o 0 °°
o o
O O O c
V? ?o° o
jO0
, o c
-O o
o o
OOOO oCo
°oV °°° o"tto o0o.o0„o"0 o 0°0 / ?;M 0
° ° ° O ° o ° 0°0_oo o o_° ° ol
SA-1374-6
0 60° a O O 6 o »o°o-9 °no°
5° o O o.o o°_ h °o 0 °oO oo0
O o o o
FIGURE 1 ASBESTOS SAMPLING LOCATION AT BAG HOUSE EXHAUST
[FLOW = 40,000 cfm <18.9 m3/sec)]
31
-------
filter in a holder with a 1-inch (2.54-cm) opening.
Figure 2 is a photomicrograph of a typical grid opening for the 0.1-
ft3 (2.8-liter) sample taken from the bag house exhaust and corresponds to grid
opening number 2 in Table 6. The fine structure in the background of the
photomicrograph is caused by filter fragments. One of the difficulties
with this method is the incompleteness of the dissolution of the filter.
An independent method of sample collection and processing gave evidence
that many of the smaller particles were lost.
Counts were made of the fibrous asbestos particles in Figure 2
and in other grid openings from the bag house exhaust and ambient air
samples. The results are listed in Table 6. The number of asbestos
particles per electron microscopic field were determined for these
two samples from the data in Table 6. The bag house exhaust sample
contained approximately 7 asbestos particles per field (average 47
particles/grid opening, 7 fields/grid opening). The ambient air
sample contained approximately 12 asbestos particles per field (85
particles/grid opening). It was determined from these data and from
electronmicrographs of the samples that 5 to 50 particles per field
in all size categories would be a reasonable amount of asbestos to collect.
The total number of asbestos particles to be collected on a filter
with a 20-mm effective diameter was calculated to be in the range of
630,000 to 6,300,000 (field ~ 50 on a side). The range of the
method of analysis for asbestos in Appendix 2 is based on this number
of particles per sample. The concentrations of the sources were also
calculated. The concentrations in the bag house exhaust sample and
ambient air samples were 9 million and 1 million fibers per cubic toot
(3.2 x 105 and 3.5 x 104 fibers per liter), respectively. This represents
all particle size categories.
32
-------
-------
Table 6
Particle Size
> 10 jU long
Aspect ratio >3
Aspect ratio <3
5-10 u long
Aspect ratio >3
Aspect ratio <3
2-5 y, long
Aspect ratio >3
Aspect ratio <3
0.5-2 u long
Aspect ratio >3
Aspect ratio <3
COUNTS OF ASBESTOS PARTICLES IN
SAMPLES COLLECTED AT ASBESTOS MILL
Ambient
Bag House Exhaust Air
Grid 1 Grid 2 Grid 3 Grid 4 Grid 5 Grid 1
8
11
7
5
4
6
0
1
4
17
6
6
5
9
0
0
10
17
4
10
5
5
0
1
6
11
6
10
4
5
0
1
8
11
5
11
5
6
0
6
9
31
12
15
12
7
The electron microscopic method of analysis for asbestos has a
major advantage over optical methods currently being used in that it is
possible to positively identify fibrous asbestos material by direct
observation with the electron microscope. The fibrous tubes of
chrysotile asbestos can be clearly seen. For absolute identification
electron diffraction should be used for each particle. With the optica
method, however, the fibrous tubes are not discernible and aspect
ratios must be used to determine whether a particle is fibrous. If an
observed particle has an aspect ratio greater than 3 (length/width) it
is considered asbestos. It can be seen in Table 6 that about half of
the asbestos particles counted have aspect ratios less than 3. . These
asbestos particles with aspect ratios less than 3 are bundles of
asbestos fibers as can be seen in Figure 2. Thus, the optical method
of analysis of asbestos should give low results.
34
-------
For standardization of the method, samples should be taken of an
atmosphere or a gas stream of known concentration, and then the amount
of asbestos collected and the volume of the sample taken checked
against the known source concentration. In some cases nonisokinetic
samples must be taken (such as from ore piles, tailings, dumps, and
roads),f and the accuracy of this method of sampling asbestos should
be tested along with isokinetic sampling methods.
Sampling probes should present the filter directly to the source,
avoiding nozzles that present an asbestos retention problem. If
the diameter of the nozzle is smaller than the area of the filter, it may
cause an uneven distribution of asbestos because of expansion just before
the filter.
B. Beryllium
Laboratory tests were conducted on the method of analysis selected
for beryllium. The method was tested in the 0-5 and 0-0.5 jig Be/ml ranges
using standard and spiked samples. A standard consists of an aliquot of a
solution of known beryllium concentration. A spiked sample consists
of a filter and impinger acid solutions to which an aliquot of a solution
of known beryllium concentration has been added. The results are shown
in Table 7.
A standard curve was drawn and sample concentrations were determined.
We then calculated the average relative deviation of these sample
concentrations (determined from the standard curve) from the true value.
This is defined as the accuracy of the analytical method. For the 0.5-5 /jg
Be/ml range, the accuracy was + 6$. Below 0.5 jig Be/ml, the accuracy was
± 20$. The 0.5-5 /Ltg Be/ml range corresponds to a source containing
0.03-0.30 /ig/ft3 (l-10(ig/m3) for a sample of 100 ft3 (3 m3) . The average
relative deviation from the mean was calculated using the same values
obtained from the standard curve. This is defined as the precision of
the analytical method. The precision of 0.5-5 /ig Be/ml range was + 4$;
below 0.5 jxg Be/ml, it was + 11$.
35
-------
Table 7
LABORATORY MEASUREMENTS OF BERYLLIUM SAMPLES
Concentration Atomic Absorption Reading
(Ug Be/ml) Standard Sample (Spiked)
0.05 0.036 0.033
0.033
0.10 0.054 0.025
0.043
0.20 0.092 0.087
0.077
0.50 0.260 0.218
0.219 0.211
0.169
0.227
Absorbance (Optical Density)
Standard Sample (Spiked)
0.5 0.050 0.051
0.058 0.054
0.043
0.047
1.0 0.099 0.094
0.097
2.0 0.195 0.188
5.0 0.453 0.458
36
-------
•V
The method of masking interferants with K was tested. A solution with
2+ +
5.0 jig Be /ml and 10,000 fig K /ml was prepared.
, 2+ 2+ 4+
Another solution was prepared containing 4,000 fig/ml each of Pb , Cd , Se ,
2+ + , 2+ ,
and Hg as interferants, plus 10,000 K /ml and 5.0 jUg Be /ml. These
cations were all added as sulfate, chloride, or nitrate, salts, except for
2+
Be , which was prepared from a commercial standard, of unknown anion content.
During the attempt to measure the beryllium concentration on the atomic absorp-
tion spectrophotometer, the aspirator clogged and no reliable readings were
obtained. Precipitates were noted in both solutions. The precipitate in the K+
2+
and Be solution was probably KC104, caused by not completely evaporat-
ing to dryness the HC104 and H2S04 that were added to oxidize Be. In
the other solution, the precipitate was either HC104 or PbS04 or a com-
bination of the two. This phase of the beryllium method should be
retested.
Field sampling for beryllium was conducted at a beryllium machining
facility. One sample was taken from each of two locations atop the
roof of the building containing a beryllium machine shop. Sampling data
and calculations are presented in Section F of this report.
The first sample was taken from a stack that exhausts into
the atmosphere. The stack and the system it is part of is shown in
Figure 3. This stack meets the EPA criteria for a suitable site.118
The stack was traversed along one diameter only, since the diameter at
90° would have created a problem of supporting the impinger box and
probe. Two traversing points were used.
A hexane trap in an acetone/dry ice bath was used in place of the
silica gel trap described in the SRI Method of Analysis #2 in Appendix
2. There has been some evidence of the existence of volatile beryllium
compounds, and this trap was used to verify that all the beryllium was
caught in the filter and impingers.116
37
-------
ir
r
10"
15'
BAG^
house'
SAMPLING PORT
V
MACHINE
SHOP
BERYLLIUM FROM
| MACHINING
EQUIPMENT
SA-1374-3
FIGURE 3 FIRST BERYLLIUM SAMPLING LOCATION
38
-------
FILTER
bank'
SAMPLING PORT
V
¥
\ i
1
16-1/2"
BERYLLIUM
MACHINE
SHOP
BERYLLIUM
FROM |
MACHINING '
EQUIPMENT
•BAG HOUSE
V
SA-1374-4
FIGURE 4 SECOND BERYLLIUM SAMPLING LOCATION
39
-------
Since little beryllium was found in the first sampling location, another
location was tried that was expected to have more beryllium. This second
sampling site is shown in Figure 4.
The second sample (Be #2) was collected with the conventional
sampling train described in SRI Method of Analysis #2. The hexane
impinger was not used because of ice clogging problems experienced
with it in Be #1. No traversing of the duct was performed because the
positive pressure in the duct would have presented a health hazard to the
personnel moving the probe. The nozzle was placed in the center of the
duct. The sampling port could not be easily placed at a point that
would meet the EPA criteria of sample port location,115 so the location
in Figure 4 was chosen.
The amounts of Be collected at both locations were less than 1 fxg,
as shown in Table 8.
Table 8
MEASUREMENTS OF BERYLLIUM FIELD SAMPLES
Total Be Sampling
Sample Collected (us) Time (hr)
Be #1 0.18 3
(minus hexane)
impinger
Be #1 0 3
(hexane impinger)
Be #2 0.22 4
The concentration of the solutions prepared from the samples taken
(~0.02 ^g/ml for both nonhexane samples) were below the lowest standard
40
-------
(0.05 ^g/ml). However, this concentration of Be is measurable since
it is an order of magnitude above the detection limit of the atomic
absorbtion spectrophotometer (0.002 jig/ml).
Although no beryllium was detected in the hexane irapinger of Be #1,
this does not conclusively demonstrate the efficiency of the filter and acid
impingers because the levels of beryllium were so low. No attempt was
made to evaluate the efficiency of individual parts of the sampling
train because of the small amounts of beryllium collected.
More detailed data on the two samples described above , along with the
calculations used to arrive at the figures presented* can be found in
Section IV F.
C. Lead and Cadmium
Since these two pollutants were field tested at the same site they
will be discussed together, following the laboratory test results.
During laboratory tests on lead it was found that the absorbances
of the standards (an aliquot of known beryllium concentration) and the
spiked samples (a filter, acid impinger solutions, and a known amount of
beryllium) had different slopes when plotted on a graph. The data
obtained is presented in the following tabulation.
Concentration Absorbance
(tig Pb/ml Standards Samples (Spiked)
1
5
6
10
20
30
50
0.005
0.027
41
-------
The slope of the standards curve is calculated to be 0.0057 optical density
units/jug Pb/ml. The data for the spiked samples yields a slope of 0.0038
optical density units/|jg Pb/ml. The EPA project officer suggested that these
differences between standards and spiked filter samples might be caused by
matrix effects resulting from different nitric acid concentrations.
A second test of this method was conducted. In this test, standards
and spiked filter samples were prepared using the same procedure for both
so that they contained the same concentration of nitric acid. The results
of that test are shown below.
Concentration Absorbance
(jUg Pb/ml) Standards Samples (Spiked)
5 0.033 0.030
10 0.065
15 0.097 0.095
20 0.125
The data from these standards and spiked samples correlate well. The analytical
method was appropriately changed so that standards and samples are pre-
pared in a similar manner.
The opportunity to use the lead analytical method for the analysis
of several urban air samples arose during this reporting period. Al-
though this method was not specifically designed for this type of sample,
the project team felt that it could be successfully applied. The Atmos-
pheric Sciences Laboratory at SRI provided the samples and funds for this
analysis.
The samples were collected on glass fiber filters similar to those
used to collect particulate in most of the methods in this project. The
filters were analyzed by means of the analytical method developed for
lead, except that no impinger solutions were used. The filters were low-
temperature ashed and then extracted with dilute nitric acid. The extract
was concentrated, diluted to the mark in a 10-ml volumetric flask,
and then analyzed.
42
-------
Both normal and scale expanded atomic absorption measurements were
used to analyze the samples. The data obtained are presented in Table 9.
The correlation between the amount of particulate on the five filters
with the heaviest particulate accumulation and the amount of lead detected
was noted.
In the analytical method for cadmium it was noted that the concen-
trations of the standards were low by a factor of ten. Appropriate
changes were made in the procedure to correct the concentrations.
The volume of solution into which the sample is taken for analysis
by atomic absorption spectroscopy was increased from 5 ml to 10 ml
so that more than one analysis could be made of the sample, if necessary.
After these changes were made, the analytical method was laboratory
tested. The results are presented below.
Concentration Absorbance
(lig Cd/ml) Standard Sample (Spiked)
0.5 0.044 0.046
1.0 ti.083 0.083
1.5 0.116
2.0 0.152 0.150
The field tests for lead and cadmium were conducted at a municipal
incinerator in Dade County, Florida. The sampling location, as. shown in
Figure 5, was near the exit of the stack used to emit combustion products
to the atmosphere.
Four samples were taken;: two 2-hour samples and two 4-hour samples.
Only half the diameter was traversed since only a 1.5-meter probe was
available. Six traverse points were located on a diameter. The ports
facing south and east were sampled during Pb-Cd §1. During the
rest of the sampling (Pb-Cd $2-4)>only the south port was sampled.
Access was limited to other ports because another sampling team was on
the stack. Sampling data and calculations are presented in Section F of
this report.
43
-------
Table 9
LABORATORY MEASUREMENTS OF LEAD SAMPLES
Sample
Percent
Absorption
(x 5)
Absorbance
(O.D.)
Concentration
(/ig Pb/ml) of
1/2 filter
in 10 ml
/ig Pb in
Whole
Filter*
Weight of
Particulate
on Filter
fug)
Water blank 0.000
1.0 US Pb/ml standard 0.056
2.5 yg Pb/ml standard 0.132
5.0 fig Pb/ml standard 0.268
1A 0.031
IB 0.012
2B 0.061
ID 0.152
2C 0.253
2D 0.049
2E 0.030
2F (blank filter) 0.009
0.58
0.22
1.14
2.83
4.71
0.91
0.56
10.6
4.4
22.8
56.6
94.2
18.2
11.2
1198
146:
15 0(
397c
4068
88e
41£
Water blank
5.0 jUg Pb/ml standard
10.0 fig Pb/ml standard
15.0 fig Pb/ml standard
20.0 fj,g Pb/ml standard
2A
1C
0.002
0.024
0.046
0.067
0.090
0.034
7.3
9.1
146
182
5599
8041
0.042
*0btained by multiplying previous column by 20.
' / /
44
-------
SAMPLING.
PORTS*
SAMPLING
PLATFORM
80'
SAMPLING
PORTS
STACK
SAMPLING
PLATFORM
SIDE VIEW OF STACK
TOP VIEW OF STACK
SA-1374-5
FIGURE 5 LEAD AND CADMIUM SAMPLING SITE
45
-------
The sampling train was divided into four components: (l) the probe
and cyclone; (2) the filter; (3) the first impinger; and (4) the second
and third impingers. Each component was analyzed for both lead and cadmium.
The results of these analyses are presented in Table 10.
Table 10
MEASUREMENTS OF LEAD AND CADMIUM FIELD SAMPLES
Sampling Train Component
Probe and 1st Impinger 2nd & 3rd
Sample Cyclone fotg) Filter (yg) (jig) Impingers (ug)
Pb
#1
2145
1709
51
0
Pb
#2
1525
2629
1
2
Pb
#3
1405
3499
37
6
Pb
#4
2545
1419
5
7
Cd
#1
59
59
9
0
Cd
#2
52
59
0
0
Cd
#3
90
137
1
1
Cd
#4
90
120
0
0
In all cases, except for in Cd #1, 99$ or more of the lead or cadmium
collected was found in the probe, cyclone, and filter. This indicates that
the lead and cadmium were in a particulate form and that no significant
volatile lead or cadmium compounds were present. If one were certain
that the lead or cadmium in a source of interest is in particulate
form, this analytical method could be used without the acid impingers.
No correlations can be made between the amounts of lead and cadmium found
in the four samples, since the conditions under which the incineration
took place may have changed from sample to sample and the amount of lead and
46
-------
cadmium in the garbage may also have varied.
Some contribution to the amounts of lead and cadmium found may have come
from the refractory material on the inside wall of the stack. A portion
of this material was analyzed and was found to contain about 5 j/g Pb/mg
of refractory material and 0.1 fig Cd/mg of refractory.material. This lead
and cadmium may be from the refractory itself, or it may be due to contami-
nation.
The methods of analysis for lead and cadmium seem to have worked
well, and more than enough lead and cadmium were collected from this
particular source to be analyzed. The solutions made up from the
material collected in the probe and cyclone and that collected on the
filter had to be diluted tenfold for analysis. The accuracy and
precision of the analytical method for lead in the 5-20 fj,g/ml range were
calculated to be ±3$ and ±2$, respectively, and below 5 |Ug/ml, ±4$ and ±3$,
respectively. The 5-20 |Ug Pb/ml range corresponds to 0.6-2 ^g/ft3 (20-70
jlg/m3) for a 100 ft3 (3 m3) sample. The accuracy and precision of the
analytical method for cadmium are ±3$ and ±3$, respectively, for the 0.5
to 2.0 jUg/ml range and ±4$ and ±3$, respectively, for concentrations below
0.5 fxg/ml. Not enough data were collected to determine the accuracy or
precision of the total method including sampling. The 0.5 to 2 jug/ml range
corresponds to a 100 ft3 (3m3) sample taken from an emission source containing
0.05 to 0.2 ^ig/ft3 (2 to 7 J/g/m3).
D. Selenium
Several problems were encountered in laboratory tests of the selenium
analytical method. It was found that the wavelength at which the absorb-
ance of 4,5-benzopiazselenol (the reaction product of 2,3-diaminonaphtha-
lene and Se (IV)) is to be measured was reported incorrectly in the
literature at 390 nm. The absorbance maximum was experimentally found to be
at 380 nm. This can be seen in Table 11.
47
-------
Table 11
ABSORBANCE SPECTRUM OF A SOLUTION OF
4,5-BENZOPIAZSELENOL IN TOLUENE
Wavelength Optical
(mil) Density
370 0.65
375 0.57
380 1.10
385 0.51
390 0.12
395 0.04
An interference filter was used to check the accuracy of the spectro-
photometer. A filter with a maximum transmission at 381.4 nm gave a
maximum transmission at 382.2 nm on the spectrophotometer.
Measurements of standard and spiked filter samples were made
at 380 nm and are presented in Table 12.
Table 12
LABORATORY MEASUREMENTS OF SELENIUM
Concentration Absorbances
(lig Se/50 ml toluene) Standard Sample
10 0.15
20 - 0.19
50 0.29
100 0.49 0.64
150 0.83 0.91
200 1.10
48
-------
The accuracy and precision calculated for the analytical method alone are
±14$ and ±9$, respectively, for 20-200 jtg Se/50 ml toluene. The 20-200 fig
Se/ml toluene range corresponds to sampling 100 ft3 (3 m3) of an
emission source with a concentration in its stack gases of 0.2-2 ^g/ft3
(7-70 Jig/m3) .
No field sampling of the method of analysis for selenium was conducted
because of a change in the scope of work, which no longer required field
testing for selenium.
E. Mercury
Much of the method of analysis for mercury in Appendix 2 was newly
formulated during this study. The laboratory and field testing was
performed in Phase I in support of this development. It was therefore
discussed earlier in Section III F of this report.
The collection system, including the Ba02 scrubber, has been
proved in use for small samples. Development of a Ba02 scrubber that will
handle larger samples containing S02 is needed. Also, testing of the
collection system with the pyrolysis tube is needed.
The analytical method was tested successfully and has an accuracy
of ±3$ where the total amount of collected mercury is in the range of
45-665 ng. This accuracy is based on the analysis of Hg standards.
Insufficient data were collected to establish the precision. Analytical
method or the accuracy and precision of the total method including sampling.
F. Data and Calculations for Lead, Cadmium, and Beryllium Field Samples
The sampling data obtained for lead, cadmium, and beryllium are given
in Table 13. This is followed by an explanation of the isokinetic sampling
calculations used to derive these data and the definitions of the terms
used in the calculations.
49
-------
Table 13
LEAD, CADMIUM, AND BERYLLIUM SAMPLING DATA
AH
Tm °F
Tm °R
Pb
Vm
Vm
std
Vw
Vw
gas
% M
Md
% co2
% Oa
% CO
MWd
MW
t3 °r
Cp
p3
Vg
Qs
Qa
Tt
D
n
%1
Pb-Cd No. 1
6/11/73
0.95
86.6
546.6
30.00
64.252
62.562
231.7
10.983
14.93
0.851
3
17
0
29.16
27.50
860
0.85
30.00
2675
99744
189,607
120
0.25
108.4
Pb-Cd No. 2 Pb-Cd No. 3 Pb-Cd No. 4
6/12/73
1.11
90.4
550.4
30.05
66.397
64,334
253.2
12.002
15.722
0.843
3
17
0
29.16
27.41
860
0.85
30.05
3041
112,460
215,520
120
0.25
98.8
6/13/73
0.99
93,8
553.8
30.26
130.22
126.24
396.8
18.808
12.967
0.870
3
17
0
29.16
27.71
860
0.85
30.26
2836
109,007
201,016
240
0.25
100.0
6/14/73
1.00
102
562
30.28
132.977
127.209
474.5
22.491
15.024
0.850
3
17
0
29.16
27.48
860
0.85
30.28
2941
110,502
208,429
240
0.25
99.4
Be No. 1
9/19/73
3.6
105
565
30.05
179.643
70.96
25
1.185
0.69
0.99
0
20
0
28.8
28.7
542
0.85
30.08
3025
3147
3233
180
0.25
94.4
Be No. 2
9/21/73
2.6
110
570
30.20
208.982
197.28
49.6
2.35
1.18
0.99
0
20
0
28.8
28.7
545
0.85
30.70
2545
3733
3779
240
0.25
95.6
50
-------
ISOKINETIC SAMPLING CALCULATIONS
1. Volume of dry gas sampled at standard conditions, DSCF
17.7 x V (P + m)
V m v b —t
m = 13.6
std :
(T + 460)
m
2. Volume of water vapor at standard conditions, SCF
V
w = 0.0474 x V
gas w
3. Percent moisture in stack gas
100 x V
w
$ M = gas
V + V
m w
std gas
4. Mole fraction of dry gas
M, = 100 - % M
d '
100
5. Molecular weight of dry stack gas
44 32 r
md = (^02 X W + X W + [_(^° + ^
6. Molecular weight of wet stack gas
MW=MW xM + 18 (1 - M )
d d v d'
7. Stack gas velocity at stack conditions, fpm
V = 5128.8 x C x
, r i ]
y^s x ^Ts + 400^ LP x m J
1/2
51
-------
8. Stack gas volumetric flow rate at standard conditions, DSCFM
0.123 x V x A x M x P
s s d s
Q =
s (T + 400)
9. Stack gas volumetric flow rate at stack conditions, ACFM
0.05645 x Q (T + 480)
s s
Q =
a P x M
10. Percent isokinetic
1032 x (T + 460) x V
s m
_ std
~ V jTt Fp x~M x (D )'z
s t s d n
52
-------
DEFINITION
OF TERMS
Symbol
Unit
Description
AH
in. H20
Orifice meter differential pressure
AH
in. H20
Average orifice meter differential
T in
m
°F
Temperature, gas meter, inlet
T
m
out
°F
Temperature, gas meter, outlet
a
number of
sets of data
T °F
m
T °R
m
°F
°R
Average gas meter temp., (°F)
Average gas meter temp., "R"
P
b
in. Hg
Barometric pressure, absolute
V
m
cu ft
Volume gas sampled at the meter
V
m
std
cu ft
Volume gas sampled, STP
V
w
ml
Volume of water collected, total
V
w
gas
ft3
Volume of water converted to gas at Sr
^ M
$
°jo moisture by volume stack gas
M
d
dimensionless
Mole fraction, dry gas
¦4 CO,
$
13 C02 stack gas, dry basis, by volume
-i o2
%
°jo 02 stack gas, dry basis, by volume
4 co + $ n2
1°
-------
Symbol
A
s
T °R
s
Q
s
Q
a
T
t
D
n
$1
From
inches
°F
°F
°C
ft3
ft/min
DEFINITION OF TERMS
Unit Description
in.2 Area of stack at sampling point
°R Average stack temperature, °R
ft3/min Stack gas flow rate, STPD, DSCFM
ft3/min Stack gas flow rate, stack cond.
minutes Time of test
inches Diameter of probe tip
$ $ Isokinetic
CONVERSION TABLE
To Operation
millimeters 25.4 (inches)
°C 5/9 (°F - 32)
°R °F + 460
°K °C + 273
liters 28.3 (ft3)
cm/sec 0.508 (ft/min)
54
-------
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50. A. A. Koch, atomic absorption specialist, private communication,
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58
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55. U.S. Public Health Service, "Air Pollution Measurements of the
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p. 11.
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59. K. Fuwa and B. L. Vallee, "The Physical Basis of Analytical Atomic
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60. B. M. Gatehouse and J. B. Willis, "Performance of a Simple Atomic
Absorption Spectrophotometer," Spectrochim. Acta, 17, 710-718 (1961).
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Zinc by Atomic Absorption Spectroscopy," Anal. Chim. Acta, 37, 20-26
(1967).
62. J. P. Riley and D. Taylor, "Atomization with Heated Air for Sensitiv-
ity Enhancement in Atomic Absorption Spectrophotometry," Anal. Chim.
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Traces of Metal Ions," Anal. Chim. Acta, 44, 301-307 (1969).
64. B. Pulido, K. Fuwa, and B. L. Vallee, "Determination of Cadmium in
Biological Materials by Atomic Absorption Spectrophotometry," Anal.
Biochem., 14, 393-404 (1966).
65. M. P. Bratzel, Jr., R. M. Dagnall, and J. D. Winefordner, "A Com-
parative Study of Premixed and Turbulent Air-Hydrogen Flames in
Atomic Fluorescence Spectrometry," Anal. Chem., 41, 713-718 (1969).
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59
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67
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M. P. Bratzel, Jr., J. M. Mansfield, Jr., and J. D. Winefordner,
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M. S. Cresser and T. S. West, "Some Interference Studies in Atomic
Fluorescence Spectroscopy with a Continuum Source," Spectrochim.
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etry, " AnajL1_£hjjii:_A£U, 36, 269-277 (1966).
R. M. Dagnall, T. S. West, and P. Young, "Determination of Cadmium
by Atomic Fluorescence and Atomic Absorption Spectrophotometry,"
Talanta, 13, 803-808 (1966).
R. S. Hobbs et al., "Spectroscopy in Separated Flames: IV Applica-
tion of the Nitrogen-Separated Air-Acetylene Flame in Flame-Emission
and Atomic-Fluorescence Spectroscopy," Talanta, 15, 997-1007 (1968).
J. M. Mansfield, J. D. Winefordner, and C. Veillon, "High Sensitivity
Determination of Zinc, Cadmium, Mercury, Thallium, Gallium, and In-
dium by Atomic Fluorescence Flame Spectrometry," Anal. Chem., 37,
1049-1051 (1965).
N. Omenetto and G. Rossi, "Atomic Fluorescence Flame Spectrometry
Using a Mercury Line Source," Anal. Chim. Acta, 40, 195-200 (1968).
C. Veillon et al., "Use of a Continuous Source in Flame Fluorescence
Spectrometry," Anal. Chem., 38, 204-208 (1966).
J. D. Winefordner and R. A. Staab, "Study of Experimental Parameters
in Atomic Fluorescence Flame Spectrometry," Anal. Chem., 30, 1967-
1969 (1964).
J. D. Winefordner and T. J. Vickers, "Calculation of the Limit of
Detectability in Atomic Absorption Flame Spectrometry," Anal. Chem.,
36, 1947-1954 (1964).
J, D. Winefordner and T. J. Vickers, "Calculation of the Limit of
Detectability in Atomic Emission Flame Spectrometry," Anal. Chem.,
36, 1939-1947 (1964).
K. Zacha and Winefordner, "Use of an Argon-Hydrogen-Entrained Air
Flame with a Total-Consumption Aspirator-Burner and a Simple Instru-
mental System in Flame Emission Spectrometry for Trace Metal Deter-
mination, " A£a2_;_Cheni., 38, 1537-1539 (1966).
60
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79
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85
86
87
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91
C. Auerbach et al.f "Incremental Approach to Derivative Polarography,"
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W. F. Kinard, R. H. Philp, and R. C. Propst, "Analytical Applications
of Kalousek Polarography," Anal. Chem., 39, 1556-1562 (1967).
M. Kodama and T. Noda, "Application of a Mercury-Coated Platinum
Electrode to the A.C. Stripping Analysis of a Trace Amount of Metal
Ions," Bull. Chem. Soc. Japan, 42, 2699-2701 (1969).
C. K. Mann "Stationary Electrode Polarography with a Staircase Volt-
age Sweep," Anal. Chem., 33, 1484-1491 (1961).
H. I. Shalgosky and J. Watling, "High Precision Comparative Polarog-
raphy , " AnalJ_Chm;_Ac1^, 26, 66-74 (1962).
R. Belcher, B. Crossland, and T. R. Fennell, "Photometric Titration
of Small Quantities of Metals with Ethylenediaminetetra-Acetic Acid,"
Talanta, 16, 1335-1339 (1969).
R. T. Campbell and C. N. Reilley, "Chelometric Titrations with Am-
perometric End-Point Detection," Talanta, 9, 153-167 (1962).
S. Hanamura, "An I-Q Recorder and Its Application to Rapid Coulo-
metric Analysis and Micro-Coulometry," Talanta, 9, 901-915 (1962).
G. F. Kirkbright and W. I. Stephen, "3,3'-Dehydroxybenzidine-
N,N,N ,N -Tetraacetic Acid as a Metallofluorescent Indicator in
EDTA Titrations," Anal. Chim. Acta, 28, 327-330 (1963).
R. E. Monk and K. C. Steed, "Microchemical Methods in Radiochemical
Analysis: II Determinations of Chemical Yields by Micro-Coulometry,"
Anal. Chim. Acta, 26, 305-315 (1962).
R. C. Schonebaum and E. Breekland, "Possibility of Automation of
Potentiometric ADTA Titrations," Talanta, 11, 659-661 (1964).
O. Yamauchi, H. Tanaka, and T. Uno, "Studies on Imidazole Deriva-
tives as Chelating Agents," Talanta, 15, 459-474 (1968).
B. E. Saltzman, "Colorimetric Microdetermination of Cadmium with
Dithizone," Anal. Chem., 25, 493-495 (1953).
61
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92
93
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97
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Donalson, T. Dubois, and R. E. Kupel, Health Lab. Sci., 7, 96 (1970).
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and selenium dioxide in the air of workshops, Z. Ges. Hyg. (Berlin), .
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R. Dams, J. A. Robins, K. A. Rahn, and J. W. Winchester, "Nonde-
structive neutron activation analysis of air pollution particulates,"
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8, 34 (1969).
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J. H. Watkinson, Anal. Chem., _32, 981 (1960).
P. W. West, and T. V. Ramakrishna, "A Catalytic Method for Determining
Traces of Seleniun, Anal. Chem., 40, 966-68 (1968).
T. Kawashima and M. Tanaka, Anal. Chim. Acta, 40, 137 (1968).
R. L. Osburn, Anal. Chem., 43, 594 (1971).
62
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109. P. W. West, and Ch. Cimerman, "Microdetermination of Selenium with
3,3'-Diaminobenzidine by the Ring Oven Technique and its Application
to Air Pollution Studies," Anal. Chem., 3(3, No. 10, 2013-16 (1964).
110. L. S. Alekseeva, Gig. Samit., 35, 59 (1970).
111. K. L. Cheng, Anal. Chem., 28, 1738 (1956).
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of the American Conference of Governmental Industrial Hygienists,
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114. Federal Register, Vol. 38, No. 66, pp. 8831-32 (April 6, 1973).
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116. M. S. Black and R. E. Sievers, Anal. Chem., 45, 1773 (1973).
63
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Appendix 1
BACKGROUND INFORMATION
Introduction
Although the objective of Phase I of the study was to evaluate and
select methods of analysis for the polluntants under consideration, infor-
mation on the toxic effects of these pollutants was also gathered. This
material was not directly used in the selection of methods of analysis,
but is presented here as general background information.
Asbestos
Since the background information concerning the toxic effects of
asbestos was necessarily used in the explanation of selecting a method,
it will not be repeated here. Refer to Section IIIA of this report.
Beryllium
According to White and Burke,1 beryllium compounds have relatively
recently become known as hazardous industrial materials and are now con-
sidered to be among the most hazardous and toxic of the nonradioactive
substances being used in industry today. Before 1943 the diseases caused
by these compounds were attributed to some other agent, usually fluorides.
Although overwhelming evidence for the toxicity of beryllium compounds
was accumulated, the toxicologists were reluctant to accept it because
they found the data confusing. In 1948 the U.S. Atomic Energy Commission
Beryllium Advisory Board finally took measures to reduce atmospheric
1-1
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contamination by recommending the following standards as safe exposure
levels:
• The in-plant atmosphere should not exceed 2 jig/m3 averaged
over an 8-hour day.
• The concentration should not exceed 25 /ig/m3 for any period,
regardless of length of duration.
• The atmosphere in the area surrounding the plant should not
exceed 0.01 /i/m3 .
This action caused many industrial plants to build in the necessary
safety equipment, while others such as the fluorescent lamp industry
discontinued the use of beryllium compounds by general agreement.
Although beryllium is not dangerous in a solid form, it is danger-
ous in the form of finely divided particles, i.e., as a powder, vapor,
or solution. Thus machining transforms a harmless bar of metal into a
toxic material. Beryllium compounds that are appreciably soluble, such
as beryllium nitrate, sulfate, fluoride, bromide, and chloride, are par-
ticularly active. The temperature at which the beryllium compound is
calcined is closely related to the toxic effect. Oxides produced at
high temperatures have a larger crystallite size, lower specific sur-
face, and lower toxicity than oxides produced at low temperatures.2
Thus the effects of beryllium poisoning are related to both the chemical
nature and the physical characteristics of the beryllium compound.
The extraordinary toxicity of beryllium is illustrated by the occur-
rence of berylliosis among residents in the vicinity of plants in which
beryllium is processed. In one area, 16 cases, including 5 fatalities,
occurred within three-fourths of a mile of a plant producing beryllium
from the ore.3 An analysis of the atmosphere in this area showed concen-
trations of beryllium to be less than 1 fjLg/m? ; concentrations in 30 other
areas (900 samples) were found to be 0.0001 to 0.0003 jlg/m3. It is to be
noted that although lead, arsenic, and mercury pollution have a large
1-2
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capacity for causing disease or death among workers, no cases of com-
munity poisoning are known.
More complete discussions of the toxic effects of beryllium are
provided by White and Burke1-3 and Gafafer.4
Lead
Most knowledge of lead inhalation toxicity comes from industrial ex-
perience where the atmospheric TLV for exposed workers recommended by the
American Conference of Government Industrial Hygienists is 200 JZg/m3.5>6
This value is more than 100 times the average ambient concentration in
the United States. Inorganic lead at the highest airborne concentrations
has not been reported as a cause of acute lead reactions. Nevertheless,
the effects of lead on man in the region of concentrations less than the
TLV value have been investigated by Tepper and Pfitzer at the Kettering
Laboratory.7 Their preliminary studies show no effects at or below a
level of 10 Jig/m3 of lead in air.
After reviewing the material covered in the Air Quality Monographs8
and elsewhere, the American Industrial Hygiene Association in 1969 rec-
ommended an ambient air quality value for lead of 10 ^lg/m3 average over
a period of 30 days. This value is only a recommendation, since the
effects of lead at lower concentrations are not fully understood.
The toxicity of lead has been reviewed thoroughly by Haley.9 The
reader is referred to this publication for more information on this
subject.
Cadmium
Cadmium is considered to be a toxic material. There is some evi-
dence, inconclusive however, that cadmium in concentrations found in the
atmosphere is related to cardiovascular disease and cancer.10
1-3
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The use of cadmium materials has increased steadily since 1900. It
is now being used extensively in some 35 industries, including those mak-
ing solders, batteries, alloys, glass, paints, pigments, ceramics, dental
amalgams, electric instruments, and vapor lamps. These uses are in addi-
tion to the large use of the material for electroplating, textile printing,
welding, and zinc refining.
Cadmium pollution occurs in the air, which then pollutes the water
and soil. Plants grown in areas in which the amounts of cadmium have
been increased in the atmosphere contain greater quantities of cadmium
than plants grown outside polluted areas.11
Respiration of cadmium in the air and ingestion of foodstuffs con-
taining cadmium are the primary ways humans obtain this material.
Athanassiadis12 has discussed the toxicological effects of cadmium and
should be referred to for more detail on this subject.
Selenium
Stahl in his review on selenium13 reported very little information
on human health risks. It is clear, however, that selenium is a hazard-
ous material and that human exposure must be kept to a minimum. Stahl
stated that less than one month of exposure to 800 /ig/m3 of hydrogen
selenide has been known to cause symptoms of poisoning. The American
Conference of Governmental Industrial Hygienists (ACGIH) set the TLV
for occupational exposure during 40-hour weeks with 8-hour days at 200 fxg/m3
for all selenium compounds except selenium hexafluoride, which was set
at 400 fig/m3 . 14
Mercury
A great deal has been written about the chronic and acute toxicity
of mercury and its compounds. Much of this work was summarized by Stahl.15
1-4
-------
The ACGIH16 has adopted the TLV of 100 jig/m3 of mercury vapor and inorganic
compounds of mercury for an 8-hour work day. There is considerable
evidence that this TLV of 100 ^ig/m3 may be too high, and it probably
should be lowered to 50 jLtg/m3 for an 8-hour day.16 A TLV of 10 fj,g/m3
for a 24-hour day has been suggested. A TLV of 100 jig/m3 seems
unrealistically high since air at 75°F saturated with mercury vapor
would contain only 18 /ig/m3 according to Stahl.
Summary of Health Risks
A summary of the health risks entailed in exposure to asbestos
and the metals included in this study is given below. These results were
used in determining the sensitivities needed in the analytical procedures
selected for these materials.
Pollutant
Level Considered Safe
for Human Exposure*
Asbestos
Beryllium
Lead
(1967) TLV - 200 |Llg/m3
Cadmium
(1971) TLV - 83 Hg/ta3 for particulates
166 /Ug/m3 for dust
Selenium
(1967) TLV - 200 fig/m3
Mercury
(1967) TLV - 100 jig/m3
*
Recommended TLV, American Conference of Govern-
mental Industrial Hygienists (1959, 1967, 1971).
1-5
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REFERENCES
Appendix 1
1. D. W. White and J. E. Burke, The Metal Beryllium, American Society
for Metals, Cleveland, Ohio (1955), p. 620.
2. Ibid., p. 621.
3. Ibid., p. 523.
4. M. W. Gafafer, Ed., Occupational Diseases, U.S. Government Printing
Office, p. 93 (1964).
5. American Conference of Governmental Industrial Hygienists: Threshold
Limit Values of Airborne Contaminants for 1968, American Conference
of Governmental Industrial Hygienists, Cincinnati, Ohio (1968) p. 11.
6. Committee on Threshold Limit Values, Documentation of Threshold Limit
Values, Rev. Ed., American Conference of Governmental Industrial
Hygienists, Cincinnati, Ohio (1966).
7. L. B. Tepper and E. A. Pfitzer, "Clinical and Biochemical Approaches
to the Story of Lead at Low Levels," Report No. APTD-0617, the Ket-
tering Laboratory, University of Cincinnati, Ohio (1970).
8. R. G. Smith, "Air Quality Standards for Lead," Monograph No. 69-11,
Air Quality Monographs, American Petroleum Institute, Division of
Environmental Affairs, New York, New York (1969).
9. T. J. Haley, "A Review of the Toxicology of Lead," Monograph No. 69-7,
Air Quality Monographs, American Petroleum Institute, Division of
Environmental Affairs, New York, New York (1969).
10. L. Friberg, M. Piscator, and G. Nordberg, Cadmium in the Environment
(CRC Press, Cleveland, Ohio, 1971), pp. 92-96, 107-110.
11. L. Friberg, M. Piscator, and G. Nordberg, Cadmium in the Environment
(CRC Press, Cleveland, Ohio, 1971), p. 132.
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12. Y. C. Athanassiadis, Preliminary Air Pollution Survey of Cadmium and
Its Compounds (National Pollution Controll Administration, Publ.
No. Aptd-69-32, Raleigh, North Carolina, 1969), p. 5.
13. Q. R. Stahl, National Air Pollution Control Administration Publi-
cation No. APTD-69-47,
14. Threshold Limit Values for 1967, adopted at the 29th Annual Meeting
of the American Conference of Governmental Industrial Hygienists,
Chicago, Illinois (May 1-2, 1967).
15. Q. R. Stahl, Litton Systems, Inc., Bethesda, Maryland, September
1969 (PB 188074).
16. Threshold Limit Values for 1967, adopted at the 29th Annual Meeting
of the American Conference of Governmental Industrial Hygienists,
Chicago, Illinois (May 1-2, 1967).
1-7
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Appendix 2
MANUAL METHODS FOR MEASURING ASBESTOS, BERYLLIUM, LEAD,
CADMIUM, SELENIUM, AND MERCURY IN SAMPLES COLLECTED
FROM STATIONARY SOURCE EMISSIONS
Introduction
The methods selected for analysis of asbestos, beryllium, lead,
cadmium, selenium, and mercury present in the gas streams of stationary
sources are presented in detail in this appendix. These methods were
laboratory and field tested, except for selenium, which was tested
only in the laboratory.
These methods are intended to be used for the analysis of samples
collected from gas streams in stationary sources. Because of the wide
variation in conditions that may be encountered in the field, detailed
sampling procedures are not given. It is left to the user of these meth-
ods to supply an appropriate sample. In general, except for asbestos,
the same sampling apparatus may be used for sample collection. The
actual sampling train must be adapted to the conditions encountered
at each site and for the solutions required in the impingers. Some de-
tails relating to sampling are provided along with each procedure for
analysis.
The basic sampling device is an EPA-recommended apparatus consisting
of a probe, filter, impingers, meter box, and vacuum pump. The system
is described in EPA publication APTD 0581 and is shown in Fieure 2-1.
2-1
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ACID
TRAP
FIGURE 2-1 SAMPLING TRAIN
Definitions
Range
The range of the method of analysis is the concentrations of the
material of interest in a specified volume of emissions from the source
that will result in a sample that falls within the operational limits
of the method of analysis if a specified volume of emissions is taken.
For example, the range of selenium is 0.02-2 p,g/ft3 (0.7-70 |j,g/m3) for
a 100 ft3 (3 m3) sample. If a 100 ft3 (3 m3) sample is taken in this
concentration range, the concentration of the solution prepared using
this method of analysis will fall into the range of 2-200 |j,g Se/50 ml
toluene, which is the range that this method of analysis is capable
of analyzing.
2-2
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Sensitivity
Hie sensitivity of the atomic absorption methods is the concentra-
tion of the source emissions that will result in 1% absorption when put
into solution and analyzed, and is based in turn on the sensitivity of
the atomic absorption instrument. The sensitivity of the selenium method
is the smallest concentration of selenium in the source emission that can
be detected when dissolved and analyzed with a signal twice that of the
background noise of the colorimeter. In the asbestos method the sensi-
tivity is the smallest concentration of the asbestos fibers in the source
emission that can be detected when collected and prepared for counting by
electron microscopy.
Accuracy
The accuracy of the method is the degree to which the actual concen-
tration in the collected sample can be determined. It is stated in terms
of percentage of the actual concentration and is based on laboratory
analysis of standards and not on source samples.
Precision
The precision of the method is a measure of the reproducibility of
the analytical portion of method. It is stated in terms of the average
percentage variation among the observed values.
Units
The units used throughout the procedures were made as uniform as
possible. All concentrations in the gas phase are expressed in terms of
cubic feet, with approximate equivalent values in cubic meters given in
parentheses. These values have been rounded for convenience; 35.3 cubic
feet equal 1 cubic meter. Concentrations of materials in solutions are
generally given in micrograms per milliliter.
2-3
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SRI Methods of Analysis
Asbestos Source Emission Measurements SRI MA #1
ELECTRON MICROSCOPIC METHOD FOR MEASURING ASBESTOS
IN STATIONARY SOURCE EMISSIONS
1, Principles and Applicability
1.1 Principles
Asbestos fibers emitted from stationary sources are
collected on a Nuclepore® filter. The collected material is then
transferred to an electron microscope grid. Electron micrographs are
prepared, and the asbestos fibers are identified, sized, and counted by
visual observation.
1.2 Applicability
This method is useful for measuring asbestos emitted from
stationary sources in which at least 10% of the collected material is
chrysotile asbestos. Since the method requires judgment in identifying
asbestos fibers, amphibole type asbestos may be difficult to distinguish
from glass or other types of fibers. The method is useful for asbestos
particles varying from 0.01 to 5 microns in diameter and 0.1 to 10 mi-
crons in length.
Al.l
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SRI MA #1
2. Range and Sensitivity
2.1 Range
This method is useful for the determination of asbestos
particles collected on Nuclepore filters in the concentration range
of 6300 to 6,300,000 fibers per cubic foot (2,2 x 105 to 2.2 x 108
fibers per cubic meter ;>r 200,000 to 2,000,000 fibers per square centi-
meter of filter) using 1 to 100 ft3 (0.03 to 3 m3) samples.
2.2 Sensitivity
The method is designed to detect 6300 asbestos particles per
cubic foot (2.2 x 105 fibers per cubic meter) of gas stream sampled
when taking a 100 ft3 (3 m3) sample.
A2.1
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SRI MA #1
3. Interferences
3.1 Inorganic Fibers
Inorganic fibers with dimensions similar to those of asbestos
fibers are potential interfering materials. These include glass, ceramic,
metal, and man-made fibers. Chrysotile fibers can be distinguished
from these interfering materials by careful observation of their morphology.
3.2 Organic Fibers
Organic fibers, such as wood, wool, cotton, and synthetics,
may cause some confusion in the interpretation of photographs. These
fibers could be eliminated, if present in sufficient numbers to cause a
serious interference, by low temperature oxidation of the NucleporgS) fil-
ter, followed by collection of the noncombustibles on a second Nuclepord©
filter from a water suspension.
3.3 Nonfibrous Matter
Nonfibrous matter, if present in excess of 90^ of the col-
lected material, may make accurate chrysotile fiber counting impossible.
A3.1
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SRI MA #1
4, Accuracy, Precision, and Stability
4.1 Accuracy
The accuracy of the method is dependent on the subjective
evaluation of the person who does the particle counting. The counting
error for an experienced particle counter should be < ± 10$. The major
errors in the method are related to particle counting.
4.2 Precision
A precision of ±5$ of the particles counted should be easily
obtained.
4.3 Stability
None of the steps of the procedure is subject to great vari-
ations because of instability.
A4,l
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SRI MA #1
5. Apparatus
5.1 Sampling
Any apparatus having a suitable holder for a membrane filter
and a pump regulated to draw the gas through the filter at the prescribed
rate may be used. A sampling rate of approximately 0,1 to 0.5 ft3/min
(0.003 to 0.015 m3/min) is suitable for a dust concentration of 6300
to 6,300,000 fibers/ft3 (2.2 x 10s to 2.2 x 108 fibers/m3") with a
25-mm-diameter filter, assuming a 20-mm-diameter exposed area.
Nucleopor^5filters, Designation Number 80 CRP 025 00 (0.8 p,), or
equivalent, may be used.
5.2 Sample Treatment
5.2.1 For samples free of interfering matter, a punch, such
as a cork borer that will cleanly cut a 3-mm-diameter circle from a mem-
brane filter, may be used to prepare a portion of the collected material
for electron microscopy. A means for transferring the collected material
to an electron microscope grid is also required. The apparatus shown in
Figure 4 of a paper by Frank et al.1 is suitable for this purpose. It
consists of a flat container, such as a petri dish, containing a thin
layer of solvent and a wick for transmitting the solvent to the sample.
5.2.2 For samples contaminated with organic matter, the
apparatus under 5.2.1 is required, as well as an-apparatus for low tem-
perature combustion of the organic matter without changing the morphology
of the asbestos particles.
5.3 Analysis
An electron microscope capable of giving good resolution at
1000X on a 2 in. X 2 in. (5 cm x 5 cm) negative is required. An additional
magnification in preparing a photographic print is necessary.
A5.1
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SRI MA #1
6. Reagents and Supplies
6.1 Reagents for Sampling
None.
6.2 Reagents for Sample Preparation
Chloroform (Mallinckrodt Analyzed Reagent).
Chromium chips (99,9$ pure, Ernest F, Fullam, Inc.).
Silicon monoxide (Ernest F. Fullam, Inc.).
6.3 Reagents for Electron Microscopy
None.
6.4 Supplies
Photographic negatives and printing paper.
Nuclepor^f ilters, Designation Number 80 CRP 025 00.
6.5 Standards
Standard reference samples of asbestos from the Internations
Union Against Cancer (UICC).
A6.1
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SRI MA #1
7. Procedures
7.1 Sampling
The gas stream being sampled is drawn through a Nucleopore®
filter (0.8 n) at a suitable rate for the desired period of time.
Appropriate sampling times are given below for various asbestos concen-
trations in the gas stream in stationary sources:
Asbestos Concentration Sampling Time Sampling Rate
(10,000 fibers/ft3) * (min) (ft3/min) *
0.63-6.3 200 0.5
6.3-63 20 0.5
63-630 10 0.1
* m3 = 35.3 ft3
The sampling times for a given site must be based on experience or at
least an educated guess about the expected fiber concentration. These
sampling times were chosen to give ideal fiber densities on the electron
micrographs at 1000X magnification. These micrographs, which are 2 in. X
2 in. (5 cm x 5 cm), are then photographically enlarged to give pictures
that are 2000X.
7.2 Sample Preparation
Silicon monoxide is evaporated at a 90-degree angle on top
of the asbestos particles in the Nuclepor^filter as described by Frank
c
et al.1 to a thickness of approximately 1000 A. To apply the silicon
monoxide, a tungsten basket containing approximately 15 mg of silicon
monoxide is placed 10 cm above the filter, and the current through it
is maintained at 10 amperes for 45 seconds and at 15 to 18 amperes for ap-
proximately 90 seconds. The resulting silicon monoxide film should be
deep yellow. Following deposition of the silicon monoxide, a very light
film of chromium is deposited on top of it from an angle of 15 degrees.
The purpose of the chromium layer is mainly for additional strength. The
resulting shadows give a third dimension in the electron micrographs.
A7.1
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SRI MA #1
Several 3-mm circles are cut from the filter with a punch.
The Nuclepor^filter is then dissolved with chloroform by the method of
Frank et al., as modified by Murchio.2 In this method a block of poly-
urethane foam 5-mm thick and 10-mm square is placed in a petri dish.
Chloroform is poured into the petri dish to a level just below the top
of the polyurethane block. A 200-mesh electrolytic copper on nickel
grid is placed on the polyurethane, the sample is carefully placed on
the grid with the sample side down, and the cover is placed on the petri
dish. After approximately one hour, the grid is carefully moved to a
new location on the polyurethane. Complete dissolution of the Nuclepor^1
filter may require as long as four hours. Even then, a slight residue
may remain.
A7.2
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SRI MA #1
7.3 Electron Microscopy
Micrographs of 25 to 50 typical fields are taken on 2 in. X
2 in. (5 cm x 5 cm) negatives at 1000X magnification. Positive prints
of approximately 4 in. X 4 in. (10 cm x 10 cm) are made from the
negatives, giving a total magnification of 2000X.
7.4 Particle Identification, Counting, and Sizing
A trained observer can recognize electron photomicrographs
of chrysotile asbestos fibers from their morphology.3 Asbestos fibers
are counted in five categories according to length: > lOu, 5 to 10^t,
2 to 5n, 0.5 to 2(2, and < 0.5u. This count is performed for a minimum
of 25 fields. For good statistics at least 100 particles in a given
size category should be counted.
A7.3
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SRI MA #1
8. Standards and Calibration
8.1 Standards
Standard reference samples of asbestos are available from
the International Union Against Cancer (UICC).4
8.2 Calibration
Electron photomicrographs of standard reference samples of
asbestos of the type to be monitored should be used for comparison in
interpreting photomicrographs of unknown samples. The determination of
particle length can be calculated from electron microscope settings,
photographic printing magnification, and observed lengths of fibers in
the photographic prints.
A8.1
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SRI MA #1
9. Calculations
9.1 Particle Counting
The number of particles, n , in each size category for the
total number of fields counted is recorded. The filter area, a, repre-
sented by the total number of fields counted is recorded. The particle
density on the filter is given by n /a for each particle size category.
x
9.2 Particle Concentration
The asbestos fiber concentration in gas streams in stationary
sources, C, is expressed in particles per cubic meter. It is given by
(nx/a)A
wnere n /a is the particle density on the filter, A is the total exposed
area of the filter, and V is the volume of gas (cubic meters) sampled.
A9.1
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SRI MA. #1
10. References
1. E. R. Frank, K. R. Spurny, D. C. Sheesley, and J. P. Lodge,
Jr., Microscopie 9, 735 (1970).
2. Private communication: J. Murchio, University of California
at Berkeley.
3. P. Gross, R. T. deTreville, and Mn. N. Haller, Arch. Environ.
Health, 20, 571 (1970).
4. V, Timbrell, J. C. Gilson, and I. Webster, Int. J. Cancer, £,
406 (1968).
A10.1
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SRI Method of Analysis
Beryllium Source Emission Measurements SRI MA #2
ATOMIC ABSORPTION METHOD FOR
MEASURING BERYLLIUM STATIONARY SOURCE EMISSIONS
1. Principles and Applicability
1.1 Principles
Beryllium emissions from stationary sources containing
particulates, dust, fumes, and volatile inorganic beryllium compounds are
collected through a probe onto a membrane filter and in liquid filled
impingers. Beryllium deposits in the probe, on the filter, and in the
impingers are combined and measured by atomic absorption spectrophotometry.
1.2 Applicability
This method is useful for measuring beryllium emissions from
stationary sources such as machine shops. It is applicable to beryllium
concentrations of approximately 0.003 to 0.30(ig/ft3 (0.1 to 10 p,g/m3) .
The upper limit of this method can be extended either by taking smaller
samples or by diluting the sample taken. However, the total sample volume
should not be less than 75 ft3 (2.3 m3).
B 1.1
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SRI MA #2
2. Range and Sensitivity
2.1 Range
The range of this method as described herein is 0.003 to 0.30
(j,gBe/ft3 (0.1 to 10(j,g/m3) for a 100 ft3 (3 m3) sample of air. Higher con-
centrations can be measured if a smaller air sample is taken or if the
solution is diluted before the AA spectrophotometry^measurement is made.
Lower concentrations can be measured at reduced accuracy.
2.2 Sensitivity
The sensitivity of the total method including sampling is
dependent on the sample size. The size of the sample to be taken at a
particular source cannot be predicted without detailed knowledge of the
source and should be determined at the time of sample collection. The
sensitivity of the method is 0.003 |_ig Be/ft3 (0.1 |_Lg/m3) based on the
collection of a 100 ft3 (3 m3) sample and concentration of the beryllium
in the total sample into a 10-ml final volume of solution to be analyzed
by AA spectrophotometry. This sensitivity represents 0.03 [j, gBe/ml/l$
absorption for beryllium in the solution analyzed by AA spectrophotometry1.
B 2.1
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SRI MA #2
3. Interferences
3.1 Other Elements
Elements that can cause negative interference with the analy-
ses of Be by AA using a nitrous oxide-acetylene flame are aluminum and
silicon in quantities greater than 100 p,g/ml.2 This interference can
be eliminated by the addition of 8-hydroxy-quinoline reagent in the case
of aluminum. Since the major source of beryllium is the mineral beryl,
3Be0.Al203.6Si02, it is important that this reagent be made a part of the
standard method of analysis.2
Other metallic ions can enhance the Be signal, but these gen-
erally must be available in quantities greater than 1000 (j,g/ml, and in
most cases 4000 to 10,000 ^g/ml. These interferences can be masked
+ «
by K .3
3.2 Radioactive Materials
Be is used in nuclear reactions.4 When sampling these sources,
radioactive material must be efficiently removed before the AA analysis
of Be is done. These materials do not interfere with the absorption, but
they do contaminate the instrument and its environment, creating a
hazardous situation for the analyst. They can be removed by an
acetylacetone extraction.5
B3.1
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SRI MA p.
4. Accuracy, Precision, and Stability
4.1 Accuracy
The accuracy of the analytical method after sample collection
is ±6% in the concentration range of 0.03 to 0.3 ng/ft3. This analytical
method will detect concentrations of beryllium below 0.03 ug/ft3, but
with a decreased accuracy of ±20%, These accuracies are based on a
100-ft3 (3-m3) sample. The accuracy of the total method including
sampling was not determined owing to insufficient sampling data.
4.2 Precision
The precision of the analytical method is ±4% of the
concentration of beryllium found in the sample for the 0.03 to 0.3 jxg/ft3
range. The Drecision for samples containing beryllium below 0.03 ug^ft3
is J-11%. The values are based on a 100-ft3 (3-m3) sample. Insufficient
sampling data were collected to determine the precision of the total
method.
4.3 Stability
Instability of the sample because of hydrolysis is not a
problem at any stage of the analysis if care is taken that the pH of
the beryllium solutions is 1 or less.
B4.1
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SRI MA #2
5. Apparatus
5.1 Sampling
Any sampling apparatus may be used that has a suitable probe,
a holder for a membrane filter, impingers, and a metering system regulated
to draw the gas sample through the collection train at a prescribed flow
rate (see Section 7.1). The sampling train used by EPA and described in
APTD-0581 may be used for this analysis. This piece of equipment can be
purchased from Research Appliance Company, Route 8 and Craighead Road,
Allison Park, Pennsylvania 15101. An equivalent sampling train may also
be used.
5.1.1 Probe
Probe length will depend on the configuration of the
source. Typical probes are 1, 1.5, and 3 meters long. The 3-meter
probes are easily broken and should be used only when necessary. Suitable
probes are made of stainless steel and contain a Pyrex glass liner. Glass
lined probes should be used whenever oossible for sampling metals. Such
probes can be purchased from Research Appliance Company, Route 8 and
Craighead Road, Allison Park, Pennsylvania 15101. Any equivalent Drobe
will also be suitable.
5.1.2 Filter
Millipore Type AA filters are used in this procedure.
To ensure that there is no interference with the measurement of beryllium
on the AA spectrometer, blanks should be run on filters from the same
batch.
B5.1
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SRI MA #2
5.1,3 Collection Train
The collection train described in APTD-0581, or any
equivalent train, may be used. A suitable collection train, Model 2343
Staksraplr, is available from Research Appliance Company.
5.2 Sample Treatment
Extractions and sample dilution should be carried out in
Pyrex glassware.
5.3 Analysis
5.3.1 Atomic Absorption Instrument
Either a single or a double beam atomic absorption
spectrophotometer may be used, provided the instrument has a relative
detection limit of 0.002 fig/ml as defined by Slavin.6
5.3.2 Lamp
A hollow cathode beryllium lamp (Perkin-Elmer No. 303-
6013 or any comparable lamp) capable of producing a constant intensity
o
spectral line at 2348 A may be used.
5.3.3 Burner Head
A nitrous oxide burner head is required for
beryllium analysis.
5.3.4 Nebulizer
It is recommended that a corrosion resistant adjust-
able nebulizer (Perkin-Elmer No. 303-0404) be used since the sample solu-
tions have a high acid concentration.
5.3.5 Recorder (optional)
A multirange recorder equipped with an automatic
null recorder readout accessory is preferred for these analyses.
B5.2
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SRI MA #2
6, Reagents and Supplies
6.1 Reagents for Sampling
8N Nitric acid (reagent grade, ACS).
6.2 Reagents for Sample Preparation
Sulfuric acid (reagent grade, ACS).
Hydrochloric acid (reagent grade, ACS).
60-62$ perchloric acid (reagent grade, ACS).
Nitric acid (reagent grade, ACS).
8-Hydroxyquinoline (reagent grade, ACS).
Potassium nitrate (reagent grade, ACS).
Alconox detergent.
All solutions should be made from distilled deionized or
double distilled water.
6.3 Reagents for AA Analysis
Acetylene (Welding grade).
Nitrous oxide, 98$ minimum purity.
Air (bottled, if an air compressor is not used with the AA
unit).
6.4 Supplies
Millipore Type AA Filters or equivalent. Whatman 41 Filter
to be placed against the back side of the membrane filter as a guard
against breaking the membrane filter.
6.5 Standards
High purity beryllium metal or BeS04.4H20. (New Brunswick
Laboratories, New York; U.S. Atomic Energy Commission analyzed samples).
B6.1
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SRI MA #2
7. Procedure
7.1 Sampling
Beryllium source emissions are drawn through a probe, a
filter (millipore membrane filter Type AA backed by a Whatman 41 filter),
a series of four impingers (the first two contain 100 ml of 8 N nitric
acid, the third is dry, and the fourth contains silica gel), an acid trap
containing lOOg of 4-8 mesh soda lime, a metering system, and a pump.
Sampling should be done isokinetically. A total sample volume of
approximately 100 ft3 (~ 3 m3) should be taken. For example, a sampling
time of two hours at a flow rate of ~ 0.8 cfm may be used.
7.2 Glassware Preparation
All glassware should be rinsed and soaked for at least two
hours with Alconox detergent immediately after being used because
beryllium will absorb on the walls in time and contaminate later runs.
Glassware should be rinsed with hot water and soaked in 8 N HN03 for at
least two hours to ensure that it is free of beryllium. Before use the
glassware should be rinsed with tap water and finally with distilled
water.
7.3 8-Hydroxyquinoline Preparation
Dissolve 100 g of 8-hydroxyquinoline in approximately 150 ml
of 6 N HC1 and then dilute the solution to 500 ml with water to get a
20% w/v solution,
7.4 Sample Preparation
Wash the material that ha*3 collected in the sampling probe
into a 600-ml beaker with as little concentrated nitric acid as possible.
Rinse the probe with distilled water and add this solution to the beaker.
Place the two filters and any loose particulate matter in the beaker and
begin evaporating the solution on a hotplate with an asbestos mat. As
B7.1
-------
the evaporation proceeds, add a portion of the impinger solutions, and
continue these additions until the solution is evaporated to dryness.
Cool the residue and add 35 ml concentrated nitric acid. Heat on a hot-
plate until light brown fumes are evident to destroy any organic matter.
Cool and add 5 ml concentrated sulfuric acid and 5 ml concentrated
perchloric acid to the beaker, again place the beaker on the hotplate
and very cautiously evaporate the solution to dryness. This entire sample
preparation procedure should be performed in a perchloric acid hood
using required safety measures. Dissolve the residue in a minimum of 25^
(by volume) hydrochloric acid and filter it through a glass fiber filter.
Reduce the volume of the filtrate to 3 ml and transfer it to a 10-ml
volumetric flask. Wash the beaker twice with 2 ml of H20 and add the
washings to the flask. Add 1 ml of the 8-hydroxyquinoline solution (or
equivalent for volumes greater than 10 ml), dilute the solution to the
mark, and mix thoroughly. If other metallic ions are present in quantities
that would interfere with the beryllium analysis and that can be masked
by K+, the solution should be made 10,000 ug/ml in K+ by adding KN03.
(If the concentration of this solution is greater than 5.0 ^g Be/ml,
dilute as necessary with 1 N HC1 to adjust the concentration to that of
the standards.)
7.5 Standards Preparation
7.5,1 Stock Solution I
A solution containing 1000 |igBe/ml is prepared by
dissolving 1 g of high purity beryllium metal (New Brunswick Laboratories,
New York; U.S. Atomic Energy Commission analyzed samples) in 83 ml of
hydrochloric acid and diluting to 1000 ml. Commercially available (e.g.,
Ventron Corporation) standard stock solutions for AA that have a
concentration of 1000 (ig/ml can be used.
B7.2
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SRI MA #2
7.5,2 Stock Solution II
Prepare this solution immediately before use.
Dilute 10 ml of stock solution I to 1000 ml with 1 N HC1. This solution
contains lO^gBe/ml.
7.6 AA Unit Preparation
Allow the unit to warm up for a minimum of 30 minutes with
the beryllium cathode tube in place. Check to be sure that the nitrous
oxide-acetylene burner head is installed and ignite the flame according
to the proper procedure for the use of nitrous oxide (use air-acetylene
with a very fuel-rich yellow flame and then switch from air to nitrous
oxide. Optimize the unit with a standard solution of 2.0^,g/ml.
7.7 Standards and Filter Check Procedure
Pipette 0.0, 0.5, 1.0, 2.0, and 5.0 ml of stock solution II
into 50-ml beakers. Add 2.0-ml aliquots of stock solution II to
beakers that contain filters of the type used in air sampling devices.
At least 5 out of every 100 filters should be checked. Treat all the
samples as directed in 7.4 above. For samples whose concentrations
are below 0.5 |j,gBe/ml scale expansion can be used. Standards should
be made at 0.05, 0.10, 0.20 and 0.50jigBe/ml. Measure the absorbance
of the standards by atomic absorption.
7.8 AA Analysis of Samples
Determine the beryllium content of the samples (7.4) by AA
spectrophotometry against standards set forth in 7.7.
B7.3
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SRI MA #2
8. Standards and Calibrations
8.1 Standards
Use either pure beryllium metal, analytical grade BeS04.4H20,
or a commercially prepared standard as the standard reference material.
U.S. Atomic Energy Commission analyzed samples can be obtained from New
Brunswick Laboratories, New York.
8.2. Calibrations
Prepare a calibration curve for beryllium by plotting the
concentration of the standards against their absorbance.
B8.1
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SRI MA #2
9. Calculations
Using the calibration curve (see 8.2), determine the micrograms of
Be per milliliter of solution (7.4). Calculate the concentration of Be
in the source using the following formula:
, d
jig Be/m = C x V x F
m3*
where
C = concentration of Be |ig/ml from curve
V = original volume into which the entire sample is dissolved
for analysis
= dilution factor = diluted volume/original volume (use
only if the solution was diluted)
m3 = total volume of gas sample in cubic meters.
At sample temperature and pressure with appropriate corrections for
humidity if a dry basis is desired.
B9.1
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SRI MA #2
10. References
1. D. L. Bokowski, Am. Ind. Hyg. Assoc. J., £9, 475 (1968).
2. E. Fleet, K. V. Liberty, and T. S. West, Talanta 17, 207
(1970).
3. Ibid., p. 205.
4. R. J. Powell, P. J. Phennah, and J. E. Still, Analyst
85, 347-354 (May I960).
5. Bokowski, op. cit,, p. 479,
6. W. Slavin, Atomic Absorption Spectroscopy (Interscience
Publishers, New York, 1968), p. 61.
BIO. 1
-------
SRI Methods of Analysis
Lead Source Emission Measurements SRI MA #3
ATOMIC ABSORPTION METHOD FOR MEASURING LEAD
IN STATIONARY SOURCE EMISSIONS
1. Principles and Applicability
1.1 Principles
Lead emissions from stationary sources containing particulate
matter, dust, fumes, and volatile lead compounds are collected through a
probe onto a glass fiber filter and in impingers using a metering system
capable of controlling and determining flow rates. The filter samples
i
are ashed below 100°C to remove organic matter. The combined extracted
filter sample and impinger solutions are analyzed by atomic absorption
spectroscopy.
1.2 Applicability
This method is useful for monitoring gas streams in stationary
sources, which contain lead concentrations in the ranges of 0.06 to
2 fxg/ft3 (2 to 70 p,g/m3). The upper limit of this method can be extended
by diluting the sample taken or taking a smaller sample. The method
is applicable for particulates, dust, fumes, and volatile lead compounds;
however, the successful collection of organo lead compounds is not
yet certain under these conditions.
Cl.l
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SRI MA #3
2, Range and Sensitivity
2.1 Range
The range of the method is 0.06 to 2 ^g Pb/ft3 (2 to 7 yg/m3)
for a 100 ft3 (3 m3) sample. Higher concentrations can be determined if
the sample is diluted before it is measured by AA spectroscopy, if a
smaller sample is taken, or if a less intense Pb-line is used.
2.2 Sensitivity
The sensitivity of the total method, including sampling, is
dependent on the sample size. The size of the sample to be taken at a
particular source cannot be predicted without detailed knowledge of the
source and should be determined at the time of sample collection.
The sensitivity of the method is 0.06 jig/ft3 (2 jj,g Pb/m3) based on the
collection of a 100 ft3 (3 m3) sample and concentration of the lead in
the total sample into a 10-ml final volume of solution to be analyzed
by AA spectrometry. This sensitivity represents 0.5 |j,g/ml/l$> absorption
for lead in the solution analyzed by AA spectroscopy as described herein.2
C2.1
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SRI MA #3
3. Interferences
Source emissions will vary according to source, size, and type of
control equipment at each geographical location, resulting in samples
of unique and complex compositions. These complex samples may contain
interfering materials (such as, P0®~ and COg~)f which can either suppress
or enhance the atomic absorption results. Burnham et al.3 used a series
standard addition technique to overcome this effect on airborne particulate
samples collected from ambient air. Although organic matter can inter-
fere with Pb analysis,4 it can be removed by low temperature activated
oxygen ashing.
C3.1
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SRI MA #3
4. Accuracy, Precision, and Stability
4.1 Accuracy
The accuracy of the analytical method after sample collection
is ±3% in the concentration range of 0.6 to 2 jjg/ft3 (20 to 70 ug/m3).
Below 0,6 j^g/ft3 (20 ugAn3"), accuracy is ± 4%, Insufficient data were
collected to establish the accuracy of the total method including
sampling.
4.2 Precision
The precision of the analytical method is ± 1% of the concen-
tration of lead in the 0.6 to 2 ug/ft3 (20 to 70 jLlgAii3) range and ± 3%
below 0.6 j/g/ft3 (20 ug/m3), Insufficient data were collected to
establish the precision of the total method including sampling.
4.3 Stability
Adsorption can occur on the sides of the container in lead
solutions of low concentration (1 |j,g/ml) „ The presence of 0.1 molar
HN03 in the lead solution will eliminate the adsorption problem. None
of the other steps of the procedure are subject to variations because
of instability.
C4.1
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SRI MA #3
5. Apparatus
5 .1 Sampling
Any sampling apparatus may be used that has a suitable probe,
a holder for a glass fiber filter, impingers, and a metering
system regulated to draw the gas sample through the collection train at
a prescribed flow rate (see Section 7.1). The sampling train used by
EPA and described in APTD-0581 may be used for this analysis. This
piece of equipment can be purchased from Research Appliance Company,
Route 8 and Craighead Road, Allison Park, Pennsylvania 15101. An
equivalent sampling train may also be used.
5.1.1 Probe
Probe length will deDend on the configuration of the
source. Typical probes are 1> 1#5 and 3 meters long. The 3-meter probes
are easily broken and should be used only when necessary. Suitable
probes are made of stainless steel and contain a Pyrex glass liner.
Glass lined probes should be used whenever possible for sampling metals.
Glass lined probes can be purchased from Research Appliance Company,
Route 8 and Craighead Road, Allison Park, Pennsylvania 15101. Any
equivalent probe will also be suitable.
5.1.2 Filter
A filter made of glass fibers should be used; i.e.,
a filter such as the Gelman Type A, which is compatible with nitric acid
extractions.
C5.1
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SRI MA. #3
5.1,3 Collection Train
The collection train described in APTD-0581, or any
equivalent train, may be used. A suitable collection train, Model 2343
Staksamplr, is available from Research Appliance Company.
5.2 Sample Treatment
A low temperature, activated oxygen, dry asher (Tracerlab
Model LTA-600L) is needed to decompose organic matter in the sample.
It should be capable of sustaining temperatures of 75°C.
Extractions and sample dilution should be carried out in Pyrex
glassware. Polyethylene may be used for breakers and flasks; however,
only Pyrex glassware is recommended for volumetric equipment.
5.3 Analysis
5.3.1 Atomic Absorption Instrument
Either a single or a double beam atomic absorption
spectrophotometer may be used, provided the instrument has a relative
detection limit of 0.01 |j,g/ml as defined by Slavin.5
5.3.2 Lamp
A hollow cathode lamp Perkin-Elmer No. 303-
6039 or Varian Techtron No. 56-100029-00, or any comparable lamp) capable
of producing a constant intensity spectral line at 2833 R. may be used.
5.3.3 Burner Head
A Boling three-slot burner (Perkin-Elmer No. 303-0401)
using an air-acetylene fuel system is required for lead analysis.
C5.2
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SRI MA #3
5.3.4 Nebulizer
It is recommended that a corrosion resistant adjust-
able nebulizer (Perkin-Elmer No. 303-0404) be used since the sample
solutions have a high acid concentration.
5.3.5 Recorder (Optional)
A multirange recorder equipped with an automatic
null recorder readout accessory is preferred for these analyses.
C5 .3
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SRI MA #3
6. Reagents and Supplies
6.1 Reagents for Sampling
Nitric acid (reagent grade, ACS).
6.2 Reagents for Sample Preparation
Oxygen (industrial grade)
Acetone (reagent grade, ACS)
Nirtic acid (reagent grade, ACS)
Distilled H20.
6.3 Reagents for Atomic Absorption Spectroscopy
Air (bottled, if an air compressor is not used with the AA unit)
Acetylene (welding grade).
6.4 Supplies
Gelman Type A glass fiber filter
6.5 Standards
Lead nitrate [Pb(N03)2] 99.8+$ purity.
C6.1
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SRI MA #3
7. Procedure
7.3 Sampling
Lead source emissions are drawn through a probe, a filter
(gelman Type A or Millipore membrane filter Type AA). A series of four
impingers (the first two impingers contain 100 ml of 8 N nitric acid,
the third is dry, and the fourth contains silica gel), an acid trap
containing 100 g of 4-8 mesh soda lime, a metering system, and a pump.
Sampling should be done isokinetically. A total sample volume of
approximately 100 ft3 ( ~ 3 m3) should be taken. For example, a sampling
time of two hours at a flow rate of ~ 0.8 cfm may be used.
7.2 Lead Check on Filters
A glass fiber filter is used in the sampler since it is very
compatible with nitric acid extractions. However, since it is possible
that lead impurities may be present in the filter material, glass fiber
filters from the same lot as the one used for sample collection must be
analyzed for lead. Five out of every hundred filters should be checked
according to the procedures given in 7.3.
7.3 Sample Preparation
Molecular fragments from organic compounds in the flame
atomizer tend to interfere with lead analyses.4 Organic matter present
in the sample may be removed by low temperature ashing techniques using
activated oxygen (formed by passing oxygen through a high-frequency
electromagnetic field) impinged upon the sample, which results in slow
burning at temperatures of 70 to 80°C. Care should be used if volatile
organolead molecules are present.
C7.1
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SRI MA #3
The lead is extracted from the probe by washing with a
minimal amount (not to exceed 100 ml) of the 8 N nitric acid. The
filter is added to the probe wash. The washings and filter are added
to the impinger solutions. After all particulate has dissolved (heat
and soak for 9 hours if necessary) the solution is filtered using a
medium porosity filter suitable for use with nitric acid such as a
glass fiber filter. The filtered solution is then evaporated in a hood
to 1.0 ml and finally diluted to an exact volume of 10.0 ml with
distilled deionized water. (For smaller total lead content these
volumes can be reduced.) A single AA reading is made to determine if
the lead concentration is within the required range of the standards
(see Section 7.4). The concentration is adjusted as necessary by
diluting or concentrating the sample.
7.4 Standards Preparation
Commercially available (e.g., Ventron Corporation) standard
stock solutions for AA that have a concentration of 1000 /igAnl can be
used. To make an equivalent solution, place 1.60 g of lead nitrate
(99.8% pure) in a 1000 ml volumetric flask. Add about 900 ml deionized
distilled water and 6 ml of concentrated nitric acid to dissolve the
solid, dilute to the mark, and mix thoroughly.
C7.9,
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SRI MAl #3
A more dilute standard (50 |j,g/ml) is made from the stock
solution by diluting a 5-ml aliquot to 100 ml with 0.1N HN03. From this
solution 1, 2, 3, and 4 ml aliquots are taken and placed in 50 ml beakers.
To each beaker add 5 ml of 8 N HN03. This will cancel matrix effects
that might arise between the samples and the standards because of dif-
ferences in acid concentrations. The procedure in 7.3 is then followed.
A reagent blank should also be run.
For samples whose concentrations are below 5 jj,g Pb/ml, a
scale expansion can be used. Standards should be made at 1.0, 2.0, 3.0
and 5.0 pg Pb/ml.
7.5 Atomic Absorption Spectroscopy
Standard operating procedures as supplied by the manufacturer
are used for the atomic absorption spectrophotometer. These instructions
describe the technique of turning on the unit, inserting the hollow cath-
ode tube, and igniting the flame. The unit should be allowed to warm up
and stabilize for 15 to 30 minutes before the flame is ignited and mea-
surements are begun. The absorbances of the prepared solutions are deter-
mined using the 2833 R. lead absorption line by aspirating these solutions
one at a time into the flame and taking a reading from the recording
device 30 to 60 seconds after the aspiration has begun. This allows
the recorder enough time to reach a stable reading. Allow water to
aspirate through the flame between samples.
A calibration curve is prepared by plotting the absorbance of
the standards (ordinate) as a function of the concentration (abscissa)
in p,g/ml. The calibration curve should be linear over the concentration
range used in the analysis. The calibration curve may be used for a
direct concentration determination of the unknown sample.
If there is evidence of matrix effects in the type of sample
being analyzed, it may be necessary to use a method of additions.2'3
C7.3
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SRI MA #3
8. Standards and Calibration
8.1 Standards
Lead nitrate (99.8$ pure).
8.2 Calibration
The calibration curve for lead should be obtained from 0 to
20 (xg/ml by plotting the absorbance for the standard working solutions
(ordinate) against the concentrations (abscissa) inng/ml. This range
may be expanded, but it is preferable to keep the concentration of the
unknown sample within the optimum rather than to extend the range.
C8.1
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SRI MA #3
9. Calculations
The concentration of Pb in the gas stream is given by the following
equation:
_ , , C X V X dF
Pb/m3 = —
m
where
C = concentration of Pb in |j,g/ml from the AA calibration curve
V = original volume into which entire sample is dissolved for
analysis.
*V = dilution factor = diluted vol/original vol
(used only if the solution was diluted)
m3 = total volume of gas stream sampled in cubic meters.
-ft
At sample temperature and pressure with appropriate corrections for
humidity if dry basis is desired.
C9.1
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SRI MA. #3
10. References
1. Air Quality Data, 1966, USDHEW, Raleigh, North Carolina,
NAPCA Publication No. APTD 68-9 (1968), p. 30.
2. Analytical Methods for Atomic Absorption Spectrophotometry,
Perkin-Elmer Corporation (March, 1971),
3. C. D. Burnham, E. E. Moore, T. Kowalski, and J. Krasniewski,
"Detailed Study of Lead Determination in Airborne Particulates
over Morton Grove, Illinois, by Atomic Absorption Spectro-
scopy," Appl. Spectrosc., 24 411-414 (1970).
4. H. Delia Fiorentina, "Determination of Cations in Air,"
CEBEDEAU (Cent. Beige Etude Doc. Eaux), 23, 483 (1970). (Fr).
5. W. Slavin, Atomic Absorption Spectroscopy (interscience
Publishers, New York, 1968), p. 61.
C10.1
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SRI Methods of Analysis
Cadmium Source Emission Measurements SRI MA #4
ATOMIC ABSORPTION METHOD FOR MEASURING CADMIUM
IN STATIONARY SOURCE EMISSIONS
1. Principles and Applicability
1.1 Principles
Stationary source emissions containing cadmium dust, par-
ticulates, fumes, and volatile cadmium compounds are collected by
using a vacuum sampling system containing a probe, impingers, and a
filter. The collected material is dissolved in an acid and filtered.
The cadmium concentration is measured on an atomic absorption spectrometer
using an air-acetylene flame and a cadmium hollow cathode tube.
1.2 Applicability
This method can be used to monitor stationary source gas streams
in which cadmium exists as particulate matter, mists, or fumes, in
concentrations in the range of 0.025 to 0.2 |ig/ft3 (0.8 to 7 (a,g/m3).
The upper limit- of this method can be extended by diluting the sample
taken or by taking a smaller sample.
Dl.l
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SRI MA #4
2. Range and Sensitivity
2.1 Range
The range of the method is 0.025 to 0.2 ^.g/ft3 (0.8 to
7 |j,g Cd/m3) for a 100 ft3 (3 m3) sample. Higher concentrations can be
determined if the sample is diluted before it is measured by AA
spectroscopy or if a smaller sample is taken,
2.2 Sensitivity
The sensitivity of the total method including sampling is
dependent on the sample size. The size of the sample to be taken at a
particular source cannot be predicted without detailed knowledge of the
source and should be determined at the time of sample collection. The
sensitivity of the method is 0.025 p,g Cd/ft3 (0.8 |ig Cd/m3) based on the
collection of a 100 ft3 (3 m3) sample arid concentration of the cadmium
in the total sample into a 10-ml final volume of solution to be
analyzed by AA spectroscopy. The sensitivity represents 0.25 ng/ml/l%
absorption for cadmium in the solution analyzed by AA spectroscopy as
described herein.1
D2.1
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SRI MA #4
3. Interferences
Unique and complex conditions exist at each stationary source or
type of source, making chemical interferences in any given sample
difficult to predict. However, on the basis of laboratory conditions,
Ramakrishna et al.2 found that B402 , SiO2 , C0| , HC03, and HAs04 tend
to interfere in the AA analysis for cadmium. These interferences are
effectively overcome by acidification of the sample or by adding ethyl-
enediaminetetraacidic acid (EDTA) to the solutions. Pulido et al.3 found
that phosphate in concentrations above 0.1 M could decrease the AA response
and that sodium chloride in concentrations above 0.01 M could increase
the response. It is not anticipated that stationary source emissions of
cadmium will contain large amounts of NaCl or phosphates. The method
of Lehnert et al.4 can be used to extract the Cd2+ from a pH 3 solution
(adjusted if necessary) using a chelating agent such as ammoniumpyrrolidine
dithiocarbamate (APDC) in methylisobutylketone (MIBK).
D3.1
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SRI MA #4
4. Accuracy, Precision, and Stability
4,1 Accuracy
The accuracy of the analytical method after sample collection
based on a 100 ft3 (3 m3) sample is ±3$ in the concentration range of 0.05
to 0.2 jxg/ft3 (2 to 7 ^tg/m3), providing the sampling device has been
calibrated and the AA spectrometer is operating at optimum sensitivity.
Below 0.05 jLtg/ft3 (2 /ig/m3), the accuracy is ±4$. Insufficient data were
/
gathered to determine the accuracy of the total method including sampling.
4.2 Precision
The precision for the analytical method for determining
cadmium in stationary source gas streams is ± 3% with concentrations of
cadmium of 0.025 to 0.2 ug/ft3 (0.8 to 7 ugCd/m3). Insufficient data
were gathered to determine the precision of the total method including
sampling.
4.3 Stability
Instability of the sample is not a problem at any stage
of the analysis.
D4.1
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SRI MA #4
5. Apparatus
5.1 Sampling
Any sampling apparatus may be used that has a suitable probe,
a holder for a glass fiber or membrane filter, impingers, and a metering
system regulated to draw the gas sample through the collection train at
a prescribed flow rate (see Section 7.1). The sampling train used by
EPA and described in APTD-0581 may be used for this analysis. This piece
of equipment can be purchased from Research Appliance Company, Route 8
and Craighead Road, Allison Park, Pennsylvania 15101. Any equivalent
sampling train may also be used.
5.1.1 Probe
Probe length will depend on the configuration of the
source. Typical probes are 1, 1.5 and 3 meters long. The 3-meter probes
are easily broken and should be used only when necessary. Suitable probes
are made of stainless steel with a Pyrex glass liner and can be purchased
from Research Appliance Company, Route 8 and Craighead Road, Allison Park,
Pennsylvania 15101. Any equivalent probe will also be suitable.
5.1.2 Filter
The filter should be made of glass fibers; e.g.,
a Gelman Type A filter, which is compatible with nitric acid extractions.
It is possible that cadmium impurities may be present in some glass filters
(see Section 7.2). It may be necessary to leach the filters with acid,
thoroughly rinse them with distilled water, and dry them before they can
be used in the sampling device.
D5.1
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SRI MA #4
5.1.3 Collection Train
The collection train described in APTD-0581.or any
equivalent train may be used. A suitable collection train, model 2343
Staksamplr, is available from Research Appliance Company.
5.2 Sample Treatment
Extractions and dilutions of the samples are carried out in
Pyrex or borosilicate glassware. (Although polyethylene beakers can be
used, only glassware is recommended for the volumetric equipment.)
5.3 Analysis
5.3.1 Atomic Absorption Spectrometer
Either a single or double beam atomic absorption
spectrometer may be used. Instrument selection should be limited to
reliable manufacturers with instruments operable at a minimum cadmium
sensitivity of 0.005 p,g/ml.5
5.3.2 Lamp
A cadmium hollow cathode lamp (Perkin-Elmer No.
303-6016, Varian Techtron No. 56-100008-00, or any comparable lamp)
o
operating at 2288 A is required for the procedure.
5.3.3 Burner Head
A Boling three-slot burner (Perkin-Elmer No. 303-0401
for use with an air-acetylene flame is required.
5.3.4 Recorder (Optional)
A multirange recorder equipped with an automatic null
recorder readout accessory is preferred for these analyses because it
increases ease of analyses and may reduce errors because drifts in the
AA signals are easily detected with a continuous record.
D5.2
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SRI MA #4
6. Reagents and Supplies
6.1 Reagents for Sampling
Nitric acid (reagent grade, ACS).
6.2 Reagents for Sample Preparation
Oxygen (industrial grade)
Nitric acid (reagent grade, ACS)
Acetone (reagent grade, ACS).
6.3 Reagents for Atomic Absorption Spectroscopy
Air (bottled, if an air compressor is not used with the
AA unit.
Acetylene (welding grade)
6.4 Supplies
Gelman Type A glass fiber filter
6.5 Standards
Cadmium metal 99.99+$ purity or
Ventron (Alfa Products) cadmium AA standard.
D6.1
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SRI MA #4
7. Procedures
7.1 Sampling
A vacuum system is used to draw samples through a probe, a
filter, and a series of impingers (the first two contain 100 ml of 8 N
nitric acid, the third is dry, and the fourth contains silica gel).
The impingers should be followed by an acid trap containing 100 g
of 4-8 mesh soda lime. Sampling should be done isokinetically. A
total sample volume of 100 ft3 (~ 3 m3) should be taken. For example,
a sampling time of two hours at a flow rate of 0.8 cfm may be used.
7.2 Cadmium Check on Filters
A glass fiber filter is used in the sampler since it is very
compatible with nitric acid extractions. However, since it is possible
that, cadmium impurities may be present in the filter material, 5
fiber filters from every lot of 100 used for sample collection should be
analyzed for cadmium.
Each filter is extracted with two 8 N nitric acid washes
of sufficient volume to cover them. Each filter is washed with two 10-ml
portions of distilled water. All washes are combined in a beaker, fil-
tered, and evaporated on a hot plate nearly to dryness (approximately 1 ml).
The remaining solution is then quantitatively transferred to a 10-ml
volumetric flask and diluted to the mark. The solution is analyzed for
cadmium on the AA spectrometer. A blank should be run. If the cadmium
background is found to be greater than 0.25 (j, per filter, a preliminary
leaching step must be used to eliminate it. The filters are leached
with 8 N HN03, washed with distilled water, dried and repackaged.
D7.1
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SRI MA #4
7.3 Sampling Preparation
The cadmium-containing materials collected in the probe and
on the glass filter are dissolved with a minimal amount (not to exceed
100 ml) of 8 N nitric acid. The solution can be poured repeatedly
through the probe and then used to leach the filter. This solution
is added to those from the impingers, and the combined solutions plus
the filter are allowed to stand until the combined particulates have dis-
solved (heat if necessary) or for a maximum of two hours. Heat may be applied
if necessary. This treatment should dissolve all cadmium compounds. The
resulting solution is filtered through a medium porosity filter suitable for
use with nitric acid, such as a glass fiber filter. The volume is reduced by
heating in a hood or using vacuum pumping to a volume of approximately 1 ml.
The filtrate is then quantitatively transferred to a 10-ml volumetric flask and
diluted to the mark with distilled water; for greater sensitivity, samples
may be diluted to smaller volumes. An initial absorption reading of the
solution is taken on the AA spectrophotometer and the concentration is
adjusted if necessary by diluting an aliquot until the absorption reading on
the AA spectrophotometer falls within those readings obtained from the
standards. A blank should be run with each set of samples.
7.4 Standards Preparation
One gram of accurately weighed, high purity cadmium metal is
dissolved in 100 ml of 1 N HN03. This solution is diluted to 1000 ml
with distilled water to obtain a 1000-^g/ml stock solution. Commercial
AA standards at this concentration are available and can be used.
From the above solution another stock solution is prepared
by taking a 10-ml aliquot and diluting it to 100 ml to obtain a 100-|xg/ml
solution. A working stock solution is prepared by diluting a 5-ml aliquot
to 100 ml to obtain a 5.0-jig/ml solution. The working standards are prepared by
adding 0, 1, 2, 3, and 4 ml aliquots of the working stock solution to
D7.2
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SRI MA #4
50-ml beakers. To this, 5 ml of 8 N HN03 is added. The solution is
filtered and the volume is reduced by heating to 1 ml. The resulting
solution is quantitatively transferred to a 10-ml volumetric flask and
diluted to the mark with distilled water.
7.5 Atomic Absorption Spectrometry
Standard operating procedures as supplied by the manufacturer
are used for the atomic absorption spectrometer. The unit should be
allowed to warm up and stabilize for 15 to 30 minutes before the flame
is ignited and measurements are begun. The absorption of the prepared
o
solutions is determined using the 2288 A cadmium absorption line by
aspirating these solutions one at a time into the flame and taking a
reading from the recording device 30 to 60 seconds after the aspiration
has begun (this allows the recorder enough time to reach a stable
reading). Distilled water is allowed to aspirate through the flame
between samples.
A calibration curve is prepared by plotting the absorbances
of the standards (ordinate) as a function of the concentration (abscissa)
in (xg/ml. The calibration curve should be linear over the concentration
range used in the analysis. The calibration curve may be used for a
direct concentration determination of the unknown sample.
D7.3
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SRI MA #4
8. Standards and Calibration
8.1 Standards
Pure cadmium metal.
8.2 Calibration
The calibration curve for cadmium should be obtained for
solutions containing 0.5 to 2 |j,g/ml. This range may be expanded; how-
ever, it is preferable to dilute or concentrate the samples to keep
them within the optimum range. The calibration curve is obtained by
plotting absorbance (ordinate) as a function of concentration (abscissa)
in M-g/ml.
D8.1
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SRI MA #4
9. Calculation
To determine the concentration of Cd in the source sampled, use
the formula:
„ , , , C X V X dF
„g Cd/m3 = ^
where
C = concentration of Cd in (J-g/ml from curve
V = original volume into which entire gas sample is dissolved
= dilution factor = diluted vol/ original vol
(used only if solution was diluted)
m3 = total volume of gas stream sample in cubic meters.
*
At sample temperature and pressure with appropriate corrections for
humidity if a dry basis is desired.
D9.1
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SRI MA #4
10. References
1. Analytical Methods for Atomic Absorption Spectrophotometry,
Perkin-Elmer Corporation (March 1971).
2. T. V. Ramakrishna, J. W. Robinson, and P. W. West, "Deter-
mination of Copper, Cadmium, and Zinc by Atomic Absorption
Spectroscopy," Anal. Chem. Acta, 37, 20-26 (1967).
3. P. Pulido, K. Fuwa, and B. L. Vallee, "Determination of Cad-
mium in Biological Materials by Atomic Absorption Spectro-
photometry," Anal. Biochem., \A, 393-404 (1966).
4. E. Lehnert, K. H. Schaller, and T. Haas, "Atomabsorptions-
spectrometrische Cadmiumbestimmung in Serum und Harn,"
Z. Klin. Chem., 6, 174-176 (1968).
5. W. Slavin, Atomic Absorption Spectroscopy (Interscience
Publishers, New York, 1968), p. 61.
D10.1
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SRI Methods of Analysis
Selenium Source Emissions Measurements SRI MA jf=5
SPECTROPHOTOMETRY METHOD FOR
MEASURING SELENIUM IN STATIONARY SOURCE EMISSIONS
1. Principles and Applicability
1.1 Principles
Selenium emissions from stationary sources containing particu-
lates, dusts, fumes, and volatile selenium compounds are collected through
a probe onto a glass fiber filter and in impingers using a metering system
capable of controlling and determining flow rates. The collected materials
are treated with nitric acid and perchloric acid to solubilize the selenium
and to destroy organic matter. The selenium content ia determined by
spectrophotometry. The basis for this method was described for ambient
air by Tabor et al.1 This method is based on oxidation of the sample with
nitric and perchloric acids followed by measurement of Se(lV) as the red
reaction product of Se(lV) and 2,3-diaminonaphthalene (DAN).
El. 1
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SRI MA #5
1.2 Applicability
This method is useful for monitoring gas streams in stationary
sources in which the selenium concentrations are in the range of 0.0?. to
2 ^ig/ft3 (0.7 to 70 |_ig/m3) The upper limit of the method can be extended
by either diluting the sample taken or by taking a smaller sample.
The method is applicable for particulates, dust, fumes, and volatile
selenium compounds except H2Se, which is not trapped in the water impingers.
(Further laboratory work on this method will be necessary to provide a
suitable impinger system for H2Se.)
El.2
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SRI MA #5
2. Range and Sensitivity
2.1 Range
The range of the method is 0.02 to 2 fig/ft3 (0.7 to 70 ^ig
Se/m3 for a 100 ft3 (3m3) sample.
2.2 Sensitivity
The sensitivity of the total method including sampling is
dependent on the sample size. The size of the sample to be taken at
a particular source cannot be predicted without detailed knowledge of
the source and should be determined at the time of sample collection.
The sensitivity of the method is 0.02 )j,g/ft3 (0.7 p,g/m3) based on the
collection of a 100 ft3 (3 m3) sample and concentration of the selenium
in the total sample into a 50-ml final volume of solution to be analyzed
by spectrophotometry as described herein. Greater sensitivity can be
achieved by using a fluorimetric method of measuring the selenium
content1 or by extracting the selenium containing complex into a
smaller volume of toluene in this procedure.
E2.1
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SRI MA #5
3• Interferences
The primary interference observable at a 2000-fold excess of foreign
ion to selenium is attributable either to substances such as hypochlorite,
which oxidize the reagent, or to reducing agents such as Sn(ll), which
reduce selenium to the elemental state. Ions such as zinc, aluminum, or
sodium can be present at a millionfold excess without causing any
interference. Macro amounts of such ions as Al(lll), Zn(ll), Cu(ll),
Ca(II)f Cd(ll), Mn(ll), Ni(ll), Mg(ll), Ba(ll), and Sr(ll) are separated
from selenium (IV) by ion exchange (by passing the sample in solution
through Dowex 50 WX 8 resin) . The presence of approximately 2500 (j,g
of tellurium causes little interference in the analysis of a sample
containing 10 |jlg of selenium. Such high concentrations of tellurium are
normally not to be expected. Since nitrite ion interferes, it
is important, in preparing the sample for analysis, to use the
minimum amount of nitric acid in dissolving the sample and to remove the
oxides of nitrogen by boiling. Nitrate ion does not appreciably interfere
with the method. Nevertheless, since both the sample solution to be
analyzed and the standard stock selenium solution are prepared by the
dissolution of the particulates or elemental selenium in nitric acid, it
is important to establish a blank reading by running through the entire
analytical procedure with an unused filter.
E3.1
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SRI MA #5
4. Accuracy, Precision, and Stability
4.1 Accuracy
The accuracy of the analytical method after sample collection
is ± 14$ in the concentration range of 0.02 to 2 jxg/ft3 90.7 to 70 fig/m3)
Since no sampling data were collected, the accuracy of the total method
could not be determined.
4.2 Precision
The precision of the analytical method after sample collection
is ± 9$. Since no sampling data were collected, the precision of the total
method was not determined.
4.3 Stability
4.3.1 Losses of selenium in samples containing organic
material have been demonstrated to be negligible in the nitric-perchloric
acid digestion step if care is taken to oxidize the sample slowly.2
4.3.2 Solid, pure DAN is slowly oxidized in air to form a
yellow-brown material. Although an aqueous solution is more readily
oxidized, it can be stored under refrigeration for three days without
being sufficiently altered to affect its use for the intended purpose.
Under the conditons described, no significant difference is perceptible
in the result of an analysis when either commercial or purified reagents
are used.
4.3.3 All work can be performed under normal laboratory
conditions; i.e., in daylight, without deaerating solutions or purifying
reagents.
E4.1
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SRI MA #5
5. Apparatus
5.1 Sampling
Any sampling apparatus may be used that has a suitable probe,
a holder for a glass liber or membrane filter, impingers, and a metering
system regulated to draw the gas sample through the collection train at
a prescribed flow rate (see Section 7.1). The EPA sampling train des-
cribed in APTD-0581 may be used for this analysis.3 Similar equipment
can be purchased from Research Appliance Company, Route 8 and Craighead
Road, Allison Park, Pennsylvania 15101. An equivalent sampling train may
also be used.
5.1.1 Probe
Probe length will depend on the configuration of the
source. Typical probes are 1, 1.5 and 3 meters long. The 3-meter probes
are easily broken and should be used only when necessary. Suitable
probes are made of stainless steel and contain a Pyrex glass liner.
Glass lined probes should be used whenever possible. Glass lined probes
can be purchased from Research Appliance Company, Route 8 and Craighead
Road, Allison Park, Pennsylvania 15101. Any equivalent probe will also
be suitable.
5.1.2 Filter
The filter should be made of glass fibers; e.g., a
Gelman Type A filter, which is compatible with nitric acid extractions.
Selenium impurities may be present in some glass filters (see Section 7.2)
and it may be necessary to leach the filters with acid, thoroughly rinse
them with distilled water, and dry them before they can be used in the
sampling device.
E5.1
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SRI MA #5
5.1.3 Collection Train
The collection train described in APTD-0581, or any
equivalent train, may be used.3 A suitable collection train, Model 2343
Staksamplr, is available from Research Appliance Company.
5.2 Sample Treatment
Ordinary laboratory Pyrex glassware that has been thoroughly
cleaned should be used for these analyses. Glassware required includes
500-ml and 100-ml beakers, 125-ml separatory funnels fitted with Teflon
stopcocks and stoppers, volumetric flasks, pipets, and a 25-ml buret filled
to the 10-ml mark with Dowex 50 WX 8, 50 to 100 mesh resin in the acid form.
Also needed are a pH meter with microelectrodes (glass-calomel), a stirrer,
and a hot plate.
5.3 Spectrophotometry
A Beckman Model DU, Perkin-Elmer Model 202, or Bausch and Lomb
Spectronic 20 Spectrophotometer, with 1-cm cells may be used. Any equiva-
lent spectrophotometer may be used.
E5.2
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SRI MA #5
6. Reagents and Supplies
6.1 Reagents
6.1.1 All reagents should be prepared from analytical
grade chemicals low in selenium, using distilled water.
6.1.2 2,3-Diaminonaphthalene (DAN), C10He(NH2)2, reagent-
dissolve 1.00 g of 2,3-diaminonaphthalene (Aldrich Chemical Company,
Milwaukee, Wisconsin, or equivalent) in 1 liter of 0.01 N hydrochloric
acid, using a stirrer. Pure DAN is a white crystalline solid. It is
slowly oxidized in air to form a yellow-brown material. Although an
aqueous solution is more readily oxidized, it can be stored for three
days under refrigeration without being sufficiently altered to affect its
use for the intended purpose.
6.1.3 0.1 M Ethylenediaminetetraacetic acid disodium salt
(EDTA) solution—dissolve 33.6 g of the disodium salt of EDTA
in a volume of distilled water and dilute to 1000 ml in a volumetric
flask.
6.1.4 0.1 M Sodium fluoride, NaF, solution—dissolve 0.42 g
of NaF in a volume of distilled water and dilute to 100 ml in a volumetric
flask.
6.1.5 0.1 M Sodium oxalate, Na2C204 solution—dissolve
1.34 g of Na2C204 (Sorenson, Fisher Certified Reagent) in a volume of
distilled water and dilute to 100 ml in a volumetric flask.
6.1.6 Toluene, CGH5CH3—Fisher Certified Reagent or
equivalent. Purified Fisher's toluene may also be used.
6.1.7 IN and 0.1 N Sodium hydroxide, NaOH—dissolve 40 g
of NaOH pellets in a volume of distilled water and dilute to 1000 ml in a
volumetric flask (l N NaOH). Dissolve 4.0 g of NaOH pellets in a volume
of distilled water and dilute to 1000 ml in a volumetric flask (0.1 N NaOH).
6.1.8 Concentrated nitric acid, HN03— Fisher Reagent 69-71$
by weight, 15.8 N, or equivalent analytical reagent grade.
E6.1
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SRI MA #5
6.1.9 Sixty percent perchloric acid, HC104—Fisher Reagent,
60-62$ by weight, or equivalent analytical grade.
6.1.10 Dowex 50 WX 8, 50 to 100 mesh ion exchange resin.
6.2 Supplies
Gelman Type A glass fiber filter.
E6.2
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SRI MA #5
7. Procedure
7.1 Sampling
Selenium source emissions are sampled by drawing a gas sample
through a probe, a glass fiber filter (Gelman Type A), a series of four
impingers (the first two contain distilled water, the third is dry, and
the fourth contains silica gel), and a metering system. Sampling should
be done isokinetically. A total sample volume of approximately 100 ft3
(3 m3) should be taken; e.g., a sampling time of two hours at a flow
rate of 0.8 cfm (0.02 m3/min) may be used.
7.2 Selenium Check on Filters
A glass fiber filter is used in the sampler since it is very
compatible with nitric acid extractions. However, since selenium impuri-
ties possibly may be present in the filter material, several glass fiber
filters from the same lot as the one used for sample collection must be
analyzed for selenium.
Five filters out of every lot of 100 are used for the selenium
spot-check. The filters used for this check are treated and analyzed by
the procedures given in 7.3 and 7.4. If the selenium background is found
to be greater than 0.7 jj,g per filter, a preliminary leaching step must
be used to eliminate the excess. The filters are leached with 8 N HN03,
washed with distilled water, dried and repackaged.
7.3 Sample Preparation
The selenium is extracted from the probe by washing
with a minimal amount (not to exceed 100 ml) of the 8 N nitric acid.
This extracted selenium solution is combined with the impinger solu-
tions. The filter is added and allowed to soak until the particulate is
dissolved. The solution is then filtered. The filtrate is then
evaporated in a hood to approximately 10 ml and 1 ml of 60% perchloric
acid is added cautiously (a perchloric acid hood and the necessary equipment
to support the glassware should be used) . The mixture is allowed to stand
E7.1
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SRI MA #5
at room temperature with occasional shaking until the foaming ceases. Heat
from a burner is then applied (with great caution) until the initial rapid
oxidation begins. The heat is removed and the.oxidation is allowed to con-
inue until reaction has subsided. This treatment destroys any organic matter
present and oxidizes any elemental selenium to Se(lV). After dissolution,
careful boiling will remove oxides of nitrogen and some excess nitric acid. The
solution is reduced to a volume of 1 ml; 25 ml of distilled water is then
added and the solution is then reboiled. Removal of oxides of nitrogen
through boiling is necessary to prevent nitrite ion interference. The
resulting solution can then be analyzed for selenium by following the
prescribed procedures given in Section 7.5.
7.4 Standard Preparation
7.4.1 standard stock selenium solution (selenious acid,
H2Se03)—a solution containing 0.50 mg of selenium/ml is prepared by dissolving
50 mg of pure selenium metal (Fisher Certified Reagent, specially
purified) in a few drops (minimum necessary) of concentrated nitric
acid, boiling gently to expel brown fumes, and making up to 100 ml
with distilled water,
7.4.2 Standard working selenium solutions—the standard stock
solution, as prepared under 7.4.1, is diluted as necessary for standard
working solution. Dilute 20 ml of stock selenium solution to 100 ml with
distilled water. This solution contains 100 p,g Se/ml. Dilute 10 ml of
100 p,g/ml solution to 100 ml with distilled water. This solution contains
10 fxg Se/ml.
7.5 Spectrophotometric Procedure
7.5.1 After appropriate treatment to dissolve the sample,
the solution is adjusted to pH 2 with 1 N and 0.1 N NaOH and is passed
through a 25-ml buret filled to the 10-ml mark with Dowex 50 WX 8, 50-
to 100-mesh resin in the acid form at a flow rate of 0.5 ml/minute. The
E7.2
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SRI MA #5
flow rate is controlled by adjusting the stopcock in the buret. The
effluent is collected &nd any remaining traces of selenium are washed
from the column with 20 ml of distilled water. To this solution is added
5 ml of 0.1 M EDTA, 1 ml of 0.1 M sodium fluoride, and 1 ml of 0.1 M sodium
oxalate; the solution is then readjusted to pH 1.5-2.5 with the 1 and
0.1 N NaOH. Five ml of 0.1$ DAN solution is then added, mixed thoroughly,
and allowed to stand for two hours.
7.5.2 The solution is transferred to a separatory funnel,
exactly 50 ml of toluene is added, and the piazselenol is extracted by
shaking for 30 seconds. Separate. To remove droplets of water, the
toluene layer is filtered into the cuvette through a small filter paper
plug placed in the stem of the separatory funnel.
7.5.3 The absorbance is determined at 380 nm using a
reagent blank. The calibration curves follow Beer's law over the range
0 to 200 ng of selenium per 50 ml of toluene in a 1-cm cell at this
wavelength.
E7.3
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SRI MA #5
8. Calibration
8.1 Prepare a set of standard solutions by appropriately diluting
with distilled water, accurately measured volumes of standard stock
selenium solution (section 7.4.1), and standard working selenium solutions
(section 7.4.2). Representative concentrations should range from 0-200
(j,g of selenium for the spectrophotometry procedure (use the 100 and the
10 fj,g Se/ml working selenium solutions, section 7.4.2 Include a reagent
blank.
8.2 Follow the procedures outlined under sections 7.3 and 7.5.
8.3 Construct calibration curves by plotting absorbance values
versus |ig Se/50 ml in the standard solution. The calibration curves
follow Beer's law over the range 0-200 (j,g selenium/50 ml of toluene in
a 1-cm cell at prescribed wavelength.
E8.1
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SRI MA. #5
9. Calculations
9.1 Use the calibration curve to determine the concentration of
selenium in the solutions measured by spectrophotometry.
9.2 Concentration of selenium in the sample is
d
„ , , C X V X F
Hg Se/m =
C = concentration of Se in |j,g/ml from curve
V = original volume into which entire gas sample was dissolved
F = dilution factor = diluted volume/original volume
(use only if solution was diluted)
m3 = total volume of gas sample in cubic meters.
*
At sample temperature and pressure with appropriate corrections for
humidity if a dry basis is desired (see Ref. 3).
E9.1
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SRI MA #5
10 References
1. E. C. Tabor, M. M. Braverman, H. E. Buniotead, A. Cavotti,
H. M. Donaldson, T. Dubois, and R. E. Kupel, Health Lab. Sci.
7, 96-101 (1070).
2. J. H. Watkinson, Anal. Chem., 38, 92 (1966).
3. EPA publication APTD-0581.
E10.1
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SRI Methods of Analysis
Mercury Source Emissions Measurements SRI MA. #6
FLAMELESS ATOMIC ABSORPTION METHOD
FOR MEASURING MERCURY IN STATIONARY SOURCE EMISSIONS
1. Principles and Applicability
1.1 Principles
Mercury emissions from stationary sources containing mercury
compounds and elemental mercury are sampled through a probe, followed by
a pyrolysis furnace and a solid scrubber for S02, and collected in im-
pingers containing IC1 solution. The mercury deposited in the probe is
combined with that collected in the impingers and the total mercury con-
centration is measured by flameless atomic absorption spectroscopy.1
1.2 Applicability
This method is useful for monitoring stationary sources for
total mercury content measured as elemental mercury, regardless of the
chemical form in which the mercury actually exists in the source. It is
applicable to mercury concentrations of approximately 0.005 to 0.05 p,g/ft3
(0.15 to 1.5 |j,g/m3). The upper limit of the method can be extended by
either diluting the sample taken or by taking a smaller sample. However,
the sample volume taken should not be less than 50 ft3 (1.5 m3). Typical
sources for which this method was designed are chloralkali plants and
nonferrous metal smelters in which gas streams contain primarily nitrogen
and oxygen.
Fl.l
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SRI MA #6
2. Range and Sensitivity
2.1 Range
The range of this method as described herein is 0.005 to
0.05 fig Hg/ft3 (0.15 to 1.5 p,g/m3) for a 100 ft3 (3 m3) sample for samples
containing less than 0.1$ S02. For sources containing high levels of S02
(~7$) the procedure will sample only approximately 10 ft3 (0.3 m3) before
the S02 scrubber becomes ineffective and sampling must be discontinued. In
this case the range of the method is 0,05 to 0.5 p,g Hg/ft3 (1.5 to 15
|ig/m3) . The range is dependent on the amount of gas sampled, which is in
turn dependent on the S02 present and the capacity of the Ba02 scrubber.
2.2 Sensitivity
The sensitivity of the method is 0.005 fig/ft3 (0.15 ^ig/m3)
based on a 100 ft3 (3 m3) sample and a 50 ml aliquot of the 400 ml total
volume of IC1 solution used to collect the sample. The si-ze of the sample
to be taken at a particular source cau-ot be predicteJ wituout detailed
knowledge of the source and should be determined at the tine of sample
collection.
F2.1
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SRI MA #6
3. Interferences
The primary interferences with this method are attributable to mate-
rials that reduce IC1 in the liquid scrubbing system. Any reducing agent,
such as S02, is a potential interfering material unless it is removed
upstream from the sample collecting impingers. In the present method S02
is removed by passing the sample through a scrubber packed with a
granular material coated with Ba02, which converts the S02 to a
nonvolatile barium salt. All mercury compounds are converted to elemental
mercury vapor in a pyrolysis tube (750°C) so the mercury can be quantita-
tively collected in the IC1 solution. Some of the particulate mercury may
be deposited in the probe. This material is washed out with IC1 solution,
+ 2
which converts any mercury to Hg
F3.1
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SRI MA #6
4. Accuracy, Precision, and Stability
-1.1 Accuracy
The accuracy of the analytical method after sample collection is
±3.' in the range of 0.005 to 0.05 fig/ft3 (0.15 to 1.5 fig/m3) for a 100
ft3 (3 m3) sample. Insufficient sampling data were collected to determine
the accuracy of the total method.
4.2 Precision
The precision of the analytical method after sample collection
is estimated to be ±5\- for a 100 ft3 (3 m3) sample. The precision of the
total method including sampling could not be determined owing to the lack
of sampling data.
1.3 Stability
+ 8
The collected samples containing a concentration of Hg on
the order of 1 ~g/ml should be analyzed within a few hours of sampling.
It has been our experience that mercury is lost from the sample solutions
when they are allowed to stand more than a few hours after collection.
F4.1
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SRI MA #6
5. Apparatus
5.1 Sampling
Any sampling apparatus may be used that has a suitable probe,
impingers, and a metering system regulated to draw the gas sample through
the collection train at a prescribed flow rate (see Section 7.1).2 guch
equipment can be purchased from Research Appliance Company, Route 8 and
Craighead Road, Allison Park, Pennsylvania 15101. An equivalent sampling
train may also be used. In addition to this basic equipment, provision
must be made for a pyrolysis tube to decompose mercury compounds and a
solid scrubber to remove sulfur dioxide. A cooling loop should be
provided between the pyrolysis tube and the scrubber. The pyrolysis tube
and Ba02 scrubber are placed between the probe and first impinger, the
pyrolysis tube being first.
5.1.1 Probe
Probe length will depend on the conliguration of tne
source. Typical probes are 1, 1.5 and 3 meters long. The 3-meter probes
are easily broken and should be used only when necessary. Suitable probes
are made of stainless steel and contain a Pyrex glass liner. Glass lined
probes should be used whenever possible. Glass lined probes can be pur-
chased from Research Appliance Company, Route 8 and Craighead Road,
Allison Park, Pennsylvania 15101. Any equivalent probe will also be
sui table.
F5.1
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SRI MA #6
5.1.2 Filter
The use of the pyrolysis tube to convert all the
mercury present in the emission gases collected to a vapor state makes
the use of a filter unnecessary unless large quantities of particulates
are present. The filter should be made of glass fibers; e.g., a Gel-
man Type A filter, which is compatible with acid extractions. It is pos-
sible that mercury impurities may be present in some glass filters (see
Section 7.2) . It may be necessary to leach the filters with IC1, thoroughly
rinse them first with 6 N HC1 and then with distilled water, and dry them
before they can be used in the sampling device.
5.1.3 Collection Train
The EPA collection train,2 or any equivalent
train, may be used. A suitable collection train, Model 2343 Staksamplr,
is available from Research Appliance Company.
5.2 Sample Treatment
Ordinary laboratory Pyrex glassware that has been thoroughly
cleaned may be used for these analyses. The glassware should be rinsed
with 1.1 v/v nitric acid, tap water, 0.1 M IC1, and distilled water, in
that order.
5.3 Spectrophotometry
5.3.1 Atomic Absorption Instrument
Either a single or a double beam atomic absorption
spectrophotometer may be used, provided the instrument has a relative ¦
detection limit of 0.5 /ig/ml. The AA unit should be fitted with a
glass cell (approximately 1.5 in o.d. x 7 in.) with quartz glass
windows.
F5.2
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SRI MA #6
5.3.2 Lamp
A hollow cathode mercury lamp capable of producing
o
a constant intensity spectral line at 2537 a is used.
5.3.3 Gas Sampling Bubbler
Tudor Scientific Glass Company Smog Bubbler, Cata-
logue No. TP-1150, or equivalent.
5.3.4 Recorder
To match output of spectrophotometer.
F5.3
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SRI MA #6
6. Reagents and Supplies
6.1 Stock Reagents
6.1.1 Potassium iodide—reagent grade (ACS).
6.1.2 Distilled water.
6.1.3 Potassium Iodide Solution, 25$—Dissolve 250 g. of
potassium iodide (reagent 6.1.1) in distilled water and dilute to 1 liter.
6.1.4 Hydrochloric acid—concentrated.
6.1.5 Potassium iodate—reagent grade (ACS).
6.1.6 Iodine monochloride (iCl) 1.0 M—To 889 ml of 25$
potassium iodide solution (reagent 6.1.3), add 889 ml of concentrated
hydrochloric acid. Cool to room temperature. While stirring vigorously,
slowly add 150 g of potassium iodate and continue stirring until all free
iodine has dissolved to give a clear orange-red solution.. Cool to room
temperature and dilute to 2000 ml with distilled water. The solution
should be kept in amber bottles to prevent degradation.
6.1.7 Sodium hydroxide pellets—reagent grade (ACS).
6.1.8 Nitric acid—reagent grade (ACS).
6.1.9 Hydroxylamine sulfate—reagent grade (ACS).
6.1.10 Sodium chloride—reagent grade (ACS).
6.1.11 Mercuric chloride—reagent grade (ACS).
6.2 Sampling Reagents
6.2.1 Absorbing solution, 0.1 M ICl— dilute 100 ml of the
1.0 M ICl stock (reagent 6.1.6) to 1 liter with distilled water.
The solution should be kept in glass bottles to prevent degradation. This
reagent should be stable for at least two months; to ensure quality, how-
ever, periodic checks by thiosulfate titration should be performed.
F6.1
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SRI MA. #6
6.2.2 Wash acid—1:1 v/v nitric acid: water
6.2.3 Distilled, deionized water.
6.2.4 Silica gel—indicating type, 6- to 16-mesh, dried
at 350°F for two hours.
6.2.5 Filter (optional)—glass fiber, Gelman Type A,
Mine Safety Appliances 1106BH, or equivalent. A filter may be necessary
in cases where the gas stream to be sampled contains large quantities of
particulate matter.
6.2.6 Ba02 supported on aluminum silicate—BaOa (Bakers
Analyzed Reagent), 100 parts by weight is mixed with 70 parts by weight
of 40- to 60-mesh aluminum silicate. The mixture is heated at 420°C for
one hour and sieved, while hot, through a 25-mesh sieve. One hundred parts
by weight of additional Ba02 is added to the sieved product and it is
mixed again. The resulting mixture is heated for one hour at 420°C,
then broken up and sieved hot. The fraction that is 25- to 65-mesh is
used to pack the S02 scrubber.
6.3 Analysis
6.3.1 Sodium hydroxide, 10 N—dissolve 40.0 g of sodium
hydroxide pellets in distilled water and dilute to 100 ml.
6.3.2 Reducing agent, 12$ hydroxylamine sulfate, 12
sodium chloride—to 60 ml of distilled water, add 12 g of hydroxylamine
sulfate and 12 g of sodium chloride. Dilute to 100 ml. This quantity
is sufficient for 20 analyses and must be prepared daily.
6.3.3 Aeration gas—zero grade air.
6.3.4 Hydrochloric acid, 0.3 N—dilute 25.5 ml of con-
centrated hydrochloric acid to 1 liter with distilled water.
F6.2
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SRI MA #6
7. Procedure
7.1 Sampling
Prior to assembly, all glassware (probe, impingers, and con-
nectors) is cleaned by rinsing with wash acid, tap water, 0.1 M IC1, tap
water, and finally distilled water. Use 80 ml. of the 0.1 M IC1 as a
blank in the sample analysis.
Mercury source emissions are drawn through a probe, a
pyrolysis tube at 750°C, a Ba02 scrubber at 400 to 420°C, and a series
)
of impingers (the first two contain 150 ml of 0.1 M ICI, the third is
empty, and the fourth contains 200 g of silica gel). The impingers should
be followed by an acid trap, such as a Mine Safety Appliance Air Line
Filter, catalog number 81857 with an acid absorbing cartridge. A total
of 100 ft3 (3 m3) of gas from the source should be sampled; e.g., a
sampling time of two hours at a flow rate of ~0.8 ft3/min (0,02 m3/min)
may be used.
7.2 Mercury Check on Filters (Only if a Filter is Used)
A glass fiber filter is used in the sampler because it is
very compatible with acid extractions. However, since mercury impurities
may be present in the filter material, 5 glass fiber filters from
each lot of 100 must be analyzed for mercury.
Each filter is extracted with two 0.1 M IC1 washes of
sufficient volume to cover them. The solution is then transferred to a
clean 100 ml analysis tube and analyzed for mercury according to the
procedure given in 7.5.3 and 7.5.4. If the mercury background is found
to be greater than approximately 50 ng per filter, a preliminary
leaching as described in 5.1.2 must be used.
F7.1
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SRI MA #6
7.3 Sample Preparation
All glass storage bottles and the graduated cylinder used in
sample preparation must be precleaned as indicated in Section 7.1. This
operation should be performed in an area free of mercury contamination.
Industrial laboratories and ambient air around mercury-using facilities
are not normally free of mercury contamination. When the sampling train
is moved, care must be exercised to prevent breakage and contamination.
Disconnect the probe from the impinger train. Place the con-
tents (measured to ±1 ml) of the first three impingers into a 500-ml sam-
ple bottle. Rinse the probe and all glassware between it and the pyroly-
sis tube and the exit end of the S02 scrubber back half of the third im-
pinger with two 50-ml portions of 0.1 M IC1 solution. Add these rinses
to the first sample bottle. For a blank, place 80 ml of the 0.1 M IC1
in a 100 ml sample bottle. If usecl place the filter and 100 ml of 0,1 M
IC1 in another 100 ml sample bottle. Retain a blank. If an additional
test is desired, the glassware can be carefully double rinsed with distilled
water and reassembled. However, if the glassware is to be out of use more
than two days, the initial acid wash procedure must be followed.
7.4 Standard Preparation
7.4.1 Stock solution—add 0.1354 g of mercuric chloride
to 80 ml of 0.3 N hydrochloric acid. After the mercuric chloride has
dissolved, adjust the volume to 100 ml using 0.3 N HC1. One ml of this
solution is equivalent to 1 mg of free mercury.
7.4.2 Standard solutions—prepare calibration solutions
by serially diluting the stock solution (7.4.1) with 0.3 N hydrochloric
acid. Prepare solutions at concentrations in the linear working range
for the instrument to be used. Solutions of 1 (j,g/ml, 0.1 ^g/ml, and
0.01p,g/ml have been found acceptable for most instruments. Store all
solutions in glass-stoppered, glass bottles. These solutions should be
F7.2
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SRI MA #6
stable for at least two months; however, to ensure quality, periodic
analyses should be run and checked against previous runs.
7.5 Analysis
7.5.1 Apparatus preparation—clean all glassware according
to the procedure of Section 7.1. Adjust the instrument setting according
o
to the instrument manual, using an absorption wavelength of 2537 A.
7.5.2 Analysis preparation—adjust the air delivery pres-
sure and the needle valve to obtain a constant air flow of about 1,3 l/min.
The analysis tube should be bypassed except during aeration. Purge the
equipment for two minutes. Prepare a sample of mercury standard solution
(7.4.2) according to Section 7.5.3. Place the analysis tube in the line
and aerate until a maximum peak height is reached on the recorder. Remove
the analysis tube, flush the lines, and rinse the analysis tube with dis-
tilled water. Repeat with another sample of the same standard solution.
This purge and analysis cycle is to be repeated until peak heights are
reproducible.
7.5.3 Sample preparation—just prior to analysis, trans-
fer a sample aliquot of up to 50 ml to the cleaned 100 ml analysis tube.
Adjust the volume to 50 ml with 0.1 M IC1, it required. Add 5 ml of 10 N
sodium hydroxide, cap tube with a clean glass stopper, and shake vigorously.
Prolonged, vigorous shaking at this point is necessary to obtain an accu-
rate analysis. Add 5 ml of the reducing agent (reagent 6.3.2), cap tube
with a clean glass stopper and shake vigorously and immediately place in
sample line.
7.5.4 Mercury determination—After the system has been
stabilized prepare samples from the sample bottle according to Sec-
tion 7.5.3. Aerate the sample until a maximum peak height is reached
on the recorder. The mercury content is determined by comparing the
peak heights of the sample to the peak heights of the calibration
F7.3
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SRI MA #6
solutions. If collected samples are out of the linear range, the samples
should be diluted. Prepare a blank from the 100-ml bottle according to
Section 7.5.3 and analyze to determine the reagent blank mercury level.
F7.4
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SRI MA #6
8. Calibration
Prepare a calibration curve over a range of 50 to 500 ng Hg using
the standards in Section 7.4.?. Plot the peak heights versus the
concentrations of mercury in the standard solutions. Standards should
be interspersed with the samples since the calibration can change
slightly with time. A new calibration curve should be prepared for
each new set of samples run.
F8.1
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SRI MA #6
9. Calculations
The concentration of Hg in the gas stream is displayed in the follow-
ing equation:
„ , , C X V X dF
^g Hg/m3 = ^3*
C = concentration of Hg in (ig/ml from AA calibration curve.
V = original volume into which entire gas sample is dissolved.
= dilution factor = diluted volume/original volume (use only if origi-
nal solution was diluted)
m3 = total volume of gas stream sample in cubic meters.
*
At sample temperature and pressure with appropriate corrections for
humidity if a dry basis is desired.
F9.1
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SRI MA #6
10. References
1. W. R. Hatch and W. L. Ott, "Determination of Sub-Microgram
Quantities of Mercury by Atomic Absorption Spectrophotometry,"
Anal. Chem., 40:2085-87, 1968.
2. Robert M. Martin, (Construction Details of Isokinetic Source
Sampling Equipment, "Environmental Protection Agency, APTD-0581.
3. W. giavin, Atomic Absorption Spectroscopy (Interscience
Publishers, New York, 1968), p 61.
F10.1
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-650/4-74-015
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Survey of Manual Methods of Measurements of Asbestos,
Beryllium, Lead, Cadmium, Selenium, and Mercury in
Stationary Sources Emissions
5, REPORT DATE
September 1973
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
D.M. Coulson, D.L.Hayes, M.R. Balazs, and
*.P. Dolder
8. PERFORMING ORGANIZATION REPORT NO.
SRI Project PYU-1374
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Stanford Research Institute
fenlo Park, California 94025
10. PROGRAM ELEMENT NO.
1HA327
11. CONTRACT/GRANT NO.
68-02-0310
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
National Environmental Research Center
Quality Assurance & Environmental Monitoring Laboratory
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final A-9Q-71 - Q-30-73
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT])uring phase I of this study sources of information -were searched for methods
jf analysis for asbestos, beryllium, lead, cadmium, selenium, and mercury that would be
suitable for analyzing stationary source emissions. The primary sources of information
*ere the technical literature, telephone and direct interviews with staff members of
:ompanies that are probable stationary sources of emissions of the pollutants, and con-
:act with the Project Officer assigned by EPA. During the literature search additional
background information was obtained on the toxicity of the pollutants in this study.
Methods of analysis were then chosen on the basis of a survey of current knowledge
>n methodology, ea9e of using the procedure, availability of the equipment needed to
>erform the tests, sensivitity based upon proposed EPA standards of emission and thres-
lold limit values (TLV) adopted by the American Conference of Government Industrial
tygienists (ACGIH), and specificity requirements. One method was chosen for each pol-
.utant. A detailed discussion of how the methods of analysis were selected is presentee
During Phase II the methods of analysis selected in Phase I were tested, evaluated
md then modified if necessary. All methods were initially tested in the laboratory.
?he asbestos method was tested on samples collected at an asbestos mill. Field sampling
/as conducted for beryllium at a beryllium machining facility, but only small amounts oi
>eryllium were collected. The methods for lead and cadmium were tested successfully on
»amples collected at a municipal incinerator. No field test were conducted for seleniui
>ecause work had been stopped on this pollutant before field testing began. Field test-
;as performed on mercury in the development of the method of analysis in Phase I. Fur-
:her development and/or evaluation of these methods of analysis probably should be made
17- KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IDENTI FlERS/OPEN ENDED TERMS
c. COSATI Field/Group
,
13. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
165
20. SECURITY CLASS (This page)
Unrl aBBifitod
22. PRICE
EPA Form 2220-1 (9-73)
F10.2
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