1120 STACK SAMPLING
polyvinyl chloride (PCV) from VCM. Such sampling is often
required as part of a comprehensive program for measuring the
total VCM emitted from a PCV facility, to ensure that VCM
removed from exhaust gas streams is not simply transferred to
a water stream and discharged into the environment.
The method involves the collection of a sample of the
wastewater stream or a stream of slurry containing PCV
resin in a 60 ml vial, quickly capping the vial without trap-
ping any air, and refrigerating. The vial is then conditioned
at 90ºC for an hour. During that time the VCM dissolved in
the water or remaining in the resin (termed Residual VCM,
or RVCM) will reach equilibrium with the material that
vaporizes, forming the so-called headspace in the vial.
The headspace is subsequently sampled by syringe
and injected into a Gas Chromatograph-Flame Ionization
Detector (GC-FID). The GC-FID is calibrated using vials
filled with standard gas mixtures bracketing the expected
range. The VCM concentration in the samples is calculated
from the GC-FID response factor.
As with the other VCM Test Methods, this procedure
should be performed only by trained individuals taking spe-
cial precautions to avoid exposure to the carcinogenic VCM
vapors.Test Method 107ATest Method 107A is not a stack testing method. It is a
method used for determining the Vinyl Chloride Monomer
(VCM) content in solvent solutions or in polyvinyl Chloride
(PCV) resin slurry samples. This procedure supplements
stack testing at PCV manufacturing facilities for determin-
ing the overall emissions of VCM from exhaust gas streams
as well waste water and fugitive sources.
The method involves the collection of liquid or slurry
samples in tightly capped 20ml glass vials. A small amount
of the sample material is subsequently withdrawn by syringe
and injected into a Gas Chromatograph (GC), where the
sample vaporizes and is analyzed for VCM content. The GC
is calibrated using standard solutions of VCM in an appropri-
ate solvent. VCM content in the sample is calculated based
on the response factor of the GC.
As with other VCM Test Methods, this method should
be attempted only by trained personnel who should take spe-
cial precautions to avoid exposure to the carcinogenic VCM
vapors.Test Method 108Test Method 108 is used to determine stack gas emissions
of particulate and gaseous forms of inorganic arsenic (As)
from stationary sources. The principle is that a side stream
is withdrawn isokinetically and both the particulate and
gaseous forms are collected on a filter and in water solu-
tion. The arsenic is then concentrated, combined into one
sample, and analyzed by flame atomic absorption (AA)
spectrophotometry.
Sample train construction and operation are almost exactly
ad described in Method 5 to ensure isokinetic sampling. Twoof the impingers need to be modified slightly, the filter box is
heated, and the sample flow rate is reduced.
The filter sample is recovered by digestion. Each portion
of the sample (the impinger and filter catches) is then pre-
pared for analysis by combining with nitric acid and boiling
to dryness.
If sample concentrations are sufficiently low, special pro-
cedures must be followed to the detection limit of the AA.
Either a Vapor Generator Procedure or a Graphite Furnace
Procedure may be employed, following steps detailed in the
Method and in the manufacturer’s instructions.
Calibration standard solutions are prepared from stock
arsenic solutions. The stock solutions are prepared by dis-
solving As 2 O 3 in NaOH, adding nitric acid, heating to dry-
ness and reconstituting with water. The calibration standards
are then prepared by diluting aliquots of the stock solution
with nitric acid. The sampling train is calibrated in much the
same way as for Method 5.
Standard absorbances are then determined against blank
levels. Samples are then run in the same way, with concen-
trations determined form the resulting calibration curve.
Concurrent with analysis of samples, special Quality
Assurance Audit Samples must be analyzed. These sam-
ples are prepared and supplied through EPA’s Emissions,
Monitoring and Analysis Division in North Carolina. To be
effective in evaluating the analyst’s technique and the stan-
dards preparation, the Audit Samples must be analyzed by
the same people and using the same equipment that will be
used throughout the test program. EPA or the State agency
must be notified at least 30 days in advance to ensure timely
delivery of the Audit Samples.
The As concentration in the original stack gas is then
computed with reference to the gas flow rate, moisture con-
tent, and measured As content.
As with all of these Test Methods, Method 108 should
only be attempted by properly trained personnel using appro-
priate equipment.Test Method 108ATest Method 108A is not a stack sampling method. Instead,
it is a procedure for measuring the Arsenic (As) content of
As ore samples, particularly form nonferrous foundries. It is
used primarily for determining the As feed rate, often needed
to calculate As emission rate relative to feed rate.
In this method, the ore sample is finely pulverized,
digested in hot acid, and filtered. Depending on the con-
centration of the sample, it is then analyzed either by flame
atomic absorption spectrophotometry or by the graphite
furnace procedure. In either case, the manufacturer’s instruc-
tions are followed.
There are also two mandatory Quality Assurance checks
associated with this procedure. First, there is a check for
matrix effects, identical to the one described in Test Method- Second, it is required that all laboratories analyzing
samples according to this method first acquire audit samples
prepared and distributed by the Emissions, Monitoring and
Analysis Division of US EPA, as with Method 12. These are
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