EPA Methods List with Links

Method 12 - Determination Of Inorganic Lead Emissions From Stationary Sources

NOTE: This method does not include all of the specifications (e.g., equipment and supplies) and procedures (e.g., sampling and analytical) essential to its performance. Some material is incorporated by reference from other methods in this part. Therefore, to obtain reliable results, persons using this method should have a thorough knowledge of at least the following additional test methods: Method 1, Method 2, Method 3, and Method 5.

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1.0 Scope and Application.

1.1 Analytes.

1.2 Applicability.

This method is applicable for the determination of inorganic lead emissions from stationary sources, only as specified in an applicable subpart of the regulations.

1.3 Data Quality Objectives.

Adherence to the requirements of this method will enhance the quality of the data obtained from air pollutant sampling methods.

2.0 Summary of Method.

2.1 Particulate and gaseous Pb emissions are withdrawn isokinetically from the source and are collected on a filter and in dilute nitric acid. The collected samples are digested in acid solution and are analyzed by atomic absorption spectrophotometry using an air/acetylene flame.

3.0 Definitions. [Reserved]

4.0 Interferences.

4.1 Copper.

High concentrations of copper may interfere with the analysis of Pb at 217.0 nm. This interference can be avoided by analyzing the samples at 283.3 nm.

4.2 Matrix Effects.

Analysis for Pb by flame atomic absorption spectrophotometry is sensitive to the chemical composition and to the physical properties (e.g., viscosity, pH) of the sample. The analytical procedure requires the use of the Method of Standard Additions to check for these matrix effects, and requires sample analysis using the Method of Standard Additions if significant matrix effects are found to be present.

5.0 Safety.

5.1 Disclaimer.

This method may involve hazardous materials, operations, and equipment. This test method may not address all of the safety problems associated with its use. It is the responsibility of the user of this test method to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to performing this test method.

5.2 Corrosive Reagents.

The following reagents are hazardous. Personal protective equipment and safe procedures are useful in preventing chemical splashes. If contact occurs, immediately flush with copious amounts of water at least 15 minutes. Remove clothing under shower and decontaminate. Treat residual chemical burn as thermal burn.

5.2.1 Hydrogen Peroxide (H2O2).

Irritating to eyes, skin, nose, and lungs.

5.2.2 Nitric Acid (HNO3).

Highly corrosive to eyes, skin, nose, and lungs. Vapors cause bronchitis, pneumonia, or edema of lungs. Reaction to inhalation may be delayed as long as 30 hours and still be fatal. Provide ventilation to limit exposure. Strong oxidizer. Hazardous reaction may occur with organic materials such as solvents.

6.0 Equipment and Supplies.

6.1 Sample Collection.

A schematic of the sampling train used in performing this method is shown in Figure 12-1 in Section 18.0; it is similar to the Method 5 train. The following items are needed for sample collection:

6.1.1 Probe probe nozzle, Probe Liner, pitot Tube, Differential Pressure Gauge, filter Holder, filter Heating System, tenperature sensor, metering System, barometer, and Gas Density Determination equipment.

Same as Method 5, Sections through,, 6.1.2, and 6.1.3, respectively.

6.1.2 impingers.

Four impingers connected in series with leak-free ground glass fittings or any similar leak-free noncontaminating fittings are needed. For the first, third, and fourth impingers, use the Greenburg-Smith design, modified by replacing the tip with a 1.3 cm (1/2 in.) ID glass tube extending to about 1.3 cm (1/2 in.) from the bottom of the flask. For the second impinger, use the Greenburg-Smith design with the standard tip.

6.1.3 tenperature sensor.

Place a tenperature sensor, capable of measuring temperature to within 1C (2F) at the outlet of the fourth impinger for monitoring purposes.

6.2 Sample Recovery.

The following items are needed for sample recovery:

6.2.1 Probe-Liner and Probe-probe nozzle Brushes, Petri Dishes, Graduated Cylinder and/or Balance, Plastic Storage Containers, and Funnel and Rubber Policeman.

Same as Method 5, Sections 6.2.1 and 6.2.4 through 6.2.7, respectively.

6.2.2 Wash Bottles.

glass (2).

6.2.3 Sample Storage Containers.

Chemically resistant, borosilicate glass bottles, for 0.1 N nitric acid (HNO3) impinger and Probe solutions and washes, 1000-ml. Use screw-cap liners that are either rubber-backed Teflon or leak-free and resistant to chemical attack by 0.1 N HNO3. (Narrow mouth glass bottles have been found to be less prone to leakage.)

6.2.4 Funnel.

glass, to aid in sample recovery.

6.3 Sample Analysis.

The following items are needed for sample analysis:

6.3.1 Atomic Absorption Spectrophotometer.

With lead hollow cathode lamp and burner for air/acetylene flame.

6.3.2 Hot Plate.

6.3.3 Erlenmeyer Flasks.

125-ml, 24/40 standard taper.

6.3.4 Membrane filters.

Millipore SCWPO 4700, or equivalent.

6.3.5 Filtration Apparatus.

Millipore vacuum filtration unit, or equivalent, for use with the above membrane filter.

6.3.6 Volumetric Flasks.

100-ml, 250-ml, and 1000-ml.

7.0 Reagents and Standards.

NOTE: Unless otherwise indicated, it is intended that all reagents conform to the specifications established by the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available; otherwise, use the best available grade.

7.1 Sample Collection.

The following reagents are needed for sample collection:

7.1.1 filter.

Gelman Spectro Grade, Reeve Angel 934 AH, MSA 1106 BH, all with lot assay for Pb, or other high purity glass fiber filters, without organic binder, exhibiting at least 99.95 percent efficiency (<0.05 percent penetration) on 0.3 micron dioctyl phthalate smoke particles. Conduct the filter efficiency test using ASTM D 2986-71, 78, or 95a (incorporated by reference - see 60.17) or use test data from the supplier's quality control program.

7.1.2 Silica Gel, Crushed Ice, and Stopcock Grease.

Same as Method 5, Sections 7.1.2, 7.1.4, and 7.1.5, respectively.

7.1.3 Water.

Deionized distilled, to conform to ASTM D 1193-77 or 91, Type 3 (incorporated by reference--see 60.17). If high concentrations of organic matter are not expected to be present, the potassium permanganate test for oxidizable organic matter may be omitted.

7.1.4 Nitric Acid, 0.1 N.

Dilute 6.5 ml of concentrated HNO3 to 1 liter with water. (It may be desirable to run blanks before field use to eliminate a high blank on test samples.)

7.2 Sample Recovery.

0.1 N HNO3 (Same as in Section 7.1.4 above).

7.3 Sample Analysis.

The following reagents and standards are needed for sample analysis:

7.3.1 Water.

Same as in Section 7.1.3.

7.3.2 Nitric Acid, Concentrated.

7.3.3 Nitric Acid, 50 Percent (v/v).

Dilute 500 ml of concentrated HNO3 to 1 liter with water.

7.3.4 Stock Lead Standard Solution, 1000 g Pb/ml.

Dissolve 0.1598 g of lead nitrate [Pb(NO3)2] in about 60 ml water, add 2 ml concentrated HNO3, and dilute to 100 ml with water.

7.3.5 Working Lead Standards.

Pipet 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 ml of the stock lead standard solution (Section 7.3.4) into 250-ml volumetric flasks. Add 5 ml of concentrated HNO3 to each flask, and dilute to volume with water. These working standards contain 0.0, 4.0, 8.0, 12.0, 16.0, and 20.0 g Pb/ml, respectively. Prepare, as needed, additional standards at other concentrations in a similar manner.

7.3.6 Air.

Suitable quality for atomic absorption spectrophotometry.

7.3.7 Acetylene.

Suitable quality for atomic absorption spectrophotometry.

7.3.8 Hydrogen Peroxide, 3 Percent (v/v).

Dilute 10 ml of 30 percent H2O2 to 100 ml with water.

8.0 Sample Collection, Preservation, Storage, and Transport.

8.1 Pretest Preparation.

Follow the same general procedure given in Method 5, Section 8.1, except that the filter need not be weighed.

8.2 Preliminary Determinations.

Follow the same general procedure given in Method 5, Section 8.2.

8.3 Preparation of Sampling Train.

Follow the same general procedure given in Method 5, Section 8.3, except place 100 ml of 0.1 N HNO3 (instead of water) in each of the first two impingers. As in Method 5, leave the third impinger empty and transfer approximately 200 to 300 g of pre-weighed silica gel from its container to the fourth impinger. Set up the train as shown in Figure 12-1.

8.4 Leak-Check Procedures.

Same as Method 5, Section 8.4.

8.5 Sampling Train Operation.

Same as Method 5, Section 8.5.

8.6 Calculation of Percent Isokinetic.

Same as Method 5, Section 8.6.

8.7 Sample Recovery.

Same as Method 5, Sections 8.7.1 through, with the addition of the following:

8.7.1 Container No. 2 (Probe).

Taking care that dust on the outside of the Probe or other exterior surfaces does not get into the sample, quantitatively recover sample matter and any condensate from the Probe probe nozzle, Probe fitting, Probe liner, and front half of the filter holder by washing these components with 0.1 N HNO3 and placing the wash into a glass sample storage container. Measure and record (to the nearest 2 ml) the total amount of 0.1 N HNO3 used for these rinses. Perform the 0.1 N HNO3 rinses as follows:

Carefully remove the Probe probe nozzle, and rinse the inside surfaces with 0.1 N HNO3 from a wash bottle while brushing with a stainless steel, Nylon-bristle brush. Brush until the 0.1 N HNO3 rinse shows no visible particles, then make a final rinse of the inside surface with 0.1 N HNO3.

Brush and rinse with 0.1 N HNO3 the inside parts of the Swagelok fitting in a similar way until no visible particles remain.

Rinse the Probe liner with 0.1 N HNO3. While rotating the Probe so that all inside surfaces will be rinsed with 0.1 N HNO3, tilt the Probe, and squirt 0.1 N HNO3 into its upper end. Let the 0.1 N HNO3 drain from the lower end into the sample container. A glass funnel may be used to aid in transferring liquid washes to the container. Follow the rinse with a Probe brush. Hold the Probe in an inclined position, squirt 0.1 N HNO3 into the upper end of the Probe as the Probe brush is being pushed with a twisting action through the Probe; hold the sample container underneath the lower end of the Probe, and catch any 0.1 N HNO3and sample matter that is brushed from the Probe. Run the brush through the Probe three times or more until no visible sample matter is carried out with the 0.1 N HNO3 and none remains on the Probe liner on visual inspection. With stainless steel or other metal Probes, run the brush through in the above-prescribed manner at least six times, since metal Probes have small crevices in which sample matter can be entrapped. Rinse the brush with 0.1 N HNO3, and quantitatively collect these washings in the sample container. After the brushing, make a final rinse of the Probe as described above.

It is recommended that two people clean the Probe to minimize loss of sample. Between sampling runs, keep brushes clean and protected from contamination.

After ensuring that all joints are wiped clean of silicone grease, brush and rinse with 0.1 N HNO3 the inside of the from half of the filter holder. Brush and rinse each surface three times or more, if needed, to remove visible sample matter. Make a final rinse of the brush and filter holder. After all 0.1 N HNO3 washings and sample matter are collected in the sample container, tighten the lid on the sample container so that the fluid will not leak out when it is shipped to the laboratory. Mark the height of the fluid level to determine whether leakage occurs during transport. Label the container to identify its contents clearly.

8.7.2 Container No. 3 (Silica Gel).

Note the color of the indicating silica gel to determine if it has been completely spent, and make a notation of its condition. Transfer the silica gel from the fourth impinger to the original container, and seal. A funnel may be used to pour the silica gel from the impinger and a rubber policeman may be used to remove the silica gel from the impinger. It is not necessary to remove the small amount of particles that may adhere to the walls and are difficult to remove. Since the gain in weight is to be used for moisture calculations, do not use any water or other liquids to transfer the silica gel. If a balance is available in the field, follow the procedure for Container No. 3 in Section 11.4.2.

8.7.3 Container No. 4 (impingers).

Due to the large quantity of liquid involved, the impinger solutions may be placed in several containers. Clean each of the first three impingers and connecting glassware in the following manner:

Wipe the impinger ball joints free of silicone grease, and cap the joints.

Rotate and agitate each impinger, so that the impinger contents might serve as a rinse solution.

Transfer the contents of the impingers to a 500-ml graduated cylinder. Remove the outlet ball joint cap, and drain the contents through this opening. Do not separate the impinger parts (inner and outer tubes) while transferring their contents to the cylinder. Measure the liquid volume to within 2 ml. Alternatively, determine the weight of the liquid to within 0.5 g. Record in the log the volume or weight of the liquid present, along with a notation of any color or film observed in the impinger catch. The liquid volume or weight is needed, along with the silica gel data, to calculate the stack gas moisture content (see Method 5, Figure 5-6).

Transfer the contents to Container No. 4.

NOTE: In Sections and, measure and record the total amount of 0.1 N HNO3 used for rinsing.

Pour approximately 30 ml of 0.1 N HNO3 into each of the first three impingers and agitate the impingers. Drain the 0.1 N HNO3through the outlet arm of each impinger into Container No. 4. Repeat this operation a second time; inspect the impingers for any abnormal conditions.

Wipe the ball joints of the glassware connecting the impingers free of silicone grease and rinse each piece of glassware twice with 0.1 N HNO3; transfer this rinse into Container No. 4. Do not rinse or brush the glass-fritted filter support. Mark the height of the fluid level to determine whether leakage occurs during transport. Label the container to identify its contents clearly.

8.8 Blanks.

8.8.1 Nitric Acid.

Save 200 ml of the 0.1 N HNO3 used for sampling and cleanup as a blank. Take the solution directly from the bottle being used and place into a glass sample container labeled "0.1 N HNO3blank."

8.8.2 filter.

Save two filters from each lot of filters used in sampling. Place these filters in a container labeled "filter blank."

9.0 Quality Control.

9.1 Miscellaneous Quality Control Measures. Section

9.2 Volume metering System Checks. Same as Method 5, Section 9.2.

10.0 Calibration and Standardizations.

NOTE: Maintain a laboratory log of all calibrations.

10.1 Sampling equipment.

Same as Method 5, Section 10.0.

10.2 Spectrophotometer.

10.2.1 Measure the absorbance of the standard solutions using the instrument settings recommended by the spectrophotometer manufacturer.

Repeat until good agreement (±3 percent) is obtained between two consecutive readings. Plot the absorbance (y-axis) versus concentration in g Pb/ml (x-axis). Draw or compute a straight line through the linear portion of the curve. Do not force the calibration curve through zero, but if the curve does not pass through the origin or at least lie closer to the origin than ±0.003 absorbance units, check for incorrectly prepared standards and for curvature in the calibration curve.

10.2.2 To determine stability of the calibration curve, run a blank and a standard after every five samples, and recalibrate as necessary.

11.0 Analytical Procedures.

11.1 Sample Loss Check.

Prior to analysis, check the liquid level in Containers Number 2 and Number 4. Note on the analytical data sheet whether leakage occurred during transport. If a noticeable amount of leakage occurred, either void the sample or take steps, subject to the approval of the Administrator, to adjust the final results.

11.2 Sample Preparation.

11.2.1 Container No. 1 (filter).

Cut the filter into strips and transfer the strips and all loose particulate matter into a 125-ml Erlenmeyer flask. Rinse the Petri dish with 10 ml of 50 percent HNO3 to ensure a quantitative transfer, and add to the flask.

NOTE: If the total volume required in Section 11.2.3 is expected to exceed 80 ml, use a 250-ml flask in place of the 125-ml flask.

11.2.2 Containers No. 2 and No. 4 (Probe and impingers).

Combine the contents of Containers No. 2 and No. 4, and evaporate to dryness on a hot plate.

11.2.3 Sample Extraction for Lead. on the approximate stack gas particulate concentration and the total volume of stack gas sampled, estimate the total weight of particulate sample collected. Next, transfer the residue from Containers No. 2 and No. 4 to the 125-ml Erlenmeyer flask that contains the sampling filter using a rubber policeman and 10 ml of 50 percent HNO3 for every 100 mg of sample collected in the train or a minimum of 30 ml of 50 percent HNO3, whichever is larger. Place the Erlenmeyer flask on a hot plate, and heat with periodic stirring for 30 minutes at a temperature just below boiling. If the sample volume falls below 15 ml, add more 50 percent HNO3. Add 10 ml of 3 percent H2O2, and continue heating for 10 minutes. Add 50 ml of hot (80C, 176F) water, and heat for 20 minutes. Remove the flask from the hot plate, and allow to cool. filter the sample through a Millipore membrane filter, or equivalent, and transfer the filtrate to a 250-ml volumetric flask. Dilute to volume with water.

11.2.4 filter Blank.

Cut each filter into strips, and place each filter in a separate 125-ml Erlenmeyer flask. Add 15 ml of 50 percent HNO3, and treat as described in Section 11.2.3 using 10 ml of 3 percent H2O2 and 50 ml of hot water. filter and dilute to a total volume of 100 ml using water.

11.2.5 Nitric Acid Blank, 0.1 N.

Take the entire 200 ml of 0.1 N HNO3 to dryness on a steam bath, add 15 ml of 50 percent HNO3, and treat as described in Section 11.2.3 using 10 ml of 3 percent H202and 50 ml of hot water. Dilute to a total volume of 100 ml using water.

11.3 Spectrophotometer Preparation.

Turn on the power; set the wavelength, slit width, and lamp current; and adjust the background corrector as instructed by the manufacturer's manual for the particular atomic absorption spectrophotometer. Adjust the burner and flame characteristics as necessary.

11.4 Analysis.

11.4.1 Lead Determination.

Calibrate the spectrophotometer as outlined in Section 10.2, and determine the absorbance for each source sample, the filter blank, and 0.1 N HNO3 blank. Analyze each sample three times in this manner. Make appropriate dilutions, as needed, to bring all sample Pb concentrations into the linear absorbance range of the spectrophotometer. Because instruments vary between manufacturers, no detailed operating instructions will be given here. Instead, the instructions provided with the particular instrument should be followed. If the Pb concentration of a sample is at the low end of the calibration curve and high accuracy is required, the sample can be taken to dryness on a hot plate and the residue dissolved in the appropriate volume of water to bring it into the optimum range of the calibration curve.

11.4.2 Container No. 3 (Silica Gel).

This step may be conducted in the field. Weigh the spent silica gel (or silica gel plus impinger) to the nearest 0.5 g; record this weight.

11.5 Check for Matrix Effects.

Use the Method of Standard Additions as follows to check at least one sample from each source for matrix effects on the Pb results:

11.5.1 Add or spike an equal volume of standard solution to an aliquot of the sample solution.

11.5.2 Measure the absorbance of the resulting solution and the absorbance of an aliquot of unspiked sample.

11.5.3 Calculate the Pb concentration Cm in g/ml of the sample solution using Equation 12-1 in Section 12.5. Volume corrections will not be required if the solutions as analyzed have been made to the same final volume. Therefore, Cm and C>a represent Pb concentration before dilutions. Method of Standard Additions procedures described on pages 9-4 and 9-5 of the section entitled "General Information" of the Perkin Elmer Corporation Atomic Absorption Spectrophotometry Manual, Number 303-0152 (Reference 1 in Section 17.0) may also be used. In any event, if the results of the Method of Standard Additions procedure used on the single source sample do not agree to within ±5 percent of the value obtained by the routine atomic absorption analysis, then reanalyze all samples from the source using the Method of Standard Additions procedure.

12.0 Data Analysis and Calculations.

12.1 Nomenclature.

12.2 Average console meter temperatures (Tm) and Average Orifice Pressure Drop (H).

See data sheet (Figure 5-3 of Method 5).

12.3 Dry Gas Volume, Volume of Water Vapor, and Moisture Content.

Using data obtained in this test, calculate Vm(std), Vw(std), and Bws according to the procedures outlined in Method 5, Sections 12.3 through 12.5.

12.4 Total Lead in Source Sample.

For each source sample, correct the average absorbance for the contribution of the filter blank and the 0.1 N HNO3 blank. Use the calibration curve and this corrected absorbance to determine the Pb concentration in the sample aspirated into the spectrophotometer. Calculate the total Pb content mt(in g) in the original source sample; correct for all the dilutions that were made to bring the Pb concentration of the sample into the linear range of the spectrophotometer.

12.5 Sample Lead Concentration.

Calculate the Pb concentration of the sample using the following equation:

12.6 Lead Concentration.

Calculate the stack gas Pb concentration Cs using Equation 12-2:


12.7 Stack Gas Velocity and Volumetric flow Rate.

Calculate the average stack gas velocity and volumetric flow rate using data obtained in this method and the equations in Sections 12.2 and 12.3 of Method 2.

12.8 Isokinetic Variation.

Same as Method 5, Section 12.11.

13.0 Method Performance.

13.1 Precision.

The within-laboratory precision, as measured by the coefficient of variation, ranges from 0.2 to 9.5 percent relative to a run-mean concentration. These values were based on tests conducted at a gray iron foundry, a lead storage battery manufacturing plant, a secondary lead smelter, and a lead recovery furnace of an alkyl lead manufacturing plant. The concentrations encountered during these tests ranged from 0.61 to 123.3 mg Pb/m3.

13.2 Analytical Range.

For a minimum analytical accuracy of ±10 percent, the lower limit of the range is 100 g. The upper limit can be extended considerably by dilution.

13.3 Analytical Sensitivity.

Typical sensitivities for a 1-percent change in absorption (0.0044 absorbance units) are 0.2 and 0.5 g Pb/ml for the 217.0 and 283.3 nm lines, respectively.

14.0 Pollution Prevention. [Reserved]

15.0 Waste Management. [Reserved]

16.0 Alternative Procedures.

16.1 Simultaneous Determination of Particulate and Lead Emissions.

Method 5 may be used to simultaneously determine Pb provided: (1) acetone is used to remove particulate from the Probe and inside of the filter holder as specified by Method 5, (2) 0.1 N HNO3 is used in the impingers, (3) a glass fiber filter with a low Pb background is used, and (4) the entire train contents, including the impingers, are treated and analyzed for Pb as described in Sections 8.0 and 11.0 of this method.

16.2 filter Location.

A filter may be used between the third and fourth impingers provided the filter is included in the analysis for Pb.

16.3 In-Stack filter.

An in-stack filter may be used provided: (1) a glass-lined Probe and at least two impingers, each containing 100 ml of 0.1 N HNO3after the in-stack filter, are used and (2) the Probe and impinger contents are recovered and analyzed for Pb. Recover sample from the probe nozzle with acetone if a particulate analysis is to be made.

17.0 References.

Same as Method 5, Section 17.0, References 2, 3, 4, 5, and 7, with the addition of the following:

1. Perkin Elmer Corporation. Analytical Methods for Atomic Absorption Spectrophotometry. Norwalk, Connecticut. September 1976.

2. American Society for Testing and Materials. Annual Book of ASTM Standards, Part 31: Water, Atmospheric Analysis. Philadelphia, PA 1974. p. 40-42.

3. Kelin, R., and C. Hach. Standard Additions—Uses and Limitations in Spectrophotometric Analysis. Amer. Lab. 9:21-27. 1977.

4. Mitchell, W.J., and M.R. Midgett. Determining Inorganic and Alkyl Lead Emissions from Stationary Sources. U.S. Environmental Protection Agency. Emission Monitoring and Support Laboratory. Research Triangle Park, NC. (Presented at National APCA Meeting, Houston. June 26, 1978).

18.0 Tables, Diagrams, flowcharts, and Validation Data.

Figure 12-1. Inorganic Lead Sampling Train.

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