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Mr. Robert Small
Commonwealth of Pennsylvania
Department of Environmental Protection
P.O. Box 8468
Harrisburg, PA 17105-8468

Dear Mr. Small:

I am writing in response to a request from Mr. Joseph Grau of Monarch Analytical Laboratories to the U.S. Environmental Protection Agency (EPA), Office of Air Quality Planning And Standards (OAQPS) for review of performance data demonstrating compliance with the National Emission Standards for Chromium Emissions From Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks ("Chrome Plating NESHAP"; 40 CFR Part 63, subpart N).

Monarch Analytical Laboratories performed two sets of performance compliance tests (July 1997 and November 1997) for the measurement of hexavalent chromium being emitted from a chrome plating operation and controlled by a MAPCO Enforcer III scrubber. The plating operation is located at the Techneglas Television Products, Inc. facility in Pittston, PA; Permit No. 40-318-031A.

As I understand, the first performance test was performed to determine the compliance for the chrome plating scrubber in July 1997 and the emission data submitted to the Department of Environmental Protection (DEP), Commonwealth of Pennsylvania. The scrubber compliance data were rejected because they did not meet the minimum sample requirements (33 micrograms Cr+6 per run) for the California Air Resources Board (CARB) Method 425. As you know, EPA has determined CARB Method 425 to be an approved alternative method for demonstrating chromium concentrations from hard and decorative chromium electroplating and anodizing tanks if the following conditions are met:

  1. if the colormetric analysis method is used, the sampling time and volume shall be sufficient to provide 33 to 66 micrograms of Cr+6 in the sampling train.
  2. if atomic absorption graphite furnace (AAGF) or post-column reactor (ICPCR) analyses is used, the sampling time and volume shall be sufficient to result in a Cr+6 sample catch that is 5 to 10 times the minimum detection limit of the analytical method; i.e., 1.0 microgram Cr+6 per liter of sample for AAGF and 0.5 microgram Cr+6 per liter of sample for ICPCR.
  3. a minimum of three separate runs must be conducted. For the three July 97 compliance runs, the Method 425 colormetric analysis measured 10.9 µg Cr+6 for Run 1, 13.7 µg Cr+6 for Run 2, and 13.4 µg Cr+6 for Run 3, respectively. The Cr+6 sample concentrations calculated from these results were 0.0095 mg/dscm for Run 1, 0.0119 mg/dscm for Run 2, and 0.0120 mg/dscm for Run 3. As per the analytical method, the Cr+6 totals were determined for each run by adding the results of two separate analyses that measured the Cr+6 content for: 1) the probe fraction and 2) the impinger/filter fraction.

The range for the Method 425 colormetric analysis is reported to be 0.5 to 50 µg/mL, provided that residuals are less than 10 percent. For a minimum analytical accuracy of 100 + 10%, the lower limit of the analytical range is 2 µg Cr+6/100 mL sample. The probe fraction measurements (0.7 µg Cr+6/100 mL , ND, and 0.7 µg Cr+6/100 mL) were well below this range. However, the impinger/filter fraction measurements of 2.2 µg Cr+6/100 mL, 3.6 µg Cr+6/100 mL, and 3.0 µg Cr+6/100 mL, respectively were within the minimum acceptance criteria. As you can see, the July performance Cr+6 analytical measurements are at best marginal when comparing them to the acceptance criteria recommended in Method 425. The measurements are not acceptable when compared to the minimum criteria of 33 micrograms per sample train listed in the Chrome Plating NESHAP regulation.

I have also reviewed the second scrubber emission test report that summarizes the data from a performance test conducted in November, 97 at the very same location. Again, three compliance runs were performed during the test and the Cr+6 samples were measured using the Method 425 colormetric analysis. However, the tester elected to perform Run 1 for 120 minutes and Runs 2 and 3 for 90 minutes each. For each of the three runs, the probe rinse and 1st impinger contents were combined and analyzed as one Cr+6 fraction and the second impinger contents was analyzed as a separate Cr+6 fraction. Note: There is no mention as to how the filter extract was combined. This combining of sample fractions (probe and 1st impinger) is not allowed in Method 425 (Section 13.0 Recovery Procedure). The method recommends that if sample dilution is a concern, which it is in this case, that three separate fractions: 1) probe rinse, 2) 1st impinger contents, and 3) 2nd impinger contents be collected and analyzed separately (3 separate analyses). The filter is to be added to the impinger fraction expected to have the higher Cr+6 concentration, which is usually the 1st impinger.

The other difference noticed was that the November, 97 total reagent recovery volumes were much less as compared to the July, 97 test:

The July separate probe rinse volumes (1st impinger not included) were 300 mL, 290 mL, and 200 mL, respectively. The July impinger contents (1st and 2nd units combined) were 300 mL, 380 mL, and 400 mL, respectively. Method 425 recommends that ~100 mL of reagent be used to rinse the probe and a maximum of ~200 mL of reagent be used in the two impingers.

The November probe rinse and 1st impinger contents combined volumes were 148 mL, 214 mL, and 158 mL, respectively. The November impinger contents (2nd impg. only) were 104 mL, 104 mL, and 102 mL, respectively. The use of impinger washes were mentioned in the report. Method 425 does not require impinger rinses as they dilute the sample. Evidently, the tester believed that the sample concentration could be increased by combining the probe rinse and 1st impinger fractions while reducing the reagent recovery volumes.

For the November, 97 compliance runs, the Method 425 colormetric analysis measured 11.4 µg Cr+6 for Run 1, 6.8 µg Cr+6 for Run 2, and 13.1 µg Cr+6 for Run 3, respectively. The Cr+6 sample concentrations calculated from these results were 0.0083 mg/dscm for Run 1, 0.0066 mg/dscm for Run 2, and 0.0123 mg/dscm for Run 3. In contrast to the analytical method directions, the Cr+6 totals were determined for each run by adding the results of two separate analysis that measured the Cr+6 content for: 1) the probe and 1st impinger combined fractions and 2) the 2nd impinger fraction. There is no mention of the filter analysis.

Again, the lower limit of the analytical range is 2 µg Cr+6/100 mL sample. The November probe/1st impinger fraction measurements of 6.7 µg Cr+6/100 mL , 2.5 µg Cr+6/100 mL, and 7.5 µg Cr+6/100 mL, respectively were within the range of the analytical method as were most of the 2nd impinger fraction measurements of 2.5 µg Cr+6/100 mL, 7.5 µg Cr+6/100 mL, and 1.4 µg Cr+6/100 mL, respectively. The November performance test Cr+6 analytical measurements meet the minimum acceptance criteria of Method 425. They do not meet the minimum acceptance criteria of 33 micrograms per sample train listed in the Chrome Plating NESHAP regulation.

While reviewing the two emission test reports, I noticed several problems and/or technical deficiencies for which I have summarized in the following:

  1. A performance pretest plan along with a continuous compliance monitoring plan, a list of work practices, and an operation and maintenance plan should have been submitted to the enforcement authority for review and approval, prior to the test being conducted.
  2. The enforcement authority should have been notified 60 days in advance of the performance test.
  3. The sample time/volume should be increased to meet the minimum requirements of the analytical method and the Chrome Plating NESHAP regulation, or either the AAGF analytical method or the IC/PCR analytical method should have been selected instead.
  4. The teflon sample line should not have been used on a train of this type as it is very difficult to recover the Cr+6 without using excessive amounts of reagent which dilute the sample fraction. The teflon tube should have been rinsed and soaked at least three times with adequate volumes of 0.1N NaOH and the rinses added to the probe rinse fraction.
  5. The probe reagent rinse volume should have been limited to ~100 mL per Method 425 and recovered separate of the impinger fractions.
  6. The impingers solution should have been limited to ~200 mL total volume and sample recovery should have been per the method to minimize sample dilution. Method 425 requires separate analysis for each of the impinger fractions. The filter extract should be added to one of the impinger fractions.
  7. The July field blank reagent was very high. Ultra grade reagents should have been used to prepare the field reagents.
  8. The pH of the probe rinse and 1st impinger solution should have been checked and recorded prior to sample recovery to verify that the pH was maintained at >8.0 and no conversion of Cr+6 occurred.
  9. The field samples should have been maintained at < 10C during storage and shipping.

In conclusion, after reviewing the July test data in detail, as well as the data from the second performance test (November, 97) at the same location, I am in agreement with the Pennsylvania DEP assessment that the performance results are unacceptable as conducted. However, I do believe that if properly sampled, using the correct procedures, it could be demonstrated that the facility is meeting its regulatory emission limit.

There is no excuse for the tester not collecting sufficient sample for the colormetric analysis during the November 97 performance test. Data were available from the July test that provided the Cr+6 stack concentrations required to determine the required sample volume and time. The tester could have either collected sufficient sample volumes, or selected an analysis method with a lower detection limit that would meet the regulatory acceptance limit.

The technical mistakes made during the sampling program probably influenced the results somewhat, however, they would have not double the Cr+6 content.

The reports do not state if the teflon tube was rinsed and where the rinse was placed. Very small quantities of Cr+6 were probably not removed from the tube. If the tube was rinsed, the rinse reagent would have added to the dilution problem of the sample fraction.

Too much reagent was used during the July test and the combined reagent rinses for two runs during the November test are less than what is specified in the method (probe plus the teflon tube, 100 mL and 1st Impg 100 mL). These volumes have a direct effect on the Cr+6 sample recovery and dilution factor.

The July test showed a reagent field blank value of 10 µg Cr+6/L which is high.

There is no mention that the pH of the test solutions were checked after the test. Since Cr+6 is the target analyte it is important that the pH be maintained at >8.0 to assure that no conversion occurs.

There is no record of sample conditioning during storage and/or shipping. Cr+6 samples should be maintained at < 10C or lower until received at the laboratory.

In summary, since a number of problems associated with the two performance tests have been identified, we agree with the Department of Environmental Protection, Commonwealth of Pennsylvania that the results of the performance test are not are not acceptable.

Questions regarding this correspondence should be directed to Mr. Clyde E. Riley, U.S. Environmental Protection Agency, Mail Drop 19, Research Triangle Park, North Carolina 27711, Telephone No. (919) 541-5239.

Sincerely,

Clyde E. Riley
Emission Measurement Center


cc: William Lamason, EPA, OAQPS/EMAD (MD-19)
Robin Segall, EPA, OAQPS/EMAD (MD-19)
Lalit Banker, EPA, OAQPS/ESD (MD-13)
Phil Mulrine, EPA OAQPS/ESD (MD-13)
Scott Throwe, EPA, OECA
James Kenney, EPA Region III



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