Questions for Miami Fort

Arsenic

1. Confirm 200.8 self-monitoring data used a collision cell or dynamic reaction cell.

2. Why is the RL for the 200.8 self-monitoring data at 20 ug/L or higher? 

a. Why not analyze samples to achieve lower RLs, given that clearly was possible (see EPA 

and industry results for dates of EPA sampling and 308 sampling)?

b. Why was the plant/lab able to measure at low enough levels to report a detect at 4.34 

ug/L on 6/28/11, but weeks preceding and following are all ND at 20 ug/L? (Also note 

that the RL is listed as 20 ug/L on that date.)

3. Why are there multiple results for each day on 7/13/10, 7/14/10, 7/15/10, 7/16/10, 9/28/10, 

11/2/10, 12/7/10, & 1/14/11? Would it be appropriate to average the results for each day to 

obtain a single daily value? 

4. Please explain the observations reported for 5/8/13 (5, 5, 46, and 500 ug/L). Clarify which 

results are D or ND (inconsistency between comments and the data table).

5. Please provide the lab reports for the arsenic data in the “USEPA Analytical Data Table MFS #-

26_14.xlsx” file for the following dates (these reports were not included in the disk): 7/13/2009, 

8/3/2009, 9/1/2009, 10/5/2009, 11/2/2009, 12/1/2009, 1/5/2010, 2/2/2010, 3/2/2010, 

4/6/2010, 5/4/2010, 6/1/2010, 7/6/2010, 7/12/2010, 7/13/2010, 7/14/2010, 7/15/2010, 

7/16/2010, 8/3/2010, 9/7/2010, 9/28/2010, 10/5/2010, 11/2/2010, 12/7/2010, 1/14/2011, 

6/28/2011, 6/28/2011, 3/6/2012, 7/31/2012, 8/1/2012, 8/8/2012, 8/9/2012, and 5/8/2013.

Mercury

6. Confirm that data submitted by UWAG are repeats of the data reported by Duke (and not lab 

analyses of split samples)

7. Apparent data entry errors where the spreadsheet is offset by one day from the data previously 

submitted in comments by Duke and UWAG. Which date is correct? (See 8/3/09, 

8/4/09...10/1/09, 10/2/09...11/2/09, 11/3/09... 6/1/10, 6/2/10...7/1/10, 7/2/10...8/2/10, 

8/3/10...9/1/10, 9/2/10...10/4/10, 10/5/10...1/4/11, 1/5/11...3/1/11, 3/2/11...4/4/11, 

4/5/11...8/30/11, 9/2/11)

8. Why does the spreadsheet omit the following observations that were included in the Duke 

comments: 

a. 7/14/10 (120 ng/L)

b. 9/28/10 (242 ng/L)

c. 11/2/10 (251 ng/L). Note that the spreadsheet shows 343 ng/L on this date. Is the 343 

a data entry error? If not, please provide the lab report for this result.

9. Why does the spreadsheet show 43 ng/L on 5/24/11, compared to Duke & UWAG comments 

showing 20 ng/L? Is this actually the observation in Duke comments for 6/28/11? Note that 

there is no lab report for 6/28/2011, so is the 43 ng/L a data entry error?

10. Please confirm that for the FGD WWT effluent (Outfall 608), Duke Energy provided the average 

of two total mercury samples in the spreadsheet (i.e., average of native sample and duplicate). 

Based on a review of the lab reports, EPA found the following discrepancies:

a. The average value for 10/2/2009 should be 83.15 ng/L (instead of 84.95 ng/L).
b. The values provided for 1/3/2013, 7/2/2013, 10/2/2013, and 6/2/2011 for Outfall 608 

only account for the native sample and do not account for averaging the duplicate 

result. EPA believes the following values should be used:

i. 1/3/2013: 48 ng/L (instead of 50 ng/L);

ii. 7/2/2013: 245 ng/L (instead of 250 ng/L); and

iii. 10/2/2013: 265 ng/L (instead of 260 ng/L).

iv. 6/2/2011: 80.5 ng/L (instead of 79 ng/L). Additionally, in the analytical data 

table, the RL is reported as 0.5 ng/L and the dilution factor is reported as 1. 

However, in the lab report, the native and duplicate sample for Outfall 608 both 

have a RL of 10 ng/L and a dilution factor of 20. Which RL and dilution factor 

values are correct? 

11. See the observations on 7/2/13 (250 and 33). The lab report shows that the 33 ng/L result is for 

dissolved mercury (spreadsheet says total Hg); the total mercury value should be 245 ng/L 

(average of 240 and 250). (Also see 10.b.ii above)

12. The sample value for 4/2/2013 of 0.5 ng/L for the FGD WWT effluent (Outfall 608) is flagged as a 

non-detect value in the lab report but a detection in the data table. Please confirm whether this 

should be treated as a detected or non-detect value.

13. The value from 11/3/2009 for Outfall 608 is a rounded value. EPA believes the value should be 

262.5 ng/L (instead of 263 ng/L).

14. The 57.95 ng/L total mercury value reported for effluent 9/1/2009 should be 9/21/2009. The 

spreadsheet is missing the actual 9/1/2009 result of 62.7 ng/L.

15. The dilution factor and reporting limit (RL) for the Outfall 608 mercury data from 4/5/2011, 

8/4/2011, and 9/2/2011 are different for the native and duplicate sample. For the 4/5/2011 and 

8/4/2011 sample, Duke Energy provided the average analytical result but reported the RL and 

dilution factor for the native sample; but for the 9/2/2011 sample, Duke Energy provided the 

average analytical result but reported the RL and dilution factor for the duplicate sample. Please 

explain the reasoning for which RL and dilution factor were provided in the analytical data table.

16. Please explain why FGD WWT influent (Outfall 601) results for samples analyzed with the 

SWA846 7470A method were not included in the analytical data table.

17. What values should be used to represent the FGD WWT Influent (Outfall 601) on 8/3/2011? 

a. For Unit 7, the analytical data table includes 320,000 ng/L and includes a note from Joe 

Potts that value “was 300,000 TA reports show 320,000.” However, from EPA’s review 

of the lab report, there was one result using EPA Method 1631 at 300,000 ng/L and one 

result using Method 7470A at 360 ug/L. 

b. For Unit 8, the analytical data table includes 290,000 ng/L. EPA notes there are four 

results for Unit 8 total mercury:

i. Native sample using 1631E: 290,000 ng/L

ii. Duplicate sample using 1631E: 320,000 ng/L

iii. Native sample using 7470A: 410 ug/L

iv. Duplicate sample using 7470A: 420 ug/L

On the Table 1 summary of the lab report (see page 4 of PDF), there is a footnote 

designation for the 1631E Unit 8 samples stating that “after collection of samples, URS 

was informed that both Unit 7 and 8 were being processed through Station 601.” Which 

mercury results are most appropriate for use in representing the Unit 8 sample results?

18. The dilution factor for the FGD WWT Influent (Outfall 601) on 9/3/2013 for Units 7 and 8 are 

listed as 100,000 in the analytical data table, but the lab report shows the dilution factor as 100. 

Based on the reporting limit for the samples (20,000 ng/L) and the laboratory reporting limit for 
a dilution factor of 1 (0.5 ng/L), it seems that dilution factor should be 40,000. Which dilution 

factor is correct?

19. We observed three data points at substantially higher concentrations relative to the other 

effluent values. What was happening with plant processes, coal sources, treatment system 

operation? What actions were taken in response to these observed concentrations?

a. 9/1/10 (640.5)

b. 7/6/11 (675)

c. 10/4/11 (770)

20. Please provide the lab reports for the mercury data in the “USEPA Analytical Data Table MFS #-

26_14.xlsx” file for the following dates (these reports were not included in the disk): 9/21/2009 

(only summary page provided), 7/12/2010, 7/13/2010, 7/14/2010, 7/15/2010, 7/16/2010, 

12/7/2010, 1/5/2011, 1/14/2011, 2/1/2011, 9/26/2011, 3/1/2012, 7/31/2012, 8/1/2012, 

8/8/2012, 8/9/2012, 2/4/2013, 2/5/2013, 3/4/2013, 3/5/2013, 5/1/2013, 5/2/2013, 5/8/2013, 

6/3/2013, 6/4/2013, and 8/2/2013.