Hunton & Williams LLP •Counsel to UWAG • 1900 K Street, N.W. • Washington, D.C. 20006

Steering/Audit Committee

Angela M. Grooms, 

Chairman

C. Richard Bozek

Rayburn L. Butts

Alan E. Gaulke

M. R. (Mick) Greeson

David M. Lee

James F. Stine

John G. Valeri, Esq.

Kerry M. Whelan

Judson White

March 19, 2010 FILE NO.: 29142.070312

Mr. Ronald P. Jordan

U. S. EPA

Engineering & Analysis Division (4303T)

Ariel Rios Building

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

Mr. Richard W. Reding

U.S. EPA 

Ariel Rios Building (4303T)

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

UWAG Comments on EPA Draft Standard

Operating Procedure entitled “Inductively Coupled Plasma

Mass Spectrometry for Trace Element Analysis in

Flue Gas Desulfurization Wastewaters” dated February 12, 2010

Dear Ron and Dick:

The Utility Water Act Group (UWAG) is pleased to submit comments on the draft 

standard operating procedure (SOP) entitled “Inductively Coupled Plasma Mass Spectrometry 

for Trace Element Analysis in Flue Gas Desulfurization Wastewaters” dated February 12, 2010. 

UWAG’s comments, however, should be considered preliminary because UWAG has not yet 

had a chance to evaluate the accuracy of any FGD wastewater data produced using the draft 

SOP. Also, UWAG asked several questions at our March 11 meeting concerning the actual 

instrumental setup and procedures used to develop the draft SOP but we have not yet received 

specific answers to those significant questions. UWAG is anxious to provide a comprehensive 

review of the draft SOP but without the appropriate information about fundamental aspects of the 

draft SOP our ability to provide substantive and validating comments concerning the accuracy of 

data produced by the draft SOP is limited.

Our comments are organized into two sections. The first section deals with general 

comments that apply to the draft SOP as a whole. The second section includes specific 

comments on the individual sections of the draft SOP. 
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

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A. General Comments/Questions

1. The draft SOP, even though ostensibly developed specifically for FGD wastewater 

analysis, is quite generic and appears patterned largely after EPA method 200.8 with 

minimal modifications to accommodate FGD samples. Except for the use of a synthetic 

FGD wastewater (see note 2), very little information is given in the draft SOP that helps the 

analyst run FGD samples in a way that is different from running any other sample type. 

The draft SOP doesn’t even provide a description of the nature and analytical challenges 

posed by complex FGD matrices.

2. The primary SOP modification specific to FGD wastewaters appears to be the use of a 

“synthetic FGD wastewater” (SFGDWW, sections 7.2.7 and 9.4) to confirm the lack of 

uncontrolled interferences above the various elemental method reporting limits. The 

SFGDWW is also used to perform an annual matrix specific method detection limit study 

(section 12.1). The use of a SFGDWW is a good approach. However, the use of the 

SFGDWW should be expanded as follows to more fully evaluate potential enhancement or 

reduction of “real” element concentrations from a given CRC-ICP-MS instrumental setup:

a. The SFGDWW should be analyzed prior to initiating each FGD sample analysis run 

and not just once a quarter.

b. Each aliquot of SFGDWW analyzed should first be digested in the same manner as 

“normal” FGD wastewater samples. 

c. Additional SFGDWW performance parameter requirements should be given in the 

draft SOP. For example, when compared to the dilute acid method blank, the 

SFGDWW should not cause a reduction or enhancement in either the elemental 

signals or internal standards counts beyond some specified window such as 60-125%. 

The exact percentage window should be determined based on method validation data 

showing at what point the accuracy of the method is impacted. Corrective action(s) 

should be specified for when the percentage window requirement is not met.

d. A single spiked digested SFGDWW aliquot should also be run with spiking levels 

that are the same as the laboratory fortified blank (section 9.7). An acceptable 

percent recovery requirement should be specified such as the 70-130 %R used for 

MS/MSD (section 9.8). Corrective action(s) should be specified for when the percent 

recovery requirement is not met for one or more elements. For example, if the 

spiking shows an uncontrollable matrix interference for a given element then the 
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Mr. Richard W. Reding

March 19, 2010

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element is not appropriate for inclusion in the method. Leaving the element out of the 

draft SOP method is more appropriate than just flagging every sample as having a 

“matrix interference” for that element. See also note A.8.

3. UWAG was pleased to be asked by the EPA to analyze representative split samples as part 

of the EPA’s Collision Cell Inductively-Coupled Plasma Mass Spectrometry (CRC-ICPMS) method development and evaluation study. The draft SOP being reviewed here is a 

result of that study. To support the EPA CRC-ICP-MS method development study, 

UWAG developed a substantial confirming analysis data set based on the analysis of the 

split samples as summarized below:

a. Confirming analyses were performed on all twenty split samples also analyzed by the 

EPA’s contract laboratory to develop the draft SOP.

b. The closed vessel digestion procedure used by UWAG to prepare the split samples 

for analysis was essentially identical to the digestion method used by EPA’s contract 

laboratory and described in the draft SOP (section 10.2). 

c. Confirming analyses were performed on identical digestion splits data by five 

independent laboratories, all with experience analyzing FGD wastewaters.

d. Eighteen elements were measured in the split samples (i.e., Ag, Al, As, Ba, Be, Cd, 

Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Se, Tl, V, Zn). 

e. Confirming analyses were performed by at least four independent analytical methods 

including CRC-ICP-MS (the same method used by the EPA contract laboratory), 

high-resolution-ICP-MS, Dynamic Reaction Cell (DRC)-ICP-MS and ICP-Atomic 

Emission Spectrometry (EPA method 200.7). Selenium was confirmed by a fifth 

independent analytical method (i.e., hydride generation atomic fluorescence).

f. All confirming analyses were done in the blind. This is the standard approach used 

for all intercalibration exercises including those required by EPA and NELAC for 

laboratory accreditation. With the exception of Albion Environmental (AE) that 

performed the closed vessel digestion and prepared the digestion splits, none of the 

UWAG confirming analysis laboratories knew anything about the split samples 

except a unique sample ID and the estimated total dissolved solids (TDS) level to use 

in optimizing their analytical procedures. No inter-confirming analysis laboratory 
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Mr. Richard W. Reding

March 19, 2010

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communications were allowed until after each laboratory had submitted its final data 

report.

g. Selected split samples were also digested using four other digestion procedures 

(including the one described in EPA method 200.2 and 200.8) and analyzed to 

provide additional confirming analysis data.

UWAG believed that our confirming analysis data would be used by EPA to help validate 

the accuracy and efficacy of the EPA’s draft CRC-ICP-MS method. UWAG is anxious to 

share its confirming analysis data with EPA. However, UWAG believes that the 

appropriate approach is for both EPA and UWAG to share their respective data sets 

simultaneously at the same meeting. This approach preserves the blind inter-calibration 

approach used for UWAG’s confirming analysis study and insures that all data 

comparisons will be done without any a priori comparisons by either EPA or UWAG. 

Without such data comparisons, UWAG has no way of knowing if the draft SOP is capable 

of producing accurate metals data in FGD wastewater matrices. Before sharing and 

comparing data, EPA and UWAG should agree as to what will constitute acceptable 

agreement between the EPA and UWAG confirming analysis data. Since the draft SOP 

may be used for compliance monitoring, a relative percent difference of 15% would 

represent acceptable agreement between the two data sets. 

4. Both the EPA split sample data and the UWAG confirming analysis data sets should be 

included as an attachment to the draft SOP to provide labs with examples of results from 

the analysis of “real world” FGD wastewater samples using the CRC-ICP-MS 

methodology as well as other methods. Use Table 12 in EPA method 200.8 as an example 

of a possible format.

5. The draft SOP is vague and lacks the completeness and detail required to allow a “normal” 

analytical laboratory to set up the method for routine use. Examples of the lack of detail 

are given below. Additional omissions or lack of detail are included in the specific 

comments section B.

a. Was a “slug type” sample loop discrete sample introduction system (e.g., Agilent 

ISIS-DS) used to develop the draft SOP (see section 6.1)? If so, an explanation of 

why this approach was used and how the discrete sampler should be configured is 

important to include in the SOP. An explanation is also important because such 

additional cost add-ons will likely reduce the number of laboratories willing or able to 

implement the draft SOP.
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

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b. Was a high matrix interface (e.g., Agilent HMI aerosol dilution interface) used to 

develop the draft SOP? If so, an explanation of why this approach was used and how 

the HMI should be configured is important to include in the SOP. An explanation is 

also important because such additional cost add-ons will likely reduce the number of 

laboratories willing or able to implement the draft SOP. HMI systems require the 

instrument to be cleaned more often.

c. No expected method detection limits (MDL) or reporting limits (RL) are given in the 

draft SOP. EPA method 200.8 includes this information in Table 7 and method 1638 

includes this information in Table 1. Since both MDL (once a year) and instrument 

detection limit (IDL) studies are required in the SOP, expected MDL/RLs should be 

included to provide labs with an indication of what they should expect to achieve 

when the instrument is properly configured. 

d. No setup parameters are given for the collision cell (e.g., cell gas flows, etc.), plasma 

(e.g., power setting, gas flows) or spectrometer data acquisition (e.g., dwell times, 

etc.). Complete setup parameters should be provided in easy-to-read summary tables 

(as are provided in EPA method 200.8 Table 6) to facilitate a laboratory properly 

configuring the instrument for analyses using the draft SOP. As done in method 

200.8, it would be helpful to give specific information on the actual CRC-ICP-MS 

instrument used to develop the draft SOP.

e. The draft SOP lacks clean sampling and analysis procedures to allow a “normal” 

analytical laboratory to more easily adopt procedures needed to consistently obtain 

accurate data at the low concentrations of which DRC-ICP-MS is generally capable. 

Use EPA method 1669 sections 4.1, 4.2 and 8 as an example of the necessary 

sampling contamination procedures. Use EPA method 1638 sections 4.1, 4.2 and 4.3 

as an example of the necessary analytical contamination control procedures.

6. It appears from the draft SOP that all split sample FGD wastewaters were analyzed 

undiluted by the EPA contract laboratory. If so, an explanation of why this approach was 

used should be given. Alternatively, perhaps such a dilution is accomplished through the 

use of a combination of the ISIS/HMI add-ons (if used). EPA method 200.8 (sections 1.3 

and 4.1.4) recommends that elevated TDS samples be diluted to a TDS level of < 2,000 

ppm prior to analysis.

7. The draft SOP (section 12.4) suggests that FGD wastewater samples may be quantified 

based on Linear Dynamic Range (LDR) and not the high calibration standard of 100 ppb 
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March 19, 2010

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(Attachment 8). Is this true? If so, then such an extrapolation with FGD matrices would 

appear to be non-optimal because the LDR is determined using single element ideal matrix 

standards (section 9.5). For example, EPA method 200.8 (section 1.1) states that “ ... linear 

working ranges will be dependent on the sample matrix, ...”. Using a LDR determined 

using dilute acid standards to extrapolate concentrations above the high calibration standard 

for undiluted high TDS matrices such as FGD wastewater could be problematic. The draft 

SOP wording should be changed to require sample dilution so that quantification occurs 

only at or below the highest calibration standard.

8. It appears from the draft SOP (section 9.8) that failed MS/MSD’s are only R-Flagged as 

matrix specific interference suspected if all other QC criteria are acceptable. There was 

some confusion during our March 11 meeting on this point. More effort to resolve such 

matrix specific interferences (e.g., dilution and re-analysis) should be incorporated into the 

draft SOP. Also, with such highly variable matrices as FGD wastewaters, a matrix specific 

MS/MSD requirement (i.e., perform a MS/MSD on each unique FGD wastewater matrix as 

is used in EPA method 1631E section 9.3 and EPA method 1631E implementation 

guidance chapter 5) should be added to the draft SOP. UWAG’s split sample confirming 

analysis data showed the presence of matrix specific interferences for selenium. The 

matrix specific MS/MSD requirement would be an addition to the 10% batch specific 

requirement currently in the draft SOP (section 9.8). If this is not done then one can 

envision the case where a failed batch specific MS/MSD would invalidate all affected data 

in the batch (i.e., the other 9 unspiked samples). Finally, a statement should be 

incorporated into the draft SOP (as is present in EPA method 1631E section 9.3.4.2) that 

data associated with a failed MS/MSD “may not be reported or used for permitting or 

regulatory compliance purposes.” 

9. The draft SOP specifies fixed concentration (40 ppb) pre-digestion spikes (Attachment 8) 

for all elements except aluminum. This approach is patterned after EPA method 200.8 and 

works for aqueous samples with low metal concentrations. However, this approach needs 

to be modified for FGD wastewaters which often contain elevated concentrations (> 200 

ppb) of several elements including selenium, manganese, nickel and zinc. For example, for 

most FGD wastewaters with elevated selenium concentrations, the 40 ppb spiking level 

will be too low and the spike signal will be buried in the unspiked sample signal. For 

example, the average selenium concentration from this 20 split sample study is 1,240 parts 

per billion (ppb). If the FGD wastewaters are run undiluted (see note 4), then the predigestion spiking level of 40 ppb would be only ~ 3% of the unspiked concentration and 

would be lost in the analytical noise. Based on EPA method 200.8 (section 9.4.3) this 
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March 19, 2010

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invalid (low) spike would just be ignored and the ability to identify any matrix specific 

interferences would be lost. This approach is inappropriate for an SOP specifically aimed 

at FGD wastewater analyses where selenium is an element of special interest. The draft 

SOP MS/MSD approach should be modified to require pre-screening analysis of FGD 

samples so that the spiking levels can be adjusted to allow valid spikes (i.e., 1-5 times the 

unspiked concentration) for higher concentration elements such as selenium. 

10. Most laboratories with experience using CRC-ICP-MS for FGD wastewater analysis prefer 

the use of hydrogen as the cell gas for selenium analysis. The draft SOP recommends the 

use of He although the SOP mentions H2 as an optional gas. The draft SOP should explain 

why He is used over H2, and should also provide information on the procedures used to 

optimize cell configuration (e.g., gas flow rates, etc.) for FGD wastewaters.

11. Even though CRC-ICP-MS is capable of detecting sub-ppb metal concentrations, both the 

draft SOP and method 200.8 (upon which the draft SOP appears to be based) are essentially 

silent on the need for clean metals sampling and analysis procedures to support such low 

MDL’s. Method 200.8 mentions the need for field blanks (section 8.5) but only in passing 

with no specific instructions on collection or evaluation. The draft SOP should be modified 

to include the following clean metals information to make labs explicitly aware of what is 

required to consistently achieve low MDL’s without significant contamination bias. The 

draft SOP should make it clear that clean metals procedures are needed during both sample 

collection and sample analysis to consistently produce accurate data:

a. Clean sampling contamination control procedures patterned after sections 4.1, 4.2 and 

8 in EPA method 1669.

b. Clean analysis contamination control procedures patterned after sections 4.1, 4.2 and 

4.3 in EPA method 1638. The use of pre-cleaned sample tubes and pump tubing are 

especially important to maintaining low method blanks. 

12. There are inconsistencies throughout the draft SOP concerning matching the acid matrix of 

samples and standards. EPA methods, including 200.8, typically use the same acid strength 

in the calibration standards and the samples. The draft SOP uses 2% nitric acid in the 

calibration standards, spiking stock solution, blank matrix, tuning solution, etc. However, 

the samples are digested (section 10.3) using 1% nitric acid. The strength of hydrochloric 

acid (0.5%) is consistent throughout the draft SOP. Was this difference for nitric acid 

intentional? If so an explanation of the decision not to matrix match nitric acid in standards 

and samples should be given.
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

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B. Specific Comments/Questions

Sec. # Comment/Question

2.2 The wording is awkward. Ions are not sorted, they are separated from one another. What 

is a “channel” electron multiplier? 

2.3 A brief description of how the collision cell actually removes molecular ion and other 

interferences should be added here for clarity. For example, the use of kinetic energy 

discrimination should be described.

3.3, 3.4 Definitions for “total metals” and “total recoverable metals” seem redundant. The 

digestion procedure described in the draft SOP (section 10.2) is basically the closed vessel, 

in-bottle dilute acid alternate digestion procedure described in EPA method 1638. The 

method 1638 digestion procedure is a “total recoverable” digestion. The definition of “total 

metals” should be deleted or revised to show more clearly why it is different than the total 

recoverable digestion and how and why the total metals definition applies to the draft SOP.

3.5 Should point to section 12.3, not 12.2. Also a definition of IDL should be given here and 

not just a reference. For example, EPA method 1638 defines Instrument Detection Limit 

(IDL) as “The concentration equivalent to the analyte signal which is equal to three times 

the standard deviation of a series of ten replicate measurements of the calibration blank 

signal at the selected analytical mass(es).”

3.7 Remove the underscore after “Solution”. On most ICP-MS’s the tuning solution is used to 

calibrate the mass filter. Perhaps the tuning solution is used differently on the CRC-ICPMS instrument used to develop the draft SOP (e.g., HP/Agilent 7XXX). For example, is 

the tuning solution used to calibrate the complex lens system on the Agilent and also 

optimize the torch position? A better description is needed so the end user laboratory 

knows what’s being adjusted.

3.10 The wording is incomplete. The LFB is also used to “... and to verify method performance 

(control) in an ideal sample matrix.”

3.11 The wording is incomplete. There is no mention of the reason for or use of a reagent blank. 

Should add something like “are used to determine the concentration of trace metals in the 

reagents that are used to prepare and analyze the samples. For this Method, reagent blanks 

are required for each new batch of reagents used.”
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

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Sec. # Comment/Question

3.12 The wording is misleading. The calibration blank is not equivalent to the ICB and CCB. 

They may have the same composition, but they are different and serve different purposes. 

For example, the calibration blank is used to set the zero point for the calibration curve and 

the CCB is used to monitor the level of carryover or contamination during an analytical 

run. 

3.13 The definition given is for a method detection limit not a method reporting limit. A 

definition for method reporting limit should be added to the draft SOP glossary.

4.2 The wording is confusing. It is not correct to say that “isobaric molecular interferences are 

caused by ions consisting of more than one atom or charge”; more than one atom means 

molecular, as in ArCl. A doubly charged ion can have (can, not must) only one atom, as in 

Ba++. Should include the description that such interferences “have the same nominal 

mass-to-charge ratio as the isotope of interest, and which cannot be resolved by the mass 

spectrometer in use.”

4.3 For clarity add the units to raw signal intensity (e.g., counts per second, total counts, etc.). 

Also, this section should mention that matching the element and internal standard 

ionization potential can be an important consideration in addition to the masses. 

6.1 A more complete description of the discrete sample introduction system (SIS) used to 

develop the draft SOP should be given. Is it the Agilent ISIS-DS? Also detailed setup 

parameters for the discrete SIS should be included to make it easier for labs to replicate the 

proper ISIS configuration. Furthermore, if reducing sample analysis time is one of the 

goals of the method, then more details and emphasis needs to be placed on whether the 

signal being measured is transient or has plateau-ed and how to confirm and optimize this 

signal stabilization situation. See also note A.5.a and A.5.b.

6.2 This section should specify which gases are needed as liquid (high usage volume) and 

which gases can be used as compressed cylinders.

7.2.1 Refers to Attachment 5 not 9.

7.2.3 This section needs to provide enough information for a laboratory to easily make up or 

purchase the calibration standards. Need to clearly identify all custom standard mixes, etc. 

to avoid any confusion. For example, the elemental composition and concentrations (and 

acid strengths) of the custom multi-element mixes (presumably ICPMSCal-1, ICPMSCal2, 

ICPMSCal-3 and ICPMS-BRC have to be defined in a table. Remove double period after 

word “matrix”. Also, there is a reference to nonexistent Attachment 11. It is probably 

referring to attachment 8.
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

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Sec. # Comment/Question

7.2.6 Describe how the individual FGD interference check solutions are prepared (including acid 

matrix) or if they are purchased individually.

7.2.7 Describe how the synthetic FGD wastewater solution is prepared including acid matrix. 

Due to the high concentration of some elements is precipitation a problem? If so, how is 

precipitation avoided, etc. Why was fluoride added? Has it been quantified in FGD 

wastewaters?

7.2.7.1 We assume the chloride concentration is 15,000 mg/L not 15.0 mg/L.

7.2.8 Is the reference to ICV standards correct? (Plural?) This may not be a typo, because the 

following verb is “are”. Attachment 8 shows three calibration standards but it is not clearly 

specified. Also see note 7.2.3. The exact elemental composition and concentrations (and 

acid strengths) of the various mixed standards have to be clearly defined in a table so that a 

lab can easily recreate the necessary calibration standards. The designations here ICPMSTA, ICV A, etc., are different from those in 7.2.3. Do they refer to a second source of the 

same custom mixes? 

7.2.9 Is 3% nitric acid correct or should it be 2% or 1%? The bullet description is incomplete. 

What is the concentration? 50 ppb? Refers to a non-existent attachment 11 which is 

probably attachment 8.

7.2.10 The section references nonexistent Attachment 11 which is probably attachment 8.

8.0 This section should briefly describe the clean sampling procedures and then reference 

method 1669 where more detailed information can be obtained.

9.1 This section references nonexistent Attachment 11 which is probably attachment 8.

9.3 Manganese listed on the draft SOP is also monoisotopic.

9.4 ”Prior to initiating sample analysis” could be a one-time event or every day. The synthetic 

FGD wastewater solution should be run each day FGD wastewaters are analyzed. 

Manganese listed on the draft SOP is also monoisotopic.

9.5 Since this SOP describes a method optimized for FGD samples, why not use the synthetic 

FGD wastewater solution as the linear range sample? See also note A.7.

9.6 The acceptance criterion for the method blank appears to be an attempt to estimate the 

method reporting limit. Why not use the definition of method reporting limit used in 

previous EPA methods: “The ML is calculated by multiplying the MDL by 3.18 and 

rounding the result to the number nearest to (1, 2, or 5).”
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March 19, 2010

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Sec. # Comment/Question

9.7 This section should specify that “processed” means carrying the LCS through the entire 

sample preparation procedure just like a sample. Why is method 200.8 referred to in this 

section? Refers to non-existent attachment 12.

9.8 Simply flagging a failed MS/MSD should not be acceptable for this special method. The 

analyst should be required to dilute and re-analyze or modify the CRC-ICP-MS parameters 

to resolve the interference. If the failed MS/MSD cannot be resolved then all associated 

sample data should be rejected and flagged as not usable for compliance reporting 

purposes. See also note A.8. Refers to non-existent attachment 11 which is probably 

attachment 8.

9.9 Add the corrective procedure to follow if the instrument has drifted. Presumably, the 

analyst should stop analyses, recalibrate and re-analyze all affected samples.

10.2.8 Should heat for 2 hrs AFTER the sample temperatures have reached 85 deg. C.

10.3.1 Attachment(s) should be added showing all necessary instrument setup parameters to make 

it as easy as possible for another lab to implement the draft SOP procedure (see also note 

A.5). Tables 6 in method 200.8 can be used as a starting point. However other tables 

(attachment) should be added to cover all instrument setup as follows:

Additions to instrument setup parameters not included in Table 6:

Tuning mode = robust tuning option

RF matching should be included in the tuning of the instrument

P/A factor should be used at a 100x dilution from stock P/A factor solution (vendor) 

and the instrument should be rinsed for 10-min with 2.0% HNO3/0.5% HCl before 

calibrating the instrument

Spray chamber temperature (2 deg. C?)

Carrier gas flow = 0.99 L/min

Table X-1: Setup parameters for the ISIS-DS discrete sample introduction system (if 

used). Suggested parameters (by no means a complete list) would be sample 

loop volume, sample loop flow rate (pump speeds), nebulizer gas flow, flush 

and read delay (stabilization times) before data acquisition, post acquisition 

rinse out time (can be combined to next sample flush delay), etc.

Table X-2: Setup parameters for the HMI (if used). Suggested parameters (by no means 

a complete list) would be mostly related to gas flow rates and inspection or 
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March 19, 2010

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Sec. # Comment/Question

cleaning requirements.

Table X-3: Setup parameters for the collision cell. Suggested parameters (by no means a 

complete list) would be cell gas used, cell gas flow rate, QPBias and OctP 

Bias settings, stabilization time between gas modes, sequence of gas modes 

(e.g., H2 first then he then no gas), etc..

Table X-4: Data acquisition parameters for mass spectrometer. Suggested parameters (by 

no means a complete list) would be integration (dwell) times (seconds per 

point), number of replicates (typically 3), etc.

10.3.3 This may work for ArCl, but FGD samples have very high calcium (Ca) concentrations. 

This step should include Ca as well as Cl to ensure that erroneous As counts from CaCl2 

can be eliminated as well.

10.3.5 This references nonexistent Attachment 11 which is probably attachment 8. Refers to 

wrong section (7.2.4); should point to 7.2.8.

10.3.7 The intent of this section is unclear. This SOP is for CRC-ICP-MS analysis. This section 

seems to have been copied and pasted from EPA method 200.7 where two point 

calibrations can be used. No RL verification standard is listed in section 7.2.6. This 

section needs to be clarified or deleted depending on what is intended related to CRC-ICPMS analyses. It appears this may be the MDL solution referred to in section 12.

10.3.8 How many times can the CCV be reanalyzed before analysis is terminated?

10.4.2 The composition of the rinse blank must be specified probably in section 7.3.

10.4.3 Since this section should be critical in accurately analyzing some of the most challenging 

samples most labs have seen, there should be guidance and specific detail on what masses 

should be monitored and how the day to day analyst should decide whether given elements 

have been affected. As written this important requirement would be very difficult for most 

labs to implement. A good starting point would be Table 4 from EPA method 200.8. 

Attachment 4 should be revised to match Table 4 with mass 78 added for selenium, mass 

138 added for barium (if desired). All known interferants (e.g., calcium, potassium, etc.) 

for the elements of interest should also be added to Attachment 4 with identification to the 

element(s) affected. Also, a description of how to monitor multiple isotope masses by 

comparing the sample concentrations calculated for each isotope and then using perhaps the 

spiked synthetic FGD wastewater (see note A.2.d.), reference materials or known

interferants, etc. to determine which isotope to use for quantification in a given FGD 

matrix. This data inspection and evaluation is time consuming in the beginning but will 

become easier when the most reliable masses for quantifying FGD wastewaters by a given 
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March 19, 2010

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Sec. # Comment/Question

method are determined. However, a caveat must be included that because of the variability 

of FGD wastewaters no hard and fast rule can be given about the best isotope mass to use 

for all FGD wastewaters. There is no substitute for continually monitoring multiple masses 

and adjusting quantification strategies (i.e., isotope mass and internal standard) for a given 

batch of FGD wastewaters.

10.4.4 See note A.7. Samples with element concentration greater than the high calibration 

standard (100 ppb?) should be diluted and re-analyzed to fall below 100 ppb.

10.4.5 Shows only 1 calibration standard, although sections 7.2.4 and 10.3.4 both say that a blank 

and 3 calibration standards should be run. This section needs to be revised to describe how 

the calibration is performed.

11.3 Should specify how the “spike added” is calculated.

11.4 The RPD equation is incorrect; the denominator should show the sum, not the difference.

11.5 If the sample digestion is total recoverable as described in the ‘in bottle’ procedure (section 

10.2), then the preparation dilution factor is 1 not 1.25.

11.6 Units on the left side of equation are incorrect. The results as calculated will be in terms of 

micrograms per gram, NOT micrograms per kilogram.

12.1 How the MDL is calculated needs to be added. Eliminate section 12.2 and add to section 

12.1.

12.3 The procedure followed for calculating the IDL is not the one described in either methods 

200.8 or 1638, the two methods on which this SOP is based. Was this intended? If so an 

explanation of why this approach (i.e., average over three non-consecutive days multiplied 

by three) is required should be given.

12.4 This section has awkward and confusing wording. Revise and clarify this section. See also 

note A.7.

12.5 This section includes an ambiguous reference to analyst using ICVs from four distinct 

analytical sequences. Can they all be on the same day? What are the criteria?

16 The attachment list shows 1 through 8, but other attachments not included on this list are

referenced in the body of the draft SOP. 
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

Page 14

Sec. # Comment/Question

Attachment 2 The attachment should include additional internal standards (e.g., Ga, Rh, Bi, Ho, Tb) to 

provide backups for those internal standard elements that may be present in FGD 

wastewaters. It needs a statement that internal standards may be present “naturally” in 

some FGD wastewaters. For example, scandium will be present in some FGD matrices. 

Need a statement on when and how to substitute (see notes 4.3 and 10.4.3).

Attachment 3 Change footnote 2 to read that preservation should NOT be performed in the field. 

Preservation should be performed by the receiving laboratory under clean room conditions. 

Change footnote 4 to read within 15 minutes of sample collection as specified in the April 

2007 method update rule.

Attachment 4 Revise as per note 10.4.3.

In summary, I would like to emphasize three major points. First, it is essential that EPA validate

the data generated using the draft SOP with independent methods that were performed in the 

blind. We urge EPA to make this comparison before using the draft SOP for any additional 

sampling. Second, UWAG has significant concerns that commercial labs will not be able to 

implement the SOP as written. These comments contain detailed recommendations for 

improving the SOP, and we think it is well worth the time and effort to improve the SOP now, 

before it is used for any analyses related to the rulemaking. Third, the quality control approach 

spelled out in the SOP is not robust enough for FGD wastewaters. As we have been emphasizing 

for several years, FGD wastewaters present a significant analytical challenge that merits 

additional QC to ensure accurate results. 

Please call me if you would like to discuss these comments. 

Sincerely,

Donna B. Hill

Chair, Effluent Guidelines Committee

cc: Mr. Lemuel Walker 
Mr. Ronald P. Jordan

Mr. Richard W. Reding

March 19, 2010

Page 15

References Cited 

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Inductively Coupled Plasma-Mass Spectrometry rev. 5.4. Environmental Monitoring 

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U.S. EPA. 1996. Method 1638: Determination of trace elements in ambient waters by inductively 

coupled plasma-mass spectrometry. EPA 821-R-95-031. Office of Water. Washington, DC. 

47 pp.

U.S. EPA. 1996. Method 1669: Sampling ambient water for trace metals at EPA water quality 

criteria levels. EPA 821-R-96-005. Office of Water, Engineering and Analysis Division, 

Washington, DC .36 pp.

U.S. EPA. 2001. Guidance for Implementation and Use of EPA Method 1631 for the Determination 

of Low-Level Mercury (40 CFR part 136). EPA 821-R-01-023 (March 2001). Office of Water, 

Engineering and Analysis Division, Washington, DC. 48 pp.

U.S. EPA. 2002. Method 1631, revision E: Mercury in Water by Oxidation, Purge and Trap, and 

Cold Vapor Atomic Fluorescence Spectrometry. EPA-821-R-02-019. Office of Water, 

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U.S. EPA. 2007. Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the 

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Drinking Water Regulations; Analysis and Sampling Procedures; Final Rule. Federal Register 

(3-12-2007) 72(14) 11200-11249.

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