EFtt
United States
Environmental Protection
Agency
Protocol for the Evaluation of Alternate Test
Procedures for Analyzing Radioactive Contaminants
in Drinking Water
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Off ice of Water (MS-140)
EPA815-R-15-008
February 2015
Questions concerning this document should be addressed to:
Steyen_C.JA/ende|kenJ_PhD
U.S. EPA, Office of Ground Water and Drinking Water, Standards and Risk Management Division-
Technical Support Center, 26 W. Martin Luther King Dr. Cincinnati, OH 45268
Phone:(513)569-7491
wendelken.steve@epa.gov
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Foreword
Within EPA, the Office of Water publishes test methods (analytical methods) for the analysis of drinking
water. Listed at part 141 of Title 40 in the Code of Federal Regulations (CFR), these methods are
authorized for use in data gathering and environmental monitoring under the Safe Drinking Water Act.
These methods have been developed by EPA, by consensus standards organizations and by others to
satisfy the data quality mandates of the Safe Drinking Water Act.
This document gives specific information to external organizations regarding the submission, validation
and EPA evaluation of modifications or changes to an existing procedure or a new method for the
measurement of radioactive contaminants in drinking water, herein called alternate test procedures
(ATPs). EPA anticipates that the standardized procedures described herein should encourage the
development of innovative technologies, expedite the evaluation of ATPs and enhance the overall utility
of the EPA-approved methods for compliance monitoring under the National Primary Drinking Water
Regulations.
The Office of Ground Water and Drinking Water reviewed and approved this document for publication.
Neither the U.S. government nor any of its employees, contractors, or their employees make any
warranty, expressed or implied, or assumes any legal responsibility for any third party's use of, or the
results of such use, of any information, apparatus, product, or process discussed in this protocol. The
mention of company names, trade names, or commercial products does not constitute an endorsement
or recommendation for use.
This document does not alter, substitute for, establish or affect legal obligations under Federal
regulations. This document is not a rule, is not legally enforceable, and does not confer legal rights or
impose legal obligations on any federal or state agency or on any member of the public. Interested
parties are welcome to suggest procedures that are different from what's recommended in this
document. EPA reserves the right to change this protocol without prior notice.
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Foreword ii
Disclaimer ii
Acknowledgements Error! Bookmark not defined.
1 Introduction 1
1.1 Background and Objectives 1
1.2 Scope and Application 1
2 Overview of the ATP Process 1
2.1 Submission (initial application and subsequent documentation) 2
2.2 Application Information 2
2.2.1 Justification for ATP 2
2.3 Confidential Information in Applications 2
3 Method Development and Validation Study Plan 3
3.1 Validation Study Plan Elements 3
3.1.1 Background 4
3.1.2 Study Management 4
3.1.3 Technical Approach 4
3.1.4 Data Reporting and Evaluation 4
3.1.5 Limitations 4
3.2 Approval of Validation Study Plan 4
4 Method Validation Study 5
4.1 Introduction 5
4.2 Candidate Radiochemistry Test Method Validation Study Design 5
Table 1. Types and Numbers of Samples Required for the Candidate Test Method Validation Study 6
4.3 General Study 6
4.3.1 Selecting and Supporting the Participating Laboratories 6
4.3.2 Validation Study Test Matrix 6
4.3.3 Significant Figures, Rounding Data Results and Data Reporting Conventions 7
4.3.4 Uncertainty Evaluation and Reporting 7
4.4 Performing the Reagent Blank and Detection Limit Studies 8
Figure 1. Reagent Blank Study Process 8
4.4.1 Reagent Blank Study 9
4.4.2 Detection Limit Test and Detection Limit Study 9
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4.5 Method Performance Study 10
4.6 Acceptability Criteria for Radiochemical Study Results 11
4.6.1 Experimental Detection Limit Studies 11
4.6.2 Method Performance Study Criteria 11
Table 2. Means and Standard Deviations (from NELAC Performance Testing Criteria) 12
4.6.3 Bias Evaluation for the Method Performance Study 12
4.6.4 Precision Evaluation for the Method Performance Study 13
4.7 Acceptability Criteria for Quality Control Tests 14
4.8 Validation Studies Review 14
5 Final Application 14
5.1 Introduction 14
5.2 Final Application and Supporting Materials 15
5.2.1 Validation Study Report 15
6 Approval Recommendation 18
7 Quality Control 18
8 References 19
Appendix A: Application and Document Submission Form A-l
Appendix B: Standard EPA Method Format B-l
Appendix C: Procedure for Preparing the Radiochemistry ATP Drinking Water Test Matrix C-l
Table 3. Test Matrix Solution Composition Chart C-5
Appendix D: Calculating Theoretical Detection Limits for Radiochemical Measurements D-l
Appendix E: Sample Calculations E-l
Table 4. Example Detection Limit Study Results Spiked at 2.5 pCi/L E-l
Table 5. Example Method Performance Assessment Study Results Spiked at 200 pCi/L E-3
IV
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1 Introduction
1.1 Background and Objectives
Pursuant to the Safe Drinking Water Act, EPA promulgates test procedures (analytical methods) for data
gathering and compliance monitoring under National Primary Drinking Water Regulations.
Under the Agency's ATP program, an organization may request evaluation of a method as an alternate
test procedure to a method already approved in the drinking water regulations. These alternate
methods will be referred to as "candidate" test methods through the remainder of this document. The
organization or entity seeking the evaluation is responsible for validating the candidate test method.
EPA evaluates test methods used to measure regulated contaminants in drinking water for nationwide
approval. This requires EPA to assess any candidate test method in such a manner that its
interlaboratory range in accuracy, precision and detection capability can be compared to EPA-approved
test methods measuring the same target analyte(s). To be considered for approval, the candidate test
method must be equally as effective as the approved method (see Safe Drinking Water Act §1401(1));
that is, method's performance characteristics in general must be equivalent to, or better than, those of
existing approved methods for the contaminant of interest. This allows EPA to ensure that data
gathered under the Safe Drinking Water Act are comparable on a nationwide basis. For those methods
that demonstrate acceptable performance through their ATP evaluation, EPA will initiate an appropriate
approval action.
1.2 Scope and Application
The protocol design described in this document is consistent with candidate test method validation
requirements in other areas of chemistry, but has been modified to adjust for the technical differences
between chemical and radiochemical test methods. Radiochemical test methods differ from the other
areas of analytical chemistry in three ways: 1) the types of detection systems used are different, 2) the
chemical yields for sample preparation steps are generally measured and corrected for and 3) the DLs
for radiochemical test methods for finished drinking water analyses are specifically defined by Federal
regulation. This validation protocol is designed to address these differences with special attention to the
manner in which accuracy, precision and detection capability are assessed for method approval.
2 Overvie\ I Hi ^ 'I'M %cess
Agency staff reviews the application, including justification for the ATP provided by the applicant and
determines whether an ATP evaluation is warranted. If the application is accepted for ATP
consideration, the applicant then develops a validation study plan in consultation with ATP staff. Once
the study plan is approved, the applicant performs the validation study and submits a validation study
report to the ATP program. If EPA determines that the laboratory validation demonstrates performance
equivalent to or better than that obtained with an approved method, EPA will generally recommend
approval using one of two options: 1) approval through the conventional "notice and comment"
rulemaking process, or 2) approval through the expedited method approval process. Additional
information on the expedited method approval process can be found on
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2,1 Submission (iiniiti I HI, plication and subsequent documentation)
Applicants should submit ATP applications (see A£gendix_A) to the Drinking Water ATP Coordinator.
Upon receipt of the application, the ATP staff will assign an identification number to the application. The
applicant should use the identification number and Appendix A as a cover sheet for all future
communications and any supplemental documentation concerning the application.
2,2 Application Information
Information required on the ATP application includes: the name and address of the applicant; the date
of submission of the application; the title of the proposed candidate method; the analyte(s) for which
the ATP is proposed; a brief summary of the proposed method and the justification for proposing the
ATP. The applicant should provide all required application information and any associated attachments
in order for the application to be considered complete.
2.2.1 Justification for ATP
The applicant should provide a brief justification for why the ATP is being proposed. Because EPA review
and evaluation of proposed ATPs can entail considerable effort, EPA strives to minimize the submission
of impractical methods or method modifications that fall within the scope of flexible options already
allowed in an approved method or in EPA's "Technical Notes on Drinking Water Methods" (EPA
Document No. EPA-600-R-94-173, October 1994). Examples of appropriate justifications include but are
not limited to: the candidate method successfully overcomes some or all of the interferences associated
with the approved method; the candidate method reduces the amount of hazardous wastes generated
by the laboratory; the cost of analyses or the time required for analysis is reduced; or, the quality of the
data is improved. It is highly recommended that the method developer consult with ATP staff
concerning the proposed candidate method and its justification prior to extensive method development.
2.3 Confidential Information in Applications
When you submit information with the proposed ATP application, you may, if you desire, assert a
business confidentiality claim covering part or all of the information. The method for submitting a claim
is described in the regulations at 40 CFR 2.203(b). EPA staff will handle such information according to
the regulations in subparts A and B of 40 CFR Part 2. Information covered by such a claim will be
disclosed by EPA only to the extent, and by means of the procedures, set forth in 40 CFR Part 2, Subpart
B. If no such claim accompanies the information when it is received by EPA, it may be made available to
the public by EPA without further notice to the business.
Specifically, in accordance with 40 CFR §2.203(b), a business may assert a business confidentiality claim
covering the information by placing on (or attaching to) the information at the time it is submitted to
EPA, a cover sheet, stamped or typed legend, or other suitable form of notice employing language such
as trade secret, proprietary, or company confidential. Confidential portions of otherwise non-
confidential documents should be clearly identified and may be submitted separately to facilitate
identification and handling by EPA. If confidential treatment is only required until a certain date, the
notice should state so accordingly. It should be noted, however, that any methods to be proposed for
approval in the Federal Register cannot themselves be claimed as confidential business information.
If a claim of business confidentiality is received after the information itself is received, EPA will make
such efforts as are administratively practicable to associate the late claim with copies of the previously
submitted information in EPA files. However, EPA cannot ensure that such efforts will be effective in
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light of the possibility of prior disclosure or widespread prior dissemination of the information, See
§2.203(c).
3 Method Development and Validation Study Plan
Method development and validation is the process by which a laboratory substantiates the performance
of a method by demonstrating that the method can meet EPA's acceptance criteria and that the method
is rugged, that is, yields acceptable method performance and data quality over the range of drinking
water sample types and over the range of laboratory conditions specified in the method. In order to
produce a method that is rugged and meets quality control acceptance criteria, the method developer
needs to have a firm understanding of the chemistry involved in the method. Because methods vary
widely in their chemistry and procedures, no definitive global guidance can be provided on how to
develop a rugged method. In general, though, all candidate methods should: (a) identify critical points of
each step in the procedure, (b) demonstrate that these critical points are satisfactorily addressed or
controlled in the method and (c) demonstrate that acceptable method performance is attained using all
procedural options specified in the method.
Critical points of a method can take a variety of forms depending on the method. For example, certain
methods may require extraction of an analyte at a specific pH or narrow pH range. Thus, for the method
to be truly rugged, pH control (for example, use of buffers) may be required to ensure that other
samples, laboratory conditions, or chemists obtain satisfactory results using the method. For candidate
methods intended to be used in the field, ambient temperature may be a critical factor affecting
performance of the method. The applicant should examine and control such factors, or limit the
conditions under which the method can be used. Other examples of critical steps requiring ruggedness
demonstration are:
Determination of the breakthrough volume in solid phase extraction.
Effect of laboratory temperature on a purge and trap method.
Determination of a critical solvent to sample ratio in liquid-liquid extraction.
Many methods have procedural options in certain steps, for example, a choice of two sample
preservation agents. If more than one preservation option is specified in a candidate method, the
applicant must demonstrate acceptable method performance using both preservation options. Similarly,
if a candidate method specifies either of two different solid phase sorbents for extraction, the applicant
must demonstrate acceptable performance using both sorbents.
Once an application has been accepted by the ATP program, the applicant should discuss their plans to
address method ruggedness with ATP staff prior to formulating the validation study plan. Such
consultation will help avoid both inadequate study plans (for example, not enough analyses addressing
critical points of the method) and study plans with unnecessary analyses. The following sections
summarize the major components of the validation study plan.
3.1 Validation Study Plan Elements
Prior to conducting the candidate method validation study, the applicant should prepare and submit a
detailed study plan for EPA approval. The technical details for the validation study design are found in
Section_4.0. The validation study plan should contain the elements described in Sections 3J.JL through
3.1.5 of this document.
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3.1.1 Background
The Background section of the validation study plan should:
Identify the candidate test method.
Include a summary of the candidate test method.
Describe the reasons for development, the logic behind the technical approach and the
advantages of the method in comparison to existing technology or methodology.
List the analytes measured by the candidate test method including corresponding Chemical
Abstract Services Registry Number (if applicable).
3.1.2 Study Management
The Study Management section of the validation study plan should:
Identify the organization responsible for managing the study.
Identify laboratories, facilities and other organizations that will participate in the study.
Delineate the study schedule following approval of the study plan.
3.1.3 Technical Approach
The Technical Approach section of the validation study plan should:
Describe how participating laboratories will be selected.
Explain who will prepare the test matrix and how it will be distributed.
Specify the numbers and types of analyses to be performed by the participating laboratories in
accordance with this protocol.
Identify specific reagents, materials, instrumentation or software required.
3.1.4 Data Reporting and Evaluation
The Data Reporting and Evaluation section of the validation study plan should explain the procedures
that will be followed for reporting and validating study data and should address statistical analysis of
study results.
3.1.5 Limitations
The Limitations section of the validation study plan should explain any limiting factors related to the
scope of the study.
3.2 Approval of Validation Study Plan
Once EPA is satisfied that the written method and the proposed study plan meet the criteria described
in this document, the applicant will be instructed to proceed with the method validation study.
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4.1 Introduction
Method validation is the process by which a method developer substantiates the performance of a
candidate test method. Candidate test methods should be validated to demonstrate they have
acceptable performance characteristics such as accuracy, precision and detection capability for the
measurement of their target radioanalyte(s). Although this is generally achieved by comparing the
performance of the candidate method to that of existing approved methods, additional metrics such as
robustness or ruggedness may also be evaluated.
Recently, the NELAC Institute published radiochemistry Performance Testing study acceptability criteria
that are based on the results of past radiochemistry Performance Testing studies (Rrfererice_2J|]_Sectiori
8). These acceptability limits are not test method-specific, but instead reflect the average performance
of all test methods for a specific radioanalyte. EPA may base the acceptability criteria for candidate test
methods validated using the procedures detailed in this protocol on the current NELAC Performance
Testing acceptability criteria. This approach will provide limits for performance characteristics that are
representative of the current proficiency for all the test methods currently in use.
4.2 Candidate Radiochemistry Test Method Validation Study Design
The candidate test method validation study design described in this protocol is intended to provide
sufficient data to determine the performance characteristics of candidate test methods and provide
data to determine whether constituents typically found in finished drinking water matrices will
adversely affect method performance. The study design will evaluate the candidate test method's
performance in obtaining measurements for the test matrix and determine if the candidate test method
is comparable to test methods already approved by EPA to measure the same target radioanalytes in
drinking water. The validation study is broken down into the Reagent Blank (RB) study, the Detection
Limit (DL) study (see Aj3]3endix_D for definition and discussion of the Safe Drinking Water Act DL) and the
method performance study.
Because the RB and DL studies assess the candidate test method's performance independent of matrix
effects, these studies should employ water equivalent to or better in quality than ASTM Type II water.
The method performance study will gather data to assess the candidate test method's performance in
the test matrix, which is representative of the types of samples that the method may be used to
measure on a routine basis. The method performance study's design is intended to provide sufficient
data to characterize the candidate test method's intra-laboratory and inter-laboratory performance.
Each study (RB, DL and method performance) is discussed in more detail in Section_4.4.
Under the validation study, the sample test matrix (as identified) should be analyzed at four different
matrix and spike level combinations by three certified laboratories and their results employed in the
validation study report. The applicant may elect to employ more than three laboratories or more than
four matrix and spike level combinations. However, in such cases, the applicant is responsible for
adjusting the calculations for the study appropriately. The number of study samples and the total
number of samples in a three lab study are listed below in Table 1.
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Table 1. Types and Numbers of Samples Required for the Candidate Test Method Validation
Study
Study
Reagent Blank
Detection Limit3
Method performance
Method performance
Method performance
Method performance
Sample Type
RB
DL (replicates spiked at
or below the target
radioanalyte's required
DL)
Reagent Water
Fortified at Maximum
Contaminant Level
Test Matrix at
Maximum Contaminant
Level
Test Matrix at Y-i
Maximum Contaminant
Level
Test Matrix at 2 x
Maximum Contaminant
Level
Number of Samples
per Participating
Laboratory1
6
7
7
7
7
7
Total Number of
Samples in a Three Lab
Study2
18
21
21
21
21
21
4.3 General Study
4.3.1 Selecting and Supporting the Participating Laboratories
A minimum of three laboratories should participate, in order to characterize inter-laboratory method
performance. The laboratories employed should be certified by EPA to test for radioanalytes in drinking
water. If the applicant is a certified laboratory, the applicant should locate at least two other certified
radiochemistry laboratories to participate in the method validation study with them. If the applicant is
not a certified laboratory, the applicant should obtain the services of at least three certified
radiochemistry labs. The applicant should provide the participating laboratories with the candidate test
method standard operating procedure, any technical assistance requested by them and with sufficient
volume of the test matrix to run the method performance study. The applicant should collect the
necessary data from the participating laboratories to produce a single validation study report and data
package for submission to EPA.
4.3.2 Validation Study Test Matrix
Finished drinking water matrices could potentially have levels of regulated and unregulated chemical
and radioactive constituents (that is, organics, solvents, cations, anions, metals, etc.) at concentration
levels by themselves or in summation with others that may interfere with the sample preparative steps
in a radiochemical test procedure. Since test methods used to monitor the compliance status of public
1 The total number of samples required per participating laboratory is 41.
2 The grand total number of samples required in a three lab study is 123.
3 In some cases the DL study may not be needed if the DL test is passed (see Secticmjyi for details).
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water systems are approved for nationwide use, any method validation study for candidate test
methods for drinking water should be conducted using a test matrix that is representative of the
diversity in both unregulated and regulated constituents that may be found in finished drinking water.
A single test matrix has been developed for use in the method performance study. This test matrix was
tested by EPA, is within the bounds of the types of finished drinking water that are found nationally and
is reasonable to test the method performance of a high ionic strength water matrix. The matrix sample
components and directions for preparing the test matrix are identified in Aggendjx^C.
The applicant should provide EPA with documentation that the test matrix was preserved and stored
according to the approved procedures for the candidate test method and that all analyses took place
within the required holding times. The applicant laboratory should ensure sufficient quantities of the
test matrix are available for all the test batches needed by all the participating laboratories.
4.3.3 Significant Figures, Rounding Data Results and Data Reporting Conventions
The value of a measurement result should: (1) be reported directly as obtained with appropriate units,
(2) all values should be reported even if they are negative, (3) be expressed in an appropriate number of
significant figures and (4) include an unambiguous statement of the uncertainty. The appropriate
number of significant figures is determined by the magnitude of uncertainty in the reported value.
The value, as measured (including zero and negative numbers) and the measurement uncertainty (either
expanded uncertainty or the combined standard uncertainty) should be reported in the same units. For
presentation of data in the method validation report the measurement uncertainty should be rounded
to two significant figures and both the value and uncertainty should be reported to the same number of
decimal places. For example, a value of 0.8961 pCi/L with an associated combined standard
measurement uncertainty of 0.0234 should be reported as 0.896 ± 0.023 pCi/L with a coverage factor of
one. Note: rounding should only be used in determining the final results.
4.3.4 Uncertainty Evaluation and Reporting
The submitted method should describe the equations or procedures used to evaluate the uncertainty of
each result. When describing uncertainties, the method should use the terminology and symbols of the
Guide to the Expression of Uncertainty in Measurement; International Standards Organization 1995
(ReferenceJJjiSect|on_8). Each measurement result should be reported with its associated counting
uncertainty in accordance with the applicable regulations; however, EPA also encourages labs to
perform a complete uncertainty evaluation and report the overall measurement uncertainty of each
result as well.
Since laboratories may calculate uncertainties using different methods and report them using different
coverage factors, uncertainties should be reported with an explanation of what they represent. In
particular, reports should clearly distinguish between counting uncertainties and total uncertainties.
Furthermore, any analytical report, even one consisting of only a table of results, should state whether
the uncertainty is a standard uncertainty ("one sigma") or an expanded uncertainty ("k sigma") and in
the latter case it should also state the coverage factor (k) and, if possible, the approximate coverage
probability. If the laboratory uses a shorthand format for the uncertainty, the report should include an
explanation of the format.
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Additional information about the evaluation and expression of uncertainty can be found in National
Institute of Standards and Technology Technical Note 1297: Guidelines for Evaluating and Expressing the
Uncertainty of National Institute of Standards and Technology Measurement Results (Eeference__3Jn
and the Multi-Agency Radiological Laboratory Analytical Protocols Manual (Reference_5_m
Section_8).
4.4 Perform in i the Reagent I I HI ill n I Detection Limit Studies
Participant laboratories should initially produce RB and DL data quantifying their performance with the
candidate test method that is independent of matrix interferences. These data assess laboratory
baseline proficiency with the candidate test method prior to assessing matrix interferences with a
candidate test method performance study.
The data generated by these initial demonstrations of performance are designed to determine if the
laboratory can perform the candidate test method and generate results comparable to those generated
using the approved test methods for a specific regulated radioactive contaminant or contaminants. The
candidate test method's detection capability is assessed with a RB study and DL study.
In some cases, applicants may only need to do the RB study and forgo the DL study if the candidate test
method can successfully pass the DL test in Section 4A2.L
Figure 1. Reagent Blank Study Process
Perform Reagent Blank
Study
(Section 4.4.1)
Perform Detection Limit
Test
(Section 4.4.2.1)
Investigate
further*
Continue to
Method
Performance
Study
Perform Detection Limit
Study
(Section 4.4.2.2)
Continue to
Method
Performance
Study
Investigate
further*
* If the RB or DL study fail, the applicant may wish to modify the method
and repeat the calculation. If a method modification is necessary, the
applicant should notify KPA of the modification before proceeding.
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4.4.1 Reagent Blank Study
Each participating laboratory should demonstrate that it is capable of measuring the analyte at
sufficiently low levels to determine if the candidate test method can meet the required DL for the target
radioanalyte(s). An RB analysis is performed to measure the effect of possible contamination of the
reagents and lab ware. The RB study should use deionized water that meets or exceeds the ASTM Type II
standard for reagent water. This sample should be free of matrix interferences and will allow an initial
assessment to be made for the candidate test method's baseline performance as it is used by the
participating laboratories. Each participating laboratory should use the candidate test method to
prepare and measure two RBs on three non-consecutive days for a total of six RBs. The RBs should be
assumed to be a normal sample that is dispensed, prepared and processed with the reagents and
procedures specified in the candidate test method for routine sample analysis. They should be
measured using the detection system specified in the candidate test method using the count times
calculated as necessary for routine sample measurements in order to meet the required DLs. The
average net activity for these RB measurements should then be calculated. For each participating
laboratory, the absolute value of the average net activity found in the study's RBs should not exceed
one-half of the required DL for each radioactive contaminant measured using the candidate test method
as they are listed in Table B at 40 CFR part 141.25(c)(l) and Table C at 40 CFR part 141.25(c)(2). If the
absolute value of the average net activity found in the study's RBs exceeds one-half of the required DL,
the applicant may wish to modify the method and have each participating laboratory repeat the RB
study. If a method modification is necessary, the applicant should notify EPA of the modification before
proceeding.
4.4.2 Detection Limit Test and Detection Limit Study
The candidate test method should be evaluated against the DL test criteria to determine if an additional
DL study should be done. If the candidate test method can pass the DL test, applicants can forgo the DL
study and begin the method performance study.
4.4.2.1 Detection Limit Test.
If the method always produces a result (positive, negative or zero) and if there are theoretically
defensible equations for calculating the DL, then the applicant may determine the DL by a documented
calculation without performing a DL study. For more information on calculating theoretical DLs for
radiochemical measurements see Aj3geridix_D. In this case, the calculated DL must not exceed the
required DL. As an additional check, the results of the RB analyses will be evaluated statistically to test
whether the observed variability significantly exceeds the standard deviation expected at the required
DL, as shown below.
4,4,2,1,1 Statistical Evaluation of the Reagent Blanks
Let Bi, 62, ..., Bn denote the results of all the RB analyses (for example, n = 18 if there are three labs and
six blanks per lab). Calculate the following statistic I/I/:
(1)
RDL2 '
The critical value for I/I/ is the 99th percentile of the chi-squared distribution with n degrees of freedom.
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Wc = .
(2)
For example, if n = 18, the critical value is Wc = 34.81.
The candidate test method should NOT be deemed to pass the DL test if W > Wc and the applicant
should conduct a DL study. If EPA determines that the data appear suspect (for example, if all the blank
results are exactly zero) the applicant may be requested to perform a DL study.
4.4,2,2 Detection Limit Study.
The DL study will verify that the method is capable of routinely achieving the required detection
capability for the method. Whenever practical, the first step of the DL study should be a theoretical
estimation of the Safe Drinking Water Act DL based on the definition in 40 CFR 141.25(c) and all relevant
data obtained in the method background study, such as instrument background levels, chemical yields,
etc. °f this document describes how to calculate such a theoretical estimate in the simplest
cases. If the theoretical estimate of the DL does not exceed the required DL, an experimental DL study
should be performed as described below. However, if the theoretical estimate of the DL exceeds the
required DL, the performance of the method will be considered inadequate and there will be little value
in completing the experimental DL study. In this case, the applicant may wish to modify the method (for
example, increase counting time or increasing the sample volume) and repeat the calculation of the
theoretical estimate of the DL. If a method modification is necessary, the applicant should notify EPA of
the modification before proceeding. If a theoretical estimation of the DL is found to be impractical, the
experimental DL study is required.
The experimental DL study consists of seven replicate samples. Each sample should be made with ASTM
II reagent water, at a minimum, using the sample volume prescribed in the method. The sample should
be spiked with National Institute of Standards and Technology traceable source(s) of the method target
radionuclide(s) to an activity concentration at or below their required DL. The sample should be mixed
and then processed through sample preparation, processing and analysis per the candidate test method.
The measurements of the DL study samples will then be assessed by calculating a precision statistic. See
Section 4.6.1 for further information.
4.5 Method Performance Study
The method performance assessment study is to be performed by three laboratories, each analyzing
seven replicates at four different matrix and spike level combinations, as listed below:
1) Reagent water, spiked at the Maximum Contaminant Level.
2) The test matrix, spiked at the Maximum Contaminant Level.
3) The test matrix, spiked at Yi the Maximum Contaminant Level.
4) The test matrix, spiked at 2 times the Maximum Contaminant Level.
The results of the bias and precision evaluations are subject to the criteria as described in Sections 4J63,
and 4.6.4, respectively, at each matrix and spike level for the study to be acceptable. Therefore, it is
recommended that the analyses be performed in reagent water first, then in the order of increasing
concentration in the matrix. There is no need to complete all four sets of analyses if one has failed.
If either the results of the bias or precision evaluations fails the criteria for any spike level or matrix,
then the applicant should investigate why the method failed the criteria and possibly modify the method
10
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and repeat the calculation. If a method modification is necessary, the applicant should notify EPA of the
modification before proceeding.
4.6 Acceptability Criteria for Radiochemical Study Results
The NELAC Institute has published and maintained a table of radiochemical Performance Testing study
acceptability criteria (Refej£nce_2JnJ>ection_8). The calculations discussed in this section were
developed to account for the presence of variability between multiple laboratories. The precision
evaluation in Section 4.6.4 is based on the single-laboratory standard deviations (presented in Jable_2)
that were used to develop the NELAC performance testing criteria. Assessing method performance using
these criteria will help ensure compliance monitoring measurements for regulated contaminants that
meet or exceed a minimum acceptable level of performance for laboratories nationally.
4.6.1 Experimental Detection Limit Studies
The assessment of the replicate results for one analyte at all of the participating laboratories uses a chi-
square statistic to test whether the pooled relative standard deviation of the results exceeds the
maximum value allowed at the required DL
Calculate the mean, Xt and a chi-square statistic, % for each of the participating laboratories,
2 1 962
and =-X,-Xt (3)
Where:
m is the number of laboratories (three or more).
n is the number of replicate measurements (n = 7).
\JL is the spike concentration (not to exceed the required DL).
X/yisthe result of they* replicate measurement (/= 1, 2, ..., n) at the ith laboratory (/= 1,2,..., m).
Then calculate the overall chi-square statistic:
2 _ V"1 2
~ / j/Cj (4)
/=!
To be deemed acceptable, the value of % should be less than or equal to the 99 percentile of the
distribution with m x (n-1) degrees of freedom. When n = 7 and m = 3, the value of this percentile is
34.81.
Note: Refer to ApjDendix_E - Sample Calculations Section 1.0 for an example calculation.
4.6.2 Method Performance Study Criteria
Sections 4J33 and 4.6.4 present the step-by-step processes by which the bias and precision of the
method performance study data should be assessed. In the event that the NELAC Institute updates their
11
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performance testing acceptability criteria in the future, the updated table should be used to reference
these limits until an addendum to or revision of this document is published.
Table 2. Means and Standard Deviations (from NELAC Performance Testing Criteria)
Analyte
Gross Alpha
Gross Beta
Barium-133
Cesium-134
Cesium-137
Cobalt-60
lodine-131
Radium-226
Radium-228
Strontium-89
Strontium-90
Tritium
Natural Uranium
Uranium (mass)
Zinc-65
Spike Level Range (u,1)
7 to 75
8 to 75
10 to 100
10 to 100
20 to 240
10 to 120
3 to 30
Ito20
2 to 20
10 to 70
3 to 45
1000 to 24000
2 to 70
3 to 104 u.g/L
30 to 360
Standard Deviation (oNELAC)
(0.1610 u,) + 1.1366
(0.0571 u.) + 2.9372
(0.0503 u.) + 1.0737
(0.0482 u.) + 0.9306
(0.0347 u.) + 1.5185
(0.0335 u.) + 1.3315
(0.0624 u.) + 0.6455
(0.0942 u.) + 0.0988
(0. 1105 u.) + 0.3788
(0.0379 u.) + 2.6203
(0.0902 u.) + 0.5390
(0.0532 u.) + 38.8382
(0.0700 u.) + 0.2490
(0.0700 u.) + 0.3700
(0.0530 u.) + 1.8271
Based on an EPA study using the test matrix, the following spike levels should be used for Barium-133
and Cesium-134:
Barium-133 - 50 pCi/L equivalent to slightly greater than 1/2 the Maximum Contaminant Level
of Barium-140 (90 pCi/L).
Cesium-134 - 40 pCi/L equivalent to 1/2 the actual determined Maximum Contaminant Level.
4.6.3 Bias Evaluation for the Method Performance Study
In order to assess whether the average concentration of the replicates for a given spike level and matrix
is significantly different from the spike level, it is first necessary to calculate r, the ratio of the between-
laboratory standard deviation to the within-laboratory standard deviation.
1) The within-laboratory standard deviation (sw) and the between-laboratory standard deviation
calculated as follows:
are
(5)
Where:
sf is the standard deviation of the 7 replicate results for laboratory /.
u. = spike level (pCi/L or u.g/L)
12
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Where:
Xt is the mean of the 7 results for laboratory /.
X is the grand mean of the 21 results over all three laboratories.
Note: If the radicand is negative, Sb should be set to zero.
2) Calculate the ratio r:
(7)
3) Using oNELAC (Tab|e_2), calculate the acceptable combined standard deviation for the lab averages,
oc,:
Note: The appropriate value of oNELAC may differ for different spike levels.
4) For the method to be acceptable, the grand mean, X , should be within the following range:
a X2.58
Where:
u. is the spike level.
2.58 is the 99.5th percentile of a standard normal deviation distribution.
Refer to Appendix E - Sample Calculations Section_2.1 for an example calculation.
4.6.4 Precision Evaluation for the Method Performance Study
Calculate a statistic for total precision using the equation below.
°"NELAC *'=
do)
13
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Where:
^"NELAC 's determined from J_abje_2.
X is the grand mean of the 21 tests over three laboratories for the given spike level and matrix.
For the method to be acceptable % should be below the 99th percentile of the chi-square distribution
with 20 degrees of freedom (37.57). Refer to Appendix E - Sample Calculations Sectioji_Z,2 for an
example calculation.
4.7 Acceptability Criteria for Quality Control Tests
Candidate test method Standard Operating Procedures should reference Chapter VI, Critical Elements
for Radiochemistry, in The Manual for the Certification of Laboratories Analyzing Drinking Water (EPA
815-R-05-004) for the required instrument stability checks and preparation batch quality control
samples, their frequencies and acceptability limits (Reference_6Jn_Section_8).
4.8 Validation Studies Review
After completing the validation studies of candidate test methods, the organization responsible for
developing the method should document the study results and submit them to EPA. EPA will review the
results and contact the responsible organization to answer any question or concerns raised based upon
the provided results. If necessary, EPA may require further testing or clarification prior to the originator
proceeding with final application.
1 i 1 1 1 1 1 i ...... i 1 1
After completion of the validation study, the applicant should submit a final application. The final
application will be combined with the initial application materials to constitute the complete
application. If the results of the validation study indicate that the candidate test method should be
approved, EPA will generally pursue approval using one of two options: 1) approval via the conventional
"notice and comment" rulemaking process or 2) approval via the expedited method approval process.
Information about this process can be found on £PA^^E§dited_rriethod_web_gage. If based on its
review of the method, EPA concludes that the method is not sufficiently rugged or reliable for its
intended use, EPA may require further method development and further testing to define the stability
and reliability of the method. The tests and studies that should be performed in this case are dependent
upon the analyte(s) and the analytical system and will be determined on a case-by-case basis as these
situations arise.
Section 5.2 describes the materials and information needed for the final application. Applications should
be made in triplicate and should include a completed application form (provided in AjD|Deridix_A of this
document) with required attachments. All applications for EPA evaluation of radiochemistry candidate
test methods to be used for Safe Drinking Water Act compliance monitoring should be sent along with
all application materials to the following address:
S_teyen_C._Wende[kenJ_Ph^
U.S. EPA, Office of Ground Water and Drinking Water-Technical Support Center
26 W. Martin Luther King Dr.
14
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MS-140
Cincinnati, Ohio 45268
Phone:(513)569-7491
Fax:(513)569-7837
wendelken.steve@epa.gov
5.2 Final Application and Supporting Materials
The final application should include:
Completed final application form - an application form filled out as described in Section 2.2.1
(but identified as a final application).
Data Certification Form.
Method validation study report including the raw study data.
Method development information and documentation.
5.2.1 Validation Study Report
Laboratories or other organizations responsible for developing new candidate radiochemical test
methods for drinking water monitoring should document the results of the validation study in a formal
validation study report that is organized and contains the elements described in this section. In all cases,
a copy of all required validation data should be maintained at the laboratory or other organization
responsible for developing the candidate test method.
The information and supporting data required in the validation study report should be sufficient to
enable EPA to evaluate the performance of a candidate test method. The applicant is responsible for
ensuring that all method-specified requirements are met by the participating laboratories and that the
validation study report contains all necessary data.
The validation study report should:
Contain background information and describe the study design.
Detail the process and results of the study.
Provide an analysis and discussion of the results and present study conclusions.
Identify and discuss any deviations from the study plan that were made.
Contain the elements described in sections 5.2.1.1 through 5.2.1.9.
Reference the validation study plan and include the plan as an appendix.
5.2.1,1 Background
The Background section of the validation study report should:
Include a method summary that describes the candidate test method that was validated.
Identify the organization responsible for developing the method.
Describe the reasons for developing the candidate test method, the logic behind the technical
approach to the candidate test method and the result of the candidate test method.
List the analytes measured by the method including corresponding Chemical Abstract Services
Registry Number (if applicable).
State the purpose of the study.
Cite any studies of the method or papers whose studies use data collected using the candidate
test method that have been published in peer reviewed literature.
15
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5,2,1,2 Study Implementation
The Study Implementation section of the validation study report should:
Describe the methodology and approach undertaken in the study.
Identify the person or organization that was responsible for managing the study.
Identify the laboratories, facilities and other organizations that participated in the study.
Describe how participating laboratories were selected and explain the role of each organization
involved in the study.
Include initial performance data from each of the participating laboratories using the candidate
test method.
Delineate the study schedule that was followed.
Describe how the test matrix was prepared and how samples were distributed
Specify the numbers and types of analyses performed by the participating laboratories.
Identify any problems encountered or deviations from the study plan and their resolution or
impact on study performance or results or both.
5,2,1,3 Data Reporting and Validation
This section of the validation study report should describe the procedures that were used to report and
validate study data. EPA has not established a standard format for analytical data submission because of
the large variety of formats currently in use.
5.2,1,4 Results
This section of the validation study report should present the study results in summary form. Raw data
and example calculations are required to support the results and should be included in Appendix C to
the validation study report (see Section_5.2.1.9).
5,2,1,5 Data Analysis and Discussion
This section of the validation study report should:
Provide a statistical analysis and discussion of the study results.
Present and discuss the candidate test method's observed accuracy, precision and detection
capability.
5,2,1,6 Co n clus io ns
This section of the validation study report should:
Describe the conclusions drawn from the study based on the data analysis discussion.
Contain a statement(s) regarding achievement of the study objective(s).
5,2,1,7 Appendix A - The Method
Include a copy of the candidate test method standard operating procedure as Appendix A to verify no
changes in the procedure occurred since its submission with the initial application. If any changes to the
method occurred after its submission in the initial application (such as the result of unforeseen factors
discovered during the method validation study) a track edits copy (in Microsoft© Word or Excel format)
along with a description of the changes and an explanation why they were necessary should be
included. The updated standard operating procedure should also adhere to the standard EPA format or
if the method is sponsored by another government agency or consensus standards organization, their
preapproved required format.
16
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5.2.1,8 Appendix B - Validation Study Plan
Attach a copy of the EPA approved validation study plan as Appendix B.
5.2,1.9 Appendix C - Supporting Data
The validation study report should be accompanied by raw data and example calculations that support
the results presented in the report. These data and calculations should be included in the report as
Appendix C.
5.2.1.9.1 Raw Data
This section of the validation study report should include raw data as generated (that is, without
rounding) that will allow an independent reviewer to verify each determination and calculation
performed by the laboratory. EPA will perform a detailed audit of the candidate test method validation
study data. The evaluation of data submitted in support of applications can be accomplished more
quickly if machine-readable files of test data (spreadsheets) are provided. This data verification consists
of tracing the instrument output (for example, instrument background counting rates, gross sample
counting rates, for spectrometric methods the peak height or area or other indicators of signal intensity)
to the final result reported. The raw data are method specific and may include any of the following:
Sample measurement operating conditions, including detailed information on:
o Type of detector used.
o Sample count times.
o Volume of samples.
Spectrum printouts should be submitted for each sample (if the candidate test method collects
spectra) with any library search result used to quantitate data from the spectrum.
Control charts and data from the instrument used to establish its stability with regard to
calibration including background during the time period of the analyses.
Identification of any analyte-specific efficiency standards used or prepared for the ATP.
Sample numbers or other identifiers used by the both the regulated entity and the laboratory.
Sample preparation (precipitation and column separations) dates.
Analysis dates and times.
Sequence of analyses or run logs.
Quantitation reports, direct instrument readouts or data system outputs, or both, sufficient to
allow a third party to regenerate or reconstruct the calculations.
Laboratory bench sheets and copies of all pertinent logbook pages for all sample preparation,
cleanup steps and for all other parts of the determination.
Raw data should be provided for all samples, calibrations, verifications, blanks, matrix, spikes, duplicates
and other quality control analyses required by the candidate test method. Data should be organized so
that an analytical chemist can clearly understand how the analyses were performed. The names and
titles of the analysts who performed the analyses and of the quality assurance officer who verified the
analyses should be provided.
5.2.1.9,2 Exa m p I e Ca I c u I a t i o in s
The validation study report should provide example calculations that will allow the data reviewer to
determine how the laboratory used the raw data to arrive at the final results. All formulas for sample
activity concentration, uncertainty of the measurement and the DL calculation used to set the count
times and volumes should be included in the Example Calculations section. Examples of other method
specific calculations, such as those for assessing method detection efficiency or chemical recovery of a
17
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carrier or tracer, should also be included. All constants and variables used in the calculations should be
specifically defined. An example calculation should have the general formula on the first line, sample
specific data then included in the formula on the second line, then an appropriate number of lines
demonstrating the mathematical simplification and derivation of the final result.
6 Apprc «! ' v1 "!> i> iii ' .11> h
EPA will complete its review and notify the applicant of EPA's recommendation. If the candidate test
method is recommended for approval, EPA will generally pursue approval using one of two options: 1)
approval via the conventional "notice and comment" rulemaking process or 2) approval via the
expedited method approval process. Find additional information on ^PA^s_exgedjted_method_web_gage.
7 'i .1, i i
Laboratories measuring radiochemical compliance monitoring samples in support of the Safe Drinking
Water Act should follow the requirements found in Chapter VI, Critical Elements for Radiochemistry, in
(EPA815-R-05-004). Section
7.4 in Chapter VI of this manual requires laboratories to participate in at least one Performance Testing
study per year for each regulated radioactive contaminant using a specific method for certification.
Section 7.7 in the same chapter specifies quality control tests and their acceptance criteria to assess
sample preparation batch accuracy, precision, detection capability and interferences. Section 7.7 also
requires instrument quality control checks be made in order to monitor their stability. Instrument
specific calibration requirements and stability checks are described in Section 3.1. Section 7.8 in Chapter
VI states that laboratories should collect quality control data and order them by quality control test in a
control chart in order to document each method's performance and the stability of counting
instrumentation. In order to ensure data consistency and reliability nationally, the requirements found
in Chapter VI should be followed along with any quality control requirements found in currently
approved methods.
The contents of the quality control section (9) in candidate method standard operating procedures
should be consistent with the requirements found in Chapter VI. The candidate test method standard
operating procedure should specify either the sample preparation batch quality control tests, the
instrument stability checks and their acceptance criteria as they are found in Chapter VI or explicitly
reference where the quality control test requirements appropriate to the candidate method may be
found in Chapter VI.
18
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:es
1. International Organization for Standardization. (1995). Guide to the Expression of Uncertainty in
Measurement. Geneva, Switzerland.
2. The NELAC Institute, (n.d.). fMsiMchemisti^J^e^ Retrieved from
The NELAC Institute: http://www.nelac-institute.org/
3. U.S. Department of Commerce. (1994). Gorcfc^ne^jfe^^
Retrieved from National Institute of Standards and Technology: http://www.nist.gov/
4. U.S. Environmental Protection Agency. (1996). Guidelines and Format for Methods to Be
Proposed at 40 CFR Part 136 or Part 141 (Guidelines and Format document). EPA 821-B-96-003.
Washington, D.C.
5. U.S. Environmental Protection Agency. (2004). Multi-Agency Radiological Laboratory Analytical
Protocols Manual. NUREG - 1576, EPA402-B-04-001C.
6. U.S. Environmental Protection Agency. (2005). Chapter VI, Critical Elements for Radiochemistry.
The Manual for the Certification of Laboratories Analyzing Drinking Water. Washington, D.C.:
EPA 815-R-05-004.
19
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Appendix
I '!
EPA Office of Ground Water and Drinking Water
Alternate Test Procedure Candidate Method Application
D Initial Application
D Supplemental Documentation
D Final Application
Applicant Information
Applicant Name:
Address:
State:
Zip Code:
Contact name:
Phone number:
Email address:
Submission Date:
Candidate method:
Analyte(s):
Candidate test method title:
Reference method number or name or both:
Attachments
D Justification for Candidate Test Method
D Validation Study Plan
D Validation Study Report
D Raw Data Package (spreadsheets, calibrations, etc.)
D Data Collection Certification
D Other Documentation:
EPA use only
Case number:
A-l
-------
Data Coll lection Certification
It is the expectation of the ATP program that all data will be collected as outlined in the validation study
plan. Applicants must attest on the application that the data collection was performed as outlined in the
validation study plan.
The applicant hereby certifies that the data included with this application were collected as outlined in
the validation study plan.
Applicant (print name)
Applicant (signature) and (Date)
[Questions, comments or applications should be directed to:
S_teyen_C._Wende|kenj_PhD1
U.S. EPA, Office of Ground Water and Drinking Water-Technical Support Center
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
Phone:(513)569-7491
Fax:(513)569-7837
wendelken.steve@epa.gov]
A-2
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Appendix B: Standard EPA Method Format
[Note: Each method should be a free-standing document, providing all information necessary for the
method user to perform the method. References within a method should be restricted to associated or
source material. Procedural steps or instructions should not be referenced as being found elsewhere, but
should be included in totality within the method.]
1 Scope and Application
[This section outlines the purpose, range, limitations, and intended use of the method and identifies
target analytes.]
2 Summary of M-1 i iod
[This section provides an overview of the method procedure and quality assurance.]
3 Definitions
[This section includes definitions of terms, acronyms and abbreviations used in the method. If preferred,
definitions may be provided in a glossary at the end of the method or manual. In this case, the
definitions section should still appear in the method, with a notation that definitions are provided in a
glossary (refer to the specific section number of the glossary) at the end of the method.]
4 Interferences
[This section identifies known or potential interferences that may occur during use of the method and
describes ways to reduce or eliminate these interferences.]
5 :-J|.M\
[This section describes special precautions needed to ensure personnel safety during the performance
of the method. Procedures described here should be limited to those which are above and beyond good
laboratory practices. The section should contain information regarding specific toxicity of analytes or
reagents.]
6 Equipment and Supplies
[This section lists and describes all non-consumable supplies and equipment needed to perform the
method.]
7 Reagents and Standards
[This section lists and describes all reagents and standards required to perform the method and provides
preparation instructions or suggested suppliers or both as appropriate.]
8 !.'>['' i! , i %l I > "> ,11, .'I,! ^ i ^ ,
[This section provides requirements and instructions for collecting, preserving and storing samples.]
B-l
-------
[This section cites the procedures and analyses required to fully document the quality of data generated
by the method. The required components of the laboratory's quality assurance program and specific
quality control analyses appropriate to the method are described in this section. It should reference
Chapter VI, Critical Elements for Radiochemistry in "The Manual for the Certification of Laboratories
Analyzing Drinking Water" (Reference_6_m_Section_8) for the required quality control tests and the
specific quality control acceptance criteria for each of them.]
[This section describes the method or instrument calibration and standardization process and the
required calibration verification. Corrective actions are described for cases when performance
specifications are not met.]
11 Pro.. >!
[This section describes the sample processing and instrumental analysis steps of the method and
provides detailed instructions to analysts.]
12 Data Analysis and Calculations
[This section provides instructions for analyzing data, equations, and definitions of constants used to
calculate final sample analysis results and their uncertainties. For more information please refer to
Section 4.3.3 of this document.]
[This section provides method performance criteria for the method, including precision or bias
statements regarding DLs and sources or limitations of data produced using the method.]
! ii i H|"ii h I I * viiih >n
[This section describes aspects of the method that minimize or prevent pollution known to be or
potentially attributable to the method.]
15 M ,'i , 'i
-------
. ,'! !i -« iii ->|t, ,i i ii, -1 ,x! , |Mi!,! ip , 11 i -I uikinj
Matrix
1 Purpose and Scope
This standard operating procedure details the requirements for the preparation of the Test Matrix for
use in performing tests associated with the development of candidate radiochemistry methods for
application as an EPA ATP for Radiochemistry.
The Test Matrix applies only for use in developing Radiochemistry ATPs and should not be used as a
basis for assessment of other drinking water procedures.
2 Summary of Method
Prescribed salt solutions are added to deionized water conforming to ASTM Type I or II requirements.
The prepared Test Matrix is allowed to equilibrate for at least 16 hours. The result is a 1 liter sample of
approximately 350 ppm of total dissolved solids.
The Test Matrix is spiked as needed for the applicant's tests and acidified based on the radioanalyte of
interest per the requirements for sampling preservation cited in the Manual for the Certification of
Laboratories Analyzing Drinking Water -Criteria and Procedures Quality Assurance - 5th Edition, EPA
815-R-05-004, January 2005 (Reference 16.4).
3 i ' ii l , 1 1 fety Warnings
Laboratory safety procedures for handling reagents and chemicals are to be followed.
4 Definitions
None
'.'L'L''
1-L and 4-L containers to meet sample container requirements for specified drinking water
analysis, glass or plastic.
Top loading balance, maximum allowed mass at least 10,000 grams readability to 0.01 grams (10
mg).
ASTM Class 2 or equivalent calibration weight set with masses of 1, 2, 5, 10, 20 and 50 grams.
Pipette - volumetric, to deliver, 1 mL and 4 mL.
Spatula.
Stir plate- magnetic.
Stir bar - 40 mm magnetic.
250 mL volumetric flask, glass or plastic, to contain, Class A.
Weighing dish, polystyrene, minimal 40 x 40 x 8 mm.
C-l
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I ^ .;.,TU" ^
All reagents used are to be American Chemical Society grade or better.
Note: The following reagents may be substituted with equivalent salts of varying hydrated state. By
example: Barium chloride anhydrous may be substituted for barium chloride dihydrate, provided the
proper conversion has been made to adjust the water content of the salt for the elements of interest.
The determined ppm content of each of the salts is presented in labJeJJ (see Section 15).
Caution: ONLY the hydration state of the salts may be varied.
Aluminum Chloride Hexahydrate - American Chemical Society Grade.
Barium Chloride Dihydrate - American Chemical Society Grade.
Calcium Nitrate Tetrahydrate - American Chemical Society Grade.
Iron (III) Chloride - American Chemical Society Grade.
Magnesium Sulfate Heptahydrate - American Chemical Society Grade.
Potassium Chloride - American Chemical Society Grade.
Sodium Phosphate Dibasic - American Chemical Society Grade.
Sodium Bicarbonate - American Chemical Society Grade.
Sodium Sulfate, Anhydrous - American Chemical Society Grade.
Reagent Water - ASTM Type I or Type II.
7 i" i i! i! 1 1
None
1 1 1 i i i
Ensure balance is calibrated and that daily or monthly performance checks are performed as required by
the lab's standard operating procedures using acceptable weights for the masses to be measured (1 - 25
g).
9 ! ' | i ' ,1 '! I h
Once prepared let the solution stand for at least 16 hours prior to filtration. The solution is not to be
preserved until it has been spiked.
10 Prc-' ,\lin>:
a. Prepare each of the following stock standard reagents separately using reagent water and a 250
ml TC volumetric flask.
Note: The masses identified should be adhered to as closely as practical with no more than 10%
variance in the mass of the salt added. Therefore, a 1.0 gram addition may be allowed in
tolerance from 0.9 to 1.1 grams. The determined total dissolved solids of the solution and the
concentration of the contaminant will change accordingly. All weights used are to be
documented.
i. Aluminum Chloride Hexahydrate 4 mg/mL: Dissolve 1.0 g of AICI3»6H2O, dilute to 250
ml with reagent water.
C-2
-------
ii. Barium Chloride Dihydrate 4 mg/mL: Dissolve 1.0 g of BaCl2»2H2O, dilute to 250 ml with
reagent water.
iii. Calcium Nitrate Tetrahydrate, 40 mg/mL: Dissolve 10 g of Ca(NO3)2»4H2O, dilute to 250
ml with reagent water.
iv. Iron (III) Chloride, 4 mg/mL: Dissolve 1.0 g of FeCI3, dilute to 250 ml with water.
v. Magnesium Sulfate Heptahydrate, 100.0 mg/mL: Dissolve 25 g of MgSO4»7H2O, dilute to
250 mLwith reagent water.
vi. Potassium Chloride, 60 mg/mL: Dissolve 15 g of KCI, dilute to 250 mL with reagent
water.
vii. Sodium Bicarbonate 80 mg/mL: Dissolve 20 g of NaHCO3, dilute to 250 mL with reagent
water.
viii. Sodium Phosphate Dibasic Anhydrous, 14 mg/mL: Dissolve 3.5 g of Na2HPO4, dilute to
250 mL with reagent water.
ix. Sodium Sulfate Anhydrous, 60 mg/mL: Dissolve 15 g of NaSO4, dilute to 250 mL with
reagent water.
b. To constitute 1 L of test matrix, add 1 mL of each reagent to a 1 L glass or plastic TC volumetric
flask and dilute with reagent water to 1 Liter, swirling or stirring to mix.
c. To constitute 4 L of test matrix, add 4 mL of each reagent to a 4 L glass or plastic TC volumetric
flask and dilute with reagent water to 4 Liters, swirling or stirring to mix.
d. Transfer to an appropriate glass or plastic container with label for storage.
e. Allow solution to stand for at least 16 hours, then filter.
f. Determine the Total Dissolved Solids of the sample using an appropriate procedure.
g. Record the results of the Total Dissolved Solids analysis for submittal with the ATP application
package.
h. Spike the Test Matrix with a known concentration of the radioisotope of interest as required
based on proposed ATP protocol. Swirl to mix.
i. Record the date, time and spike isotope(s) and level(s).
j. Preserve the Test Matrix with acid as required based on proposed ATP requirements. Test and
adjust the pH of the Test Matrix to ensure that it meets drinking water sample requirements of
less than 2.0. Swirl to mix.
k. Record the preservative used, concentration, amount added and pH of the Test Matrix.
I. Allow the Test Matrix to stand for at least 16 hours prior to sample analysis.
11 Data Acquisitions, ( ! I ,. ' .'i ' ! ., , , "i ' "> ih" ^ "i
-------
Spiked or spiked and preserved Test Matrix solutions and Stock Standard Solutions are to be
disposed of in accordance with the testing laboratory's procedures and State regulatory
requirements.
14 Records Management
All records are to be reviewed and approved in accordance with laboratory approved
procedures and the laboratory's quality assurance project plan.
Copies of the records developed in the preparation and quality control of the Test Matrix are to
be provided with the records for supplied to EPA for the ATP application.
C-4
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ii l.s'. Charts
I -'Me 3. Test Matrix Solution Composition Chart
Chemical Compound
Utilized
Aluminum Chloride
Hexahydrate
Aluminum Chloride
Hexahydrate
Barium Chloride
Dihydrate
Barium Chloride
Dihydrate
Calcium Nitrate
Tetra hydrate
Calcium Nitrate
Tetra hydrate
Disodium Phosphate
Anhydrous
Disodium Phosphate
Anhydrous
Iron (III) Chloride
Iron (III) Chloride
Magnesium Sulfate
Heptahydrate
Magnesium Sulfate
Heptahydrate
Potassium Chloride
Analyte of Interest
Aluminum
Chloride
Barium
Chloride
Calcium
Nitrate
Sodium
Ortho Phosphate
Iron
Chloride
Magnesium
Sulfate
Potassium
Analyte to
Compound Mass
Ratio
0.11
0.44
0.56
0.17
0.17
0.53
0.32
0.67
0.34
0.66
0.10
0.39
0.52
Mass Added of
Compound in grams
1
1
1
1
10
10
3.5
3.5
1
1
25
25
15
ppm of Chemical
Compound Utilized
in Test Matrix
4.00
Not applicable
4.00
Not applicable
40.00
Not applicable
Not applicable
14.00
4.00
Not applicable
100.00
Not applicable
60.00
ppm of Analyte in
Test Matrix1
0.45
1.76
2.25
0.68
6.79
21.03
4.53
9.37
1.38
2.62
9.86
38.97
31.47
L Total Dissolved Solids is 298.70.
C-5
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Chemical Compound
Utilized
Potassium Chloride
Sodium Bicarbonate
Sodium Bicarbonate
Sodium Sulfate
Anhydrous
Sodium Sulfate
Anhydrous
Analyte of Interest
Chloride
Sodium
Carbonate
Sodium
Sulfate
Analyte to
Compound Mass
Ratio
0.48
0.27
0.71
0.32
0.68
Mass Added of
Compound in grams
15
20
20
15
15
ppm of Chemical
Compound Utilized
in Test Matrix
Not applicable
Not applicable
80.00
60.00
Not applicable
ppm of Analyte in
Test Matrix1
28.52
21.89
57.14
19.42
40.58
C-6
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.' viPi-Tices
40 CFR 141 National Primary Drinking Water Regulations
Protocol for the Approval of ATPs for Radiochemical Analytes
ASTM D1193-9961; Standard Specifications for Reagent Water; American Society for Testing and
Materials, March 1999 with editorial change made in October 2001
(EPA 815-R-05-004)
http://water.epa.gov/scitech/drinkingwater/labcert/methods_index.cfm.
C-7
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al I
Act
The detection capability of radiochemical measurements used for the Safe Drinking Water Act drinking
water compliance monitoring is specifically defined at 40 CFR part 141.25(c) as a DL It further defines a
DL with the following conditions:
"The DL shall be that concentration which can be counted with a precision of plus or minus 100
percent at the 95 percent confidence level (1.96o where o is the standard deviation of the net
counting rate of the sample)."
The Safe Drinking Water Act DL according to this definition differs from other "detection limits/' such as
the method detection limit or DL, (defined in 40 CFR part 136, Appendix B) and the minimum detectable
activity or Minimum Detectable Activity, which is commonly used by radiochemists. Required DLs for the
Safe Drinking Water Act drinking water compliance monitoring for radioactivity concentrations are
expressed in terms of the definition given in 40 CFR 141.25(c).
For measurements involving simple nuclear counting with Poisson counting statistics, the procedure
given in Section 2.0 below may be used to obtain a preliminary estimate of the Safe Drinking Water Act
DL.
Note: Many radiochemical measurements involve simple Poisson counting. However, since it is possible
that a submitted candidate method may involve measurement techniques with different statistics (for
example, gamma-ray spectrometry), laboratories should contact EPA before submitting their study plan
to determine if the equations in this appendix may be used to calculate the DL for the candidate method
they wish to propose for approval.
2
The definition of the Safe Drinking Water Act DL may be expressed mathematically as follows:
/?DL=1.96x<7DL (11)
Where:
RDL is the mean net count rate for a sample with concentration at the DL.
Ooiisthe standard deviation of the net count rate.
The relationship for the standard deviation of a radiochemical measurement is centered around the fact
the gross rate has a background rate subtracted from it to derive a net count rate.
RDL=RG-RB (12)
Where:
D-l
-------
RG is the mean gross count rate for a sample (with concentration at the DL).
RB is the mean background count rate for a sample measurement.
However, each count rate is a calculated quantity, as specified below.
^=^ and RB=^ (13)
'G 'B
Where:
RG is the mean gross count rate for a sample (with concentration at the DL).
RB is the mean background count rate for a sample measurement.
CG is the mean total (gross) sample count.
CB is the mean total background count.
tG is the time of the measurement used to accumulate the sample count.
tB is the time of the measurement used to accumulate the background count.
The standard deviation of a count rate is inversely proportional to the square root of the mean
of a measurement. Assuming Poisson counting statistics, the standard deviation of RG and RB are
given by:
and
-------
Equation 18 may now be solved algebraically for the value of RDL. First rewrite the radicand.
Square each side of the equation.
(19)
+l.96RX - + -
(20)
Collect all terms on the left-hand side to put the equation in standard quadratic form.
(21)
The quadratic formula gives two solutions to equation 21, one of which is positive and one of which is
negative. The positive solution is required and it is given by the following equation.
2tr
(22)
Equation (22) provides a reasonable estimate of the count rate at the DL for the net activity that is based
on counting statistics alone. This count rate should then be divided by the product of the experimental
factors, H, which can include the following items; the method of detection's counting efficiency, the
sample volume, gravimetric or tracer recoveries, conversion factors to picocuries, etc. The result can be
used to derive a specific DL of the radioanalyte of interest for a radiochemical method of analysis that is
used for the Safe Drinking Water Act compliance monitoring.
(23)
H
Where:
H is the product of the experimental factors.
DL is the Safe Drinking Water Act Detection Limit.
This DL is equivalent to the DL specified in 40 CFR part 141.25(c). It is expected that the experimental
factors will vary with each specific method.
D-3
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Appendix ! ' h ! i, ^
The following section provides examples in performing the necessary calculations for the determination
of sample data to meet the acceptance criteria established for the method.
1 Example Experimental Detection Limit Study
The instructions for performing the calculation in an experimental DL study are given in Section_4.6.1.
The following example illustrates how the evaluation criteria should be applied.
Suppose three laboratories participate in the DL study and that 21 artificially spiked samples at the same
concentration (^u) are analyzed, seven per laboratory, as suggested in Section_4.4.2.2. (These are the
minimum numbers of laboratories and samples permitted.). Assume that the required DL is 2.5 pCi/L and
the 21 samples are spiked at 2.5 pCi/L. Then:
m = 3.
n = 7.
u. = 2.5 pCi/L
In Table 4 the analysis results for the DL study from the three laboratories have been compiled and the
mean results determined.
Table 4. Example Detection Limit Study Results Spiked at 2,5 pCi/L
Lab (/)
1
2
3
1
1.06
1.77
2.37
2
3.04
0.419
-1.12
3
1.63
2.22
2.56
4
2.97
2.65
2.12
5
1.90
0.878
2.35
6
3.62
5.93
2.08
7
2.49
3.03
2.71
Xi
2.3871
2.4139
1.8671
Sample (/) Results in pCi/L
The last column in the table shows the arithmetic mean of the seven results for each of the three
laboratories, which is calculated using equation three in Section_4.6.L For example, the arithmetic mean
for the first laboratory is:
1.06 + 3.04 + 1.63 + 2.97 + 1.90 + 3.62 + 2.49 16.71
/
/
= 2.3871
(24)
Similar calculations are performed for the other two rows of the table.
After the three means are calculated a chi-square statistic is calculated for each laboratory using the
second part of equation three, as shown below.
-2 = 1.962 7
2.5 j=l
=2'9924
(25)
-2 _ 1.962
X2~^L?
:2-2.4139)2= 12.0406
(26)
E-l
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=6.5822 (27)
Each of the individual chi-square statistics is presumed to have the /2 distribution with six degrees of
freedom.
Next equation 4 of SectJQnJJiJ,, is used to calculate the overall chi-square statistic.
3
X2 =x? =2.9924 + 12.0406 + 6.5822 = 21.6151 (28)
This statistic has 18 degrees of freedom (three times six). So, the critical value for the statistic is the 99th
percentile of the ^-distribution with 18 degrees of freedom, which equals 34.81. Since the calculated
value of 21.6151 does not exceed 34.81, the method passes the experimental DL study.
2 Example i Vr i I M nh i Assessment Study
2.1 Bias
The instructions for performing the Method Performance Assessment study are given in Section_4.5_. The
evaluation criteria for the results are described in Sections 4.6.2 through 4.6.4. The following example
illustrates how the evaluation criteria should be applied.
Suppose that a method for the determination of Cesium-137 is being evaluated. For the method
performance study, three laboratories each analyze seven replicates at four different matrix and spike
level combinations, as listed below:
1) Reagent water, spiked at the Maximum Contaminant Level.
2) The test matrix, spiked at the Maximum Contaminant Level.
3) The test matrix, spiked at Yi the Maximum Contaminant Level.
4) The test matrix, spiked at 2 times the Maximum Contaminant Level.
The following example reflects the first set of data, reagent water spiked at the Maximum Contaminant
Level. For Cesium-137, the Maximum Contaminant Level is 200 pCi/L. Therefore, 21 artificially spiked
samples at 200 pCi/L of Cesium-137 are analyzed, seven per laboratory, as suggested in
(These are the minimum numbers of laboratories and samples permitted.). Therefore, m = 3, n = 7, /J =
200 pCi/L.
From JabJeJ (Section 4.6.2), ONELAC equals 1.5185 + (0.0347 * 200) = 8.46 pCi/L
Table 5 shows the analysis results of the method performance assessment study for the reagent water
samples spiked at the Maximum Contaminant Level, including the mean and standard deviation
determined for each laboratory.
E-2
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5. Example Method Performance Assessment Study Results Spiked at 200 pCii/IL
Lab (/)
1
2
3
1
188.80
180.85
203.47
2
203.00
201.05
195.37
3
204.22
177.59
182.03
4
202.55
191.61
193.51
5
200.13
202.28
191.07
6
220.62
192.29
210.22
7
203.19
198.92
173.07
Xi
203.2160
192.0841
192.6760
si
9.3233
9.7281
12.4678
Sample (/) Results in pCi/L
The pooled within-laboratory standard deviation, sw, is calculated as:
= jl(9.32332 +9.72812 +12.46782) = >/l 12.3360 =10.5989
The grand mean, X , equals.
X = -(203.2160 + 192.0841 + 192.6760) = 195.9921
3V '
The between-laboratory standard deviation, Sb is then calculated as:
(29)
(30)
sb =J-X [(203.2160-195.992l)2 +(192.0841-195.992l)2 + (192.6760-195.
= 4.8145
The ratio of between-laboratory to within-laboratory standard deviation, then equals:
4.8145
r =
= 0.4542
10.5989
The combined standard deviation equals.
|0.45422+-
a =8.46X1 ?- = 4.5509
0.45422 +1
Finally, upper and lower acceptance limits are calculated as:
1.7321
.5989^
(31)
(32)
(33)
206.78 (34)
E-3
-------
Therefore, the grand mean, X , should fall between 193.22 and 206.78. Because the grand mean,
195.99 pCi/L falls between the lower acceptance limit, 193.22 and the higher acceptance limit, 206.78,
the average concentration at the Maximum Contaminant Level for this method is acceptable.
2,2 Precision
The /2 statistic for total precision is calculated below:
195.9921) = 35.94 (35)
Because 35.94 is less than the 99th percentile of the chi-square distribution with 20 degrees of freedom
(37.57), the precision for this method at the Maximum Contaminant Level is acceptable.
Because both the bias and precision passed for the reagent water samples spiked at the Maximum
Contaminant Level, separate analyses would then be performed in the test matrix, with each sample
spiked at the Maximum Contaminant Level, ^Maximum Contaminant Level and 2*Maximum
Contaminant Level. The bias and precision at each of these concentrations would then be assessed and
if both tests pass at each spike level, the method would pass the method performance assessment
study.
E-4
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