PROTOCOL FOR NATIONWIDE APPROVAL OF NEW OR REVISED
METHODS FOR INORGANIC AND ORGANIC ANALYTES IN NATIONAL
PRIMARY DRINKING RATER REGULATIONS MONITORING
Revision 1.5
January/ 1996
U.S. Environmental Protection Agency
Office of Research and Development
National Exposure Research Laboratory
Cincinnati/ Ohio 45268
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PROTOCOL FOR APPROVAL OF MEW OR REVISED
METHODS FOR INORGANIC AND ORGANIC ANALYTES IN NATIONAL
PRIMARY DRINKING RATER REGULATIONS MONITORING
INTRODUCTION
The Administrator/ U.S. Environmental Protection Agency (EPA),
approves analytical methods for all contaminants regulated under
the Safe Drinking Water Act (SDWA) . When EPA publishes a
regulation under the SDWA that sets a maximum contaminant level,
the regulation generally provides for at least one analytical
method for detection and/or quantification of that contaminant.
After any regulation is published/ EPA may approve additional
methods or modification to currently approved methods/ following a
set chemical method or microbiological method protocol of the ATP
program.
This protocol describes the information and data EPA needs to
evaluate an ATP for CHEMISTRY. The protocol is flexible in that
EPA's National Exposure Research Laboratory (NERL) may tailor the
criteria to a particular analyte, method/ and/or sample matrix.
For this reason/ before beginning the required testing, the
applicant is encouraged to discuss the application with EPA/NERL -
Cincinnati/ 26 West Martin Luther King Drive, Cincinnati/ Ohio
45268, to assure agreement on the testing design.
If the data evaluation demonstrates that the applicant's method
performs at least as well as the currently approved method, EPA
will recommend its approval to the Office of Ground Water and
Drinking Water, which begins the regulation development process.
Regulation development includes a Federal Register notice proposing
to approve an ATP/ public comment on the proposed method/ and
(depending on public comment) a final rule published in the Federal
Register approving the method. The regulation development process
may take about one year or more.
APPLICATION REQUIREMENTS
Any person may apply for nationwide approval of the use of
either a new method or an optional minor modification of a
previously promulgated method for a specific constituent in NPDWR
monitoring. Before submitting an application/ however/ the
applicant must provide a detailed write-up of the proposed method.
If the proposed method is very similar to an approved and
promulgated method/ and/or represents a minor optional change of an
approved method/ the applicant should simply prepare a two-column
side-by-side listing of the sections of the approved and proposed
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methods. This document should include the title/ identification
number and date of each method and all the topics in the EMMC
format provided in the Section, Method Description Requirements
beginning on page 2 of this document. The applicant should
highlight differences between the. proposed and approved methods.
If the method is an automation of a previously approved manual
method, any differences in kinetics and interferences should be
presented and a comparison of the final ratios of the reactants in
the proposed and approved methods should be included. This
information should then be forwarded to NERL-Cincinnati for review.
NERL-Cincinnati will recommend nationwide approval/disapproval of
the proposed method as: 1) identical to EPA's reference method, 2)
an optional minor modification of a previously promulgated method
or 3) significantly different method requiring an application for
an ATP as a new or revised method.
Every application for approval of a new method or optional
minor modification of a previously promulgated method shall be made
by letter in triplicate and forwarded to the Director, Ecological
Exposure Research Division - Cincinnati (NERL-Cincinnati), U.S.
Environmental Protection Agency, Cincinnati, Ohio 45268.
The general requirements for an application for nationwide
approval of any new or modified method include the name and
address of the applicant and/or authorized representative; the
contaminant for which the new or modified procedure is proposed;
justification for the proposed new or modified method; the title of
the method, company identification number and date of preparation
of the proposed method; and, a complete description of the proposed
method and of the approved method if used in a comparison. All
information provided to the Government is subject to the
requirements of the Freedom of Information Act. Any proprietary
information in the proposed method should be marked as
"Confidential". USEPA staff will handle all proprietary
information according to the regulations in subparts A and B of
Part 2 of Title 40 CFR.
Initially, an applicant should forward the above information,
except the comparability data, to NERL-Cincinnati. Upon receipt of
the application, the NERL-Cincinnati staff will assign an
identification number for the application, which should be used in
'all future communications. The NERL-Cincinnati staff will also
evaluate the submitted information and advise the applicant of the
specific comparability data requirements, if applicable.
Method Description Requirements
The method write-up must address the following topics listed
in the recently formulated Environmental Monitoring Management
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Council (EMMC) method format:1
1.0 Scope and Application
Include analyte identification; CAS number; sample type; method
sensitivity/ expressed as mass; and/ concentration range.
The range of the proposed method should be equal to or greater
than that of the approved method. If the range is smaller than
that of the approved method (particularly/ if the detection
limit is larger), NERL-Cincinnati may advise that the method
is inapplicable or the method may require a declaration of
method limitations.
2.0 Summary of Method
Describe scientific basis/ e.g./ chemical principles/
reactions/ and kinetics.
3.0 Definitions
4.0 Interferences
As a separate document/ include data observed by applicant
(during method development) using typical samples containing
a specific quantity of an interfering substance).
5.0 Safety
Refer to good laboratory practice/ appropriate material safety
data sheets/ and use of a hood/ goggles/ and/or protective
clothing. Emphasize any special procedure.
6.0 Equipment and Supplies
As separate documents/ include applicable manuals.
7.0 Reagents and Standards
Describe reagent formulations and shelf life of packaged
materials.
/
8.0 Collection, Preservation/ Shipment/ and Storage
See general guidance in laboratory certification manual2.
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9.0 Quality Control (QC)
Indicate need for a formal laboratory quality assurance/quality
control program; initial and periodic documentation of
performance by reporting results of analyses of reagent blanks/
check standards, and/or fortified samples; and, maintenance of
records, QC charts, etc. The periodic checking of performance
should preferably occur at a minimum frequency of 10% of the
total samples.
10.0 Calibration and Standardization
This section should include the calibration steps that are not
performed daily. Include the daily calibration step(s) in the
procedural section.
11.0 Procedure
Include in the method write up the procedural steps and the
daily calibration steps. As a separate document include a
typical calibration graph or curve.
12.0 Data Analysis and Calculations
13.0 Method Performance
Indicate the percent recovery, precision, and bias of the
method for typical samples, fortified with a known amount(s)
of the analyte. Include the method detection limits (MDL),
derived as outlined in Appendix B of section 136 of Title 40
of CFR, and expressed in weight/volume. The calculated MDL
should be confirmed by analyzing a samples at the calculated
MDL concentration. Note that the MDL should be equal to or
smaller than that of the approved method. If the MDL is
larger, NERL-Cincinnati may advise that the method is
inapplicable or the method may require a declaration of the
limited range of performance of the method.
14.0 Pollution Prevention
Cite good laboratory practices for pollution prevention.
15.0 Waste Management
Cite how waste and samples are to be disposed.
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16.0 References
Include reference to documents and publications.
17.0 Tables/ Diagrams/ Flowcharts, and Validation Data
Any proprietary information in the proposed method should be
marked "Confidential". USEPA staff will handle all proprietary
information according to the regulations in subparts A and B of
Part 2 of Title 40 of CFR.
Comparability Data Requirements
A method comparability study will be required for each new or
significantly revised method submitted for nationwide approval.
Guidance for the comparability study is provided in the following
text. Applicants are encouraged to have a brief consultation with
the NERL-Cincinnati ATP staff regarding specific comparability
study plans which may include the number of analyses, concentration
levels/ quality control (QC) activities/ performance evaluation
(PE) samples/ etc. If a major area such as the concentration range
of the proposed method differs from that of the approved method/
the applicant must consult with the NERL-Cincinnati ATP staff to
determine the appropriate modification of the comparability study
design. The required comparability data shall include measurements
of drinking water samples/ QC samples and PE samples. Initially/
each collected drinking water will be analyzed at least once by the
approved method to determine the concentration of the constituents
of interest and need for sample dilution and/or fortifying to
achieve the 5 x MDL baseline concentration as detailed in the
Subsample Preparation Requirements (pp. 6-7). After appropriate
preparation/ the subsamples of each drinking water will be analyzed
by both the approved and proposed methods.
The QC samples and the PE samples are to be prepared in reagent
water and used to determine if the laboratory is in control. PE
samples of known analytes/ but of concentration unknown to the
analyst/ will be provided by NERL-Cincinnati along with
instructions for use. The analyst is responsible for preparing the
/final QC and PE sample solutions for analyses. The QC and PE
solutions must be spaced every tenth sample among the drinking
water samples which are to be analyzed by both methods.
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As general guidance, the minimum number of analyses required
are summarized in the following table. However, depending on the
particulars of the method under review, the number of analyses may
change. We strongly suggest consultation with the NERL-Cincinnati
ATP staff prior to analyses.
Approval
type
Applicant
Drinking water sample or
subsample analyses per
regulated constituent
QC\PE
Samples
Total
Initial Adjusted Forti-
screen to 5 MDL fied
Nationwide Any 10 60 120-180 22-25 212-275
Drinking Water Sampling Requirements
For each constituent of interest, the applicant must collect
a minimum of ten drinking water samples, ideally one from ten
geographically-dispersed drinking water supplies. Six of these
supplies should be from surface water sources and four from ground
water sources. The supplies should contain variable water quality
characteristics that may affect the analyses. These include pH,
TOC, alkalinity, and TOX. We strongly suggest consultation with the
NERL-Cincinnati ATP staff prior to sampling.
An applicant is required to diligently select a source and/or
time of collection that will afford an analyte concentration as
close as possible to 5 times the published MDL of the approved
method. (If the MDL is unpublished, determine as directed in topic
13 on pp. 4). This sample selection will enable the preparation
of the required subsamples by either dilution or fortifying with a
minimum of alteration of sample matrix.
Most samples should be collected using the containers,
preservation techniques, and holding times outlined in the approved
methods. Samples for asbestos, barium, cadmium, chromium,
fluoride, mercury, nitrate, nitrite, and selenium analyses should
be handled as outlined in the Phase II regulations2.
Subsample Preparation Requirements
The bias, precision, percent recovery and MDL of the proposed
method will be compared to those of the approved method. Several
levels of concentrations covering the performance range of the
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proposed method will be used in the study. Ideally, the range of
the concentrations for the proposed method will be the same as the
approved method. The concentrations should include a level that is
5 X MDL, a level that is twice the maximum contaminant level and
additional levels that take into account the method range. This
issue must be addressed with the NERL-Cincinnati ATP staff prior to
analyses.
The study experimental design initially requires a single
analysis of each of the collected samples by the approved method to
determine the concentration of the constituents of interest. If
the initial concentration of constituents in any collected sample
differs significantly from the 5 x MDL level, the sample must then
be either diluted or fortified to achieve the 5 x MDL level.
Dilution must be done using deionized distilled water. Sample
fortifying must be accomplished using a substance whose character
reflects the nature of the analyte in the drinking water and/or the
calibration standards. For example/ in an application for mercury,
the fortifying substance should consist of a mixture of an
inorganic and an organic mercury compound. All of the initial
dilution or fortification (to achieve the desired 5 x MDL
concentration) must be performed before splitting a sample into
subsamples. Otherwise, the analytical error of each analysis may
also include the error of the individual dilution or fortification
of the subsamples and the data comparison may be inappropriate.
Record and report the initial dilution or fortifying required to
adjust each sample concentration to the 5 x MDL level.
The fortification of each subs ample must also be performed
before aliquoting for analysis. Otherwise, the analytical error
will include any individual fortification error and the comparison
data may be inappropriate. Record and report the amounts of the
substance added to each fortified subsample and the theoretical
total concentration in each subsample. The latter is calculated
for subsample by adding the mean of the triplicate analyses of the
subsample by the approved method to the amount of substance added
to that subsample. The evaluation of the comparability of the
proposed method is dependent upon the analyst's preparation and
analysis of corresponding subsamples with very similar
concentration.
Laboratory Requirements
It is highly desirable to have one laboratory analyze all of
the samples required in the study design. This is to eliminate the
effects of multiple laboratories on the comparison of data between
methods. Analyses by an additional laboratory should be included
as a QC check but these data are in addition to the required ATP
comparative analyses by the primary laboratory. This option should
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be discussed with the ATP staff. Preferably, the laboratory should
be independent. NERL-Cincinnati will judge on the appropriateness
of the suggested laboratory.
Approved Method Selection Requirements
Since the approval of a method'depends upon the comparability
of the bias and precision of the proposed method to that of an
approved method, the applicants's analyses by the approved method
must also be examined to determine their acceptability as a basis
in the comparison. This acceptability will be determined by
evaluating the applicant's analyses of QC and PE samples by both
the approved method and the proposed method.
The criteria used in the evaluation will be derived from
available regulations, text of the approved method, and/or various
interlaboratory validation and/or PE studies. USEPA may,
consequently, limit the applicant's choice of an approved method to
insure that the approved method used in the study is one which has
been evaluated with sufficient frequency in the interlaboratory
studies to afford an appropriate data base with which to determine
the acceptability of the applicant's analyses by the approved
method.
Drinking Water Subsample Analysis Requirements
As general guidance, applicants for nationwide approval of a
new or significantly revised method must perform six analyses of
each subs ample, three by the approved method and three by the
proposed method. The drinking water sample, drinking water
subsample, and analysis requirements are summarized in the
following table:
Approval Applicant No.of No.of Total No. No.of Total No.
collected subsamples samples repli- of
samples per for cate analyses
Collected analysis analyses
Sample per sub-
sample
per each
of two
methods
Nationwide Any 10 3-4 30-40 3 180-240
The aforementioned QC analyses should be performed along with
the analyses of the drinking water subsamples (see Comparability
Data Requirements, p. 5) .
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Data Reporting Requirements
Initial single observation of each collected sample by the
approved method, the initial dilution and/or fortifying of each
collected sample, the quantity of substance added to each subsample
and the total theoretical concentrations of the subsamples, the
replicate observations of all subsamples by both methods, and the
quality control observations must be forwarded to USEPA. A
suggested format for reporting the observations of each set of
subsamples is attached. The quality assurance observations
associated with each set of subsample observations should also be
tabulated and identified. An evaluation of the application can be
accomplished more quickly by the NERL-Cincinnati program and
statistical staff, however, if the information is also forwarded on
a floppy disc compatible with an IBM-PC computer. The text on the
disc should be presented in the latest version of WordPerfect
(currently, 6.0) and the data may be presented in WordPerfect or in
ASCII.
DATA REVIEW AMD METHOD RECOMMENDATION
Upon receipt of the applicant's data sets, NERL-Cincinnati
staff will initiate its technical and statistical reviews.
Appropriate criteria, derived either from published regulations or
from interlaboratory studies, will be used to determine the
acceptability of the approved method data as a basis in the
evaluation of the analyses by the proposed method. If this
evaluation is favorable, the evaluation of the comparability of the
proposed method will follow. (If the results of the analyses by
the approved method are not satisfactory, the applicant will be
notified that the application has been defaulted.)
Since the sampling and analytical requirements for each
application for approval of a new or significantly revised method
are based on a factorial experimental design with three factors,
namely, method, sample matrix, and constituent concentration, each
comparability review will be conducted over the range of these
three factors. Descriptive statistics, such as the mean, standard
deviation, coefficient of variation (relative standard deviation),
and percent recovery of each set of replicates will be calculated.
The precision of the proposed method will be compared with that of
the approved method by means of a nonparametric statistical
procedure attributable to Scheffe. An analysis of variance (ANOVA)
will be used to compare the recovery of the proposed method with
that of the approved method.
Upon completion of the technical and statistical reviews, NERL-
Cincinnati will prepare its recommendation for approval/disapproval
of the new or significantly revised method, notify the applicant of
its recommendation, and forward the recommendation to the Office of
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Ground Water and Drinking Water (OGWDW), which has the
responsibility of proposing the method in the Federal Register.
After a three-month public comment period, OGWDW will review any
submitted comments and prepare the final nationwide
approval/disapproval decision and notice in the Federal Register.
If you have any questions regarding the requirements/
especially the comparability study design and sample fortifying,
please contact the NERL-Cincinnati ATP staff at 513-569-7307.
REFERENCES
1. Villa, 0. and L. Reed, Co-Chairs, EMMC Methods Integration
Panel. Final Version of Approved EMMC Format (Memorandum to
Members of EMMC Steering Committee, Methods Integration Panel
and Work Group, Tri-Chairs). U.S. Environmental Protection
Agency, February 14, 1992, pp. 1-2.
2. Federal Register, Vol. 56 (20), part 141.23(lc)(4), pp. 3582-
3583. Wednesday, January 30, 1991.
10
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ATTACHMENT
Application No:,
(EPA Assigned)'
NPDHR COMPARABILITY STUDY DATA
Source or Water Supply Identity:
Drinking Water Source Type: Ground
Constituent Identity: •
Surface
Concentration Units (weight/volume):
Initial Sample Constituent Cone. (Before Adjustment).
or by Fort1fy1ng_
Initial Sample Adjustment
by D11ut1on_
(specify )
(spec1fy we1ght/volume)
Theoretical Cone.
Approved Method Observations
Proposed Method Observations
Sub-
samp
1
2
3
4
Amount
Added4
0
Total
Cone *
Replicate
1
Replicate
2
Replicate
3
Replicate
1
Replicate
2
Replicate
3
* Identify the applicant or source of data ONLY by the EPA-assigned application number.
+ See pp. 7-9 of the protocol for a discussion of how these concentrations are derived.
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