Policy for the Approval of U.S. Geological Survey (USGS) Water-Quality Analytical Methods
To: " WRD Archive File, "
CC: Nana Snow ,
Iris Collies
Subject: Re: OWQ Tech Memo 98.05--Policy for the Approval of (USGS) Water-Quality
Analytical Methods
In Reply Refer To:
Mail Stop 412 September 14, 1998
OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM 98.05
Subject: Policy for the Approval of U.S. Geological Survey (USGS)
Water-Quality Analytical Methods
I. Purpose of Memorandum
This memorandum restates the Water Resources Division (WRD) policy for
the approval of water-quality analytical methods contained in WRD
Memoranda 82.28 and 92.37 and supersedes both memoranda. It also includes
a description of the process and requirements for obtaining WRD approval
of a water-quality analytical method by the Office of Water Quality
(Attachment 1).
II. Policy
All water-quality analytical data that are collected by the WRD on a
routine, production basis for release to the public in data reports,
district annual data reports, and data bases must be produced using WRD
approved methods by a laboratory that has been approved by WRD according
to OWQ Memorandum 98.03. This policy has been established to ensure that
USGS data are of known and documented quality, and that the analytical
methods used to produce the data are thoroughly tested, documented, and
available to the public.
Data produced using new, unapproved methods or using research methods may
not be published in data reports or in district annual data reports. In
addition, the data may not be released to the public in publicly
accessible data bases. Data provided to the public from unapproved
methods or research methods must be accompanied by a method description
that documents the method and the quality of the data reported.
III. Sources of Approved Methods
Any methods already accepted and published by the following sources will
have automatic WRD approval:
a. Methods published by the U.S. Environmental Protection Agency (USEPA)
b. Methods published by ASTM
c. Standard Methods (American Public Health Association, 1995)
New methods or modifications of existing methods that are not published
in the sources above must be published in one of the following USGS
series publications: Techniques of Water-Resources Investigations (TWRI)
series; Open-File Reports (OFR); or Fact Sheets.
REFERENCES:
American Public Health Association, American Water Works Association, and
Water Environment Federation, 1995, Standard methods for the examination
of water and wastewater (19th ed.): Washington, D.C., American Public
Health Association, variously paged.
Hansen, 1991, Suggestions to authors of the reports of the United States
Geological Survey. (7th ed.): Washington, D.C., U.S. Geological Survey,
289p.
U.S. Environmental Protection Agency, 1994, Guidelines establishing test
procedures for the analysis of pollutants (App. B, Part 136, Definition
and procedures for the determination of the method detection limit): U.S.
Code of Federal Regulations, Title 40, revised as of July 1, 1994, p.
635-637.a users.
CITED MEMORANDA
Office of Water Quality Technical Memorandum No. 98.03 (Revised): Policy
for the Evaluation and Approval of Production Analytical Laboratories.
April 16, 1998.
Water Resources Division Memorandum No. 82.28 (Superseded): Water
Quality-Acceptability and Use of Water-Quality Analytical Methods.
January 21, 1982.
Water Resources Division Memorandum 92.37 (Superseded): Policy of the
Water Resources Division on Laboratory Analytical Methodology. April 16,
1992.
Janice R. Ward
Acting Chief, Office of Water Quality
This memorandum supersedes Water Resources Division Memoranda No. 82.28
and 92.37.
Distribution: A, B, S, FO, PO
District Water-Quality Specialists
OWQ Staff
Regional Water-Quality Specialists
Key words: analytical method, data base, laboratory, water quality
Attachment 1: Process for Obtaining Approval of New Water-Quality
Analytical Methods
Definitions:
1. "Water-quality analytical methods" are chemical, biological, or
physical methods used to measure various properties of hydrologic systems
for purposes of assessing water quality.
2. "Hydrologic systems" include precipitation, surface water, and ground
water, along with associated atmospheric, biological, and geologic
components.
"Data" refer to the results of the measurements on a hydrologic system
using the water-quality analytical method. Results are typically
quantifiable numbers, such as analyte concentrations, biological species
names and numbers, and grain size or turbidity.
3. "Approved data" are the results of an approved water-quality
analytical method conducted by an approved laboratory under the
quality-assurance (QA)/quality-control specifications of the method.
These data may be published in District data reports and/or distributed
to the public through data bases.
4. "Analyte" refers to a constituent, element, isotope, or compound
being determined in a chemical analysis.
5. "Data quality" refers to the properties of the measurement, such as
precision, bias, detection limit, and other relevant measures.
6. "Final draft report" is a WRD report which has completed full
editorial and technical peer review according to normal USGS report
standards (Hansen, 1991) and is ready to be submitted for USGS approval.
Process for Obtaining Approval of New Methods:
Any laboratory providing data to WRD can request approval of a new
water-quality analytical method by submitting the following to the Chief,
OWQ:
1. A cover memorandum to the Chief, OWQ, from the originating laboratory,
through the appropriate WRD supervisory chain-of-command, asking for
approval of the method and describing why the method should be approved
by WRD. The originating laboratory must also be approved by WRD
according to OWQ Technical Memorandum 98.03.
2. A final draft WRD report, describing the water-quality analytical
method. The USGS standard manuscript-routing sheet (Hansen, 1991, p. 40),
including all signatures, up to final WRD approval must be included,
along with all technical peer-review comments and the author's responses
to those comments. At least one of the peer reviewers must be a
technical expert from outside the originating laboratory.
3. The originating laboratory's standard operating procedure (SOP) for
the method in the form and content specified by the originating
laboratory's QA manual.
Submittals will be reviewed by the OWQ within 3 weeks. All supporting
data and calculations related to the draft report shall be available for
review upon request. Any required changes will be communicated back to
the originator in writing. The manuscript routing sheet will be signed by
the Chief, OWQ, and returned to the originating laboratory for final
report approval.
Upon acceptance of the water-quality analytical method, and contingent
upon approval of the report draft by USGS, a memo from the OWQ will be
written to document the method as approved by WRD.
Approval of a new method requires documentation of method performance,
which shall include three different matrices; two different
concentrations, one high and one low; and seven replicates of each
combination. All analytes shall be spiked into each matrix. For water
methods, the three matrices should include a surface water, a ground
water, and a reagent water matrix. In some instances, specific
water-quality variables, such as conductivity or dissolved-organic
carbon, may be known to have substantial effects on the performance of
analytical methods. Specific consideration should be given to selecting
water sources that span expected ranges of those key variables. For
other media, the laboratory should choose three different representative
matrices that are appropriate.
The laboratory method blank shall be fully characterized. An initial
method detection limit (MDL) shall be determined according to the USEPA
(1994), and must include necessary iterations as specified therein. Data
for the MDL determination shall include data collected over several days
using different calibration curves. Reporting conventions for the
analytical data will be specified and justified, including numbers of
significant figures for different analyte concentration ranges. Values
reported for non-detections of each analyte will also be specified and
justified.
Process for Obtaining Approval for Modifications to Existing Approved
Methods:
Changes to WRD-approved water-quality analytical methods must be tightly
controlled. To maintain data quality, method changes expected to affect
data quality must be documented as a new water-quality analytical method
with full validation in a new USGS publication as described above. On
occasion, it may be appropriate to add analytes to an existing approved
water-quality analytical method. These changes require documentation
through a USGS publication using the same procedures outlined for the
original method approval.
Changes to approved water-quality analytical methods that are not
expected to affect data quality must be documented in changes to the
laboratory's SOP for that method. These changes shall be recorded as SOP
version number changes, with all supporting data archived with the method
file as specified in the laboratory's QA manual. These files must be
available to data users who may need to investigate unexpected
data-quality changes. Data changes resulting from recalculation or
reinterpretation of old analytical information must also be fully
documented in the laboratory-method file and be available for data users.
On a yearly basis, a copy of all updates to the method file shall be sent
to the Chief, Branch of Quality Systems, for tracking and availability to
the USGS and the public.
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