[Federal Register: November 8, 2004 (Volume 69, Number 215)]
[Proposed Rules]
[Page 64704-64707]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08no04-23]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 136
[OW-2003-0003; FRL-7834-8]
Guidelines Establishing Test Procedures for the Analysis of
Pollutants; Procedures for Detection and Quantitation
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of document availability.
-----------------------------------------------------------------------
SUMMARY: EPA uses method detection limit (MDL) and minimum level of
quantitation (ML) procedures to establish detection and quantitation
capabilities of test procedures (i.e., analytical methods) under the
Clean Water Act (CWA). The MDL is used to determine the lowest
concentration at which a substance is detected or is ``present'' in a
sample. The ML is used to describe the lowest concentration of a
substance in a sample that can be measured with a known level of
confidence. Today's notice announces the availability of a document
entitled Revised Assessment of Detection and Quantitation Approaches.
This document presents EPA's revised assessment of MDL, ML and other
detection and quantitation procedures for use under the CWA, and EPA's
consideration of public comment received on an assessment document
published by EPA in 2003.
ADDRESSES: The docket for today's action is available under Docket ID
No. OW-2003-0003. All documents in the docket are listed in the EDOCKET
index at http://www.epa.gov/edocket. Although listed in the index, some
information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available either electronically in EDOCKET or in hard
copy at the Water Docket in the EPA Docket Center, (EPA/DC) EPA West,
Room B102, 1301 Constitution Ave., NW., Washington, DC. This Docket
Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday,
excluding legal holidays. The telephone number for the Public Reading
Room is (202) 566-1744, and the telephone number for the Water Docket
is (202) 566-2426.
FOR FURTHER INFORMATION CONTACT: William Telliard; Engineering and
Analysis Division (4303T); Office of Science and Technology; Office of
Water; U.S. Environmental Protection Agency; Ariel Rios Building; 1200
Pennsylvania Avenue, NW.; Washington, DC 20460, or call (202) 566-1061
or E-mail at telliard.william@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. How Can I Get Copies of This Document and Other Related Information?
1. Docket. EPA has established an official public docket for this
notice under Docket ID No. OW-2003-0003. The official public docket
consists of the documents specifically referenced in this notice,
public comments received on EPA's assessment presented in the February
2003 Technical Support Document, and other supporting information
related to this assessment. Information claimed as CBI and other
information whose disclosure is restricted by statute, or which is not
included in the official public docket, will not be available for
public viewing in EPA's public docket. The official public docket is
available for public viewing at the Water Docket in the EPA Docket
Center (EPA/DC), EPA West, Room B102, 1301 Constitution Ave., NW.,
Washington, DC 20460. This Docket Facility is open from 8:30 a.m. to
4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is (202) 566-1744, and the
telephone number for the Water Docket is (202) 566-2426.
2. Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the Federal Register
listings at http://www.epa.gov/fedrgstr/. An electronic version of the
public docket is available through EPA's electronic public docket and
comment system, EPA Dockets. You may use EPA Dockets at http://www.epa.gov/edocket/
to access the index listing of the contents of the
official public docket, and to access those documents in the public
docket that are available electronically. Once in the system, select
``Search,'' then key in the appropriate docket identification number.
Information claimed as CBI and other information whose disclosure is
restricted by statute, or which is not included in the official public
docket, will not be available for public viewing in EPA's electronic
public docket. EPA's policy is that copyrighted material will not be
placed in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. Although not all
docket materials may be available electronically, you may still access
any of the publicly available docket materials through the docket
facility identified in I.A.1.
II. Background
A. Test Procedures Used for Clean Water Act Programs
EPA proposes and promulgates test procedures at 40 CFR part 136 in
accordance with Section 304(h) of the CWA, which requires that the EPA
Administrator ``promulgate guidelines establishing test procedures for
the analysis of pollutants'' to be monitored and regulated under the
National Pollutant Discharge Elimination System (NPDES). Test
procedures are also
[[Page 64705]]
known as analytical methods. EPA draws the analytical methods from a
variety of sources, including methods developed by commercial vendors,
EPA and other government agencies, as well as methods from voluntary
consensus standards bodies such as the American Public Health
Association, the Water Environment Federation, and the American Water
Works Association, which jointly publish Standard Methods for the
Examination of Water and Wastewater; the Association of Official
Analytical Chemists; and the American Society for Testing and Materials
(ASTM) International. An analytical method promulgated by EPA under CWA
section 304(h) is considered approved by EPA for purposes of EPA's
NPDES permitting regulations.
Among considerations for approval of an analytical method at 40 CFR
part 136 are the demonstrated performance characteristics of precision,
bias, and sensitivity (i.e., detection and quantitation). EPA generally
evaluates each of these characteristics to determine if the analytical
method will yield results at concentrations of concern that are
reliable enough to meet Agency needs for permitting and compliance
monitoring under the Clean Water Act (CWA). Detection and quantitation
limits have been the most controversial of these characteristics,
particularly among members of the regulated community.
The method detection limit (MDL), which is specified at 40 CFR part
136, appendix B, is used to determine the lowest concentration at which
a substance is detected or is ``present'' in a sample. The minimum
level of quantitation (ML) is used to describe the lowest concentration
in a sample of a substance that can be measured with a known level of
confidence. The existing MDL procedure has been in place since 1984.
Individual MDLs and MLs are included in many EPA-approved methods at 40
CFR part 136, and have provided laboratories and data users with limits
for evaluating results of analytical measurements or analytical method
selection.
B. EPA's Initial Assessment
In 2003, EPA completed an initial assessment of approaches for
determining detection and quantitation capabilities of analytical
methods and their application to CWA programs, and published the
results in the Technical Support Document for the Assessment of
Detection and Quantitation Approaches (EPA-821-R-03-005, February
2003). This assessment examined EPA's current MDL and ML procedures, as
well as alternative detection and quantitation concepts and procedures.
A draft of the initial assessment document was peer-reviewed in
August 2002. EPA revised the document to incorporate comments from the
peer review. On March 12, 2003 (68 FR 11791), EPA made Technical
Support Document for the Assessment of Detection and Quantitation
Approaches available to the public and provided for 150 days for public
comment, including a 30-day extension of the comment period (68 FR
41988, July 16, 2003).
C. EPA's Revised Assessment
Today's notice announces the availability of the document entitled
Revised Assessment of Detection and Quantitation Approaches (the
Revised Assessment Document), EPA-821-B-04-005, October 2004. The
revised assessment examines the procedures currently used by the Agency
for determining detection and quantitation levels. It also evaluates
alternative concepts and procedures, including two detailed procedures
submitted by the U.S. Geological Survey (USGS) and the American Council
of Independent Laboratories (ACIL). ACIL is an organization
representing a large group of independent commercial laboratories.
This revised assessment evaluates several alternative concepts and
procedures, some of which were submitted during the comment period on
EPA's previous assessment. The Revised Assessment Document consists of
the following parts:
Chapter 1 provides background information regarding EPA's
assessment of detection and quantitation procedures.
Chapter 2 includes a discussion of additional concepts and
procedures not included in Technical Support Document for the
Assessment of Detection and Quantitation Approaches, February 2003.
Chapter 3 contains a summary of and general response to
public comments received on chemical, regulatory, and statistical
issues.
Chapter 4 addresses public comment on the six evaluation
criteria that EPA used to evaluate each of the detection and
quantitation procedures.
Chapter 5 contains an evaluation of detection and
quantitation procedures. It includes an evaluation of procedures
suggested by ACIL, USGS, and the Inter-industry Analytical Group.
Chapter 6 summarizes EPA's findings and outlines steps for
a continuing dialogue about detection and quantitation issues.
Appendix A contains a list of documents used in the
assessment.
Appendices B and C present analyses of the detection and
quantitation limit procedures. These analyses have been updated to
include data and comments submitted during the comment period on
Technical Support Document for the Assessment of Detection and
Quantitation Approaches, February 2003.
The Revised Assessment Document addresses comments and concerns
from stakeholders and peer reviewers. Based on this new information,
EPA plans to continue consideration of alternatives or improvements to
current detection and quantitation procedures and uses. It is clear
that there is a broad interest in improving current procedures and
uses, but no consensus for a specific procedure or procedures has
emerged among the laboratory, industry, regulatory or regulated
communities. EPA currently is soliciting stakeholders to participate in
further considerations of alternatives or improvements to current
detection and quantitation procedures.
D. Settlement Agreement
EPA conducted this revised assessment, and took comment on the 2003
assessment, to partially fulfill the requirements of a settlement
agreement with the Alliance of Automobile Manufacturers, et al. The
settlement agreement required that EPA assess existing Agency and
alternative procedures for determining detection and quantitation
limits and sign a notice for publication in the Federal Register on or
before February 28, 2003, and to invite comment on the assessment. On
March 12, 2003, EPA published: (1) A Federal Register notice announcing
the availability of, and requesting comment on, a document describing
EPA's assessment (68 FR 11791); and (2) a Federal Register notice
proposing and requesting comment on revisions to the MDL definition and
procedure at 40 CFR part 136, appendix B (68 FR 11770), and a
definition and procedure for calculation of an ML. EPA is discharging
its settlement agreement obligation today by making available a Revised
Assessment Document.
E. Proposed Rule; Withdrawal
In a separate notice published elsewhere in today's Federal
Register, EPA is withdrawing the March 12, 2003, proposal to revise the
MDL definition and procedure and to add a definition and procedure for
calculation of an ML. While EPA believes that some revisions to the MDL
definition and procedure are appropriate, the Agency also believes that
further work, including a stakeholder consultation process, is
[[Page 64706]]
needed before EPA can determine how best to address the concerns that
have been raised. EPA is exploring the feasibility and design of a
process through which stakeholders could provide their suggestions,
ideas and recommendations on procedures for the development of
detection and quantitation limits and uses of these limits in CWA
programs. The Agency believes that the body of public comment on the
proposed rule provides a strong starting point for a continued
consultation with stakeholders representing constituencies such as
citizens, environmental organizations, permit writers, regulators and
regulated industries. In a Federal Register notice published on
September 15, 2004 (69 FR 55547), EPA announced that a neutral party is
seeking a broad group of stakeholders willing to work together to
define and address concerns about the way detection and quantitation
values are calculated and used to support CWA programs. Such a process,
if feasible, could begin as early as December 2004.
III. Summary of Major Comments
EPA received many comment letters raising issues, concerns or
suggestions on Technical Support Document for the Assessment of
Detection and Quantitation Approaches. Commenters included
laboratories, wastewater treatment plants, Federal agencies, State and
county agencies, industrial firms, instrument manufacturers, trade
organizations, and others. A summary of public comments and EPA's
responses are included in the Response-to-Comments Document, which is
in the public docket supporting this notice (see Section I.A of this
notice).
A. EPA's Assessment
Although several commenters stated that EPA clearly put a great
deal of effort and thought into preparation of the initial assessment
document and commended EPA for its efforts, many commenters disagreed
with certain aspects of the assessment. Some specific concerns by
commenters are briefly discussed in the following paragraphs. A more
detailed discussion of commenters' concerns and suggestions is in the
Response-to-Comments Document or in the Revised Assessment Document.
1. Peer Review
In August 2002, a draft assessment document was peer-reviewed in
accordance with EPA's peer review policies, which are described in the
Science Policy Council Handbook (EPA 100-B-00-001). The draft document
was reviewed by a panel of four peer reviewers, who were selected
because of their expertise in the fields of statistics and/or
analytical chemistry and absence of conflicts of interest. The peer
review panel did not include any experts that directly or indirectly
contributed to the development of EPA's MDL or ML. The peer review
panel was generally supportive of EPA's approach and criteria, and made
some suggestions that were incorporated into the February 2003
document.
2. Evaluation of Data
Some commenters questioned EPA's analysis of the data used to
evaluate levels of detection and quantitation. They stated that they
were unable to replicate EPA's data evaluations and expressed confusion
regarding certain aspects of EPA's data handling (e.g., analytical
sequence, data censoring, and calculations using their suggested
quantitation procedure). In response to the comments that EPA's data
evaluations could not be replicated or were confusing, EPA has revised
or clarified the steps in its data evaluation in appendix B of the
Revised Assessment Document and/or in the Response-to-Comments
Document.
Some commenters submitted their evaluation of the data used by EPA,
while others submitted data and evaluations from other studies to
support the premise that their evaluations demonstrate that EPA's MDL
does not do what it purports to do, i.e., provide a one percent (1%)
false positive rate. In conducting the revised assessment, EPA
considered this new information and agrees that the one percent false
positive rate appears not to be achieved in some circumstances. EPA
will continue to study this issue and notes that other commenters
submitted a blank correction approach that could potentially improve
false positive rate performance under certain conditions, and which we
will explore in future consultations with stakeholders.
3. Evaluation and Selection of Alternative Concepts and Procedures
Several commenters stated that EPA inappropriately evaluated or
rejected the International Union of Pure and Applied Chemistry and the
International Standards Organization (IUPAC/ISO) critical value, and
ASTM's Committee D19 on Water Interlaboratory Estimate of Detection
(IDE) and Interlaboratory Estimate of Quantitation (IQE). Commenters
also criticized EPA's choice of evaluation criteria. EPA agrees that
some revisions to the evaluation criteria may be appropriate and will
explore this in future discussions with stakeholders.
EPA used the same evaluation criteria to evaluate all detection and
quantitation approaches, including the IUPAC/ISO and ASTM IDE/IQE
approaches. EPA did not reject either ASTM's approach or the concepts
adopted by IUPAC and ISO. As described in the Technical Support
Document for the Assessment of Detection and Quantitation Approaches,
EPA identified many approaches that have been used to describe the
sensitivity (i.e., the detection and quantitation capabilities) of
analytical methods. EPA had focused the 2003 assessment on four sets of
approaches that were either widely referenced or provided detailed
instructions for use in the laboratory. The four approaches were: (1)
ASTM's D19 committee IDE and IQE; (2) the LOD (limit of detection) and
LOQ (limit of quantitation) adopted by the American Chemical Society;
(3) the critical value, minimum detectable value, and limit of
quantitation adopted by IUPAC and ISO; and (4) EPA's MDL and ML
procedures. For the revised assessment, the Agency has expanded this
evaluation to include three additional approaches. These three
approaches were respectively submitted by the Inter-industry Analytical
Group, U.S. Geological Survey, and the American Council of Independent
Laboratories. The Revised Assessment Document also describes a
quantitation procedure that is being developed by EPA's Office of
Ground Water and Drinking Water. This quantitation procedure is known
as the minimum reporting level or MRL. The Agency anticipates proposing
the details of the MRL procedure in a rulemaking for public comment by
mid-2005.
Several commenters requested that EPA continue its assessment by
working with stakeholders to improve procedures for determining the
detection and quantitation capabilities of analytical methods. EPA
believes that there is benefit in continuing discussions and, in
section II.E. of this notice, describes the beginning of a process for
a series of discussions about these issues with stakeholders, such as
permitees, permit writers, state regulators, nongovernmental
organizations, and environmental groups.
B. Consensus Principles
Stakeholders commenting on EPA's 2003 assessment of detection and
quantitation approaches expressed their support of a set of ``consensus
principles'' submitted by 36 signatories.
[[Page 64707]]
The ``consensus principles'' described in this letter include the
following:
The definition of ``quantitation'' should account for both
precision and bias.
EPA should consider different uses of the MDL and ML in
the Clean Water Act program (as a start-up test for a single
laboratory, as a figure of merit to characterize an analytical method,
as a permit compliance level, etc.), and evaluate the applicability of
the MDL and ML to these uses.
Definitions of and procedures for determining quantitation
levels should take into account their use as regulatory compliance
levels in NPDES permits, and the effects of routine variability within
a laboratory on the results generated by the laboratory.
EPA notes that some of these ``consensus principles'' highlight
existing aspects of approaches to detection and quantitation and
provide a framework for future discussions with stakeholders. A more
detailed description and additional discussion of these ``consensus
principles'' is in Chapter 4 of the Revised Assessment Document.
C. Technical Issues
EPA considered, and is continuing to consider, several technical
issues related to the development of detection and quantitation
approaches. These issues are discussed in chapter 3 of the Revised
Assessment Document. Commenters expressed concern regarding EPA's
consideration of several of these technical issues, specifically how
these issues are, or are not, addressed by EPA's MDL and ML. Specific
concerns or suggestions expressed by commenters dealt with technical
aspects of EPA's assessment, such as treatment of sample blanks,
instrument data censoring, false positive and false negative rates, and
calculation of MLs. EPA addressed these comments in the Revised
Assessment Document and/or the Response-to-Comments Document, and the
Agency expects to further address these issues in a continued
consultation with stakeholders.
IV. Next Steps
It is clear that there is a strong interest in improving current
procedures and uses, but no consensus for a specific procedure or
procedures has emerged among the laboratory, industry, regulatory or
regulated communities. The Agency looks forward to working with
stakeholders. Based on an analysis of comments received on the 2003
assessment and proposed revisions to the MDL procedure, issues for
consideration in future stakeholder consultations may include, but are
not limited to, development of detection and quantitation procedures
that:
Vary in the nature and extent of statistical rigor and
laboratory performance checks depending on the end use of a calculated
limit in CWA programs;
Account for more sources of variability, such as the
variability between and within laboratories;
Require more then seven samples and collect samples over a
long period of time; and
Use routine blank samples collected over long periods of
time to account for background signals and temporal variability.
EPA has engaged a neutral third party to ask stakeholders for
suggestions for additional issues, and about their interest in working
with EPA to revise existing procedures and/or adopt one or more
alternative procedures.
Dated: November 1, 2004.
Benjamin H. Grumbles,
Acting Assistant Administrator for Water.
[FR Doc. 04-24824 Filed 11-5-04; 8:45 am]
BILLING CODE 6560-50-P