[Federal Register Volume 69, Number 215 (Monday, November 8, 2004)]
[Proposed Rules]
[Pages 64704-64707]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-24824]


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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.

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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 [email protected].

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