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Guidelines Establishing Test Procedures for the Measurement of Mercury in Water (EPA Method 1631, Revision C); Final Rule, Technical Corrections

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Information about this document as published in the Federal Register.

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Environmental Protection Agency (EPA).


Final rule; technical corrections.


EPA is amending the “Guidelines Establishing Test Procedures for the Analysis of Pollutants” to make minor technical corrections to clarify the use of field blanks for mercury testing under the Clean Water Act. Specifically, the amendments rectify an omission in the text of the promulgated version of Method 1631: Mercury in Water by Oxidation, Purge and Trap and Cold Vapor Atomic Fluorescence Spectrometry.


These technical corrections are effective July 18, 2001. The incorporation by reference of the publication listed in today's rule is approved by the Director of the Federal Register as of July 18, 2001. For judicial review purposes, this rule is promulgated as of 1:00 p.m. (Eastern time) on July 2, 2001, as provided in 40 CFR 23.2.

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For information regarding this rule contact Dr. Maria Gomez-Taylor, Engineering and Analysis Division (4303), USEPA Office of Science and Technology, Ariel Rios Bldg., 1200 Pennsylvania Ave., NW., Washington, DC 20460 (e-mail:

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Potentially Regulated Entities

EPA Regions, as well as States, Territories and Tribes authorized to implement the National Pollutant Discharge Elimination System (NPDES) program, issue permits that comply with the technology-based and water quality-based requirements of the Clean Water Act. In doing so, the NPDES permitting authority, including authorized States, Territories, and Tribes, make a number of discretionary choices associated with permit writing, including the selection of pollutants to be measured and, in many cases, limited in permits. If EPA has “approved” standardized testing procedures (i.e., promulgated through rulemaking) for a given pollutant, the NPDES permit must include one of the Start Printed Page 32775approved testing procedures or an approved alternate test procedure. Regulatory entities may, at their discretion, require use of this method in their permits. Therefore, entities with NPDES permits could be affected by the standardization of testing procedures in this rulemaking, because NPDES permits may incorporate the testing procedure in today's rulemaking. In addition, when a State, Territory, or authorized Tribe provides certification of Federal licenses under Clean Water Act section 401, States, Territories and Tribes are directed to use the standardized testing procedures. Categories and entities that may ultimately be affected include:

CategoryExamples of potentially regulated entities
Regional, State and Territorial Governments and TribesStates, Territories, and Tribes authorized to administer the NPDES permitting program; States, Territories, and Tribes providing certification under Clean Water Act section 401; Governmental NPDES permittees.
IndustryIndustrial NPDES permittees.
MunicipalitiesPublicly-owned treatment works with NPDES permits.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. This table lists the types of entities that EPA is now aware could potentially be affected by this action. Other types of entities not listed in the table could also be affected. If you have questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section.

Administrative Procedure Act

Section 553 of the Administrative Procedure Act, 5 U.S.C. 553(b)(B), provides that, when an agency for good cause finds that notice and public procedure are impracticable, unnecessary or contrary to the public interest, the agency may issue a rule without providing notice and an opportunity for public comment. EPA has determined that there is good cause for making today's rule final without prior proposal and opportunity for comment because today's rule merely corrects the text of a promulgated test method to reflect the Agency's intentions at the time it originally published the rule. Omissions to EPA Method 1631, Revision B, were brought to the Agency's attention by the members of the public after the test method was promulgated. The revisions to the test method clarify the use and reporting of field blanks, and are consistent with the discussion in the preamble to the final rule. In addition, this rule corrects a typographical error at 40 CFR Part 136.3(b). The CFR contains two references with the same number [(b)(40)]. The second reference (40) in Section 136.3(b) has been renumbered (41) and reference (41) has been renumbered (42). The revisions to the test method and the CFR are not substantive. Thus, notice and public procedure are unnecessary. EPA finds that this constitutes good cause under 5 U.S.C. 553(b)(B).

I. EPA Method 1631, Revision B

EPA promulgates analytical methods for pollutants under Clean Water Act programs at 40 CFR Part 136. In most cases, EPA has approved use of more than one analytical method for measurement of particular pollutants, and laboratories may use any approved test method for determining compliance with applicable requirements. From time to time, EPA amends 40 CFR Part 136 to approve new test methods or modifications to approved test methods. For new test methods or for substantive changes to approved test methods, EPA first publishes a notice for public comment and reviews any public comments received prior to making a final decision on approval.

EPA proposed Method 1631: Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry on May 26, 1998 (63 FR 28867), and then, after revisions following public comment, EPA promulgated Method 1631, Revision B on June 8, 1999 (64 FR 30417). On October 19, 2000, EPA entered into a Settlement Agreement to resolve litigation over the final rule in Alliance of Automobile Manufacturers, et al. v. EPA, No. 99-1420 (D.C. Cir.).

Under the Settlement Agreement, the Agency agreed to revise sections 12.4.2 and of the test method to clarify the use of field blank subtraction (section 12.4.2) and the use of multiple field blanks (section to determine whether test samples should be used for compliance monitoring purposes. At the time EPA published the challenged rulemaking, the Agency had intended to incorporate these changes into the rule, as reflected by the preamble and the comment-response document in the public record. The version of Method 1631 promulgated today now incorporates these technical corrections. No other changes are being made to the text of the referenced test protocol.

EPA will take actions to implement other provisions of the Settlement Agreement separately. For example, EPA agreed to propose additional clean techniques and quality control requirements for EPA Method 1631 in a Federal Register notice that is scheduled for signature by September 15, 2001. Today's action only addresses the use and reporting of field blank results.

Today's rule contains only minor technical corrections to EPA Method 1631, Revision B and provides a revised version reflecting these technical corrections. As required by the Office of the Federal Register, EPA submitted a revised version of the test method to the Director of the Federal Register for approval for incorporation by reference. The revised version submitted to the Director is EPA Method 1631, Revision C. In today's rule, the full reference to the test method in 40 CFR 136.3(b)(40) is being amended to reflect the updated test method (i.e., Revision C).

By today's action, EPA has revised the following sections of EPA Method 1631:

A. Section This text is revised to clarify that, if sufficient multiple field blanks (a minimum of three) are collected, and the average concentration (of the multiple field blanks) plus two standard deviations is equal to or greater than the regulatory compliance limit or equal to or greater than one-half of the level in the associated test sample, results for associated test samples may be the result of contamination and may not be reported or otherwise used for regulatory compliance purposes.

B. Section 12.4.2: This text has been revised to clarify that results for mercury in samples, reagent blanks and field blanks must be reported separately. In addition, if blank correction is requested or required by a regulatory authority or in a permit, the concentration of mercury in the reagent blank or the field blank is subtracted from the concentration of mercury in Start Printed Page 32776the sample to obtain the net sample mercury concentration.

Based on the preamble text for the June 8, 1999, final rule and the response to comments document that supports the final rule, it is apparent that the Agency intended to allow for field blank subtraction and for not using test sample results for regulatory compliance if multiple field blanks do not meet the specifications at This correction does not add any new requirements to the regulated community. To the contrary, it provides additional flexibility by allowing the use of field blank subtraction and by not requiring the reporting of test samples that may be contaminated based on results from field blank analyses. The rest of EPA Method 1631 is unchanged from the previously promulgated EPA Method 1631, Revision B.

II. Administrative Requirements

This technical correction action does not involve technical standards; thus, the requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) do not apply. This rule does not impose an information collection burden under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). EPA's compliance with these statutes and Executive Orders or their predecessors for the underlying rule is discussed in the June 8, 1999 Federal Register notice (64 FR 30417).

The Congressional Review Act (5 U.S.C. 801 et seq.), as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. Section 808 allows the issuing agency to make a rule effective sooner than otherwise provided by the CRA if the agency makes a good cause finding that notice and public procedure is impracticable, unnecessary or contrary to public interest. This determination must be supported by a brief statement. 5 U.S.C. 808(2). As stated previously, EPA has made such a good cause finding, including the reasons therefor, and established an effective date of July 18, 2001. EPA will submit a report containing this rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of the rule in the Federal Register. This action is not a “major rule” as defined by 5 U.S.C. 804(2).

III. Materials Incorporated by Reference Into 40 CFR Part 136

USEPA, 2001. Method 1631, Revision C: Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry. March 2001. U.S. Environmental Protection Agency, Engineering and Analysis Division, Office of Science and Technology, Washington, DC. EPA-821/R-01/024.

IV. Public Availability of Materials

The full text of Method 1631, Revision C incorporated by reference in today's rulemaking will be available to the general public from the following sources:

Water Docket: Paper version of the method, along with the public record for this rule and the Method 1631 final rule, are available for review under docket number W-98-15 at the U.S. Environmental Protection Agency, Water Docket, 401 M Street SW., Washington, DC 20460. For access to these materials, call 202-260-3027 on Monday through Friday, excluding Federal holidays, between 9:00 a.m. and 3:30 p.m. Eastern Time for an appointment.

Internet: This Federal Register rule also is available on the Internet at:​fedrgstr. An electronic version of Method 1631, Revision C is available via the Internet at​OST.

National Technical Information Service (NTIS): Electronic or paper version of Method 1631, Revision C (NTIS Publication No. PB2001-102796) is available from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161, by phone at 1-703/487-4650, fax at 1-703/321-8547, or via the Internet at

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List of Subjects in 40 CFR Part 136

  • Environmental protection
  • Analytical methods
  • Incorporation by reference
  • Reporting and recordkeeping requirements
  • Water pollution control
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Dated: June 6, 2001.

Diane C. Regas,

Acting Assistant Administrator for Water.

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For the reasons set out in the preamble, title 40, chapter I of the Code of Federal Regulations, is amended as follows:

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1. The authority citation for Part 136 continues to read as follows:

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Authority: Secs. 301, 304(h), 307, and 501(a) Pub. L. 95-217, 91 Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (The Federal Water Pollution Control Act Amendments of 1972 as amended by the Clean Water Act of 1977.)

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2. Section 136.3 is amended as follows:

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a. Redesignate paragraph (b)(41) as paragraph (b)(42);

b. Redesignate the second paragraph (b)(40) as new paragraph (b)(41) and revise it to read as follows:

Identification of test procedures.
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(b) * * *

(41) USEPA. 2001. Method 1631, Revision C, “Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry.” March 2001. Office of Water, U.S. Environmental Protection Agency (EPA-821-R-01-024). Available from: National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161. Publication No. PB2001-102796. Cost: $25.50. Table IB, Note 43.

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[FR Doc. 01-15145 Filed 6-15-01; 8:45 am]