[Federal Register Volume 66, Number 195 (Tuesday, October 9, 2001)]
[Proposed Rules]
[Pages 51518-51528]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-24886]



[[Page 51517]]

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Part II





Environmental Protection Agency





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40 CFR Part 136



Guidelines Establishing Test Procedures for the Analysis of Pollutants; 
Measurement of Mercury in Water; Revisions to EPA Method 1631; Proposed 
Rule

  Federal Register / Vol. 66, No. 195 / Tuesday, October 9, 2001 / 
Proposed Rules  

[[Page 51518]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 136

[FRL-7074-6]


Guidelines Establishing Test Procedures for the Analysis of 
Pollutants; Measurement of Mercury in Water; Revisions to EPA Method 
1631; Proposed Rule

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: By this action, EPA is proposing modifications to EPA Method 
1631, Revision C: Mercury in Water by Oxidation, Purge and Trap, and 
Cold Vapor Atomic Fluorescence Spectrometry (Method 1631C), which 
measures mercury in aqueous samples. The proposed modifications would 
require use of certain ``clean techniques'' and quality control 
requirements when using this test method. The Agency is proposing to 
modify EPA Method 1631C to fulfill obligations under a Settlement 
Agreement designed to resolve litigation challenging an earlier EPA 
rulemaking that standardized this test method. The proposed 
modifications are intended to improve performance of EPA Method 1631C 
by reducing opportunities for contamination during sample collection 
and analysis. In addition, EPA is proposing revisions to this test 
method based on comments received from method users following method 
approval.

DATES: Comments must be postmarked, delivered by hand, or 
electronically mailed on or before December 10, 2001. Comments provided 
electronically will be considered timely if they are submitted 
electronically by 11:59 p.m. Eastern Standard Time (EST) on December 
10, 2001.

ADDRESSES: Mail written comments on the proposed rule to ``Method 
1631--Proposed Rule'' Comment Clerk (W-01-05), Water Docket (4101); 
U.S. Environmental Protection Agency; Ariel Rios Building; 1200 
Pennsylvania Avenue, NW., Washington, DC 20460. Hand deliveries should 
be delivered to: EPA's Water Docket at 401 M Street, SW., East Tower 
Basement (Room EB 57), Washington, DC 20460. If you wish to hand-
deliver your comments, please call (202) 260-3027 between 9:00 a.m. and 
4:00 p.m., Monday through Friday, excluding Federal holidays, to 
schedule an appointment. Comments also may be submitted electronically 
to: [email protected].

FOR FURTHER INFORMATION CONTACT: Maria Gomez-Taylor, Ph.D.; Engineering 
and Analysis Division (4303); 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) 260-
1639 or E-mail at [email protected].

SUPPLEMENTARY INFORMATION:

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, NPDES permitting authorities, 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'' (i.e., promulgated through rulemaking) standardized 
testing procedures for a given pollutant, the NPDES permitting 
authority must specify one of the approved testing procedures or an 
approved alternate test procedure for the measurements required under 
the permit. 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 
approved testing procedures. Categories and entities that may be 
regulated include:

------------------------------------------------------------------------
                                              Examples of  potentially
                 Category                        regulated  entities
------------------------------------------------------------------------
State, Territorial, and Indian Tribal       States, Territories, and
 Governments.                                Tribes authorized to
                                             administer the NPDES
                                             permitting program; States,
                                             Territories, and Tribes
                                             providing certification
                                             under Clean Water Act
                                             section 401.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not listed in the table could also be regulated. 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.

Record and Commenting Procedures

    The record for this rulemaking has been established under Docket 
Number W-01-05. A copy of the supporting documents cited in this 
proposal are available for review at EPA's Water Docket. The record is 
available for inspection from 9 a.m. to 4 p.m. EST, Monday through 
Friday, excluding Federal holidays at EPA's Water Docket, 401 M Street 
SW., East Tower Basement (Room EB 57), Washington, DC 20460. For access 
to docket materials, please call (202) 260-3027 to schedule an 
appointment.
    Commenters are requested to submit any references cited in their 
comments. Commenters also are requested to submit an original and three 
copies of their written comments and enclosures, and to clearly 
identify the specific issue(s) and method section(s) to which the 
comment applies. Commenters who want a confirmed receipt of their 
comments should include a self-addressed, stamped envelope. All 
comments must be postmarked or delivered by hand. No facsimiles (faxes) 
will be accepted.
    Electronic comments must be submitted as a Word Perfect for Windows 
5/6/7/8 file or an ASCII file, avoiding the use of special characters 
and any form of encryption. Comments and data also will be accepted on 
disks in Word Perfect 5/6/7/8 or ASCII file format. Electronic comments 
on this notice may be filed online at many Federal Depository 
Libraries. All electronic comments must be identified by docket number. 
Electronic comments will be transferred into a paper version for the 
official record. EPA will attempt to clarify electronic comments if 
there is an apparent error in transmission.

Information on Internet Access

    This Federal Register document has been placed on the Internet for 
public review and downloading at the following location: http//
www.epa.gov/fedrgstr. Method 1631, Revision C; Draft Method 1631, 
Revision D; the Method 1631 Guidance; and a Fact Sheet are available at 
www.epa.gov/ost/methods/1631.html or from the EPA Sample Control Center 
(SCC), DynCorp I&ET, 6101 Stevenson Ave., Alexandria, VA 22304 (703-
461-2100; [email protected]).

Outline of Notice

I. Statutory Authority
II. Background
    A. Regulatory Actions
    B. Settlement Agreement
III. Summary of Today's Action
IV. Proposed Revisions Based on the Settlement Agreement

[[Page 51519]]

    A. Additional Requirements for Clean Techniques and Quality 
Control Provisions
    B. Election by a Permittee/Industrial User
V. Proposed Additional Revisions to EPA Method 1631
    A. Use of Automated Flow-Injection Systems
    B. Blanks
    C. Calibration Over a Different Range
    D. Sample Preservation, Refrigeration, Headspace, Collection 
Containers, and Storage
    E. Shipment of Empty Sample Containers
    F. Scope of ``Should'' and ``May''
    G. Field Filtration for Dissolved Metals
    H. Carryover Test
    I. Correction of Part Numbers
    J. Use of Polyethylene or Polypropylene Vessels for Sample 
Digestion
    K. Indication of Complete Oxidation
    L. Adjustment for Amount of Bromine Monochloride to Blanks
    M. Addition of Method 1631 Guidance as a Reference
VI. Proposed Amendment to 40 CFR 136.3(e) Table II
VII. Administrative Requirements
    A. Executive Order 12866--Regulatory Planning and Review
    B. Regulatory Flexibility Act (RFA), as Amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 
U.S.C. 601 et seq.
    C. Unfunded Mandates Reform Act
    D. Paperwork Reduction Act
    E. National Technology Transfer and Advancement Act
    F. Executive Order 13045--Protection of Children from 
Environmental Health Risks and Safety Risks
    G. Executive Order 13132--Federalism
    H. Executive Order 13175--Consultation and Coordination with 
Indian Tribal Governments
    I. Executive Order 13211--Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. Plain Language Directive
VIII. Request for Comments

I. Statutory Authority

    Today's proposal is pursuant to the authority of sections 301, 
304(h), 307, and 501(a) of the Clean Water Act (CWA), 33 U.S.C. 1311, 
1314(h), 1317, 1361(a) (the ``Act''). Section 301 of the Act prohibits 
the discharge of any pollutant into navigable waters unless the 
discharge complies with a National Pollutant Discharge Elimination 
System (NPDES) permit, issued under section 402 of the Act. Section 
304(h) of the Act requires the Administrator of the EPA to ``promulgate 
guidelines establishing test procedures for the analysis of pollutants 
that shall include the factors which must be provided in any 
certification pursuant to section 401 of this Act or permit 
applications pursuant to section 402 of this Act.'' Section 501(a) of 
the Act authorizes the Administrator to ``prescribe such regulations as 
are necessary to carry out his function under this Act.'' EPA publishes 
CWA analytical method regulations at 40 CFR Part 136. The Administrator 
also has made these test procedures applicable to monitoring and 
reporting of NPDES permits (40 CFR Parts 122, Secs. 122.21, 122.41, 
122.44, and 123.25), and implementation of the pretreatment standards 
issued under section 307 of the Act (40 CFR Part 403, Secs. 403.10 and 
402.12).

II. Background

A. Regulatory Actions

    On May 26, 1998, EPA proposed Method 1631 at 40 CFR Part 136 for 
use in determining mercury at ambient water quality criteria levels in 
EPA's Clean Water Act programs (63 FR 28867). Subsequently, on March 5, 
1999, EPA published a Notice of Data Availability that included 
additional data supporting the application of Method 1631 to effluent 
matrices (64 FR 10596) in response to comments received at proposal. On 
June 8, 1999, EPA published a final rule promulgating EPA Method 1631, 
Revision B: Mercury in Water by Oxidation, Purge and Trap, and Cold 
Vapor Atomic Fluorescence Spectrometry (64 FR 30416) at 40 CFR Part 
136. EPA published a technical correction revising EPA Method 1631B to 
EPA Method 1631C (66 FR 32774; June 18, 2001) to clarify the method 
text regarding the use of field blanks (see Settlement Agreement 
discussion below).

B. Settlement Agreement

    In response to a petition for judicial review of EPA Method 1631B, 
EPA entered into negotiations with several industry groups. On October 
19, 2000, EPA entered into a Settlement Agreement with the Alliance of 
Automobile Manufacturers, Inc., the Chemical Manufacturers Association, 
and the Utility Water Act Group (collectively, Petitioners), and the 
American Forest & Paper Association (Intervenor). The Settlement 
Agreement (Alliance of Automobile Manufacturers, et al. v. EPA, No. 99-
1420, D.C. Dir.), is included in the rulemaking record in the Water 
Docket for today's proposal (see the ADDRESSES section of this proposal 
for details on the Water Docket). The Settlement Agreement includes 
four clauses that directly affect Method 1631 (Clauses 2, 3, 4, and 5).
    Clauses 2 and 3 of the Settlement Agreement committed EPA to sign a 
notice of final rulemaking by June 15, 2001, revising sections 12.4.2 
and 9.4.3.3 of Method 1631B to clarify the use of field blank 
subtraction (section 12.4.2) and the use of multiple field blanks 
(section 9.3.3.3) to determine whether test samples are acceptable for 
compliance monitoring purposes. EPA complied with that commitment, and 
on June 18, 2001, EPA published a final rule; technical correction 
notice (66 FR 32774) announcing a revised version of Method 1631 
(Revision C; Method 1631C). That notice included the technical 
corrections about field blanks required by the Settlement Agreement. At 
that time, no other changes were made to the test method.
    Clause 4 of the Settlement Agreement requires that EPA sign a 
notice for publication in the Federal Register on or before September 
30, 2001 to propose additional requirements for certain clean 
techniques and quality control (QC) provisions in Method 1631. Today's 
proposed rule complies with EPA's obligation under Clause 4 of the 
Settlement Agreement. The additional requirements were listed in the 
Settlement Agreement as Appendix A and are discussed in Section IV of 
this preamble. Clause 4 also requires that EPA propose that ``a 
National Pollutant Discharge Elimination System (NPDES) permittee or an 
industrial user of a publicly-owned treatment works (POTW) may elect 
not to implement such provisions in its discretion and at its peril, 
unless specifically provided otherwise by the relevant permitting 
agency or pretreatment control authority, as the case may be.''
    Clause 5 of the Settlement Agreement required that EPA publish a 
guidance document on or before March 1, 2001 specifying procedures for 
identifying, reducing, and demonstrating potential matrix 
interferences. On February 27, 2001, EPA published Guidance for 
Implementation and Use of EPA Method 1631 for the Determination of Low-
Level Mercury (40 CFR Part 136) (EPA 821-R-01-023; March 2001) to 
address this clause and to assist regulatory agencies, dischargers, 
industrial users, and laboratories in the application of Method 1631 to 
ambient water and wastewater. In addition to providing information on 
potential matrix interferences, the guidance provides information on 
the use of clean techniques and method flexibility, and answers 
frequently asked questions regarding method implementation.

III. Summary of Today's Action

    This rulemaking proposes to modify EPA Method 1631 to require the 
use of certain clean techniques and quality control (QC) provisions in 
accordance with clause 4 of the Settlement Agreement. These changes are 
in response to the petitioners' concerns

[[Page 51520]]

that results produced by laboratories using EPA Method 1631 would not 
be reliable unless the optional clean techniques and QC provisions are 
required. These revisions are discussed in Section IV of this proposal 
and are included in draft Method 1631, Revision D (Method 1631D).
    Today's notice also proposes improvements and clarifications to EPA 
Method 1631 to make this test method more consistent with other 
approved methods and current practices, and easier to use. These 
proposed revisions are based on comments received from method users 
since promulgation of Method 1631. The proposed revisions are discussed 
in Section V and are included in draft Method 1631D.

IV. Proposed Revisions Based on the Settlement Agreement

A. Additional Requirements for Clean Techniques and Quality Control 
Provisions

    Clause 4 of the Settlement Agreement requires EPA to sign a notice 
for publication in the Federal Register on or before September 30, 
2001, proposing to require certain clean techniques and quality control 
(QC) provisions in EPA Method 1631. These requirements to propose clean 
techniques and QC provisions are listed in Appendix A to the Settlement 
Agreement and are reproduced below. The Petitioners believe that these 
additional requirements are necessary to prevent samples from becoming 
contaminated during the sampling and analysis process. EPA believes 
that these techniques may improve test performance. EPA refers readers 
to the appropriate section of draft EPA Method 1631, Revision D for the 
proposed revised language, which is indicated in the draft revised 
method in brackets and italics.
    EPA solicits your comments and/or data on the proposed 
requirements, collectively or individually, and requests that you 
provide a reason to support your position.
1. Proposed Revision to Section 1.4
    Item 1 of Appendix A to the Settlement Agreement states, ``Section 
1.4 currently explains the importance of minimizing contamination of 
ambient water samples and explains that the Method includes suggestions 
for improvements to minimize contamination and maximize the ability of 
laboratories to make reliable measurements. The notice shall invite 
comment on revisions to this section to explain that certain sections 
contain suggestions and that other sections contain requirements to 
minimize contamination.'' Revision D, as proposed, includes a statement 
to that effect in Section 1.4.
2. Proposed Revision to Sections 2.3 and 8.5
    Item 2 of Appendix A to the Settlement Agreement states, ``Sections 
2.3 and 8.5 currently suggest that a sample used for the determination 
of methyl mercury should be preserved with 5 mL/L HCl solution only. 
The notice would invite comment on whether to change these sections to 
require the use of HCl for preservation if the sample is collected for 
the determination of methyl mercury.'' Revision D, as proposed, 
includes statements in Sections 2.3 and 8.5 corresponding to this 
requirement.
3. Proposed Revision to Section 4.3.3
    Item 3 of Appendix A to the Settlement Agreement states, ``Section 
4.3.3 currently suggests the use of a clean room or a clean bench. The 
notice would invite comment on whether to change this section to 
require a clean bench if a clean room is not available. The notice 
would not invite comment on whether to require a nonmetal hood because 
the Agency believes removal and replacement of existing metal hoods is 
unnecessary; use of a plastic awning in the hood prevents contamination 
during sample digestion.'' Revision D, as proposed, reflects this 
language in Section 4.3.3.
4. Proposed Revision to Section 4.3.4
    Item 4 of Appendix A to the Settlement Agreement states, ``Section 
4.3.4 currently suggests precautions to minimize exposure of the 
apparatus to contamination. The notice would invite comment on whether 
to change the `shoulds' to `musts.' '' Revision D, as proposed, changes 
the `shoulds' to `musts' in Section 4.3.4.
5. Proposed Revision to Section 4.3.5
    Item 5 of Appendix A to the Settlement Agreement states, ``Section 
4.3.5 currently recommends cleaning work surfaces before a batch of 
samples is processed. The notice would invite comment on whether to 
require the laboratory to clean work surfaces after processing a batch 
of samples with high levels of mercury.'' Revision D, as proposed, 
includes a requirement to this effect in Section 4.3.5.
6. Proposed Revision to Section 4.3.7.1
    Item 6 of Appendix A to the Settlement Agreement states, ``Section 
4.3.7.1 currently recommends that only fluoropolymer or borosilicate 
glass containers be used for samples. The notice would invite comment 
on whether to change `should' to `must' to respond to Petitioners' 
concern.'' Revision D, as proposed, changes the `should' to `must' in 
Section 4.3.7.1.
7. Proposed Revision to Sections 4.3.8.1 and 11.2.4
    Item 7 of Appendix A to the Settlement Agreement states, ``Sections 
4.3.8.1 and 11.2.4 currently suggest that a bubbler blank be used to 
check for carryover after encountering an unusually concentrated 
sample. The notice would invite comment on whether to change `should' 
to `must' in both sections to require analysis of the bubbler blank.'' 
Revision D, as proposed, changes the `should' to `must' in Section 
4.3.8.1 and also changes Section 11.2 to correspond to this 
requirement.
8. Proposed Revision to Section 4.3.8.4
    Item 8 of Appendix A to the Settlement Agreement states, ``Section 
4.3.8.4 currently suggests that sample processing should occur as far 
as possible from sources of airborne contamination. The notice would 
invite comment on whether to change the `should' to `must.''' Revision 
D, as proposed, changes the `should' to `must' in Section 4.3.8.4.
9. Proposed Revision to Section 4.4.3
    Item 9 of Appendix A to the Settlement Agreement states ``Section 
4.4.3 currently explains a concern regarding condensation of water in 
the gold traps. The section explains that condensation can be avoided 
by predrying the gold trap, and by discarding those traps that tend to 
absorb large quantities of water vapor. The notice would invite comment 
on whether to change this Section to preclude the use of gold traps 
that tend to absorb large quantities of water vapor.'' Revision D, as 
proposed, changes Section 4.4.3 to include a requirement to this 
effect.
10. Proposed Revision to Sections 6.1.2.3 and 9.4.4.1
    Item 10 of Appendix A to the Settlement Agreement states, 
``Sections 6.1.2.3 and 9.4.4.1 currently recommend the analysis of 
bottle blanks. The notice would invite comment on whether to change 
`should' to `must' to require analysis of bottle blanks in these 
sections.'' Revision D, as proposed, changes the `should' to `must' in 
Section 6.1.2.3 and also changes Section 9.4.7 to correspond to this 
requirement because the requirements for bottle blanks are presented in 
this section.

[[Page 51521]]

11. Proposed Revision to Section 7.2
    Item 11 of Appendix A to the Settlement Agreement states, ``Section 
7.2 currently lists two ways to assure that laboratory air is low in 
both particulate and gaseous mercury: use of outside air that is very 
low in mercury and use of inside air recycled through a gold-coated 
filter. As presently written, outside air `should' be brought into the 
class-100 clean bench air intake. The notice would invite comment on 
whether to change this `should' in the outdoor air option to a 
`must.''' Revision D, as proposed, changes the `should' to `must' in 
Section 7.2.
12. Proposed Revision to Section 8.5.3
    Item 12 of Appendix A to the Settlement Agreement states, ``Section 
8.5.3 currently requires handling of samples in a mercury-free clean 
bench. The notice would invite comment on whether to change `should' to 
`must.''' Revision D, as proposed, changes the `should' to `must' in 
Section 8.5.3.
13. Proposed Revision to Note at Section 8.5.3
    Item 13 of Appendix A to the Settlement Agreement states ``Section 
8.5.3 (note) currently states that samples `should' be filtered and 
preserved in accordance with the procedures in Method 1669. The notice 
would invite comment on whether to change the `should' to `must' but 
only for the provisions of Method 1669 related to filtration and 
preservation of samples when circumstances prevent overnight sample 
shipment (i.e., sections 2.9 and 2.10 of EPA Method 1669).'' Revision 
D, as proposed, changes the `should' to `must' in the Section 8.5.3 
note.
14. Proposed Revision to Section 8.6
    Item 14 of Appendix A to the Settlement Agreement states, ``Section 
8.6 currently suggests that sample bottles should be stored in clean 
(new) polyethylene bags until sample analysis. The notice would invite 
comment on whether to change this section to require storage in clean 
bags by changing `should' to `must.''' Revision D, as proposed, changes 
the `should' to `must' in Section 8.6.
15. Proposed Revision to Section 9.4.4.2
    Item 15 of Appendix A to the Settlement Agreement states, ``Section 
9.4.4.2 currently suggests the use of `Clean Hands/Dirty Hands' when 
preparing sampler check blanks at the laboratory or cleaning facility. 
The notice would invite comment on whether to change `should' to `must' 
in this section for low-level mercury measurements.'' Revision D, as 
proposed, makes this change in Section 9.4.6.1 because the ``clean 
hands/dirty hands'' technique is referenced in that section.
16. Proposed Revision to Section 11.1.2
    Item 16 of Appendix A to the Settlement Agreement states, ``Section 
11.1.2 currently suggests that there should be 2 matrix spike/matrix 
spike duplicate pairs for each analytical batch of 20 samples. The 
notice would invite comment on whether to make the matrix spike/matrix 
spike duplicate pairs mandatory by changing `should' to `must be a 
minimum of' in this section.'' Revision D, as proposed, makes this 
change in Section 11.1.2.

B. Election by a Permittee/Industrial User

    In EPA's ``Guidance for the Implementation and Use of EPA Method 
1631 for the Determination of Low Level Mercury (40 CFR Part 136),'' 
dated March 2001, EPA recommends that State and Federal agencies 
measuring ambient water quality for compliance with water quality 
standards at very low concentrations should require, as a matter of 
internal agency protocol, that their personnel use clean techniques. 
EPA also suggests in this guidance, that NPDES permits specify the use 
of clean techniques, on a permit-by-permit basis, depending on the 
measurement level of concern, upon request by the permit applicant. The 
guidance also states that EPA will propose additional requirements for 
clean techniques by October 2001, and that EPA may revise the guidance 
in accordance with any requirements that are promulgated as a result.
    Clause 4 of the Settlement Agreement requires EPA to propose that 
an NPDES permittee or an industrial user of a POTW may elect not to 
implement the clean techniques and QC provisions that are listed in 
Appendix A to the Settlement Agreement and that are proposed today ``in 
its discretion and at its peril, unless specifically provided otherwise 
by the relevant permitting agency or pretreatment control authority, as 
the case may be.'' Revision D, as proposed, includes this election in 
Section 1.13.
    As required by the Settlement Agreement, the election is applicable 
to the clean techniques and QC provisions designated in Appendix A to 
the Settlement Agreement only. These provisions are discussed in 
Section IV.A of this notice and are designated throughout draft EPA 
Method 1631D by bracketed and italicized text. If Section 1.13 is 
promulgated as proposed, any text pertaining to clean techniques and 
quality control provisions that is also promulgated as proposed under 
the Settlement Agreement, would remain italicized and bracketed in the 
approved version of EPA Method 1631D to designate the techniques and 
provisions to which the election is applicable.
    Users of EPA Method 1631 should be aware that the election in 
Clause 4 of the Settlement Agreement would apply to the permittee/
industrial user only, and not to a regulatory/control authority or to 
other users of the Method. Regulatory/control authorities and other 
users of EPA Method 1631 would be required to use the clean techniques 
and QC provisions as designated by the italicized bracketed text in the 
affected sections of EPA Method 1631D. Permittees/industrial users 
should be aware of the potential disparity that could result if a 
sample is analyzed by a permittee/industrial user not using the clean 
techniques and QC provisions and also by a regulatory/control authority 
using the clean techniques and QC provisions. In addition, if a 
regulatory/control authority requires that a permittee/industrial user 
use the clean techniques and QC provisions, the burden would be on the 
regulatory/control authority to incorporate this requirement into 
regulations or permits.
    EPA is soliciting comments on this election and on the specific 
techniques and provisions to which the election would be applicable. 
EPA is soliciting comments particularly from permittees/industrial 
users because the users would have the election, and from regulatory/
control authorities and other users of EPA Method 1631 because they 
would not. EPA also seeks comment on whether the philosophical change 
embodied by the election (i.e., to allow a permittee/industrial user to 
not use certain techniques and QC provisions of an analytical method, 
yet require regulatory/control authorities and other users to use these 
techniques) is desirable, in general. In addition, EPA solicits 
comments on alternatives to the Settlement Agreement approach, mainly 
on whether the additional clean techniques and QC requirements should 
be applicable to all users or whether the additional requirements 
should be optional for all users.

V. Proposed Additional Revisions to EPA Method 1631

    Since promulgation of EPA Method 1631 in June 1999, EPA has 
received many suggestions for method improvement and requests to 
clarify certain method procedures. In today's action, EPA is proposing 
revisions to clarify and improve the method in

[[Page 51522]]

response to these comments. This section explains the revisions 
included in draft EPA Method 1631D in response to these comments. EPA 
is soliciting comment on the proposed revisions described below.

A. Use of Automated Flow-Injection Systems

    Automated flow-injection systems are currently available and have 
been used successfully for performing EPA Method 1631 procedures for 
several years. These systems use flow injection and a gas-liquid 
separator in place of the bubbler.
    EPA has worked with several users of these systems to develop 
appropriate calibration and calculation procedures and blank sample 
requirements and has included these procedures and requirements in 
draft Method 1631D. The revisions incorporate calibration blanks 
(Section 9.4.2), calibration procedures (Section 10.2), and result 
calculation procedures (Section 2.2) that are specific for flow 
injection systems. The proposed method also refers to flow injection 
systems throughout the text, and includes a figure depicting the flow-
injection system (Figure 3). The revisions will expand the use of the 
Method by providing appropriate procedures for the use of automated 
flow injection systems.

B. Blanks

    EPA Method 1631C includes the use of bubbler blanks (Section 
9.4.1), reagent blanks (Section 9.4.2), field blanks (Section 9.4.3), 
equipment blanks (Section 9.4.4), bottle blanks (Section 9.4.4.1), and 
sampler check blanks (Section 9.4.4.1). Several commenters noted that 
the blanks are not well defined and that blank requirements are 
inconsistent with common usage. In addition, commenters noted that the 
types and requirements for blanks are not appropriate for use with the 
flow-injection systems. To address these comments, EPA added 
definitions for all blanks in the Glossary of draft Method 1631D, and 
clarified these definitions throughout the Method text. EPA has also 
added requirements for calibration blanks (for use with flow injection 
systems only) and method blanks (for use with both bubbler and flow 
injection systems). The proposed revisions are discussed in the 
following sections.
1. Definitions
    In response to several comments that the types of blank samples 
required by Method 1631 are defined inconsistently throughout the 
Method, EPA revised Section 17 of draft Method 1631D to include 
definitions for the calibration blank, method blank, reagent blank, 
field blank, and bottle blank samples. Section 17 of draft Method 1631D 
also includes a revised definition of the bubbler blank to clarify its 
specificity for use with bubbler systems. In addition, EPA revised 
Section 9.4 in draft Method 1631D to further clarify definitions and 
use of blank samples for both bubbler and flow-injection systems.
    The proposed revisions address more accurately EPA's intent to 
allow the use of both bubbler and flow injection systems for 
determination of mercury using Method 1631. The revisions also clarify 
the application and use of blank samples to identify and handle 
potential contamination.
2. Calibration Blanks
    In EPA Method 1631, bubbler blanks are used to establish a 
background for the bubbler system (i.e., bubbler, traps, and cold-vapor 
atomic fluorescence detector) and can be used to identify potential 
carryover from one sample to the succeeding sample (see Section 9.4.1 
of EPA Method 1631C). Results of bubbler blanks are subtracted from all 
raw calibration and sample results. Bubbler blanks, however, are not 
appropriate for flow injection systems. Hence, EPA added a requirement 
for calibration blanks, when using a flow injection system. The 
performance criteria and application requirements of the calibration 
blanks are identical to those for the bubbler blanks.
3. Method and Reagent Blanks
    EPA Method 1631 requires reagent blanks to identify contamination 
from reagents, but these blanks are required only when a new batch of 
reagents is prepared, with verification in triplicate each month, and 
are not required with each analytical batch (see Section 9.4.2 of EPA 
Method 1631C). Method 1631 also requires field blanks to identify 
contamination from sample collection and transport (see Section 9.4.3 
of EPA Method 1631C). These field blanks may be used to identify 
contamination introduced at some point during the entire measurement 
process from sample collection through mercury detection, but cannot 
isolate contamination caused by sample collection and transport from 
contamination that is introduced during sample processing and analysis.
    Several method users commented that laboratories typically use 
method blanks to determine potential contamination in the analytical 
system during sample preparation and analysis. These method blanks are 
prepared and analyzed using procedures identical to those used to 
prepare and analyze the corresponding samples.
    Because method blanks can be used to identify total analytical 
system contamination, and are subjected to all sample processing and 
analytical steps including digestion, reduction, and determination, EPA 
added a requirement for method blanks to draft Method 1631D. The 
proposed method includes a requirement that at least three method 
blanks be analyzed with each analytical batch. It also includes a 
requirement that any sample requiring increased oxidation (e.g., an 
increased amount of reagent) be associated with at least one method 
blank that is processed and analyzed using the same amount of increased 
oxidation. The performance criteria for the method blanks is identical 
to the field blank criteria. This requirement provides method users 
with a more appropriate procedure for addressing contamination that may 
result during the entire analytical procedure.
    EPA also proposes to revise the requirement for the frequency of 
reagent blanks. In draft Method 1631D, analysis of reagent blanks is 
required only when each new batch of reagents is prepared. EPA believes 
that the requirements for method blanks included in draft Method 1631D 
will be sufficient to identify contamination that may be introduced by 
reagent solutions during processing and analysis of an analytical 
batch.
4. Equipment and Bottle Blanks
    EPA received several comments on Method 1631 expressing confusion 
over the use of the terms ``equipment blank,'' ``sampler check blank,'' 
and ``bottle blank.'' Commenters also noted that the terms ``equipment 
blank'' and ``sampler check'' blank are synonymous and that using two 
terms to identify blanks used to check sample collection equipment is 
confusing. Additionally, commenters were concerned that bottle blanks 
are listed in EPA Method 1631 under blanks specific for determination 
of contamination in sample collection equipment. These commenters noted 
that bottle blanks also are necessary to determine contamination in 
bottles used for sample preparation and analysis, and recommended that 
bottle blanks be analyzed at a frequency of at least 20 percent of each 
lot used.
    In response to these comments, EPA proposes to change the term 
``sampler check blank'' to ``equipment blank'' in Section 9.4.6 of 
draft Method 1631D, and to revise Section 9.4 of the method to expand 
the application of bottle blanks for determination of contamination in 
bottles used for both sample collection and analysis (Section

[[Page 51523]]

9.4.7). EPA also included a requirement in draft Method 1631D that a 
minimum of 20 percent of the bottles from a given lot shall be tested 
and demonstrated to be free of mercury at the Method MDL (Section 
6.1.2.4).

C. Calibration Over a Different Range

    Several users of Method 1631 stated that they prefer to use EPA 
Method 1631 for mercury determination because it is less prone to 
interferences than other available methods, and would like to apply EPA 
Method 1631 procedures across a higher calibration range. Other users 
of the method commented that when they are analyzing samples known to 
be within a narrower range of concentrations than that of the current 
method (e.g., an analytical run consisting of ambient samples), they 
prefer to calibrate the analytical system across the narrower range. 
Additional users noted that they desire to calibrate to a lower point 
to measure mercury in blanks to a lower level.
    In response to these comments and to allow expanded use of EPA 
Method 1631, EPA included a provision in draft Method 1631D to allow 
calibration over ranges other than the range currently specified 
(Section 10.4). EPA included certain criteria with this provision to 
ensure that this allowance does not compromise data quality. These 
criteria are: (1) there must be a minimum of five, non-zero calibration 
points; (2) the difference between successive calibration points must 
be no greater than a factor of 10 and no less than a factor of 2 and 
should be approximately evenly spaced on a logarithmic scale over the 
calibration range; (3) the relative standard deviation (RSD) of the 
calibration factors for all calibration points must be less than 15%; 
(4) the calibration factor for any calibration point at a concentration 
greater than 100 ng/L must be within plus or minus 15% of the average 
calibration factor for the points at or below 100 ng/L; (5) the 
calibration factor for any point less than 5 ng/L must be within plus 
or minus 25% of the average calibration factor for all points; (6) if 
the highest calibration point is increased above 100 ng/L, the lowest 
calibration point (ML) must be increased commensurately above 0.5 ng/L; 
and, (7) if the calibration is to a higher range and this Method is 
used for regulatory compliance, the ML must be less than one-third the 
regulatory compliance limit.

D. Sample Preservation, Refrigeration, Headspace, Collection 
Containers, and Storage

    Section 8.5 of the currently approved EPA Method 1631 requires that 
samples are preserved upon collection, or alternatively, are collected 
only in fluoropolymer bottles, with zero headspace, capped tightly, and 
stored at 0-4 deg.C until they can be preserved within 48 hours of 
collection.
    Since promulgation of EPA Method 1631, EPA has received numerous 
comments on the sample preservation, refrigeration, headspace, and 
holding time requirements in the method and in Table II at 40 CFR 
136.3(e). EPA has considered these comments and has included revisions 
in today's draft Method 1631D to address the recommendations from 
method users. Specific proposed revisions regarding preservation, 
refrigeration, container type, headspace, and holding time requirements 
are discussed below. The proposed changes are based on the comments 
received from method users and EPA requests data to support whether the 
changes would affect the quality of results. EPA is not proposing to 
revise the requirements that samples collected for determination of 
total mercury must be capped tightly and must be preserved or analyzed 
within 48 hours of collection. EPA is requesting comment on whether 
this requirement should be kept.
1. Sample Preservation
    Sections 2.3 and 8.5 of EPA Method 1631 currently require that 
samples are either preserved with hydrochloric acid (HCl) or bromine 
monochloride (BrCl) solution immediately upon collection, or 
alternatively, are collected and stored under specific conditions 
(i.e., zero headspace, fluoropolymer bottles, capped tightly, and 
stored at 0-4 deg.C) until they can be preserved in the laboratory 
within 48 hours of collection. As discussed in Section IV.A.2, EPA is 
also proposing to revise the sample preservation requirement in 
Sections 2.3 and 8.5 of the method for the determination of methyl 
mercury.
    Commenters claim there is no need to preserve samples for total Hg 
if BrCl is added to the sample in the laboratory and the sample is 
allowed to stand for a minimum of 24 hours to oxidize all forms and 
species of mercury to Hg(II). Commenters also noted that the 
immediate preservation of samples collected for total or dissolved 
mercury determination is unnecessary, provided the samples are 
preserved or analyzed within 48 hours of collection, and have requested 
elimination of the requirement for preservation so that solutions of 
HCl or BrCl do not need to be shipped to the sampling site.
    EPA currently is reviewing data that indicate that unpreserved 
samples collected for measurement of low level mercury may be stable 
for as long as 35 days. Additionally, EPA does not have data 
demonstrating that results of samples for total or dissolved mercury 
that are not preserved immediately are compromised, and solicits such 
data to determine whether immediate preservation should be required. 
Therefore, EPA has included revisions in draft Method 1631D (Section 
8.5) to eliminate the requirement for immediate preservation of samples 
collected for determination of mercury using EPA Method 1631. Today's 
proposed method does not include a revision to the requirement for 
immediate preservation of samples collected for methyl- and di-methyl 
mercury determination.
    EPA is also proposing to amend Table II of 40 CFR 136.3(e) to 
include requirements for preservation of samples collected for mercury 
measurement using Method 1631 within 48 hours of sample collection, 
using BrCl or HCl (see Section VI of this notice).
2. Sample Refrigeration
    Users of EPA Method 1631 claim that there is no need to refrigerate 
unpreserved samples for total or dissolved mercury because the bromine 
monochloride (BrCl) digestion converts all forms of Hg to 
Hg(II). Therefore, if a given form or species of Hg were 
converted to another form or species in the absence of refrigeration 
(e.g., through biological activity), the BrCl digestion would convert 
the new form, as well as any remaining portion of the old form, to 
Hg(II). Commenters have requested that EPA eliminate the 
requirement for refrigeration of unpreserved samples because of costs 
and logistics problems (i.e., refrigeration requires purchase of ice, 
shipment of the sample in a cooler, and testing of the sample at the 
laboratory to make certain that the temperature remains in the range 
specified, 0-4  deg.C).
    EPA currently does not have data demonstrating that refrigeration 
of unpreserved samples for measurement of total or dissolved mercury 
using Method 1631 is necessary, and is seeking such data to determine 
if refrigeration should be required. In the absence of data, EPA has 
revised draft Method 1631D (Section 8.5) to eliminate the requirement 
for refrigeration of unpreserved samples, provided that the sample is 
tightly capped and is either preserved or analyzed within 48 hours of 
collection.
    EPA also has received comments that samples collected for 
measurement of mercury using Method 1631 are stable for up to 30 days 
prior to either preservation or analysis. EPA is

[[Page 51524]]

requesting data to support this comment. EPA will consider submitted 
data, and if appropriate, will re-evaluate the requirement for 
preservation or analysis of samples within 48 hours.
3. Sample Headspace
    Section 8.5 of EPA Method 1631 requires that mercury samples are 
collected with zero headspace if they are not preserved immediately. A 
laboratory involved in the development of EPA Method 1631 commented 
that, although it is necessary to collect samples for methyl- and 
dimethyl-mercury with zero headspace, it is not necessary to collect 
samples for total or dissolved mercury with zero headspace. For total 
or dissolved mercury, the partitioning of volatile forms of mercury 
into a relatively small headspace volume is negligible.
    EPA has removed the requirement for collecting unpreserved samples 
with zero headspace in draft Method 1631D (Section 8.5.1), provided the 
sample is tightly capped and is preserved or analyzed within 48 hours 
of sample collection. The proposed method does not include a revision 
of the requirement to collect samples for methyl mercury with no 
headspace.
4. Sample Collection Containers
    Section 8.5.1 of EPA Method 1631 requires that unpreserved samples 
must be collected in fluoropolymer sample containers. Several users of 
EPA Method 1631 have commented that, in addition to fluoropolymer 
bottles, glass bottles can be used successfully for collection of 
unpreserved samples, provided the containers are demonstrated to be 
clean, are tightly capped, and are preserved or analyzed within 48 
hours of sample collection.
    EPA is soliciting data demonstrating that the use of glass 
containers for collection of mercury samples that are not preserved 
immediately does not compromise the quality of results obtained using 
EPA Method 1631. EPA has revised Sections 2.1, 4.3.7.1, and 8.5.1 in 
draft Method 1631D, to allow collection of unpreserved samples in 
either clean fluoropolymer or clean glass sample containers.
    As discussed previously in Section V.D.1 of this document, EPA is 
requesting data to support the comment that samples collected for 
measurement of mercury using Method 1631 are stable for up to 30 days 
prior to preservation or analysis. EPA will consider submitted data, 
and if appropriate, will re-evaluate the requirement for preservation 
or analysis of samples within 48 hours.
5. Holding Time
    Section 8.5 of EPA Method 1631 states that acid- and BrCl-preserved 
samples are stable for a period of 28 days. Several laboratories that 
assisted in the development of EPA Method 1631 believe that samples are 
stable for at least three months and have provided data to EPA 
demonstrating this stability in mercury samples that have been 
preserved with either BrCl or HCl. These data are included in the 
Record supporting today's rule.
    EPA revised Section 8.5 of draft Method 1631D to recognize that 
acid- or BrCl-preserved samples that are collected for measuring 
mercury using Method 1631 are stable for a period of 90 days. EPA is 
also proposing to amend Table II of 40 CFR 136.3(e) to include a 
maximum holding time of 90 days for samples collected for determination 
of mercury using Method 1631 (see Section VI of this preamble).

E. Shipment of Empty Sample Containers

    Section 6.1.2.1 of EPA Method 1631 requires that sample bottles be 
filled with 0.4% HCl solution and stored until use. EPA Method 1631 
also references Section 6.3.1 of EPA Method 1669, which suggests that 
clean sample bottles should be filled with reagent water for shipment 
to the sampling site prior to sample collection.
    Commenters have stated that EPA Methods 1631 and 1669 should allow 
shipment of empty sample bottles to avoid shipping acid and to save 
shipping weight. As with sample refrigeration and preservation, EPA is 
soliciting data demonstrating whether shipping sample bottles full of 
dilute acid or reagent water is necessary and should be required. We 
have revised Section 6.1.2.1 in draft Method 1631D to allow shipment of 
empty bottles for sample collection based on comments from method 
users.

F. Scope of ``Should'' and ``May''

    The introduction to EPA Method 1631 contains a note that addresses 
the performance-based aspects of the Method. The note states that the 
terms ``shall'' and ``must'' define procedures required for producing 
reliable data at water quality criteria levels and that the terms 
``should'' and ``may'' indicate optional steps that may be modified or 
omitted if the laboratory can demonstrate that the modified method 
produces results equivalent or superior to results produced by the 
unmodified method. As discussed in Section IV of today's notice, EPA is 
proposing additional requirements for clean techniques and quality 
control that would, if implemented, change certain ``should'' and 
``may'' to ``shall'' and ``must.''
    Some commenters have interpreted the terms ``should'' and ``may'' 
as limiting the applicability of the performance-based allowances in 
the Method. EPA does not intend this restriction. As stated in Sections 
1.8 and 9 of EPA Method 1631, any procedure may be modified, except for 
procedures required as defined by the terms ``shall'' and ``must'' and 
all QC tests.
    To preclude ambiguity, EPA has revised the note in draft Method 
1631D to clarify that the laboratory is permitted to omit steps or 
modify procedures provided that all performance requirements in this 
Method are met, but that the laboratory must not omit or modify any 
procedure defined by the term ``shall'' or ``must'' and must perform 
all quality control tests.

G. Field Filtration for Dissolved Metals

    Both EPA Method 1669 (Section 8.3) and the current version of EPA 
Method 1631 (Method 1631C, Section 8.5.3) recommend that filtration of 
samples collected for dissolved Hg should be performed in the clean 
room of the laboratory. In contrast, 40 CFR 136.3(e), Table II, 
footnote 7, says that samples for dissolved metals should be filtered 
immediately on-site before adding preservative.
    Since promulgation of EPA Method 1631, some commenters have noted 
that it is preferable to filter samples for dissolved Hg in the 
laboratory under controlled clean conditions. Other commenters, 
however, have noted that it is preferable to filter samples for 
dissolved Hg immediately upon collection, thereby allowing for in-line 
filtration and immediate preservation if desired.
    EPA believes that filtration of mercury samples in either the field 
or laboratory is appropriate, provided the filtration is performed in a 
clean area, and provided that samples are accompanied by a blank that 
has been filtered under the same conditions. EPA has revised Sections 
2.2 and 8.4 of draft Method 1631D to allow for both in-field and 
laboratory sample filtration under these provisions.
    EPA is also proposing to amend 40 CFR 136.3(e) Table II to include 
requirements for filtration of samples for measurement of dissolved 
mercury using Method 1631, in a clean area in the laboratory or in the 
field (see Section VI of this preamble for proposed revisions to 40 CFR 
136.3(e), Table II).

[[Page 51525]]

H. Carryover Test

    The bubbler blank carryover test in EPA Method 1631 is recommended 
``when an unusually concentrated sample is encountered'' (Method 1631C, 
Section 4.3.8.1) or ``after very high samples'' (Method 1631C, Section 
11.2.4).
    Several commenters stated that ``unusually concentrated'' and 
``high sample'' are not defined. Commenters also have noted that it may 
not be practical to stop a run and analyze a bubbler blank immediately 
after these samples. Often a sample is determined to have a high Hg 
concentration that could result in carryover only after subsequent 
samples have been analyzed or at the completion of an analytical batch.
    To quantify the concentration of mercury in a sample that would 
carry a concentration into a subsequent sample, EPA has included a 
carryover test in draft Method 1631D (Section 4.3.8.1) that is similar 
to that in Section 8.5.1 of EPA Method 1624B for analysis of volatile 
organic compounds using a gas chromatograph/mass spectrometer (40 CFR 
Part 136, appendix A). In this test, successively greater 
concentrations of mercury in reagent water are analyzed to determine 
the concentration at which more than 0.2 ng/L (the MDL in Method 1631) 
would be measured in a subsequent bubbler blank.
    EPA also has included revisions in draft Method 1631D (Section 
4.3.8.1 and Section 11.2.1.3) to require that when an unusually 
concentrated sample is encountered, a bubbler blank must be analyzed to 
check for carryover and that samples run immediately following a sample 
that has been determined to result in carryover must be reanalyzed 
using a bubbler that is demonstrated to be free of Hg at the 0.2 ng/L 
level.

I. Correction of Part Numbers

    Users of Method 1631 have informed EPA that the supplier does not 
recognize part numbers for the peristaltic pump or tubing suggested in 
the method. The supplier has informed us that the leading letter in the 
part number signifies the version of the catalog and should be omitted 
from the part number. EPA has corrected these part numbers in proposed 
Method 1631D (Sections 6.1.3.2 and 6.1.3.3).

J. Use of Polyethylene or Polypropylene Vessels for Sample Digestion

    Most methods for determination of metals allow polyethylene bottles 
as sample containers (see 40 CFR Part 136, Table II, footnote 1). EPA 
Method 1631 requires use of glass or fluoropolymer because mercury can 
diffuse in and out of polyethylene bottles (see Section 16.4 of EPA 
Method 1631).
    Commenters have stated that, although fluoropolymer or glass 
bottles are necessary for sample collection, this type of labware is 
not necessary for sample digestion and other laboratory uses, because 
mercury will not diffuse through these materials in the relatively 
short time during which the sample is analyzed. Because polyethylene 
and polypropylene is less expensive than fluoropolymer and is less 
susceptible to breakage than glass, EPA has included a revision to this 
requirement in draft Method 1631D (Section 4.3.7.1) to allow use of 
polyethylene or polypropylene labware for sample digestion and 
preparation, but not for sample collection.

K. Indication of Complete Oxidation

    Section 8.1 of EPA Method 1631 currently states that the pH of all 
aqueous samples must be tested immediately before analysis to ensure 
that the sample has been properly preserved.
    Users of EPA Method 1631 have noted that the pH of a sample 
provides an insufficient indication of whether or not the sample is 
completely oxidized or ready for analysis, and cite as an example, 
samples containing high concentrations of sulfides or other reducing 
compounds that can consume BrCl, but still have a pH less than 2. These 
commenters have stated that color is a better indication of complete 
oxidation (see Sections 11.1.1.1 and 11.1.1.2 of EPA Method 1631).
    EPA proposes to revise Section 8.1 in EPA Method 1631D to recognize 
that samples must be completely oxidized prior to direct analysis and 
that pH alone is not sufficient for determination of complete 
oxidation.

L. Adjustment for Amount of Bromine Monochloride to Blanks

    Section 9.4.2.2 of EPA Method 1631 currently requires that the 
amount of reagent that is added to a reagent blank must be the same as 
the amount of reagent that is added to the samples. One of the 
laboratories responsible for the development of EPA Method 1631 
commented that this requirement is inconsistent with Section 12.3 which 
allows adjustment during calculation of reagent blanks for greater 
amounts of reagent that may be added to samples requiring increased 
oxidation. Users also have commented that, although the correction 
allowed in Section 12.3 is appropriate for volume adjustment, it is not 
necessarily appropriate for adjustment of increased reagent 
concentration.
    In draft Method 1631D, EPA has clarified that a sample requiring 
increased oxidation via an increased amount of reagents must be 
associated with at least one blank sample that has been analyzed using 
procedures identical to those used to prepare and analyze the sample. 
This requirement is included with the requirements for method blanks 
(draft Method 1631D, Section 9.4.4.3).

M. Addition of Method 1631 Guidance as a Reference

    On March 2001, EPA published guidance to assist users with the 
implementation and use of EPA Method 1631. This guidance, Guidance for 
Implementation and Use of EPA Method 1631 for the Determination of Low-
Level Mercury (40 CFR Part 136) (EPA 821-R-01-023, March 2001), was 
developed and published largely in response to the October 19, 2000 
Settlement Agreement. EPA has added a reference for this guidance to 
draft Method 1631D (Section 16.22).

VI. Proposed Amendment to 40 CFR 136.3(e) Table II

    EPA is today proposing to amend Table II at 40 CFR 136.3(e), which 
lists required containers, preservation techniques, and maximum holding 
times for biological and chemical parameters. This amendment provides 
consistency with previously approved requirements in EPA Method 1631 
and with requirements proposed today (see Section V of this preamble). 
This proposal would add a footnote (17) to Table II to include 
requirements for collection, filtration, preservation, and maximum 
holding times that are specific to samples collected for determination 
of mercury using EPA Method 1631. This footnote would include the 
following requirements for mercury samples: samples must be collected 
using either fluoropolymer or glass containers, samples must be 
preserved with either HCl or BrCl within 48 hours of collection, 
preserved samples have a maximum holding time of 90 days, and samples 
must be filtered in a clean area in the laboratory or in the field 
prior to sample preservation. EPA invites comment on the proposed text 
to be added to Table II at 40 CFR 136.3(e).

VII. Administrative Requirements

A. Executive Order 12866--Regulatory Planning and Review

    Under Executive Order 12866 [58 FR 51735 (October 4, 1993)], the 
Agency must determine whether the regulatory

[[Page 51526]]

action is ``significant'' and therefore subject to Office of Management 
and Budget (OMB) review and the requirements of the Executive Order. 
The Executive Order defines ``significant regulatory action'' as one 
that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more, 
or adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    It has been determined that this rule is not a ``significant 
regulatory action'' under the terms of Executive Order 12866 and is 
therefore not subject to OMB review.

B. Regulatory Flexibility Act (RFA), as Amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et 
seq.

    The RFA generally requires an agency to prepare a regulatory 
flexibility analysis of any rule subject to notice and comment 
rulemaking requirements under the Administrative Procedure Act or any 
other statute unless the agency certifies that the rule will not have a 
significant economic impact on a substantial number of small entities. 
Small entities include small businesses, small organizations, and small 
governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the U.S. Small Business Administration definitions at 13 CFR 
121.201; (2) a small governmental jurisdiction that is a government of 
a city, county, town, school district or special district with a 
population of less that 50,000; and (3) a small organization that is 
any not-for-profit enterprise which is independently owned and operated 
and is not dominant in its field.
    After considering the economic impacts of today's proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. Today's rule 
proposes a revised version of a currently approved EPA Method to 
include additional requirements for clean techniques and quality 
control and to improve and clarify method procedures. Today's rule also 
proposes an amendment to Table II at 40 CFR 136.3(e) to provide 
consistency with previously approved requirements in Method 1631 and 
with revisions proposed today for collection, preservation, and storage 
of samples collected for determination of mercury using Method 1631 
procedures.
    Overall, the cost of these revisions are minimal. While some of the 
revisions may increase cost (e.g., clean technique and quality control 
requirements), others will provide flexibility and actually lower the 
overall analytical costs (e.g., use of new, less expensive equipment). 
Only NPDES permitting authorities must use the clean techniques. 
Permittees, including small entities, are not required to use them 
unless required to do so by their permitting authority. Many of the 
laboratories that analyze for mercury are already using the clean 
techniques, further minimizing any potential cost increases. EPA 
estimates that any costs associated with clean techniques would be 
alleviated or eliminated by the additional flexibility resulting from 
some of the proposed revisions to the Method that are discussed in 
Section V. Therefore, EPA believes that this proposed rule will not 
have a significant economic impact on a substantial number of small 
entities. We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

C. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, Tribal, and local 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, Tribal, and local governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
one year.
    Before promulgating an EPA rule for which a written statement is 
needed, section 205 of the UMRA generally requires EPA to identify and 
consider a reasonable number of regulatory alternatives and adopt the 
least costly, most cost-effective or least burdensome alternative that 
achieves the objectives of the rule. The provisions of section 205 do 
not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective or least burdensome alternative if the 
Administrator publishes with the final rule an explanation of why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including Tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for the notification of potentially affected small governments, 
enabling officials of affected small governments to have meaningful and 
timely input in the development of EPA regulatory proposals with 
significant Federal intergovernmental mandates, and informing, 
educating, and advising small governments on compliance with the 
regulatory requirements.
    EPA has determined that today's proposed rule does not contain a 
Federal mandate that may result in expenditures of $100 million or more 
for State, Tribal, and local governments, in the aggregate, or the 
private sector in any one year. This rule proposes revisions to a 
previously approved method for measuring mercury in wastewater. This 
rule also proposes to revise Table II at 40 CFR 136.3(e) to clarify 
requirements for sample collection, preservation, and storage, and to 
make these requirements consistent with previously approved 
requirements in EPA Method 1631 and with today's proposed method 
revisions. As discussed in Section VII.B regarding RFA analysis, EPA 
expects the cost of these revisions to Method 1631 to be minimal. Thus, 
today's rule is not subject to sections 202 and 205 of the UMRA. For 
the same reasons, EPA has also determined that this rule contains no 
regulatory requirements that might significantly or uniquely affect 
small governments. Thus, today's rule is not subject to the 
requirements of section 203 of the UMRA.

D. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
This rule proposes to revise a currently approved test method for use 
in water monitoring programs but does not require the use of the test 
method.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop,

[[Page 51527]]

acquire, install, and utilize technology and systems for the purposes 
of collecting, validating, and verifying information, processing and 
maintaining information, and disclosing and providing information; 
adjust the existing ways to comply with any previously applicable 
instructions and requirements; train personnel to be able to respond to 
a collection of information; search data sources; complete and review 
the collection of information; and transmit or otherwise disclose the 
information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.

E. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995, (``NTTAA''), Public Law 104-113, section 12(d) (15 U.S.C. 
272 note), directs EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., material specifications, test methods, 
sampling procedures, business practices) that are developed or adopted 
by voluntary consensus standard bodies (VCSBs). The NTTAA directs EPA 
to provide Congress, through the Office of Management and Budget (OMB), 
explanations when the Agency decides not to use available and 
applicable voluntary consensus standards.
    This proposed rulemaking involves technical standards. Therefore, 
the Agency conducted a search to identify potentially applicable 
voluntary consensus standards. However, we identified no standard for 
the measurement of mercury at low water quality criteria levels or for 
the use of ``clean techniques.'' Therefore, EPA proposes to use EPA 
Method 1631, Revision D: Mercury in Water by Oxidation, Purge and Trap, 
and Cold Vapor Atomic Fluorescence Spectrometry. EPA welcomes comments 
on this aspect of the proposed rulemaking and, specifically, invites 
the public to identify potentially applicable voluntary consensus 
standards for measuring low levels of mercury and for ``clean 
techniques'' and to explain why such standards should be used in this 
regulation.

F. Executive Order 13045--Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any 
rule that: (1) is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental 
health or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the Agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency. This 
proposed rule is not subject to the Executive Order because it is not 
economically significant as defined in Executive Order 12866, nor does 
it concern an environmental health or safety risk that EPA has reason 
to believe may have a disproportionate effect on children.

G. Executive Order 13132--Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. Today's rule proposes revisions 
to EPA's Method 1631, Revision C, for measuring mercury at low levels 
for compliance monitoring under the Clean Water Act. As discussed in 
Section VII.B regarding RFA analysis, EPA expects the cost of these 
revisions to Method 1631 to be minimal. Thus, Executive Order 13132 
does not apply to this rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

H. Executive Order 13175--Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
With Indian Tribal Governments'' (65 FR 67249, November 6, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' ``Policies that have tribal 
implications'' is defined in the Executive Order to include regulations 
that have ``substantial direct effects on one or more Indian tribes, on 
the relationship between the Federal government and the Indian tribes, 
or on the distribution of power and responsibilities between the 
Federal government and Indian tribes.''
    This proposed rule does not have tribal implications. It will not 
have substantial direct effects on tribal governments, on the 
relationship between the Federal government and Indian tribes, or on 
the distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. As 
discussed in Section VII.B regarding RFA analysis, EPA expects the cost 
of these revisions to Method 1631 to be minimal. Thus, Executive Order 
13175 does not apply to this rule.
    In the spirit of Executive Order 13175, and consistent with EPA 
policy to promote communications between EPA and tribal governments, 
EPA specifically solicits comment on this proposed rule from tribal 
officials.

I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355 (May 22, 2001)) because it is not a 
significant regulatory action under Executive Order 12866.

J. Plain Language Directive

    Executive Order 12866 requires each agency to write all rules in 
plain language. We invite your comments on how to make this proposed 
rule easier to understand. For example, have we organized the material 
to suit your needs? Are the requirements in the rule clearly stated? 
Does the rule contain technical language or jargon that isn't clear? 
Would a different format (grouping and order of sections, use of

[[Page 51528]]

headings, paragraphing) make the rule easier to understand? Would more 
(but shorter) sections be better? Could we improve clarity by adding 
tables, lists, or diagrams? What else could we do to make the rule 
easier to understand?

VIII. Request for Comments

    EPA encourages public participation in this rulemaking and is 
requesting comments on the various EPA Method 1631 revisions detailed 
in the proposal. EPA is also requesting data supporting comments, if 
available. Specifically, EPA is soliciting comments on: the proposed 
requirements for certain quality control and clean techniques that are 
currently recommended in the method and that are detailed in Section 
IVA of this preamble; the proposal to allow a discharger to elect not 
to implement the requirements at Section IVA; the proposed revisions to 
Method 1631 that address stakeholder comments and are detailed in 
Section V of this preamble; the proposed amendment to 40 CFR 136.3(e) 
Table II to include requirements for preservation and storage that are 
specific to aqueous samples collected for measurement of mercury using 
Method 1631; and the testing costs that may be associated with any of 
the proposed method modifications.
    To ensure that EPA can properly respond to comments, commenters 
should cite, where possible, the paragraph(s) or section(s) in this 
proposal or in Method EPA 1631 to which each comment refers.

List of Subjects at 40 CFR Part 136

    Environmental protection, Reporting and recordkeeping requirements, 
Water pollution control.

    Dated: September 28, 2001
Christine Todd Whitman,
Administrator.

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

PART 136--GUIDELINES ESTABLISHING TEST PROCEDURES FOR THE ANALYSIS 
OF POLLUTANTS

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

    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).

    2. Section 136.3 is amended by revising paragraph (b) (41) and by 
revising the ``Metals'' entry in Table II of paragraph (e) to read as 
follows:


Sec. 136.3  Identification of test procedures.

* * * * *
    (b) * * *
    (41) USEPA. 2001. Method 1631, Revision D, ``Mercury in Water by 
Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence 
Spectrometry.'' September 2002. Office of Water, U.S. Environmental 
Protection Agency (EPA-821-R-xx-xxx). Available from: National 
Technical Information Service, 5285 Port Royal Road, Springfield, 
Virginia 22161. Publication No. PB2001-xxxxxx. Cost: $25.50 (subject to 
change). Table IB, Note 43.
* * * * *

----------------------------------------------------------------------------------------------------------------
          Parameter No./name                Container \1\          Preservation 2, 3       Maximum holding time
---------------------------------------------------------------------------------------------------\4\----------
*                  *                  *                  *                  *                  *
                                                        *
Metals
    18. Chromium VI \7\..............  P, G...................  Cool, 4 deg.C..........  24 hours.
    35. Mercury \17\.................  P, G...................  HNO3 to pH2............  28 days.
    3, 5-8, 12,13, 19, 20, 22, 26,     P, G...................  ......do...............  6 months.
     29, 30, 32-34, 36, 37, 45, 47,
     51, 52, 58-60, 62, 63, 70-72,
     74, 75. Metals except boron,
     chromium VI and mercury \7\.
 
*                  *                  *                  *                  *                  *
                                                        *
----------------------------------------------------------------------------------------------------------------
\1\ Polyethylene (P) or glass (G). For microbiology, plastic sample containers must be made of sterilizable
  materials (polypropylene or other autoclavable plastic), except for samples collected for trace-level mercury
  (see footnote 17).
\2\ Sample preservation should be performed immediately upon sample collection. For composite chemical samples
  each aliquot should be preserved at the time of collection. When use of an automated sampler makes it
  impossible to preserve each aliquot, then chemical samples may be preserved by maintaining at 4 deg.C until
  compositing and sample splitting is completed, except for samples collected for trace-level mercury (see
  footnote 17).
\3\ When any sample is to be shipped by common carrier or sent through the United States Mails, it must comply
  with the Department of Transportation Hazardous Materials Regulations (49 CFR part 172). The person offering
  such material for transportation is responsible for ensuring such compliance. For the preservation
  requirements of Table II, the Office of Hazardous Materials, Materials Transportation Bureau, Department of
  Transportation has determined that the Hazardous Materials Regulations do not apply to the following
  materials: Hydrochloric acid (HCl) in water solutions at concentrations of 0.04% by weight or less (pH about
  1.96 or greater); Nitric acid (HNO3) in water solutions at concentrations of 0.15% by weight or less (pH about
  1.62 or greater); Sulfuric acid (H2SO4) in water solutions at concentrations of 0.35% by weight or less (pH
  about 1.15 or greater); and Sodium hydroxide (NaOH) in water solutions at concentrations of 0.080% by weight
  or less (pH about 12.30 or less).
\4\ Samples should be analyzed as soon as possible after collection. The times listed are the maximum times that
  samples may be held before analysis and still be considered valid. (See footnote 17 for samples collected for
  trace level mercury). Samples may be held for longer periods only if the permittee, or monitoring laboratory,
  has data on file to show that for the specific types of samples under study, the analytes are stable for the
  longer time, and has received a variance from the Regional Administrator under Sec.  136.3(e). Some samples
  may not be stable for the maximum time period given in the table. A permittee, or monitoring laboratory , is
  obligated to hold the sample for a shorter time if knowledge exists to show that this is necessary to maintain
  sample stability. See Sec.  136.3(e) for details. The term ``analyze immediately'' usually means within 15
  minutes or less of sample collection.
* * * * *
\7\ Samples should be filtered immediately on site before adding preservative for dissolved metals, except for
  samples collected for trace-level mercury (see footnote 17).
* * * * *
\17\ Samples collected for the determination of trace level mercury using EPA Method 1631, must be collected in
  tightly-capped fluoropolymer or glass bottles and preserved with BrCl or HCl solution within 48 hours of
  sample collection. Samples for dissolved trace level mercury must be filtered in a clean area in the field or
  the laboratory prior to sample preservation. Samples that have been preserved for determination of total or
  dissolved trace level mercury must be analyzed within 90 days of sample collection.

[FR Doc. 01-24886 Filed 10-5-01; 8:45 am]
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