`[Federal Register Volume 90, Number 12 (Tuesday, January 21, 2025)]
[Proposed Rules]
[Pages 6967-7037]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-29239]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 136

[EPA-HQ-OW-2024-0328; FRL 11799-01-OW]
RIN 2040-AG37


Clean Water Act Methods Update Rule 22 for the Analysis of 
Contaminants in Effluent

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing to 
promulgate new methods and update the tables of approved methods for 
the Clean Water Act. The Clean Water Act requires the EPA to promulgate 
test procedures for the analysis of pollutants. Promulgating new 
methods and updating the tables of approved methods increases the 
quality and consistency of data collected for the purposes of the Clean 
Water Act. In this rule, the EPA proposes to add new EPA methods for 
per- and polyfluoroalkyl substances (PFAS) and polychlorinated biphenyl 
(PCB) congeners, and add methods previously published by voluntary 
consensus bodies that industries and municipalities would use for 
reporting under the EPA's National Pollutant Discharge Elimination 
System permit program. The EPA also proposes to withdraw the seven 
Aroclor (PCB mixtures) parameters. In addition, the EPA is proposing to 
simplify the sampling requirements for two volatile organic compounds, 
and make a series of minor corrections to existing tables of approved 
methods. This proposed rule does not mandate when a parameter must be 
monitored or establish a discharge limit.

DATES: Comments must be received on or before February 20, 2025.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OW-2024-0328, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Office of Water Docket, Mail Code 28221T, 1200 Pennsylvania 
Avenue NW, Washington, DC 20460.
     Hand Delivery or Courier: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., 
Monday-Friday (except Federal Holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Adrian Hanley, Engineering and 
Analysis Division, Office of Water (4303T), Environmental Protection 
Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460-0001; 
telephone number: 202-564-1564; email address: [email protected].

SUPPLEMENTARY INFORMATION: Table of Contents
I. Public Participation
II. General Information
III. Background
IV. Corrections or Amendments to the Text and Tables of 40 CFR part 
136
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews

I. Public Participation

A. Written Comments

    Submit your comments, identified by Docket ID No. EPA-HQ-OW-2024-
0328, at https://www.regulations.gov (our preferred method), or the 
other methods identified in the ADDRESSES section. Once submitted, 
comments cannot be edited or removed from the docket. The EPA may 
publish any comment received to its public docket. Do not submit to the 
EPA's docket at https://www.regulations.gov any information you 
consider to be Confidential Business Information (CBI), Proprietary 
Business Information (PBI), or other information whose disclosure is 
restricted by statute. Multimedia submissions (audio, video, etc.) must 
be accompanied by a written comment. The written comment is considered 
the official comment and should include discussion of all points you 
wish to make. The EPA will generally not consider comments or comment 
contents located outside of the primary submission (i.e., on the web, 
cloud, or other file sharing system). Please visit https://www.epa.gov/dockets for additional submission information; the full EPA public 
comment policy; information about CBI, PBI, or multimedia submissions; 
and general guidance on making effective comments. Publicly available 
docket materials are available electronically in https://www.regulations.gov at the Water Docket in EPA Docket Center, EPA/DC, 
EPA West William J. Clinton Building, Room 3334, 1301 Constitution 
Avenue NW, Washington, DC. The Public Reading Room is open from 8:30 
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. Any 
copyright material can be viewed at the Reading Room, please contact 
the EPA Docket Center, Public Reading Room. The telephone number for 
the Public Reading Room is 202-566-1744, and the telephone number for 
the Water Docket is 202-566-2426. Fax: 202-566-9744. Email: [email protected].

[[Page 6968]]

II. General Information

A. Does this action apply to me?

    Entities potentially affected by the requirements of this action 
include:

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                                      Examples of potentially affected
             Category                             entities
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State, Territorial, and Indian      States authorized to administer the
 Tribal Governments.                 National Pollutant Discharge
                                     Elimination System permitting
                                     program; states, territories, and
                                     Tribes providing certification
                                     under CWA section 401; state,
                                     territorial, and Tribal-owned
                                     facilities that must conduct
                                     monitoring to comply with NPDES
                                     permits.
Industry..........................  Facilities that must conduct
                                     monitoring to comply with NPDES
                                     permits; the environmental
                                     monitoring industry.
Municipalities....................  Publicly Owned Treatment Works or
                                     other municipality-owned facilities
                                     that must conduct monitoring to
                                     comply with NPDES permits.
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    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 types of entities that the EPA is now aware of 
that could potentially be affected by this action. Other types of 
entities not listed in the table could also be affected. To determine 
whether your facility is affected by this action, you should carefully 
examine the applicability language at 40 CFR 122.1 (NPDES purpose and 
scope), 40 CFR 136.1 (NPDES permits and CWA) and 40 CFR 403.1 
(pretreatment standards purpose and applicability). If you have 
questions regarding the applicability of this action to a particular 
entity, consult the appropriate person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.

B. What action is the Agency taking?

    Periodically, the EPA updates the approved methods in 40 CFR part 
136. This proposed rulemaking is the 24th update to 40 CFR part 136 
since its inception in 1973, 22 Method Update Rules and two Routine 
Method Update Rules. In general, the changes in this action fall into 
six categories. The first category is withdrawal of the seven Aroclor 
parameters and associated methods. The second category is withdrawal of 
outdated methods that have been supplanted by already approved methods 
at 40 CFR part 136. The third category is a simplification of the 
sampling and preservation requirements for two volatile organic 
compound methods. The fourth category includes minor corrections in the 
text and tables in 40 CFR part 136. The EPA is proposing these 
revisions to keep current with technology advances, and to improve data 
quality and consistency for the regulated community. The fifth category 
is new EPA methods for new parameters that are being added to 40 CFR 
part 136. The sixth category is new methods published by a voluntary 
consensus standard body or vendor for new parameters. The following 
paragraphs provide details on the revisions. The first four categories 
are discussed in section IV Corrections or Amendments to the Text and 
Tables of 40 CFR part 136 of this preamble, the fifth and sixth 
categories are discussed in section V Incorporation by Reference of 
this preamble.

C. What is the Agency's authority for taking this action?

    The EPA is proposing this regulation under the authorities of 
sections 301(a), 304(h), and 501(a) of the CWA; 33 U.S.C. 1251, 
1311(a), 1314(h) and 1361(a). Section 301(a) of the CWA prohibits the 
discharge of any pollutant into navigable waters unless the discharge 
complies with, among other provisions, a NPDES permit issued under 
section 402 of the CWA. Section 304(h) of the CWA requires the EPA 
Administrator 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 the CWA] or permit application pursuant to [section 402 
of the CWA].'' Section 501(a) of the CWA authorizes the EPA 
Administrator to ``. . . prescribe such regulations as are necessary to 
carry out this function under [the CWA].'' The EPA generally has 
codified its test procedure regulations (including analysis and 
sampling requirements) for CWA programs at 40 CFR part 136, though some 
requirements are codified in other parts (e.g., 40 CFR Chapter I, 
Subchapters N and O).

III. Background

    This preamble describes the abbreviations and acronyms used, the 
legal authority and reasons for the proposed rule, and a summary of the 
proposed changes and clarifications, and solicits comment from the 
public.

Abbreviations and Acronyms Used in the Preamble

AOF: Adsorbable Organic Fluorine
ASTM: ASTM International \1\
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    \1\ Formerly known as the American Society for Testing and 
Materials (ASTM).
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CFR: Code of Federal Regulations
CWA: Clean Water Act
EPA: The U.S. Environmental Protection Agency
GC/MS: Gas Chromatography/Mass Spectrometry
H2O2: Hydrogen Peroxide
ICP/AES: Inductively Coupled Plasma-Atomic Emission Spectroscopy
LC-MS/MS: Liquid Chromatography-Tandem Mass Spectrometry (also used 
as LC/MS/MS in some methods)
NPDES: National Pollutant Discharge Elimination System
NTTAA: National Technology Transfer and Advancement Act
PAA: Peracetic Acid
PCB: Polychlorinated Biphenyl
PFAS: Per- and Polyfluoroalkyl Substances
POTW: Publicly Owned Treatment Works
QC: Quality Control
TNI: The NELAC Institute
USGS: United States Geological Survey
VCSB: Voluntary Consensus Standards Body

    NPDES permits must include conditions to ensure compliance with the 
technology-based and water quality-based requirements of the CWA, 
including in many cases, restrictions on the quantity of specific 
pollutants that can be discharged. Permittees must use EPA-approved 
analytical methods that are sensitive enough to detect and measure 
pollutants at or below permit limits or water quality criteria (CWA 
section 402(b)(2)(A)). Permits include measurement and reporting 
requirements for these specific pollutants; however, permittees often 
have a choice of which approved test procedure they will use when the 
EPA has approved more than one method for a specific pollutant.
    The procedures for the analysis of pollutants required by CWA 
section 304(h) are a central element of the NPDES permit program. 
Examples of

[[Page 6969]]

where these EPA-approved analytical methods must be used include the 
following: (1) applications for NPDES permits, (2) sampling or other 
reports required under NPDES permits, (3) other requests for 
quantitative or qualitative effluent data under the NPDES regulations, 
(4) State CWA 401 certifications, and (5) sampling and analysis 
required under EPA's General Pretreatment Regulations for Existing and 
New Sources of Pollution, 40 CFR 136.1, 40 CFR 403.12(b)(5)(v), and 40 
CFR 403.12(g)(3).
    Periodically, the EPA promulgates updates to the approved methods 
in 40 CFR part 136 to improve data quality and consistency. The changes 
proposed in this action fall into the following categories. The first 
category is withdrawal of seven Aroclor mixtures and the associated 
approved methods for Aroclors from the list of parameters at Table Ic 
that have been replaced with a method for the PCB congeners and total 
PCBs at Table Ii that provides a more accurate and complete 
characterization of the PCB content of samples than Aroclor analyses 
(see section V.A of this preamble). The second category is withdrawal 
of outdated methods that includes single-analyte total metal 
colorimetric methods for twelve metal parameters, a Waters\TM\ anion 
method, and EPA Method 1664A for the parameter ``oil and grease'' (see 
section IV.B of this preamble). The third category is simplifying 
sampling requirements for purgeable compounds by making the 
preservation requirement for acrolein and acrylonitrile consistent with 
the other pollutants analyzed by volatile organic compound methods (see 
section IV.C of this preamble). The fourth category is minor 
corrections to the text and tables at 40 CFR part 136 (see section IV.D 
of this preamble). The fifth category is new EPA methods for new 
parameters not previously listed at 40 CFR part 136 that will be added 
by incorporation by reference: per- and polyfluoroalkyl substances 
(PFAS) by EPA Method 1633A to a new Table Ij, adsorbable organic 
fluorine (AOF) by EPA Method 1621 to Table Ic, and polychlorinated 
biphenyl (PCB) congeners by EPA Method 1628 to a new Table Ii (see 
section V.A of this preamble). The EPA has finalized these three EPA 
methods and has posted these methods, along with their validation study 
reports, on EPA's CWA Methods website (https://www.epa.gov/cwa-methods). The sixth category is new methods published by the voluntary 
consensus standard bodies (VCSBs) or vendors for new parameters not 
previously listed at 40 CFR part 136 that will be added by 
incorporation by reference: PFAS analytes by ASTM D8421-24 to Table Ij; 
peracetic acid (PAA) by Standard Method ``4500-PAA Peracetic Acid 
(Residual),'' and hydrogen peroxide (H2O2) by 
Standard Method ``4500-H2O2 Hydrogen Peroxide 
(Residual)'' to Table Ib (see section V.B of this preamble). Finally, 
as a consequence of adding the two new tables for the PCB congeners and 
PFAS, the format of the numbers for the existing Tables IA through IH 
are being revised to be called out as Tables Ia through Ih. The use of 
a lowercase letter in the table identifier is necessary to avoid 
confusion between the new Table Ii of PCB congeners and the existing 
Table II with the required containers, preservation techniques, and 
holding times (see section V.A of this preamble).

IV. Corrections or Amendments to the Text and Tables of 40 CFR Part 136

A. Withdrawal of the Aroclor Parameters and the Associated Methods

    The EPA proposes to withdraw the seven Aroclor parameters listed as 
PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-
1260 and their associated methods from Table Ic, Parameters 88-94. 
Removing these parameters will result in the renumbering of all of the 
subsequent parameters in that table. This will also result in deletion 
of footnote 8, and the renumbering of footnotes 9 through 16. All of 
the methods listed for these parameters are listed elsewhere for other 
parameters, so none of them will be completely removed from 40 CFR part 
136.3. The ``PCBs'' class of compounds is made up of 209 structurally 
related but distinct chemicals often called ``congeners.'' The seven 
Aroclor parameters are commercial PCB mixtures and were first included 
in the EPA's 1976 Priority Pollutant List (Appendix A to Part 423, 
Title 40). These seven PCB mixtures were the only ones for which the 
EPA had valid methods at that time. However, none of these Aroclor 
mixtures include all the PCB congeners that may be present in an 
environmental sample. The EPA developed the original Aroclor methods in 
the 1970s, when analysis of individual PCB congeners was impractical 
with the existing affordable analytical technology and in the absence 
of automated laboratory information management systems. During the 
multi-laboratory study of Method 608 in the late 1970s, roughly 20% of 
the Aroclor data were rejected due to poor accuracy, and false 
negatives (non-detects) were an issue even with samples that were 
spiked with fresh standards.\2\
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    \2\ EPA document EPA-600/4-84-061, ``EPA Method Study 18 Method 
608--Organochlorine Pesticides and PCBs.'' June 1984.
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    When used as a surrogate for PCBs, the results from the approved 
Aroclor methods can create false confidence that PCBs are not present. 
Given that the manufacturing and use of PCBs have been banned in the 
U.S. since 1979, most PCBs in the environment have been subjected to 
extensive changes in composition and concentration through processes 
that are collectively referred to as ``weathering.'' Moreover, there 
are other relevant sources of PCBs to the environment beyond the seven 
Aroclor parameters that are not accounted for through Aroclor analyses. 
Aroclor methods were the best available technology when they were 
validated in 1978, but now there are much more accurate methods. Thus, 
the EPA is proposing to replace the Aroclor analysis with EPA Method 
1628, which detects the 209 PCB congeners directly, either as 
individual congeners or groups of co-eluting congeners. As demonstrated 
by the EPA's multi-laboratory study,\3\ EPA Method 1628 can be widely 
implemented because it uses laboratory equipment that is readily 
available and is already employed by many full-service laboratories.
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    \3\ EPA document EPA 820-R-21-003, ``Report on the Multi-
laboratory Validation of Clean Water Act Method 1628 for PCB 
Congeners.'' April 2021.
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    Withdrawal of the Aroclor parameters and associated methods will 
not have any immediate impact on current NPDES permits because permits 
that have been issued by the permitting authority can continue until 
they expire. 40 CFR 122.21(e)(3)(ii) states: ``(ii) When there is no 
analytical method that has been approved under 40 CFR part 136, 
required under 40 CFR chapter I, subchapter N or O, and is not 
otherwise required by the Director, the applicant may use any suitable 
method but shall provide a description of the method. When selecting a 
suitable method, other factors such as a method's precision, accuracy, 
or resolution, may be considered when assessing the performance of the 
method.'' EPA anticipates renewed permits will switch to the approved 
PCB congener method. Given that most permits are renewed every 5 years 
or less, promulgation of this part of this proposed rule would result 
in a multi-year phase out of Aroclor analysis.

B. Withdrawal of Outdated Methods

    The EPA proposes to withdraw approval of outdated colorimetric

[[Page 6970]]

methods for 12 individual metals and one inorganic anions alternate 
test procedure that the sponsoring organization no longer supports or 
makes available to the public. The removal of these methods and their 
associated footnotes will result in renumbering of the following 
footnotes at the end of Table Ib.
    1. The EPA proposes to withdraw 12 single-metal colorimetric 
methodology types that measure a total metal concentration (e.g., 
``Aluminum--Total'') from 40 CFR 136.3, Table Ib. There are multiple 
inductively coupled plasma (ICP) and graphite furnace methods that are 
more sensitive and provide more accurate results in challenging 
matrices that are already listed in Table Ib. These ICP and graphite 
furnace methods are also relatively inexpensive and easily automated, 
particularly when analyzing for one parameter (as is done for the 
colorimetric methods that the EPA is proposing to withdraw). The 
suggestion to withdraw these methods initially came from The NELAC 
Institute (TNI), which accredits a large portion of the environmental 
laboratories in the U.S. TNI is unaware of any laboratory that is 
currently accredited for these outdated colorimetric methods. If the 
EPA receives compelling reason to not withdraw any of these methods, 
the EPA will consider keeping some or all of these methods in 40 CFR 
part 136. Otherwise, the EPA proposes to withdraw the methods in the 
rows where ``Colorimetric'' is the listed methodology for the following 
total metals, listed in order of the parameter number in Table Ib: 3. 
Aluminum--Total, 6. Arsenic--Total, 8. Beryllium--Total, 10. Boron--
Total, 12. Cadmium--Total, 19. Chromium--Total, 22. Copper--Total, 30. 
Iron--Total, 32. Lead--Total, 34. Manganese--Total, 74. Vanadium--
Total, and 75. Zinc--Total. In addition, footnotes pertaining to only 
these withdrawals will be removed and the remaining footnotes 
renumbered sequentially. The relevant methods that will be withdrawn 
are listed here by organization. Standard Methods: 3500-Al B-2020, 
3500-As B-2020, 4500-B B-2011, 3500-Cd D-1990, 3500-Cr B-2020, 3500-Cu 
B and C-2020, 3500 Fe B-2011, 3500-Pb B-2020, 3500-Mn B-2020, 3500-V B-
2011, 3500-Zn B-2020, and Footnote 61 that references an aluminon 
colorimetric method in Standard Methods 19th Edition. ASTM: D2972-15 
(A), D1068-15 (C). USGS: Methods I-3060-85 and I-3112-85. Hach: 
Footnote 19 that references Method 8506, Bicinchoninate Method for 
Copper, Hach Handbook of Water Analysis, 1979; Footnote 22 that 
references Method 8008, 1,10-Phenanthroline Method using FerroVer Iron 
Reagent for Water, 1980; Footnote 23 that references Method 8034, 
Periodate Oxidation Method for Manganese, Hach Handbook of Wastewater 
Analysis, 1979; and Footnote 33 that references Method 8009, Zincon 
Method for Zinc, Hach Handbook of Water Analysis, 1979. AOAC 
International: Footnote 3 that references Method 920.203, the 
persulfate oxidation procedure from the Official Methods of Analysis of 
the Association of Official Analytical Chemists, Methods Manual, 
Sixteenth Edition, 4th Revision, 1998.
    2. The EPA also proposes to withdraw from Table Ib the Waters\TM\ 
Corporation alternate test procedure: ``Method D6508 Rev.2, Test Method 
for Determination of Dissolved Inorganic Anions in Aqueous Matrices 
Using Capillary Ion Electrophoresis and Chromate Electrolyte.'' The 
Waters\TM\ Corporation no longer supports this method and no longer 
provides copies of this method to the public. Waters\TM\ developed 
their alternative test procedure to incorporate additional analysis 
techniques into an older ASTM standard. The method modifications 
developed by Waters\TM\ were incorporated into later versions of the 
ASTM standard, including D6508-15, which is the currently approved 
method for the same anions: bromide, chloride, fluoride, nitrate, 
nitrate-nitrite, nitrite, orthophosphate, and sulfate (86 FR 27226, May 
19, 2021). Both the Waters\TM\ and ASTM methods are capillary ion 
electrophoresis methods that provide a simultaneous separation and 
determination of several inorganic anions and identifies all anions 
present in the sample by indirect UV detection. The EPA proposes to 
remove the eight occurrences of Method D6508 Rev. 2 from Table Ib. They 
are found in parameters: 11. Bromide, 16. Chloride, 25. Fluoride-Total, 
38 Nitrate (as N), 39. Nitrate-nitrite (as N), 40. Nitrite (as N), 44. 
Ortho-phosphate (as P), and 65. Sulfate (as SO4).
    3. The EPA proposes to withdraw EPA Method 1664, Revision A: N-
Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel 
Treated N-Hexane Extractable Material (SGTHEM; Non-polar Material) by 
Extraction and Gravimetry, approved at 64 FR 26315, May 14, 1999, from 
Table Ib, parameter 41. A later revision of Method 1664, (1664 Rev. B), 
was approved by the EPA in a 2012 rulemaking, 77 FR 29758, May 18, 
2012. That 2012 rule strongly recommended laboratories and permitting 
authorities replace Method 1664, Rev. A with Method 1664, Rev. B. The 
2012 rule also said that the EPA would revisit withdrawing Method 1664, 
Rev. A in a future rulemaking (77 FR 29758, May 18, 2012). Laboratories 
and regulatory entities have had more than 12 years to make this 
adjustment, so the EPA is proposing to withdraw Method, 1664, Rev. A 
from Table Ib, for parameter 41. Oil and Grease--Total recoverable.

C. Simplify the Sampling and Preservation Requirements for Two 
Purgeable Organic Compounds (Often Referred to as Volatile Organic 
Compounds)

    The EPA proposes to change the sampling and preservation 
requirements for acrolein and acrylonitrile to match those of the other 
purgeable halocarbons and purgeable aromatic hydrocarbons in Table II 
under the section for parameters in Table Ic. The EPA proposes to 
change the preservation pH requirement from pH 4-5 to a pH of 2, and to 
use hydrochloric acid to adjust the sample pH, to align with the 
approved practice for other purgeable organic compounds. The 
Environmental Monitoring Coalition provided the EPA with the results 
from a study using multiple wastewater types that demonstrated that the 
analysis of acrolein and acrylonitrile is not adversely affected by the 
lower pH preservation. That Environmental Monitoring Coalition study 
report: ``Evaluating Preservation Requirements for Acrolein and 
Acrylonitrile in Aqueous Matrices,'' is provided in the docket. Thus, 
the EPA is proposing these changes to make the sampling, analysis, and 
data reporting more efficient for purgeable organic compound methods.

D. Minor Corrections and Amendments to the Texts and Tables of 40 CFR 
Part 136

    Stakeholders have identified several minor errors in Tables Ib, Id, 
and II. The EPA proposes to correct the following entries in those 
tables.
    1. The EPA proposes to remove the row for the methodology 
``Amperometric direct (low level)'' in Table Ib, parameter 17A, 
Chlorine-Free Available, because the only method listed in that row, 
Standard Method 4500 Cl E, measures Total Residual Chlorine (e.g., 
parameter 17), not free chlorine. The method will remain in the 
corresponding row for Residual Chlorine parameter 17, where the 
parameter matches the method.
    2. The EPA proposes to amend Table Ib parameter 24 by adding 4500-
CN P-2021 and D7511(17) to allow use of any method approved for 
measurement of Total Cyanide in both the untreated and

[[Page 6971]]

treated fractions of a sample for determination of available cyanide by 
cyanide amenable to chlorination (CATC), provided the treatment steps 
in the two currently approved amenable cyanide methods, 4500-CN G-2016 
and ASTM D2036-09(15)(B), are followed.
    3. The EPA proposes to add EPA Method 625.1 as an approved method 
for the parameter Parathion ethyl, parameter 53 in Table Id. The use of 
EPA Method 625.1 was incorrectly omitted from Table Id for this 
parameter the last time that Table Id was updated (82 FR 40836, August 
28, 2017) because the method lists this analyte as ``Parathion,'' 
rather than Parathion ethyl. EPA Method 625.1 measures aqueous samples 
by extracting them with methylene chloride at pH 11--13 and again at a 
pH less than 2 using a separatory funnel or continuous liquid/liquid 
extractor. Then the extract is concentrated and analyzed by GC/MS.
    4. The EPA proposes to apply footnote 9 to the entry for EPA Method 
1613B in Table Ic for parameter 96, 2,3,7,8-Tetrachloro-dibenzo-p-
dioxin (formerly listed a parameter 103). This footnote (formerly 
listed as footnote 10) was to be added to all 17 dioxin and furan 
congeners in a previous rule (88 FR 10739, February 21, 2023) but was 
inadvertently missed for this parameter.
    5. The EPA proposes to add sodium thiosulfate, 
Na2S2O3, to the preservation column 
for parameter 4, Ammonia, under Table Ib in Table II, and apply 
Footnote 5 to that entry to address the fact that residual chlorine in 
samples will react with ammonia to form chloramines, which are an 
interference with ammonia analyses. The EPA also is adding the 
following text to the end of Footnote 5, ``Section A.2 of Standard 
Method 4500-NH3 discusses the need for dechlorination of samples for 
ammonia analysis.''
    6. The EPA proposes to edit Footnote 17 to Table II under the 
section for parameters in Table Ib, as applied to parameter 35 for 
``Mercury (CVAFS)'' to include mention of EPA Method 245.7 along with 
EPA Method 1631 in the footnote. Both methods employ the same cold 
vapor atomic fluorescence spectroscopy (CVAFS) determinative technique 
and including EPA Method 245.7 in the footnote will help clarify that 
the 90-day holding time applies to EPA Method 245.7 as well as EPA 
Method 1631. Currently, Method 245.7 is not specifically mentioned in 
Table II, which was an oversight.
    7. The EPA proposes to specify in Table II that sodium thiosulfate 
is to be added to samples to remove oxidants (e.g., chlorine) for the 
Table 1B parameter 48 (Phenols) and the Table 1C parameters 107 to 111 
(Alkylated phenols). The EPA also proposes to restore footnote 5 in 
Table II for Table 1C parameters 23, 30, 44, 49, 53, 77, 80, 81, 91, 
93, and 105 (Phenols), and to add Footnote 5 for Table 1C parameters 
112 (Adsorbable Organic Halides) and 113 (Chlorinated Phenolics), and 
to clarify that the addition of sodium thiosulfate is only necessary 
when oxidants are present (e.g., chlorine).
    8. The EPA proposes to add a new footnote to Table II under Table 
Ib and apply it to the entry for parameter 50, Phosphorus--Total. The 
new Footnote 25 addresses the fact that many laboratories determine 
total phosphorus using EPA Method 200.7, an ICP/AES procedure for 
metals that is also approved for phosphorus. However, as laboratories 
often note, the acid specified in Table II to preserve metals samples 
is nitric acid, where Table II calls out sulfuric acid for phosphorous. 
In both cases the specified pH is a value less than or equal to 2. In 
addition, while Table II allows acidified samples to held for 6 months, 
it only allows phosphorus samples to be held for 28 days. The new 
Footnote 25 reads: ``When EPA Method 200.7 or another approved ICP/AES 
method is used to determine total phosphorus, sulfuric acid may be used 
to preserve the sample to pH <= 2, or the acid-preserved sample for 
metals may be used for analysis, and the holding time for total 
phosphorus may be extended to 6 months.''

V. Incorporation by Reference

    Currently, hundreds of methods and alternate test procedures are 
incorporated by reference within 40 CFR part 136. In most cases, 40 CFR 
part 136 contains multiple approved methods for a single parameter (or 
pollutant) and regulated entities often have a choice in selecting a 
method. The proposed rule contains VCSB methods that are incorporated 
by reference (see section V.B of this preamble). The proposed VCSB 
methods are consistent with the requirements of the National Technology 
Transfer and Advancement Act (NTTAA), under which Federal agencies 
should use technical standards developed or adopted by the VCSBs if 
compliance would not be inconsistent with applicable law or otherwise 
impracticable (see section VI of this preamble). The proposed 
copyrighted VCSB methods are available on their respective websites 
(standardmethods.org and astm.org) to everyone at a cost determined by 
the VCSB, generally from $60 to $80. Both organizations also offer 
memberships or subscriptions that allow unlimited access to their 
methods. The cost of obtaining these methods is not a significant 
financial burden for a discharger or environmental laboratory, making 
the methods reasonably available.
    This proposal includes EPA Method 1621, EPA Method 1628, and EPA 
Method 1633A (see section V.A of this preamble) and ASTM D8421-24, 
Standard Method ``4500-PAA Peracetic Acid (Residual)'', and Standard 
Method ``4500-H2O2 Hydrogen Peroxide (Residual)'' for four parameter 
types (see section V.B of this preamble) which the EPA proposes to 
incorporate by reference. The EPA methods and the vendor methods are 
available free of charge on their respective websites, therefore the 
EPA methods and vendor methods incorporated by reference are reasonably 
available.
    Other standards appear in the amendatory text of this document and 
have already been approved for the locations in which they appear.

A. Changes to 40 CFR 136.3 To Include Three New EPA Methods and Their 
Associated Parameters

    The EPA proposes to add three new EPA methods and their associated 
parameters to 40 CFR 136.3: EPA Method 1621: Determination of 
Adsorbable Organic Fluorine (AOF) in Aqueous Matrices by Combustion Ion 
Chromatography (CIC), EPA Method 1628: Polychlorinated Biphenyl (PCB) 
Congeners in Water, Soil, Sediment, Biosolids, and Tissue by Low-
resolution GC/MS using Selected Ion Monitoring, and EPA Method 1633A: 
Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous, 
Solid, Biosolids, and Tissue Samples by LC-MS/MS. All three of these 
methods have multi-laboratory validation studies that demonstrate they 
perform well in a wide variety of wastewater types at multiple 
laboratories. These methods include performance (or quality control) 
criteria that the EPA generated by statistically analyzing the data 
from the multi-laboratory validation studies. The multi-laboratory 
validation study reports and methods are available to the public on the 
EPA's Clean Water Act Analytical Methods website at https://www.epa.gov/cwa-methods, and in the docket to this proposed rulemaking.
    Adding these methods and parameters to 40 CFR part 136 does not 
require the permitting authority to require monitoring for those 
parameters, but it informs the permitting authority and discharger that 
there is an available method that has been validated and tested. Once 
these methods are finalized in 40 CFR part 136, then use of the 
approved test procedure is required if

[[Page 6972]]

any of these parameters are added to a NPDES permit. The EPA proposes 
to add the parameter ``Adsorbable Organic Fluorine,'' (AOF) to Table Ic 
with the approved test procedure EPA Method 1621. EPA Method 1621 
determines adsorbable organic fluorine by passing an aqueous sample 
through two granular activated carbon columns. The columns are rinsed 
with sodium nitrate to remove inorganic fluoride, combusted at >=1000 
[deg]C in an oxygen or oxygen/argon stream, and the gaseous hydrogen 
fluoride is absorbed into reagent water. The fluoride is separated by 
ion chromatography (IC), identified by comparing sample fluoride 
retention time to retention times for calibration standards acquired 
under identical Ic conditions, and then quantified using the external 
standard technique.
    The EPA proposes to redesignate all tables in 136.3 with a lower 
case letter, for example Table IA would be ``Table Ia--List of Approved 
Biological Methods for Wastewater and Sewage Sludge.'' This 
redesignation of the table titles is needed to avoid confusion with the 
currently existing Table II (Roman numeral two) and the new table for 
PCBs in order to distinguish between Roman numeral one followed by the 
letter ``I'' and Roman numeral two. Then Tables Ii and Ij will be 
added, as discussed below. The number format for Table II--Required 
Containers, Preservation Techniques, and Holding Times will remain 
unchanged.
    The EPA proposes to add the 209 Polychlorinated Biphenyl (PCB) 
Congeners and Total PCBs as new parameters in a new Table Ii with the 
approved test procedure EPA Method 1628. Method 1628 detects all PCB 
209 congeners, which are all the compounds that make up the class of 
chemicals called ``PCBs.'' The new parameter called ``Total PCBs'' will 
be the summation of all the detected PCB congeners in the sample as 
determined by Method 1628. The summation will use zero (0) for the 
contribution of the congeners that are not detected. Otherwise, every 
method blank would have a non-zero result, even when no congeners are 
detected, affecting assessments of the sample results relative to the 
method blank. There is no method detection limit (MDL) for Total PCBs 
because it is the sum of the results for many individual parameters. 
Method blanks and samples with no detects are reported as ``ND'' for 
non-detect, or a similarly appropriate non-numeric value. Method 1628 
analyzes samples by spiking them with isotope dilution standards, 
extracting the PCBs using separatory funnel extraction or solid-phase 
extraction, cleaning the extracts with a Florisil[supreg] column, and 
analyzing the sample extracts using GC/MS with selected ion monitoring. 
Because the full names of the PCB congeners are long and contain many 
numbers indicating the positions of the chlorine substituents (e.g., 
2,3,3',4,4',5-Hexachlorobiphenyl), they are often expressed as a 
``congener number'' in the format ``PCB-XYZ,'' where ``XYZ is a number 
between 1 and 209. The EPA has included the congener numbers in Table 
Ii to facilitate consistency in reporting of the results for these new 
parameters.
    The EPA proposes to add the 40 target PFAS analytes in Method 1633A 
as new parameters in a new Table Ij, with the approved test procedure 
EPA Method 1633A. Method 1633A analyzes samples by spiking them with 
isotope dilution standards, subjecting them to solid-phase extraction 
and activated carbon cleanup, and analyzing the sample extracts using 
liquid chromatography-tandem mass spectrometry (LC-MS/MS).
    The EPA proposes to add these new parameters to the relevant 
section of Table II--Required Containers, Preservation Techniques, and 
Holding Times. The specifications for the containers, preservation 
techniques, and holding times for these parameters are the same as the 
specifications provided in the method.

B. Changes to 40 CFR 136.3 To Include New Parameters and Methods 
Published by VCSBs and Vendors

    The EPA solicited VCSBs and relevant vendors to submit methods, 
along with study reports and validation data, for the following 
parameters: the PFAS parameters listed in Method 1633A, peracetic acid, 
and hydrogen peroxide. The VCSBs or vendors submitted data that 
demonstrate that their methods can be used at multiple laboratories and 
can reliably detect and quantify the parameter in a wide variety of 
wastewater types (as the EPA does with its own CWA methods). The 
methods and multi-laboratory study reports for each of the following 
methods are in the docket for this rulemaking. The EPA proposes to add 
the following parameters and methods to 40 CFR part 136.
    The EPA also proposes to add these new parameters to the relevant 
section of Table II--Required Containers, Preservation Techniques, and 
Holding Times. The specifications for the containers, preservation 
techniques, and holding times for peracetic acid, and hydrogen peroxide 
are the same as the specifications provided in the methods. The 
preservation and holding time specifications for the PFAS parameters 
parallel those from EPA Method 1633A.
    1. ``ASTM D8421-24 Standard Test Method for Determination of Per- 
and Polyfluoroalkyl Substances (PFAS) in Aqueous Matrices by Co-
solvation followed by Liquid Chromatography Tandem Mass Spectrometry 
(LC/MS/MS),'' as an approved test procedure for the 40 PFAS analytes 
being added as new parameters in Table Ij. ASTM D8421-24 analyzes 
aqueous samples by adding labeled surrogates to a 5-mL sample in the 
original container, adding 5 mL of methanol, filtering the sample, 
adjusting the pH and injecting a small aliquot of the extract into an 
LC-MS/MS instrument.
    2. The EPA proposes to add the parameter ``Peracetic acid (PAA)'' 
to Table Ib and approve Standard Method ``4500-PAA Peracetic Acid 
(Residual).'' This method uses a simple handheld instrument that uses 
N,N-diethyl-p-phenylenediamine (DPD) chemical indicator (for PAA) 
followed by colorimetric detection. It is similar to the colorimetric 
methods used for residual chlorine. This new parameter will provide 
POTWs and other wastewater treatment permittees that utilize peracetic 
acid as an alternative to chlorine-based disinfectants with an approved 
method to monitor their discharges.
    3. The EPA also proposes to add the parameter ``Hydrogen Peroxide 
(H2O2),'' to Table Ib and approve Standard Method 
``4500-H2O2 Hydrogen Peroxide (Residual).'' This 
method uses a simple handheld instrument that uses ferric thiocyanate 
chemical indicator (for H2O2) followed by 
colorimetric detection. It is similar to the colorimetric methods used 
for residual chlorine. Hydrogen peroxide is a by-product of the use of 
Peracetic acid as an alternative to chlorine-based disinfectants and in 
conjunction with the addition of the new parameter ``Peracetic acid 
(PAA),'' Standard Method ``4500-H2O2 Hydrogen 
Peroxide (Residual) will provide POTWs and other wastewater treatment 
permittees that utilize peracetic acid with approved methods to monitor 
their discharges.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review Executive 
Order 14094: Modernizing Regulatory Review

    This action is not a significant regulatory action as defined in 
Executive Order 12866, as amended by Executive Order 14094, and was 
therefore not subject to a requirement for Executive Order 12866 
review.

[[Page 6973]]

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the Paperwork Reduction Act. This rule does not impose any information 
collection, reporting, or recordkeeping requirements. This proposal 
would merely add or revise CWA test procedures.

C. Regulatory Flexibility Act

    I certify that this action would not have a significant economic 
impact on a substantial number of small entities under the Regulatory 
Flexibility Act. This action would not impose any requirements on small 
entities. This action would approve new and revised versions of CWA 
testing procedures. Generally, these changes improve data quality. In 
general, the EPA expects the proposed revisions would lead to few 
direct costs. Adding these parameters and methods to 40 CFR part 136 
does not require the permitting authority to require monitoring that 
parameter, but it informs the permitting authority and discharger that 
there is an available method that has been validated and tested in a 
wide variety of wastewater types. If a permittee is already monitoring 
for one of more of the parameters, then the permittee may need to 
change methods. This would not be a significant change in cost, given 
that the permittee is already paying a laboratory to analyze for the 
parameter(s). The EPA proposes methods that would be incorporated by 
reference. If a permittee elected to use these methods, they could 
incur a small cost associated with obtaining these methods from the 
listed sources. See section IV of this preamble.

D. Unfunded Mandates Reform Act

    This action does not contain an unfunded mandate as described in 
the Unfunded Mandates Reform Act, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The action imposes 
no enforceable duty on any state, local or tribal governments or the 
private sector.

E. Executive Order 13132: Federalism

    This proposed rule does not have federalism implications. It would 
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.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This proposed rule does not have tribal implications as specified 
in Executive Order 13175. This rule would merely approve new and 
revised versions of test procedures. The EPA does not expect the 
proposal would lead to any costs to any tribal governments, and if 
incurred, the EPA projects they would be minimal. Thus, Executive Order 
13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. Therefore, this action is not 
subject to Executive Order 13045 because it does not concern an 
environmental health risk or safety risk. Since this action does not 
concern human health, the EPA's policy on Children's Health also does 
not apply.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act of 1995

    This action involves technical standards. The EPA proposes to 
approve the use of technical standards developed and recommended by the 
Standard Methods Committee and ASTM International for use in compliance 
monitoring where the EPA determined that those standards meet the needs 
of CWA programs. As described above, this proposal is consistent with 
the NTTAA.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations and 
Executive Order 14096: Revitalizing Our Nation's Commitment to 
Environmental Justice for All

    The EPA believes that this type of action does not concern human 
health or environmental conditions and therefore cannot be evaluated 
with respect to potentially disproportionate and adverse effects on 
communities with environmental justice concerns.
    This action has no effect on communities because this action will 
approve new CWA testing procedures. These changes would provide 
increased flexibility for the regulated community in meeting monitoring 
requirements while improving data quality. Adding new parameters to 40 
CFR part 136 does not require the parameters to be monitored. In 
addition, this update to the CWA methods will incorporate technological 
advances in analytical technology. Although this action does not 
concern human health or environmental conditions, the EPA identifies 
and addresses environmental justice concerns by identifying and 
addressing, as appropriate, disproportionately high and adverse human 
health or environmental effects of their programs, policies, and 
activities on minority populations (people of color) and low-income 
populations.

List of Subjects in 40 CFR Part 136

    Environmental protection, Incorporation by reference, Reporting and 
recordkeeping requirements, Test procedures, Water pollution control.

Michael S. Regan,
Administrator.
    For the reasons set forth in the preamble, the EPA proposes to 
amend 40 CFR part 136 as follows:

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

0
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).
0
2. Amend Sec.  136.3 by:
0
a. Redesignating tables IA through IH as tables Ia through Ih, 
respectively;
0
b. In paragraph (a):
0
i. Revising the introductory text;
0
ii. Revising newly redesignated tables Ib and Ic;
0
iii. In newly redesignated table Id, revising the third column heading 
and the entry for ``53. Parathion ethyl'';
0
iv. Adding in alphabetical order tables Ii and Ij; and
0
c. In paragraph (b):
0
i. Revising the introductory text;
0
ii. Redesignating paragraphs (b)(8)(xi) through (xvi) as paragraphs 
(b)(8)(xiv) through (xix) and adding new paragraphs (b)(8)(xi) through 
(xiii);
0
iii. Revising and republishing paragraph (b)(10);

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0
iv. Removing paragraph (b)(13)(i)(A), and redesignating paragraphs 
(b)(13)(i)(B) through (X) as paragraphs (b)(13)(i)(A) through (W);
0
v. Adding paragraph (b)(15)(lxxi);
0
vi. Removing paragraphs (b)(20)(ii) through (v), and redesignating 
paragraphs (b)(20)(vi) through (x) as paragraphs (b)(ii) through (vi);
0
vii. Revising paragraph (b)(38)(i); and
0
viii. Removing paragraph (b)(41).
0
d. In paragraph (e), table II:
0
i. Redesignating entries ``Table IA'' through ``Table IH'' as ``Table 
Ia'' ``through Table Ih'', respectively;
0
ii. Revising the entry for ``4. Ammonia'' under Table Ib-Inorganic 
Tests;
0
iii. Revising entries for ``48. Phenols'' and ``50. Phosphorus, 
total'', and adding entries for ``77. Hydrogen Peroxide'' and ``78. 
Peracetic Acid'' under Table Ib--Metals;
0
iv. Revising the table entitled ``Table Ic-Organic Tests'';
0
v. Adding in alphabetical order entries for ``Table Ii--Polychlorinated 
Biphenyl Congener Tests'' and ``Table Ij--Per- and Polyfluorinated 
Alkyl Substances Tests'';
0
vi. Revising footnotes 5 and 17 and
0
vii. Adding footnotes 25 through 29.
    The revisions and additions read as follows:


Sec.  136.3  Identification of test procedures

    (a) Parameters or pollutants, for which methods are approved, are 
listed together with test procedure descriptions and references in 
Tables Ia, Ib, Ic, Id, Ie, If, Ig, Ih, Ii, and Ij of this section. The 
methods listed in Tables Ia, Ib, Ic, Id, Ie, If, Ig, Ih, Ii, and Ij are 
incorporated by reference, see paragraph (b) of this section, with the 
exception of EPA Methods 200.7, 601-613, 624.1, 625.1, 1613, 1624, and 
1625. The full texts of Methods 601-613, 624.1, 625.1, 1613, 1624, and 
1625 are printed in appendix A of this part, and the full text of 
Method 200.7 is printed in appendix C of this part. The full text for 
determining the method detection limit when using the test procedures 
is given in appendix B of this part. In the event of a conflict between 
the reporting requirements of 40 CFR parts 122 and 125 and any 
reporting requirements associated with the methods listed in these 
tables, the provisions of 40 CFR parts 122 and 125 are controlling and 
will determine a permittee's reporting requirements. The full texts of 
the referenced test procedures are incorporated by reference into 
Tables Ia, Ib, Ic, Id, Ie, If, Ig, Ih, Ii, and Ij. The year after the 
method number indicates the latest editorial change of the method. The 
discharge parameter values for which reports are required must be 
determined by one of the standard analytical test procedures 
incorporated by reference and described in Tables Ia, Ib, Ic, Id, Ie, 
If, Ig, Ih, Ii, and Ij, or by any alternate test procedure which has 
been approved by the Administrator under the provisions of paragraph 
(d) of this section and Sec. Sec.  136.4 and 136.5. Under certain 
circumstances (paragraph (c) of this section, in Sec.  136.5(a) through 
(d) or 40 CFR 401.13) other additional or alternate test procedures may 
be used.
* * * * *

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    (b) The material listed in this paragraph (b) is incorporated by 
reference into this section with the approval of the Director of the 
Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. All approved 
incorporation by reference (IBR) material is available for inspection 
at the EPA and at the National Archives and Records Administration 
(NARA). Contact the EPA at: EPA's Water Docket, EPA West, 1301 
Constitution Avenue NW, Room 3334, Washington, DC 20004; phone: 202-
566-2426; email: [email protected]. For information on the 
availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected]. The 
material may be obtained from the following sources in this paragraph 
(b).
* * * * *
    (8) * * *
* * * * *
BILLING CODE 6560-50-C
    (xi) Method 1621, Determination of Adsorbable Organic Fluorine 
(AOF) in Aqueous Matrices by Combustion Ion Chromatography (CIC). EPA 
821-R-24-002. Table Ic.
    (xii) Method 1628 Method 1628 Polychlorinated Biphenyl (PCB) 
Congeners in Water, Soil, Sediment, Biosolids, and Tissue by Low-
resolution GC/MS using Selected Ion Monitoring. July 2021. EPA 821-R-
21-002. Table Ii.
    (xiii) Method 1633A Analysis of Per- and Polyfluoroalkyl Substances 
(PFAS) in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS. 
EPA-820-R-24-007. Table Ij.
* * * * *
    (10) American Public Health Association, 800 I Street, NW, 
Washington, DC 20001; phone: 202-777-2742; website: 
www.standardmethods.org.
    (i) Standard Methods for the Examination of Water and Wastewater. 
14th Edition, 1975. Table Ib, Notes 27 and 86.
    (ii) Standard Methods for the Examination of Water and Wastewater. 
15th Edition, 1980, Table Ib, Note 30; Table Id.
    (iii) Selected Analytical Methods Approved and Cited by the United 
States Environmental Protection Agency, Supplement to the 15th Edition 
of Standard Methods for the Examination of Water and Wastewater. 1981. 
Table Ic, Note 6; Table Id, Note 6.
    (iv) Standard Methods for the Examination of Water and Wastewater. 
18th Edition, 1992. Tables Ia, Ib, Ic, Id, Ie, and .
    (v) Standard Methods for the Examination of Water and Wastewater. 
19th Edition, 1995. Tables Ia, Ib, Ic, Id, Ie, and Ih.
    (vi) Standard Methods for the Examination of Water and Wastewater. 
20th Edition, 1998. Tables Ia, Ib, Ic, Id, Ie, and Ih.
    (vii) Standard Methods for the Examination of Water and Wastewater. 
21st Edition, 2005. Table Ib, Notes 17 and 27.
    (viii) 2120, Color. Revised September 4, 2021. Table Ib.
    (ix) 2130, Turbidity. Revised 2020. Table Ib.
    (x) 2310, Acidity. Revised 2020. Table Ib.
    (xi) 2320, Alkalinity. Revised 2021. Table Ib.
    (xii) 2340, Hardness. Revised 2021. Table Ib.
    (xiii) 2510, Conductivity. Revised 2021. Table Ib.
    (xiv) 2540, Solids. Revised 2020. Table Ib.
    (xv) 2550, Temperature. 2010. Table Ib.
    (xvi) 3111, Metals by Flame Atomic Absorption Spectrometry. Revised 
2019. Table Ib.
    (xvii) 3112, Metals by Cold-Vapor Atomic Absorption Spectrometry. 
Revised 2020. Table Ib.
    (xviii) 3113, Metals by Electrothermal Atomic Absorption 
Spectrometry. Revised 2020. Table Ib.
    (xix) 3114, Arsenic and Selenium by Hydride Generation/Atomic 
Absorption Spectrometry. Revised 2020, Table Ib.
    (xx) 3120, Metals by Plasma Emission Spectroscopy. Revised 2020. 
Table Ib.
    (xxi) 3125, Metals by Inductively Coupled Plasma-Mass Spectrometry. 
Revised 2020. Table Ib.
    (xxii) 3500-Ca, Calcium. Revised 2020. Table Ib.
    (xxiii) 3500-Cr, Chromium. Revised 2020. Table Ib.

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    (xxiv) 3500-K, Potassium. Revised 2020. Table Ib.
    (xxv) 3500-Na, Sodium. Revised 2020. Table Ib.
    (xxvi) 4110, Determination of Anions by Ion Chromatography. Revised 
2020. Table Ib.
    (xxvii) 4140, Inorganic Anions by Capillary Ion Electrophoresis. 
Revised 2020. Table Ib.
    (xxviii) 4500 Cl-, Chloride. Revised 2021. Table Ib.
    (xxix) 4500-Cl, Chlorine (Residual). 2011. Table Ib.
    (xxx) 4500-CN-, Cyanide. Revised 2021. Table Ib.
    (xxxi) 4500-F-, Fluoride. Revised 2021. Table Ib.
    (xxxii) 4500-H\+\, pH. 2021. Table Ib.
    (xxiii) 4500-H2O2 Hydrogen Peroxide (Residual) 2020. Table Ib.
    (xxxiv) 4500-NH3, Nitrogen (Ammonia). Revised 2021. 
Table Ib.
    (xxxv) 4500-NO2-, Nitrogen (Nitrite). Revised 
2021. Table Ib.
    (xxxvi) 4500-NO3-, Nitrogen (Nitrate). 
Revised 2019. Table Ib.
    (xxxvii) 4500-N(org), Nitrogen (Organic). Revised 2021. 
Table Ib.
    (xxxviii) 4500-O, Oxygen (Dissolved). Revised 2021. Table Ib.
    (xxxix) 4500-P, Phosphorus. Revised 2021. Table Ib.
    (xl) 4500-PAA Peracetic Acid (Residual) 2019. Table Ib.
    (xli) 4500-SiO2, Silica. Revised 2021. Table Ib.
    (xlii) 4500-S2-, Sulfide. Revised 2021. Table Ib.
    (xliii) 4500-SO32-, Sulfite. Revised 2021. 
Table Ib.
    (xliv) 4500-SO42-, Sulfate. Revised 2021. 
Table Ib.
    (xlv) 5210, Biochemical Oxygen Demand (BOD). Revised 2016. Table 
Ib.
    (xlvi) 5220, Chemical Oxygen Demand (COD). 2011. Table Ib.
    (xlvii) 5310, Total Organic Carbon (TOC). Revised 2014. Table Ib.
    (xlviii) 5520, Oil and Grease. Revised 2021. Table Ib.
    (xlix) 5530, Phenols. Revised 2021. Table Ib.
    (l) 5540, Surfactants. Revised 2021. Table Ib.
    (li) 6200, Volatile Organic Compounds. Revised 2020. Table Ic.
    (lii) 6410, Extractable Base/Neutrals and Acids. Revised 2020. 
Tables Ic and Id.
    (liii) 6420, Phenols. Revised 2021. Table Ic.
    (liv) 6440, Polynuclear Aromatic Hydrocarbons. Revised 2021. Table 
Ic.
    (lv) 6630, Organochlorine Pesticides. Revised 2021. Table Id.
    (lvi) 6640, Acidic Herbicide Compounds. Revised 2021. Table Id.
    (lvii) 7110, Gross Alpha and Gross Beta Radioactivity (Total, 
Suspended, and Dissolved). 2000. Table Ie.
    (lviii) 7500, Radium. 2001. Table Ie.
    (lix) 9213, Recreational Waters. 2007. Table Ih.
    (lxx) 9221, Multiple-Tube Fermentation Technique for Members of the 
Coliform Group. Approved 2014. Table Ia, Notes 12, 14; and 33; Table 
Ih, Notes 10, 12, and 32.
    (lxi) 9222, Membrane Filter Technique for Members of the Coliform 
Group. 2015. Table Ia, Note 31; Table Ih, Note 17.
    (lxii) 9223 Enzyme Substrate Coliform Test. 2016. Table Ia; Table 
Ih.
    (lxiii) 9230 Fecal Enterococcus/Streptococcus Groups. 2013. Table 
Ia, Note 32; Table Ih.
* * * * *
    (15) * * *
* * * * *
    (lxxi) ASTM D8421-24, Standard Test Method for Determination of 
Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous Matrices by Co-
solvation followed by Liquid Chromatography Tandem Mass Spectrometry 
(LC/MS/MS). June 2024. Table Ij.
* * * * *
    (38) * * *
    (i) Organochlorine Pesticides and PCBs in Wastewater Using EmporeTM 
Disk Test Method 3M 0222. Revised October 28, 1994. Table Id, Note 8.
* * * * *
    (e) * * *
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[FR Doc. 2024-29239 Filed 1-17-25; 8:45 am]
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