[Federal Register Volume 86, Number 100 (Wednesday, May 26, 2021)]
[Rules and Regulations]
[Pages 28277-28290]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-10974]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 141

[EPA-HQ-OW-2021-0079; FRL 10022-49-OW]


Expedited Approval of Alternative Test Procedures for the 
Analysis of Contaminants Under the Safe Drinking Water Act; Analysis 
and Sampling Procedures

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action announces the Environmental Protection Agency's 
(EPA) approval of alternative testing methods for use in measuring the 
levels of contaminants in drinking water to determine compliance with 
national primary drinking water regulations. The Safe Drinking Water 
Act authorizes EPA to approve the use of alternative testing methods 
through publication in the Federal Register. EPA is using this 
streamlined authority to make 17 additional methods available for 
analyzing drinking water samples. This expedited approach provides 
public water systems, laboratories, and primacy agencies with more 
timely access to new measurement techniques and greater flexibility in 
the selection of analytical methods, thereby reducing

[[Page 28278]]

monitoring costs while maintaining public health protection.

DATES: This action is effective May 26, 2021.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OW-2021-0079. All documents in the docket are listed on the 
https://www.regulations.gov website. Although listed in the index, some 
information is not publicly available, e.g., confidential business 
information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available 
electronically through https://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Glynda Smith, Technical Support 
Center, Standards and Risk Management Division, Office of Ground Water 
and Drinking Water (MS 140), Environmental Protection Agency, 26 West 
Martin Luther King Drive, Cincinnati, Ohio 45268; telephone number: 
(513) 569-7652; email address: [email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

    Public water systems are the regulated entities required to measure 
contaminants in drinking water samples. In addition, EPA Regions as 
well as State and Tribal governments with authority to administer the 
regulatory program for public water systems under the Safe Drinking 
Water Act (SDWA) may measure contaminants in water samples. When EPA 
sets a monitoring requirement in its national primary drinking water 
regulations for a given contaminant, the Agency also establishes (in 
the regulations) standardized test procedures for analysis of the 
contaminant. This action makes alternative testing methods available 
for particular drinking water contaminants beyond the testing methods 
currently established in the regulations. Drinking water systems, in 
consultation with the laboratories that support their compliance 
monitoring, may choose to use a test procedure established in the 
existing regulations, an alternative testing method that was approved 
in prior expedited approval actions, or an alternative method approved 
in this action. Categories and entities that may ultimately be affected 
by this action include:

------------------------------------------------------------------------
                                 Examples of potentially
            Category                regulated entities       NAICS \1\
------------------------------------------------------------------------
State, local, & tribal           State, local and tribal          924110
 governments.                     governments that
                                  analyze water samples
                                  on behalf of public
                                  water systems required
                                  to conduct such
                                  analysis; state, local
                                  and tribal governments
                                  that directly operate
                                  community and non-
                                  transient non-
                                  community water
                                  systems required to
                                  monitor.
Industry.......................  Private operators of             221310
                                  community and non-
                                  transient non-
                                  community water
                                  systems required to
                                  monitor.
Municipalities.................  Municipal operators of           924110
                                  community and non-
                                  transient non-
                                  community water
                                  systems required to
                                  monitor.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be interested in this 
action. Other types of entities not listed in the table could also have 
some interest. To determine whether your facility is affected by this 
action, you should carefully examine the applicability language in the 
Code of Federal Regulations (CFR) at 40 CFR 141.2 (definition of a 
public water system). 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.

Abbreviations and Acronyms Used in This Action

APHA: American Public Health Association
ATP: Alternate Test Procedure
CBI: Confidential Business Information
CFR: Code of Federal Regulations
DPASV: Differential Pulse Anodic Stripping Voltammetry
DPD: N,N-Diethyl-p-phenylenediamine
EPA: United States Environmental Protection Agency
GWR: Ground Water Rule
MCA: Monochloramine
MPN: Most probable number
NAICS: North American Industry Classification System
QC: Quality Control
RTCR: Revised Total Coliform Rule
SDWA: The Safe Drinking Water Act
SWTR: Surface Water Treatment Rule
SM: Standard Methods
VCSB: Voluntary Consensus Standard Bodies

II. Background

A. What is the purpose of this action?

    In this action, EPA is approving 17 analytical methods for 
determining contaminant concentrations in drinking water samples 
collected under SDWA. Regulated entities required to sample and monitor 
may use either the testing methods already established in existing 
regulations or the alternative testing methods being approved in this 
action or in prior expedited approval actions. The new methods are 
listed along with other methods similarly approved through previous 
expedited actions in the Code of Federal Regulations (CFR) at 40 CFR 
part 141, appendix A to subpart C and on EPA's drinking water methods 
website at https://www.epa.gov/dwanalyticalmethods.

B. What is the basis for this action?

    When EPA determines that an alternative analytical method is 
``equally effective'' (i.e., as effective as a method that has already 
been promulgated in the regulations), SDWA allows EPA to approve the 
use of the alternative testing method through publication in the 
Federal Register (see SDWA section 1401(1)). EPA is using this 
streamlined approval authority to make 17 additional methods available 
for determining contaminant concentrations in drinking water samples 
collected under SDWA. EPA has determined that, for each contaminant or 
group of contaminants listed in Section III of this document, the 
additional testing methods being approved in this action are as 
effective as one or more of the testing methods already approved in the 
regulations for those contaminants. Section 1401(1) of SDWA states that 
the newly approved methods ``shall be treated as an alternative for 
public water systems to the quality control and testing procedures 
listed in the regulation.'' Accordingly, this action makes these 
additional 17 analytical methods legally available as options for 
meeting EPA's monitoring requirements.
    This action does not add regulatory language, but does, for 
informational purposes, update an appendix to the regulations at 40 CFR 
part 141 that lists all methods approved under section

[[Page 28279]]

1401(1) of SDWA. Accordingly, while this action is not a rule, it is 
updating CFR text and therefore is being published in the ``Final 
Rules'' section of the Federal Register.

III. Summary of Approvals

    EPA is approving 17 methods that are equally effective relative to 
methods previously promulgated in the regulations. By means of this 
action, these 17 methods are added to appendix A to subpart C of 40 CFR 
part 141.

A. Methods Developed by EPA

    1. EPA Method 903.0, Revision 1.0. Alpha-Emitting Radium Isotopes 
in Drinking Water (USEPA 2021a). EPA Method 903.0 (USEPA 1980a) was 
published in the drinking water regulations at 40 CFR 141.25(a) as a 
screening method for radium-226. The approved method describes a 
single-point calibration, contains no quality control specifications, 
and provides no calculation for the drinking water detection limit. EPA 
Method 903.0, Revision 1.0 was developed in response to comments from 
stakeholders requesting a method revision that provides clearly defined 
calibration and quality control criteria to assure a more robust 
procedure capable of yielding consistent and reliable analytical 
results. The methodology relative to the approved method is unchanged. 
The importance of timing intervals is also discussed in the revised 
method. The primary interferences in radium-226 determination are due 
to activity contributed by radium-224 and, to a lesser degree, radium-
223. Due to their short half-lives, the interferences due to radium-224 
and radium-223 can be minimized if samples are held at least two weeks 
prior to counting.
    The revised method contains detailed instructions on preparing an 
appropriate calibration curve based on the allowable yield range 
instead of relying on a single-point calibration. Alpha particle 
response is sensitive to the level of solid residue left in the final 
precipitate. A single-point calibration assumes that every sample will 
yield the same mass of solid precipitate. Assessing the alpha 
efficiency based on a yield range will improve the accuracy in the 
final calculated activity.
    The revised method contains the quality control specifications that 
laboratories are expected to follow in order to obtain certification to 
analyze drinking water compliance samples. In addition to incorporation 
of specific quality control requirements and acceptance criteria, the 
revised method also allows the option to incorporate barium-133 as a 
radiochemical yield monitor. The currently approved method relies on 
gravimetric determination of the final barium sulfate precipitate to 
estimate the fractional yield of radium carried on the precipitate. 
Barium-133 is a non-interfering gamma emitter that is carried through 
the precipitation and complexation steps along with radium-226. 
Incorporation of a radiochemical yield monitor provides a sensitive 
option to assess yield based on activity instead of mass.
    The revised method contains an expanded ``calculations'' section 
that includes the appropriate equation for determining the drinking 
water detection limit as defined in the regulations at 40 CFR 
141.25(c).
    EPA has determined that EPA Method 903.0, Revision 1.0 is equally 
effective for screening drinking water samples for radium-226, relative 
to the approved method. The basis for this determination is discussed 
in greater detail in Smith 2020b. Therefore, EPA is approving EPA 
Method 903.0, Revision 1.0 for determining alpha-emitting radium 
isotopes in drinking water. EPA Method 903.0 Rev. 1.0 is available at 
the National Service Center for Environmental Publications.
    2. EPA Method 903.1, Revision 1.0. Radium-226 in Drinking Water 
Radon Emanation Technique (USEPA 2021b). EPA Method 903.1 (USEPA 1980b) 
was published in the drinking water regulations at 40 CFR 141.25(a) as 
a specific method for determination of radium-226. The approved method 
contains limited calibration information, no quality control 
specifications, no uncertainty calculation, and provides no calculation 
for the drinking water detection limit. As noted previously in the 
discussion about EPA Method 903.0, Rev. 1.0, EPA Method 903.1, Rev. 1.0 
was also developed in response to comments from stakeholders requesting 
a method revision with calibration and quality control criteria.
    The methodology in the revised method is unchanged and involves 
isolating the alpha-emitting radium isotopes through selective 
precipitation and complexation steps. Radon-222, the progeny of radium-
226, is allowed to ingrow and is then purged into an alpha 
scintillation cell for subsequent counting.
    The revised method contains the quality control specifications that 
laboratories are expected to follow in order to obtain certification to 
analyze drinking water compliance samples. In addition to incorporation 
of specific quality control requirements and acceptance criteria, the 
revised method provides additional options for assessing yield. The 
currently approved method specifies a barium sulfate precipitation step 
to estimate the fractional yield of radium carried on the precipitate. 
One option in the revised method allows the incorporation of barium-133 
as a radiochemical yield monitor. Barium-133 is a non-interfering gamma 
emitter that is carried through the procedure along with radium-226 and 
counted directly without requiring an additional precipitation step. 
Another option for determining yield on the radium-containing solution 
is to use atomic spectroscopy techniques.
    The revised method provides expanded uncertainty calculations based 
on the fact that each radon-222 atom yields three short-lived alpha-
emitting progeny. When half-life is short relative to the counting 
time, and detector efficiency is high, such as that obtained with alpha 
scintillation cells, there is an increased probability of observing a 
count not only from the parent, but also from the progeny.
    The revised method also contains an expanded ``calculations'' 
section that includes the equation for determining the drinking water 
detection limit as defined in the regulations at 40 CFR 141.25(c).
    EPA has determined that EPA Method 903.1, Revision 1.0 is equally 
effective for determining radium-226 in drinking water samples, 
relative to the approved method. The basis for this determination is 
discussed in greater detail in Smith 2020c. Therefore, EPA is approving 
EPA Method 903.1, Revision 1.0 for the determination of radium-226 in 
drinking water. EPA Method 903.1 Rev. 1.0 is available at the National 
Service Center for Environmental Publications.
    3. EPA Method 127. Determination of Monochloramine Concentration in 
Drinking Water (USEPA 2021c). The Surface Water Treatment Rule (SWTR) 
(USEPA 1989) specifies at 40 CFR 141.72(a)(4)(i) and at 40 CFR 
141.72(b)(3)(i) that water systems must maintain a detectable 
disinfectant residual in the distribution system. The disinfectant 
residual can be in the form of total chlorine, combined chlorine or 
chlorine dioxide. In addition, 40 CFR 141.72(a)(3) and 40 CFR 
141.74(b)(5) require that the residual disinfectant concentration in 
water entering the distribution system cannot fall below 0.2 mg/L for 
more than four hours. When the SWTR was promulgated, systems primarily 
relied on free chlorine as a secondary disinfectant to assure 
maintenance of a detectable residual in the distribution system. More 
systems have since switched to

[[Page 28280]]

the use of chloramination in order to reduce formation of regulated 
disinfection byproducts. Water systems have relied on measurement of 
chloramines using the total chlorine N,N-diphenylenediamine (DPD) 
colorimetric procedure described in Standard Method 4500-Cl G-00 (APHA 
2000), which is approved under the SWTR at 40 CFR 141.74(a)(2). Because 
the DPD reagent can react with a variety of other oxidants that may be 
present (e.g., organochloramines and manganese), this approach may 
result in an overestimation of the total chlorine residual. 
Organochloramines have little to no disinfection efficacy.
    Disinfection based on chloramination relies on producing 
monochloramine (MCA), dichloramine, and nitrogen trichloride. At 
typical drinking water distribution system pH levels (7-9), MCA 
predominates and is more effective and stable for disinfection than 
dichloramine or nitrogen trichloride. While no method was available for 
specific MCA measurement at the time the SWTR was promulgated, such 
capability now exists. EPA Method 127 was developed using commercially 
available reagents and instrumentation. Monochloramine in the presence 
of a cyanoferrate catalyst reacts with a substituted phenol to form an 
intermediate monoimine compound. The intermediate couples with excess 
substituted phenol to form a green-colored indophenol, which is 
proportional to the amount of monochloramine present in the sample. The 
indophenol can be measured using either a colorimeter or a 
spectrophotometer. It is not subject to the interferences observed with 
DPD determination and the technique is already used by water systems 
for (non-regulatory) process control monitoring or as part of a 
nitrification control plan. The method incorporates quality control 
specifications to assure robustness and performance.
    In addition to internal studies by EPA, two public water systems 
(PWSs) that employ chloramination for disinfection participated in 
method validation studies, comparing the performance of EPA Method 127 
to the performance of the approved DPD procedure. The validation study 
report (Alexander, Waters, and Wahman, 2020), summarizing the results 
from the PWSs' and EPA's studies, details the precision, accuracy, and 
sensitivity tests that were performed.
    EPA has determined that EPA Method 127 is equally effective 
relative to the approved method for determining total chlorine as 
monochloramine in finished drinking water. The basis for this 
determination is discussed in greater detail in Alexander 2021. 
Therefore, EPA is approving EPA Method 127 for the determination of 
total chlorine as monochloramine in assessing both minimum disinfection 
residual at the entry point to the distribution system and detectable 
disinfectant residual within the distribution system under the SWTR. 
EPA Method 127 is available at the National Service Center for 
Environmental Publications.

B. Methods Developed by Voluntary Consensus Standard Bodies (VCSB)

    1. ASTM International. EPA compared the most recent versions of 
eight ASTM International methods to the earlier versions of those 
methods that are currently approved in 40 CFR part 141. Most of the 
changes in the updated versions include additional quality control 
specifications.
    Changes between the earlier approved version and the most recent 
version of each method are described more fully in Smith (2020a). 
Besides additional quality control, the revisions involve primarily 
editorial changes (e.g., updated references, definitions, terminology, 
procedural clarifications, and reorganization of text). The revised 
methods are the same as the approved versions with respect to sample 
collection and handling protocols, sample preparation, analytical 
methodology, and method performance data; thus, EPA finds they are 
equally effective relative to the approved methods.
    EPA is thus approving the use of the following ASTM methods for the 
contaminants and their respective regulations listed in the following 
table:

----------------------------------------------------------------------------------------------------------------
       ASTM revised version           Approved method       Contaminant(s)            Regulation citations
----------------------------------------------------------------------------------------------------------------
D 6919-17 (ASTM 2017a)...........  D 6919-03 (ASTM       Calcium, Magnesium,   40 CFR 141.23(k)(1)
                                    2003a).               Sodium.
D 4327-17 (ASTM 2017b)...........  D4327-03 (ASTM        Fluoride, Nitrate,    40 CFR 141.23(k)(1)
                                    2003b).               Nitrite,             40 CFR 143.4(b)
                                                          Orthophosphate,
                                                          Chloride, Sulfate.
D 3697-17 (ASTM 2017c)...........  D 3697-02 (ASTM       Antimony............  40 CFR 141.23(k)(1)
                                    2002a).
D 3223-17 (ASTM 2017d)...........  D 3223-02 (ASTM       Mercury.............  40 CFR 141.23(k)(1)
                                    2002b).
D 1688 A-17 (ASTM 2017e).........  D 1688 A-02 (ASTM     Copper..............  40 CFR 141.23(k)(1)
                                    2002c).
D 1688 C-17 (ASTM 2017e).........  D 1688 C-02 (ASTM     Copper..............  40 CFR 141.23(k)(1)
                                    2002c).
D 1293-18 (ASTM 2018a)...........  D 1293-99 (ASTM       pH..................  40 CFR 141.23(k)(1)
                                    1999).
D 3454-18 (ASTM 2018b)...........  D 3454-97 (ASTM       Radium-226..........  40 CFR 141.25(a)
                                    1997).
----------------------------------------------------------------------------------------------------------------

    The ASTM methods are available from ASTM International, 100 Barr 
Harbor Drive, West Conshohocken, Pennsylvania 19428-2959 or http://www.astm.org.

C. Methods Developed by Vendors

    1. Bio-Rad. Simultaneous Detection of Total Coliform Bacteria and 
Escherichia coli Using RAPID'E. coli 2 (REC2) in Drinking Water (Bio-
Rad 2020). RAPID'E. coli 2 is a membrane-filter microbiological method 
for the simultaneous detection of total coliforms and E. coli in 
drinking water by filtration of a 100 mL sample of drinking water, and 
infusion of the filter with a growth and indicator medium during 
incubation. Total coliforms and E. coli are detected as being present 
or absent in 100 mL samples of drinking water by enzymatic cleavage of 
chromogenic substances with the formation of colored compounds after 
incubation. Drinking water methods approved for measuring total 
coliforms under the Revised Total Coliform Rule (RTCR) (USEPA 2013) are 
listed at 40 CFR 141.852(a)(5). Methods approved for measuring E. coli 
in drinking water under the RTCR and under the Ground Water Rule (GWR) 
(USEPA 2006) are listed at 40 CFR 141.402(c)(2) and 40 CFR 
141.852(a)(5), respectively. RAPID'E. coli 2 is similar to other 
approved drinking water methods but uses proprietary chromogens for 
detection of total coliforms and E. coli. These chromogens result in 
distinctive colors for colonies of target bacteria. RAPID'E. coli 2 is 
able to detect total coliforms and E. coli in 24  2 hours. 
Reagents for RAPID'E. coli 2 are available from the manufacturer. An 
Alternative Test Procedure (ATP) study was conducted to compare the 
method performance of RAPID'E. coli 2 to the performance of two 
approved methods, Standard Methods 9221 B (LTB/BGLB for total 
coliforms) and 9221 F (LTB/EC-MUG for E. coli) (APHA 1998). The

[[Page 28281]]

comparison study involved analyses of 200 drinking water samples--20 
replicate samples that were inoculated with very low densities of 
chlorine-stressed total coliforms or E. coli obtained from 10 
geographically dispersed waste waters. Method specificity was evaluated 
using an approximately 50:50 array of positive and negative cultures 
(as measured by RAPID'E. coli 2), transferring these cultures to the 
reference methods, and observing the reaction on the reference media. 
The ATP validation study report (Bio-Rad, 2019) details the study 
design and method data evaluation. EPA has determined that RAPID'E. 
coli 2 is equally effective relative to the approved Standard Method 
9221 B for total coliforms under the RTCR, and Standard Method 9221 F 
for E. coli under the RTCR and GWR. The basis for this determination is 
discussed in Sinclair (2019). Therefore, EPA is approving the RAPID'E. 
coli 2 method for determining total coliforms and E. coli in drinking 
water.
    A copy of the RAPID'E. coli 2 method is available from Bio-Rad 
Laboratories, 2000 Nobel Drive, Hercules, California 94547.
    2. Maine Health Environmental Testing Laboratory (HETL). ME 531, 
Version 1.0. Measurement of N-Methylcarbamoyloximes and N-
Methylcarbamates in Drinking Water by LC-MS/MS (Maine HETL 2019a). ME 
531 is a method for the measurement of carbofuran and oxamyl in 
drinking water by liquid chromatography tandem mass spectrometry (LC-
MS/MS). In this method, an aliquot from a preserved drinking water 
sample is injected into a LC system coupled to a triple quadrupole mass 
spectrometer. Chromatographic separation is achieved through use of an 
appropriate liquid chromatography analytical column and detection is 
achieved by operating a triple quadrupole mass spectrometer in MS/MS 
mode. Quantitation is determined by comparing measured response to a 
calibration curve generated with known analyte standards and the 
internal standard technique.
    Carbofuran and oxamyl are regulated drinking water contaminants as 
specified at 40 CFR 141.61(c). The currently approved methods for the 
analysis of carbofuran and oxamyl are listed in 40 CFR 141.24(e)(1). 
Approved methods EPA Method 531.1 (USEPA 1995) and EPA Method 531.2 
(USEPA 2001) use liquid chromatography and post-column derivatization 
to convert carbofuran and oxamyl to form highly fluorescent isoindoles, 
followed by fluorescence detection, which is sensitive but nonspecific. 
ME 531 reduces the amount of hazardous waste produced because it 
measures the contaminants directly without the need for derivatization. 
The method also increases efficiency of analysis time and provides more 
accurate results due to the higher sensitivity and specificity of LC-
MS/MS in the determination of carbofuran and oxamyl in finished 
drinking water.
    A laboratory validation study was conducted to evaluate the 
performance of ME 531. Multiple drinking water matrixes were used in 
the validation study. Precision, accuracy, and quantitation limit data 
were collected from the drinking water matrixes fortified with varying 
concentrations of carbofuran and oxamyl standards. The results are 
summarized in the validation study report (Maine HETL 2019b). EPA has 
determined that ME 531 is equally effective relative to the approved 
EPA Methods 531.1 and 531.2. The basis for this determination is 
discussed in Adams 2020a. Therefore, EPA is approving ME 531 for the 
analysis for carbofuran and oxamyl in drinking water. ME 531 can be 
obtained from Maine Health and Environmental Testing Lab, 221 State 
Street, Augusta, Maine 04330.
    3. Palintest. ChloroSense, Rev. 1.1. Free and Total Chlorine in 
Drinking Water by Amperometry using Disposable Sensors (Palintest 
2020a). ChloroSense, Rev. 1.1 is a method for the determination of free 
available and total chlorine, including hypochlorous acid, hypochlorite 
ion, and undissociated chlorine, in drinking water by amperometry using 
pre-calibrated disposable sensors. In this method, free available 
chlorine reacts with 3,3',5,5' tetramethylbenzidine (TMB) and the 
oxidized product is electrochemically reduced at the surface of the 
free chlorine electrode. Free available chlorine and combined chlorine 
react with potassium iodide (KI) to liberate iodine. The iodine can be 
reduced electrochemically at the surface of the total chlorine 
electrode. The current that flows in each case is proportional to the 
amount of free available chlorine or total available chlorine. The 
current is converted to mg Cl/L by reference to calibration parameters 
stored in the instrument software.
    The currently approved methods for the analysis of free and total 
chlorine in drinking water are listed in the regulations at 40 CFR 
141.131(c)(1) and at 40 CFR 141.74(a)(2). ChloroSense Rev. 1.0 
(Palintest 2009) was approved as being equally effective, relative to 
the approved Standard Method 4500-Cl D-00 (APHA 2000) for free and 
total chlorine, in the November 10, 2009 expedited methods approval 
action (USEPA 2009). ChloroSense, Rev. 1.1 is a modified version of 
ChloroSense, Rev. 1.0 that incorporates new hardware. The revision also 
clarifies language about method flexibility that was incorporated in 
Rev. 1.0. The modifications made for Rev. 1.1 did not include any 
changes to the analytical reagents or method chemistry.
    EPA reviewed the changes that were made and has determined that 
ChloroSense, Rev. 1.1 is equally effective relative to the previously 
approved ChloroSense, Rev. 1.0. The basis for this determination is 
discussed in Adams 2020b. Therefore, EPA is approving ChloroSense, Rev. 
1.1, for the analysis of free and total chlorine in drinking water. 
ChloroSense, Rev. 1.1, can be obtained from Palintest Ltd, 400 
Corporate Circle, Suite J, Golden, Colorado 80401.
    4. Palintest. Method 1001, Rev. 1.1. Lead in Drinking Water by 
Differential Pulse Anodic Stripping Voltammetry (Palintest 2020b). 
Method 1001, Rev. 1.1 is a method for the determination of total 
recoverable lead in drinking water using differential pulse anodic 
stripping voltammetry (DPASV). In this method, a 50-mL aliquot of acid-
preserved or acid-digested sample is neutralized with sodium hydroxide. 
A portion of the sample is decanted to a sample tube, buffered to pH 4, 
and conditioned with an excess of supporting electrolyte. A 
decomplexing agent is added to release lead from polyphosphate 
complexes. The lead in the conditioned sample is determined by DPASV, 
using a disposable sensor. This is achieved by concentrating the lead 
in the sample by plating onto the working electrode of the disposable 
sensor and then stripping it back into solution by raising the 
electrode potential. As the lead returns to solution a peak of current 
is detected. The peak potential identifies the metal, and the peak 
height is proportional to the concentration of the lead.
    The currently approved methods for the analysis of total 
recoverable lead in drinking water are listed in 40 CFR 141.23(k)(1). 
Method 1001, Rev. 1.1 revises the currently approved Method 1001 
(Palintest 1999) by allowing the use of new hardware, the streamlined 
Kemio instrumentation, which allows for the analysis of multiple 
contaminants. The modifications made for this method did not include 
any changes to the analytical reagents or method chemistry. Performance 
of Method 1001, Rev. 1.1. was compared with that of the approved Method 
1001. The Kemio instrumentation in Method 1001, Rev.1.1 had precision 
and

[[Page 28282]]

accuracy results comparable to those for instrumentation in the 
approved Method 1001. The Method Detection Limit (MDL) in the new 
method also improved from 2 [micro]g/L to 1 [micro]g/L using the Kemio 
instrumentation. EPA has determined that Method 1001, Rev. 1.1 is 
equally effective relative to the approved Method 1001. The basis for 
this determination is discussed in Adams 2020c. Therefore, EPA is 
approving Method 1001, Rev. 1.1 for the analysis of total recoverable 
lead in drinking water. Method 1001, Rev. 1.1 can be obtained from 
Palintest Ltd, 400 Corporate Circle, Suite J, Golden, Colorado 80401.
    5. Palintest. ChlordioX Plus, Rev. 1.1. Chlorine Dioxide and 
Chlorite in Drinking Water by Amperometry using Disposable Sensors 
(Palintest 2020c). ChlordioX Plus, Rev. 1.1 is a method for the 
determination of chlorine dioxide and chlorite in drinking water by 
amperometry using pre-calibrated disposable sensors. Chlorine dioxide 
present in the sample can be reduced directly at the surface of the 
sensor. The current that flows is directly proportional to the amount 
of chlorine dioxide in the sample. To determine chlorite, any chlorine 
dioxide in the sample must be removed. This is done by degassing the 
sample using a degassing unit. Chlorite is determined by first adding 
potassium iodide (KI) to the sample at a pH where the chlorite does not 
react but any free or total chlorine in the sample does react to 
liberate iodine. The amount of iodine released is reduced at the 
surface of the sensor. The current that flows is directly proportional 
to the amount of free and total chlorine in the sample (Reading A). The 
sample is then acidified by the addition of dilute hydrochloric acid. 
The iodide then reacts with chlorite and free and combined chlorine to 
release iodine. The amount of iodine released is reduced at the surface 
of the sensor. The current that flows is directly proportional to the 
amount of chlorite and free and combined chlorine in the sample 
(Reading B). The amount of chlorite can then be calculated by 
subtracting Reading A from Reading B. The current is converted to mg 
analyte/L by reference to calibration parameters stored in the 
instrument software.
    The currently approved methods for the analysis of chlorine dioxide 
in drinking water are listed at 40 CFR 141.131(c)(1) and at 40 CFR 
141.74(a)(2), and the approved methods for daily monitoring of chlorite 
are listed in 40 CFR 141.131(b)(1). ChlordioX Plus, Rev. 1.0 (Palintest 
2013) was approved as being equally effective, relative to the approved 
Standard Method 4500-ClO2 E (APHA 1998) for the analysis of 
chlorine dioxide and chlorite in drinking water, in the June 19, 2014 
expedited methods approval action (USEPA 2014). ChlordioX Plus, Rev. 
1.1 is a modified version of ChlordioX Plus, Rev. 1.0, which 
incorporates new hardware. The revision also clarifies language about 
method flexibility incorporated in the previous version. The 
modifications made for this method did not include any changes to the 
analytical reagents or method chemistry.
    EPA reviewed the changes that were made and has determined that 
ChlordioX Plus, Rev. 1.1 is equally as effective relative to the 
approved ChlordioX Plus, Rev. 1.0. The basis for this determination is 
discussed in Adams 2020d. Therefore, EPA is approving ChlordioX Plus, 
Rev. 1.1 for the analysis of chlorine dioxide and daily monitoring of 
chlorite in drinking water. ChlordioX Plus, Rev. 1.1 can be obtained 
from Palintest Ltd, 400 Corporate Circle, Suite J, Golden, Colorado 
80401.
    6. Neogen. Modified ColitagTM, Version 2.0. Modified 
ColitagTM Test Method for the Simultaneous Detection of 
Total Coliforms and E. coli in Water (Neogen 2020). Modified 
ColitagTM is a method that detects cleavage of chromogenic 
substrates to determine if total coliforms and E. coli are present in a 
100-mL drinking water sample within 16 to 48 hours of incubation. The 
method can be used in a most-probable-number (MPN) format, provided the 
sum of all the individual portions of the sample total 100 mL.
    Modified ColitagTM, Version 2.0 is an updated revision 
of Modified ColitagTM (CPI International 2009), which is 
approved for total coliforms and E. coli at 40 CFR 141.852(a)(5). 
Modified ColitagTM was approved in EPA's June 8, 2010 
expedited methods approval action (USEPA 2010) for determining E. coli 
under the Ground Water Rule at 40 CFR 141.402(c)(2).
    Modified ColitagTM, Version 2.0 provides expanded 
procedural guidance on the use of the various most-probable-number 
formats, including multiple tube MPN, the MPNPlateTM, and 
the MPNTrayTM options.
    EPA reviewed the revisions that were made and determined Modified 
ColitagTM, Version 2.0 is equally effective relative to the 
originally-approved Modified ColitagTM. The basis for this 
determination is discussed in Best 2020. Therefore, EPA is approving 
Modified ColitagTM, Version 2.0 for determination of total 
coliforms and E. coli in drinking water. Modified ColitagTM, 
Version 2.0 can be obtained from Neogen Corporation, 620 Lesher Place, 
Lansing, Michigan 48912.

IV. Statutory and Executive Order Reviews

    As noted in Section II of this action, under the terms of SDWA 
section 1401(1), this streamlined method approval action is not a rule. 
Accordingly, the Congressional Review Act, 5 U.S.C. 801 et seq., as 
added by the Small Business Regulatory Enforcement Fairness Act of 
1996, does not apply because this action is not a rule for purposes of 
5 U.S.C. 804(3). Similarly, this action is not subject to the 
Regulatory Flexibility Act because it is not subject to notice and 
comment requirements under the Administrative Procedure Act or any 
other statute. In addition, because this approval action is not a rule, 
but simply makes alternative testing methods available as options for 
monitoring under SDWA, EPA has concluded that other statutes and 
executive orders generally applicable to rulemaking do not apply to 
this approval action.

V. References

Adams, W. 2020a. Memo to the record describing basis for expedited 
approval of Maine Health Environmental Testing Laboratory ME 531, 
Version 1.0. July 2, 2020. (Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
Adams, W. 2020b. Memo to the record describing basis for expedited 
approval of Palintest ChloroSense, Rev. 1.1. July 9, 2020. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Adams, W. 2020c. Memo to the record describing the basis for 
expedited approval of Palintest Method 1001, Rev. 1.1. July 9, 2020. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Adams, W. 2020d. Memo to the record describing the basis for 
expedited approval of Palintest ChlordioX Plus, Rev. 1.1. July 9, 
2020. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
Alexander, M. 2021. Memo to the record describing basis for 
expedited approval of EPA Method 127. February 1, 2021. (Available 
at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
Alexander, M., Waters, T., and Wahman, D. 2020. Alternate Test 
Procedure Validation Study Report for EPA Method 127: Determination 
of Monochloramine in Drinking Water. June 2020. (Available at 
https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
American Public Health Association (APHA). 1998. 20th Edition of 
Standard Methods for the Examination of Water and Wastewater. 
American Public Health

[[Page 28283]]

Association, 800 I Street NW, Washington, DC 20001-3710.
American Public Health Association (APHA). Standard Method 4500-Cl 
D, G-00. Chlorine Residual. D. Amperometric Titration Method. G. DPD 
Colorimetric Method. Approved by Standard Methods Committee 2000. 
Standard Methods Online. (Available at http://www.standardmethods.org.)
ASTM International. 1997. ASTM D 3454-97. Standard Test Method for 
Radium-226 in Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 1999. ASTM D 1293-99. Standard Test Methods for 
pH of Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2002a. ASTM D 3697-02. Standard Test Method for 
Antimony in Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2002b. ASTM D 3223-02. Standard Test Method for 
Total Mercury in Water. ASTM International, 100 Barr Harbor Drive, 
West Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2002c. ASTM D 1688-02 A, C. Standard Test 
Methods for Copper in Water. A. Atomic Absorption, Direct. C. Atomic 
Absorption, Graphite Furnace. ASTM International, 100 Barr Harbor 
Drive, West Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2003a. ASTM D 6919-03. Standard Test Method for 
Determination of Dissolved Alkali and Alkaline Earth Cations and 
Ammonium in Water and Wastewater by Ion Chromatography. ASTM 
International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-
2959. (Available at http://www.astm.org.)
ASTM International. 2003b. ASTM D 4327-03. Standard Test Method for 
Anions in Water by Suppressed Ion Chromatography. ASTM 
International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-
2959. (Available at http://www.astm.org.)
ASTM International. 2017a. ASTM D 6919-17. Standard Test Method for 
Determination of Dissolved Alkali and Alkaline Earth Cations and 
Ammonium in Water and Wastewater by Ion Chromatography. ASTM 
International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-
2959. (Available at http://www.astm.org.)
ASTM International. 2017b. ASTM D 4327-17. Standard Test Method for 
Anions in Water by Suppressed Ion Chromatography. ASTM 
International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-
2959. (Available at http://www.astm.org.)
ASTM International. 2017c. ASTM D 3697-17. Standard Test Method for 
Antimony in Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2017d. ASTM D 3223-17. Standard Test Method for 
Total Mercury in Water. ASTM International, 100 Barr Harbor Drive, 
West Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2017e. ASTM D 1688-17 A, C. Standard Test 
Methods for Copper in Water. A. Atomic Absorption, Direct. C. Atomic 
Absorption, Graphite Furnace. ASTM International, 100 Barr Harbor 
Drive, West Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2018a. ASTM D 1293-18. Standard Test Methods for 
pH of Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
ASTM International. 2018b. ASTM 3454-18. Standard Test Method for 
Radium-226 in Water. ASTM International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959. (Available at http://www.astm.org.)
Best, J. 2020. Memo to the record describing basis for expedited 
approval of Neogen Modified ColitagTM, Version 2.0 
method. July 30, 2020. (Available at https://www.regulations.gov; 
docket ID No. EPA-HQ-OW-2021-0079.)
Bio-Rad. 2019. ATP Study Report for Side-By-Side Method Comparison 
of the Bio-Rad RAPID E. coli 2 Test Procedure and EPA Approved 
Reference Methods for Detection of Total Coliform Bacteria and E. 
coli in Drinking Water Using Membrane Filtration. September 4, 2019. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Bio-Rad. 2020. Simultaneous Detection of Total Coliform Bacteria and 
Escherichia coli Using RAPID'E. coli 2 (REC2) in Drinking Water. May 
2020. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
CPI International. 2009. Modified ColitagTM Test Method 
for the Simultaneous Detection of E. coli and other Total Coliforms 
in Water. August 2009. (Available at https://www.regulations.gov; 
docket ID No. EPA-HQ-OW-2021-0079.)
Maine Health Environmental Testing Laboratory. 2019a. ME 531, 
Version 1.0. Measurement of N-Methylcarbamoyloximes and N-
Methylcarbamates in Drinking Water by LC-MS/MS. September 2019. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Maine Health Environmental Testing Laboratory. 2019b. ME 531 
Validation Study Report. 2019. (Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
Neogen. 2020. Modified ColitagTM Test Method for the 
Simultaneous Detection of Total Coliforms and E. coli in Water. June 
2020. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
Palintest. 1999. Method 1001: Lead in Water by Differential Pulse 
Anodic Stripping Voltammetry. August 1999. (Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
Palintest. 2009. ChloroSense, Rev. 1.0. Measurement of Free and 
Total Chlorine in Drinking Water by Palintest ChloroSense. August 
2009. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
Palintest. 2013. ChordioX Plus, Rev. 1.0. Chlorine Dioxide and 
Chlorite in Drinking Water by Amperometry using Disposable Sensors. 
November 2013. (Available at https://www.regulations.gov; docket ID 
No. EPA-HQ-OW-2021-0079.)
Palintest. 2020a. ChloroSense, Rev. 1.1. Free and Total Chlorine in 
Drinking Water by Amperometry using Disposable Sensors. February 
2020. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
Palintest. 2020b. Method 1001, Rev. 1.1. Lead in Drinking Water by 
Differential Pulse Anodic Stripping Voltammetry. May 2020. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Palintest 2020c. ChlordioX Plus, Rev. 1.1. Chlorine Dioxide and 
Chlorite in Drinking Water by Amperometry using Disposable Sensors. 
February 2020. (Available at https://www.regulations.gov; docket ID 
No. EPA-HQ-OW-2021-0079.)
Sinclair, J. 2019. Memo to the record describing basis for expedited 
approval of Bio-Rad RAPID'E.coli 2 method. November 4, 2019. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Smith, G. 2020a. Memo to the record describing basis for expedited 
approval of updated methods from ASTM International. May 4, 2020. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
Smith, G. 2020b. Memo to the record describing basis for expedited 
approval of EPA Method 903.0, Revision 1.0. June 2, 2020. (Available 
at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
Smith, G. 2020c. Memo to the record describing basis for expedited 
approval of EPA Method 903.1. June 10, 2020. (Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-2021-0079.)
USEPA. 1980a. EPA Method 903.0. Alpha-emitting Radium Isotopes in 
Drinking Water in ``Prescribed Procedures for Measurement of 
Radioactivity in Drinking Water,'' EPA-600/4-80-032, August 1980. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
USEPA. 1980b. EPA Method 903.1. Radium-226 in Drinking Water Radon 
Emanation Technique in ``Prescribed Procedures for Measurement of 
Radioactivity in Drinking Water,'' EPA-600/4-80-032, August 1980. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)

[[Page 28284]]

USEPA. 1989. Drinking Water; National Primary Drinking Water 
Regulations; Filtration, Disinfection, Turbidity, Giardia lamblia, 
Viruses, Legionella, and Heterotrophic Bacteria. 54 FR 27486. June 
29, 1989. (Available at https://www.regulations.gov; docket ID No. 
EPA-HQ-OW-2021-0079.)
USEPA. 1995. EPA Method 531.1, Rev. 3.1. Measurement of N-
Methylcarbamoyloximes and N-Methylcarbamates in Water by Direct 
Aqueous Injection HPLC with Post Column Derivatization. 1995. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
USEPA. 2001. EPA Method 531.2, Rev. 1.0. Measurement of N-
Methylcarbamoyloximes and N-Methylcarbamates in Water by Direct 
Aqueous Injection HPLC with Post Column Derivatization. EPA-815-B-
01-002, September 2001. (Available at https://www.regulations.gov; 
docket ID No. EPA-HQ-OW-2021-0079.)
USEPA. 2006. National Primary Drinking Water Regulations: 
Groundwater Rule; Final Rule. 71 FR 65574. November 8, 2006. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079.)
USEPA. 2009. Expedited Approval of Alternative Test Procedures for 
the Analysis of Contaminants under the Safe Drinking Water Act; 
Analysis and Sampling Procedures; Final Rule. 74 FR 57908. November 
10, 2009. (Available at https://www.regulations.gov; docket ID No. 
EPA-HQ-OW-2021-0079.)
USEPA. 2010. Expedited Approval of Alternative Test Procedures for 
the Analysis of Contaminants under the Safe Drinking Water Act; 
Analysis and Sampling Procedures; Final Rule. 75 FR 32295. June 8, 
2010. (Available at https://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
USEPA. 2013. National Primary Drinking Water Regulations: Revisions 
to the Total Coliform Rule; Final Rule. 78 FR 10270. February 13, 
2013. (Available at http://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
USEPA. 2014. Expedited Approval of Alternative Test Procedures for 
the Analysis of Contaminants under the Safe Drinking Water Act; 
Analysis and Sampling Procedures; Final Rule. 79 FR 35081. June 19, 
2014. (Available at http://www.regulations.gov; docket ID No. EPA-
HQ-OW-2021-0079.)
USEPA. 2021a. EPA Method 903.0, Rev. 1.0. Alpha-emitting Radium 
Isotopes in Drinking Water. EPA 815-B-21-002. January 2021. 
(Available at https://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079 and at the National Service Center for Environmental 
Publications.)
USEPA. 2021b. EPA Method 903.1, Rev. 1.0. Radium-226 in Drinking 
Water Radon Emanation Technique. EPA 815-B-21-003. January 2021. 
(Available at http://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079 and at the National Service Center for Environmental 
Publications.)
USEPA. 2021c. EPA Method 127. Determination of Monochloramine 
Concentration in Drinking Water. EPA 815-B-21-004. January 2021. 
(Available at http://www.regulations.gov; docket ID No. EPA-HQ-OW-
2021-0079 and at the National Service Center for Environmental 
Publications.)

List of Subjects in 40 CFR Part 141

    Environmental protection, Chemicals, Indians-lands, 
Intergovernmental relations, Reporting and recordkeeping requirements, 
Water supply.

Jennifer L. McLain,
Director, Office of Ground Water and Drinking Water.
    For the reasons stated in the preamble, the Environmental 
Protection Agency amends 40 CFR part 141 as follows:

PART 141--NATIONAL PRIMARY DRINKING WATER REGULATIONS

0
1. The authority citation for part 141 continues to read as follows:

    Authority:  42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 
300g-5, 300g-6, 300j-4, 300j-9, and 300j-11.


0
2. Amend appendix A to subpart C of part 141 as follows:
0
a. In the table entitled ``ALTERNATIVE TESTING METHODS FOR CONTAMINANTS 
LISTED AT 40 CFR 141.23(k)(1)'' revising the entries for ``Antimony,'' 
``Calcium,'' ``Copper,'' ``Fluoride,'' ``Lead'', ``Magnesium,'' 
``Mercury,'' ``Nitrate,'' ``Nitrite,'' ``Orthophosphate,'' ``pH,'' and 
``Sodium'' ;
0
b. Revise the table entitled ``ALTERNATIVE TESTING METHODS FOR 
CONTAMINANTS LISTED AT 40 CFR 141.24(e)(1)'';
0
c. In the table entitled ``ALTERNATIVE TESTING METHODS FOR CONTAMINANTS 
LISTED AT 40 CFR 141.25(a)'' revise the entry for ``Radium 226'';
0
d. Revise the table entitled ``ALTERNATIVE TESTING METHODS FOR 
DISINFECTANT RESIDUALS LISTED AT 40 CFR 141.74(a)(2)'';
0
e. In the table entitled ``ALTERNATIVE TESTING METHODS FOR CONTAMINANTS 
LISTED AT 40 CFR 141.131(b)(1)'' revise the entry for ``Chlorite-daily 
monitoring as prescribed in 40 CFR 141.132(b)(2)(i)(A)'';
0
f. In the table entitled ``ALTERNATIVE TESTING METHODS FOR DISINFECTANT 
RESIDUALS LISTED AT 40 CFR 141.131(c)(1)'' revise the entries for 
``Free Chlorine,'' ``Total Chlorine,'' and ``Chlorine Dioxide'';
0
g. In the table entitled ``ALTERNATIVE TESTING METHODS FOR CONTAMINANTS 
LISTED AT 40 CFR 141.402(c)(2)'' revise the entry for ``E. coli'';
0
h. Revise the table entitled ``ALTERNATIVE TESTING METHODS FOR 
CONTAMINANTS LISTED AT 40 CFR 141.852(a)(5)'';
0
i. In the table entitled ``ALTERNATIVE TESTING METHODS FOR CONTAMINANTS 
LISTED AT 40 CFR 143.4(b)'' revise the entries for ``Chloride'' and 
``Sulfate'';
0
j. Revise footnotes ``2'', ``3'', ``4'', ``8'', ``9'', ``13'', ``14'', 
``16'', ``17'', ``24'', ``25'', ``26'', ``28'', ``29'', ``48'', and 
``49''; and,
0
k. Add footnotes 53 through 61.
    The revisions and additions read as follows:

Appendix A to Subpart C of Part 141--Alternative Testing Methods 
Approved for Analyses Under the Safe Drinking Water Act

* * * * *

                                                           Alternative Testing Methods for Contaminants Listed at 40 CFR 141.23 (k)(1)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       SM 21st          SM 22nd          SM 23rd
           Contaminant                   Methodology              EPA method         edition \1\      edition \28\     edition \49\    SM online \3\          ASTM \4\               Other
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                                          * * * * * * *
Antimony........................  Hydride--Atomic           .....................  ...............  ...............  ...............  ...............  D 3697-07, -12, -17..
                                   Absorption.
                                  Atomic Absorption;        .....................  3113 B.........  3113 B.........  3113 B.........  3113 B-04, B-10
                                   Furnace.
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
 
                                                                                          * * * * * * *
Calcium.........................  EDTA titrimetric........  .....................  3500-Ca B......  3500-Ca B......  3500-Ca B......  ...............  D 511-09, -14 A......
                                  Atomic Absorption;        .....................  3111 B.........  3111 B.........  3111 B.........  ...............  D 511-09, -14 B......
                                   Direct Aspiration.
                                  Inductively Coupled       .....................  3120 B.........  3120 B.........  3120 B.........
                                   Plasma.

[[Page 28285]]

 
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
                                  Ion Chromatography......  .....................  ...............  ...............  ...............  ...............  D 6919-09, -17.......
 
                                                                                          * * * * * * *
Copper..........................  Atomic Absorption;        .....................  3113 B.........  3113 B.........  3113 B.........  3113 B-04, B-10  D 1688-07, -12 C, -17
                                   Furnace.                                                                                                             C.
                                  Atomic Absorption;        .....................  3111 B.........  3111 B.........  3111 B.........  ...............  D 1688-07, -12 A, -17
                                   Direct Aspiration.                                                                                                   A.
                                  Inductively Coupled       .....................  3120 B.........  3120 B.........  3120 B.........
                                   Plasma.
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
                                  Colorimetry.............  .....................  ...............  ...............  ...............  ...............  .....................  Hach Method
                                                                                                                                                                               8026.\35\
                                                                                                                                                                              Hach Method 10272
                                                                                                                                                                               \36\
 
                                                                                          * * * * * * *
Fluoride........................  Ion Chromatography......  .....................  4110 B.........  4110 B.........  4110 B.........  ...............  D 4327-11, -17.......
                                  Manual Distillation;      .....................  4500-F- B, D...  4500-F- B, D...  4500-F- B, D...
                                   Colorimetric SPADNS.
                                  Manual Electrode........  .....................  4500-F- C......  4500-F- C......  4500-F- C......  ...............  D 1179-04, 10 B, 16 B
                                  Automated Alizarin......  .....................  4500-F- E......  4500-F- E......  4500-F- E......
                                  Arsenite-Free             .....................  ...............  ...............  ...............  ...............  .....................  Hach SPADNS. 2
                                   Colorimetric SPADNS.                                                                                                                        Method 10225.\22\
Lead............................  Atomic Absorption;        .....................  3113 B.........  3113 B.........  3113 B.........  3113 B-04, B-10  D 3559-08 D, -15 D...
                                   Furnace.
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
                                  Differential Pulse        .....................  ...............  ...............  ...............  ...............  .....................  Method 1001, Rev.
                                   Anodic Stripping                                                                                                                            1.1 \57\
                                   Voltametry.
Magnesium.......................  Atomic Absorption.......  .....................  3111 B.........  3111 B.........  3111 B.........  ...............  D 511-09, -14 B......
                                  Inductively Coupled       .....................  3120 B.........  3120 B.........  3120 B.........
                                   Plasma.
                                  Complexation Titrimetric  .....................  3500-Mg B......  3500-Mg B......  3500-Mg B......  ...............  D 511-09, -14 A......
                                   Methods.
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
                                  Ion Chromatography......  .....................  ...............  ...............  ...............  ...............  D 6919-09, -17.......
Mercury.........................  Manual, Cold Vapor......  .....................  3112 B.........  3112 B.........  3112 B.........  3112 B-09......  D 3223-12, -17.......
 
                                                                                          * * * * * * *
Nitrate.........................  Ion Chromatography......  .....................  4110 B.........  4110 B.........  4110 B.........  ...............  D 4327-11, -17.......
                                  Automated Cadmium         .....................  4500-NO3- F....  4500-NO3- F....  4500-NO3- F....
                                   Reduction.
                                  Manual Cadmium Reduction  .....................  4500-NO3- E....  4500-NO3- E....  4500-NO3- E....
                                  Ion Selective Electrode.  .....................  4500-NO3- D....  4500-NO3- D....  4500-NO3- D....
                                  Reduction/Colorimetric..  .....................  ...............  ...............  ...............  ...............  .....................  Systea Easy (1-
                                                                                                                                                                               Reagent).\8\
                                                                                                                                                                              NECi Nitrate-
                                                                                                                                                                               Reductase.\40\
                                  Colorimetric; Direct....  .....................  ...............  ...............  ...............  ...............  .....................  Hach TNTplus\TM\
                                                                                                                                                                               835/836 Method
                                                                                                                                                                               10206.\23\
                                  Capillary Ion             .....................  ...............  ...............  ...............  ...............  D 6508-15............
                                   Electrophoresis.
Nitrite.........................  Ion Chromatography......  .....................  4110 B.........  4110 B.........  4110 B.........  ...............  D 4327-11, -17.......
                                  Automated Cadmium         .....................  4500-NO3- F....  4500-NO3- F....  4500-NO3- F....
                                   Reduction.
                                  Manual Cadmium Reduction  .....................  4500-NO3- E....  4500-NO3- E....  4500-NO3- E....
                                  Spectrophotometric......  .....................  4500-NO2- B....  4500-NO2- B....  4500-NO2- B....
                                  Reduction/Colorimetric..  .....................  ...............  ...............  ...............  ...............  .....................  Systea Easy (1-
                                                                                                                                                                               Reagent).\8\
                                                                                                                                                                              NECi Nitrate-
                                                                                                                                                                               Reductase.\40\
                                  Capillary Ion             .....................  ...............  ...............  ...............  ...............  D 6508-15............
                                   Electrophoresis.
Ortho-phosphate.................  Ion Chromatography......  .....................  4110 B.........  4110 B.........  4110 B.........  ...............  D 4327-11, -17.......
                                  Colorimetric, ascorbic    .....................  4500-P E.......  4500-P E.......  4500-P E.......  4500-P E-99....
                                   acid, single reagent.
                                  Colorimetric, Automated,  .....................  4500-P F.......  4500-P F.......  4500-P F.......  4500-P F-99....  .....................  Thermo Fisher
                                   Ascorbic Acid.                                                                                                                              Discrete
                                                                                                                                                                               Analyzer.\41\
                                  Capillary Ion             .....................  ...............  ...............  ...............  ...............  D 6508-15............
                                   Electrophoresis.
pH..............................  Electrometric...........  150.3 \48\...........  4500-H + B.....  4500-H + B.....  4500-H + B.....  ...............  D 1293-12, -18.......
 
                                                                                          * * * * * * *
Sodium..........................  Atomic Absorption;        .....................  3111 B.........  3111 B.........  3111 B.........
                                   Direct Aspiration.
                                  Axially viewed            200.5, Revision 4.2
                                   inductively coupled       \2\.
                                   plasma-atomic emission
                                   spectrometry (AVICP-
                                   AES).
                                  Ion Chromatography......  .....................  ...............  ...............  ...............  ...............  D 6919-09, -17.......
 
                                                                                          * * * * * * *
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 28286]]


                                       Alternative Testing Methods for Contaminants Listed at 40 CFR 141.24(e)(1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        SM 22nd
                                                                                        SM 21st      edition \28\,
          Contaminant                    Methodology               EPA method         edition \1\       SM 23rd      SM online \3\          Other
                                                                                                     edition \49\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Benzene........................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Carbon tetrachloride...........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Chlorobenzene..................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,2-Dichlorobenzene............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,4-Dichlorobenzene............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,2-Dichloroethane.............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
cis-Dichloroethylene...........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
trans-Dichloroethylene.........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Dichloromethane................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,2-Dichloropropane............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Ethylbenzene...................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Styrene........................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Tetrachloroethylene............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,1,1-Trichloroethane..........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Trichloroethylene..............  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Toluene........................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,2,4-Trichlorobenzene.........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,1-Dichloroethylene...........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
1,1,2-Trichlorethane...........  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Vinyl chloride.................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
Xylenes (total)................  Purge & Trap/Gas             524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
2,4-D..........................  Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.
2,4,5-TP (Silvex)..............  Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.
                                 Solid Phase Extraction/Gas   ....................  525.3.\24\....
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Atrazine.......................  Liquid Chromatography        536.\25\............
                                  Electrospray Ionization
                                  Tandem Mass Spectrometry
                                  (LC/ESI-MS/MS).
                                 Solid Phase Extraction/Gas   525.3 \24\, 523.\26\
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Benzo(a)pyrene.................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Carbofuran.....................  High-performance liquid      ....................  6610 B........  6610 B........  6610 B-04.....
                                  chromatography (HPLC) with
                                  post-column derivatization
                                  and fluorescence detection.
                                 Liquid Chromatography/Mass   ....................  ..............  ..............  ..............  ME 531.\58\
                                  Spectrometry.
                                 Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Dalapon........................  Ion Chromatography           557.\14\............
                                  Electrospray Ionization
                                  Tandem Mass Spectrometry
                                  (IC-ESI-MS/MS).
                                 Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.
Di(2-ethylhexyl)adipate........  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Di(2-ethylhexyl)phthalate......  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Dibromochloropropane (DBCP)....  Purge &Trap/Gas              524.3.\9\...........
                                  Chromatography/Mass
                                  Spectrometry.
Dinoseb........................  Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.
Endrin.........................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Ethyl dibromide (EDB)..........  Purge &Trap/Gas              524.3.\9\...........
                                  Chromatography/Mass
                                  Spectrometry.
Glyphosate.....................  High-Performance Liquid      ....................  6651 B........  6651 B........  6651 B-00, B-
                                  Chromatography (HPLC) with                                                         05.
                                  Post-Column Derivatization
                                  and Fluorescence Detection.
Heptachlor.....................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Heptachlor Epoxide.............  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Hexachlorobenzene..............  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Hexachlorocyclo-pentadiene.....  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Lindane........................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Methoxychlor...................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Oxamyl.........................  High-performance liquid      ....................  6610 B........  6610 B........  6610 B-04.....
                                  chromatography (HPLC) with
                                  post-column derivatization
                                  and fluorescence detection.
                                 Liquid Chromatography/Mass   ....................  ..............  ..............  ..............  ME 531.\58\
                                  Spectrometry.
PCBs (as Aroclors).............  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Pentachlorophenol..............  Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.
                                 Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Picloram.......................  Gas Chromatography/Electron  ....................  6640 B........  6640 B........  6640 B-01, B-
                                  Capture Detection (GC/ECD).                                                        06.

[[Page 28287]]

 
Simazine.......................  Liquid Chromatography        536.\25\............
                                  Electrospray Ionization
                                  Tandem Mass Spectrometry
                                  (LC/ESI-MS/MS).
                                 Solid Phase Extraction/Gas   525.3 \24\, 523.\26\
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Toxaphene......................  Solid Phase Extraction/Gas   525.3.\24\..........
                                  Chromatography/Mass
                                  Spectrometry (GC/MS).
Total Trihalomethanes..........  Purge &Trap/Gas              524.3 \9\,
                                  Chromatography/Mass          524.4.\29\.
                                  Spectrometry.
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                             Alternative Testing Methods for Contaminants Listed at 40 CFR 141.25(a)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                 SM 22nd edition
            Contaminant                  Methodology                EPA method           SM 21st edition \1\      \28\, SM 23rd                ASTM \4\                    SM online \3\
                                                                                                                  edition \49\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                                          * * * * * * *
Radium 226........................  Radon emanation......  903.1, Rev. 1.0 \53\.......  7500-Ra C...........  7500-Ra C...........  D 3454-05, -18...............
                                    Radiochemical........  903.0, Rev. 1.0 \54\.......  7500-Ra B...........  7500-Ra B...........  D 2460-07....................
                                    Gamma Spectrometry...  ...........................  ....................  7500-Ra E...........  .............................  7500-Ra E-07.
 
                                                                                          * * * * * * *
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *

                                  Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.74(a)(2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             SM 22nd edition
            Residual                 Methodology         EPA methods      SM 21st edition     \28\, SM 23rd         ASTM \4\               Other
                                                                                \1\            edition \49\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Free Chlorine..................  Amperometric        ..................  4500-Cl D........  4500-Cl D........  D 1253-08, -14...
                                  Titration.
                                 DPD Ferrous         ..................  4500-Cl F........  4500-Cl F........
                                  Titrimetric.
                                 DPD Colorimetric..  ..................  4500-Cl G........  4500-Cl G........  .................  Hach Method 10260.\31\
                                 Indophenol          ..................  .................  .................  .................  Hach Method 10241.\34\
                                  Colorimetric.
                                 Syringaldazine      ..................  4500-Cl H........  4500-Cl H........
                                  (FACTS).
                                 On-line Chlorine    334.0 \16\........
                                  Analyzer.
                                 Amperometric        ..................  .................  .................  .................  ChloroSense \17\,
                                  Sensor.                                                                                          ChloroSense Rev.
                                                                                                                                   1.1.\59\
Total Chlorine.................  Amperometric        ..................  4500-Cl D........  4500-Cl D........  D 1253-08, -14...
                                  Titration.
                                 Amperometric        ..................  4500-Cl E........  4500-Cl E........
                                  Titration (Low
                                  level
                                  measurement).
                                 DPD Ferrous         ..................  4500-Cl F........  4500-Cl F........
                                  Titrimetric.
                                 DPD Colorimetric..  ..................  4500-Cl G........  4500-Cl G........  .................  Hach Method 10260.\31\
                                 Iodometric          ..................  4500-Cl I........  4500-Cl I........
                                  Electrode.
                                 On-line Chlorine    334.0 \16\........
                                  Analyzer.
                                 Amperometric        ..................  .................  .................  .................  ChloroSense \17\,
                                  Sensor.                                                                                          ChloroSense, Rev.
                                                                                                                                   1.1.\59\
                                 Indophenol          127.\55\..........
                                  Colorimetric.
Chlorine Dioxide...............  Amperometric        ..................  4500-ClO2 C......  4500-ClO2 C......
                                  Titration.
                                 Amperometric        ..................  4500-ClO2 E......  4500-ClO2 E......
                                  Titration.
                                 Amperometric        ..................  .................  .................  .................  ChlordioX Plus \32\,
                                  Sensor.                                                                                          ChlordioX Plus, Rev.
                                                                                                                                   1.1.\60\
Ozone..........................  Indigo Method.....  ..................  4500-O3 B........  4500-O3 B........
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                           Alternative Testing Methods for Contaminants Listed at 40 CFR 141.131(b)(1)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                              SM 22nd  edition
           Contaminant                 Methodology           EPA method            ASTM \4\          SM online \3\       SM 21st  edition      \28\, SM 23rd                  Other
                                                                                                                               \1\              Edition \49\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                                          * * * * * * *
Chlorite--daily monitoring as      Amperometric         ...................  ...................  ...................  4500-ClO2 E........  4500-ClO2 E........
 prescribed in 40 CFR               Titration.          ...................  ...................  ...................  ...................  ...................  ChlordioX Plus \32\, ChlordioX
 141.132(b)(2)(i)(A).              Amperometric Sensor                                                                                                            Plus, Rev. 1.1.\60\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 28288]]


                                  Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.131(c)(1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             SM 22nd edition,\28\ SM
           Residual                Methodology        SM 21st edition \1\       23rd edition \49\             ASTM \4\                   Other
--------------------------------------------------------------------------------------------------------------------------------------------------------
Free Chlorine.................  Amperometric       4500-Cl D...............  4500-Cl D..............  D 1253-08, -14.........
                                 Titration.
                                DPD Ferrous        4500-Cl F...............  4500-Cl F..............
                                 Titrimetric.
                                DPD Colorimetric.  4500-Cl G...............  4500-Cl G..............  .......................  Hach Method 10260.\31\
                                Indophenol         ........................  .......................  .......................  Hach Method 10241.\34\
                                 Colorimetric.
                                Syringaldazine     4500-Cl H...............  4500-Cl H..............
                                 (FACTS).
                                Amperometric       ........................  .......................  .......................  ChloroSense \17\,
                                 Sensor.                                                                                        ChloroSense, Rev.
                                                                                                                                1.1.\59\
                                On-line Chlorine   ........................  .......................  .......................  EPA 334.0.\16\
                                 Analyzer.
 
                                                                      * * * * * * *
Total Chlorine................  Amperometric       4500-Cl D...............  4500-Cl D..............  D 1253-08, -14.........
                                 Titration.
                                Low level          4500-Cl E...............  4500-Cl E..............
                                 Amperometric
                                 Titration.
                                DPD Ferrous        4500-Cl F...............  4500-Cl F..............
                                 Titrimetric.
                                DPD Colorimetric.  4500-Cl G...............  4500-Cl G..............  .......................  Hach Method 10260.\31\
                                Iodometric         4500-Cl I...............  4500-Cl I..............
                                 Electrode.
                                Amperometric       ........................  .......................  .......................  ChloroSense,\17\
                                 Sensor.                                                                                        ChloroSense, Rev.
                                                                                                                                1.1.\59\
                                On-line Chlorine   ........................  .......................  .......................  EPA 334.0.\16\
                                 Analyzer.
Chlorine Dioxide..............  Amperometric       4500-ClO2 E.............  4500-ClO2 E............
                                 Method II.
                                Amperometric       ........................  .......................  .......................  ChlordioX Plus,\32\
                                 Sensor.                                                                                        ChlordioX Plus, Rev.
                                                                                                                                1.1.\60\
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *

                                       Alternative Testing Methods for Contaminants Listed at 40 CFR 141.402(c)(2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    SM 20th        SM 21st        SM 22nd        SM 23rd
           Organism               Methodology     edition \6\    edition \1\    edition \28\  edition \49\     SM online \3\              Other
--------------------------------------------------------------------------------------------------------------------------------------------------------
E. coli......................  Colilert........  .............  9223 B.......  9223 B.......  9223 B......  9223 B-97, B-04...
                               Colisure........  .............  9223 B.......  9223 B.......  9223 B......  9223 B-97, B-04...
                               Colilert-18.....  9223 B.......  9223 B.......  9223 B.......  9223 B......  9223 B-97, B-04...
                               Readycult[supreg  .............  .............  .............  ............  ..................  Readycult[supreg].\20\
                                ].
                               Colitag.........  .............  .............  .............  ............  ..................  Modified ColitagTM \13\,
                                                                                                                                 Modified ColitagTM,
                                                                                                                                 Version 2.0.\61\
                               Chromocult[supre  .............  .............  .............  ............  ..................  Chromocult[supreg].\21\
                                g].
                               EC-MUG..........  .............  .............  9221 F.......  9221 F......  9221 F-06.........
                               NA-MUG..........  .............  .............  .............  9222 I......
                               m-ColiBlue24      .............  .............  .............  9222 J......
                                Test.
                               Tecta EC/TC33 43
                               RAPID'E.coli 2
                                \56\.
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *

                                       Alternative Testing Methods for Contaminants Listed at 40 CFR 141.852(a)(5)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Methodology                            SM 20th, 21st      SM 22nd  edition    SM 23rd  edition
            Organism                  category             Method            editions 1 6            \28\                \49\            SM online \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total Coliforms................  Lactose             Standard Total      ...................  9221 B.1, B.2.....  9221 B.1, B.2,      9221 B.1, B.2-06.
                                  Fermentation        Coliform                                                     B.3, B.4.
                                  Methods.            Fermentation
                                                      Technique.
                                                     Presence-Absence    ...................  ..................  9221 D.1, D.2, D.3  ..................
                                                      (P-A) Coliform
                                                      Test.
                                 Membrane            Standard Total      ...................  ..................  9222 B, C.          ..................
                                  Filtration          Coliform Membrane
                                  Methods.            Filter Procedure
                                                      using Endo Media.
                                                     Simultaneous        ...................  ..................  9222 J.             ..................
                                                      Detection of
                                                      Total Coliforms
                                                      and E. coli by
                                                      Dual Chromogen
                                                      Membrane Filter
                                                      Procedure (using
                                                      mColiBlue24
                                                      medium).

[[Page 28289]]

 
                                                     Simultaneous                                                                     ..................
                                                      Detection of
                                                      Total Coliform
                                                      Bacteria and
                                                      Escherichia coli
                                                      Using
                                                      RAPID'E.coli
                                                      (REC2) in
                                                      Drinking
                                                      Water.\56\
                                 Enzyme Substrate    Colilert[supreg]..  ...................  9223 B............  9223 B............  9223 B-04
                                  Methods.
                                                     Colisure[supreg]..  ...................  9223 B............  9223 B............  9223 B-04.
                                                     Colilert-18.......  9223 B.............  9223 B............  9223 B............  9223 B-04.
                                                     Tecta EC/TC.33 43.                                                               ..................
                                                     Modified                                                                         ..................
                                                      ColitagTM,
                                                      Version 2.0.\61\.
Escherichia coli...............  Escherichia coli    EC-MUG medium.....  ...................  9221 F.1..........  9221 F.1..........  9221 F.1-06.
                                  Procedure
                                  (following
                                  Lactose
                                  Fermentation
                                  Methods).
                                 Escherichia coli    EC broth with MUG   ...................  ..................  9222 H.             ..................
                                  Partitioning        (EC-MUG).
                                  Methods
                                  (following
                                  Membrane
                                  Filtration
                                  Methods).
                                                     NA-MUG medium.....  ...................  ..................  9222 I.             ..................
                                 Simultaneous        mColiBlue24 medium  ...................  ..................  9222 J.             ..................
                                  Detection of
                                  Total Coliforms
                                  and E. coli by
                                  Dual Chromogen
                                  Membrane Filter
                                  Procedure.
                                 Membrane            Simultaneous                                                                     ..................
                                  Filtration Method.  Detection of
                                                      Total Coliform
                                                      Bacteria and
                                                      Escherichia coli
                                                      Using
                                                      RAPID'E.coli
                                                      (REC2) in
                                                      Drinking
                                                      Water.\56\
                                 Enzyme Substrate    Colilert[supreg]..  ...................  9223 B............  9223 B............  9223 B-04.
                                  Methods.
                                                     Colisure[supreg]..  ...................  9223 B............  9223 B............  9223 B-04.
                                                     Colilert-18.......  9223 B.............  9223 B............  9223 B............  9223 B-04.
                                                     Tecta EC/TC.33 43                                                                ..................
                                                     Modified                                                                         ..................
                                                      ColitagTM,
                                                      Version 2.0.\61\.
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                         Alternative Testing Methods for Contaminants Listed at 40 CFR 143.4(b)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                           SM 22nd edition,\28\
     Contaminant         Methodology          EPA method             ASTM \4\         SM 21st edition \1\  SM 23rd edition \49\       SM online \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Chloride............  Silver Nitrate     ....................  D 512-04 B, 12 B....  4500-Cl- B..........  4500-Cl- B..........
                       Titration.
                      Ion                ....................  D 4327-11, -17......  4110 B..............  4110 B..............
                       Chromatography.
                      Potentiometric     ....................  ....................  4500-Cl- D..........  4500-Cl- D..........
                       Titration.
 
                                                                      * * * * * * *
Sulfate.............  Ion                ....................  D 4327-11, -17......  4110 B..............  4110 B..............
                       Chromatography.
                      Gravimetric with   ....................  ....................  4500-SO4 2 - C......  4500-SO4 2- C.......  4500-SO4 2- C-97.
                       ignition of
                       residue.
                      Gravimetric with   ....................  ....................  4500-SO4 2 - D......  4500-SO4 2- D.......  4500-SO4 2- D-97.
                       drying of
                       residue.
                      Turbidimetric      ....................  D 516-07, 11, 16....  4500-SO4 2- E.......  4500-SO4 2- E.......  4500-SO4 2- E-97.
                       method.
                      Automated          ....................  ....................  4500-SO4 2- F.......  4500-SO4 2- F.......  4500-SO4 2- F-97.
                       methylthymol
                       blue method.
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
 * * * * * * *
\1\ Standard Methods for the Examination of Water and Wastewater, 21st edition (2005). Available from American Public Health Association, 800 I Street
  NW, Washington, DC 20001-3710.
\2\ EPA Method 200.5, Revision 4.2. ``Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission
  Spectrometry.'' 2003. EPA/600/R-06/115. (Available at http://www.epa.gov/water-research/epa-drinking-water-research-methods.)
\3\ Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods
  Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.
\4\ Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 or http://astm.org. The methods listed are the only
  alternative versions that may be used.
 * * * * * * *
\6\ Standard Methods for the Examination of Water and Wastewater, 20th edition (1998). Available from American Public Health Association, 800 I Street
  NW, Washington, DC 20001-3710.
 * * * * * * *
\8\ Systea Easy (1-Reagent). ``Systea Easy (1-Reagent) Nitrate Method,'' February 4, 2009. Available at https://www.nemi.gov or from Systea Scientific,
  LLC., 900 Jorie Blvd., Suite 35, Oak Brook, IL 60523.
\9\ EPA Method 524.3, Version 1.0. ``Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry.''
  June 2009. EPA 815-B-09-009. Available at https://www.nemi.gov.
 * * * * * * *
\13\ Modified ColitagTM Method, ``Modified ColitagTM Test Method for the Simultaneous Detection of E. coli and other Total Coliforms in Water (ATP D05-
  0035),'' August 28, 2009. Available at https://www.nemi.gov or from CPI International, 5580 Skylane Boulevard, Santa Rosa, CA 95403.
\14\ EPA Method 557. ``Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem
  Mass Spectrometry (IC-ESI-MS/MS),'' September 2009. EPA 815-B-09-012. Available at https://www.nemi.gov.
 * * * * * * *
\16\ EPA Method 334.0. ``Determination of Residual Chlorine in Drinking Water Using an On-line Chlorine Analyzer,'' September 2009. EPA 815-B-09-013.
  Available at https://www.nemi.gov.
\17\ ChloroSense. ``Measurement of Free and Total Chlorine in Drinking Water by Palintest ChloroSense,'' August 2009. Available at https://www.nemi.gov
  or from Palintest Ltd, 1455 Jamike Avenue (Suite 100), Erlanger, KY 41018.

[[Page 28290]]

 
 * * * * * * *
\20\ Readycult[supreg] Method, ``Readycult[supreg] Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and
  Escherichia coli in Finished Waters,'' January, 2007. Version 1.1. Available from EMD Millipore (division of Merck KGaA, Darmstadt, Germany), 290
  Concord Road, Billerica, MA 01821.
\21\ Chromocult[supreg] Method, ``Chromocult[supreg] Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of
  Coliform Bacteria and Escherichia coli in Finished Waters,'' November, 2000. Version 1.0. EMD Millipore (division of Merck KGaA, Darmstadt, Germany),
  290 Concord Road, Billerica, MA 01821.
\22\ Hach Company. ``Hach Company SPADNS 2 (Arsenite-Free) Fluoride Method 10225--Spectrophotometric Measurement of Fluoride in Water and Wastewater,''
  January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539.
\23\ Hach Company. ``Hach Company TNTplus\TM\ 835/836 Nitrate Method 10206--Spectrophotometric Measurement of Nitrate in Water and Wastewater,'' January
  2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539.
\24\ EPA Method 525.3. ``Determination of Semivolatile Organic Chemicals in Drinking Water by and Capillary Column Gas Chromatography/Mass Spectrometry
  (GC/MS),'' February 2012. EPA/600/R-12/010. Available at http://www.epa.gov/water-research/epa-drinking-water-research-methods.
\25\ EPA Method 536. ``Determination of Triazine Pesticides and their Degradates in Drinking Water by Liquid Chromatography Electrospray Ionization
  Tandem Mass Spectrometry (LC/ESI-MS/MS).'' October 2007. EPA 815-B-07-002. Available at the National Service Center for Environmental Publications
  (EPA Method 536).
\26\ EPA Method 523. ``Determination of Triazine Pesticides and their Degradates in Drinking Water by Gas Chromatography/Mass Spectrometry (GC/MS).''
  February 2011. EPA 815-R-11-002. Available at the National Service Center for Environmental Publications (EPA Method 523).
 * * * * * * *
\28\ Standard Methods for the Examination of Water and Wastewater, 22nd edition (2012). Available from American Public Health Association, 800 I Street
  NW, Washington, DC 20001-3710.
\29\ EPA Method 524.4, Version 1.0. ``Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry using Nitrogen Purge
  Gas.'' May 2013. EPA 815-R-13-002. Available at the National Service Center for Environmental Publications (EPA Method 524.4).
 * * * * * * *
\31\ Hach Company. ``Hach Method 10260--Determination of Chlorinated Oxidants (Free and Total) in Water Using Disposable Planar Reagent-filled Cuvettes
  and Mesofluidic Channel Colorimetry,'' April 2013. 5600 Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.
\32\ ChlordioX Plus. ``Chlorine Dioxide and Chlorite in Drinking Water by Amperometry using Disposable Sensors,'' November 2013. Available from
  Palintest Ltd, 1455 Jamike Avenue (Suite 100), Erlanger, KY 41018.
\33\ Tecta EC/TC. ``Techta\TM\ EC/TC Medium and Techta\TM\ Instrument: A Presence/Absence Method for the Simultaneous Detection of Total Coliforms and
  Escherichia coli (E. coli) in Drinking Water,'' version 1.0, May 2014. Available from Pathogen Detection Systems, Inc., 382 King Street East,
  Kingston, Ontario, Canada, K7K 2Y2.
\34\ Hach Company. ``Hach Method 10241--Spectrophotometric Measurement of Free Chlorine (Cl2) in Drinking Water,'' November 2015. Revision 1.2. 5600
  Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.
\35\ Hach Company. ``Hach Method 8026--Spectrophotometric Measurement of Copper in Finished Drinking Water,'' December 2015. Revision 1.2. 5600
  Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.
\36\ Hach Company. ``Hach Method 10272--Spectrophotometric Measurement of Copper in Finished Drinking Water,'' December 2015. Revision 1.2. 5600
  Lindbergh Drive, P.O. Box 389, Loveland, CO 80539.
 * * * * * * *
\40\ Nitrate Elimination Company, Inc. (NECi). ``Method for Nitrate Reductase Nitrate-Nitrogen Analysis of Drinking Water,'' February 2016. Superior
  Enzymes, Inc., 334 Hecla Street, Lake Linden, Michigan 49945.
\41\ Thermo Fisher. ``Thermo Fisher Scientific Drinking Water Orthophosphate Method for Thermo Scientific Gallery Discrete Analyzer,'' February 2016.
  Revision 5. Thermo Fisher Scientific, Ratastie 2, 01620 Vantaa, Finland.
 * * * * * * *
\43\ Tecta EC/TC. ``TectaTM EC/TC Medium and the TectaTM Instrument: A Presence/Absence Method for the Simultaneous Detection of Total Coliforms and
  Escherichia coli (E. coli) in Drinking Water,'' version 2.0, February 2017. Available from Pathogen Detection Systems, Inc., 382 King Street East,
  Kingston, Ontario, Canada, K7K 2Y2.
 * * * * * * *
\48\ EPA Method 150.3. ``Determination of pH in Drinking Water,'' February 2017. EPA 815-B-17-001. Available at the National Service Center for
  Environmental Publications (EPA Method 150.3).
\49\ Standard Methods for the Examination of Water and Wastewater, 23rd edition (2017). Available from American Public Health Association, 800 I Street
  NW, Washington, DC 20001-3710.
 * * * * * * *
\53\ EPA Method 903.1, Rev. 1.0. ``Radium-226 in Drinking Water Radon Emanation Technique.'' January 2021. EPA 815-B-21-003. Available at the National
  Service Center for Environmental Publications (EPA Method 903.1).
\54\ EPA Method 903.0, Rev. 1.0. ``Alpha-Emitting Radium Isotopes in Drinking Water.'' January 2021. EPA 815-B-21-002. Available at the National Service
  Center for Environmental Publications (EPA Method 903.0).
\55\ EPA Method 127. ``Determination of Monochloramine Concentration in Drinking Water.'' January 2021. EPA 815-B-21-004. Available at the National
  Service Center for Environmental Publications (EPA Method 127).
\56\ Bio-Rad. ``Simultaneous Detection of Total Coliform Bacteria and Escherichia coli using RAPID'E. coli 2 (REC2) in Drinking Water.'' May 2020. Bio-
  Rad Laboratories, 2000 Nobel Drive, Hercules, California 94547.
\57\ Method 1001, Rev. 1.1. ``Lead in Drinking Water by Differential Pulse Anodic Stripping Voltammetry.'' May 2020. Palintest Ltd, 400 Corporate
  Circle, Suite J, Golden, CO 80401.
\58\ ME 531, Version 1.0. ``Measurement of N-Methylcarbamoyloximes and N-Methylcarbamates in Drinking Water by LC-MS/MS. September 2019. Maine Health
  Environmental Testing Laboratory, 221 State Street, Augusta, ME 04330.
\59\ ChloroSense, Rev. 1.1. ``Free and Total Chlorine in Drinking Water by Amperometry using Disposable Sensors.'' February 2020. Palintest Ltd, 400
  Corporate Circle, Suite J, Golden, CO 80401.
\60\ ChlordioX Plus, Rev. 1.1. ``Chlorine Dioxide and Chlorite in Drinking Water by Amperometry using Disposable Sensors.'' February 2020. Palintest
  Ltd, 400 Corporate Circle, Suite J, Golden, CO 80401.
\61\ Modified ColitagTM, Version 2.0. ``Modified ColitagTM Test Method for the Simultaneous Determination of Total Coliforms and E. coli in Water.''
  June 2020. Neogen Corporation, 620 Lesher Place, Lansing, MI 48912.

[FR Doc. 2021-10974 Filed 5-25-21; 8:45 am]
BILLING CODE 6560-50-P