[Federal Register Volume 81, Number 222 (Thursday, November 17, 2016)]
[Notices]
[Pages 81099-81114]
[FR Doc No: 2016-27667]

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OW-2012-0217; FRL-9955-27-OW]

Drinking Water Contaminant Candidate List 4--Final

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is publishing a
final list of contaminants that are currently not subject to any
proposed or promulgated national primary drinking water regulation.
These contaminants are known or anticipated to occur in public water
systems and may require regulation under the Safe Drinking Water Act
(SDWA). This list is the Fourth Contaminant Candidate List (CCL 4)
published by EPA since the SDWA amendments of 1996. This Final CCL 4
includes 97 chemicals or chemical groups and 12 microbial contaminants.

FOR FURTHER INFORMATION CONTACT: For information on chemical
contaminants contact Meredith Russell, Office of Ground Water and
Drinking Water, Standards and Risk Management Division, at (202) 564-
0814 or email<EMAIL_ADDRESS>For information on microbial
contaminants contact Hannah Holsinger, Office of Ground Water and
Drinking Water, Standards and Risk Management Division, at (202) 564-
0403 or email<EMAIL_ADDRESS>For general information contact
the EPA Safe Drinking Water Hotline at<PHONE_NUMBER>. The Safe
Drinking Water Hotline is open Monday through Friday, excluding legal
holidays, from 10 a.m. to 4 p.m. eastern time.

Abbreviations and Acronyms

CASRN--Chemical Abstract Services Registry Number
CCL--Contaminant Candidate List
CCL 1--EPA's First Contaminant Candidate List
CCL 2--EPA's Second Contaminant Candidate List
CCL 3--EPA's Third Contaminant Candidate List
CCL 4--EPA's Fourth Contaminant Candidate List
CFR--Code of Federal Regulations
CIS--Contaminant Information Sheet
DWC--Drinking Water Committee
EPA--United States Environmental Protection Agency
ESA--Ethanesulfonic acid
FR--Federal Register
HPC--Heterotrophic Plate Count
HRL--Health Reference Level
MCL--Maximum Contaminant Level
MCLG--Maximum Contaminant Level Goal
MRL-- Minimum Reporting Level
NAWQA--National Water-Quality Assessment
NDEA--N-Nitrosodiethylamine
NDMA--N-nitrosodimethylamine
NDPA--N-Nitroso-di-n-propylamine
NDPhA--N-Nitrosodiphenylamine
NDWAC--National Drinking Water Advisory Council
NIRS--National Inorganics and Radionuclides Survey
NRC--National Academy of Science's National Research Council
NPDWR--National Primary Drinking Water Regulation
NPYR--N-nitrosopyrrolidine
PCCL 4--Preliminary Contaminant Candidate List 4
PFOA--Perfluorooctanoic Acid
PFOS--Perfluorooctane Sulfonic Acid
PWS--Public Water System
RD--Regulatory Determination
RD 1--Regulatory Determination 1
RD 2--Regulatory Determination 2
RD 3--Regulatory Determination 3
SAB--Science Advisory Board
SDWA--Safe Drinking Water Act
SS--Screening Survey
TRI--Toxics Release Inventory
UCMR 1--First Unregulated Contaminant Monitoring Rule
UCMR 2--Second Unregulated Contaminant Monitoring Rule
UCMR 3--Third Unregulated Contaminant Monitoring Rule
USGS--United States Geological Survey
WBDO--Waterborne Disease Outbreaks

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
    A. Does this action apply to me?
    B. How can I get copies of this document and other related
information?
    1. Docket
    2. Electronic Access
    C. What is the purpose of this action?

    D. Statutory Requirements for CCL, Regulatory Determination and
Unregulated Contaminant Monitoring
    1. Interrelationship of the CCL, Regulatory Determination and
Unregulated Contaminant Monitoring
    2. Contaminant Candidate List
    3. Unregulated Contaminant Monitoring
    4. Regulatory Determinations
    E. Where can I find information on previous CCLs and Regulatory
Determinations?
    1. Summary of Previous CCLs and Regulatory Determinations
    2. Summary of the CCL 3
    3. Summary of the Regulatory Determination 3
II. What is on EPA's Drinking Water Contaminant Candidate List 4?
    The Final CCL 4 and a Cross-Walk of Contaminants Between the CCL
4, Regulatory Determination 3, and UCMRs
III. Summary of the Approach Used To Identify and Evaluate
Candidates for the Draft CCL 4
    A. Carry Forward of CCL 3 Contaminants
    B. Summary and Evaluation of CCL 4 nominated contaminants
    1. CCL 4 Nominations Summary
    2. How Nominated Contaminants Were Evaluated for the Draft CCL 4
    C. Evaluation of Previous Negative Regulatory Determinations
IV. What comments did EPA receive on the Draft CCL 4 and how did the
Agency respond?
    A. Recommendations From the EPA Science Advisory Board
    B. Public Comments
    1. General Comments on CCL 4
    2. Chemical Contaminants
    a. Contaminants With Release Data
    b. Cyanotoxins
    c. Perfluorinated Compounds (PFOA and PFOS)
    d. Pesticides
    e. Manganese
    f. Nonylphenol
    3. Microbial Contaminants
    a. Overall Process Comments
    b. Pathogens for Inclusion
    c. Pathogens for Exclusion
V. Data Needs for CCL 4 Contaminants
    Categorization of Contaminants
    A. Health Effects
    B. Occurrence
    C. Analytical Methods
VI. Next Steps and Future Contaminant Candidate Lists
VII. References

I. General Information

A. Does this action apply to me?

    The Final CCL 4 will not impose any requirements on anyone.
Instead, this action notifies interested parties of the EPA's Final CCL
4 of unregulated drinking water contaminants and provides a summary of
the major comments received on the February 4, 2015, Draft CCL 4
Federal Register notice and EPA's responses (80 FR 6076 (USEPA,
2015a)).

B. How can I get copies of this document and other related information?

1. Docket
    EPA has established a docket for this action under Docket ID No.
EPA-HQ-OW-2012-0217. Although listed in the index, some information is
not publicly available, e.g., CBI or other information whose disclosure
is restricted by statute. Certain other material, such as copyrighted
material, will be publicly available only in hard copy. Publicly
available docket materials are available either electronically through
www.regulations.gov or in hard copy at the Water Docket, EPA/DC, EPA
West, Room 3334, 1301 Constitution Ave. NW., Washington, DC 20004. The
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is<PHONE_NUMBER>, and the telephone number for the EPA
Docket Center is<PHONE_NUMBER>.
2. Electronic Access
    You may access this Federal Register document electronically from
the Government Publishing Office under the Federal Register listings at
FDsys (http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR).

C. What is the purpose of this action?

    The Safe Drinking Water Act (SDWA), as amended in 1996, requires
EPA to publish a list every five years of currently unregulated
contaminants that may pose risks for drinking water (referred to as the
Contaminant Candidate List, or CCL). This list is subsequently used to
make regulatory determinations on whether or not to regulate at least
five contaminants from the CCL with national primary drinking water
regulations (NPDWRs) ((SDWA section 1412(b)(1)). The purpose of today's
action is to present EPA's final list of contaminants on the CCL 4, a
summary of the major public comments received on the Draft CCL 4 and
EPA's responses. Today's action only addresses the Final CCL 4.
Regulatory Determination (RD) for contaminants on the CCL is a separate
agency action.

D. Statutory Requirements for CCL, Regulatory Determination and
Unregulated Contaminant Monitoring

1. Interrelationship of the CCL, Regulatory Determination and
Unregulated Contaminant Monitoring
    Under the 1996 amendments to SDWA, Congress established a risk-
based approach for determining which contaminants would become subject
to drinking water standards. The approach includes three components,
the CCL, the Unregulated Contaminant Monitoring Rule (UCMR), and RD. In
preparing the CCL, EPA screens and evaluates unregulated contaminants
to identify those that may require future drinking water regulations.
Inclusion on the CCL does not mean that any particular contaminant will
necessarily be regulated in the future. The UCMR provides a mechanism
to obtain nationally representative occurrence data for unregulated
contaminants. The data provided by UCMR is one of the primary sources
of occurrence information used to evaluate contaminants in the RD
process.
    Under the RD process, EPA evaluates UCMR and other occurrence data
along with health effects data for contaminants on the CCL to see which
ones present the greatest public health concern and have sufficient
information for the agency to make a regulatory determination. EPA must
make regulatory determinations for at least five contaminants listed on
the CCL every five years. Today's action addresses only the CCL 4 and
not the UCMR or RD stages of the SDWA contaminant regulatory
development process.
2. Contaminant Candidate List
    Section 1412(b)(1) of the SDWA, as amended in 1996, requires EPA to
publish the CCL every five years. The SDWA specifies that the list must
include contaminants that are not subject to any proposed or
promulgated NPDWRs, are known or anticipated to occur in public water
systems (PWSs), and may require regulation under the SDWA. The
unregulated contaminants considered for listing shall include, but not
be limited to, hazardous substances identified in section 101(14) of
the Comprehensive Environmental Response, Compensation, and Liability
Act of 1980, and substances registered as pesticides under the Federal
Insecticide, Fungicide, and Rodenticide Act.
    The SDWA directs the agency to consider the health effects and
occurrence information for unregulated contaminants to identify those
contaminants that present the greatest public health concern related to
exposure from drinking water. The statute further directs the agency to
take into consideration the effect of contaminants upon subgroups that
comprise a meaningful portion of the general population (such as
infants, children, pregnant women, the elderly and individuals with a
history of serious illness or other subpopulations) that are
identifiable as being at greater risk of

adverse health effects due to exposure to contaminants in drinking
water than the general population. Additionally, EPA's 1995 Policy on
Evaluating Health Risks to Children states that the agency will
consider the risks to infants and children consistently and explicitly
as a part of risk assessments generated during its decision-making
process, including the setting of standards to protect public health
(USEPA, 1995a). EPA considers age-related subgroups as ``lifestages''
in reference to a distinguishable time frame in an individual's life,
characterized by unique and relatively stable behavioral and/or
physiological characteristics that are associated with development and
growth. Thus, childhood is viewed as a sequence of lifestages, from
conception through fetal development, infancy and adolescence (see
http://www.epa.gov/children/early-life-stages).
3. Unregulated Contaminant Monitoring
    Section 1445(a)(2) of the SDWA mandates that EPA promulgate
regulations (known as the Unregulated Contaminant Monitoring Rule or
UCMR) to establish criteria for a monitoring program for unregulated
contaminants. This section, as amended in 1996, requires that once
every five years, EPA issue a list of no more than 30 unregulated
contaminants to be monitored by PWSs. SDWA requires that EPA enter the
monitoring data into the agency's publicly available National
Contaminant Occurrence Database. EPA's UCMR program must ensure that
systems serving a population larger than 10,000 people, as well as a
nationally representative sample of PWSs serving 10,000 or fewer
people, are required to monitor.
4. Regulatory Determination
    Section 1412(b)(1)(B)(ii) of the SDWA, as amended in 1996, requires
EPA at five year intervals, to make determinations of whether or not to
regulate no fewer than five contaminants from the CCL. EPA evaluates
the CCL contaminants with sufficient health effects and occurrence
information to determine whether a regulation is required or not
required. The 1996 SDWA Amendments specify three criteria to determine
whether a contaminant may require regulation:
     The contaminant may have an adverse effect on the health
of persons;
     the contaminant is known to occur or there is a
substantial likelihood that the contaminant will occur in PWSs with a
frequency and at levels of public health concern; and
     in the sole judgment of the Administrator, regulation of
such contaminant presents a meaningful opportunity for health risk
reduction for persons served by PWSs.
    If EPA determines that these three statutory criteria are met and
makes a final determination to regulate a contaminant, the agency has
24 months to publish a proposed maximum contaminant level goal \1\
(MCLG) and NPDWR.\2\ After the proposal, the agency has 18 months to
publish and promulgate a final MCLG and NPDWR (SDWA section
1412(b)(1)(E)).\3\ For those contaminants without sufficient
information to allow the agency to make a regulatory determination, EPA
encourages research to provide the information needed to determine
whether to regulate the contaminant.
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    \1\ The MCLG is the ``maximum level of a contaminant in drinking
water at which no known or anticipated adverse effect on the health
of persons would occur, and which allows an adequate margin of
safety. MCLGs are non-enforceable health goals.'' (40 CFR 141.2; 42
U.S.C. 300g-1)
    \2\ An NPDWR is a legally enforceable standard that applies to
public water systems. An NPDWR sets a legal limit (called a maximum
contaminant level or MCL) or specifies a certain treatment technique
for public water systems for a specific contaminant or group of
contaminants. The MCL is the highest level of a contaminant that is
allowed in drinking water and is set as close to the MCLG as
feasible, using the best available treatment technology and taking
cost into consideration.
    \3\ The statute authorizes a nine month extension of this
promulgation date.
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E. Where can I find information on previous CCLs, UCMRs, and Regulatory
Determinations

1. Summary of previous CCLs, UCMRs, and Regulatory Determinations
    A brief summary of CCL 1, CCL 2, Regulatory Determination 1 (RD 1)
and Regulatory Determination 2 (RD 2) was published in the Federal
Register for the Draft CCL 4 notice (80 FR 6076, February 4, 2015
(USEPA, 2015a)). Information on previous UCMRs, can be found at the
following Web site: https://www.epa.gov/dwucmr.
2. Summary of the CCL 3
    The CCL 3 included 104 chemicals or chemical groups and 12
microbiological contaminants. In developing the CCL 3, EPA implemented
an improved process from the process used for CCL 1 and CCL 2. This new
process built on evaluations used for previous CCLs and was based on
substantial expert input and recommendations from the National Academy
of Sciences' National Research Council (NRC) and the National Drinking
Water Advisory Council (NDWAC). EPA used a multi-step CCL process to
identify contaminants for inclusion on the Final CCL 3. The key steps
included:
     Identifying a broad universe of potential drinking water
contaminants (called the CCL 3 Universe). EPA initially considered
approximately 7,500 potential chemical and microbial contaminants (more
information on the identification of the CCL 3 Universe can be found in
USEPA, 2009a and USEPA, 2009b).
     Applying screening criteria to the universe, EPA
identified almost 600 of those contaminants that should be further
evaluated (the preliminary CCL or PCCL) based on a contaminant's
potential to occur in PWSs and the potential for public health concern
(more information on the CCL 3 screening process can be found in USEPA,
2009c and USEPA, 2009d).
     Selecting the final list of 116 contaminants from the PCCL
to include on the CCL based on more detailed evaluation of occurrence
and health effects and expert judgment as well as public input (this
step of the CCL 3 process is called the classification process and more
information can be found in USEPA, 2009e and USEPA, 2009f).
    The CCL 3 interpreted the criterion that contaminants are known or
anticipated to occur in public water systems broadly. In evaluating
this criterion, EPA considered not only public water system monitoring
data, but also data on concentrations in ambient surface and ground
waters, releases to the environment (e.g., Toxics Release Inventory
(TRI)), and production. While such data may not establish conclusively
that contaminants are known to occur in public water systems, EPA
believes these data are sufficient to anticipate that contaminants may
occur in public water systems and support their inclusion on the CCL.
The agency considered adverse health effects that may pose a greater
risk to life stages and other sensitive groups which represent a
meaningful portion of the population. Adverse health effects associated
with infants, children, pregnant women, the elderly, and individuals
with a history of serious illness were evaluated as part of the
screening and classification processes. A detailed summary of the CCL 3
process can be found in the Draft CCL 3 (73 FR 9628, February 21, 2008
(USEPA, 2008a) and Final CCL 3 (74 FR 51850, October 8, 2009 (USEPA,
2009a)) Federal Register notices.
3. Summary of the Regulatory Determination 3
    EPA published the Announcement of Final Regulatory Determinations
for Contaminants on CCL 3 in the Federal Register on January 4, 2016
(81 FR 13

(USEPA, 2016a)). The agency made final determinations not to regulate
four contaminants: 1, 3-dinitrobenzene; dimethoate; terbufos; and
terbufos sulfone. The agency delayed the final regulatory determination
for strontium in order to consider additional data and decide whether
there is a meaningful opportunity for health risk reduction by
regulating strontium in drinking water. These five contaminants are not
included on the Final CCL 4.
    This section provides an overview of the process used for the Third
Regulatory Determination (RD 3). A summary of the process can be found
in the Federal Register notice announcing the preliminary regulatory
determinations (79 FR 62716, October 24, 2014 (USEPA, 2014a)), and a
detailed explanation of this process can be found in the ``Protocol for
the Regulatory Determination 3'' support document (USEPA, 2014b). This
overview of the RD process is provided to give an understanding of how
contaminants have previously been evaluated after they have been listed
on past CCLs. The RD 4 process may continue to follow this process
although it is possible that some modifications may be made to this
process. The RD process occurs subsequent to a Final CCL, and is a
separate agency action. The RD 3 process, was divided into three
phases: (1) The Data Availability Phase, (2) the Data Evaluation Phase
and (3) the Regulatory Determination Assessment Phase.
    The purpose of the first phase, the Data Availability Phase, was to
determine if the agency may have sufficient data to characterize the
potential health effects and known or likely occurrence in drinking
water. With regard to sufficient health effects data used to identify
potential adverse health effect(s), the agency considered whether a
peer reviewed health risk assessment was available or in process from
an EPA or a comparable non-EPA source. In regard to sufficient
occurrence data, the agency considered the availability of nationally
representative finished water data and whether other finished water
data were available that indicated known and/or likely occurrence in
PWSs. After conducting the health and occurrence data availability
assessments, the agency identified those contaminants and contaminant
groups that meet the following Phase 1 data availability criteria:
    (a) A peer reviewed health assessment is available or in process,
and
    (b) A widely available analytical method for monitoring exists, and
    (c) Either nationally representative finished water occurrence data
are available, or other finished water occurrence data shows occurrence
at levels greater than one-half of the CCL 3 health reference level
(HRL).
    If a contaminant met these three criteria, it was placed on a
``short list'' and proceeded to Phase 2. From the 116 CCL 3
contaminants, the agency identified a short list of 37 contaminants (35
CCL 3 contaminants and two non-CCL 3 contaminants \4\) to further
evaluate in the second phase.
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    \4\ The non-CCL 3 contaminants, N-Nitroso-di-n-butylamine (NDBA)
and N-Nitrosomethylethylamine (NMEA), were included because they are
part of a larger group (nitrosamines) that also includes a number of
CCL 3 contaminants.
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    During the second phase, the Data Evaluation Phase, the agency
further evaluated each of the 37 contaminants on the short list to
identify those that had sufficient data (or were expected to have
sufficient data) for EPA to assess the three statutory criteria listed
in section I.D.4 of this notice.
    To identify the contaminants that present the greatest public
health concern, the agency specifically focused its efforts on
identifying those contaminants or contaminant groups that are occurring
or have substantial likelihood to occur at levels and frequencies of
public health concern, based on the best available peer reviewed data.
In addition to health and occurrence information data assessed in Phase
1, the agency collected additional health and occurrence data and more
thoroughly evaluated this information to identify a list of
contaminants that should proceed to Phase 3. If the agency found that
sufficient data were not available or not likely to be available to
evaluate the three statutory criteria during the first and second
phases, then the contaminant was not considered a candidate for making
a regulatory determination during the current cycle, and the agency
will conduct research, collect information or find other avenues to
fill the data and information gaps. For these contaminants, additional
data that becomes available in the future may be considered for future
CCLs and RDs.
    If sufficient data were available for a contaminant to characterize
the potential health effects and known or likely occurrence in drinking
water, the contaminant was evaluated against the three statutory
criteria (listed in section I.D.4) in the third phase of the process,
the Regulatory Determination Assessment Phase.

II. What is on EPA's Drinking Water Contaminant Candidate List 4?

The Final CCL 4 and a Cross-Walk of Contaminants Between the CCL 4,
Regulatory Determination 3, and UCMRs

    The Final CCL 4 includes 97 chemicals or chemical groups and 12
microbes listed in Exhibit 1. Exhibit 1 also shows chemical abstract
service registry numbers (CASRNs) of the contaminants on the Final CCL
4 and their status across other EPA programs related to CCL (i.e., RD
and UCMR). The list of contaminants is presented by CASRN when
available, common name, or by aggregate groupings (e.g., cyanotoxins).
Further data and information for the contaminants included on the CCL 4
are available in the technical support documents and Contaminant
Information Sheets available on EPA's CCL 4 Web site and in the docket
for this action (EPA-HQ-OW-2012-0217). All contaminants listed on the
Final CCL 4 were also included on CCL 3, with the exception of
manganese and nonylphenol, which were nominated by the public and added
to the CCL 4. Twenty-eight CCL 4 chemicals that were carried forward
from CCL 3 had been further analyzed and evaluated under the RD 3
process and included on the RD 3 Short List (further described in
section I.E.3. of this notice). The RD 3 process also included an
evaluation of occurrence data from the UCMR 2 for 13 CCL 4 chemicals.
Twenty-one CCL 4 contaminants were monitored under UCMR 3 (19 chemicals
and 2 microbes). The UCMR data will be used to further evaluate CCL 4
contaminants during the RD 4 process. In addition, EPA has proposed
gathering occurrence data for 16 individual CCL 4 chemicals and several
cyanotoxins, including anatoxin-a, cylindrospermopsin, nodularin, total
microcystin and several microcystin congeners under the proposed UCMR
4.

                       Exhibit 1--Contaminants on the Final CCL 4, Regulatory Determination 3, UCMR 2, UCMR 3 and Proposed UCMR 4
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                                                                          CCL 4                                                           Proposed  UCMR
                 CASRN                   Chemical or chemical group     nomination    RD 3 short list       UCMR 2           UCMR 3           4 \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
630-20-6...............................  1,1,1,2-Tetrachloroethane.  ...............               X   ...............  ...............  ...............
75-34-3................................  1,1-Dichloroethane........  ...............  ...............  ...............               X   ...............
96-18-4................................  1,2,3-Trichloropropane....  ...............               X   ...............               X   ...............
106-99-0...............................  1,3-Butadiene.............  ...............  ...............  ...............               X   ...............
123-91-1...............................  1,4-Dioxane...............  ...............               X   ...............               X   ...............
57-91-0................................  17 alpha-Estradiol........  ...............  ...............  ...............  ...............  ...............
71-36-3................................  1-Butanol.................  ...............  ...............  ...............  ...............               X
109-86-4...............................  2-Methoxyethanol..........  ...............  ...............  ...............  ...............               X
107-18-6...............................  2-Propen-1-ol.............  ...............  ...............  ...............  ...............               X
16655-82-6.............................  3-Hydroxycarbofuran.......  ...............  ...............  ...............  ...............  ...............
101-77-9...............................  4,4'-Methylenedianiline...  ...............  ...............  ...............  ...............  ...............
30560-19-1.............................  Acephate..................  ...............               X   ...............  ...............  ...............
75-07-0................................  Acetaldehyde..............  ...............  ...............  ...............  ...............  ...............
60-35-5................................  Acetamide.................  ...............  ...............  ...............  ...............  ...............
34256-82-1.............................  Acetochlor................  ...............               X                X   ...............  ...............
187022-11-3............................  Acetochlor ethanesulfonic   ...............               X                X   ...............  ...............
                                          acid (ESA).
194992-44-4............................  Acetochlor oxanilic acid    ...............               X                X   ...............  ...............
                                          (OA).
107-02-8...............................  Acrolein..................  ...............  ...............  ...............  ...............  ...............
142363-53-9............................  Alachlor ethanesulfonic     ...............               X                X   ...............  ...............
                                          acid (ESA).
171262-17-2............................  Alachlor oxanilic acid      ...............               X                X   ...............  ...............
                                          (OA).
319-84-6...............................  alpha-                                   X   ...............  ...............  ...............               X
                                          Hexachlorocyclohexane.
62-53-3................................  Aniline...................  ...............  ...............  ...............  ...............  ...............
741-58-2...............................  Bensulide.................  ...............  ...............  ...............  ...............  ...............
100-44-7...............................  Benzyl chloride...........  ...............  ...............  ...............  ...............  ...............
25013-16-5.............................  Butylated hydroxyanisole..  ...............  ...............  ...............  ...............               X
133-06-2...............................  Captan....................  ...............  ...............  ...............  ...............  ...............
14866-68-3.............................  Chlorate..................  ...............               X   ...............               X   ...............
74-87-3................................  Chloromethane (Methyl       ...............  ...............  ...............               X   ...............
                                          chloride).
110429-62-4............................  Clethodim.................  ...............  ...............  ...............  ...............  ...............
7440-48-4..............................  Cobalt....................  ...............               X   ...............               X   ...............
80-15-9................................  Cumene hydroperoxide......  ...............  ...............  ...............  ...............  ...............
N/A....................................  Cyanotoxins \a\...........               X   ...............  ...............  ...............               X
141-66-2...............................  Dicrotophos...............  ...............  ...............  ...............  ...............  ...............
55290-64-7.............................  Dimethipin................  ...............  ...............  ...............  ...............               X
330-54-1...............................  Diuron....................  ...............               X   ...............  ...............  ...............
517-09-9...............................  Equilenin.................  ...............  ...............  ...............  ...............  ...............
474-86-2...............................  Equilin...................  ...............  ...............  ...............               X   ...............
114-07-8...............................  Erythromycin..............  ...............  ...............  ...............  ...............  ...............
50-28-2................................  Estradiol (17-beta          ...............  ...............  ...............               X   ...............
                                          estradiol).
50-27-1................................  Estriol...................  ...............  ...............  ...............               X   ...............
53-16-7................................  Estrone...................  ...............  ...............  ...............               X   ...............
57-63-6................................  Ethinyl Estradiol (17-      ...............  ...............  ...............               X   ...............
                                          alpha ethynyl estradiol).
13194-48-4.............................  Ethoprop..................  ...............  ...............  ...............  ...............               X
107-21-1...............................  Ethylene glycol...........  ...............  ...............  ...............  ...............  ...............
75-21-8................................  Ethylene Oxide............  ...............  ...............  ...............  ...............  ...............
96-45-7................................  Ethylene thiourea.........  ...............  ...............  ...............  ...............  ...............
50-00-0................................  Formaldehyde..............  ...............  ...............  ...............  ...............  ...............
7440-56-4..............................  Germanium.................  ...............  ...............  ...............  ...............               X
74-97-5................................  Halon 1011                  ...............  ...............  ...............               X   ...............
                                          (bromochloromethane).
75-45-6................................  HCFC-22...................  ...............  ...............  ...............               X   ...............
110-54-3...............................  Hexane....................  ...............  ...............  ...............  ...............  ...............
302-01-2...............................  Hydrazine.................  ...............  ...............  ...............  ...............  ...............
7439-96-5..............................  Manganese.................               X   ...............  ...............  ...............               X
72-33-3................................  Mestranol.................  ...............  ...............  ...............  ...............  ...............
10265-92-6.............................  Methamidophos.............  ...............  ...............  ...............  ...............  ...............
67-56-1................................  Methanol..................  ...............  ...............  ...............  ...............  ...............
74-83-9................................  Methyl bromide              ...............               X   ...............               X   ...............
                                          (Bromomethane).
1634-04-4..............................  Methyl tert-butyl ether...               X                X   ...............  ...............  ...............
51218-45-2.............................  Metolachlor...............  ...............               X                X   ...............  ...............
171118-09-5............................  Metolachlor ethanesulfonic  ...............               X                X   ...............  ...............
                                          acid (ESA).
152019-73-3............................  Metolachlor oxanilic acid   ...............               X                X   ...............  ...............
                                          (OA).
7439-98-7..............................  Molybdenum................  ...............               X   ...............               X   ...............
98-95-3................................  Nitrobenzene..............  ...............               X   ...............  ...............  ...............
55-63-0................................  Nitroglycerin.............  ...............  ...............  ...............  ...............  ...............
872-50-4...............................  N-Methyl-2-pyrrolidone....  ...............  ...............  ...............  ...............  ...............
55-18-5................................  N-Nitrosodiethylamine       ...............               X                X   ...............  ...............
                                          (NDEA).
62-75-9................................  N-Nitrosodimethylamine      ...............               X                X   ...............  ...............
                                          (NDMA).
621-64-7...............................  N-Nitroso-di-n-propylamine  ...............               X                X   ...............  ...............
                                          (NDPA).
86-30-6................................  N-Nitrosodiphenylamine....  ...............               X   ...............  ...............  ...............

930-55-2...............................  N-Nitrosopyrrolidine        ...............               X                X   ...............  ...............
                                          (NPYR).
25154-52-3 \b\.........................  Nonylphenol...............               X   ...............  ...............  ...............  ...............
68-22-4................................  Norethindrone (19-          ...............  ...............  ...............  ...............  ...............
                                          Norethisterone).
103-65-1...............................  n-Propylbenzene...........  ...............  ...............  ...............  ...............  ...............
95-53-4................................  o-Toluidine...............  ...............  ...............  ...............  ...............               X
75-56-9................................  Oxirane, methyl-..........  ...............  ...............  ...............  ...............  ...............
301-12-2...............................  Oxydemeton-methyl.........  ...............  ...............  ...............  ...............  ...............
42874-03-3.............................  Oxyfluorfen...............  ...............  ...............  ...............  ...............               X
1763-23-1..............................  Perfluorooctane sulfonic    ...............               X   ...............               X   ...............
                                          acid (PFOS).
335-67-1...............................  Perfluorooctanoic acid                   X                X   ...............               X   ...............
                                          (PFOA).
52645-53-1.............................  Permethrin................               X   ...............  ...............  ...............               X
41198-08-7.............................  Profenofos................  ...............  ...............  ...............  ...............               X
91-22-5................................  Quinoline.................  ...............  ...............  ...............  ...............               X
121-82-4...............................  RDX.......................  ...............               X                X   ...............  ...............
135-98-8...............................  sec-Butylbenzene..........  ...............  ...............  ...............  ...............  ...............
107534-96-3............................  Tebuconazole..............  ...............  ...............  ...............  ...............               X
112410-23-8............................  Tebufenozide..............  ...............  ...............  ...............  ...............  ...............
13494-80-9.............................  Tellurium.................  ...............  ...............  ...............  ...............  ...............
59669-26-0.............................  Thiodicarb................  ...............  ...............  ...............  ...............  ...............
23564-05-8.............................  Thiophanate-methyl........  ...............  ...............  ...............  ...............  ...............
26471-62-5.............................  Toluene diisocyanate......  ...............  ...............  ...............  ...............  ...............
78-48-8................................  Tribufos..................  ...............  ...............  ...............  ...............               X
121-44-8...............................  Triethylamine.............  ...............  ...............  ...............  ...............  ...............
76-87-9................................  Triphenyltin hydroxide      ...............  ...............  ...............  ...............  ...............
                                          (TPTH).
51-79-6................................  Urethane..................  ...............  ...............  ...............  ...............  ...............
7440-62-2..............................  Vanadium..................  ...............               X   ...............               X   ...............
50471-44-8.............................  Vinclozolin...............  ...............  ...............  ...............  ...............  ...............
137-30-4...............................  Ziram.....................  ...............  ...............  ...............  ...............  ...............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Anatoxin-a, cylindrospermopsin, nodularin, total microcystin and several microcystin congeners are proposed for monitoring under UCMR 4.
\b\ The organization that nominated ``nonylphenol'' for CCL 4 provided the CASRN of 25451-52-3. The name ``nonylphenol'' does not allow for a definitive
  identification of chemical structure since nonylphenol can exhibit two forms of isomerism. There are at least five CASRNs known to be associated with
  ``nonylphenol'': In addition to 25154-52-3 (which represents n-nonylphenol with the ortho-, meta-, or para-substitution unspecified), other CASRNs
  include: 104-40-5 (4-n-nonylphenol); 84852-15-3 (4-nonylphenol, branched); 91672-41-2 (2-nonylphenol, branched); and 139-84-4 (3-n-nonylphenol). None
  of these five CASRNs is adequately general enough to represent both forms of isomerism. For the sake of consistency, the CASRN provided by the
  nominator was selected and the additional possible CASRNs and structures are delineated here.

------------------------------------------------------------------------
                                             CCL 4
               Microbe *                   nomination         UCMR 3
------------------------------------------------------------------------
Adenovirus............................               X   ...............
Caliciviruses.........................  ...............               X
Campylobacter jejuni..................  ...............  ...............
Enterovirus...........................  ...............               X
Escherichia coli (O157)...............  ...............  ...............
Helicobacter pylori...................  ...............  ...............
Hepatitis A virus.....................  ...............  ...............
Legionella pneumophila................  ...............  ...............
Mycobacterium avium...................  ...............  ...............
Naegleria fowleri.....................               X   ...............
Salmonella enterica...................  ...............  ...............
Shigella sonnei.......................  ...............  ...............
------------------------------------------------------------------------
* There were no CCL 4 microbes monitored under UCMR 2, and none are
  proposed for monitoring under UCMR 4. The UCMR 4 Candidate
  Contaminants Information Compendium (USEPA, 2015b) provides a
  rationale for why contaminants, including microbes, were not included
  in the proposed UCMR 4. No CCL 4 microbes were included in the RD 3
  Short List. Norovirus, a member of the calicivirus family, was
  included on UCMR 3 pre-screen testing.

III. Summary of the Approach Used To Identify and Evaluate Candidates
for the Draft CCL 4

    The Draft CCL 4 was published in the Federal Register on February
4, 2015 (80 FR 6076 (USEPA, 2015a)). EPA used a three step evaluation
and selection process to identify candidates for the Draft CCL 4: (1)
Carry forward CCL 3 contaminants (except those with regulatory
determinations), (2) seek and evaluate nominations from the public for
additional contaminants to consider, (3) evaluate any new data for
those contaminants with previous negative regulatory determinations
from CCL 1 or CCL 2 for potential inclusion on the CCL 4. The CCL 3
process is summarized in section I.E.2. A brief summary of steps 1-3
that were used to develop the Draft CCL 4 is provided in the section
that follows, and a more detailed summary is provided in the Draft CCL
4 Federal Register notice (80 FR 6076 (USEPA, 2015a)). A summary of the
public comments on the Draft CCL 4 and EPA's responses can be found in
section IV.

A. Carry Forward of CCL 3 Contaminants to the Draft CCL 4

    EPA carried forward all contaminants listed on CCL 3 to the Draft
CCL 4 with the exception of perchlorate, for which the agency made a
positive regulatory determination, and the five CCL 3 contaminants with
preliminary regulatory determinations at that time, pending their final
regulatory determinations. This carry forward process is consistent
with that previously used in CCL 2. The agency took this approach based
on the following considerations: (1) In developing the CCL 3, the
agency implemented a robust process recommended by the NRC and the
NDWAC to screen and score the universe of potential contaminants; (2)
EPA used the best available, peer reviewed data and information to
evaluate contaminants for CCL 3; and (3) Carrying forward CCL 3
contaminants allowed the agency to focus resources on evaluating
contaminants nominated by the public for CCL 4 and review new data for
CCL 1 or CCL 2 contaminants with previous negative regulatory
determinations (68 FR 42897, July 18, 2003 (USEPA, 2003); 73 FR 44251,
July 30, 2008 (USEPA, 2008b)). Carrying forward CCL 3 contaminants also
allowed EPA to focus resources on UCMR 3 monitoring and analysis and RD
3 analyses.

B. Summary and Evaluation of CCL 4 Nominated Contaminants

1. CCL 4 Nominations Summary
    EPA sought public nominations in a Federal Register notice on May
8, 2012 (77 FR 27057), for contaminants to be considered for possible
inclusion in the CCL 4 (USEPA, 2012)). EPA received nominations for 59
unique contaminants for the CCL 4, including 54 chemical and five
microbial contaminants. After carefully reviewing and evaluating the
information and data for the nominated contaminants, EPA added two of
the nominated chemicals (manganese and nonylphenol) to the Draft CCL 4.
Detailed information on the nominations is contained in the ``Summary
of Nominations for the Fourth Contaminant Candidate List'' support
document (USEPA, 2016b).
2. How Nominated Contaminants Were Evaluated for the Draft CCL 4
    Four nominated contaminants were already covered by a proposed or
existing NPDWR and were not eligible for the CCL 4 since the SDWA
specifies that the CCL only include those contaminants without any
proposed or promulgated NPDWRs. Seven of the nominated contaminants
were on CCL 3 and were carried forward to the Draft CCL 4. EPA reviewed
the nominations and supporting information to determine if any new data
were provided that had not been previously evaluated for CCL 3. The
agency also collected and evaluated additional data for the nominated
contaminants, when it was available, including the seven nominated
contaminants carried forward from CCL 3. The additional data was
obtained from both updated CCL 3 data sources and from new data sources
that were not available at the time the agency finalized CCL 3. These
data sources are listed in the ``Data Sources for the Contaminant
Candidate List 4'' support document (USEPA, 2016c).
    Nominated contaminants with new data were screened and scored using
the same process used in CCL 3. Through this analysis, EPA added
manganese and nonylphenol to the Draft CCL 4 because, as discussed in
more detail in the Draft CCL 4 Federal Register notice (80 FR 6076
(USEPA, 2015a)), EPA determined that the new and updated health effects
information and additional occurrence data merited listing the
contaminants. Detailed information on the data used to screen the
nominated contaminants to determine whether or not they were included
in the PCCL 4 is available in the ``Screening Document for the PCCL 4
Nominated Contaminants'' (USEPA, 2016d). More detailed information on
the process and the data used to evaluate nominated contaminants for
listing on the CCL 4 can be found in the ``Contaminants Information
Sheets (CISs) for the Final Contaminant Candidate List 4 (CCL 4)''
support documents (USEPA, 2016e).

C. Evaluation of Previous Negative Regulatory Determinations for the
Draft CCL 4

    EPA evaluated the 20 contaminants from CCL 1 and CCL 2 for which
the agency made negative regulatory determinations. EPA collected and
evaluated new or updated data for the previous negative regulatory
determination chemicals. Since RD 3 was recently published using the
best available data, EPA did not include the RD 3 negative regulatory
determinations in this evaluation. The agency concluded there was not
sufficient new information for 19 of the 20 contaminants with previous
negative regulatory determinations to justify including them on the
Draft CCL 4. Because commenters also did not identify such information,
EPA has not included these contaminants on the Final CCL 4. EPA added
manganese, a previous negative regulatory determination from RD 1, to
the Draft and Final CCL 4 as previously discussed in section III.B.

IV. What comments did EPA receive on the Draft CCL 4 and how did the
Agency respond?

    EPA requested comment on the Draft CCL 4 and how to further improve
upon the selection process developed for CCL 3 as a tool for future
CCLs. The agency received 27 public comment letters on the Draft CCL 4.
EPA considered all public comments and evaluated the data and
information provided by commenters in selecting the Final CCL 4. EPA
used the same process used in the CCL 3 to screen and score any
contaminants with new data or information provided by commenters. EPA
prepared responses to all public comments that are in the ``Comment
Response Document for the Fourth Drinking Water Contaminant Candidate
List (Categorized Public Comments)'' document, which is available in
the docket for this action (USEPA, 2016f).
    Based on the analyses conducted as a result of public comments, EPA
determined not to list three cancelled pesticides (disulfoton,
fenamiphos, and molinate) on the Final CCL 4 that were included on the
Draft CCL 4 because, as discussed more fully in the following sections,
these chemicals are not known or anticipated to occur in PWSs and are
not anticipated to require regulation. With the exception of these
three pesticides, all of the contaminants listed on the Draft CCL 4 are
listed on the Final CCL 4.
    A summary of some of the key public comments received,
recommendations from EPA's Science Advisory Board (SAB) on the CCL 4,
and EPA's responses are provided in this section. Data used to evaluate
the contaminants for the CCL 4 can be found in the Contaminant
Information Sheets (CISs) for the Final Fourth Contaminant Candidate
List (CCL 4) (USEPA, 2016e), which can be found in the docket for this
action available at www.regulations.gov by searching for docket EPA-HQ-
OW-2012-0217.

A. Recommendations From the EPA Science Advisory Board

    The EPA SAB and its Drinking Water Committee (DWC) reviewed the
Draft CCL 4 and provided recommendations to the Administrator on
January 11, 2016, in their report ``Review of the EPA's Draft Fourth
Drinking Water Contaminant Candidate List (CCL 4)'' (USEPA, 2016g). On
April 29-30, 2015, the SAB DWC held a public meeting to discuss
responses to EPA charge

questions. During this meeting, EPA provided an overview of the process
used to develop the Draft CCL 4 and answered questions from the
Committee.
    The SAB's recommendations and comments on the overall CCL 4 process
and documentation are summarized in the following bullet points:
     The SAB stated that the general protocol used to evaluate
contaminants on the CCL 4 is well described and conceptually clear.
They concluded the transparency and clarity of the process has improved
since CCL 3 was finalized.
     The SAB said that the documentation for CCL 4 lacked
specific information necessary in order to follow the decision-making
process for listing an individual contaminant on the Draft CCL 4.
Specific suggestions to improve transparency and clarity of the support
documents include:
    [cir] Develop a summary table that consolidates summary information
on all carried forward and nominated contaminants.
    [cir] Display results of the CCL 4 screening and classification
process in a manner that explicitly outlines the scoring schemes used
and the scientific rationale in applying the selection criteria.
    [cir] Provide examples for both microbial and chemical contaminants
that display the process of how contaminants were included on or
eliminated from the Draft CCL 4.
    [cir] Clearly describe and improve the process for removing
contaminants from prior CCLs, where appropriate, when such lists serve
as the basis for a new CCL.
    [cir] Explain the evaluation of CCL contaminants during the RD
process.
     The SAB recommended that EPA should utilize data from UCMR
3 monitoring as it becomes available.
     The SAB stated that the CCL 4 list includes a number of
contaminants carried forward from the CCL 3 without providing a sense
of the relative priority of the listed chemicals. The SAB recommended
EPA prioritize the list to inform future regulatory decision-making and
to help researchers focus their efforts.
    EPA Response: EPA has provided a more detailed response to the SAB
in the document, ``Response to SAB recommendations on the Draft CCL 4''
(USEPA, 2016h), which can be found in the docket for this action
available at www.regulations.gov by searching for docket EPA-HQ-OW-
2012-0217. This section summarizes EPA's response to some of the key
SAB recommendations.
    The agency has updated the technical support documents for the CCL
4 to increase the transparency of its decisions relative to the
contaminants included on the Final CCL 4. For instance, the CIS support
document provides examples showing the criteria and process for
including or excluding chemical and microbial contaminants from the CCL
4. Additionally, a summary table in the same support document presents
factors used to determine how the CCL 4 contaminants were selected. The
agency also summarizes the process used to evaluate contaminants under
RD 3 in section I.E.3 of this notice.
    While EPA agrees with the SAB about the importance of using UCMR
data to inform the CCL, the agency does not believe it is appropriate
to use preliminary UCMR 3 data to make final CCL 4 decisions. The UCMR
3 data set was not finalized within the timeframe for use and analysis
under CCL 4. The UCMR 3 monitoring period ended in December 2015 and
results are reported to EPA through 2016. After the monitoring period
is completed, the results undergo review for quality assurance and are
subject to change following further review by the analytical
laboratory, the PWS, the State and EPA. The agency will perform further
analysis of both the health effects and occurrence of contaminants
monitored under UCMR 3 during the RD 4 and CCL 5 development process.
    EPA identified the current occurrence, health effects and
analytical methods data needs of CCL 4 contaminants for RD 4
evaluations in section V of this notice. This data needs table is
presented to provide a sense of relative priority for listed
contaminants by identifying those contaminants likely to have
sufficient data for further evaluation under the next RD and those that
have research needs. As the agency continues to evaluate contaminants
on the CCL 4, EPA will work with agency and non-EPA scientists to
develop and collect the best available science to support decision-
making for future determinations.

B. Public Comments

1. General Comments on CCL 4
    EPA received comments, both in support of and against the carry
forward of contaminants from the CCL 3 to the Draft CCL 4. One
commenter asked for more information on the decision to carry forward
CCL 3 contaminants to the Draft CCL 4. Commenters not in support of the
carry forward of CCL 3 contaminants thought EPA should reassess the
science on all the CCL 3 contaminants. One commenter also thought EPA
should limit the number of contaminants on the CCL so that research for
the contaminants could be completed between one CCL and the next. One
commenter supported the carry forward approach because the CCL 3
contaminants already have data available that shows there may be a
potential public health impact. They also suggested that EPA should
continue to evaluate these contaminants until enough data are collected
to support a regulatory determination.
    EPA response: The reasons for carrying forward contaminants from
the CCL 3 to the CCL 4 are presented in section III.A of this notice.
EPA has continued to collect data and further evaluate the science for
many of the contaminants that were carried forward from the CCL 3 to
the CCL 4. For example, since the listing of contaminants on CCL 3, EPA
has monitored and collected occurrence data for several CCL
contaminants through the UCMR program. EPA has also further analyzed
and evaluated many of the CCL 3 contaminants that were carried forward
to CCL 4 under the RD 3 process. Exhibit 1 in section II.A of this
notice lists CCL 4 contaminants that were evaluated under these other
agency efforts. Although EPA carried forward contaminants from the CCL
3 to the CCL 4, EPA intends to collect new data and conduct further
evaluations of unregulated contaminants for CCL 5.
    EPA does not agree that the CCL should be limited to a certain
number of contaminants. The CCL identifies contaminants that are
``known, or anticipated to occur in PWSs,'' and is the first step in
identifying contaminants that may require regulation. Some of the
contaminants on the list may have sufficient information to make
regulatory determinations in the near term and some of the contaminants
on the list need additional data in order to determine the appropriate
agency action. While the SDWA does not limit the CCL to a particular
number of contaminants, the agency recognizes the need to communicate
data needs for contaminants included on the Final CCL 4. Therefore, EPA
has provided a summary of the current data needs for RD 4 evaluations
in section V of this notice. The agency will continue to evaluate data
needs through the RD 4 process and will continue to work with internal
and external researchers to discuss research needs and priorities.
2. Chemical Contaminants
a. Contaminants With Release Data
    EPA received comments that several contaminants listed based on

environmental release data for evaluating occurrence (e.g., ethylene
oxide, ethylene glycol, and toluene diisocyanate) should not be on the
CCL 4 because one or more of their intrinsic physical or chemical
properties would result in limited occurrence in water. Commenters
cited the hydrolysis and biodegradation rate, or quick volatilization
from water as reasons these chemicals should be removed from the Final
CCL 4. Additionally, commenters noted that some of these contaminants
have relatively short half-lives in water or may not be long-lived in
the environment and thus should not be listed on the Final CCL 4.
    EPA Response: EPA is including ethylene oxide, ethylene glycol, and
toluene diisocyanate on the Final CCL 4 because these contaminants may
be anticipated to occur in PWSs and may require regulation. Although no
occurrence information in finished or ambient water is available for
these contaminants, to be consistent with the CCL 4 protocol, EPA used
total environmental release data reported in the TRI to evaluate and
score the occurrence attributes. In response to comments citing that
EPA should consider physical and chemical properties, EPA conducted
additional analyses that considers physical and chemical properties and
environmental fate parameters to provide an alternate score for the
magnitude attribute. For this additional analysis on the specific
contaminants commented on (e.g., ethylene oxide, ethylene glycol, and
toluene diisocyanate), EPA used the persistence and mobility scoring
protocol (which is the protocol used for those chemicals with only
production data) as the basis for scoring the magnitude attribute as
described in the Final CCL 3: Classification of the PCCL to the CCL
(USEPA, 2009e), available in the docket for this action. The model
results for these contaminants using this alternate magnitude score
still indicated that the contaminants should be listed (for a summary
of how the classification model results were used to select
contaminants for CCL 4, please see USEPA, 2016e, available in the
docket for this action). These additional analyses are further
described in the ``Comment Response Document for the Fourth Drinking
Water Contaminant Candidate List (Categorized Public Comments)''
document, which is available in the docket for this action (USEPA,
2016f). Additionally, as the SAB (USEPA, 2016h) noted, ``contaminants
with a half-life in drinking water sources of days to weeks may still
pose a public health concern.''
    Considering the comments received on the Draft CCL 4, in future
CCLs, EPA may refine analyses to consider if physical and chemical
properties can be incorporated into the evaluations of contaminants
listed based on environmental release data for occurrence.
b. Cyanotoxins
    EPA received comments supporting the inclusion of cyanotoxins on
the CCL 4. Some comments requested that cyanotoxins be listed by
individual toxins rather than including cyanotoxins as a group on the
Final CCL 4 in order to prioritize research on health effects,
analytical methods, occurrence and treatment. Comments specifically
requested listing the key variants of microcystins, cylindrospermopsin,
anatoxin-a, saxitoxin and euglenophycin.
    EPA Response: EPA agrees that cyanotoxins should be included on the
CCL 4, and has included cyanotoxins as a group on the Final CCL 4. The
group of cyanotoxins includes all toxins produced by cyanobacteria
including but not limited to microcystins, cylindrospermopsin,
anatoxin-a and saxitoxin. EPA has provided CIS sheets for microcystin-
LR, cylindrospermopsin, anatoxin-a and saxitoxin. Under CCL 3,
cyanotoxins were listed as a group and EPA released CIS sheets for
microcystin-LR, cylindrospermopsin and anatoxin-a. Based on data
submitted in public comments, EPA updated previous CIS sheets and
developed a CIS sheet for saxitoxin. EPA was unable to develop a CIS
sheet for euglenophycin due to insufficient information on health and
occurrence. EPA acknowledges the comments to list specific cyanotoxin
compounds on the CCL instead of listing cyanotoxins as a group.
However, because of the similar sources of cyanotoxins (i.e.,
cyanobacteria) their management may be similar. Furthermore, due to
significant information gaps for some cyanotoxins (e.g., euglenophycin
and nodularin and many microcystin congeners), EPA has determined it
most appropriate to continue to list cyanotoxins as a group at this
time. EPA agrees that microcystins, cylindrospermopsin, anatoxin-a and
saxitoxin can be of concern for drinking water supplies. EPA
acknowledges associated data gaps for euglenophycin as well as those
for other cyanotoxins. EPA included total microcystins and six
microcystin congeners (-LA, -LF, -LR, -LY, -RR, and -YR),
cylindrospermopsin, anatoxin-a and nodularin on the proposed UCMR 4 for
monitoring by PWSs. The occurrence information collected under the UCMR
4 will be used to further evaluate the appropriate agency regulatory
determination and research actions.
c. Perfluorinated Compounds (PFOA and PFOS)
    EPA received a comment supporting the inclusion of
perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)
on the CCL 4. EPA also received comments that PFOS and/or PFOA should
not be listed on the Final CCL 4. The commenter supporting inclusion of
these chemicals on the CCL 4 cited their persistence in the environment
and toxicological effects as reasons to include them on the Final CCL
4, and encouraged EPA to consider these chemicals for drinking water
regulation. Commenters supporting removal of PFOA and/or PFOS from the
CCL 4 cited the low frequency of detections of PFOA and/or PFOS under
the UCMR 3 monitoring as of January 2015. Additional reasons cited by
commenters that these chemicals should not be listed on the Final CCL 4
are the voluntary efforts by manufacturers to reduce emissions and work
towards elimination of these chemicals from products.
    EPA Response: EPA is including PFOA and PFOS on the Final CCL 4
because these contaminants are known to occur in drinking water, are
persistent in the environment and in the human body, have shown to be
toxic in animal studies and may require regulation.
    As discussed in the summary of EPA responses to the SAB in this
section (IV.A) of the notice, EPA did not use preliminary UCMR 3
monitoring results for the CCL 4.
    EPA acknowledges the industry commitments to voluntarily reduce the
use and production of PFOA and PFOS; however, there are still a limited
number of ongoing uses of PFOA and PFOS. Additionally, these chemicals
are persistent in the environment and in the human body, which
indicates they may be present in water or migrate to drinking water
sources even after uses and production have been reduced or ceased, and
therefore potential exposure may still be of concern.
    In May 2016, EPA released lifetime health advisories for PFOA and
PFOS (USEPA, 2016i, available in the docket for today's action) and
Health Effects Support Documents based on the agency's assessment of
the latest peer reviewed science. The health advisories provide
federal, state, tribal and local officials with information on the
health risks of these chemicals, occurrence,

analytical methods and treatment technologies so that they can
determine what actions to take to protect consumers.
    In accordance with the SDWA, EPA will consider the occurrence data
from the final UCMR 3 data set, along with the peer reviewed health
effects assessments supporting the May 2016 PFOA and PFOS Health
Advisories, to make a regulatory determination whether or not PFOA and
PFOS require NPDWRs.
d. Pesticides
    Several public commenters requested that specific pesticides be
removed from the Final CCL 4. EPA agrees with commenters that three of
these pesticides (disulfoton, fenamiphos, and molinate) should not be
listed on the Final CCL 4; therefore, EPA is removing them from the
Final CCL 4. The evaluation of these three pesticides is summarized in
the following paragraphs.
(i) Disulfoton
    EPA received a comment from the public that disulfoton should not
be included on the Final CCL 4. The commenter noted that disulfoton had
zero or very few detections nationally on any previous round of UCMR
monitoring and therefore does not warrant national regulation.
    EPA Response: EPA agrees with the commenter that disulfoton should
not be included on the Final CCL 4. Disulfoton sales and distribution
were cancelled in the U.S., effective December 31, 2010, with remaining
product stocks to be used until depleted (74 FR 48551, September 23,
2009 (USEPA, 2009g)). The UCMR 1 finished water screening survey (SS)
found no detections of disulfoton in 2,300 samples from 295 PWSs. The
United States Geological Survey (USGS) has detected disulfoton
infrequently in ambient water. During the 1992-2001 USGS National
Water-Quality Assessment (NAWQA) Program monitoring, disulfoton was
detected in only 17 sites out of 7,118 ambient water sites sampled (see
the CIS for this contaminant (USEPA, 2016e)). Out of the 17 sites with
detections, only two sites had detects at levels greater than the
health reference level of potential concern for drinking water. Given
that disulfoton was detected in those two sites prior to its
cancellation, the agency expects that any potential disulfoton
occurrence in water will likely continue to decrease in the future.
Although persistent environmental contaminants may occur in a PWS after
its uses are cancelled, based on its physical and chemical properties,
disulfoton has low to moderate mobility in water and it is only
moderately persistent in the environment (see the CIS for this
contaminant (USEPA, 2016e), which can be found in the docket for this
action). Therefore its occurrence is expected to decrease over time.
    EPA is not including disulfoton on the Final CCL 4 because it is
not known or anticipated to occur in drinking water. Disulfoton likely
has low potential for public health concern based on its cancellation
status, zero detections in PWSs (from UCMR 1 data), and very few
detections in ambient water from a large number of sites sampled (by
the USGS NAWQA program).
(ii) Fenamiphos
    EPA received a comment from the public that fenamiphos should not
be included on the Final CCL 4. The commenter stated that the
registrant for fenamiphos agreed to cancel all uses, and all existing
stocks are to be used by October 6, 2017. The commenter stated that
very limited uses remain of products containing fenamiphos in the U.S.
and use will be discontinued after 2017.
    EPA Response: EPA agrees with the commenter that fenamiphos should
not be included on the Final CCL 4 because it is not anticipated to
occur in drinking water and is not likely to require regulation.
Fenamiphos product registrations were cancelled, and the sale and
distribution of fenamiphos by the registrant was prohibited on May 31,
2007. This cancellation followed a five- year phase-out period,
beginning in 2003, intended to limit and reduce production of
fenamiphos. The sale and distribution of any remaining stocks will be
prohibited after October 6, 2017 (79 FR 59262, October 1, 2014; USEPA,
2014c). Fenamiphos was not monitored under UCMR, thus no national scale
monitoring has been conducted in PWSs. While fenamiphos was not
included in the USGS NAWQA national-scale ambient water monitoring
(1992-2001), based on the USGS Pesticide National Synthesis Project
(USGS, 2012), fenamiphos use is estimated to have steadily declined.
The USGS estimated a usage level of approximately 1.0 million pounds/
year of widespread use in certain regions per year in 1992, which
declined to an estimated 0.2 million pounds/year in 2002 and further
declined to an estimated 0.03 million pounds/year of limited regional
uses in 2012. EPA expects fenamiphos occurrence in water will likely
continue to decrease due to the declining trend in usage for many years
and the prohibition on usage of existing stocks in the U.S. effective
after October 6, 2017.
    In summary, due to its registration cancellation status,
significant decline in usage (based on estimated data from 1992-2013),
moderate persistence in the environment, and the prohibition of
existing stocks (effective after October 6, 2017), EPA does not
anticipate fenamiphos to occur in PWSs or to require regulation,
therefore, it is not included on the Final CCL 4.
(iii) Molinate
    EPA received a comment from the public that molinate should not be
included on the Final CCL 4. The commenter noted that molinate had zero
or very few detections nationally on any previous round of UCMR
monitoring and therefore does not warrant national regulation.
    EPA Response: EPA agrees with the commenter that molinate should
not be included on the Final CCL 4. The UCMR 1 finished water
assessment monitoring found only one sample with a detection of
molinate out of 33,799 samples taken from 3,873 PWSs. The single sample
detection was below the health reference level of potential concern for
molinate in drinking water. Further, molinate sales and distribution
were cancelled in the U.S. effective July 1, 2009, with remaining
stocks required to be used by August 31, 2009, (73 FR 44261, July 30,
2008 (USEPA, 2008c)). This cancellation action concluded a six-year
scheduled phaseout of molinate. The agency is not including molinate on
the Final CCL 4 because it is not anticipated to occur in PWSs at
levels of public health concern. The agency expects the potential for
molinate to occur in water will likely continue to decrease due to the
prohibition on product use in the U.S. since 2009.
e. Manganese
    EPA received four comments that support the inclusion of manganese
and two comments that do not support the inclusion of manganese on CCL
4. Commenters supporting the inclusion of manganese on CCL 4 cited
recent studies that showed neurological effects in children and infants
exposed to excess manganese via drinking water. Commenters also noted
manganese frequently occurs in water and should be included on CCL 4 so
that national occurrence data can be obtained through UCMR monitoring.
Commenters who did not support the inclusion of manganese on the CCL 4
cited that the primary route of human exposure to manganese is through
food, not drinking

water. Also, commenters question the link between the consumption of
drinking water and developmental neurotoxicity from manganese exposure
to warrant inclusion on the CCL 4.
    EPA Response: EPA agrees with the commenters that support manganese
inclusion on the CCL 4, and is including manganese on the Final CCL 4
because it is known to occur in PWSs and may require regulation. The
evidence from the studies provided by commenters indicate that exposure
to excess manganese may present a substantial health threat to children
and infants. EPA is continuing to evaluate the potential risks to
children and infants based on over 30 recent studies cited by the
public during the nomination and comment period including those by
Bouchard et al. (2011), Oulhote et al. (2014) and Kern and colleagues
(2010, 2011), whom have indicated neurological effects stemming from
the exposure to excess manganese.
    EPA also agrees with the commenters assertion that manganese is
known to occur in PWSs. EPA has included the occurrence data used to
evaluate manganese in the CIS for this contaminant. This data includes
USGS monitoring of ambient water, as well as drinking water data from
several states. The data indicates that manganese is known to occur in
public drinking water supply wells and supports the previous
information from the National Inorganics and Radionuclides Survey
(NIRS). EPA has proposed to monitor manganese under UCMR 4.
    EPA has reviewed all of the current data submitted by commenters on
the manganese health effects and found that the existing 2004 Health
Advisory could warrant an update. Since manganese is not a regulated
contaminant in drinking water, the Secondary Maximum Contaminant Level
of 0.05 mg/L is not mandatory and does not require monitoring. The
current IRIS assessment for manganese dates to 1995 (USEPA, 1995b) and
the Health Advisory to 2004. The Agency for Toxic Substances and
Disease Registry 2012 Toxicological Profile did not establish
guidelines that applied to oral exposures and the Institute of Medicine
(2001) provides Tolerable Upper Intake Levels for developmental
lifestages and adults. The database of health effects studies for oral
manganese exposures has expanded considerably since the last EPA
assessment, therefore manganese is a good candidate for re-evaluation.
EPA intends to evaluate the new toxicological findings and UCMR 4
monitoring data and will use this information in future regulatory
decision-making, and to revise the current Health Advisory, if
appropriate. More detailed evaluations of the routes of exposure
usually occur in the regulatory determination and regulatory
development processes.
f. Nonylphenol
    EPA received two comments supporting the inclusion of nonylphenol
and three comments that nonylphenol should not be included on the Final
CCL 4. The commenters supporting inclusion of nonylphenol on the CCL 4
cited new health effects and occurrence data as reasons to include them
on the Final CCL 4 and stated that EPA has adequate justification to
include nonylphenol on the CCL based on this information. The
commenters requesting that nonylphenol not be included on the Final CCL
4 cited a surface water monitoring study from 2002 and industry efforts
to reduce surfactant usage as reasons nonylphenol should not be listed
on the Final CCL 4. The main use of nonylphenol is in the manufacture
of nonylphenol ethoxylates, which have been used in a wide range of
industrial applications and consumer products including laundry
detergents, cleaners, degreasers, paints and coatings and other uses
(79 FR 59186, October 1, 2014 (USEPA, 2014d)).
    EPA Response: EPA is including nonylphenol on the Final CCL 4 as
proposed because it is anticipated to occur in drinking water, has
potential adverse health effects (Bontje et al., 2005), and may require
regulation. EPA evaluated the 2002 USGS reconnaissance study (Kolpin et
al., 2002) identified by the commenter and used it to evaluate the
occurrence of nonylphenol. While there were more recent finished water
studies available, EPA considers the 2002 USGS study as the most
appropriate study to evaluate the occurrence of nonylphenol for CCL 4
given the greater number of samples and larger geographic scale.
Additionally, more recent studies indicate that nonylphenol has been
detected in drinking water. While EPA appreciates the information from
commenters on reduced usage of nonylphenol, we believe measured
occurrence data from water sources are preferred over production or
usage information when evaluating the likelihood of occurrence in
drinking water.
3. Microbial Contaminants
a. Overall Process Comments
    EPA received comments arguing that the follow-through on the
microbes listed in previous CCLs has been inadequate, that EPA should
identify high priority pathogens on the CCL 4 and identify information
gaps and barriers to obtaining information associated with each
pathogen. EPA received comments requesting an open process for
prioritizing and collecting information, to adopt a collaborative
method development process and to rank microbes by treatability. EPA
also received comments to focus priorities on distribution and plumbing
system biofilm concerns and to evaluate microbial contaminants in the
context of diverse water supplies such as drinking water sources from
water reuse treatment facilities.
    EPA Response: EPA's criteria for evaluating and prioritizing
pathogens for inclusion in the CCL 3 included health effects,
waterborne disease outbreaks (WBDO) and occurrence information (73 FR
9628 (USEPA, 2008a)). EPA developed and implemented a systematic
strategy and set of criteria for selecting the pathogens for CCL 3.
This is the screening and scoring process described in detail in the
support documents in the docket of the Final CCL 3 (e.g., see the Final
Contaminant Candidate List 3 Microbes: PCCL to CCL Process for more
information on all of the scores). The CCL 3 and CCL 4 processes
provided multiple opportunities for public input (e.g., nominations,
public comment) to allow for an open process. In order to provide
additional clarity to the scoring process, EPA is including an example
schematic describing the process of evaluating a pathogen for inclusion
on the list and a pathogen for exclusion from the list. This schematic
can be found in the CIS's for the Final Fourth Contaminant Candidate
List (USEPA, 2016e). EPA acknowledges the request to identify
information gaps; therefore, data needs are described in section V of
this Federal Register notice.
    The EPA's Office of Water coordinates with EPA's Office of Research
and Development to discuss research needs and priorities. Research on
distribution system and premise plumbing biofilm concerns has been
incorporated into EPA's strategic research plan. EPA acknowledges the
comments on diverse water supplies and method development and will
consider these comments as it develops future research priorities.
b. Pathogens for Inclusion
    EPA received comments supporting the proposed inclusion of
Mycobacterium avium, Legionella pneumophila, Naegleria fowleri,
enteroviruses and Heterotrophic Plate Count (HPC). EPA also received

comments requesting recommendations for Legionella pneumophila
management.
    EPA Response: EPA included Mycobacterium avium, Legionella
pneumophila, Naegleria fowleri, and enteroviruses on the Final CCL 3
and were therefore carried forward to the draft and Final CCL 4. While
the broader issue of the management of Legionella pneumophila is
outside the scope of today's action, the agency agrees it is of great
importance and Legionella remains a risk to building water systems. In
September 2016, EPA released a document reviewing the available
technology to treat Legionella titled Technologies for Legionella
Control in Premise Plumbing Systems: Scientific Literature Review
(USEPA, 2016j). This document provides information to state and local
decision-makers about how they might utilize treatment as part of their
efforts to manage Legionella risks in building water systems.
    EPA disagrees that HPC should be included on CCL 4. The group of
HPC usually includes a diverse group of microorganisms that are part of
the natural environment in water. Available epidemiological evidence
shows no relationship between gastrointestinal illness and HPC bacteria
in drinking water (Calderon, 1988; Calderon and Mood, 1991; Payment et
al., 1997; Bartram J et al., 2003). Thus, EPA considers the potential
health risk of HPC bacteria in drinking water as likely negligible and
is not including HPC on the Final CCL 4. In addition, HPC bacteria are
addressed under the Surface Water Treatment Rule as a treatment
technique where they can be monitored in lieu of a disinfectant
residual because HPC is an alternative method of determining
disinfectant residual levels.
c. Pathogens for Exclusion
    EPA received comments not supporting the proposed inclusion of
Escherichia coli O157 and Helicobacter pylori, noting these pathogens
were unlikely to occur in treated drinking water.
    EPA Response: EPA's criteria for evaluating and prioritizing
pathogens for inclusion in the Draft CCL 3 Federal Register notice,
included health effects, WBDO and occurrence information (73 FR 9628
(USEPA, 2008a)). Treatability was not part of the scoring criteria
considered for CCL 3 inclusion. Although some of the microbes listed in
the Draft CCL 4 may be well controlled by drinking water treatment
(i.e., disinfection), not all PWSs in the U.S. are required to treat.
For example, approximately thirty percent of the 40,000 community
ground water systems do not have disinfection treatment (USEPA, 2013).
For the reasons discussed in detail in the Draft CCL 3 Federal Register
notice (73 FR 9628 ((USEPA, 2008a)), EPA did not preclude pathogens
from CCL 3 and CCL 4 based on their potential to be controlled by
existing treatment technique regulations.

V. Data Needs for CCL 4 Contaminants

    After the listing process, the CCL 4 contaminants will be further
evaluated in a separate action called Regulatory Determination 4 (RD
4). The process used to previously evaluate CCL 3 contaminants under RD
3 is described in section I.E.3 of this notice. EPA anticipates using a
similar process to evaluate CCL 4 contaminants under RD 4, although it
is possible that some modifications may be made to this process. In the
initial phases of this process, EPA determines if sufficient data are
available to meet the three RD criteria set forth in SDWA section
1412(b)(1) and previously outlined in section I.D.4 of this notice. If
sufficient data are available to meet all three statutory criteria, a
regulatory determination may be made. As discussed in section I.D.4,
SDWA requires EPA to make regulatory determinations every five years on
at least five CCL contaminants.
    The SAB and other commenters have recommended additional
prioritization of the CCL 4 contaminants to communicate research needs,
help focus efforts for researchers, and inform future regulatory
decision-making. EPA acknowledges that many contaminants on the CCL 4
have substantial data and information needs to fulfill in order for the
agency to make a regulatory determination in accordance with SDWA 1412
(b)(1)(A). These current data needs are described in the following
section, and are presented in Exhibit 2. By identifying those
contaminants that need additional research and information, EPA is
communicating to stakeholders both research priorities and gaps for
these contaminants.
Categorization of Contaminants
    EPA assessed the data and information gathered on the CCL 4
contaminants and generated a table (Exhibit 2) to help identify data/
information needs for further evaluation under RD 4. To develop this
table, EPA began with the information contained in the data
availability/Phase 1 table included in Appendix D of the Protocol for
the RD 3 (USEPA, 2014b), which describes the status of the best
available occurrence data and health effects assessments for CCL 3
contaminants. EPA updated the occurrence data needs for CCL 4
contaminants by including which contaminants were monitored on the UCMR
3, and updated the health effects data needs based on available EPA or
other non-EPA peer reviewed assessments as of May 2016. Since manganese
and nonylphenol were nominated and added to the CCL 4 (not carried
forward from CCL 3), data collected under CCL 4 was included in the
Contaminant Information Sheets (USEPA, 2016e) for these contaminants
and was used to assess the data needs. EPA characterized each chemical
contaminant included on the Final CCL 4 based on their health effects,
occurrence and analytical methods data needs.
    EPA then categorized contaminants into six categories depending
upon the availability of their occurrence data and health assessment.
Contaminants in Group A have nationally representative finished
drinking water data and a peer reviewed health assessment and are
likely to have sufficient data available to be placed on a short list
for further assessment under RD 4. Contaminants in Group B have
finished drinking water data that is not nationally representative and
peer reviewed health assessments. These contaminants may have
sufficient data to be placed on a short list for further assessment
under RD 4, particularly if the non-nationally representative
occurrence data shows detections at levels of public health concern.
Contaminants in groups C, D, E, and F of Exhibit 2 that lack either a
peer reviewed health assessment or finished water data have more
substantial data needs and are unlikely to have sufficient information
to allow further assessment under the RD 4. For these contaminants, EPA
plans to identify them as research priorities and work to fill their
research needs such as evaluating the potential for monitoring under
the UCMR or identifying those contaminants as priorities for health
effects research. The health effects and occurrence data sources used
to classify data needs are featured in Appendix 6 of the CISs for the
Final Fourth CCL in the docket (USEPA, 2016e). The following sections
describe the types of data or information gaps outlined in Exhibit 2
and provide examples.

A. Health Effects

    Under the RD process, EPA relies on external peer-reviewed health
assessments to determine if and at what level a contaminant ``may have
an adverse effect on the health of persons.'' Health effects data
sources evaluated for

RD 3 included EPA health assessments, or peer reviewed health
assessments developed by other organizations such as the National
Academy of Sciences, the Agency for Toxic Substances and Disease
Registry, World Health Organization, the California EPA's Office of
Environmental Health Hazard Assessment, Registry of Toxic Effects of
Chemical Substances, and/or supplemental data from a single study, if
the health assessment is peer reviewed and uses comparable methods,
standards and guidelines to an EPA health assessment.
    As shown in Exhibit 2, EPA categorized the health effects data
needs in the following way:
    1. If a peer reviewed health assessment is available or is in the
process of being revised, the contaminant is considered to have health
effects data available.
    2. If a peer reviewed health assessment is not available, then the
contaminant is considered to not have health effects data currently
available.

B. Occurrence

    For RD evaluations, the occurrence data availability assessment is
used to identify contaminants that may have sufficient data and
information to characterize their status as known or likely to occur in
PWSs. EPA uses data from many sources to evaluate occurrence for
contaminants considered for RD (see Appendix C of USEPA, 2014b for
occurrence data sources evaluated under RD 3). For this evaluation, EPA
prefers to have nationally representative finished drinking water
occurrence data, but finished drinking water data that are not
nationally representative may also be used to determine if the
contaminant occurs frequently at levels of public health concern. In
addition, the agency evaluates supplemental sources of information
(e.g., ambient/source water occurrence, production/use and
environmental release data). For the purposes of identifying current
data needs for RD 4, as shown in Exhibit 2, EPA categorized the
occurrence data needs in the following way:
     Finished drinking water occurrence data that are
nationally representative are available.
    [cir] Data sources may include UCMRs (i.e., UCMR 1, UCMR 2 and UCMR
3), the Unregulated Contaminant Monitoring Program (Round 1 and Round
2) and NIRS.
     Finished drinking water occurrence data that are not
nationally representative are available. These data may include:
    [cir] Finished water assessments by federal agencies (e.g., EPA,
the U.S. Department of Agriculture and USGS). These may include
assessments that are geographically distributed across the nation but
are not intended to be statistically representative of the nation
(e.g., the Disinfection By-Product Rule Information Collection
Request).
    [cir] State-level finished water monitoring data.
    [cir] Research performed by institutions and universities (e.g.,
scientific literature), including targeted or local monitoring studies.
    [cir] Various reports from the Centers for Disease Control and the
scientific literature for microbes.
     Finished drinking water occurrence data are not available.
    [cir] The best available data sources may include environmental
release data (such as TRI data or pesticide application data) or
ambient water data.
    EPA has also indicated with a footnote in the occurrence data
column, highlighting which contaminants are proposed for monitoring
under the UCMR 4 from 2018-2020. Therefore, although some of the
contaminants that may be monitored under UCMR 4 are shown in this table
as currently having data gaps for occurrence (e.g., they only have
drinking water data that is not nationally representative or release
data), EPA has proposed to fill those occurrence data needs for future
RD evaluations.

C. Analytical Methods

    To conduct nationally representative drinking water occurrence
studies that could support a regulatory determination, EPA needs to
have an analytical method that is suitable for the drinking water
matrix and is robust enough to be used by many laboratories to conduct
national studies and/or compliance monitoring. For the purpose of CCL
4, EPA assessed the status of the development of analytical methods for
drinking water and determined estimated reporting levels for each
contaminant. EPA also assessed method sensitivity with respect to the
HRL for the chemical contaminants. Method sensitivity is measured by
using method specific reporting levels, lowest concentration minimum
reporting levels, and promulgated minimum reporting level. While there
are many methods for monitoring the CCL 4 pathogens available from
scientific papers and consensus organizations, not all of them may be
appropriate for use in drinking water or for a national monitoring
effort. Of the CCL 4 pathogens, only enterovirus and caliciviruses have
an EPA-approved method for drinking water. The status of drinking water
analytical methods for the CCL chemical contaminants, as of May 2016,
is presented in Exhibit 2. EPA categorized the analytical method needs
in the following way:
     An EPA drinking water method, with estimated reporting
levels that are adequate for analysis relative to the current HRL or
health assessment is available.
     An EPA drinking water method is available but the minimum
reporting level (MRL) does not allow for quantitation of the
contaminant at a concentration below the current HRL. These methods are
denoted in Exhibit 2 by ``(MRL>HRL)''.
     An EPA drinking water method is currently being developed.
     An EPA drinking water method is not available.
    Although not shown in Exhibit 2, EPA also considers other
government and consensus methods (e.g., Standard Methods and ASTM,
International) when considering analytical methods that may be used or
modified for UCMR monitoring.

                Exhibit 2--Regulatory Determination Data/Information Needs for CCL 4 Contaminants
----------------------------------------------------------------------------------------------------------------
                                                 What is the best     Is a health
            CASRN                Common name         available        assessment     Is an EPA analytical method
                                                 occurrence data?     available?              available?
----------------------------------------------------------------------------------------------------------------
     (A) Contaminants with Nationally Representative Finished Water Occurrence Data and Peer Reviewed Health
                                                   Assessments
----------------------------------------------------------------------------------------------------------------
630-20-6....................  1,1,1,2-           National........  Yes \a\.........  Yes.
                               Tetrachloroethan
                               e.
96-18-4.....................  1,2,3-             National........  Yes.............  Yes (MRL > HRL).
                               Trichloropropane.
123-91-1....................  1,4-Dioxane......  National........  Yes.............  Yes.
16655-82-6..................  3-                 National........  Yes \b\.........  Yes.
                               Hydroxycarbofura
                               n.
34256-82-1..................  Acetochlor.......  National........  Yes.............  Yes.
187022-11-3.................  Acetochlor         National........  Yes \b\.........  Yes.
                               ethanesulfonic
                               acid (ESA).

194992-44-4.................  Acetochlor         National........  Yes \b\.........  Yes.
                               oxanilic acid
                               (OA).
142363-53-9.................  Alachlor           National........  Yes.............  Yes.
                               ethanesulfonic
                               acid (ESA).
171262-17-2.................  Alachlor oxanilic  National........  Yes \b\.........  Yes (MRL > HRL).
                               acid (OA).
14866-68-3..................  Chlorate.........  National........  Yes.............  Yes.
7440-48-4...................  Cobalt...........  National........  Yes \a\.........  Yes.
NA..........................  Enterovirus......  National........  Yes.............  Yes.
7439-96-5...................  Manganese........  National \ c\...  In Development..  Yes.
74-83-9.....................  Methyl bromide     National........  Yes \a\.........  Yes.
                               (Bromomethane).
51218-45-2..................  Metolachlor......  National........  Yes.............  Yes.
171118-09-5.................  Metolachlor        National........  Yes.............  Yes.
                               ethanesulfonic
                               acid (ESA).
152019-73-3.................  Metolachlor        National........  Yes.............  Yes.
                               oxanilic acid
                               (OA).
7439-98-7...................  Molybdenum.......  National........  In Development..  Yes.
98-95-3.....................  Nitrobenzene.....  National........  Yes.............  Yes.
55-18-5.....................  N-                 National........  Yes.............  Yes (MRL > HRL).
                               Nitrosodiethylam
                               ine (NDEA).
62-75-9.....................  N-                 National........  Yes \a\.........  Yes (MRL > HRL).
                               nitrosodimethyla
                               mine (NDMA).
621-64-7....................  N-Nitroso-di-n-    National........  Yes.............  Yes (MRL > HRL).
                               propylamine
                               (NDPA).
930-55-2....................  N-                 National........  Yes \a\.........  Yes.
                               nitrosopyrrolidi
                               ne (NPYR).
1763-23-1...................  Perfluorooctane    National........  Yes.............  Yes.
                               sulfonic acid
                               (PFOS).
335-67-1....................  Perfluorooctanoic  National........  Yes.............  Yes.
                               acid (PFOA).
121-82-4....................  RDX..............  National........  In Development..  Yes.
7440-62-2...................  Vanadium.........  National........  Yes \a\.........  Yes.
----------------------------------------------------------------------------------------------------------------
   (B) Contaminants With Non-Nationally Representative Finished Water Occurrence Data and Peer Reviewed Health
                                                   Assessments
----------------------------------------------------------------------------------------------------------------
71-36-3.....................  1-Butanol........  Non-National \c\  In Development..  Yes.
30560-19-1..................  Acephate.........  Non-National....  Yes.............  Yes.
107-02-8....................  Acrolein.........  Non-National....  Yes \a\.........  No.
NA..........................  Adenovirus.......  Non-National....  Yes.............  No.
319-84-6....................  alpha-             Non-National \c\  Yes.............  Yes (MRL > HRL).
                               Hexachlorocycloh
                               exane.
741-58-2....................  Bensulide........  Non-National....  Yes.............  Yes.
100-44-7....................  Benzyl chloride..  Non-National....  Yes \a\.........  No.
NA..........................  Caliciviruses....  Non-National....  Yes.............  Yes.
133-06-2....................  Captan...........  Non-National....  Yes.............  No.
NA..........................  Cyanotoxins......  Non-National \d\  Yes for           Yes.
                                                                    microcystins
                                                                    and
                                                                    cylindrospermop
                                                                    sin, no for
                                                                    other
                                                                    cyanotoxins.
141-66-2....................  Dicrotophos......  Non-National....  Yes.............  Yes.
330-54-1....................  Diuron...........  Non-National....  Yes.............  Yes.
13194-48-4..................  Ethoprop.........  Non-National \c\  Yes.............  Yes.
107-21-1....................  Ethylene glycol..  Non-National....  Yes.............  No.
96-45-7.....................  Ethylene thiourea  Non-National....  Yes.............  No.
50-00-0.....................  Formaldehyde.....  Non-National....  Yes.............  Yes.
NA..........................  Legionella         Non-National....  Yes.............  In Development.
                               pneumophila.
10265-92-6..................  Methamidophos....  Non-National....  Yes.............  Yes.
NA..........................  Mycobacterium      Non-National....  Yes.............  In Development.
                               avium.
86-30-6.....................  N-                 Non-National....  Yes \a\.........  No.
                               Nitrosodiphenyla
                               mine (NDPhA).
301-12-2....................  Oxydemeton-methyl  Non-National....  Yes.............  Yes.
42874-03-3..................  Oxyfluorfen......  Non-National \c\  Yes.............  Yes.
52645-53-1..................  Permethrin.......  Non-National \c\  Yes.............  Yes.
41198-08-7..................  Profenofos.......  Non-National \c\  Yes.............  Yes.
107534-96-3.................  Tebuconazole.....  Non-National \c\  Yes.............  Yes.
78-48-8.....................  Tribufos.........  Non-National \c\  Yes.............  Yes.
50471-44-8..................  Vinclozolin......  Non-National....  Yes.............  Yes.
137-30-4....................  Ziram............  Non-National....  Yes.............  No.
----------------------------------------------------------------------------------------------------------------
   (C) Contaminants With Nationally Representative Finished Water Occurrence Data Lacking Peer Reviewed Health
                                                   Assessments
----------------------------------------------------------------------------------------------------------------
75-34-3.....................  1,1-               National........  No \a\..........  Yes.
                               Dichloroethane.
106-99-0....................  1,3-Butadiene....  National........  No..............  Yes (MRL > HRL).
74-87-3.....................  Chloromethane      National........  No..............  Yes.
                               (Methyl
                               chloride).
474-86-2....................  Equilin..........  National........  No..............  Yes.
50-28-2.....................  Estradiol (17-     National........  No..............  Yes.
                               beta estradiol).
50-27-1.....................  Estriol..........  National........  No..............  Yes.
53-16-7.....................  Estrone..........  National........  No..............  Yes.
57-63-6.....................  Ethinyl Estradiol  National........  No..............  Yes.
                               (17-alpha
                               ethynyl
                               estradiol).
7440-56-4...................  Germanium........  National \c\....  No..............  Yes.
74-97-5.....................  Halon 1011         National........  No..............  Yes.
                               (bromochlorometh
                               ane).
75-45-6.....................  HCFC-22..........  National........  No..............  Yes.
1634-04-4...................  Methyl tert-butyl  National........  No..............  Yes.
                               ether (MTBE).
103-65-1....................  n-Propylbenzene..  National........  No \a\..........  Yes.

135-98-8....................  sec-Butylbenzene.  National........  No \a\..........  Yes.
13494-80-9..................  Tellurium........  National........  No..............  No.
----------------------------------------------------------------------------------------------------------------
 (D) Contaminants With Non-Nationally Representative Finished Water Occurrence Data Lacking Peer Reviewed Health
                                                   Assessments
----------------------------------------------------------------------------------------------------------------
57-91-0.....................  17alpha-estradiol  Non-National....  No..............  In Development.
75-07-0.....................  Acetaldehyde.....  Non-National....  No..............  Yes.
62-53-3.....................  Aniline..........  Non-National....  No \a\..........  No.
25013-16-5..................  Butylated          Non-National \c\  No..............  Yes.
                               hydroxyanisole.
517-09-9....................  Equilenin........  Non-National....  No..............  In Development.
114-07-8....................  Erythromycin.....  Non-National....  No..............  In Development.
110-54-3....................  Hexane...........  Non-National....  No \a\..........  No.
72-33-3.....................  Mestranol........  Non-National....  No..............  No.
NA..........................  Naegleria fowleri  Non-National....  No..............  No.
25154-52-3..................  Nonylphenol......  Non-National....  No..............  No.
68-22-4.....................  Norethindrone (19- Non-National....  No..............  In Development.
                               Norethisterone).
----------------------------------------------------------------------------------------------------------------
          (E) Contaminants With Peer Reviewed Health Assessments Lacking Finished Water Occurrence Data
----------------------------------------------------------------------------------------------------------------
107-18-6....................  2-Propen-1-ol....  Release \c\.....  Yes \a\.........  Yes.
110429-62-4.................  Clethodim........  Release.........  Yes.............  No.
55290-64-7..................  Dimethipin.......  Release \c\.....  Yes.............  Yes.
NA..........................  Escherichia coli   No Data.........  Yes.............  No.
                               (O157).
NA..........................  Helicobacter       No Data.........  Yes.............  No.
                               pylori \e\.
NA..........................  Hepatitis A virus  No Data.........  Yes.............  No.
302-01-2....................  Hydrazine........  Release.........  Yes \a\.........  No.
67-56-1.....................  Methanol.........  Release.........  Yes.............  No.
55-63-0.....................  Nitroglycerin....  Release.........  Yes \a\.........  No.
872-50-4....................  N-Methyl-2-        Release.........  Yes.............  No.
                               pyrrolidone.
75-56-9.....................  Oxirane, methyl-.  Release.........  Yes.............  No.
91-22-5.....................  Quinoline........  Release \c\.....  Yes.............  Yes (MRL > HRL).
112410-23-8.................  Tebufenozide.....  Release.........  Yes.............  Yes.
59669-26-0..................  Thiodicarb.......  Release.........  Yes.............  No.
23564-05-8..................  Thiophanate-       Release.........  Yes.............  No.
                               methyl.
76-87-9.....................  Triphenyltin       Release.........  Yes.............  No.
                               hydroxide (TPTH).
----------------------------------------------------------------------------------------------------------------
      (F) Contaminants Lacking Finished Water Occurrence Data and Current, Peer Reviewed Health Assessments
----------------------------------------------------------------------------------------------------------------
109-86-4....................  2-Methoxyethanol.  Release \c\.....  No \a\..........  Yes.
101-77-9....................  4,4'-              Release.........  No..............  No.
                               Methylenedianili
                               ne.
60-35-5.....................  Acetamide........  Release.........  No..............  No.
NA..........................  Campylobacter      No Data.........  No..............  No.
                               jejuni.
80-15-9.....................  Cumene             Release.........  No..............  No.
                               hydroperoxide.
75-21-8.....................  Ethylene oxide...  Release.........  No..............  No.
95-53-4.....................  o-Toluidine......  Release \c\.....  No \a\..........  Yes.
NA..........................  Salmonella         No Data.........  No..............  No.
                               enteric.
NA..........................  Shigella sonnei..  No Data.........  No..............  No.
26471-62-5..................  Toluene            Release.........  No..............  No.
                               diisocyanate.
121-44-8....................  Triethylamine....  Release.........  No..............  No.
51-79-6.....................  Urethane.........  Release.........  No..............  No.
----------------------------------------------------------------------------------------------------------------
Key to Exhibit:
National = Finished drinking water occurrence data that are nationally representative are available.
Non-National = Finished drinking water occurrence data that are not nationally representative are available.
In Development = Revised health assessment or analytical method is currently being developed.
\a\ Provisional Peer Reviewed Toxicity Value (PPRTV) in the form of chronic, oral RfD subchronic, oral RfD,
  cancer weight evidence, or cancer slope factor available.
\b\ The parent health assessment was used for the metabolite. There is no independent health assessment
  available for the metabolite.
\c\ Proposed for UCMR 4.
\d\ Evaluations of occurrence data availability for cyanotoxins in this table are based on anatoxin-a,
  cylindrospermopsin, and microcystin-LR. Cyanotoxins proposed for UCMR 4 monitoring include total microcystins
  (MC), MC-LA, MC-LF, MC-LR, MC-LY, MC-RR, MC-YR, nodularin, anatoxin-a and cylindrospermopsin.

VI. Next Steps and Future Contaminant Candidate Lists

    The CCL process is critical to shaping the future direction of the
drinking water program. The agency will continue to gather information
and evaluate contaminants on the CCL 4 to make regulatory
determinations for at least five contaminants. The agency will also
continue to refine the CCL process and gather more data to identify
contaminants for CCL 5. EPA will continue to work to prioritize
contaminants on the CCL 4, both for RD and for additional research and
data collection.

References

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    Dated: November 9, 2016.
Joel Beauvais,
Deputy Assistant Administrator, Office of Water.
[FR Doc. 2016-27667 Filed 11-16-16; 8:45 am]
 BILLING CODE 6560-50-P