`[Federal Register Volume 89, Number 242 (Tuesday, December 17, 2024)]
[Rules and Regulations]
[Pages 101914-101938]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-29483]



[[Page 101914]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

[EPA-HQ-OW-2018-0056; FRL 6322-03-OW]
RIN 2040-AF79


Water Quality Standards; Establishment of a Numeric Criterion for 
Selenium for the State of California

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (the EPA or the Agency) is 
amending a Federal Clean Water Act (CWA) rule, the California Toxics 
Rule, to promulgate a final, revised statewide chronic freshwater 
selenium water quality criterion applicable to certain California 
waters to protect aquatic life and aquatic-dependent wildlife from 
exposure to toxic levels of selenium. This revised criterion builds 
upon the science underlying the EPA's current national CWA section 
304(a) recommended aquatic life freshwater criterion for selenium.

DATES: This rule is effective on January 16, 2025. The incorporation by 
reference of certain publications listed in the rule is approved by the 
Director of the Federal Register as of January 16, 2025.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OW-2018-0056. All documents in the docket are 
listed on the https://www.regulations.gov website. Although listed in 
the index, some information is not publicly available, e.g., 
confidential business information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available electronically 
through www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Maria Letourneau, Office of Water, 
Standards and Health Protection Division (4305T), Environmental 
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460; 
telephone number: (202) 566-2700; email address: 
[email protected]; or Diane Fleck, Water Division (WTR-2-1), 
Environmental Protection Agency Region 9, 75 Hawthorne Street, San 
Francisco, CA 94105; telephone number: (213) 244-1836; email address: 
[email protected].

SUPPLEMENTARY INFORMATION: This final rule is organized as follows:

I. General Information
    A. Applicability
    B. The EPA's Development of the Final Rule
II. Background
    A. Statutory and Regulatory Authority
    B. Applicable Selenium Criteria in California
    C. California Toxics Rule and Endangered Species Act 
Consultation
    D. Litigation
    E. Selenium and Sources of Selenium
III. Final Freshwater Chronic Selenium Criterion
    A. The EPA's Approach
    B. Administrator's Determination of Necessity
    C. Final Chronic Selenium Criterion for California's Fresh 
Waters
    D. Implementation of the Final Chronic Selenium Criterion in 
California
    E. Incorporation by Reference
IV. Endangered Species Act
V. Applicability of the EPA-Promulgated Water Quality Standards
VI. Conditions When Federal Standards Would Be Withdrawn
VII. Alternative Regulatory Approaches
VIII. Economic Analysis
IX. Statutory and Executive Orders
    A. Executive Order 12866 (Regulatory Planning and Review) and 
Executive Order 14094 (Modernizing Regulatory Review)
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132 (Federalism)
    F. Executive Order 13175 (Consultation and Coordination With 
Indian Tribal Governments)
    G. Executive Order 13045 (Protection of Children From 
Environmental Health and Safety Risks)
    H. Executive Order 13211 (Actions That Significantly Affect 
Energy Supply, Distribution, or Use)
    I. National Technology Transfer and Advancement Act of 1995
    J. Executive Order 12898 (Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations) and Executive Order 14096 (Revitalizing Our Nation's 
Commitment to Environmental Justice for All)
    K. Congressional Review Act (CRA)

I. General Information

A. Applicability

    Federal water quality standards (WQS) promulgated by the EPA in 
this rule will be the applicable WQS for certain waters in California 
for Clean Water Act (CWA) purposes after the effective date of this 
rule. Specifically, the chronic freshwater selenium criterion in the 
final rule will apply to California waters in a manner consistent with 
the California Toxics Rule (CTR) and the EPA's proposed rulemaking for 
this action (83 FR 64059, December 13, 2018). The freshwater and 
saltwater aquatic life criteria listed in the CTR apply as follows: (1) 
the freshwater criteria apply at salinities of 1 part per thousand and 
below at locations where this occurs 95% or more of the time; (2) 
saltwater criteria apply at salinities of 10 parts per thousand and 
above at locations where this occurs 95% or more of the time; and (3) 
the more stringent of the two apply at salinities between 1 and 10 
parts per thousand. As a result, many estuarine waters will be covered 
by this rule.
    WQS serve as the basis for CWA programs, such as National Pollutant 
Discharge Elimination System (NPDES) permitting and identifying 
impaired waters under CWA section 303(d). Categories and entities that 
could potentially be affected by this rule include the following:

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                                      Examples of potentially affected
             Category                             entities
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Industry..........................  Industries discharging pollutants to
                                     certain waters of California.
Municipalities....................  Publicly owned treatment works or
                                     other facilities discharging
                                     pollutants to certain waters of
                                     California.
Stormwater Management Districts...  Entities responsible for managing
                                     stormwater discharges to certain
                                     waters of California.
Agriculture.......................  Agricultural entities discharging to
                                     certain waters of California.
------------------------------------------------------------------------

    This table is not exhaustive but, rather, it provides a guide that 
identifies entities that could be affected by this action. If you have 
questions regarding the effect of this action on a particular entity, 
please consult the person listed in the FOR FURTHER INFORMATION CONTACT 
section.

B. The EPA's Development of the Final Rule

    On November 29, 2018, the Administrator of the EPA signed a 
proposed rulemaking to establish a

[[Page 101915]]

selenium water quality criterion applicable to California that protects 
aquatic life and aquatic-dependent wildlife in certain waters of 
California. The proposal was published in the Federal Register at 83 FR 
64059 on December 13, 2018. For the proposed rulemaking, the EPA 
provided a 60-day public comment period with a 45-day extension and 
held two public hearings on March 19 and March 20, 2019, to accept 
verbal public comments. By the end of the public comment period on 
March 28, 2019, the EPA received a total of 32 comments on a range of 
issues submitted by organizations and individuals to the docket for the 
rule and during the two public hearings.
    For the final rule, the EPA carefully considered the public 
comments and feedback the Agency received on the proposed rulemaking. 
In relevant sections of the preamble below, the EPA provides brief 
summaries of certain comments. Some comments addressed issues beyond 
the scope of this rule. For all the comments the EPA received and the 
EPA's responses, see the EPA's Response to Comments document in the 
public docket for this rule: Docket ID No. EPA-HQ-OW-2018-0056.

II. Background

A. Statutory and Regulatory Authority

    The CWA establishes the basic structure for regulating pollutant 
discharges from point sources into the waters of the United States. In 
the CWA, Congress established the national objective to restore and 
maintain the chemical, physical, and biological integrity of the 
Nation's waters. The CWA also sets forth the interim goal of achieving 
water quality, wherever attainable, that provides for both: (1) the 
protection and propagation of fish, shellfish, and wildlife; and (2) 
recreation in and on the water (sections 101(a) and 101(a)(2)). 33 
U.S.C. 1251(a), (a)(2). To help achieve these goals, the CWA created 
two complementary structures for regulating discharges in CWA section 
402 NPDES permits: first, technology-based effluent limitations (TBELs) 
that set a floor for the performance for categories of regulated 
dischargers; and second, water quality-based effluent limitations 
(WQBELs) that are established where TBELs are insufficient to meet 
applicable WQS or site-specific water quality goals. See 33 U.S.C. 
1342(a). TBELs in NPDES permits are derived from secondary treatment 
standards (for publicly owned treatment works), effluent limitations 
guidelines (CWA sections 301 and 304, 33 U.S.C. 1311 and 1314), new 
source performance standards (CWA section 306, 33 U.S.C. 1316) 
promulgated by the EPA, and/or established on a case-by-case basis 
under section 402(a)(1) of the Act (to the extent that EPA-promulgated 
effluent limitations are inapplicable). If TBELs are not sufficient to 
achieve the WQS in the receiving water, the CWA (section 301(b)(1)(c), 
33 U.S.C. 1311(b)(1)(c)) and the EPA's NPDES regulation, 40 CFR 
122.44(d), require that the permit writer develop more stringent 
WQBELs.
    WQS are the foundation of the water quality-based pollution control 
programs required by the CWA. Such standards serve as a description of 
the desired water quality condition for particular waterbodies. In 
addition, WQS serve as the basis for several CWA programs, including:
     WQBELs in NPDES permits under section 402, 33 U.S.C. 1342;
     Waterbody assessments and establishment of total maximum 
daily loads (TMDLs) under section 303(d), 33 U.S.C. 1313(d);
     Certifications of Federal licenses and permits under 
section 401, 33 U.S.C., 1341.
    CWA section 303(c) directs states to adopt WQS for their waters 
subject to the CWA. WQS consist of designated uses of the waters, water 
quality criteria to protect those uses, and an antidegradation policy 
to maintain water quality (CWA section 303(c)(2)(A) and (d)(4)(B)). The 
EPA's regulation at 40 CFR 131.11(a)(1) provides that ``[s]uch criteria 
must be based on sound scientific rationale and must contain sufficient 
parameters or constituents to protect the designated use [and] [f]or 
waters with multiple use designations, the criteria shall support the 
most sensitive use.''
    States are required to review applicable WQS at least once every 
three years and, if appropriate, revise or adopt new WQS (CWA section 
303(c)(1) and 40 CFR 131.20). Any new or revised WQS must be submitted 
to the EPA for review and approval or disapproval (CWA section 
303(c)(2)(A) and (c)(3) and 40 CFR 131.20 and 131.21). Under CWA 
section 303(c)(4)(B), the Administrator is authorized to determine that 
a new or revised standard is necessary to meet CWA requirements.
    Under CWA section 304(a), the EPA is required to periodically 
publish national water quality criteria recommendations for states to 
consider when adopting water quality criteria for particular pollutants 
to meet the CWA section 101(a)(2) goals. In establishing numeric 
criteria, states should adopt water quality criteria based on the EPA's 
CWA section 304(a) criteria, section 304(a) criteria modified to 
reflect site-specific conditions, or other scientifically defensible 
methods (40 CFR 131.11(b)(1)). CWA section 303(c)(2)(B) requires states 
to adopt numeric criteria for all toxic pollutants listed pursuant to 
CWA section 307(a)(1) for which the EPA has published CWA section 
304(a) criteria, where the presence or discharge of those pollutants 
could reasonably be expected to interfere with maintaining designated 
uses.

B. Applicable Selenium Criteria in California

    The EPA has promulgated selenium water quality criteria for various 
waterbodies in California. First, in 1992, the EPA promulgated selenium 
criteria for certain California waters as part of the Water Quality 
Standards; Establishment of Numeric Criteria for Priority Toxic 
Pollutants; States' Compliance at 57 FR 60848, December 22, 1992, 
(hereafter referred to as the National Toxics Rule or NTR),\1\ and then 
again in 2000, as part of the Water Quality Standards; Establishment of 
Numeric Criteria for Priority Toxic Pollutants for the State of 
California at 65 FR 31681, May 18, 2000, (hereafter referred to as the 
California Toxics Rule or CTR).\2\ In each case, the EPA promulgated 
the EPA's recommended aquatic life criteria values at the time. In 
addition to the NTR and CTR selenium criteria, California has also 
adopted site-specific acute and chronic selenium criteria (California 
uses the term ``objectives'' instead of criteria). The criteria that 
the EPA previously promulgated for California in the NTR,\3\ together 
with the criteria promulgated in the CTR and California's site-specific 
objectives, established WQS for priority toxic pollutants for inland 
surface waters and enclosed bays and estuaries in California.
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    \1\ The NTR is codified at 40 CFR 131.36. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-D/part-131#131.36.
    \2\ The CTR is codified at 40 CFR 131.38. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-D/part-131/subpart-D/section-131.38.
    \3\ The CTR Criteria Table at 40 CFR 131.38(b)(1) includes all 
water quality criteria previously promulgated in the NTR, so that 
readers can find all Federally promulgated water quality criteria 
for California in one place. All criteria previously promulgated in 
the NTR are footnoted as such in the CTR.
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    For a full summary of the applicable selenium criteria covered by 
the NTR, the CTR, and California site-specific selenium objectives, 
please refer to the preamble of the EPA's proposed rulemaking for this 
action, sections II.B and II.C (83 FR 64059, December 13, 2018). For a 
discussion on the scope of

[[Page 101916]]

California waters covered by this rule, please see section V. of this 
preamble.

C. California Toxics Rule and Endangered Species Act Consultation

    As required by section 7 of the Endangered Species Act (ESA) (16 
U.S.C. 1531 et seq.), the EPA consulted with the U.S. Fish and Wildlife 
Service (FWS) and the U.S. National Marine Fisheries Service (NMFS) 
(collectively, the Services) concerning the EPA's proposed and final 
CTR. The EPA initiated consultation with the Services in 1994. In March 
2000, the Services issued a final Joint Biological Opinion. The final 
Joint Biological Opinion \4\ recorded commitments by the EPA to: (1) 
withhold promulgation of (i.e., reserve) the EPA's proposed acute \5\ 
freshwater aquatic life criterion for selenium in the final CTR; (2) 
revise the national CWA section 304(a) recommended acute and chronic 
aquatic life criteria for selenium; and (3) later update the acute and 
chronic aquatic life criteria for California consistent with the 
revised national CWA section 304(a) recommendations. As a result, in 
the May 2000 CTR, the EPA finalized the chronic freshwater selenium 
criterion \6\ and the acute and chronic saltwater selenium criteria but 
did not finalize the acute freshwater selenium criterion.
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    \4\ Final Joint Biological Opinion dated March 24, 2000, from 
the National Marine Fisheries Service, Long Beach, California, and 
the U.S. Fish and Wildlife Service, Sacramento, California, 
concerning EPA's final rule for the Promulgation of Water Quality 
Standards: Establishment of Numeric Criteria for Priority Toxic 
Pollutants for the State of California (CTR).
    \5\ The proposed freshwater acute selenium criterion in the CTR 
was as follows: The CMC = l/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 
are the fractions of total selenium that are treated as selenite and 
selenate respectively, and f1 + f2 = 1. CMC1 and CMC2 are the CMCs 
for selenite and selenate, respectively, or 185.9 [micro]g/L and 
12.83 [micro]g/L, respectively. This criterion was in the total 
recoverable form. CMC is the continuous maximum concentration.
    \6\ The final chronic criterion was based on the EPA's 1987 
national CWA section 304(a) recommended criterion.
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D. Litigation

    Section 303(c)(4)(B) of the CWA gives the EPA Administrator 
authority to promulgate water quality standards for a state where 
necessary to meet the requirements of CWA section 303. The EPA made an 
Administrator's determination under section 303(c)(4)(B) of the CWA, 
included in the 1997 proposed \7\ and 2000 final CTR, that numeric 
criteria are necessary in California to meet the requirements of 
section 303(c)(2)(B) to protect the State's designated uses.\8\ In 
2013, two organizations filed a complaint against the EPA in the United 
States District Court for the Northern District of California. The 
complaint was based in part on the fact that the EPA had previously 
determined, in the CTR, that selenium criteria were necessary to 
implement section 303(c)(2)(B) of the CWA (62 FR 42160, August 5, 1997) 
and the work to update the reserved freshwater acute selenium criterion 
from the 2000 CTR had not yet been completed. In 2014, the EPA entered 
into a consent decree to resolve these claims (Our Children's Earth 
Foundation and Ecological Rights Foundation v. U.S. Environmental 
Protection Agency, et al., 13-cv-2857 (N.D. Cal, August 22, 2014)).
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    \7\ Proposed California Toxics Rule, 62 FR 42160 (August 5, 
1997).
    \8\ See the CTR preamble at section E.1., ``EPA is using section 
303(c)(4)(B) as the legal basis for today's final rule.'' 65 FR 
31687 (May 18, 2000).
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    Under the terms of the consent decree, the EPA committed to 
proposing selenium criteria for California fresh waters covered by the 
original CTR to protect aquatic life and aquatic-dependent wildlife by 
November 30, 2018. On November 29, 2018, the EPA satisfied this 
commitment when the Administrator of the EPA signed the proposed 
rulemaking to establish a selenium water quality criterion applicable 
to California that protects aquatic life and aquatic-dependent wildlife 
in certain waters of California. The consent decree also required that 
the EPA request to initiation of any necessary ESA section 7(a)(2) 
consultation with the Services on the proposed selenium criteria no 
later than nine months after the date the EPA proposed the criteria. 
The EPA satisfied this commitment by initiating ESA consultation with 
the Services on the proposed selenium criterion on August 12, 2019.
    Further, under the consent decree, the EPA is required to finalize 
its proposed selenium criteria within six months of the later of the 
following: (1) the date of the EPA's conclusion (if any) that it will 
not seek ESA section 7(a)(2) consultation because some or all of the 
proposed selenium criteria have ``no effect'' on any listed ESA species 
or designated critical habitat; (2) the date of written concurrence 
from the Services with any EPA conclusion that some or all of the 
proposed selenium criteria are ``not likely to adversely affect'' 
listed ESA species or designated critical habitat; or (3) the date of 
the Services' Biological Opinion(s) concluding any formal consultation 
on the proposed selenium criteria.

E. Selenium and Sources of Selenium

    Selenium is a naturally occurring, but relatively rare, element 
present in sedimentary rocks and soils. It is also present in the 
atmosphere as methyl derivatives of selenium. There are around 40 known 
selenium-containing minerals, some of which can have as much as 30% 
selenium, but all are rare and generally occur together with sulfides 
of metals such as copper, zinc, and lead.\9\ The distribution of 
organic-enriched sedimentary rocks, black shales, petroleum source 
rocks, ore deposits, phosphorites, and coals, in which selenium 
typically co-occurs, is well characterized in the United States.\10\ 
Two major anthropogenic (i.e., human-caused) activities can cause 
selenium to become mobilized and introduced into aquatic systems. The 
first is extracting metals, minerals, and fossil fuels; the second is 
irrigation of selenium-rich soils. Once inorganic selenium is converted 
into a bioavailable form (i.e., a form that can be absorbed into the 
body following skin contact, ingestion, or inhalation), it enters the 
food chain and can bioaccumulate (i.e., can be taken up and retained by 
an aquatic organism from any surrounding media, e.g., water, food, 
sediment).
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    \9\ Emsley, John. October 2011. Nature's Building Blocks: An A-Z 
Guide to the Elements, 2nd Edition.
    \10\ Presser TS, Piper DZ, Bird KJ, Skorupa JP, Hamilton SJ, 
Detwiler Sj, Huebner MA. 2004. The Phosphoria Formation: a model for 
forecasting global selenium sources to the environment. In: JR Hein, 
editor. Life cycle of the phosphoria formation: From deposition to 
post-mining environment. New York (NY): Elsevier. P 299-319. See 
Figures 1 and 2.
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    Elevated selenium levels above what is nutritionally required in 
fish and other wildlife inhibit normal growth and reduce reproductive 
success through effects that lower embryo survival, most notably 
teratogenesis (i.e., embryo/larval deformities) (see 2021 Revision to: 
Final Aquatic Life Ambient Water Quality Criteria for Selenium--
Freshwater 2016, US EPA, Office of Water, EPA 822-R-21-006, August 
2021). The deformities associated with exposures to elevated selenium 
in fish may include skeletal, craniofacial, and fin deformities, and 
various forms of edema that result in mortality. Elevated selenium 
exposure in birds can reduce reproductive success including decreased 
fertility, reduced egg hatchability (embryo mortality), and increased 
incidence of deformities in embryos.
    Scientific studies \11\ indicate that selenium toxicity to aquatic 
life and

[[Page 101917]]

aquatic-dependent wildlife is driven by diet (i.e., the consumption of 
selenium-contaminated prey) rather than by direct exposure to dissolved 
selenium in the water column. Unlike other bioaccumulative 
contaminants, such as mercury, the single largest step in selenium 
accumulation in aquatic environments occurs at the base of the food web 
when algae and other particulate material take up selenium from water. 
The vulnerability of a species to selenium toxicity is determined by a 
number of factors, in addition to the amount of contaminated prey 
consumed. Those factors include a species' sensitivity to selenium, its 
population status, and the duration, timing, and life stage of 
exposure. In addition, the hydrologic conditions and water chemistry of 
a waterbody affect bioaccumulation; in general, slow-moving, calm 
waters or lentic waters enhance the production of bioavailable forms of 
selenium (selenite), while faster-moving waters or lotic waters limit 
selenium uptake by aquatic life and aquatic-dependent wildlife given 
the rapid movement and predominant form of selenium (selenate). The EPA 
considered these and other factors in determining the selenium 
criterion for California.
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    \11\ Scientific studies used in the development of this 
rulemaking can be found in this rule's docket, as well as dockets 
EPA-HQ-OW-2004-0019 and EPA-HQ-OW-2015-0392.
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III. Final Freshwater Chronic Selenium Criterion

A. The EPA's Approach

    In 2016, the EPA published a revised national CWA section 304(a) 
recommended chronic freshwater aquatic life criterion for selenium to 
better account for bioaccumulation through the food chain in different 
ecosystems, and published an erratum in 2021, 2021 Revision to: Final 
Aquatic Life Ambient Water Quality Criterion for Selenium--Freshwater 
2016, US EPA, Office of Water, EPA 822-R-21-006, August 2021.\12\ For 
purposes of clarity in this preamble, all subsequent references to the 
EPA's current national CWA section 304(a) recommended chronic 
freshwater criterion for selenium refers to its 2021 published version. 
The recommended chronic freshwater criterion is comprised of four 
criterion elements, two of which are fish tissue concentrations and two 
of which are water column concentrations. The recommended elements are: 
(1) a fish egg-ovary element of 15.1 milligram per kilogram (mg/kg) dry 
weight; (2) a fish whole-body element of 8.5 mg/kg dry weight or a 
muscle element of 11.3 mg/kg dry weight; (3) a water column element of 
3.1 [micro]g/L in lotic aquatic systems and 1.5 [micro]g/L in lentic 
aquatic systems; and (4) a water column intermittent exposure element 
derived from the chronic water column element to account for potential 
chronic effects from short-term exposures (one value for lentic and one 
value for lotic aquatic systems).
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    \12\ In 2021, the EPA identified that the following text was 
missing from the second sentence in footnote 4 in the selenium 
criterion table: ``When selenium inputs are increasing'' and issued 
an erratum. The EPA corrected footnote 4 to state: ``4. Water column 
values are based on dissolved total selenium in water and are 
derived from fish tissue values via bioaccumulation modeling. When 
selenium inputs are increasing, water column values are the 
applicable criterion element in the absence of steady-state 
condition fish tissue data.''
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    As stated previously, on November 29, 2018, the EPA Administrator 
signed the proposed rulemaking to establish a selenium water quality 
criterion that protects aquatic life and aquatic-dependent wildlife in 
certain fresh waters of California. The EPA proposed its recommended 
2016 CWA section 304(a) selenium criterion for freshwater with two 
modifications to the criterion. First, the EPA proposed adding a bird 
tissue criterion element derived to protect aquatic-dependent wildlife 
to the EPA's national CWA section 304(a) selenium criterion. Second, 
the EPA proposed replacing the EPA's national CWA section 304(a) 
selenium monthly average exposure water column (lentic or lotic) 
criterion element (referred to as the default water column criterion 
element) with a performance-based approach (PBA) for translating a 
tissue criterion element into a corresponding water column criterion 
element on a site-specific basis and took comment on whether to keep 
the default water column criterion element, in addition to the PBA, in 
the final rule.
    In this rule, the EPA considered the methodology and information 
used to derive the current national CWA section 304(a) recommended 
selenium criterion, additional information specific to aquatic-
dependent wildlife in California, and the public comments and feedback 
the EPA received on the proposed rulemaking in order to ensure broad 
protection for both aquatic and aquatic-dependent species. The final 
freshwater chronic selenium criterion for certain waters in California 
adds a bird tissue criterion element to the national CWA section 304(a) 
selenium criterion, consistent with the proposed rulemaking, in 
addition to the PBA. The EPA also included the default water column 
criterion element from the EPA's national CWA section 304(a) selenium 
criterion, in addition to the PBA in the final rule. The PBA will allow 
the State to develop a site-specific water column element to be used 
instead of the default water column criterion element. For a further 
discussion of the EPA's final chronic freshwater selenium criterion and 
what the EPA considered in finalizing this rule, see section III.C of 
this preamble and also refer to the EPA's Response to Comments document 
in the public docket for this rule.
    As mentioned previously, the chronic freshwater selenium criterion 
in this final rule will apply to California waters in a manner 
consistent with the CTR and the EPA's proposed rulemaking for this 
action (83 FR 64059, December 13, 2018).
    The promulgated criterion establishes levels of selenium that 
protect California's aquatic life and aquatic-dependent wildlife 
designated uses (California uses the term ``beneficial uses'' instead 
of designated uses) for certain waters of California consistent with 
California's implementation of the CTR. California's applicable 
designated (beneficial) uses for the protection of aquatic life and 
aquatic-dependent wildlife are listed in table 1 of this preamble.

                      Table 1--Applicable Designated (Beneficial) Uses for California \13\
----------------------------------------------------------------------------------------------------------------
                   Use                            Abbreviation                         Definition
----------------------------------------------------------------------------------------------------------------
Warm Freshwater Habitat.................  WARM.......................  Uses of water that support warm water
                                                                        ecosystems including, but not limited
                                                                        to, preservation or enhancement of
                                                                        aquatic habitats, vegetation, fish, or
                                                                        wildlife, including invertebrates.
Cold Freshwater Habitat.................  COLD.......................  Uses of water that support cold water
                                                                        ecosystems including, but not limited
                                                                        to, preservation or enhancement of
                                                                        aquatic habitats, vegetation, fish, or
                                                                        wildlife, including invertebrates.
Migration of Aquatic Organisms..........  MIGR.......................  Uses of water that support habitats
                                                                        necessary for migration or other
                                                                        temporary activities by aquatic
                                                                        organisms, such as anadromous fish.

[[Page 101918]]

 
Spawning, Reproduction, and/or Early      SPWN.......................  Uses of water that support high quality
 Development.                                                           aquatic habitats suitable for
                                                                        reproduction and early development of
                                                                        fish.
Estuarine Habitat.......................  EST........................  Uses of water that support estuarine
                                                                        ecosystems including, but not limited
                                                                        to, preservation or enhancement of
                                                                        estuarine habitats, vegetation, fish,
                                                                        shellfish, or wildlife (e.g., estuarine
                                                                        mammals, waterfowl, shorebirds).
Wildlife Habitat........................  WILD.......................  Uses of water that support terrestrial
                                                                        ecosystems including, but not limited
                                                                        to, preservation or enhancement of
                                                                        terrestrial habitats, vegetation,
                                                                        wildlife (e.g., mammals, birds,
                                                                        reptiles, amphibians, invertebrates), or
                                                                        wildlife water and food sources.
Rare, Threatened, or Endangered Species.  RARE.......................  Uses of water that support habitats
                                                                        necessary, at least in part, for the
                                                                        survival and successful maintenance of
                                                                        plant or animal species established
                                                                        under state or Federal law as rare,
                                                                        threatened or endangered.
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B. Administrator's Determination of Necessity
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    \13\ Refer to document titled ``Applicable Designated 
(Beneficial) Uses for California,'' in the docket associated with 
this rulemaking, to find designated uses captured in the California 
Regional Water Quality Control Boards' Water Quality Control Plans 
(i.e., Regional Boards' Basin Plans).
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    As previously noted, in the 1997 proposed and 2000 final CTR, the 
EPA Administrator determined under CWA section 303(c)(4)(B) that 
selenium criteria were necessary in California. In the 1997 proposed 
CTR, the EPA proposed both acute and chronic freshwater selenium 
criteria. In the 2000 final CTR, the EPA promulgated a chronic 
freshwater selenium criterion; withheld promulgation of (i.e., 
reserved) an acute freshwater selenium criterion; and committed to 
revising the national CWA section 304(a) recommended acute and chronic 
aquatic life criteria for selenium and later updating the acute and 
chronic aquatic life criteria for California consistent with the 
revised national CWA section 304(a) recommendations. The Services 
incorporated the EPA's commitments as Terms and Conditions in the final 
Joint Biological Opinion for the CTR.
    In November 2018, the EPA proposed a revised chronic selenium 
criterion based on the EPA's current national CWA section 304(a) 
recommended criterion for selenium, which only includes a chronic 
criterion. The EPA's current national CWA section 304(a) recommendation 
does not include a separate acute criterion because selenium is 
bioaccumulative and toxicity primarily occurs through dietary exposure. 
Although selenium may cause acute toxicity at high concentrations, the 
most harmful effect on aquatic organisms is due to its bioaccumulative 
properties; these chronic effects occur at lower concentrations of 
selenium in aquatic organisms than acute effects. In addition, as 
discussed further in section III.C of this preamble, application of the 
intermittent exposure criterion element (that the EPA is promulgating 
as part of the chronic criterion) to single day, high exposure events 
will provide protection from the most important selenium toxicity 
effect, reproductive toxicity, by protecting against selenium 
bioaccumulation in the aquatic ecosystem resulting from short-term, 
high exposure events. Since the time of the EPA's proposed rulemaking 
in November 2018, the EPA is not aware of any significant scientific 
updates to alter the scientific basis underlying the EPA's current 
national CWA section 304(a) recommended freshwater chronic selenium 
criterion. As a result, the EPA is not including a separate freshwater 
acute selenium criterion.
    Accordingly, promulgation of the freshwater chronic selenium 
criterion in this rule completes the EPA's action pursuant to the 
Administrator's Determination as it pertains to selenium criteria, as 
provided in the 1997 and 2000 preambles to the CTR.
    In addition, this promulgation satisfies the Services' Term and 
Condition included in the final Joint Biological Opinion for the CTR to 
update the selenium criterion for California consistent with the 
current national CWA section 304(a) recommendations (see section II.C. 
of this preamble). For more information about the ESA consultation 
completed for this final rule, see section IV. of this preamble.

C. Final Chronic Selenium Criterion for California's Fresh Waters

    In this final rule, the EPA is promulgating its current national 
CWA section 304(a) recommended chronic selenium criterion for certain 
fresh waters in California (including the default water column 
criterion element), with the addition of a bird tissue criterion 
element and a performance-based approach (PBA) \14\ for translating a 
tissue criterion element into a corresponding water column criterion 
element on a site-specific basis. In its proposed rulemaking, the EPA 
solicited comment on whether to replace the default water column 
criterion element from the Agency's 2016 CWA section 304(a) selenium 
criterion with the PBA, replace the PBA with the default water column 
criterion element from the Agency's 2016 CWA section 304(a) selenium 
criterion, or include both. As discussed further in this section and in 
the EPA's Response to Comments document in the public docket for this 
rule, the EPA is including both the default water column criterion 
element and the PBA in its promulgation of the chronic criterion; a 
site-specific water column value developed using the PBA may be used in 
place of the default (lentic or lotic) water column criterion element.
---------------------------------------------------------------------------

    \14\ A performance-based approach relies on the state or 
authorized Tribe adopting a process (i.e., a criterion derivation 
methodology, with associated implementation procedures) rather than 
a specific outcome (e.g., numeric criterion or concentration of a 
pollutant) in its water quality standards regulation. In instances 
where the EPA promulgates a water quality standard (including a 
performance-based approach) for a state or authorized Tribe, the EPA 
is held to the same policies, procedures, analyses, and public 
participation requirements for that water quality standard as the 
state or authorized Tribe. See 40 CFR 131.22(c). The concept of a 
performance-based approach was first described in the Federal 
Register document EPA Review and Approval of State and Tribal Water 
Quality Standards--Final Rule (65 FR 24641-24653; April 27, 2000).
---------------------------------------------------------------------------

    The final freshwater chronic selenium criterion for California is 
depicted in table 2 of this preamble.
    In the proposed rulemaking, the EPA solicited comment on two 
potential criteria structures: (1) one criterion that protects both the 
applicable aquatic life and aquatic-dependent wildlife designated uses; 
and (2) two separate criteria with one intended to protect the 
applicable aquatic life designated uses and one intended to protect the 
applicable aquatic-dependent wildlife designated uses. Most commenters 
requested that the EPA keep the proposed option of one criterion.

[[Page 101919]]

    After considering comments, the EPA is finalizing the rule as 
proposed, meaning that one criterion (with multiple criterion elements 
as shown in table 2 of this preamble) will be used to protect both 
aquatic life and aquatic-dependent wildlife designated uses in the 
waters covered by this rule. The one criterion consists of the 
following criterion elements: fish egg-ovary tissue, fish muscle or 
whole-body tissue, bird egg tissue, default water column (lentic and 
lotic), intermittent exposure water column, and a PBA for translating 
the tissue criterion elements into corresponding water column criterion 
elements on a site-specific basis.
    The tissue criterion elements consist of (1) a fish egg-ovary 
criterion element of 15.1 mg/kg dry weight, (2) a fish whole-body 
criterion element of 8.5 mg/kg dry weight or a fish muscle criterion 
element of 11.3 mg/kg dry weight, and (3) a bird egg criterion element 
of 11.2 mg/kg dry weight. The fish egg-ovary tissue (from which all 
other fish tissue elements were derived) and bird egg tissue criterion 
elements were developed to protect aquatic and aquatic-dependent 
wildlife populations from impacts caused by selenium: they reflect 
biological uptake of selenium through diet, which is the predominant 
pathway for selenium toxicity, and are most predictive of the observed 
biological endpoint of concern, reproductive toxicity.
    The water column criterion elements consist of (1) the default 
water column criterion element for lentic waters, 1.5 [micro]g/L, or 
for lotic waters, 3.1 [micro]g/L and (2) the intermittent exposure 
water column criterion element. In addition to the default water column 
criterion element, EPA is also promulgating the PBA Method for 
Translating Selenium Tissue Criterion Elements into Site-specific Water 
Column Criterion Elements for California, Version 2, December 2024, 
which is available in the docket for this rulemaking and incorporated 
by reference as part of this rule.
    The chronic selenium criterion applies to the entire aquatic 
community, including aquatic-dependent wildlife. Based on the analysis 
in the accompanying Technical Support Document (TSD) to this rule 
(FINAL Aquatic Life and Aquatic-Dependent Wildlife Selenium Water 
Quality Criterion for Freshwaters of California (December 2024)) and 
the EPA's previous work (2021 Revision to: Final Aquatic Life Ambient 
Water Quality Criterion for Selenium--Freshwater 2016, US EPA, Office 
of Water, EPA 822-R-21-006, August 2021), as well as currently 
available data, fish and birds are considered the most sensitive 
aquatic and aquatic-dependent taxa to selenium effects, respectively.
    The available data indicate that applying the criterion in table 2 
of this preamble would protect aquatic life and aquatic-dependent 
wildlife from the toxic effects of selenium, recognizing that the bird 
tissue criterion element is independently applicable from and 
equivalent to the fish tissue criterion elements; the fish egg-ovary 
criterion element supersedes all other fish tissue elements; the fish 
tissue criterion elements (egg-ovary, whole-body, and/or muscle) 
supersede water column criterion elements for aquatic life when fish 
tissue is measured; and the bird tissue criterion element supersedes 
water column criterion elements for aquatic-dependent wildlife when 
bird egg tissue is measured. This hierarchy reflects the fact that fish 
and bird tissue concentrations provide the most robust and direct 
information on potential selenium effects in fish and birds. See 
section III.D Implementation of the Final Chronic Selenium Criterion in 
California of this preamble for the discussion regarding implementation 
of the final chronic selenium criterion and one exception to the 
hierarchy described above when selenium inputs are increasing.
    The EPA is promulgating the following chronic criterion in new 
paragraph (b)(1)(i) of 40 CFR 131.38. The EPA is also making revisions 
to footnote q in the criteria table in paragraph (b)(1) and clarifying 
edits regarding the applicability of this criterion in paragraphs 
(c)(3)(ii) and (iii). The EPA is not amending or revising the contents 
of the table in (b)(1) and language in 40 CFR 131.38, except as 
specified in the preceding two sentences.

[[Page 101920]]

[GRAPHIC] [TIFF OMITTED] TR17DE24.066


[[Page 101921]]


Performance-Based Approach (PBA) for Translating Tissue Criterion 
Elements to Site-Specific Water Column Criterion Elements
    As part of the criterion depicted in table 2 of this preamble, the 
EPA is incorporating by reference the PBA, Method for Translating 
Selenium Tissue Criterion Elements into Site-specific Water Column 
Criterion Elements for California, Version 2, December 2024. The PBA is 
a methodology that the State may use to translate the bird and fish 
tissue criterion elements into water column criterion elements on a 
site-specific basis.
    If the State chooses to use the PBA, the State will coordinate with 
the EPA at the beginning of the process. The PBA is itself incorporated 
by reference into this rule and thus is part of the applicable WQS that 
the EPA is promulgating. As such, California is not required to adopt 
and submit the outcomes that result from using the PBA (i.e., water 
column criterion elements for site-specific waterbodies) to the EPA for 
CWA section 303(c) review. In this rule, the EPA is promulgating the 
PBA as a scientifically defensible methodology that is sufficiently 
detailed and has suitable safeguards to ensure predictable, repeatable 
outcomes that will protect California's applicable beneficial uses. If 
California chooses to use the PBA for a particular site, each resulting 
site-specific water column criterion element would be applicable for 
CWA purposes, without the need for separate EPA approval under CWA 
section 303(c).
    The PBA provides two methodologies for deriving a site-specific 
water column criterion element: (1) the mechanistic modeling approach; 
and (2) the empirical bioaccumulation factor (BAF) approach:
    (1) The mechanistic modeling approach uses scientific knowledge of 
the physical and chemical processes underlying bioaccumulation to 
establish a relationship between the concentrations of selenium in the 
water column and the concentration of selenium in the tissue of aquatic 
and aquatic-dependent organisms. This approach enables formulation of 
site-specific models of trophic transfer of selenium through aquatic 
food webs and translation of the tissue elements into an equivalent 
site-specific water column element. It is also the approach the EPA 
used to develop the national CWA section 304(a) recommended selenium 
water column criterion elements.
    (2) The empirical BAF approach establishes a site-specific 
relationship between water column selenium concentrations and fish or 
bird tissue selenium concentrations by measuring both directly and 
using the relationship between the concentrations to determine a site-
specific water column criterion element.
    As stated in footnote 5 of criterion, the default water column 
criterion element, consisting of a water column value of 1.5 [micro]g/L 
dissolved total selenium in lentic aquatic systems and 3.1 [micro]g/L 
dissolved total selenium in lotic aquatic systems, applies for all CWA 
purposes according to the hierarchy of the criterion, unless a site-
specific water column criterion element is derived following the PBA.
    If California decides to use the PBA to translate the applicable 
fish tissue or bird tissue criterion elements into site-specific water 
column criterion elements, those translated values would be applicable 
for, and protective of, the use for which the translation was 
completed. For example, if California used the PBA to translate the 
fish tissue criterion element into a water column criterion element, 
that water column criterion element would protect aquatic life; if 
California used the PBA to translate the bird tissue criterion element 
into a water column criterion element, that water column criterion 
element would protect aquatic-dependent wildlife.
    The EPA looks forward to coordinating and working with the State to 
ensure consistency with the PBA methodology before implementation in 
other CWA programs. Importantly, for public transparency, the EPA 
recommends California maintain a list of the resulting site-specific 
water column criterion elements. The EPA also recommends that 
California make its analyses and the underlying data used for each 
site-specific water column derivation available on a publicly 
accessible State website.
    As with other criteria, the State maintains discretion to adopt new 
or revised site-specific criteria and submit them to the EPA in 
accordance with CWA section 303(c) and EPA's implementing regulations 
at 40 CFR part 131. This could arise in the context of an entirely 
different criterion, an alternative water column criterion element, or 
an alternative tissue to water column derivation methodology. Please 
refer to section VI, Conditions When Federal Standards Would Be 
Withdrawn of this preamble for a discussion regarding the applicability 
of California-adopted, EPA-approved WQS in light of this Federal 
promulgation.
    If the State chooses not to follow the PBA as prescribed, the State 
would need to adopt and submit site-specific water column criterion 
elements to the EPA for CWA section 303(c) review and approval in 
accordance with the procedures at 40 CFR part 131 in order to rely on 
them as applicable WQS for other CWA programs such as the TMDL and 
NPDES permitting programs. This is because the new value would not 
derive from or comply with applicable WQS (see 40 CFR 122.44(d)).\15\
---------------------------------------------------------------------------

    \15\ 82 FR 25628, April 27, 2000.
---------------------------------------------------------------------------

    In the proposed rulemaking, the EPA took comment on whether the 
national CWA section 304(a) recommended water column criterion element 
(lentic and lotic) should be included as a default, in addition to or 
in place of the PBA, in the final selenium criterion. Most commenters 
supported including the PBA in the final rule, and some requested that 
the default water column criterion element not be included in the final 
rule. However, several comments highlighted implementation concerns, 
such as gaps in protection before the PBA can be used to develop site-
specific water column criterion elements, anticipated burdens on 
industry to rely on the PBA to derive site-specific water column 
criterion elements, and new discharger considerations that could be 
mitigated by including the default water column criterion element, in 
addition to the PBA.
    In consideration of these public comments and to maintain 
consistency with the EPA's latest scientific recommendation to ensure 
protection of aquatic life and aquatic-dependent wildlife from exposure 
to toxic levels of selenium, as articulated in the EPA's current 
national CWA section 304(a) recommended freshwater aquatic life 
criterion for selenium and the TSD accompanying this final rule, the 
EPA decided to include the default water column criterion element as 
part of the California selenium criterion for the final rule, in 
addition to the PBA. This will ensure protection from excessive 
selenium in certain waters in California when tissue data are 
unavailable. Specifically, water column data and criterion elements can 
be applied for CWA implementation purposes when tissue data are 
unavailable. When all of the criterion elements are applied together, 
the tissue and water column criterion elements protect aquatic life and 
aquatic-dependent wildlife from the chronic effects of exposure to 
selenium in waterbodies. This will also help ensure that California is 
able to implement the Federally promulgated selenium criterion as soon 
as it is effective under the CWA.
    The EPA also specifically solicited comment on whether it would be

[[Page 101922]]

appropriate to include a method for a larger scale (e.g., ecoregional 
or state-wide) water column translation from fish or bird egg tissue in 
the PBA, and if so, what methods are available and appropriate for this 
large-scale translation. Most commenters agreed that a larger-scale 
translation method was not appropriate, finding the PBA was more 
appropriate and scientifically defensible on a waterbody site-specific 
scale, given the highly localized conditions that affect selenium 
bioaccumulation. After taking into consideration all comments, EPA 
decided to keep the allowable application of the PBA limited to an 
individual waterbody or waterbody segment. Developing a water column 
translation for a larger geographic area involves additional 
considerations that are not included in the PBA. These additional 
considerations are likely unique to the geographic area and would be 
better addressed through an individual site-specific criteria process 
by the State. California retains the ability to develop a site-specific 
criterion for a larger site, such as a watershed or ecoregion. Any such 
state-adopted, site-specific criterion must be submitted to the EPA for 
review and approval pursuant to CWA section 303(c) and the EPA's 
implementing regulations at 40 CFR part 131 to be effective for CWA 
purposes.
    The EPA intends for the PBA to be severable from the remainder of 
the final selenium criterion in this rule. As explained above, the EPA 
has chosen to promulgate the PBA as part of the criterion, providing 
one means for the State to translate the bird and fish tissue criterion 
elements into water column criterion elements on a site-specific basis. 
The EPA included the PBA in this final rule to provide an efficient 
means to account for site-specific information to inform the applicable 
water column criterion element. The removal of the PBA would not change 
how the overall rule functions. The final selenium criterion protects 
aquatic life and aquatic-dependent wildlife through the applicable 
tissue and water column criterion elements for all the specified waters 
in California. In contrast, as discussed above, California's use of the 
PBA in the final rule is optional and not mandatory. As such, the 
tissue and water column criterion elements apply independently of the 
PBA and function separately to meet the requirements of CWA section 
303(c). In the absence of the PBA, the other criterion elements of the 
final selenium criterion will still protect the designated uses for 
aquatic life and aquatic-dependent wildlife in accordance with CWA 
section 303(c) and the EPA's implementing regulations. In other words, 
the final selenium criterion, with the criterion elements absent the 
PBA, still functions as the applicable criterion to protect the 
designated uses. Further, California could pursue other options in lieu 
of using the PBA to adopt site-specific selenium criteria. For example, 
as with other criteria, the State maintains discretion to adopt new or 
revised site-specific criteria and submit them to the EPA in accordance 
with CWA section 303(c) and the EPA's implementing regulations at 40 
CFR part 131. Accordingly, the EPA intends this portion of the rule to 
be severable from the remainder of the rule.
Intermittent Exposure Criterion Element
    Although selenium may cause acute toxicity at high concentrations 
(i.e., toxicity from a brief but highly elevated concentration of 
selenium in the water), chronic dietary exposure poses the highest risk 
to aquatic life and aquatic-dependent wildlife. Chronic toxicity occurs 
primarily through maternal transfer of selenium to eggs and causes 
subsequent reproductive effects, such as larval and embryo structural 
deformity, edema, and mortality. Because chronic effects of selenium 
are observed at lower concentrations than acute effects, the chronic 
criterion is expected to protect aquatic and aquatic-dependent 
communities from any potential acute effects of selenium. However, some 
high concentration, short-term exposures could be detrimental by 
causing significant long-term, residual, bioaccumulative effects (i.e., 
by the introduction of elevated selenium load into the system). 
Therefore, the EPA is also promulgating the intermittent exposure 
criterion element within the chronic criterion to prevent long-term 
detrimental effects from these high concentration, short-term 
exposures.
    The EPA's intermittent exposure criterion element is derived 
mathematically from either the default water column criterion element 
or the performance-based, site-specific monthly water column criterion 
element, using the equation shown in Table 2 of this preamble. The 
equation expresses the intermittent exposure water column criterion 
element in terms of the 30-day default water column criterion element, 
as appropriate, while accounting for the fraction in days of any 30-day 
period the intermittent spikes occur and for the background 
concentration occurring during the remaining time. The intermittent 
exposure criterion element calculation is consistent with the EPA's 
current national CWA section 304(a) recommended chronic freshwater 
aquatic life criterion for selenium. It is meant to be used in 
situations where a noncontinuous discharge containing selenium is 
present in the waterbody of interest.

D. Implementation of the Final Chronic Selenium Criterion in California

    Identification of Impaired Waters and TMDL Development
    WQS provide the basis for identifying impaired waters (waters not 
attaining the applicable WQS) and developing TMDLs pursuant to CWA 
section 303(d). With the promulgation of this multi-element criterion, 
all criterion elements will be available for assessment purposes. If 
multiple types of data are collected at a site, they will be used for 
implementation purposes according to the hierarchical structure of the 
selenium criterion. For purposes of assessing attainment of the WQS 
based on the criterion and as mentioned in section III.C of this 
preamble, the bird tissue criterion element is independently applicable 
from the fish tissue criterion elements. Specifically, if the bird 
tissue criterion element is exceeded, the criterion is not being 
attained for the applicable aquatic-dependent wildlife designated uses, 
and if the fish tissue criterion element is exceeded (using the 
hierarchy for fish tissue), the criterion is not being attained for the 
applicable aquatic life designated uses. For aquatic-dependent 
wildlife, the bird egg tissue element supersedes the water column 
elements if both are measured. For aquatic life, the fish egg-ovary 
tissue criterion element supersedes the muscle or whole-body criterion 
elements and all fish tissue criterion elements supersede water column 
criterion elements. However, there is one exception to this hierarchy. 
When selenium is increasing due to new inputs, footnote 4 of the 
criterion specifies that the water column criterion elements must be 
used when steady-state fish or bird tissue data are not available for 
each respective use, as discussed further below. Also, the default 
water column criterion element applies for CWA purposes for each 
respective designated use unless site-specific water column criterion 
elements are derived following the methodology described in the PBA, or 
site-specific water column criterion elements that do not follow the 
methodology prescribed by the PBA are adopted by California and 
approved by the EPA pursuant to CWA section 303(c) and the EPA's 
implementing regulations.

[[Page 101923]]

    Selenium concentrations in fish and bird tissue are primarily a 
result of selenium bioaccumulation via dietary exposure. In both the 
EPA's current national CWA section 304(a) recommended aquatic life 
criterion for selenium and this California selenium rulemaking, steady-
state refers to conditions where sufficient time has passed after the 
introduction of a new or increased input of selenium into a waterbody 
or watershed of a waterbody such that fish tissue concentrations of 
selenium are no longer increasing in the long-term average or multi-
year average. For a tissue measurement to be meaningful, the water from 
which the sample is taken should not be experiencing or have recently 
experienced new inputs of selenium. When there are new selenium inputs 
to a waterbody, fish tissue data and bird tissue data may not fully 
represent the potential effects on the aquatic ecosystem, making the 
use of the water column criterion elements more appropriate to protect 
the entire aquatic ecosystem. New inputs are defined as new 
anthropogenic activities resulting in the release of selenium into a 
lentic or lotic aquatic system.\16\ These ``new inputs'' are both new 
and increased inputs of selenium and are referring to the release of a 
substantial amount of additional selenium from either anthropogenic 
point or nonpoint sources into a waterbody or watershed. New inputs do 
not refer to seasonal variability of selenium that occurs naturally 
within a system (e.g., spring run-off events or precipitation-driven 
pulses) or de minimis inputs to a watershed or waterbody.\17\
---------------------------------------------------------------------------

    \16\ USEPA. 2021. 2021 Revision to: Aquatic Life Ambient Water 
Quality Criterion for Selenium-Freshwater 2016. EPA 822-R-21-006. 
U.S. Environmental Protection Agency, Office of Water, Washington, 
DC. https://www.epa.gov/system/files/documents/2021-08/selenium-freshwater2016-2021-revision.pdf.
    \17\ USEPA. 2024. Technical Support for Adopting and 
Implementing the EPA's 2016 Selenium Criterion in Water Quality 
Standards. EPA-820-R-24-001. U.S. Environmental Protection Agency, 
Office of Water, Washington, DC. https://www.epa.gov/system/files/documents/2024-03/selenium-adopting-tsd.pdf.
---------------------------------------------------------------------------

    The water column criterion elements take precedence over the fish 
tissue criterion elements and the bird egg tissue criterion element 
until tissue data have returned to a steady-state condition after a new 
input of selenium. In the interim, in systems with new inputs, the EPA 
recommends California sample tissue and water and use site-specific 
data to gain a better understanding of the selenium bioaccumulation 
dynamics in a receiving water and to determine if and when steady-state 
conditions have been reached.
    California has flexibility to determine how to evaluate individual 
and composite samples for each taxon. Tissue data provide instantaneous 
point measurements that reflect integrative accumulation of selenium 
over time and space in fish or birds at a given site. This final 
selenium criterion provides California with flexibility in how the 
State can interpret a discrete bird egg or fish tissue sample to 
represent a given species' population at a site. Generally, fish and 
bird egg tissue samples collected to calculate average tissue 
concentrations (often in composites) for a species at a site are 
collected during one sampling event, or over a short interval due to 
logistical constraints and the cost for obtaining samples. The State 
should clearly describe its decision-making process in its assessment 
methodology.
NPDES Permitting
    Under the CWA, WQS are used to derive WQBELs in NPDES permits for 
point source discharges, thereby limiting the amount of pollutants that 
may be discharged into a waterbody to attain and maintain its 
designated uses. The EPA is promulgating the default water column 
criterion element and the option for California to use the PBA to 
translate tissue criterion elements into site-specific water column 
criterion elements, which can be used to facilitate implementation, 
e.g., NPDES permitting. However, these water column criterion elements 
would not prevent California from also using the tissue criterion 
elements for monitoring and regulating pollutant discharges where 
appropriate.
    As with assessments, all criterion elements are available for NPDES 
permitting. When multiple data types are available for making 
permitting decisions, the hierarchy of the criterion will determine 
which data type will take precedence. In addition, as described above, 
when selenium is increasing due to new inputs, footnote 4 of the 
criterion specifies that the water column criterion elements must be 
used when steady-state fish or bird tissue data are not available.
    When implementing the selenium criterion under the NPDES permits 
program, California may need to establish additional implementation 
procedures due to the unique components of the selenium criterion. 
Where California uses a water column criterion element only (as opposed 
to using both the water column and fish tissue or bird tissue criterion 
elements) for conducting reasonable potential determinations and 
establishing WQBELs per 40 CFR 122.44(d), it may be appropriate for the 
State to evaluate existing implementation procedures for other water 
column aquatic life criteria. However, if California also decides to 
use the selenium fish tissue criterion elements and bird tissue 
criterion elements for NPDES permitting purposes, additional State WQS 
implementation procedures will likely be needed to determine the need 
for and development of WQBELs necessary to ensure that the tissue 
criterion element(s) are met.

E. Incorporation by Reference

    The regulatory text incorporates one EPA document by reference, 
specifically, the EPA's Method for Translating Selenium Tissue 
Criterion Elements into Site-specific Water Column Criterion Elements 
for California, Version 2, December 2024, discussed in section III.C of 
this preamble. The EPA has made, and will continue to make, this 
document available electronically at its website (https://www.epa.gov/wqs-tech/water-quality-standards-establishment-numeric-criterion-selenium-fresh-waters-california) and through www.regulations.gov at 
the docket associated with this rulemaking.

IV. Endangered Species Act

    Section 7(a)(2) of the ESA requires that each Federal agency ensure 
that any action authorized, funded, or carried out by such agency is 
not likely to jeopardize the continued existence of any endangered or 
threatened species or result in the destruction or adverse modification 
of critical habitat. For this rule, the EPA transmitted a Biological 
Evaluation to NMFS and FWS on November 23, 2022.
    On June 21, 2024, the EPA received a final Biological Opinion from 
FWS that determined that the EPA's action is likely to adversely affect 
but will not jeopardize the continued existence of bonytail, razorback 
sucker, Santa Ana sucker, tidewater goby, unarmored threespine 
stickleback, arroyo toad, California red-legged frog, foothill yellow-
legged frog, light-footed Ridgway's rail, Yuma Ridgway's rail, and 
California least tern. FWS also concurred with the EPA that the action 
may affect but is not likely to adversely affect the other Federally 
listed species and designated critical habitats for all species that 
were included in the consultation, including the longfin smelt for 
which the FWS provided supplemental concurrence with the EPA on October 
29, 2024, that the action may

[[Page 101924]]

affect but is not likely to adversely affect that species.\18\
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    \18\ FWS proposed to list the San Francisco Bay-Delta distinct 
population segment of longfin smelt as an endangered species on 
October 7, 2022 (87 FR 60957) and finalized the rule on July 30, 
2024 (89 FR 61029) with an effective date of August 29, 2024. The 
San Francisco Bay-Delta distinct population segment of longfin smelt 
had not been identified as part of the consultation in the EPA's 
biological evaluation or the FWS's Biological Opinion that the EPA 
received on June 21,2024, before the final rule was signed. As such, 
the EPA worked with FWS to address this species listing prior to 
signing the final rule.
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    On August 28, 2024, the EPA received a final Biological Opinion 
from NMFS that determined that the EPA's action is likely to adversely 
affect but will not jeopardize the continued existence of Central 
California Coast coho salmon, Southern Oregon/Northern California Coast 
coho salmon, Southern California steelhead, Central Valley steelhead, 
Northern California steelhead, Central California Coast steelhead, 
South-Central California Coast steelhead, Sacramento River winter-run 
Chinook salmon, Central Valley spring-run Chinook salmon, Central 
California Coast Chinook salmon, the Southern distinct population 
segment of North American green sturgeon, nor is the proposed action 
likely to result in the destruction or adverse modification of critical 
habitat for these species. NMFS also concurred with the EPA that the 
action may affect but is not likely to adversely affect the other 
Federally listed species and the designated critical habitat for the 
other species that were included in the consultation.
    The EPA's receipt of these final Biological Opinions and 
concurrences from the Services concludes the consultation for this rule 
under ESA section 7(a)(2). Documents associated with this ESA 
consultation are available in the docket associated with this rule 
(Docket ID: EPA-HQ-OW-2018-0056).

V. Applicability of the EPA-Promulgated Water Quality Standards

    This final rule for a chronic selenium freshwater criterion applies 
to certain waters of California in a manner consistent with the CTR 
where the protection of aquatic life and aquatic-dependent wildlife are 
designated uses, which includes the waters of the San Luis National 
Wildlife Refuge and the Los Banos State Wildlife Refuge.
    The final rule does not apply to California waters where site-
specific selenium criteria have been adopted, nor does it apply to 
California waters where selenium criteria have been promulgated in the 
NTR. In other words, this final rule does not apply to waters of the 
San Francisco Bay upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta, the San Joaquin River from Sack Dam to 
Vernalis, Mud Slough (north), Salt Slough, or constructed and 
reconstructed water supply channels in the Grassland watershed listed 
in Appendix 40 of the Central Valley Regional Water Quality Control 
Board's Basin Plan because these waters have applicable selenium 
criteria from the NTR and/or approved Central Valley Regional Water 
Quality Control Board site-specific objectives.
    Lastly, the final rule does not apply to surface waters that are 
tributaries to the Salton Sea because California adopted, and EPA-
approved, site-specific water quality objectives for these waters.
    As noted previously, this action adds clarifying language to the 
regulatory provisions regarding applicability of the CTR based on the 
salinity level of the waterbody in paragraphs (c)(3)(ii) and (iii) of 
40 CFR 131.38. The added language is not intended to affect the 
substance of those applicability provisions.
    The State of California has nine Regional Water Quality Control 
Boards (Regional Boards), each located in and overseeing different 
areas of the State. Each Regional Board has a regional water quality 
control plan (Basin Plan) that sets forth EPA-approved designated 
(beneficial) uses for the waterbodies it oversees. The criterion will 
become the applicable CWA-effective criterion for CWA implementation 
purposes by each of the Regional Boards after the effective date of 
this rule (i.e., 30 days after the date of publication of this rule in 
the Federal Register).

VI. Conditions When Federal Standards Would Be Withdrawn

    Under the CWA, Congress gave states the primary responsibility for 
developing and adopting WQS for their waters (CWA section 303(a) 
through (c)). Although the EPA is promulgating a selenium criterion for 
the protection of aquatic life and aquatic-dependent wildlife for 
certain waters of California, California continues to have the option 
to adopt and submit to the EPA selenium criteria for the State's waters 
consistent with CWA section 303(c) and the EPA's implementing 
regulations at 40 CFR part 131.
    If California adopts and submits selenium criteria for the 
protection of aquatic and aquatic-dependent wildlife for California 
(fresh water and/or salt water), the EPA will approve California's 
criteria if those criteria meet the requirements of section 303(c) of 
the CWA and the EPA's implementing regulation at 40 CFR part 131. If 
the EPA's Federally promulgated criteria are more stringent than the 
State's criteria, the EPA's Federally promulgated criteria are and will 
be the applicable water quality standard for purposes of the CWA until 
the EPA withdraws those Federally promulgated standards. The EPA would 
expeditiously undertake such a rulemaking to withdraw the Federal 
criteria if and when California adopts and the EPA approves 
corresponding criteria. After the EPA's withdrawal of Federally 
promulgated criteria, the State's EPA-approved criteria would become 
the applicable criteria for CWA purposes. If the State's adopted 
criteria are as stringent or more stringent than the Federally 
promulgated criteria, then the State's criteria would become the CWA 
applicable WQS upon the EPA's approval (40 CFR 131.21(c)).

VII. Alternative Regulatory Approaches

    The EPA's WQS regulation at 40 CFR part 131 provides several tools 
that California has available to use at its discretion when 
implementing or deciding how to implement this selenium criterion. 
Among other things, the EPA's regulation: (1) specifies how states and 
authorized Tribes \19\ establish, modify or remove designated uses; (2) 
specifies the requirements for establishing criteria to protect 
designated uses, including criteria modified to reflect site-specific 
conditions; (3) specifies the requirements for states and authorized 
Tribes to adopt WQS variances that provide time to achieve the 
applicable WQS; and (4) allows states and authorized Tribes to 
authorize the use of compliance schedules in NPDES permits to meet 
WQBELs derived from the applicable WQS. Each of these approaches are 
discussed in more detail in the next sections of this preamble.
---------------------------------------------------------------------------

    \19\ For purposes of this rule, an Indian Tribe that obtains EPA 
approval to administer a WQS program under CWA section 303(c) for 
its reservation is referred to as an ``authorized Tribe.''
---------------------------------------------------------------------------

Designated Uses
    The EPA's action applies to certain waters of California where the 
protection of aquatic life and aquatic-dependent wildlife are 
designated uses. The regulation at 40 CFR 131.10 provides information 
on establishing, modifying, and removing designated uses. If California 
removes designated uses such that no aquatic life or aquatic-dependent 
wildlife uses apply to any particular waterbody or waterbody segment 
affected by this rule and adopts the highest attainable use,\20\ the 
State

[[Page 101925]]

must also adopt criteria to protect the newly designated highest 
attainable use consistent with 40 CFR 131.11. It is possible that 
criteria other than the Federally promulgated criteria would protect 
the highest attainable use. If the EPA were to find removal or 
modification of the designated use and the adoption of the highest 
attainable use and criteria to protect that use is consistent with CWA 
section 303(c) and the implementing regulations at 40 CFR part 131, the 
EPA would approve the revised WQS. The EPA would then undertake a 
rulemaking to withdraw the corresponding Federally promulgated WQS for 
the relevant water(s).
---------------------------------------------------------------------------

    \20\ If a state or authorized Tribe adopts a new or revised WQS 
based on a use attainability analysis, then it must also adopt the 
highest attainable use (40 CFR 131.10(g)). Highest attainable use is 
the modified aquatic life, wildlife, or recreation use that is both 
closest to the uses specified in section 101(a)(2) of the Act and 
attainable, based on the evaluation of the factor(s) in 40 CFR 
131.10(g) that preclude(s) attainment of the use and any other 
information or analyses that were used to evaluate attainability. 
There is no required highest attainable use where the state 
demonstrates the relevant use specified in section 101(a)(2) of the 
Act and sub-categories of such a use are not attainable (see 40 CFR 
131.3(m)).
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Site-Specific Criteria
    The regulation at 40 CFR 131.11 specifies requirements for 
modifying water quality criteria to reflect site-specific conditions. 
In the context of this rulemaking, a site-specific criterion (SSC) is 
an alternative value to the Federal selenium criterion that would be 
applied on an area-wide or waterbody-specific basis that meets the 
regulatory test of protecting the designated uses, being scientifically 
defensible, and ensuring the protection and maintenance of downstream 
WQS. In this context, as discussed in section III.C of this preamble, 
SSC are different than a site-specific water column criterion element 
developed through the PBA incorporated by reference in this final rule. 
A SSC may be more or less stringent than the otherwise applicable 
Federal criterion. A SSC may be called for when further scientific data 
and analyses indicate that a different selenium concentration (e.g., a 
different fish tissue or bird tissue criterion element) may be needed 
to protect the aquatic life and aquatic-dependent wildlife-related 
designated uses in a particular waterbody or portion of a waterbody. 
Any such state-adopted SSC will need to be submitted to the EPA for 
review and approval pursuant to CWA section 303(c) and the EPA's 
implementing regulation at 40 CFR part 131.
WQS Variances
    California's WQS provide sufficient authority to apply WQS 
variances when implementing a Federally promulgated criterion for 
selenium, as long as such WQS variances are adopted consistent with 40 
CFR 131.14 and submitted to the EPA for review and approval under CWA 
section 303(c). The EPA's regulation at 40 CFR 131.3(o) defines a WQS 
variance as a time-limited designated use and criterion, for a specific 
pollutant or water quality parameter, that reflects the highest 
attainable condition during the term of the WQS variance. WQS variances 
adopted in accordance with 40 CFR 131.14 (including a public hearing 
consistent with 40 CFR 131.20(b)) provide a flexible but defined 
pathway for states and authorized Tribes to meet their NPDES permit 
obligations by allowing dischargers the time they need (as demonstrated 
by the state or authorized Tribe) to make incremental progress toward 
meeting WQS that are not immediately attainable but may be in the 
future. When adopting a WQS variance, states and authorized Tribes 
specify the interim requirements of the WQS variance by identifying a 
quantitative expression that reflects the highest attainable condition 
during the term of the WQS variance, establishing the term of the WQS 
variance, and describing the pollutant control activities expected to 
occur over the specified term of the WQS variance.
    WQS variances help states and authorized Tribes focus on improving 
water quality, rather than pursuing a downgrade of the underlying water 
quality goals through modification or removal of a designated use, as a 
WQS variance cannot lower currently attained water quality. NPDES 
permit limits can be written to comply with the WQS variance rather 
than the underlying WQS for the specified term of the WQS variance. If 
dischargers are still unable to meet the WQBELs derived from the 
applicable WQS once a WQS variance term is complete, the state or 
authorized Tribe may adopt a subsequent WQS variance if adopted 
consistent with 40 CFR 131.14.
Compliance Schedules
    The EPA's regulation at 40 CFR 122.47 allows permitting authorities 
to include compliance schedules in their NPDES permits, when 
appropriate and where authorized by the state or authorized Tribe. The 
EPA's regulation at 40 CFR 131.15 requires that states and authorized 
Tribes that choose to allow the use of NPDES permit compliance 
schedules adopt specific provisions authorizing their use and obtain 
EPA approval under CWA section 303(c) to ensure that a decision to 
allow permit compliance schedules is transparent and allows for public 
input (80 FR 51022, August 21, 2015). The EPA's approval of a state or 
authorized Tribe's permit compliance schedule authorizing provision as 
a WQS pursuant to 40 CFR 131.15 ensures that any NPDES permit that 
contains a compliance schedule meets the requirement that the level of 
water quality to be achieved by the WQBEL derive from and comply with 
all applicable WQS (40 CFR 122.44(d)(1)(vii)(A)).
    California is authorized to administer the NPDES program and has 
adopted several mechanisms to specify compliance schedules in NPDES 
permits. In 2008, California adopted a statewide compliance schedule 
authorizing provision that the EPA subsequently approved under CWA 
section 303(c), the Policy for Compliance Schedules in National 
Pollutant Discharge Elimination System Permits, State Water Resources 
Control Board Resolution No. 2008-0025, April 15, 2008. This EPA-
approved regulation authorizes the use of permit compliance schedules 
consistent with 40 CFR 131.15, and is not affected by this rule. The 
compliance schedule authorizing provision will allow California, as the 
permitting authority, to specify compliance schedules in permits, as 
appropriate, for the purpose of achieving compliance with a WQBEL based 
on the selenium criterion promulgated in this final rule, which is more 
stringent than the existing criteria for California, as soon as 
possible.

VIII. Economic Analysis

    To best inform the public of the potential impacts of this rule, 
the EPA evaluated the potential costs associated with State 
implementation of the EPA's selenium criterion based on available 
information. This analysis is documented in Economic Analysis for the 
Final Selenium Water Quality Criterion for the State of California, 
which can be found in the docket for this rule. For this analysis, the 
EPA assumed that California fully implements its existing selenium 
criteria (i.e., ``baseline criteria'') and estimated the incremental 
impacts for compliance with the selenium criterion in this rule. To 
facilitate this analysis, the EPA interpreted the criterion as the 
default water column criterion element (i.e., a lentic and lotic value) 
from the EPA's current CWA section 304(a) selenium criterion for fresh 
water. For point source costs, the EPA assumed any NPDES-permitted 
facility that

[[Page 101926]]

discharges selenium would have reasonable potential and would be 
subject to effluent limits and would incur compliance costs if it chose 
to continue discharging. The EPA also evaluated nonpoint sources that 
contribute selenium loadings to waters that would be considered 
impaired for selenium under the final criterion and evaluated whether 
they would incur incremental costs for additional best management 
practices. The total annualized cost of this final rule was estimated 
to range from $28.34 million to $44.84 million at a 2% discount rate. 
See Economic Analysis for the Final Selenium Water Quality Criterion 
for the State of California for a detailed summary of the information 
and assumptions the EPA relied on to estimate potential costs to 
implement the final rule.

IX. Statutory and Executive Orders

A. Executive Order 12866 (Regulatory Planning and Review) and Executive 
Order 14094 (Modernizing Regulatory Review)

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

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information-collection burden 
under the PRA. This action does not directly contain any information 
collection, reporting, or record-keeping requirements. The Office of 
Management and Budget (OMB) has previously approved the information 
collection requirements contained in the existing regulations at 40 CFR 
part 131 and has assigned OMB control number 2040-0049.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities.
    The EPA-promulgated WQS are implemented through various water 
quality control programs, including the NPDES program, which limits 
discharges to navigable waters except in compliance with a NPDES 
permit. CWA section 301(b)(1)(C) \21\ and the EPA's implementing 
regulations at 40 CFR 122.44(d)(1) introductory text and (d)(1)(i) 
provide that all NPDES permits shall include any limits on discharges 
that are necessary to meet applicable WQS. Thus, under the CWA, the 
EPA's promulgation of WQS establishes standards that the State 
implements through the NPDES permit process. While the State has 
discretion in developing discharge limits, as needed, to meet the WQS, 
those limits, per the regulation at 40 CFR 122.44(d)(1)(i), ``must 
control all pollutants or pollutant parameters (either conventional, 
nonconventional, or toxic pollutants) which the Director determines are 
or may be discharged at a level that will cause, have the reasonable 
potential to cause, or contribute to an excursion above any [s]tate 
water quality standard, including [s]tate narrative criteria for water 
quality.''
---------------------------------------------------------------------------

    \21\ 301(b), Timetable for achievement of objectives: In order 
to carry out the objective of the chapter there shall be achieved 
not later than July 1, 1977, any more stringent limitation, 
including those necessary to meet water quality standards, treatment 
standards, or schedules of compliance, established pursuant to any 
State law or regulations (under authority preserved by section 1370 
of the title) or any other Federal law or regulation, or required to 
implement any applicable water quality standard established pursuant 
to the chapter.
---------------------------------------------------------------------------

    As a result of this action, the State of California must ensure 
that NPDES permits it issues include any limitations on discharges 
necessary to comply with the WQS established in the final rule. While 
California's implementation of the rule may ultimately result in new or 
revised permit conditions for some dischargers, including small 
entities, the EPA's action, by itself, does not impose any of these 
requirements on small entities; that is, these requirements are not 
self-implementing.

D. Unfunded Mandates Reform Act (UMRA)

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

E. Executive Order 13132 (Federalism)

    This action does not have federalism implications. The EPA 
believes, however, that this action may be of significant interest to 
state governments. Consistent with the EPA's policy to promote 
communications between the EPA and state and local governments, the EPA 
consulted with California early in the process of developing this 
rulemaking to provide the State with an opportunity to provide 
meaningful and timely input.
    On several occasions starting in February 2018, the EPA discussed 
the development of this rule with the California State Water Resources 
Control Board and several Regional Water Quality Control Boards. Early 
in this process, the EPA clarified that if and when the State decides 
to develop and establish its own selenium standards, the EPA would 
assist the State in its process. During these discussions, the EPA also 
explained: the scientific basis for the fish and bird tissue elements 
of the selenium criterion and the methodologies for translating the 
tissue elements to water column values; the external peer review 
process and the comments the EPA received on the derivation of the 
criterion; the EPA's consideration of those comments and responses; 
possible alternatives for criteria or a criterion matrix; the 
assumptions and data being used in the economic analysis associated 
with the rule; and the overall timing of the Federal rulemaking effort. 
The EPA took these discussions with the State into account during the 
drafting of this final rule.

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

    This action does not have Tribal implications as specified in 
Executive Order 13175. This rule does not impose substantial direct 
compliance costs on federally recognized Tribal governments, nor does 
it substantially affect the relationship between the Federal Government 
and Tribes, or the distribution of power and responsibilities between 
the Federal Government and Tribes. Thus, Executive Order 13175 does not 
apply to this action.
    Consistent with the EPA Policy on Consultation and Coordination 
with Indian Tribes, during the development of this action, the EPA 
offered Tribal leaders of potentially affected Tribes in California 
government-to-government consultation on the proposed selenium 
rulemaking. The Torres Martinez Desert Cahuilla Indian Tribe responded, 
with questions and concerns about selenium monitoring in the 
tributaries to the Salton Sea. The tributaries to the Salton Sea have 
State-adopted and EPA-approved site-specific water quality criteria 
(objectives) in place that are not affected by this rule.

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

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per

[[Page 101927]]

the definition of ``covered regulatory action'' in section 2-202 of the 
Executive order. Therefore, this action is not subject to Executive 
Order 13045 because it does not concern an environmental health risk or 
safety risk. This rule relates to protection of aquatic life and 
aquatic-dependent wildlife. Since this action does not concern human 
health, the EPA's Policy on Children's Health also does not apply.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. This action impacts water quality 
standards, which do not regulate the supply, distribution, or use of 
energy.

I. National Technology Transfer and Advancement Act of 1995

    This rule does not involve technical standards.

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

    The EPA believes that the human health and environmental conditions 
that exist prior to this action do not result in disproportionate and 
adverse effects on communities with environmental justice concerns. In 
the EPA's Economic Analysis for the Final Selenium Water Quality 
Criterion for the State of California (economic analysis document), 
which can be found in the docket for this rule, Exhibit 5-2 illustrates 
the geographic distribution of waters where available data indicate 
elevated levels of selenium. These waters are located throughout the 
State. An analysis of proximity to minority and low-income populations 
might or might not reveal patterns of association that differ from 
waters that are not impaired. However, making definitive connections 
between waters monitored for water quality and the effects of selenium 
from the use of these resources would likely depend on many other local 
factors, such as accessibility to and availability of alternative water 
sources.
    The EPA believes that this action is not likely to result in new 
disproportionate and adverse effects on communities with environmental 
justice concerns. The freshwater criterion for selenium in California 
does not address human health impacts, and only applies to aquatic life 
and aquatic-dependent wildlife uses. This rule will support the health 
and abundance of aquatic life and aquatic-dependent wildlife in 
California and will, therefore, not only benefit those species but also 
benefit all communities that rely on or use these ecosystems. The EPA 
finds that, as compared to higher-income populations, low-income 
populations tend to rely more on fishing as a food source,\22\ and 
therefore, this rule may benefit low-income communities. This and other 
EPA actions with goals of protecting fishing resources are a high 
priority for the EPA. The potential benefits associated with this final 
rule are also addressed in the economic analysis document.
---------------------------------------------------------------------------

    \22\ Von Stackelberg, K., et al. (2017). Results of a national 
survey of high-frequency fish consumers in the United States. 
Environmental Research 158, 126-136. https://bgc.seas.harvard.edu/assets/vonstackelberg2017.pdf.
---------------------------------------------------------------------------

    To achieve the benefits associated with a final rule, the EPA 
recognizes that some facilities may need to add pollution control 
measures and incur additional compliance costs over time to meet any 
WQBELs needed to achieve the promulgated selenium criterion. The EPA 
used the California Communities Environmental Health Screening Tool: 
CalEnviroScreen 4.0 tool developed by California Office of 
Environmental Health Hazard Assessment and determined that none of the 
facilities identified in the EPA's Economic Analysis for the Final 
Selenium Water Quality Criterion for the State of California that would 
incur additional annual costs, are located in communities with elevated 
environmental justice concerns. This is one line of evidence that these 
communities would not bear a disproportionate share of the burden with 
promulgation of this rule. To further explore the anticipated impacts, 
the EPA analyzed two facilities identified in the EPA's economic 
analysis that may incur additional compliance costs over time to meet 
any WQBELs needed to achieve the promulgated selenium criterion. For 
illustrative purposes, the EPA first analyzed the Michelson Water 
Reclamation Plant (WRP), which serves an area located in parts of 
Orange County. Using CalEnviroScreen 4.0, the EPA examined education 
level, poverty level, and unemployment level within the service area. 
Some areas showed low environmental justice concerns (high education, 
low poverty, and low unemployment), whereas other areas in the county 
had slightly higher environmental justice concerns (moderate education 
levels, poverty, and unemployment). There did not appear to be a clear 
pattern of disproportionate impacts to specific communities. As 
presented in the economic analysis document, the EPA estimates that 
pollution control upgrades to the Michelson WRP could potentially 
result in a total cost of $4,856,000. The population served by 
Michelson WRP is 331,500 people, which would result in a per-person 
increased cost of $14.65 per year. The average household size in Orange 
County (the area served by Michaelson WRP) is 3.01 \23\ people per 
household, resulting in an estimated additional average household cost 
of $44.09 per year, or $3.67 per month. This potentially modest 
increase in monthly sewerage bill of $3.67 per household per month 
appears unlikely to disproportionally impact low-income populations, 
populations with low education levels, and/or communities with low 
employment rates.
---------------------------------------------------------------------------

    \23\ https://www.census.gov/quickfacts/orangecountycalifornia.
---------------------------------------------------------------------------

    The second facility that the EPA has included in this analysis for 
illustrative purposes may incur annual costs due to implementing 
pollution control upgrades is the Auburn Wastewater Treatment Plant 
(WWTP). The Auburn WWTP serves 13,800 people in the city of Auburn in 
Placer County. Using the CalEnviroScreen 4.0 tool, the EPA examined 
education level, poverty level, and unemployment level within the 
service area. Auburn showed relatively high education levels, moderate 
poverty levels, and moderate unemployment levels. There did not appear 
to be a clear pattern of disproportionate impacts to specific 
communities. As presented in the economic analysis document, the EPA 
estimates that pollution control upgrades to the Auburn WWTP could 
potentially result in a total cost of $491,000. The population served 
by the Auburn WWTP is 13,800 people, which would result in a per-person 
increased cost of $35.58 per year. The average household size in Auburn 
is 2.15 \24\ people per household, resulting in an estimated additional 
average household cost of $76.50 per year, or $6.37 per month. This 
potentially modest increase in monthly sewerage bill of $6.37 per 
household per month appears unlikely to disproportionally impact low-
income populations, populations with low education levels, and/or 
communities with low employment rates.
---------------------------------------------------------------------------

    \24\ https://www.census.gov/quickfacts/auburncitycalifornia.
---------------------------------------------------------------------------

    These examples show that while these communities only have moderate 
environmental justice concerns

[[Page 101928]]

(according to CalEnviroScreen), the low-income portions of these 
communities would not incur a significant burden as a result of this 
final rule. Overall, the EPA anticipates that the abovementioned 
benefits will ultimately outweigh these potential pass-through sewerage 
costs and that this rule will help address any environmental justice 
concerns by benefitting aquatic species and the communities that may 
rely on or use them.
    In addition to Executive Order 12898, and in accordance with Title 
VI of the Civil Rights Act of 1964, each Federal agency shall ensure 
that all programs or activities receiving Federal financial assistance 
that affect human health or the environment do not directly, or through 
contractual or other arrangements, use criteria, methods, or practices 
that discriminate on the basis of race, color, or national origin. With 
that directive in mind, in August 2011 the Environmental Justice 
Interagency Working Group established a Title VI Committee to address 
the intersection of agencies' environmental justice efforts with their 
Title VI enforcement and compliance responsibilities. While the EPA 
only has an oversight role for CWA implementation, if California 
receives Federal funds for CWA implementation, the State is legally 
prohibited from discriminating on the basis of race, color, or national 
origin under Title VI when engaging in CWA implementation activities. 
Additionally, and in compliance with Executive Order 12898, the EPA 
expects that California will consider disproportionately high and 
adverse human health and environmental effects on minority and low-
income populations when implementing this rulemaking under the CWA.
    The information supporting this Executive Order review is contained 
in the EPA's Economic Analysis for the Final Selenium Water Quality 
Criterion for the State of California, the California Communities 
Environmental Health Screening Tool: CalEnviroScreen 4.0 tool developed 
by California Office of Environmental Health Hazard Assessment, and the 
2022 United States census data for Orange County, California and 
Auburn, California.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of Congress and to the Comptroller General of the 
United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 131

    Environmental protection, Incorporation by reference, Indians-
lands, Intergovernmental relations, Reporting and recordkeeping 
requirements, Water pollution control.

Michael S. Regan,
Administrator.

    For the reasons set forth in the preamble, the EPA amends 40 CFR 
part 131 as follows:

PART 131--WATER QUALITY STANDARDS

0
1. The authority citation for part 131 continues to read as follows:

    Authority:  33 U.S.C. 1251 et seq.


0
2. Amend Sec.  131.38 by adding a heading for paragraph (b) and 
revising paragraphs (b)(1) and (c)(3)(ii) and (iii) to read as follows:


Sec.  131.38  Establishment of numeric criteria for priority toxic 
pollutants for the State of California.

* * * * *
    (b) Criteria. (1) Criteria for priority toxic pollutants in the 
State of California as described in table 1 to this paragraph (b)(1):

Table 1 to Paragraph (b)(1)

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[[Page 101929]]

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[GRAPHIC] [TIFF OMITTED] TR17DE24.110


[[Page 101936]]


[GRAPHIC] [TIFF OMITTED] TR17DE24.111

    (i) California Freshwater Selenium Ambient Chronic Water Quality 
Criterion for Protection of Aquatic Life and Aquatic-Dependent 
Wildlife.

Table 2 to Paragraph (b)(1)(i)

[[Page 101937]]

[GRAPHIC] [TIFF OMITTED] TR17DE24.067

BILLING CODE 6560-50-C
    (ii) Priority toxic pollutants. Table 1 to this paragraph (b)(1) 
lists all of the EPA's priority toxic pollutants whether or not 
criteria guidance are available. Blank spaces indicate the absence of 
national criteria guidance under CWA section 304(a). Because of 
variations in chemical nomenclature systems, this listing of toxic 
pollutants does not duplicate the listing in appendix A to 40 CFR part 
423. The EPA has added the Chemical Abstracts Service (CAS) registry 
numbers, which provide a unique identification for each chemical.
    (iii) Criteria recommendations not included in table 1 to this 
paragraph (b)(1). The following chemicals have organoleptic-based 
criteria recommendations that are not included

[[Page 101938]]

in table 1: zinc, 3-methyl-4-chlorophenol.
    (iv) Freshwater and saltwater aquatic life criteria. Freshwater and 
saltwater aquatic life criteria apply as specified in paragraph (c)(3) 
of this section.
* * * * *
    (c) * * *
    (3) * * *
    (ii) For waters in which the salinity is equal to or greater than 
10 parts per thousand 95% or more of the time, the applicable criteria 
are the saltwater criteria in column C, except for selenium in waters 
of the San Francisco Bay upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta where the applicable criteria are the 
freshwater criteria in column B of the National Toxic Rule (``NTR'') at 
Sec.  131.36.
    (iii) For waters in which the salinity is between 1 and 10 parts 
per thousand as defined in paragraphs (c)(3)(i) and (ii) of this 
section, the applicable criteria are the more stringent of the 
freshwater or saltwater criteria, except for selenium in waters of the 
San Francisco Bay upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta where the applicable criteria are the 
freshwater criteria in column B of the NTR. However, the Regional 
Administrator may approve the use of the alternative freshwater or 
saltwater criteria if scientifically defensible information and data 
demonstrate that on a site-specific basis the biology of the water body 
is dominated by freshwater aquatic life and that freshwater criteria 
are more appropriate; or conversely, the biology of the water body is 
dominated by saltwater aquatic life and that saltwater criteria are 
more appropriate. Before approving any change, the EPA will publish for 
public comment a document proposing the change.
* * * * *
[FR Doc. 2024-29483 Filed 12-16-24; 8:45 am]
BILLING CODE 6560-50-P`