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[Federal Register Volume 81, Number 136 (Friday, July 15, 2016)]
[Proposed Rules]
[Pages 46030-46042]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-16266]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

[EPA-HQ-OW-2015-0392; FRL-9946-01-OW]
RIN 2040-AF61

Water Quality Standards; Establishment of Revised Numeric 
Criteria for Selenium for the San Francisco Bay and Delta, State of 
California

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
revise the current federal Clean Water Act selenium water quality 
criteria applicable to the San Francisco Bay and Delta to ensure that 
the criteria are set at levels that protect aquatic life and aquatic-
dependent wildlife, including federally listed threatened and 
endangered species. The San Francisco Bay and Delta ecosystem is at 
risk due to environmental degradation, including impacts from elevated 
levels of selenium, and state and federal actions are underway to 
restore the waterway. Scientific evidence indicates that elevated 
selenium levels can contribute to the decline of fish and aquatic-
dependent birds. EPA promulgated the San Francisco Bay and Delta's 
existing selenium criteria in 1992 as part of the National Toxics Rule, 
using EPA's recommended aquatic life criteria values at the time. 
However, the latest science on selenium fate and bioaccumulation 
indicates that the existing criteria are not protective of aquatic life 
and aquatic-dependent wildlife in the San Francisco Bay and Delta. 
Therefore, EPA is proposing to revise the existing selenium criteria, 
taking into account available science, legal requirements, and EPA 
policies and guidance. EPA's proposal will address the Administrator's 
determination--described in this preamble--that EPA's previously 
promulgated water quality criteria are not adequate to protect the 
designated uses for these waters.

DATES: Comments must be received on or before September 13, 2016.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2015-0392, at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. EPA may publish any comment 
received to its public docket. Do not submit electronically any 
information you consider to be Confidential Business Information (CBI) 
or other information whose disclosure is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e. on the web, cloud, or other file sharing 
system). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
    Two public hearings will be held on Tuesday, August 23, 2016, one 
at 9:00 a.m. and one at 2:00 p.m., at EPA Region 9, 75 Hawthorne 
Street, San Francisco, CA 94105. Additionally, EPA will offer a virtual 
public hearing on the proposed rule via the internet on Monday evening, 
August 22, 2016 from 6:00 p.m. to 8:00 p.m. For details on these public 
hearings, as well as registration information, please visit: https://epa.gov/wqs-tech/water-quality-standards-establishment-revised-numeric-criteria-selenium-san-francisco-bay.

FOR FURTHER INFORMATION CONTACT: Erica Fleisig, Office of Water, 
Standards and Health Protection Division (4305T), U.S. Environmental 
Protection Agency, 1200 Pennsylvania Avenue NW., Washington, DC 20460; 
telephone number: (202) 566-1057; email address: Fleisig.Erica@EPA.gov; 
or Diane E. Fleck, P.E., Esq., Water Division (WTR-2-1), U.S. 
Environmental Protection Agency Region 9, 75 Hawthorne Street, San 
Francisco, CA 94105; telephone number: (415) 972-3527; email address: 
Fleck.Diane@EPA.gov.

SUPPLEMENTARY INFORMATION: This proposed rule is organized as follows:

I. General Information
II. Background
    A. CWA and EPA Regulations
    B. National Toxics Rule
    C. California Toxics Rule
    D. State of California Actions
    E. Applicability of EPA Promulgated Water Quality Standards When 
Final
    F. Selenium Chemistry and Biology
III. Rationale and Approach
    A. Necessity
    B. Administrator's Determination of Necessity
    C. Approach
    D. Proposed Criteria
IV. Implementation and Alternative Regulatory Approaches
V. Endangered Species Act
VI. Economic Analysis
    A. Identifying Affected Entities
    B. Method for Estimating Costs
    C. Results
VII. Statutory and Executive Orders
    A. Executive Order 12866 (Regulatory Planning and Review) and 
Executive Order 13563 (Improving Regulation and 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 Oder 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)

I. General Information

    Applicability: Entities such as industries, stormwater management 
districts, or publicly owned treatment works (POTWs) that directly or 
indirectly discharge selenium to the San Francisco Bay and Delta could 
be indirectly affected by this rulemaking because federal water quality 
standards (WQS) promulgated by EPA would be applicable to Clean Water 
Act (CWA) regulatory programs, such as National Pollutant Discharge 
Elimination System (NPDES) permitting. Citizens concerned with water 
quality in California could also be interested in this rulemaking. 
Categories and entities that could be affected include the following:

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                                      Examples of potentially affected
             Category                             entities
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Industry..........................  Industries discharging pollutants to
                                     the San Francisco Bay and Delta.

[[Page 46031]]

 
Municipalities....................  Publicly owned treatment works or
                                     other facilities discharging
                                     pollutants to the San Francisco Bay
                                     and Delta.
Stormwater Management Districts...  Entities responsible for managing
                                     stormwater runoff in the San
                                     Francisco Bay and Delta.
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    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities that could be indirectly affected 
by this action. Any parties or entities who depend upon or contribute 
to the water quality of the San Francisco Bay and Delta could be 
affected by this proposed rule. To determine whether your facility or 
activities could be affected by this action, you should carefully 
examine this proposed rule. If you have questions regarding the 
applicability of this action to a particular entity, consult the person 
listed in the FOR FURTHER INFORMATION CONTACT section.

II. Background

A. CWA and EPA Regulations

    CWA section 101(a)(2) (33 U.S.C. 1251(a)(2)) establishes a national 
goal, wherever attainable, of ``water quality which provides for the 
protection and propagation of fish, shellfish, and wildlife and 
provides for recreation in and on the water . . .'' In this proposal, 
the relevant goals are the protection and propagation of fish, 
shellfish, and wildlife.
    CWA section 303(c) (33 U.S.C. 1313(c)) directs states to adopt WQS 
for their waters subject to the CWA. CWA section 303(c)(2)(A) and EPA's 
implementing regulations at 40 CFR part 131 require, among other 
things, that a state's WQS specify appropriate designated uses of the 
waters and water quality criteria that protect those uses. EPA's 
regulations at 40 CFR 131.11(a)(1) provide that ``[s]uch criteria must 
be based on sound scientific rationale and must contain sufficient 
parameters or constituents to protect the designated use.'' For waters 
with multiple use designations, the criteria must support the most 
sensitive use (40 CFR 131.11(a)(1)). In addition, 40 CFR 131.10(b) 
provides that ``[i]n designating uses of a water body and the 
appropriate criteria for those uses, the [s]tate shall take into 
consideration the water quality standards of downstream waters and 
shall ensure that its water quality standards provide for the 
attainment and maintenance of the water quality standards of downstream 
waters.''
    States are required to review applicable WQS at least once every 
three years and, if appropriate, revise or adopt new standards (CWA 
section 303(c)(1)). Any new or revised WQS must be submitted to EPA for 
review and approval or disapproval (CWA section 303(c)(2)(A) and 
(c)(3)). Under CWA section 303(c)(4)(B), the Administrator is 
authorized to determine, even in the absence of a state submission, 
that a new or revised standard is needed to meet CWA requirements.
    Under CWA section 304(a), EPA periodically publishes 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 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 EPA has 
published 304(a) criteria, as necessary to support the states' 
designated uses.

B. National Toxics Rule

    On December 22, 1992, EPA promulgated Water Quality Standards; 
Establishment of Numeric Criteria for Priority Toxic Pollutants; 
States' Compliance at 57 FR 60848 (hereafter referred to as the 
National Toxics Rule or NTR).\1\ The NTR established chemical-specific 
numeric criteria for priority toxic pollutants for states that EPA had 
determined were not in compliance with the requirements of CWA section 
303(c)(2)(B). The NTR included selenium water quality criteria for the 
protection of aquatic life in the San Francisco Bay and Delta. On May 
4, 1995, EPA issued a stay of the criteria for metals in the NTR and 
immediately promulgated revised criteria for metals in the NTR in the 
Stay of Federal Water Quality Criteria for Metals at 60 FR 22227 and 
Water Quality Standards; Establishment of Numeric Criteria for Priority 
Toxic Pollutants; States' Compliance--Revision of Metals Criteria, at 
60 FR 22229.\2\ The 1995 Stay and Revision did not change the selenium 
water quality criteria for the San Francisco Bay and Delta. These 
criteria are currently applicable in the Bay and Delta, and consist of 
a chronic criterion of 5 micrograms per liter ([mu]g/L), and an acute 
criterion of 20 [mu]g/L. Both criteria are expressed in the total 
recoverable form of selenium.
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    \1\ The NTR is codified at 40 CFR 131.36.
    \2\ The purpose of the 1995 amendment was, in general, to 
replace aquatic life total recoverable metals criteria with 
dissolved metals criteria to reflect a revised EPA policy that 
dissolved metals criteria better represent the biologically 
available fraction of water borne metals to aquatic organisms. 
Although selenium was included in the analysis for the revised 
policy, the 1995 amendment did not include a freshwater conversion 
factor for selenium, and thus, the aquatic life freshwater selenium 
criteria in the NTR remain in the total recoverable form. The EPA 
policy memorandum, Office of Water Policy and Technical Guidance on 
Interpretation and Implementation of Aquatic Life Metals Criteria, 
by Martha G. Prothro on October 1, 1993, states that selenium is a 
``bioaccumulative chemical and [it is] not appropriate to adjust to 
percent dissolved'' for freshwater selenium criteria (see policy 
memorandum, Attachment 2, page 5).
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    The currently applicable selenium criteria for the protection of 
aquatic life in the San Francisco Bay and Delta were based on EPA's CWA 
section 304(a) recommended criteria values at the time that EPA 
promulgated the criteria in the NTR. These recommendations are 
documented in EPA's Ambient Water Quality Criteria for Selenium--1987, 
Office of Water, EPA-440/5-87-008, September, 1987.
    EPA derived the 1987 freshwater aquatic life recommended criteria 
values for selenium from observed impacts on fish populations at a 
contaminated lake, Belews Lake, in North Carolina. The lake, a cooling 
water reservoir, had been affected by selenium loads from a coal-fired 
power plant. Since aquatic life was exposed to selenium from both the 
water column and diet, the criteria reflect both types of exposure in 
Belews Lake. EPA derived the 1987 saltwater aquatic life recommended 
criteria values for selenium using data from lab studies. EPA 
calculated the criteria in accordance with EPA's Guidelines for 
Deriving Numerical National Water Quality Criteria for the Protection 
of Aquatic Organisms and Their Uses, Office of Research and 
Development, 1985. The 1987 recommended freshwater criteria values for 
total recoverable selenium are 5 [mu]g/L (chronic) and 20 [mu]g/L 
(acute), and the saltwater criteria values for total recoverable 
selenium are 71 [mu]g/L (chronic) and 300 [mu]g/L (acute).
    In the NTR, EPA promulgated selenium criteria for the San Francisco

[[Page 46032]]

Bay and Delta based on the 1987 freshwater recommended criteria values 
for selenium, even though the San Francisco Bay and Delta are marine 
and estuarine waters. EPA used the more stringent freshwater values 
because of a concern that the saltwater criteria were not sufficiently 
protective ``based on substantial evidence that there are high levels 
of selenium bioaccumulation in San Francisco Bay and the saltwater 
criteria fail to account for food chain effects'' and ``utilization of 
the saltwater criteria for selenium in the San Francisco Bay/Delta 
would be inappropriate.'' (57 FR 60898).
    Since then, EPA has taken steps to revise the 1987 CWA 304(a) 
recommended criteria for selenium to better account for bioaccumulation 
through the food chain in different ecosystems. EPA recently published 
a revised CWA 304(a) freshwater recommended criterion for selenium: 
Final Aquatic Life Ambient Water Quality Criterion for Selenium--
Freshwater 2016, US EPA, Office of Water, EPA 822-R-16-006, June, 2016. 
EPA considered the methodology and information used to derive the 
revised CWA 304(a) recommended selenium criterion, along with 
additional information specific to the San Francisco Bay and Delta, in 
developing the revised selenium criteria values for the San Francisco 
Bay and Delta in this proposed rule.

C. California Toxics Rule

    On May 18, 2000, EPA promulgated Water Quality Standards; 
Establishment of Numeric Criteria for Priority Toxic Pollutants for the 
State of California at 65 FR 31681 (hereafter referred to as the 
California Toxics Rule or CTR).\3\ The CTR established numeric water 
quality criteria for priority toxic pollutants for inland surface 
waters and enclosed bays and estuaries within California. EPA 
promulgated the CTR after California rescinded its water quality 
control plans containing pollutant objectives (criteria). The criteria 
that EPA previously promulgated for California in the NTR,\4\ together 
with the criteria promulgated in the CTR and California's designated 
uses and anti-degradation provisions, set water quality standards for 
priority toxic pollutants for inland surface waters and enclosed bays 
and estuaries in California.
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    \3\ The CTR is codified at 40 CFR 131.38.
    \4\ 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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    As required by section 7 of the Endangered Species Act (ESA) (16 
U.S.C. 1531 et seq.), EPA consulted with the U.S. Fish and Wildlife 
Service (FWS) and the U.S. National Marine Fisheries Service (NMFS) 
(collectively, the Services) concerning EPA's rulemaking actions for 
California. EPA initiated consultation in 1994, and in March 2000, the 
Services issued a final Joint Biological Opinion. The final Joint 
Biological Opinion requested that EPA revise its 1987 recommended 
criteria values for selenium to ensure the protection of species listed 
as threatened or endangered, and later update the criteria for 
California consistent with the revised recommendations. In response, 
EPA reserved the acute freshwater selenium criterion from the final May 
2000 CTR.
    In September 2002, EPA, the Services, the U.S. Geological Survey 
(USGS), and the State of California met to discuss the development of 
revised selenium water quality criteria and recommended that 
California-specific selenium water quality criteria be developed as 
wildlife criteria. The agencies agreed that criteria should first be 
developed to protect aquatic life and aquatic-dependent wildlife using 
the Luoma-Presser (USGS) bioaccumulation model \5\ for the San 
Francisco Bay and Delta based on the necessity for more stringent 
criteria in the estuary, and to subsequently develop criteria for the 
rest of California using appropriate methods.
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    \5\ The model developed by Theresa Presser and Sam Luoma is the 
selenium ecosystem bioaccumulation model first presented in 
Forecasting Selenium Discharges to the San Francisco Bay-Delta 
Estuary: Ecological Effects of a Proposed San Luis Drain Extension, 
Open File Report 00-416, Samuel N. Luoma and Theresa S. Presser, 
2000, U.S. Geological Survey, Menlo Park, California. This report 
was revised and superseded in 2006 by Professional Paper 1646, 
Theresa S. Presser and Samuel N. Luoma, U.S. Geological Survey, 
Reston, Virginia. A detailed explanation of the model is contained 
in A Methodology for Ecosystem-Scale Modeling of Selenium, T.S. 
Presser and S.N. Luoma, 2010, Integrated Environmental Assessment 
and Management, Volume 6, Number 4.
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    Starting in 2003, EPA and the Services provided assistance to the 
USGS to model selenium fate and biological uptake in the San Francisco 
Bay and Delta using the USGS bioaccumulation model. USGS completed its 
report, entitled Ecosystem-Scale Selenium Modeling in Support of Fish 
and Wildlife Criteria Development for the San Francisco Bay-Delta 
Estuary, California, Administrative Report (the USGS Report), and 
submitted it to EPA in December 2010. USGS used site-specific data from 
various sources and species-specific data from the FWS. EPA analyzed 
the USGS Report and data from the FWS and other relevant reports to 
develop the selenium criteria for the San Francisco Bay and Delta in 
this proposed rule.
    In 2013, two organizations filed a legal complaint against EPA, 
based in part on the fact that work on updating the reserved acute 
freshwater selenium criterion from the 2000 CTR had not yet been 
completed while EPA had previously determined, in the proposed CTR, 
that the criterion was among those necessary to implement section 
303(c)(2)(B) of the CWA (62 FR 42160, August 5, 1997). EPA ultimately 
consented to a court-ordered resolution of these claims.\6\ Under the 
terms of the court order, EPA committed to developing updated selenium 
criteria for the California waters covered by the original CTR. 
However, this proposed rule relates to a different set of selenium 
criteria: Those selenium criteria that EPA previously proposed and 
finalized for the San Francisco Bay and Delta in the NTR. Since EPA has 
chosen to prioritize the development of this latter set of selenium 
criteria, EPA expects to defer proposing the remaining selenium 
criteria for the rest of California until no later than November 30, 
2018, pursuant to the terms of the court-ordered resolution.
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    \6\ 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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D. State of California Actions

    The State of California has nine Regional Water Quality Control 
Boards (Regional Boards), each located in and overseeing different 
areas of the state. The State Water Resources Control Board (SWRCB) in 
Sacramento oversees the actions of the nine Regional Boards and 
periodically establishes policy and standards for consistency across 
the Regional Boards. The San Francisco Bay Regional Water Quality 
Control Board (SFRWQCB) and the Central Valley Regional Water Quality 
Control Board (CVRWQCB) oversee different parts of the Bay and Delta. 
The SFRWQCB oversees all parts of the San Francisco Bay including the 
South San Francisco Bay, Lower San Francisco Bay, Central San Francisco 
Bay, San Pablo Bay, Carquinez Strait and Suisun Bay, and a small 
portion of the western side of Sacramento-San Joaquin Delta. The 
CVRWQCB oversees the remaining areas of the Delta which include the 
confluences of the Sacramento and the San Joaquin Rivers. Each Regional 
Board has a regional water quality

[[Page 46033]]

control plan (Basin Plan) that sets forth the beneficial (designated) 
uses for the waterbodies it oversees. Once EPA finalizes the proposed 
criteria, each Regional Board will implement the criteria in its WQS 
programs for the waters it oversees.
    In 1978, the SWRCB adopted a comprehensive plan for the Bay and 
Delta estuary: The Water Quality Control Plan for the San Francisco 
Bay/Sacramento-San Joaquin Delta Estuary. The plan was amended in 1991, 
1995 and most recently in December 2006. This plan supplements the two 
regional Basin Plans that cover the estuary and establishes a 
comprehensive set of designated uses for all parts of the Bay and 
Delta. The plan describes the uses as existing uses.
    The site-specific selenium criteria in this proposed rule are 
intended to protect aquatic life and aquatic-dependent wildlife, 
including federally listed threatened and endangered species, in the 
San Francisco Bay and Delta. The designated uses in the SWRCB water 
quality control plan for the protection of aquatic life and aquatic-
dependent wildlife are listed in Table 1. The proposed criteria will 
establish levels of selenium that protect California's designated uses 
for the estuary.

                      Table 1--Existing Designated Uses for the San Francisco Bay and Delta
----------------------------------------------------------------------------------------------------------------
                   Use                            Abbreviation                         Definition
----------------------------------------------------------------------------------------------------------------
Warm Freshwater Habitat.................  WARM                         Uses of water that support warm water
                                                                        ecosystems including, but not limited
                                                                        to, preservation 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 enhancements of
                                                                        aquatic habitats, vegetation, fish, or
                                                                        wildlife, including invertebrates.
Migration of Aquatic Organisms..........  MIGR                         Uses of water that support habitats
                                                                        necessary for the migration or other
                                                                        temporary activities by aquatic
                                                                        organisms, such as anadromous fish.
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 estuarine
                                                                        ecosystems including, but not limited
                                                                        to, preservation and 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 being
                                                                        rare, threatened, or endangered.
----------------------------------------------------------------------------------------------------------------

    The proposed criteria are being set at levels that will protect 
aquatic life and aquatic-dependent wildlife consistent with WARM, COLD, 
EST, WILD and RARE uses, as well as protect aquatic life consistent 
with MIGR and SPWN uses.

E. Applicability of EPA Promgulated Water Quality Standards When Final

    Under the CWA, Congress gave states primary responsibility for 
developing and adopting WQS for their waters (CWA section 303(a)-(c)). 
Although EPA is proposing selenium criteria for the protection of 
aquatic life and aquatic-dependent wildlife for marine and estuarine 
waters in California's San Francisco Bay and Delta, California 
continues to have the option to adopt and submit to EPA protective 
selenium criteria for these waters consistent with CWA section 303(c) 
and EPA's implementing regulations at 40 CFR part 131. EPA encourages 
California to expeditiously adopt protective criteria. Consistent with 
CWA section 303(c)(4), if California adopts and submits selenium 
criteria for the protection of aquatic life and aquatic-dependent 
wildlife, and EPA approves such criteria before finalizing this 
proposed rule, EPA would not proceed with the promulgation for those 
waters for which EPA approves California's criteria.
    If EPA finalizes this proposed rule and California subsequently 
adopts and submits selenium criteria for the protection of aquatic and 
aquatic-dependent wildlife for marine and estuarine waters in the 
estuary, EPA proposes that once EPA approves California's WQS, the EPA-
approved criteria in California's WQS would become the applicable 
criteria for CWA purposes and EPA's promulgated criteria would no 
longer be applicable criteria. EPA would undertake a rulemaking to 
withdraw the federal criteria for selenium, but that process would not 
delay California's approved criteria from becoming the sole applicable 
criteria for CWA purposes. EPA solicits comment on this approach.

F. Selenium Chemistry and Biology

    Selenium is an element that occurs naturally in sediments of marine 
origin and enters the aquatic environment when rainwater comes into 
contact with deposits. Selenium can be further mobilized through 
anthropogenic activities such as agriculture irrigation, mining and 
petroleum refining. Once inorganic selenium is converted into a 
bioavailable form, it enters the food chain and can bioaccumulate. 
Depending on environmental conditions, one or another form of selenium 
such as selenate, selenite and organo-selenium, which differ in 
transformation rates and bioavailability, may predominate in the 
aquatic environment.
    Selenium is an essential micro-nutrient, but the range between 
essential and toxic levels is narrow. A long-standing hypothesis is 
that toxicity occurs through biochemical pathways where excess selenium 
substitutes for sulphur in proteins, which alters their structure and 
function. More recent studies indicate that selenium may affect 
organisms through oxidative stress (see Final Aquatic Life Ambient 
Water Quality Criteria for Selenium--Freshwater 2016, U.S. EPA, Office 
of Water, EPA 822-R-16-006, June, 2016). Elevated selenium levels in 
fish and other wildlife inhibit normal growth and reduce reproductive 
success through effects that lower embryo survival, most notably 
teratogenesis.
    Scientific studies indicate that selenium toxicity to aquatic life 
and aquatic-dependent wildlife is driven by diet (i.e., the consumption 
of selenium-contaminated prey food) rather than by direct exposure in 
the water column. Selenium can accumulate in the aquatic food web 
through various routes and at

[[Page 46034]]

various rates. At the bottom of the food chain, bacteria and algae can 
bioaccumulate selenium to levels that greatly exceed water column 
concentrations, and some invertebrates such as filter-feeding clams, 
can efficiently accumulate selenium from suspended organic and 
inorganic particles. In the San Francisco Bay and Delta, clam-based 
food webs accumulate selenium at a much higher rate than insect-based 
food webs, and the invasive clam species, Potamocorbula amurensis, now 
found throughout the estuary, can accumulate selenium at a much higher 
rate than supplanted clam species. Therefore, species that feed on this 
clam in the estuary, such as diving birds and sturgeon, are exposed to 
higher levels of bioaccumulated selenium than species that feed mainly 
on insects or higher-order species within an insect-based food chain. 
The vulnerability of a species to selenium toxicity is determined by a 
number of factors in addition to the amount of contaminated prey food 
consumed. A species' sensitivity to selenium, its population status, 
and the duration, timing and life stage of exposure are all factors to 
consider. In addition, the hydrologic conditions and water chemistry of 
a water body 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 given the rapid movement and predominant form of 
selenium (selenate). EPA considered these and other factors in 
determining the proposed selenium criteria for the estuary.

III. Rationale and Approach

A. Necessity

    Ecological Health of the Estuary: The San Francisco Bay and Delta 
is the largest estuary on the West Coast of North America and, as part 
of the Pacific Flyway, serves as an important migratory stopover and 
wintering area for a variety of waterfowl. The estuary is formed by the 
intersection of two large river systems, the Sacramento and San Joaquin 
Rivers, which drain approximately 40 percent of California. The estuary 
is comprised of a series of large and small bays, marshes, and channels 
leading to the Pacific Ocean through the Golden Gate. The system is 
critical to California's ecological and economic well-being, and has 
long been the subject of competing interests. The estuary is the hub of 
California's water distribution system, providing drinking water to 25 
million people, supplying irrigation for 4 million acres of farmland, 
and supporting over 750 different species of plants and animals. The 
estuary contributes to the area's economically important recreational 
and commercial fishing and boating industries. However, as a result of 
these competing demands and associated stresses, the ecosystem has 
suffered greatly and water quality in the estuary is impaired, habitat 
is shrinking, important fish populations are at an all-time low, and 
several species are listed as threatened or endangered. In recent 
years, pelagic (open water) species have declined, with some fish 
populations in serious, critical condition. This sudden collapse in 
pelagic species, referred to as the pelagic organism decline (or POD), 
has been intensively studied, but no one factor has been identified as 
the cause. Many factors are thought to be responsible for the decline 
of the estuary's health including water pollution, invasive species, 
water diversion and water project operations, ocean conditions (limited 
food and adverse temperatures), and habitat destruction and 
degradation. For a more detailed discussion, see Unabridged Advanced 
Notice of Proposed Rulemaking for Water Quality Challenges in the San 
Francisco Bay/Sacramento-San Joaquin Delta Estuary, U.S. EPA, February 
2011; 76 FR 9709, February 22, 2011.
    Plan for Restoration: In 2009, the Federal Bay Delta Leadership 
Committee, a Cabinet-level, multi-agency committee charged with 
coordinating federal responses to Bay and Delta issues, issued its 
Interim Federal Action Plan, which outlined the federal government's 
proposal to address water resource management issues in the estuary. 
The Interim Federal Action Plan included an action for EPA to ``address 
the effectiveness of current regulatory mechanisms designed to protect 
water quality in the Delta and its tributaries, including standards for 
toxics, nutrients, and estuarine habitat protection.'' In response, 
after extensive public comment, EPA published Water Quality Challenges 
in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary: EPA's 
Action Plan (the Action Plan) in August 2012. In the Action Plan, EPA 
concluded that existing programs under the CWA were not adequately 
safeguarding resources, and recommended seven priority activities to 
advance the protection and restoration of aquatic resources and ensure 
a reliable water supply in the watershed. The priority activities are: 
1. Strengthen estuarine habitat protection standards; 2. Advance 
regional water quality monitoring and assessment; 3. Accelerate water 
quality restoration through Total Maximum Daily Loads (TMDLs); 4. 
Strengthen selenium water quality criteria; 5. Prevent pesticide 
pollution; 6. Restore aquatic habitats while managing methylmercury; 
and 7. Support the Bay Delta Conservation Plan (now called the 
California WaterFix). This proposed rule is intended to advance 
priority activity number four, Strengthen selenium water quality 
criteria.
    Sources of Selenium: Sources of selenium in the estuary include the 
tributaries flowing into the Delta and Bay, municipal and industrial 
wastewater discharges, stormwater discharges, atmospheric deposition, 
and in-bay sediments. The largest contributors are the Sacramento and 
San Joaquin Rivers and the five oil refineries located along the Bay.
    The headwaters of both rivers originate from snowmelt in the Sierra 
Nevada. The Sacramento River flows north to south into the Delta, and 
drains the northern portion of the Central Valley. The San Joaquin 
River flows east to west, then turns and flows south to north into the 
Delta, and drains the southern and central portions of the Central 
Valley, which are used extensively for farming. The two rivers meet in 
the Delta near Antioch and flow west into the northern reaches of the 
Bay, then southwest to the Pacific Ocean.
    Selenium concentrations in the San Joaquin River are elevated from 
selenium enriched soils on the west side of the Central Valley. 
Agricultural irrigation practices mobilize naturally occurring selenium 
in the heavy soils derived from marine shale and sediment. Selenium 
concentrations in the Sacramento River are much lower than in the San 
Joaquin River and are generally at natural background levels.\7\ Flow 
volumes from each river vary depending on the water year type and 
season, and for the San Joaquin River, the volume of diversions. 
Therefore, selenium loads from the rivers vary, while loads from the 
refineries are more constant.
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    \7\ Water Quality Survey for Selenium in the Sacramento River 
and its Major Tributaries, California Regional Water Quality Control 
Board, Central Valley Region, 1988, Sacramento, California.
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    The San Joaquin watershed is much drier than the Sacramento 
watershed, and flows to the Bay from the San Joaquin River are 
significantly smaller than those from the Sacramento River. In 
addition, dams for hydropower and flood control further limit flows 
from the San Joaquin. Flow volume from the

[[Page 46035]]

San Joaquin into the Delta as measured at Vernalis between 2002 and 
2011 has ranged from approximately 8 to 30 percent of the flow volume 
from the Sacramento River at Freeport during the same time period.\8\ 
At Clifton Court Forebay in the San Joaquin Delta below Vernalis, the 
State Water Project pumps water from the Delta to the California 
Aqueduct for delivery to Southern California, and the Central Valley 
Project pumps water to the Delta Mendota Canal for delivery to Central 
Valley farmers. As a result of these diversions, even less flow from 
the San Joaquin enters the northern part of the Bay.
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    \8\ USGS National Water Information System, Surface-Water Annual 
Statistics for California at: http://waterdata.usgs.gov/ca/nwis/nwis 
(search terms: Surface Water; Annual Flow Data (Stream); Sacramento 
County at Freeport, USGS 11447650, and San Joaquin County at 
Vernalis, USGS 11303500, 2002-2012, compare discharge in cubic feet 
per second based on daily-mean data for water years 2002-2011).
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    Although flows from the San Joaquin are much smaller than flows 
from the Sacramento, selenium concentrations have been significantly 
higher than concentrations in the Sacramento. In 1998 and 1999, 
concentrations of dissolved selenium in the San Joaquin River averaged 
0.71 [micro]g/L, and ranged from 0.40 to 1.07 [micro]g/L at 
Vernalis.\9\ Concentrations in the San Joaquin have declined recently, 
but continue to be higher than levels in the Sacramento River. Recent 
data from 2010-2012 show that dissolved selenium concentrations range 
from 0.207 to 0.47 [micro]g/L in the San Joaquin.\10\ Concentrations in 
the Sacramento have not materially changed during this time period. In 
1998 and 1999, concentrations of dissolved selenium averaged 0.07 
[micro]g/L, and ranged from 0.05 to 0.11 [micro]g/L at Freeport.\9\ 
More recent data from 2010-2012 show levels between 0.062 and 0.09 
[micro]g/L.\10\
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    \9\ Ecosystem-Scale Selenium Modeling in Support of Fish and 
Wildlife Criteria Development for the San Francisco Bay-Delta 
Estuary, California, Theresa S. Presser and Samuel N. Luoma, U.S. 
Geological Survey, 2010, Menlo, Park, California; and using data 
from: (1) Selenium Biogeochemistry in the San Francisco Estuary: 
Changes in Water Column Behavior, G.A. Cutter and L.S. Cutter, 2004, 
Estuarine, Coastal, and Shelf Science, 61:3 pp 463-476; (2) Sources 
and Biogeochemical Cycling of Particulate Selenium in the San 
Francisco Bay Estuary, M.A. Doblin, S.B. Baines, L.S. Cutter, and 
G.A. Cutter, 2006, Estuarine, Coastal, and Shelf Science, 76:4 pp. 
681-694; and (3) Transport, Transformation, and Effects of Selenium 
and Carbon in the Delta of the Sacramento-San Joaquin Rivers: 
Implications for Ecosystem Restoration, L. Lucas and A.R. Stewart, 
2007, CALFED Ecosystem Restoration Program, Agreement No. 
4600001955, Project No. ERP-01-C07.
    \10\ North San Francisco Bay Selenium Characterization Study, 
Final Report (Appendix B Data Tables), Tetra Tech, Inc. on behalf of 
Western States Petroleum Association, 2012, Lafayette, California.
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    Concentrations of dissolved selenium in the Delta and in the 
northern and central portions of the Bay from 1998-1999 ranged from 
0.070 to 0.320 [micro]g/L.\9\ Recent data from 2010-2012 show that 
concentrations have decreased, and range from 0.058 to 0.13 [micro]g/
L.\10\
    Agriculture: Selenium concentrations in the San Joaquin River and 
the estuary are decreasing, in part, as a result of conservation 
actions from the agricultural industry and California's implementation 
of three selenium TMDLs in the Central Valley. TMDLs for a portion of 
the San Joaquin River, the Grassland Marshes, and Salt Slough (a 
tributary) are being implemented through Waste Discharge Requirements 
(WDRs) (permits) and the Grassland Bypass Project to reduce and reroute 
discharges of agricultural return flows from the west side of the 
watershed around sensitive wetlands.
    Between 1986 and 1996, before construction of the Grassland Bypass 
Project and implementation of the TMDLs, selenium loads in the San 
Joaquin at Patterson and Crows Landing below the confluence of the 
Merced River averaged 8,129 pounds per year (lbs/year). Since 2000, 
selenium loads have ranged from 1,526-6,353 lbs/year, with the lowest 
loads in recent years.\11\ Between the mid-1990s and the mid-2000s, 
selenium loading to surface waters decreased by approximately one-half 
to two-thirds through agricultural water conservation measures such as 
harvesting crops that require less water, drip irrigation, water 
recycling and reuse on salt-tolerant crops, and land retirement. 
Although the final WDR loading targets have not been met, the 
agriculture industry has helped reduce selenium loads in the watershed. 
Final targets are scheduled to be achieved by 2019.
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    \11\ Grassland Bypass Project Annual Report 2010-2011, San 
Francisco Estuary Institute for the Grassland Bypass Project 
Oversight Committee, 2013, Chapter 1 (Table 7) by Michael C.S. 
Eacock and Stacy Brown, U.S. Bureau of Reclamation, Fresno, 
California.
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    Refineries: Another source of selenium to the estuary is wastewater 
from the processing of selenium-rich crude oil, from the five major oil 
refineries located along the Bay. The recent decreases in selenium 
concentrations in the Bay are also the result of the refineries 
reducing selenium loads in wastewater discharges in response to 
California's implementation of more stringent NPDES permit limits. 
Selenium levels in crude vary, and the crude from the San Joaquin Basin 
can contain significantly higher levels than other sources of crude. 
Available data indicate that from 1986 through 1992, the cumulative 
selenium load to the Bay from the refineries averaged approximately 
5,000 lbs/year, and ranged from 3,953 to 5,783 lbs/year.\9\ In 1991, 
California required the refineries to reduce their mass discharge of 
selenium and achieve more stringent wastewater concentration limits. 
The refineries achieved their mass-based limits and revised 
concentration limits by 1998. The average cumulative selenium load for 
all refineries since 1999 has been approximately 1,200 lbs/year, down 
approximately 75% from early 1990 levels.\9\ Activities undertaken by 
both the agriculture industry and the refineries have helped to reduce 
selenium loads to the Bay.
    Invasive Clam Species: In the fall of 1986, after major flooding in 
the spring had wiped out large parts of the existing benthic community, 
a small bivalve was discovered in the northern reaches of San Francisco 
Bay.\12\ Its population rapidly increased and spread throughout the 
estuary. The species, Potamocorbula amurensis (P. amurensis), commonly 
known as Corbula, is native to China, Japan, and Korea, and is thought 
to have been introduced to the estuary from ballast water. Adults 
tolerate a wide range of salinity (1 to 32 parts per thousand), and 
although Corbula flourish in subtidal waters, they can also live in 
intertidal mudflats.\12\ The species is remarkably efficient in 
accumulating selenium from its environment \13\ and is responsible for 
the accelerated bioaccumulation of selenium in the food chain of the 
fish and bird species in the Bay and Delta ecosystem. The species most 
at risk in the estuary from the Corbula invasion are believed to be 
clam-eating fish and bird species such as green and white sturgeon, 
scoter and scaup.
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    \12\ The Exotics Guide: Non-native Marine Species of the North 
American Pacific Coast, 2011, Andrew N. Cohen, Center for Research 
on Aquatic Bioinvasions, Richmond, California, and San Francisco 
Estuary Institute, Oakland, California. http://www.exoticsguide.org.
    \13\ Food Web Pathway Determines How Selenium Affects 
Ecosystems: A San Francisco Bay Case Study, 2004, A. Robin Stewart, 
Samuel N. Luoma, Christian E. Schlekat, and Kathryn A. Hieb, 
Environmental Science and Technology, 38:4519-4526.
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    Need for Revised Criteria: EPA now has updated scientific 
information on selenium fate and bioaccumulation, as well as updated 
information on the Bay and Delta estuary ecosystem that was not 
available when EPA developed the existing Bay and Delta selenium 
criteria in the NTR. These data indicate the need for revised criteria. 
The explosion

[[Page 46036]]

of the Corbula population in the early 1990s has drastically changed 
the food web and selenium bioaccumulation dynamics in the Bay and 
Delta. The Ecosystem-Scale Selenium Model for the San Francisco estuary 
allows EPA to develop revised selenium criteria that account for site-
specific and species-specific characteristics, including species with 
greater exposure and/or susceptibility to selenium. In doing so, EPA is 
following the requirements at 40 CFR 131.11(a)(1) to derive criteria 
that are based on a sound scientific rationale and protect the most 
sensitive uses, which in the case of the Bay and Delta include 
migration of aquatic organisms (e.g., anadromous fish species), and 
habitat for rare, threatened and endangered species.
    Although conditions have improved from reduced agriculture and 
refinery loads, ambient levels of selenium are not consistently below 
harmful levels in all parts of the estuary. Revised criteria are 
necessary to help ensure that protective levels are attained in all 
parts of the water body and are maintained in the future to protect 
designated uses. Several indigenous species are listed under the ESA as 
threatened or endangered, including green sturgeon, Chinook salmon, 
steelhead trout, delta smelt and the California Ridgway's rail, and 
many migratory bird species use the estuary as a wintering ground, 
including greater and lesser scaup, and white-winged, surf, and black 
scoter. The analyses to develop the fish tissue and the avian egg 
tissue benchmarks used in the modeling, and the modeling results used 
to derive the proposed water column criteria, indicate the health of 
these species would be negatively impacted from exposure to selenium 
water column concentrations above 0.2 [micro]g/L, which would be 
allowed to occur under the existing NTR selenium criterion of 5.0 
[micro]g/L. Accordingly, EPA finds that it is necessary to propose 
revised and more protective criteria for selenium in order to help 
ensure the continued protection of these vulnerable species and 
associated designated uses.

B. Administrator's Determination of Necessity

    Because California's existing aquatic life criteria for selenium in 
the salt and estuarine waters of the San Francisco Bay, upstream to and 
including Suisun Bay and the Sacramento-San Joaquin Delta, as 
promulgated by EPA in the NTR, are not protective of the applicable 
designated uses per the CWA and EPA's regulations at 40 CFR 131.11, EPA 
determines under CWA section 303(c)(4)(B) that new or revised WQS for 
the protection of aquatic life and aquatic-dependent wildlife are 
necessary to meet the requirements of the CWA for these California 
waters. EPA, therefore, proposes the revised selenium aquatic life and 
aquatic-dependent wildlife criteria in this rule in accordance with 
this 303(c)(4)(B) determination. EPA's determination is not itself a 
final action, nor part of a final action, at this time. After 
consideration of comments on the proposed rule, EPA will take final 
agency action on this rulemaking. It is at that time that any change to 
the water quality standards applicable in California would occur.

C. Approach

    USGS Ecosystem-Scale Selenium Model: The Ecosystem-Scale Selenium 
Model uses species-specific and hydrologic site-specific information to 
model the fate and biological uptake of selenium in an aquatic 
ecosystem through diet. The model was originally developed for the San 
Francisco estuary. It conceptualizes and quantifies several key 
variables in order to predict how selenium moves from the water 
environment to wildlife species through the food chain. It can link 
selenium tissue concentrations in fish or avian wildlife to dissolved 
and particulate selenium concentrations in the water environment and to 
selenium tissue concentrations in prey food.
    Starting in 2003, USGS worked with the Services and EPA to model 
the San Francisco Bay and Delta using various scenarios and endpoints 
(see the USGS Report). Using the best available data for the estuary, 
USGS modeled a clam-based food web from the Golden Gate through Suisun 
Bay to Chipps Island and an insect-based food web from Benicia to Rio 
Vista (in the Sacramento River Delta area) and to Stockton (in the San 
Joaquin River Delta area). Using site-specific partitioning 
coefficients to determine rates of selenium transformation between 
dissolved and particulate phases, the model can predict how efficiently 
selenium enters the base of the food web. Once selenium enters the food 
web, using site-specific trophic transfer factors, which relate 
selenium concentrations in a species to selenium concentrations in its 
food, the model can predict how efficiently selenium moves up into prey 
food and to a predator species. Alternatively, a protective tissue 
level of selenium in an upper trophic level fish species or in a 
terrestrial wildlife species (any predator species) can be used to 
back-calculate and predict the protective concentration of selenium in 
the species' prey, and the protective concentration of dissolved and 
particulate selenium at the base of its food web in the aquatic 
environment.
    EPA Modeling: Using information from the Services on important and/
or vulnerable fish and avian wildlife species in the estuary, and 
building on the USGS modeling of the estuary, EPA modeled the estuary 
to develop site-specific scenarios on which to base the proposed 
criteria (see Technical Support Document for the Proposed Aquatic Life 
and Aquatic-Dependent Wildlife Selenium Water Quality Criteria for the 
San Francisco Bay and Delta (2016), US EPA Region 9, June, 2016).
    EPA considered various protective (benchmark) tissue values for 
representative fish and avian wildlife species to use in the modeling. 
EPA found that the most appropriate tissue benchmark values for fish 
species in the estuary are the recommended values in EPA's recent 
national recommended freshwater aquatic life criterion for selenium 
\14\ and for avian species in the estuary, the egg tissue value 
discussed in EPA's approval of the State of Utah's avian wildlife 
criterion for Gilbert Bay of the Great Salt Lake.\15\ These benchmark 
values represent a 10% Effect Concentration (EC10), which is a 
concentration or level of a pollutant that may adversely affect up to 
10% of a species population. In the national recommended freshwater 
aquatic life criterion for selenium, EPA used EC10 concentrations to 
develop the selenium water quality criterion values.\14\
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    \14\ Final Aquatic Life Ambient Water Quality Criterion for 
Selenium--Freshwater 2016, EPA 822-R-16-006, US EPA, Office of 
Water, 2016, Washington, DC.
    \15\ EPA Action on the Gilbert Bay Selenium Criterion and 
Footnote (14), and Enclosure, US EPA Region 8, 2011, Denver, 
Colorado.
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    EPA modeled two food webs in the estuary, a clam-based web and an 
insect-based web, to determine protective dissolved, particulate and 
prey-tissue selenium values. EPA modeled a clam-based food chain for 
fish and two clam-based food chains for birds that consume Corbula from 
the estuary, each chain representing at-risk fish and bird species in 
the estuary. The clam-based fish modeling represented white and 
juvenile green sturgeon, important species in the estuary that EPA 
determined are the most vulnerable clam-eating fish species. Although 
white sturgeon are not listed under the ESA, green sturgeon are 
threatened and the estuary is designated as critical habitat for the 
species. Since other important vulnerable fish species in the estuary 
such as Sacramento splittail consume less Corbula than sturgeon, the

[[Page 46037]]

other species should be protected if sturgeon are protected.
    EPA modeled two clam-based food web scenarios for at-risk avian 
wildlife to represent two different patterns of avian clam-consumption 
in the estuary. The California Ridgway's rail (formerly the California 
clapper rail) is a small, endangered, indigenous bird that lives year-
round in the estuary and eats mostly mollusks, but only a small 
percentage of Corbula. The five species of migratory diving waterfowl, 
greater and lesser scaup and white-winged, surf, and black scoter, live 
part-time in the estuary, but up to 90% of their diet may consist of 
Corbula from the estuary. These differences in living and eating 
patterns are sufficiently significant that EPA ran the model for each 
separately to ensure the criteria are protective of all avian wildlife 
in the Bay and Delta estuary.
    Lastly, EPA modeled insect-eating fish to represent two important 
anadromous species, the endangered Chinook salmon and the threatened 
steelhead trout, and an important, threatened, indigenous species in 
the estuary, the delta smelt. Since anadromous species use the estuary 
as a migratory corridor, and adults returning to spawn do not feed 
during in-migration, EPA considered the diet of juveniles as they out-
migrate through the estuary to the Pacific Ocean. Delta smelt, and 
juvenile Chinook salmon and steelhead trout, consume mainly insects, 
and do not feed on Corbula.
    The model results indicate that clam-eating fish and clam-eating 
bird species are the most vulnerable species, and require lower 
dissolved and particulate water column selenium concentrations in the 
estuary than insect-eating fish in order to ensure that tissue levels 
stay below concentrations that may cause adverse effects. EPA 
considered the dissolved water column, particulate water column, and 
prey-tissue values necessary to protect all three categories of species 
in setting the proposed regulatory criteria values.

D. Proposed Criteria

    Water quality criteria establish the maximum allowable pollutant 
level that is protective of the designated uses of a water body. States 
(or in this case, EPA) adopt criteria as part of water quality 
standards. Under the CWA, water quality standards are used to derive 
effluent limitations in permits for point source dischargers, thereby 
limiting the amount of pollutants that may be discharged into a water 
body to maintain its designated uses. EPA is proposing selenium water 
quality criteria for the San Francisco Bay and Delta in tissue and in 
the water column (both dissolved and particulate selenium 
concentrations). EPA is proposing selenium tissue concentration 
criteria because they reflect biological uptake through diet, the 
predominant pathway for selenium toxicity, and because they are most 
predictive of the observed biological endpoint of concern: reproductive 
toxicity. However, tissue concentrations present challenges when 
attempting to use them to regulate or limit sources of pollutants. In 
order to facilitate monitoring and regulation of pollutant discharges, 
EPA is also proposing dissolved and particulate water column selenium 
concentration criteria needed to ensure the tissue concentration 
criteria are met. Because EPA used site-specific species and hydrologic 
information in the Ecosystem-Scale Selenium Model to determine the 
protective dissolved and particulate water column and prey selenium 
concentrations associated with the predator tissue concentrations, EPA 
proposes that the criteria in different media are equivalently 
protective and exceedance of any one medium would indicate an 
impairment of the designated use.
    The proposed tissue criteria consist of fish tissue criteria, a 
whole body criterion of 8.5 micrograms per gram ([micro]g/g) dry weight 
(dw) or a muscle criterion of 11.3 [micro]g/g dw, and a clam (or prey) 
tissue criterion of 15 [micro]g/g dw. EPA is proposing each of these 
tissue criteria as an instantaneous measurement not to be exceeded. The 
proposed chronic water column criterion is a dissolved selenium 
criterion of 0.2 [micro]g/L, and the proposed particulate criterion is 
1 [micro]g/g. Each of these two values is a 30-day average, not to be 
exceeded more than once in three years.
    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. These chronic effects are observed at 
much lower concentrations than acute effects. Aquatic and aquatic-
dependent communities are expected to be protected by the chronic 
criteria from any potential acute effects of selenium and an acute 
toxicity criterion is not pertinent for regulatory purposes. However, 
some high, short-term exposures could be detrimental by causing 
significant long-term, residual, bioaccumulative effects, i.e., by the 
introduction of a selenium load into the system. Therefore, EPA is also 
proposing an intermittent exposure water quality criterion to prevent 
long-term detrimental effects from these high, short-term exposures. 
EPA derived the proposed intermittent criterion as a fraction of the 
30-day load based on the chronic water column criterion, after 
accounting for the background selenium concentration. EPA expects that 
a short-term, significantly elevated selenium scenario would rarely 
occur in the San Francisco Bay and Delta due to the large volume of 
water and tidal influences within the estuary that dilute and flush 
selenium loads through the Golden Gate. EPA is proposing this 
intermittent criterion to ensure protection of the ecosystem and for 
consistency with EPA's national recommended aquatic life criterion for 
selenium. A summary of the proposed criteria is included in Table 2.

[[Page 46038]]

[GRAPHIC] [TIFF OMITTED] TP15JY16.097

    The proposed criteria apply to all waters of the San Francisco Bay 
and Delta with salinities of greater than 1 part per thousand (ppt) 95% 
or more of the time.

IV. Implementation and Alternative Regulatory Approaches

    California will have considerable discretion to implement these 
selenium criteria, once finalized, through various water quality 
control programs, including the NPDES program, which limits discharges 
to waters except in compliance with an NPDES permit. Among other 
things, EPA's regulations: (1) Specify how states and authorized tribes 
establish, modify or remove designated uses, (2) specify the 
requirements for establishing criteria to protect designated uses, 
including criteria modified to reflect site-specific conditions, (3) 
authorize states and authorized tribes to adopt WQS variances to 
provide time to achieve the applicable WQS, and (4) allow states and 
authorized tribes to include compliance schedules in NPDES permits to 
provide time for dischargers to achieve effluent limits based on the 
applicable WQS. Designated uses, site-specific criteria, variances, and 
compliance schedules are discussed in more detail below.
    Designated Uses: EPA's proposed selenium criteria apply to marine 
and estuarine waters in the San Francisco Bay and Delta where the 
protection of aquatic life and aquatic-dependent wildlife are 
designated uses (see The Water Quality Control Plan for the San 
Francisco Bay/Sacramento-San Joaquin Delta Estuary, SWRCB, December 13, 
2006). The federal regulations at 40 CFR 131.10 provide 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 water body segment affected by 
this rule and adopts the highest attainable use,\16\ and EPA finds that 
removal to be consistent with CWA section 303(c) and the implementing 
regulations at 40 CFR part 131, then the federal selenium aquatic life 
and aquatic-dependent wildlife criteria would no longer apply to that 
water body segment. Instead, any criteria associated with the newly 
designated highest attainable use would apply to that water body 
segment.
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    \16\ 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 CWA 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 CWA and sub-categories of such 
a use are not attainable (see 40 CFR 131.3(m)).
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    Site-Specific Criteria: The regulations at 40 CFR 131.11 specify 
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 
criteria that would be applied on an area-wide or water body-specific 
basis that meets the regulatory test of protecting the designated uses, 
being scientifically defensible, and ensuring the protection and 
maintenance of downstream WQS. A SSC may be more or less stringent than 
the otherwise applicable federal criteria. A SSC may be appropriate 
when further scientific data and analyses can bring added precision to 
express the concentration of selenium that protects the aquatic life- 
and aquatic-dependent wildlife-related designated uses in a particular 
water body or portion of a water body. Since the San Francisco Bay and 
Delta is a large water body, a different SSC may be appropriate for a 
small segment of the estuary, e.g., South San Francisco Bay, if 
differing flow dynamics indicate that different criteria may be more 
appropriate. As discussed in section II. E., EPA proposes that once EPA 
approves criteria that California adopts and submits after EPA 
finalizes this proposed rule, the site-specific EPA-approved criteria 
in California's WQS would become effective for CWA

[[Page 46039]]

purposes and EPA's promulgated criteria would no longer apply.
    Variances: EPA's regulations at 40 CFR part 131.14 authorize states 
and authorized tribes to adopt WQS variances to provide time to achieve 
the applicable WQS. 40 CFR part 131 defines WQS variances at 131.3(o) 
as time-limited designated uses and supporting criteria for a specific 
pollutant(s) or water quality parameters(s) that reflect the highest 
attainable conditions during the term of the WQS variance. WQS 
variances adopted in accordance with 40 CFR part 131 allow states and 
authorized tribes to address water quality challenges in a transparent 
and predictable way. Variances help states and authorized tribes focus 
on making incremental progress in improving water quality, rather than 
pursuing a downgrade of the underlying water quality goals through a 
designated use change, when the current designated use is difficult to 
attain. EPA is proposing criteria that apply to use designations that 
California has already established. California currently has authority 
to use variances when implementing the criteria, as long as such 
variances are adopted consistent with 40 CFR 131.14 (see Policy for 
Implementation of Toxics Standards for Inland Surface Waters, Enclosed 
Bays, and Estuaries of California, Section 5.3, SWRCB, March 2, 2000, 
amended February 24, 2005; and Procedures for Case-by-Case Exceptions 
from Criteria/Objectives, SWRCB, April 15, 2008). California may use 
EPA-approved variance procedures, with respect to a temporary 
modification of its uses as it pertains to any federal criteria, when 
adopting such variances.
    Compliance Schedules: EPA's regulations at 40 CFR 122.47 and 40 CFR 
131.15 allow states and authorized tribes to include permit compliance 
schedules in their NPDES permits, when appropriate, in order to 
accommodate a discharger's need for additional time to meet its water 
quality-based effluent limits (WQBELs) implementing applicable WQS 
(such as time needed for facility upgrades and operational changes).
    In 1990, EPA concluded that before a permitting authority can 
include a compliance schedule for a WQBEL in an NPDES permit, the state 
or authorized tribe must authorize its use in its WQS or implementing 
regulations.\17\ A permit compliance schedule authorizing provision 
(CSAP) authorizes, but does not require, the permit issuing authority 
to include compliance schedules in permits. EPA's approval of the 
state's or authorized tribe's permit CSAP as a WQS pursuant to 40 CFR 
131.15 ensures that any NPDES permit that contains a compliance 
schedule meets the requirement that the WQBEL and any compliance 
deadlines derive from and comply with applicable WQS.
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    \17\ In the Matter of Star-Kist Caribe, Inc. 3 EAD 172 (April 
16, 1990).
---------------------------------------------------------------------------

    California is authorized to administer the NPDES program in the 
state, and has adopted several mechanisms to authorize compliance 
schedules in NPDES permits. In 2008, California adopted a statewide 
CSAP that EPA subsequently approved under CWA section 303(c), the 
Policy for Compliance Schedules in National Pollutant Discharge 
Elimination System Permits, SWRCB 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 CSAP will allow California to grant compliance 
schedules, as appropriate, based on the federal selenium criteria for 
the Bay and Delta, once these criteria are finalized (see letters dated 
May 20, 2016 and May 27, 2016 from the SWRCB to EPA in the docket for 
this rule).

V. Endangered Species Act

    Pursuant to section 7(a) of the ESA, EPA is consulting with the FWS 
and NMFS concerning EPA's rulemaking action for selenium water quality 
criteria in the San Francisco Bay and Delta. EPA will initiate informal 
consultation, and will transmit to the Services documentation that 
supports the selenium water quality criteria in this proposed rule. As 
a result of this consultation, EPA may modify some provisions of this 
proposed rule. The basis for the selenium criteria in this proposed 
rule stems from many years of ongoing collaboration between EPA and the 
Services. EPA, FWS and NMFS will continue to work closely together on 
this ESA consultation process.

VI. Economic Analysis

    POTWs and industrial point sources that discharge to the Bay and 
Delta may incur some incremental compliance actions and costs as a 
result of the proposed criteria. California has NPDES permitting 
authority for these dischargers, and retains considerable discretion in 
implementing standards. EPA evaluated the potential costs to the 
municipal and industrial NPDES dischargers associated with state 
implementation of EPA's proposed dissolved water column criterion. EPA 
did not evaluate the potential costs associated with state 
implementation of EPA's proposed particulate water column criterion 
because particulate data are not available and because the state has 
discretion concerning implementation. This analysis is documented in 
Economic Analysis for Proposed Aquatic Life and Aquatic-Dependent 
Wildlife Criteria for Selenium in the San Francisco Bay and Delta, 
California (prepared for EPA by Abt Associates in Partnership with PG 
Environmental, LLC, June, 2016), which can be found in the docket for 
this rulemaking.
    NPDES-permitted facilities that discharge selenium to affected 
portions of the Bay and Delta could potentially incur compliance costs. 
The types of affected facilities could include industrial facilities 
and POTWs discharging wastewater to surface waters (i.e., point 
sources). EPA expects that dischargers will use the same types of 
controls as they are currently using to comply with existing selenium 
criteria applicable to the Bay and Delta, to come into compliance with 
the revised criteria. Since the state recently adopted the North San 
Francisco Bay Selenium TMDL, and the TMDL requirements and underlying 
analyses indicate that current ambient water quality conditions 
(dissolved selenium levels at or below 0.2 [micro]g/L) will be 
maintained, EPA did not include costs associated with point sources 
covered in the TMDL analysis.
    EPA did not identify incremental compliance costs for nonpoint 
sources. Unlike point sources, California typically does not require 
nonpoint sources to achieve numeric WQBELs; instead, these sources 
often have best management practice (BMP) requirements, as well as load 
allocations associated with TMDLs. Regional Boards have already 
established TMDLs for selenium in the Lower San Joaquin River and the 
North San Francisco Bay, and EPA assumes the proposed selenium criteria 
will not result in the need for additional controls by nonpoint sources 
in those areas. It is uncertain to what extent nonpoint sources 
contribute selenium loadings to the Lower and South San Francisco Bay. 
EPA assumes that naturally-occurring selenium may be the primary source 
of selenium in the Lower and South San Francisco Bay, and as such, the 
incremental controls and costs for nonpoint sources as a result of the 
proposed criteria will not be significant.

A. Identifying Affected Entities

    Potentially affected facilities include those discharging to waters 
subject to the proposed criteria (i.e., marine or estuarine waters) 
that are not already included in the North San Francisco

[[Page 46040]]

Bay Selenium TMDL. EPA identified 16 such point source facilities, all 
discharging to the Lower and South San Francisco Bay. Of these 
potentially affected facilities, 14 are POTWs and 2 are industrial 
dischargers (the San Francisco International Airport and the Bottling 
Group, LLC). Table 3 summarizes these potentially affected facilities 
by type and category.

                Table 3--Potentially Affected Facilities
------------------------------------------------------------------------
                    Category                       Minor   Major    All
------------------------------------------------------------------------
Municipal.......................................       1      13      14
Industrial......................................       1       1       2
                                                 -----------------------
    Total.......................................       2      14      16
------------------------------------------------------------------------

B. Method for Estimating Costs

    For all potentially affected facilities, EPA used the last five 
years of effluent data (when available) and ambient monitoring data 
from the relevant monitoring station to determine whether there is 
reasonable potential for the facility to cause or contribute to an 
excursion above the proposed dissolved water column criterion for 
selenium. For those facilities that have reasonable potential, EPA 
calculated projected effluent limits. EPA conducted reasonable 
potential analyses and calculated effluent limitations for each 
facility based on California's permitting practices.\18\ In instances 
where the facility's maximum effluent selenium concentration exceeded 
the projected effluent limitations under the proposed criterion, EPA 
determined the likely compliance scenarios and costs. Following 
California's Policy for Implementation of Toxics Standards for Inland 
Surface Waters, Enclosed Bays, and Estuaries of California may result 
in a conservative evaluation for some point sources. However, the 
Regional Boards have substantial discretion to apply other implementing 
permitting procedures that are consistent with the Policy's 
requirements, and may elect to follow different methods to determine 
whether effluent limits are necessary and/or the value of the effluent 
limitations. These alternative methods may result in fewer facilities 
requiring action and/or less stringent permit limitations.
---------------------------------------------------------------------------

    \18\ Pursuant to the Policy for Implementation of Toxics 
Standards for Inland Surface Waters, Enclosed Bays, and Estuaries of 
California, SWRCB, California Environmental Protection Agency, March 
2, 2000, amended February 24, 2005.
---------------------------------------------------------------------------

    EPA assumed that dischargers would pursue the least cost means of 
compliance with WQBELs. Incremental compliance actions attributable to 
the proposed rule may include process optimization, source controls, 
end-of-pipe treatment, and alternative compliance mechanisms (e.g., 
site-specific criteria, variances, and dilution credits). For plants 
discharging at levels above California's minimum quantitation level, 
EPA has assumed that the facility will pursue conventional treatment 
methods to comply with the projected effluent limitations. Facilities 
operating below the quantitation level are discharging near the 
projected limitations, and EPA has assumed that compliance is likely to 
be achievable using process optimization methods. EPA annualized 
capital costs over 20 years using a 3% discount rate to obtain total 
annual costs per facility.

C. Results

    Of the 16 potentially affected facilities that EPA identified, 14 
were found to have reasonable potential to cause or contribute to an 
excursion above the proposed criterion. For compliance with revised 
WQBELs under the proposed rule, EPA estimates the total annual cost to 
be approximately $16 million across the 14 facilities. Of these costs, 
nearly all are attributable to POTW dischargers (i.e., 13 POTWs and one 
industrial facility, the San Francisco International Airport).

VII. Statutory and Executive Orders

A. Executive Order 12866 (Regulatory Planning and Review) and Executive 
Order 13563 (Improving Regulation and Regulatory Review)

    This action is not a significant regulatory action and was, 
therefore, not submitted to the Office of Management and Budget (OMB) 
for review. The proposed rule does not establish any requirements 
directly applicable to regulated entities or other sources of toxic 
pollutants. However, these WQS may serve as a basis for development of 
NPDES permit limits. California has NPDES permitting authority, and 
retains considerable discretion in implementing WQS. In the spirit of 
Executive Order 12866, EPA evaluated the potential costs to NPDES 
dischargers associated with state implementation of EPA's proposed 
criteria. This analysis, Economic Analysis for Proposed Aquatic Life 
and Aquatic-Dependent Wildlife Criteria for Selenium in the San 
Francisco Bay and Delta, California, is summarized in section VI. of 
the preamble and is available in the docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA. While actions to implement these WQS could entail additional 
paperwork burden, this action does not directly contain any information 
collection, reporting, or record-keeping requirements.

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. Small 
entities, such as small businesses or small governmental jurisdictions, 
are not directly regulated by this rule.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. As these water quality criteria are not self-
implementing, 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. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government. This rule 
does not alter California's considerable discretion in implementing 
these WQS, nor would it preclude California from adopting WQS that meet 
the requirements of the CWA, either before or after promulgation of the 
final rule, which would eliminate the need for federal standards upon 
EPA approval of the state WQS. Thus, Executive Order 13132 does not 
apply to this action.
    In the spirit of Executive Order 13132 and consistent with EPA 
policy to promote communications between EPA and state and local 
governments, EPA specifically solicits comments on this proposed action 
from state and local officials.

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 proposed 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

[[Page 46041]]

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, EPA consulted with tribal officials during the 
development of this action. EPA will continue to communicate with the 
tribes prior to its final action.

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 the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because it does not concern an environmental 
health risk or safety risk.

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

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

I. National Technology Transfer and Advancement Act of 1995

    This proposed rulemaking does not involve technical standards.

J. Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations)

    The human health or environmental risk addressed by this action 
will not have potential disproportionately high and adverse human 
health or environmental effects on minority, low-income or indigenous 
populations. The criteria in this proposed rule will support the health 
and abundance of aquatic life and aquatic-dependent wildlife in the San 
Francisco Bay and Delta and will, therefore, benefit all communities 
that rely on these ecosystems.

List of Subjects in 40 CFR Part 131

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

    Dated: June 30, 2016.
Gina McCarthy,
Administrator.
    For the reasons set forth in the preamble, EPA proposes to amend 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.

Subpart D--Federally Promulgated Water Quality Standards

0
2. Section 131.36 is amended by revising paragraph (d)(10)(ii) table 
entry for ``Waters of San Francisco Bay upstream to and including 
Suisun Bay and the Sacramento-San Joaquin Delta'' to read as follows:

Sec.  131.36  Toxics criteria for those states not complying with Clean 
Water Act section 303(c)(2)(B).

* * * * *
    (d) * * *
    (10) * * *
    (ii) * * *

------------------------------------------------------------------------
      Water and use classification             Applicable criteria
------------------------------------------------------------------------
 
                              * * * * * * *
Waters of San Francisco Bay upstream to  These waters are assigned the
 and including Suisun Bay and the         criteria in:
 Sacramento-San Joaquin Delta.           Column B1--pollutants 5a, 10
                                          \a\ and 14
                                         Column B2--pollutants 5a, 10
                                          \a\ and 14
                                         Column D2--pollutants 1, 12,
                                          17, 18, 21, 22, 29, 30, 32,
                                          33, 37, 38, 42-44, 46, 48, 49,
                                          54, 59, 66, 67, 68, 78-82, 85,
                                          89, 90, 91, 93, 95, 96, 98
 
                              * * * * * * *
------------------------------------------------------------------------
\a\ These freshwater selenium criteria are only applicable to the extent
  that the criteria under 40 CFR 131.38(b)(3) are not applicable (i.e.,
  they are only applicable in fresh waters).

* * * * *
0
3. Section 131.38 is amended as follows:
0
a. Revise paragraph (b)(1) table footnotes ``p'' and ``q'';
0
b. Add paragraph (b)(3);
0
c. Revise paragraph (c)(3)(ii);
0
d. Add paragraphs (c)(3)(iv) and (v).

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

* * * * *
    (b)(1) * * *
    Footnotes to Table in Paragraph (b)(1):
* * * * *
    p. The [Reserved] criterion referenced by this footnote does not 
supersede any selenium criterion set out in 40 CFR 131.36 for: Waters 
of the San Francisco Bay, upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta; and waters of Salt Slough, Mud Slough 
(north) and the San Joaquin River, Sack Dam to the mouth of the Merced 
River. The criteria set out in 40 CFR 131.38(b)(3) apply to the salt 
and estuarine waters of the San Francisco Bay, upstream to and 
including Suisun Bay and the Sacramento-San Joaquin Delta, subject to 
40 CFR 131.38(c)(3)(v). The State of California adopted and EPA 
approved a site specific criterion for the San Joaquin River, mouth of 
Merced to Vernalis; therefore, the criterion referenced by this 
footnote does not apply to these waters.
    q. The 5 [micro]g/L criterion referenced by this footnote does not 
supersede any selenium criterion set out in 40 CFR 131.36 for: Waters 
of the San Francisco Bay, upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta; and waters of Salt Slough, Mud Slough 
(north) and the San Joaquin River, Sack Dam to Vernalis. The criteria 
set out in 40 CFR 131.38(b)(3) apply to the salt and estuarine waters 
of the San Francisco Bay, upstream to and including Suisun Bay and the 
Sacramento-San Joaquin Delta, subject to 40 CFR 131.38(c)(3)(v). The 
State of California adopted and EPA approved a site-specific criterion 
for the Grasslands Water District, San Luis National Wildlife Refuge, 
and the Los Banos State Wildlife Refuge; therefore, the criterion 
referenced by this footnote does not apply to these waters.
* * * * *

[[Page 46042]]

    (3) The selenium criteria in Table 1 to this paragraph (b)(3) apply 
to all the waters of San Francisco Bay upstream to and including Suisun 
Bay and the Sacramento-San Joaquin Delta where the salinity is greater 
than 1 part per thousand 95% or more of the time, subject to paragraph 
(c)(3)(v).
[GRAPHIC] [TIFF OMITTED] TP15JY16.098

    (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.
* * * * *
    (iv) Notwithstanding paragraphs (c)(3)(ii) and (iii) of this 
section, for waters of San Francisco Bay upstream to and including 
Suisun Bay and the Sacramento-San Joaquin Delta with salinity greater 
than 1 part per thousand 95% or more of the time, the selenium criteria 
provided in paragraph (b)(3) of this section are the only applicable 
selenium criteria, subject to paragraph (c)(3)(v).
    (v) The criteria in paragraph (b)(3) of this section apply 
concurrently with any water quality criteria adopted by the state, 
except where California adopts site-specific selenium criteria for a 
segment of the estuary that EPA determines meet the requirements of 
Clean Water Act section 303(c) and 40 CFR part 131, in which case 
California's criteria will apply and not the criteria in paragraph 
(b)(3) of this section.

[FR Doc. 2016-16266 Filed 7-14-16; 8:45 am]
 BILLING CODE 6560-50-P
```