[Federal Register Volume 84, Number 84 (Wednesday, May 1, 2019)]
[Proposed Rules]
[Pages 18454-18468]
[FR Doc No: 2019-08464]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

[EPA-HQ-OW-2016-0694; FRL-9967-13-OW]
RIN 2040-AF70

Aquatic Life Criteria for Aluminum in Oregon

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (the EPA) proposes to
establish federal Clean Water Act (CWA) aquatic life criteria for fresh
waters under the State of Oregon's jurisdiction, to protect aquatic
life from the effects of exposure to harmful levels of aluminum. In
2013, the EPA disapproved the State's freshwater acute and chronic
aluminum criteria. The CWA directs the EPA to promptly propose water
quality standards (WQS) that meet CWA requirements if a state does not
adopt WQS addressing the Agency's disapproval. The State has not
adopted and submitted revised freshwater acute and chronic aluminum
criteria to the EPA to address the EPA's 2013 disapproval. Therefore,
in this notice, the EPA proposes federal freshwater acute and chronic
aluminum criteria to protect aquatic life uses in Oregon.

DATES: Comments must be received on or before June 17, 2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2016-0694, at http://www.regulations.gov (our preferred method), or the
other methods identified in this ADDRESSES section. Once submitted,
comments cannot be edited or removed from the docket. The EPA may
publish any comment received to its public docket. Do not submit
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. The EPA will generally not consider comments or comment
contents located outside of the primary submission (i.e., on the web,
cloud, or other file sharing system). 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 https://www.epa.gov/dockets/commenting-epa-dockets.
    The EPA is offering two online public hearings so that interested
parties may provide oral comments on this proposed rule. The first
public hearing will be on Tuesday, June 11, 2019, from 4:00 p.m. to
6:00 p.m. Pacific Time. The second public hearing will be on Wednesday,
June 12, 2019, from 9:00 a.m. to 11:00 a.m. Pacific Time. The EPA plans
to make a transcript of the public hearings available to the public in
the rulemaking docket. The EPA will respond to substantive comments
received as part of developing the final rule and will include comment
responses in the

rulemaking docket. For more details on the public hearings and a link
to register, please visit http://www.epa.gov/wqs-tech/water-quality-standards-regulations-oregon.

FOR FURTHER INFORMATION CONTACT: Heather Goss, Office of Water,
Standards and Health Protection Division (4305T), Environmental
Protection Agency, 1200 Pennsylvania Avenue NW, Washington, DC 20460;
telephone number:<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: This proposed rule is organized as follows:

I. General Information
    Does this action apply to me?
II. Background
    A. Statutory and Regulatory Authority
    B. The EPA's Disapproval of Oregon's Freshwater Aluminum
Criteria
    C. General Recommended Approach for Deriving Aquatic Life
Criteria
III. Freshwater Aluminum Aquatic Life Criteria
    A. The EPA's CWA Section 304(a) National Recommended Freshwater
Aluminum Criteria
    B. Proposed Acute and Chronic Aluminum Criteria for Oregon's
Fresh Waters
    C. Implementation of Proposed Freshwater Acute and Chronic
Aluminum Criteria in Oregon
    D. Incorporation by Reference
IV. Critical Low Flows and Mixing Zones
V. Endangered Species Act
VI. Under what conditions will federal standards not be promulgated
or be withdrawn?
VII. Alternative Regulatory Approaches and Implementation Mechanisms
    A. Designating Uses
    B. WQS Variances
    C. NPDES Permit Compliance Schedules
VIII. Economic Analysis
    A. Identifying Affected Entities
    B. Method for Estimating Costs
    C. Results
IX. Statutory and Executive Order Reviews
    A. Executive Order 12866 (Regulatory Planning and Review) and
Executive Order 13563 (Improving Regulation and Regulatory Review)
    B. Executive Order 13771 (Reducing Regulations and Controlling
Regulatory Costs)
    C. Paperwork Reduction Act
    D. Regulatory Flexibility Act
    E. Unfunded Mandates Reform Act
    F. Executive Order 13132 (Federalism)
    G. Executive Order 13175 (Consultation and Coordination With
Indian Tribal Governments)
    H. Executive Order 13045 (Protection of Children From
Environmental Health and Safety Risks)
    I. Executive Order 13211 (Actions That Significantly Affect
Energy Supply, Distribution, or Use)
    J. National Technology Transfer and Advancement Act of 1995
    K. Executive Order 12898 (Federal Actions To Address
Environmental Justice in Minority Populations and Low-Income
Populations)

I. General Information

Does this action apply to me?

    Aluminum naturally occurs in surface waters, but under certain
environmental conditions, it can be converted to toxic forms that can
be toxic to aquatic life. Anthropogenic activities such as bauxite
mining, alumina refining, production of aluminum products, and
manufacturing processes can contribute aluminum to surface waters.\1\
In addition, alum (potassium aluminum sulfate), used in clarification
processes in drinking water and wastewater processes, can contribute to
levels of aluminum in surface waters. Lastly, certain activities, such
as wastewater discharges, stormwater runoff, mining, or agriculture can
influence a waterbody's pH, dissolved organic carbon (DOC), or total
hardness and, therefore, the toxicity of aluminum in that waterbody.
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    \1\ Agency for Toxic Substances and Disease Registry (ATSDR)
Toxicological Profile for Aluminum, 2008 (https://www.atsdr.cdc.gov/toxprofiles/tp22.pdf).
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    Entities such as industrial facilities, stormwater management
districts, or publicly owned treatment works (POTWs) that discharge
pollutants to fresh waters of the United States under the State of
Oregon's jurisdiction could be indirectly affected by this rulemaking,
because federal WQS promulgated by the EPA would be applicable WQS for
the State for CWA purposes. These WQS are the minimum standards which
must be used in CWA regulatory programs, such as National Pollutant
Discharge Elimination System (NPDES) permitting \2\ and identifying
impaired waters under CWA section 303(d). Citizens concerned with water
quality in Oregon could also be interested in this rulemaking.
Categories and entities that could potentially be affected include the
following:
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    \2\ Before any water quality based effluent limit is included in
an NPDES permit, the permitting authority (here, the State of
Oregon), will first determine whether a discharge ``will cause or
has the reasonable potential to cause, or contribute to an excursion
above any WQS.'' 40 CFR 122.44 (d)(1)(i) and (ii).

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                                      Examples of potentially affected
             Category                             entities
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Industry..........................  Industries discharging pollutants to
                                     fresh waters of the United States
                                     in Oregon.
Municipalities....................  Publicly owned treatment works or
                                     other facilities discharging
                                     pollutants to fresh waters of the
                                     United States in Oregon.
Stormwater Management Districts...  Entities responsible for managing
                                     stormwater runoff in the State of
                                     Oregon.
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    This table is not intended to be exhaustive, but rather provides a
guide for readers to identify entities that could potentially be
affected by this action. Any parties or entities who depend upon or
contribute to the water quality of Oregon's waters 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. Statutory and Regulatory Authority

    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) \3\
provides that WQS shall consist of designated uses of the waters and
water quality criteria based on those uses. The 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 [and] [f]or waters with
multiple use designations, the criteria shall support the most
sensitive use.'' 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.''
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    \3\ CWA section 303(c)(2)(A): Whenever the State revises or
adopts a new standard, such revised or new standard shall be
submitted to the Administrator. Such revised or new water quality
standard shall consist of the designated uses of the navigable
waters involved and the water quality criteria for such waters based
upon such uses. Such standards shall be such as to protect the
public health or welfare, enhance the quality of water and serve the
purposes of this chapter. Such standards shall be established taking
into consideration their use and value for public water supplies,
propagation of fish and wildlife, recreational purposes, and
agricultural, industrial, and other purposes, and also taking into
consideration their use and value for navigation.
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    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) \4\ 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) \5\ and 40 CFR 131.20 and 131.21). If
the EPA disapproves a state's new or revised WQS, the CWA provides the
state 90 days to adopt a revised WQS that meets CWA requirements, and
if it fails to do so, the Agency shall promptly propose and then within
90 days promulgate such WQS unless the Agency approves a state
replacement WQS first (CWA section 303(c)(3) and (c)(4) \6\).
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    \4\ CWA section 303(c)(1): The Governor of a State or the state
water pollution control agency of such State shall from time to time
(but at least once each three year period beginning with October 18,
1972) hold public hearings for the purpose of reviewing applicable
water quality standards and, as appropriate, modifying and adopting
standards. Results of such review shall be made available to the
Administrator.
    \5\ CWA section 303(c)(3): If the Administrator, within sixty
days after the date of submission of the revised or new standard,
determines that such standard meets the requirements of this
chapter, such standard shall thereafter be the water quality
standard for the applicable waters of that State. If the
Administrator determines that any such revised or new standard is
not consistent with the applicable requirements of this chapter, he
shall not later than the ninetieth day after the date of submission
of such standard notify the State and specify the changes to meet
such requirements. If such changes are not adopted by the State
within ninety days after the date of notification, the Administrator
shall promulgate such standard pursuant to paragraph (4) of this
subsection.
    \6\ CWA section 303(c)(4): The Administrator shall promptly
prepare and publish proposed regulations setting forth a revised or
new water quality standard for the navigable waters involved--(A) if
a revised or new water quality standard submitted by such State
under paragraph (3) of this subsection for such waters is determined
by the Administrator not to be consistent with the applicable
requirements of this Act . . . The Administrator shall promulgate
any revised or new standard . . . not later than ninety days after
he publishes such proposed standards, unless prior to such
promulgation, such State has adopted a revised or new water quality
standard which the Administrator determines to be in accordance with
this chapter.''
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    Under CWA section 304(a), the 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. Where the EPA has published recommended criteria, states should
establish numeric water quality criteria based on the Agency's CWA
section 304(a) recommended criteria, CWA section 304(a) recommended
criteria modified to reflect site-specific conditions, or other
scientifically defensible methods (40 CFR 131.11(b)(1)). In all cases
criteria must be sufficient to protect the designated use and be based
on sound scientific rationale (40 CFR 131.11(a)(1)).

B. The EPA's Disapproval of Oregon's Freshwater Aluminum Criteria

    On July 8, 2004, Oregon submitted 89 revised aquatic life criteria
for 25 pollutants to the EPA for review under CWA section 303(c)
including acute and chronic criteria for aluminum. Many of Oregon's
revised criteria were the same as the EPA's national recommended CWA
section 304(a) aquatic life criteria at the time. Oregon subsequently
submitted revised WQS to the EPA for CWA section 303(c) review on April
23, 2007. The EPA did not take CWA section 303(c) action to approve or
disapprove within the statutorily mandated timeline (CWA 303(c)(3)). On
May 29, 2008, the U.S. District Court for the District of Oregon
entered a consent decree setting deadlines for the EPA to take action
under section 303(c) of the CWA on Oregon's July 8, 2004, submission of
aquatic life criteria (Northwest Environmental Advocates v. U.S. EPA,
No. 06-479-HA (D. Or. 2006)). On November 27, 2012, the District Court
issued an extension of the applicable deadlines for the EPA's CWA
section 303(c) action and amended the decree to require the Agency to
act by January 31, 2013, on Oregon's July 8, 2004, submission of
aquatic life criteria, as amended by subsequent submissions by Oregon
dated April 23, 2007, and July 21, 2011.
    The EPA initially considered approving Oregon's aluminum criteria.
Prior to taking a final action on the aquatic life criteria, however,
the EPA requested formal consultation with the National Marine
Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS)
on its proposed approval of the State's criteria, consistent with
section 7(a)(2) of the Endangered Species Act (ESA). The EPA initiated
this consultation on January 14, 2008, by submitting a biological
evaluation to NMFS and USFWS, which contained an analysis of the
potential effects of the Agency's proposed approval of Oregon's
criteria, including criteria for aluminum, on threatened and endangered
species in Oregon.
    Before receiving a biological opinion from NMFS or USFWS, the EPA
realized that the Agency's initial understanding that Oregon's criteria
were entirely equivalent to the Agency's 1988 CWA section 304(a)
recommended criteria was incorrect. While the EPA's 1988 CWA section
304(a) recommended aluminum criteria ``apply at pH values of 6.5-9.0,''
the Agency later identified a footnote to Oregon's revised aluminum
criteria table specifying that Oregon's aluminum criteria applied ``to
waters with pH values less than 6.6 and hardness values less than 12
mg/L (as CaCO3).'' The State had not supplied a scientific
rationale to justify the application of the criteria to pH values less
than 6.6 and hardness values less than 12 mg/L. As a result, the EPA
prepared to disapprove the aluminum criteria. The EPA sent a letter to
NMFS and USFWS identifying this change. USFWS had already completed and
transmitted its biological opinion to the EPA by that point and the
Agency was therefore unable to withdraw the consultation request for
aluminum. USFWS biological opinion (provided to the EPA on July 31,
2012) found that the Agency's proposed approval of Oregon's aquatic
life criteria (which at the time of the consultation, was based on the
application of the aluminum criteria to waters with pH 6.5-9.0) would
not jeopardize the continued existence of listed species or result in
the destruction or adverse modification of designated critical habitat
under USFWS jurisdiction.
    NMFS had not yet transmitted its analysis to the EPA at that time,
so the Agency sent a letter to NMFS withdrawing its request for
consultation on Oregon's acute and chronic aluminum criteria. NMFS
acknowledged the EPA's request to withdraw the aluminum criteria from
consultation in the biological opinion; however, NMFS did not modify
the document to exclude the acute and chronic aluminum criteria. On
August 14, 2012, NMFS concluded in its biological opinion that seven of
Oregon's revised freshwater criteria would jeopardize the continued
existence of endangered species in Oregon for which NMFS was
responsible, including acute and chronic aluminum (applied to waters
with pH 6.5-9.0).\7\ NMFS acknowledged the EPA's request to withdraw
the aluminum criteria from consultation and indicated that it would
await a further request from the EPA regarding

the EPA's future actions on Oregon's aluminum criteria.
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    \7\ In addition to acute and chronic aluminum, the other
criteria were the freshwater criteria Oregon adopted to protect
aquatic life from adverse acute and chronic effects from ammonia and
copper, as well as the criterion to prevent adverse acute effects
from cadmium.
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    On January 31, 2013, the EPA disapproved several of the State's
revised aquatic life criteria under CWA section 303(c). The EPA
disapproved the State's aluminum criteria because the State had not
supplied a scientific rationale for the conditions under which the
criteria would apply. On April 20, 2015, the EPA was sued for failing
to promptly prepare and publish replacement criteria for seven of the
aquatic life criteria disapproved in its January 31, 2013 action
(Northwest Environmental Advocates v. U.S. EPA, 3:15-cv-00663-BR (D.
Or. 2015)). This lawsuit was resolved in a consent decree entered by
the District Court on June 9, 2016 which established deadlines for the
EPA to address the disapproved aquatic life criteria by either
approving replacement criteria submitted by Oregon or by proposing and
promulgating federal criteria. The State and the EPA have addressed the
disapprovals for five of the criteria subject to the consent decree,\8\
but the State has not yet addressed the EPA's 2013 disapproval of its
freshwater criteria for acute and chronic aluminum (the sixth and
seventh of the disapproved criteria). For the freshwater aluminum
criteria, the consent decree originally established deadlines for the
EPA to propose federal criteria by December 15, 2017, and to take final
action on the proposal by September 28, 2018. On December 5, 2017, the
District Court granted an extension of the applicable deadlines for the
EPA's proposal and final action. At that time, the consent decree
required the EPA to propose federal criteria for the State by March 15,
2018, and to take final action on the proposal by March 27, 2019. On
March 1, 2018, the District Court again granted an extension of the
consent decree deadlines for the EPA's proposed and final actions. The
consent decree required that by March 15, 2019, the EPA will either
approve aluminum criteria submitted by Oregon or the EPA will sign a
notice of federal rulemaking proposing aluminum criteria for Oregon.
The consent decree includes a force majeure clause relating to
``circumstances outside the reasonable control of EPA [that] could
delay compliance with the deadlines specified in this Consent Decree.
Such circumstances include . . . a government shutdown.'' Due to the
35-day government shutdown that occurred between December 22, 2018, and
January 25, 2019, the deadline for signing a rule proposal is April 19,
2019. As a result, the EPA is proposing freshwater acute and chronic
criteria for aluminum in Oregon in this rule in accordance with CWA
section 303(c)(3) and (c)(4) requirements, and consistent with the
schedule established in the consent decree. The consent decree also
requires that by March 27, 2020, the EPA will either approve aluminum
criteria submitted by Oregon or sign a notice of final rulemaking.
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    \8\ For more information on how the State and the EPA proceeded
with regard to the other parameters, the proposed rule for copper
and cadmium and final rule for cadmium are included in the docket
for this rule.
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C. General Recommended Approach for Deriving Aquatic Life Criteria

    The proposed aluminum criteria for Oregon are based on the EPA's
2018 final CWA section 304(a) national recommended freshwater aquatic
life criteria for aluminum (Final Aquatic Life Ambient Water Quality
Criteria for Aluminum 2018, EPA 822-R-18-001, as cited in 83 FR 65663),
which were developed consistent with the EPA's Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection of Aquatic
Organisms and Their Uses (referred to as the ``Aquatic Life
Guidelines'').\9\ These criteria apply to fresh waters and account for
water chemistry characteristics that affect aluminum bioavailability
and toxicity. The final 2018 CWA section 304(a) national recommended
freshwater aquatic life criteria for aluminum replaced the previous CWA
section 304(a) national recommended freshwater aquatic life criteria
for aluminum which were issued in 1988.\10\ While the earlier criteria
were in place at the time that EPA disapproved the State's aluminum
criteria, the EPA has since updated its CWA 304(a) national recommended
criteria and is proposing criteria for Oregon consistent with the new
recommendations.
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    \9\ USEPA. 1985. Guidelines for Deriving Numerical National
Water Quality Criteria for the Protection of Aquatic Organisms and
Their Uses. U.S. Environmental Protection Agency, Office of Research
and Development, Duluth, MN, Narragansett, RI, Corvallis, OR. PB85-
227049. https://www.epa.gov/sites/production/files/2016-02/documents/guidelines-water-quality-criteria.pdf.
    \10\ Ambient Water Quality Criteria for Aluminum--1988, EPA 440/
5-86-008, August 1988, https://nepis.epa.gov/Exe/ZyPDF.cgi/2000M5FC.PDF?Dockey=2000M5FC.PDF.
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    Under the Agency's CWA section 304(a) authority, the EPA develops
recommended criteria and methodologies to protect aquatic life and
human health for specific pollutants and pollutant parameters. These
recommended criteria and methodologies are subject to public comment as
well as scientific expert review before the EPA releases them as formal
Agency recommendations for states to consider when developing and
adopting water quality criteria. The EPA derives criteria for the
protection of aquatic life consistent with its Aquatic Life Guidelines.
The EPA's Aquatic Life Guidelines describe an objective way to estimate
the highest concentration of a substance in water that will not present
a significant risk to the aquatic organisms in the water. If a CWA
section 304(a) recommendation exists, states may use it as a basis for
their WQS or, alternatively, can use a modified version that reflects
site-specific conditions, or another scientifically defensible method.
40 CFR 131.11(b).
    Numeric criteria derived consistent with the EPA's Aquatic Life
Guidelines are expressed as short-term (acute) and long-term (chronic)
values. The combination of a criterion maximum concentration (CMC), a
one-hour average value, and a criterion continuous concentration (CCC),
typically specified as a four-day average value, protects aquatic life
from acute and chronic toxicity, respectively. Neither value is to be
exceeded more than once in three years. The EPA selected the CMC's one-
hour averaging period because high concentrations of certain pollutants
can cause death in one to three hours, and selected the CCC's four-day
averaging period to prevent increased adverse effects on sensitive life
stages. The EPA based its maximum exceedance frequency recommendation
of once every three years on the ability of aquatic ecosystems to
recover from the exceedances. An exceedance occurs when the average
concentration over the duration of the averaging period is above the
CCC or the CMC.
    The Aquatic Life Guidelines recommend having toxicity test data
from a minimum of eight taxa of aquatic organisms to derive criteria.
These taxa are intended to be representative of a wide spectrum of
aquatic life, and act as surrogates for untested species. Therefore,
the specific test organisms do not need to be present in the water(s)
where the criteria will apply. However, a state may develop site-
specific criteria using species residing at a local site. In developing
site-specific criteria, the EPA recommends that the state maintain
similar broad taxonomic representation in calculating the site-specific
criteria to ensure protection of the most sensitive species at the site
and so the state can demonstrate that the species included in the
derivation of the EPA's national criteria recommendation

is not present/does not serve as a surrogate for other species at the
site.

III. Freshwater Aluminum Aquatic Life Criteria

A. The EPA's CWA Section 304(a) National Recommended Freshwater
Aluminum Criteria

    In December 2018, the EPA published in the Federal Register (83 FR
65663) CWA section 304(a) national recommended freshwater aquatic life
criteria for aluminum (referred to in this notice as ``final 2018
recommended national criteria''). The published final 2018 recommended
national criteria represent the latest scientific knowledge and
understanding of the interaction between water chemistry and aluminum
toxicity and is a scientifically defensible method upon which the EPA
is basing this CWA action.\11\ The final 2018 recommended national
criteria are based upon Multiple Linear Regression (MLR) models for
fish and invertebrate species that use pH, DOC, and total hardness to
quantify the effects of these water chemistry parameters on the
bioavailability and resultant toxicity of aluminum to aquatic
organisms. The MLR models are then used to normalize the available
toxicity data to accurately reflect the effects of the water chemistry
(pH, DOC, total hardness) on the toxicity of aluminum to tested
species. These normalized toxicity test data are then used in a
criteria calculator to generate criteria for specific water chemistry
conditions, the water-chemistry-condition-specific CMC and CCC outputs.
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    \11\ Aquatic Life Ambient Water Quality Criteria for Aluminum,
EPA 822-R-18-001, December 2018, https://www.epa.gov/wqc/2018-final-aquatic-life-criteria-aluminum-freshwater.
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    The final 2018 recommended national aluminum criteria are expressed
as total recoverable metal concentrations. The EPA notes that while the
criteria values for metals are typically expressed as dissolved metal
concentrations, the current EPA-approved CWA Test Methods \12\ for
aluminum in natural waters and waste waters measure total recoverable
aluminum. The use of total recoverable aluminum may be considered
conservative because it includes monomeric (both organic and inorganic)
forms, polymeric and colloidal forms, as well as particulate forms and
aluminum sorbed to clays. However, toxicity data comparing toxicity of
aluminum using total recoverable aluminum and dissolved aluminum
demonstrated that toxic effects increased with increasing
concentrations of total recoverable aluminum even though the
concentration of dissolved aluminum was relatively constant. If
aluminum criteria were based on dissolved concentrations, toxicity
would likely be underestimated, as colloidal forms and hydroxide
precipitates of the metal that can dissolve under natural conditions
and become biologically available would not be measured. The criteria
document contains more discussion of the studies that informed the
choice to use total recoverable aluminum as the basis for the final
2018 recommended national criteria.
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    \12\ 40 CFR part 136.3 and Appendix C.
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    The numeric outputs of the final 2018 recommended national criteria
models for a given set of conditions will depend on the specific pH,
DOC, and total hardness entered into the models. The model outputs (CMC
and CCC) for a given set of input conditions are numeric values that
would be protective for that set of input conditions. Users of the
models can determine outputs in two ways: (1) Use the look-up tables
provided in the criteria document to find the numeric aluminum CMC and
CCC most closely corresponding to the local conditions for pH, DOC, and
total hardness or (2) use the provided Aluminum Criteria Calculator
V.2.0 to enter the pH, DOC, and total hardness conditions at a specific
site to calculate the numeric aluminum CMC and CCC corresponding to the
local input conditions.
    As with all scientific analyses, there are potential uncertainties
in the aluminum criteria approaches to quantifying the toxic effects of
aluminum to aquatic life in the environment, particularly when the
input parameters fall outside the bounds of the toxicity data
underlying the MLR model that supports the criteria calculator. Section
5 of the EPA's final 2018 recommended national criteria document
contains more detailed information regarding these uncertainties and
the ways the EPA has addressed these uncertainties in developing the
criteria document and calculator to ensure the criteria values are
protective of applicable aquatic life designated uses. In the case of
Oregon waters, an estimated 99% of the State's waters fall within the
bounds of the model, and criteria values generated by the calculator
are expected be protective of applicable aquatic life designated
uses.\13\ In situations where water chemistry for a particular water
falls outside the bounds of the model and the results are more
uncertain, the State should use its discretion and risk management
judgment to determine if additional toxicity data should be generated
to further validate toxicity predictions or if it should develop new or
modified models for site specific criteria for such locations.
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    \13\ ``Analysis of the Protectiveness of Default Ecoregional
Aluminum Criteria Values,'' which can be found in the docket.
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    In order to calculate numeric water quality criteria that will
protect the aquatic life designated uses of a site over the full range
of ambient conditions and toxicity, multiple model outputs will need to
be reconciled. The following section describes options for reconciling
model outputs.

B. Proposed Acute and Chronic Aluminum Criteria for Oregon's Fresh
Waters

    To protect aquatic life in Oregon's fresh waters, the EPA proposes
aluminum criteria for Oregon that incorporate by reference the
calculation of CMC and CCC freshwater aluminum criteria values for a
site using the final 2018 recommended national criteria. That means
that the proposed CMC and CCC freshwater aluminum criteria values for a
site shall be calculated using the 2018 Aluminum Criteria Calculator
V.2.0 (Aluminum Criteria Calculator V.2.0.xlsx) or a calculator in R
\14\ or other software package using the same 1985 Guidelines
calculation approach and underlying model equations as in the Aluminum
Criteria Calculator V.2.0.xlsx as established in the final 2018
recommended national criteria. Consistent with the final 2018
recommended national criteria, the EPA proposes to express the CMC as a
one-hour average total recoverable aluminum concentration (in [micro]g/
L) and the CCC as a four-day average total recoverable aluminum
concentration (in [micro]g/L), and that the CMC and CCC are not to be
exceeded more than once every three years.
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    \14\ R is a free software environment for statistical computing
that compiles and runs on a wide variety of UNIX platforms, Windows
and MacOS. (https://www.r-project.org/).
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    The EPA concludes that its final 2018 recommended national criteria
represent the latest scientific knowledge on aluminum speciation,
bioavailability, and toxicity, and provides predictable and repeatable
outcomes. Consistent with the Aquatic Life Guidelines, the final 2018
recommended national criteria protect aquatic life for acute effects
(mortality and immobility) as well as chronic effects (growth,
reproduction, and survival) at a level of 20% chronic Effects
Concentration (EC20) for the 95th percentile of sensitive genera. The
final 2018 recommended national criteria are

based on a range of toxicological data including data on Oregon
threatened and endangered species or their closest taxonomic
surrogates. The models on which the criteria are based are therefore
appropriate for deriving CMC and CCC values that will protect aquatic
life in Oregon. The EPA recommends that commenters consult the docket
for the final 2018 recommended national criteria document for
information on the science underlying that recommendation [Docket: EPA-
HQ-OW-2017-0260].
    The EPA requests comment on the proposal to promulgate aluminum
criteria for freshwaters in Oregon based on the final 2018 recommended
national criteria. The EPA also requests comment on any alternative
scientifically defensible criteria calculation methods or models that
differ from the final 2018 recommended national criteria. The EPA may
consider modifications to the criteria the EPA is proposing for Oregon
if warranted based on, among other things, public input, tribal
consultation, new data, or evaluations of listed species completed
during ESA consultation, or the results of ESA consultation. The docket
for this rule contains more information on possible considerations.
    The EPA's proposed rule provides that the criteria calculator,
which incorporates pH, DOC, and total hardness as input parameters, be
used to calculate protective acute and chronic aluminum criteria values
for a site as set forth in the final 2018 recommended national
criteria. These calculated criteria values would protect aquatic life
under the full range of ambient conditions found at each site,
including conditions when aluminum is most toxic given the spatial and
temporal variability of the water chemistry at the site.
Characterization of the parameters that affect the bioavailability, and
associated toxicity, of aluminum is the primary feature to determine
protectiveness of aquatic life at a site at any given time. Oregon will
need to use ambient water chemistry data (i.e., pH, DOC, total
hardness) as inputs to the model in order to determine protective
aluminum criteria values for specific sites, unless the State develops
default values to be used in implementation. Oregon has the discretion
to select the appropriate method to reconcile model outputs and
calculate the final criteria values for each circumstance as long as
the resulting calculated criteria values shall protect aquatic life
throughout the site and throughout the range of spatial and temporal
variability, including when aluminum is most toxic. The EPA strongly
recommends that the State develop implementation materials to outline
its approach.
    The EPA suggests three methods that the State could use to
reconcile model outputs and calculate criteria values that will result
in protection of aquatic life at a site. Alternatively, the State may
use its own alternate methods to reconcile outputs to generate
protective criteria values. The appropriate method for each
circumstance will depend primarily on data availability.
    With method one, users identify protective criteria values by
selecting one or more individual model outputs based upon spatially and
temporally representative site-specific measured values for model
inputs. Method one can be used where input datasets are complete and
inputs are measured frequently enough to statistically represent
changes in the toxicity of aluminum, including conditions under which
aluminum is most toxic. In this case, the criteria values are
determined by selecting one or more individual outputs that will be
protective of aquatic life under the full range of ambient conditions,
including conditions of high aluminum toxicity. Method one could be
used to also establish criteria values to apply on a seasonal basis
where the data are sufficient.
    When using method two, users calculate protective criteria values
from the lowest 10th percentile of the distribution of individual model
outputs, based upon spatially and temporally representative site-
specific measured model input values. While the 10th percentile of
outputs should be protective in a majority of cases, certain
circumstances may warrant use of a more stringent model output (e.g.,
consideration of listed species). Sufficient data to characterize the
appropriate distribution of model outputs are necessary to derive a
protective percentile so that the site is protected under conditions of
high aluminum toxicity.
    In method three, users select the lowest model outputs (the lowest
CMC and the lowest CCC) calculated from spatially and temporally
representative input datasets that capture the most toxic conditions at
a site as the criteria values. Method three should be used where ten or
fewer individual model outputs are available.
    The EPA solicits comments on these methods and any other
scientifically defensible methods that could be used to select criteria
values to protect aquatic life by reconciling model outputs, as well as
whether the Agency should promulgate any or all of these suggested
methods for Oregon as part of this rulemaking.
    Additionally, the EPA solicits comment on promulgating ecoregional
default criteria values for aluminum in the final rule to ensure
protection of the designated use when available data are insufficient
to characterize a site.
    The EPA calculated ecoregional default aluminum criteria values
from measured pH and measured or estimated DOC and total hardness based
on existing concentrations of these variables in waters within each of
Oregon's Level III Ecoregions.\15\ These defaults are provided in Table
1 below.
---------------------------------------------------------------------------

    \15\ USEPA. 2013. U.S. Environmental Protection Agency, 2013,
Level III ecoregions of the continental United States: Corvallis,
Oregon, U.S. EPA--National Health and Environmental Effects Research
Laboratory, map scale 1:7,500,000, http://www.epa.gov/wed/pages/ecoregions/level_iii_iv.h. Omernik, J.M. 1987. Ecoregions of the
conterminous United States. Annals of the Association of American
Geographers 77:118-125.

Table 1--Ecoregional Default Aluminum Criteria Values for Each Level III
                           Ecoregion in Oregon
------------------------------------------------------------------------
                                                       CMC        CCC
                Level III Ecoregion                 ([mu]g/L)  ([mu]g/L)
------------------------------------------------------------------------
1 Coast Range.....................................        680        350
3 Willamette Valley...............................        870        440
4 Cascades........................................        600        350
9 Eastern Cascades Slopes and Foothills...........       1100        600
10 Columbia Plateau...............................       1400        840
11 Blue Mountains.................................       1300        780
12 Snake River Plain..............................       3000       1200
78 Klamath Mountains..............................       1300        780
80 Northern Basin and Range.......................       1400        790
------------------------------------------------------------------------

    To calculate ecoregional default criteria values, the EPA relied on
publicly available data (U.S. Geological Survey (USGS) National Water
Information System (NWIS); Oregon DEQ) \16\ collected in accordance
with quality assurance procedures established by each collecting
entity. From 2001-2015, a total of 19,274 samples across all Level III
Ecoregions in Oregon provided adequate data to calculate corresponding
acute and chronic criteria magnitudes. Adequate data to calculate
criteria magnitudes included samples with paired measurements of pH,
DOC, and total hardness, where available (1,689 samples). When paired
measurements of pH, DOC, and total hardness were not available, the EPA
paired empirical pH measurements with DOC and/or total hardness data
estimated from measured Total Organic Carbon (TOC) and specific
conductivity, respectively (17,585 samples). The EPA used DOC and total
hardness estimates to expand

available data and better represent the potential distribution of
criteria magnitudes across Level III Ecoregions in Oregon. The
calculation of the default criteria values presented here incorporates
the EPA's effort to closely follow Oregon DEQ's approach to developing
default DOC input values for Oregon's copper aquatic life criteria
rule. More information on the data sources and transformations is
available in the docket for this proposal. The EPA then calculated the
10th percentile CMC and CCC for each ecoregion from the distributions
of model outputs. The EPA selected the 10th percentile as a statistic
that represents a lower bound of spatially and temporally variable
conditions that will be protective in the majority of cases.
---------------------------------------------------------------------------

    \16\ USGS NWIS, https://waterdata.usgs.gov/nwis. Oregon
Wastewater Permits Database, http://www.deq.state.or.us/wq/sisdata/sisdata.asp.
---------------------------------------------------------------------------

    The EPA solicits comments on the Agency's use of the 10th
percentile of the ecoregional model output distributions of the
measured and transformed data to derive ecoregional default aluminum
criteria values. The EPA also solicits comment on whether a different
percentile of the model output distribution should be used, or if
combined ecoregional (georegional) distributions of outputs should be
used instead of the Level III ecoregional distributions to derive the
defaults. Additional information on the inputs used to derive outputs
and how the ecoregional default criteria values were selected using
percentiles of the model output distribution is provided in the
document entitled ``Analysis of the Protectiveness of Default
Ecoregional Aluminum Criteria Values'' which can be found in the
docket. The EPA solicits comment on alternative methods to developing
default ecoregional criteria values, as presented in the Analysis of
the Protectiveness of Default Ecoregional Aluminum Criteria Values. The
EPA solicits comment on the inclusion of such default criteria values
in the final rule. The EPA also solicits comment on whether there are
alternative approaches to ensure that protective model outcomes can be
identified for all waterbodies using the proposed criteria, and to ease
implementation.
    In addition to soliciting comment on including default ecoregional
criteria, the EPA also solicits comment on whether the Agency should
include default DOC input values in the final rule. Among the input
parameters, ambient data are least likely to be available for DOC. DOC
influences aluminum toxicity unidirectionally. Higher levels of DOC
provide more mitigation of aluminum toxicity. For water bodies for
which sufficient pH and total hardness data are available, but DOC data
are not available, the EPA solicits comment on whether to promulgate in
the final rule the default DOC input values provided in Table 2. If the
EPA were to promulgate both the default ecoregional aluminum criteria
values provided in Table 1 and the default DOC input values in Table 2,
in addition to the EPA's the calculation of CMC and CCC freshwater
aluminum criteria values for a site using the final 2018 recommended
national criteria, the State could choose to use the default
ecoregional aluminum criteria values or use the default DOC input
values in Table 2 and calculate criteria. The default DOC input values
could be used in combination with measured data for pH and total
hardness to calculate aluminum criteria outputs that are more specific
to site conditions than the ecoregional default criteria values
provided in Table 1. The EPA derived the default DOC input values as
the 15th or 20th percentile of the distribution of data from a
compilation of high quality data available for Oregon's georegions
(aggregated ecoregions with similar water quality characteristics),
compiled by Oregon DEQ and the US Geological Survey (see the ``Analysis
of the Protectiveness of Default Dissolved Organic Carbon Options,''
which can be found in the docket.) The calculation of the default DOC
input values presented in this preamble reflects the EPA's effort to
closely follow Oregon DEQ's approach to developing default DOC input
values for Oregon's copper aquatic life criteria rule. The EPA selected
the 15th or 20th percentiles as low-end percentile of georegional DOC
concentrations as a statistic that represents a lower bound of
spatially and temporally variable conditions that will be protective in
the majority of cases. The use of default DOC input values would ensure
protection of the designated use when site-specific ambient DOC inputs
are unavailable. Additional information on the derivation of the
default DOC input values is provided in the Analysis of the
Protectiveness of Default Dissolved Organic Carbon Options, which can
be found in the docket.
    The EPA solicits comments on the Agency's use of the 15th and 20th
percentiles of the georegional distributions of the available US
Geological Survey and Oregon DEQ DOC data to derive default DOC input
values for calculating aluminum outputs when DOC data are unavailable.
More information on the data and input analysis is available in the
Analysis of the Protectiveness of Default Dissolved Organic Carbon
Options. The EPA solicits comment on alternative methods to developing
default DOC input values, as presented in the Analysis of the
Protectiveness of Default Dissolved Organic Carbon Options. The EPA
also solicits comments on using default DOC input values based on a
different percentile, such as the 5th or 25th percentile of the
distribution (or another protective percentile within that range), as
well as using default DOC values for ecoregions rather than georegions.

                         Table 2--Default DOC Input Values for Each Georegion in Oregon
----------------------------------------------------------------------------------------------------------------
              EPA ecoregion                     ODEQ georegion                Percentile            DOC (mg/L)
----------------------------------------------------------------------------------------------------------------
Willamette Valley (03)..................  Willamette................  15th......................            0.83
Coast Range (01)........................  Coastal...................  20th......................            0.83
Klamath Mountains (78)..................
Cascades (04)...........................  Cascades..................  20th......................            0.83
Eastern Cascades Slopes (09)............  Eastern...................  15th......................            0.83
Columbia Plateau (10)...................
Northern Basin and Range (80)...........
Blue Mountains (11).....................
Snake River Plain (12)..................
NA......................................  Columbia River............  20th......................            1.39
----------------------------------------------------------------------------------------------------------------

    The EPA is not considering the development of default input values
for pH and total hardness because the relationship between these
parameters and aluminum toxicity is not unidirectional, which means
that a

given percentile of pH and total hardness may be conservative in some
circumstances but not others (see the EPA's final 2018 recommended
national criteria document for more information). Also, data for these
parameters are more likely to be available (Analysis of the
Protectiveness of Default Dissolved Organic Carbon Options). Given the
complex nature of aluminum toxicity and how it dynamically varies with
water chemistry (especially with pH and total hardness), it is not
possible to calculate a universally protective set of water chemistry
conditions in cases where the water chemistry is unknown. For example,
total hardness at low pH tends to increase criteria magnitudes whereas
total hardness at high pH tends to reduce criteria magnitudes. That
relationship is also dependent on DOC concentration (see final 2018
recommended national criteria document for further details). Therefore,
measured pH and total hardness data are essential to calculate reliable
aluminum criteria.

C. Implementation of Proposed Freshwater Acute and Chronic Aluminum
Criteria in Oregon

    This proposal, if finalized, would likely be the first occasion
that a state or authorized tribe would have aluminum criteria based on
the final 2018 recommended national criteria. The EPA understands that
states have certain flexibility under 40 CFR part 131 with how they
implement water quality standards such as these aluminum criteria. The
EPA is recommending possible approaches below for the State's
consideration and for public comment. The State may choose to use these
recommendations or to implement the final aluminum criteria in other
ways that are consistent with 40 CFR part 131.
    For NPDES permitting, monitoring and assessment, and total maximum
daily load (TMDL) development purposes, the State can use different
methods to process model outputs in order to generate criteria values
for a specific site, as discussed in section III.B. Because of this
flexibility, the State should ensure public transparency and
predictable, repeatable outcomes. When Oregon calculates aluminum
criteria values, the EPA recommends that the State make each site's
ambient water chemistry data, including the inputs used in the aluminum
criteria value calculations, resultant criteria values, and the
geographic extent of the site, publicly available on the State's
website.
    Where a NPDES permitted discharge is present, the EPA recommends
that Oregon ensure that sufficiently representative ambient pH, DOC,
and total hardness data are collected to have confidence that
conditions in the water body are being adequately captured both
upstream of and downstream from the point of discharge. The State
should use the criteria calculated values that will be protective at
the most toxic conditions to develop water quality-based effluent
limits (WQBELs). Input parameter values outside the empirical ranges of
the MLR models (as identified in sections 2.7.1 and 5.3.6 of the final
2018 recommended national criteria document) may indicate other
potential toxicity issues at a site. When input parameters fall outside
those stated ranges, the EPA makes the following recommendations that
the State could implement for the protection of designated uses. NPDES
permit conditions could include: (1) Additional monitoring approaches
such as Whole Effluent Toxicity (WET) testing or biological monitoring;
and (2) increased frequency of input parameter and aluminum
concentration monitoring. Once criteria values protective of the most
toxic conditions are calculated, critical low flows for the purposes of
dilution of the pollutant concentration in effluent, combined with
critical effluent concentrations of the pollutant, may be used to
establish whether there is reasonable potential for the discharge to
cause or contribute to an excursion above the applicable criteria and
therefore, a need to establish WQBELs, per the EPA's NPDES Permit
Writers' Manual.\17\ Critical low flows and mixing zones for NPDES
permitting purposes are further discussed in Section IV.
---------------------------------------------------------------------------

    \17\ USEPA. 2010. NPDES Permit Writers' Manual. U.S.
Environmental Protection Agency, Office of Water, Washington, DC
EPA-833-K-10-001. September 2010.
---------------------------------------------------------------------------

    In addition, for transparency the EPA recommends that Oregon
describe in its NPDES permit fact sheets or statements of basis how the
criteria values were calculated, including the input data or summary of
input data and source of data. The EPA also recommends that the fact
sheets or statements of basis include descriptions of how the criteria
values were used to determine whether there is reasonable potential for
the discharge to cause or contribute to an excursion above the criteria
(``reasonable potential'') and if so, how they were used to derive
WQBELs. Similarly, for TMDLs, the EPA recommends that Oregon describe
in the TMDL document how the criteria values were calculated and used
to determine TMDL targets. In the assessment and impaired waters
listing context, the EPA recommends that Oregon describe how it
calculated criteria values and the process used to make water quality
attainment decisions in the assessment methodology for the Integrated
Report.\18\
---------------------------------------------------------------------------

    \18\ The Integrated Report is intended to satisfy the listing
requirements of Section 303(d) and the reporting requirements of
Sections 305(b) and 314 of the Clean Water Act (CWA).
---------------------------------------------------------------------------

    The water quality conditions that determine the bioavailability and
toxicity of metals, including aluminum, are unique to each site and can
vary widely in both space and time, changing with biological activity,
flow, geology, human activities, watershed landscape, and other
features of the water body. It is important that the State capture the
spatial and temporal variability at sites, and consider establishment
of site boundaries carefully. As mentioned above in Section III. B.,
Oregon should ensure that sufficiently representative data are
collected for the model's input parameters (pH, DOC, and total
hardness) to have confidence that the most toxic conditions are
adequately characterized. To accomplish this, Oregon may evaluate the
input parameter data and resultant criteria values that are calculated
over time for different flows and seasons through the use of
appropriate analytical methods, such as a Monte Carlo \19\ simulation
or another analytical tool. Also, when defining a site to which to
apply criteria for aluminum, the EPA recommends that Oregon consider
that metals are generally persistent, so calculating a criterion value
using input parameter values from a location at or near the discharge
point could result in a criterion value that is not protective of areas
that are outside of that location. For example, if downstream waters
have different pH conditions that might increase aluminum toxicity
downstream from the facility, the permit should account for that. The
EPA also recommends that Oregon consider that as the size of a site
increases, the spatial and temporal variability is likely to increase;
thus, more water samples may be required to adequately characterize the
entire site.
---------------------------------------------------------------------------

    \19\ Given sufficient data, Monte Carlo simulation or equivalent
analysis such as bootstrapping can be used to determine the
probability of identifying the most toxic time period for a series
of monitoring scenarios. From such an analysis, the State can select
the appropriate monitoring regime.
---------------------------------------------------------------------------

    Substantial changes in a site's ambient input parameter
concentrations will likely affect aluminum toxicity and the relevant
criteria values for aluminum at that site. In addition, as a robust,
site-specific dataset is developed with regular monitoring, criteria
values can be updated to more accurately

reflect site conditions. Therefore, the EPA recommends that Oregon
revisit each water body's aluminum criteria values periodically (for
example, with each CWA section 303(d) listing cycle or WQS triennial
review) and re-run the models when changes in water chemistry are
evident or suspected at a site and as additional monitoring data become
available. This will ensure that the criteria values accurately reflect
the toxicity of aluminum and maintain protective values.
    The State may use multiple methods to calculate site-specific
criteria values in order to implement the criteria for CWA purposes.
For example, the State could use Method one, after collecting
sufficiently representative model input data for all parameters, as
well as corresponding ambient aluminum measurements as described in
section III.B, to determine whether the paired aluminum measurements
exceed the calculated model output magnitude more than once in three
years for assessment purposes. Alternatively, the State could use the
output dataset to select a single CMC and a single CCC that are
sufficiently protective at the most toxic conditions for the purposes
of permitting an aluminum discharge or establishing a TMDL. In
contrast, using Methods two or three, the State could calculate a
single numeric expression of the criteria that would be the basis for
all monitoring, assessment, TMDL, and NPDES permitting purposes.

D. Incorporation by Reference

    The Agency is proposing that the final EPA regulatory text
incorporate one EPA document by reference. In accordance with the
requirements of 1 CFR 51.5, the EPA is proposing to incorporate by
reference the EPA's Final Aquatic Life Ambient Water Quality Criteria
for Aluminum 2018 (EPA 822-R-18-001), discussed in Section III.A of
this preamble. Incorporating this document by reference will allow the
State to access all of the underlying information and data the EPA used
to develop the final 2018 recommended national criteria. With access to
this information, the State will have the flexibility to create its own
version of the calculator built upon the underlying peer-reviewed
model. The EPA has made, and will continue to make, this document
generally available electronically through www.regulations.gov at the
docket associated with this rulemaking and at https://www.epa.gov/wqc/aquatic-life-criteria-aluminum.

IV. Critical Low Flows and Mixing Zones

    To ensure that the proposed criteria are applied appropriately to
protect Oregon's aquatic life uses, the EPA recommends Oregon use
critical low flow values consistent with longstanding EPA guidance \20\
when calculating the available dilution for the purposes of determining
the need for and establishing WQBELs in NPDES permits. Dilution is one
of the primary mechanisms by which the concentrations of contaminants
in effluent discharges are reduced following their introduction into a
receiving water. During a low flow event, there is less water available
for dilution, resulting in higher instream pollutant concentrations. If
criteria are implemented using inappropriate critical low flow values
(i.e., values that are too high), the resulting ambient concentrations
could exceed criteria values when low flows occur.\21\
---------------------------------------------------------------------------

    \20\ USEPA. 1991. Technical Support Document For Water Quality-
based Toxics Control. U.S. Environmental Protection Agency, Office
of Water, Washington, DC EPA/505/2-90-001. http://www3.epa.gov/npdes/pubs/owm0264.pdf.
    \21\ USEPA. 2014. Water Quality Standards Handbook-Chapter 5:
General Policies. U.S. Environmental Protection Agency, Office of
Water. Washington, DC EPA-820-B-14-004. http://www.epa.gov/sites/production/files/2014-09/documents/handbook-chapter5.pdf.
---------------------------------------------------------------------------

    The EPA notes that in ambient settings, critical low flow
conditions used for NPDES permit limit derivation purposes may not
always correspond with conditions of highest aluminum bioavailability
and toxicity. The EPA's NPDES Permit Writers' Manual describes the
importance of characterizing effluent and receiving water critical
conditions, because if a discharge is controlled so that it does not
cause water quality criteria to be exceeded in the receiving water
under critical conditions, then water quality criteria should be
attained under all other conditions.\22\ The State's implementation
procedures should clearly define how the State will consider critical
conditions related to critical low flows and the greatest aluminum
bioavailability and toxicity to ensure that reasonable potential is
assessed and, if needed, appropriate permit limits are established that
fully protect aquatic life uses under the full range of ambient
conditions.
---------------------------------------------------------------------------

    \22\ The same principle holds for developing a TMDL target.
---------------------------------------------------------------------------

    The EPA's March 1991 Technical Support Document for Water Quality-
based Toxics Control recommends two methods for calculating acceptable
critical low flow values: The traditional hydrologically-based method
developed by the USGS and a biologically based method developed by the
EPA.\23\ The hydrologically-based critical low flow value is determined
statistically, using probability and extreme values, while the
biologically-based critical low flow is determined empirically using
the specific duration and frequency associated with the criterion. For
the acute and chronic aluminum criteria, the EPA recommends the
following critical low flow values, except where modeling demonstrates
that the most significant critical conditions occur at other than low
flow:
---------------------------------------------------------------------------

    \23\ USEPA. 1991. Technical Support Document For Water Quality-
based Toxics Control. U.S. Environmental Protection Agency, Office
of Water, Washington, DC EPA/505/2-90-001. http://www3.epa.gov/npdes/pubs/owm0264.pdf.

Acute Aquatic Life (CMC): 1Q10 or 1B3
Chronic Aquatic Life (CCC): 7Q10 or 4B3

    Using the hydrologically-based method, the 1Q10 represents the
lowest one-day average flow event expected to occur once every ten
years, on average, and the 7Q10 represents the lowest seven-
consecutive-day average flow event expected to occur once every ten
years, on average. Using the biologically-based method, 1B3 represents
the lowest one-day average flow event expected to occur once every
three years, on average, and 4B3 represents the lowest four-
consecutive-day average flow event expected to occur once every three
years, on average.\24\ The EPA seeks comment on whether the Agency
should promulgate these acute and chronic critical low flow values in
the final rule or should promulgate alternative critical low flow
values.
---------------------------------------------------------------------------

    \24\ See USEPA, 2014.
---------------------------------------------------------------------------

    The criteria in this proposed rule, once finalized, must be
attained at the point of discharge unless Oregon authorizes a mixing
zone. Where Oregon authorizes a mixing zone, the criteria would apply
at the locations allowed by the mixing zone (i.e., the CMC would apply
at the defined boundary of the acute mixing zone and the CCC would
apply at the defined boundary of the chronic mixing zone).\25\
---------------------------------------------------------------------------

    \25\ See USEPA, 1991.
---------------------------------------------------------------------------

V. Endangered Species Act

    The EPA's final 2018 recommended national criteria for aluminum
represent the best available science. The EPA proposes to promulgate
acute and chronic aquatic life aluminum criteria for Oregon based on
the EPA's final 2018 recommended national criteria. The EPA is
proposing these criteria pursuant to CWA section 303(c)(4)(A),

as described in Section II.A of this document, and in compliance with
the consent decree described in Section II.B of this document. 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. The EPA has initiated ESA consultation on this
proposed action and will continue to work closely with NMFS and USFWS
to ensure that any acute and chronic aluminum criteria that the Agency
finalizes are not likely to jeopardize the continued existence of any
endangered or threatened species or result in the destruction or
adverse modification of designated critical habitat in Oregon. The EPA
will continue ESA consultation with NMFS and USFWS while the Agency
develops final aluminum criteria for Oregon that are consistent with
the requirements of ESA section 7(a)(2), as well as with the EPA's
Aquatic Life Guidelines.

VI. Under what conditions will Federal standards not be promulgated or
be withdrawn?

    Under the CWA, Congress gave states and authorized tribes primary
responsibility for developing and adopting WQS for their navigable
waters (CWA section 303(a)-(c)). Although the EPA is proposing aluminum
aquatic life criteria for Oregon's fresh waters to remedy the Agency's
2013 disapproval of Oregon's 2004 criteria, Oregon continues to have
the option to adopt and submit to the Agency acute and chronic aluminum
criteria for the State's fresh waters consistent with CWA section
303(c) and the Agency's implementing regulation at 40 CFR part 131. The
EPA encourages Oregon to expeditiously adopt protective aluminum
aquatic life criteria. Consistent with CWA section 303(c)(4), if Oregon
adopts and submits aluminum aquatic life criteria, and the EPA approves
such criteria before finalizing this proposed rule, the Agency would
not proceed with the promulgation for those waters and/or pollutants
for which the Agency approves Oregon's criteria. Under those
circumstances, federal promulgation would no longer be necessary to
meet the requirements of the Act.
    If the EPA finalizes this proposed rule, and Oregon subsequently
adopts and submits aluminum aquatic life criteria, the Agency would
approve the State's criteria if those criteria meet the requirements of
section 303(c) of the CWA and the Agency'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 Agency withdraws those federally-
promulgated standards. The EPA would expeditiously undertake such a
rulemaking to withdraw the federal criteria if and when Oregon adopts,
and the Agency approves corresponding criteria that meet the
requirements of section 303(c) of the CWA and the EPA's implementing
regulation at 40 CFR part 131. 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 and Implementation Mechanisms

    The federal WQS regulation at 40 CFR part 131 provides several
tools that Oregon has available to use at its discretion when
implementing or deciding how to implement these aquatic life criteria,
once finalized. Among other things, the EPA's WQS regulation: (1)
Specifies how states and authorized tribes establish, modify, or remove
designated uses (40 CFR 131.10); (2) specifies the requirements for
establishing criteria to protect designated uses, including criteria
modified to reflect site-specific conditions (40 CFR 131.11); (3)
authorizes and provides regulatory guidelines for states and authorized
tribes to adopt WQS variances that provide time to achieve the
applicable WQS (40 CFR 131.14); 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 (40 CFR 131.15). Each of
these approaches are discussed in more detail in the next sections.
Whichever approach a state pursues, however, all NPDES permits would
need to comply with the EPA's regulations at 40 CFR 122.44(d)(1)(i).

A. Designating Uses

    The EPA's proposed aluminum criteria apply to fresh waters in
Oregon where the protection of fish and aquatic life is a designated
use (see Oregon Administrative Rules at<PHONE_NUMBER>, Table 30). The
federal regulation at 40 CFR 131.10 provides regulatory requirements
for establishing, modifying, and removing designated uses. If Oregon
removes designated uses such that no fish or aquatic life uses apply to
any particular water body affected by this rule and adopts the highest
attainable use,\26\ the State 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 finds
removal or modification of the designated use and the adoption of the
highest attainable use and criteria to protect that use to be
consistent with CWA section 303(c) and the implementing regulation at
40 CFR part 131, the Agency would approve the revised WQS. The EPA
would then undertake a rulemaking to withdraw the corresponding federal
WQS for the relevant water(s).
---------------------------------------------------------------------------

    \26\ If a state or authorized tribe adopts a new or revised WQS
based on a required 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)).
---------------------------------------------------------------------------

B. WQS Variances

    Oregon's WQS provide sufficient authority to apply WQS variances
when implementing federally promulgated criteria for aluminum, as long
as such WQS variances are adopted consistent with 40 CFR 131.14 and
submitted to the EPA for review under CWA section 303(c). Federal
regulations at 40 CFR 131.3(o) define 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 25.5)
provide a flexible but defined pathway for states and authorized tribes
to comply with NPDES permitting requirements, while providing
dischargers with the time they need to meet a WQS that is 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 (HAC) 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 provide a legal
avenue by which NPDES permit limits can be written to comply with the
WQS variance rather than the underlying WQS for the 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
regulation allows the State to adopt a subsequent WQS variance if it is
adopted consistent with 40 CFR 131.14. The EPA is proposing a criterion
that applies to use designations that Oregon has already established.
Oregon's WQS regulations currently include the authority to use WQS
variances when implementing criteria, as long as such WQS variances are
adopted consistent with 40 CFR 131.14. Oregon may use the EPA-approved
WQS variance procedures when adopting such WQS variances.

C. NPDES Permit Compliance Schedules

    The EPA's regulations at 40 CFR 122.47 and 40 CFR 131.15 address
how permitting authorities can use permit compliance schedules in NPDES
permits if dischargers need additional time to undertake actions like
facility upgrades or operation changes to meet their WQBELs based on
the applicable WQS. 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, in order
to provide a discharger with additional time to meet its WQBELs
implementing applicable WQS. The EPA's regulation at 40 CFR 131.15
requires that states that intend 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). Oregon already has an
EPA-approved provision authorizing the use of permit compliance
schedules (see OAR<PHONE_NUMBER>), consistent with 40 CFR 131.15. That
State provision is not affected by this rule. Oregon is authorized to
grant permit compliance schedules, as appropriate, based on the federal
criteria, as long as such permit compliance schedules are consistent
with the EPA's permitting regulation at 40 CFR 122.47.

VIII. Economic Analysis

    The proposed criteria would serve as a basis for development of new
or revised NPDES permit limits in Oregon for regulated dischargers
found to have reasonable potential to cause or contribute to an
excursion of the proposed aluminum criteria. However, the EPA cannot
anticipate how Oregon would chose to calculate criteria values based on
the proposed criteria and what impact they would have on dischargers.
Oregon also has NPDES permitting authority, and retains discretion in
implementing standards. While Oregon may choose to incorporate the
ecoregional default criteria values (from Table 1) directly into
certain permits, it has other options available to it as well as
discussed in section III.C. For example, the State can calculate
criteria values using ambient data. Furthermore, if the State
calculates criteria values using ambient data in the model, the State
can choose its own method of reconciling multiple outputs. Despite this
discretion, if Oregon determines that a permit is necessary, such
permit would need to comply with the EPA's regulations at 40 CFR
122.44(d)(1)(i). Still, to best inform the public of the potential
impacts of this proposed rule, the EPA made some assumptions to
evaluate the potential costs associated with State implementation of
the EPA's proposed criteria. The EPA chose to evaluate the expected
costs associated with State implementation of the Agency's proposed
aluminum criteria based on available information. This analysis is
documented in Economic Analysis for the Proposed Rule: Aquatic Life
Criteria for Aluminum in Oregon, which can be found in the record for
this rulemaking. The EPA seeks public comment on all aspects of the
economic analysis including, but not limited to, its assumptions
relating to the baseline criteria, affected entities, implementation,
and compliance costs.
    For the economic analysis, the EPA assumed that in the baseline,
Oregon fully implements existing water quality criteria (i.e.,
``baseline criteria'') and then estimated the incremental impacts for
compliance with the aluminum criteria in this proposed rule. As Oregon
has not promulgated numeric aquatic life criteria for aluminum, the
``baseline criteria'' for aluminum are assumed to be the State's
narrative criteria. Because the baseline criteria are narrative, and
because few data on aluminum NPDES discharges and assessments are
available, there is uncertainty regarding how to numerically express
the baseline criteria. The EPA therefore, assumed that the narrative
criteria are fully implemented, and in the absence of information to
the contrary, the EPA had to make assumptions based on the available
data to determine how to attribute costs to comply with the numeric
aluminum criteria in this proposed rule. For point source costs, the
EPA assumed any NPDES-permitted facility that discharges aluminum and
is found to have reasonable potential would be subject to effluent
limits and would incur compliance costs if it chose to continue
operating. The types of affected facilities include industrial
facilities, drinking water treatment plants, and publicly owned
treatment works (POTWs) discharging sanitary wastewater to surface
waters (i.e., point sources). For nonpoint sources, those that
contribute aluminum loadings to waters that would be considered
impaired for aluminum under the proposed criteria may incur incremental
costs for additional best management practices (BMPs). It is possible
that the narrative criteria are not being fully implemented; in that
case, some of the impacts and costs assumed to be attributed to this
proposal in this analysis would actually be baseline costs, and thus
the costs here would be overestimated.

A. Identifying Affected Entities

    To evaluate potential costs to NPDES-permitted facilities and the
potential for impaired waters, the EPA used the ecoregional default
criteria values, calculated from the 10th percentile of the
distribution of individual MLR-based calculated criteria outputs for
each of Oregon's nine Level III ecoregions, as provided in Table 1. EPA
is not proposing these default values as a component of Oregon's
aluminum criteria, but is soliciting comment on whether EPA should
include them in Oregon's final criteria. For the purposes of this
economic analysis, the EPA refers to the ecoregional default criteria
values as the ``economic analysis criteria.'' The economic analysis
criteria are likely different from and possibly lower (more stringent)
than the actual site-specific criteria that Oregon would calculate
using ambient data from each water body and therefore, may be
conservative cost estimates. As described earlier in this proposed
rule, the EPA recommends that Oregon collect sufficiently
representative ambient data to calculate the most accurate and
protective aluminum criteria values.
    The EPA identified one point source facility, a major discharger,
with

sufficient data for evaluation \27\ of reasonable potential and
therefore potentially be affected by the rule. The EPA also identified
one minor facility with aluminum effluent limits, however, aluminum
effluent data are not available in ICIS-NPDES for the EPA to readily
evaluate this facility. The EPA did not include facilities covered by
general permits in its analysis because none of the general permits
reviewed include specific effluent limits or monitoring requirements
for aluminum. Because of the lack of data for aluminum in point source
discharges in the State, along with the potential incremental
impairments described below, the EPA took additional steps to identify
potential costs for point source dischargers that utilize aluminum in
their operations. These steps focused on facilities in specific
industries that could be affected by the rule: Aluminum anodizing
facilities, drinking water treatment plants, and wastewater treatment
facilities. For these facilities, the EPA considered both additional
controls and product substitution. This analysis supplements the
standard analysis that uses data from specific facilities in Oregon to
determine potential point source costs based on reasonable potential to
cause or contribute to an exceedance of a WQS. See the Economic
Analysis for more details.
---------------------------------------------------------------------------

    \27\ The EPA initially used ICIS-NPDES to identify facilities in
Oregon whose NPDES permits contain effluent limitations and/or
monitoring requirements for aluminum. The EPA obtained facility-
specific information from NDPES permits and fact sheets.
---------------------------------------------------------------------------

B. Method for Estimating Costs

    For the one NPDES-permitted facility with available data, the EPA
evaluated the reasonable potential to exceed the economic analysis
criteria. There was no reasonable potential to exceed the economic
analysis criteria and therefore no basis for estimating projected
effluent limitations based on reasonable potential analysis.
    For the supplemental point source analysis, the EPA evaluated
potential costs to three types of facilities that would incur costs
under the proposed rule if they were found to have reasonable potential
and were therefore subject to effluent limits. First, several aluminum
anodizing facilities discharge to local publicly owned treatment works
(POTWs). The proposed criteria could result in the POTWs establishing
local (pretreatment) limits for these aluminum anodizers. The EPA
identified two options for potential treatment upgrades that may be
required (countercurrent cascade rinsing and countercurrent cascade
rinsing plus chemical precipitation/flocculation). The EPA developed
cost estimates for each of those. Second, drinking water treatment
plants often use alum in treatment processes as a coagulant, and
discharge filter backwash that may contain aluminum. The proposed
criteria may result in the State's drinking water systems needing to
reduce aluminum concentrations in their wastewater discharges. For this
analysis, the EPA assumed that all water treatment plants in Oregon
that discharge directly to surface waters currently use alum as a
coagulant and estimated costs to the plants if they were to reduce
their wastewater discharges of aluminum and divert the aluminum to
sludge disposal. If these assumptions are incorrect, the costs
estimated here would be either an overestimate or an underestimate.
Third, wastewater treatment facilities often use chemical precipitation
followed by filtration to remove phosphorus from the wastewater prior
to discharge. The EPA examined the wastewater treatment facilities in
the State that have permit limits for total phosphorus and therefore
may use alum for phosphorus removal. The EPA assumed that these
facilities would substitute ferrous coagulants for the aluminum
coagulants, and estimated costs for that change.
    If waters were to be identified as impaired when applying the
economic analysis criteria, resulting in the need for TMDL development,
there could be some costs to nonpoint sources of aluminum. Using
available ambient monitoring data, the EPA compared total recoverable
aluminum concentrations to the economic analysis criteria, and
identified waterbodies that are potentially impaired. There are 826
samples across 260 stations. Note that the EPA was not able to identify
BMPs for aluminum and therefore cannot make an estimate of potential
nonpoint source costs associated with these discharges.

C. Results

    The NPDES-permitted facility for which monitoring data are
available does not have reasonable potential to exceed the economic
analysis criteria. Therefore, there are no data indicating that point
source dischargers will incur annual costs to comply with the proposed
rule.
    For the supplemental point source analysis, the EPA made both a
low-end and a high-end estimate for the costs to the State's 12
aluminum anodizers, based on two different technology upgrade options.
Without information to know which option each facility would choose if
they had to upgrade, the EPA estimated that if all 12 facilities
upgraded to countercurrent cascade rinsing technology, the total annual
cost would be $51,600 (at a 3% discount rate over the 20-year life of
the capital equipment). On the high end, the EPA estimated that if all
12 facilities upgraded to countercurrent cascade rinsing technology
plus chemical precipitation and settling, the total annual cost would
be $5.77 million (at a 3% discount rate over the 20-year life of the
capital equipment). For the 57 drinking water treatment plants assumed
to use alum as a coagulant, the EPA estimated the annual costs for
chemical and sludge disposal at $1.35 million (no additional capital
equipment). For the four wastewater treatment facilities currently
using alum as a coagulant, the EPA found that if they were to switch to
a ferrous coagulant, they would realize $0.64 million in annual cost
savings. Although the analysis would suggest potential cost savings,
the EPA assumes that, in absence of the proposed rule, the facilities
would already be using the lowest cost treatment. Therefore, the EPA
estimated that the rule would result in no change in cost for these
facilities. Because these estimates are based on assumed need for
control strategies simply based on the projected presence of aluminum
in various operations, with no specific knowledge of actual levels in
any waste stream, these costs are highly speculative.
    Based on available monitoring data and the economic analysis
criteria, water quality may be impaired for 53 stations. Without
additional information about how Oregon might categorize water bodies
for the purpose of defining reaches impaired for aluminum, the EPA
assumed that the 53 stations represent an upper bound on the number of
incremental TMDLs. It may be possible to combine TMDLs for common water
bodies (i.e., if the State decides to combine development of TMDLs for
a class of waters with impairments for similar causes) and reduce
development costs, though the EPA has no way to know in advance whether
the State will do this, or for how many waters. If there is water
quality impairment under the economic analysis criteria, there could be
costs for TMDL development. The EPA (2001) reports that the average
cost to develop a TMDL for a single source of impairment ranges from
$27,000 to $29,000 (in 2000 dollars) or $37,000 to $40,000 when updated
to 2017

dollars.\28\ TMDL development costs are one-time costs that the EPA
assumed would be uniformly spread out over several years (e.g., a 10-
year time period). Spread uniformly over a 10-year period, the annual
average costs for TMDL development would range from $196,000 to
$212,000 for the development of 53 TMDLs.
---------------------------------------------------------------------------

    \28\ These unit cost estimates derive from values provided in a
U.S. EPA draft report from 2001, entitled The National Costs of the
Total Maximum Daily Load Program (EPA 841-D-01-003), escalated to
$2017. The EPA used the Implicit Price Deflator for Gross Domestic
Product (from the Bureau of Economic Analysis to update the costs
(2000 = 78.078; 2017 = 107.948). These unit costs per TMDL represent
practices from nearly 20 years ago, and therefore, may not reflect
increased costs of analysis using more sophisticated contemporary
methods.
---------------------------------------------------------------------------

    Combining the potential costs for point source compliance from the
supplemental point source analysis with the incremental cost of TMDL
development, the total cost annualized at a 3% discount rate would
range from $1.6 million to $7.3 million for the first 10 years. The
cost would be slightly less in subsequent years after the TMDL
development is complete.\29\ The fully annualized costs of the rule
\30\ are $1.5 million to $7.2 million at a 3% discount rate; results at
the, 7% discount rate are included in the Economic Analysis for the
Proposed Rule: Aquatic Life Criteria for Aluminum in Oregon, but are
quite similar.
---------------------------------------------------------------------------

    \29\ After the 10-year period of TMDL development ends, the
annual costs would drop to $1.4 million to $7.1 million.
    \30\ That is, the costs when abstracting from the difference in
costs between the first ten years and subsequent years.
---------------------------------------------------------------------------

    Note that, while this analysis is based on the best publicly
available data and Oregon's current practices regarding water quality
impairments, it may not fully reflect the impact of the proposed
criteria to nonpoint sources and implementing authorities. If
additional monitoring data were available, or if ODEQ increases its
monitoring of ambient conditions in future assessment periods,
additional impairments may be identified under the baseline criteria
and/or final criteria. Conversely, there may be fewer waters identified
as impaired for aluminum after Oregon has fully implemented activities
to address sources of existing impairments for other contaminants
(e.g., metals in stormwater runoff from urban, industrial, or mining
areas).
    The total costs presented in the Economic Analysis for the Proposed
Rule: Aquatic Life Criteria for Aluminum in Oregon are a product of a
series of assumptions and subsequent analyses that are intended to be
both conservative and as comprehensive as possible. This proposed rule
includes several safeguards inherent in both how aluminum criteria
would be calculated for a given water body in practice, and in the
implementation of WQS, in general. Permitting procedures such as
reasonable potential analysis and TMDL development procedures ensure
that entities that are significant contributors and have the capability
of load reduction are properly identified and their impacts are
accurately quantified. Furthermore, WQS allow for consideration of
natural conditions, anthropogenic impacts that cannot be remedied, and
social and economic impacts of additional controls through discharger-
specific WQS variances and designated use modifications. In short,
there are systems in place to evaluate tradeoffs that are central to
any benefit-cost analysis. However, these tradeoffs cannot be evaluated
without a comprehensive set of WQS that address all important water
quality parameters. This and other analyses have demonstrated that
aluminum is among the important water quality parameters with respect
to supporting aquatic life designated uses. Numeric aluminum criteria
can help facilitate the consideration of tradeoffs between control
costs and the value of market and non-market use, and non-use benefits.

IX. Statutory and Executive Order Reviews

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

    As determined by the Office of Management and Budget (OMB), this
action is a significant regulatory action and was submitted to OMB for
review. Any changes made during OMB's review have been documented in
the docket. The EPA evaluated the potential costs to NPDES dischargers
associated with State implementation of the Agency's proposed criteria.
This analysis, Economic Analysis for the Proposed Rule: Aquatic Life
Criteria for Aluminum in Oregon, is summarized in section VIII of the
preamble and is available in the docket.

B. Executive Order 13771 (Reducing Regulations and Controlling
Regulatory Costs)

    This action is expected to be an Executive Order 13771 regulatory
action. Details on the estimated costs of this proposed rule can be
found in the EPA's analysis of the potential costs and benefits
associated with this action.

C. Paperwork Reduction Act

    This action does not impose an information collection burden under
the Paperwork Reduction Act. 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.

D. Regulatory Flexibility Act

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the Regulatory
Flexibility Act. 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) \31\ and the EPA's implementing
regulations at 40 CFR 122.44(d)(1) and 122.44(d)(1)(A) 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 WQS 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 regulations 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.'' As a result of this action, the
State of Oregon will need to ensure that permits it issues include any
limitations on discharges necessary to comply with the WQS established
in the final rule. In doing so, the State will have a number of choices
associated with permit writing. While Oregon'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.
---------------------------------------------------------------------------

    \31\ CWA section 301(b) Timetable for Achievement of Objectives
In order to carry out the objective of this chapter there shall be
achieved--(1)(C): 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 this title) or any other
Federal law or regulation, or required to implement any applicable
water quality standard established pursuant to this chapter.
---------------------------------------------------------------------------

E. Unfunded Mandates Reform Act

    This action contains no federal mandates under the provisions of
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C.
1531-1538 for state, local, or tribal governments or the private
sector. As these water quality criteria are not self-implementing, the
EPA's action imposes no enforceable duty on any state, local or tribal
governments or the private sector. Therefore, this action is not
subject to the requirements of sections 202 or 205 of the UMRA. This
action is also not subject to the requirements of section 203 of UMRA
because it contains no regulatory requirements that could significantly
or uniquely affect small governments.

F. Executive Order 13132 (Federalism)

    Under the technical requirements of Executive Order 13132, the EPA
has determined that this proposed rule may not have federalism
implications but believes that the consultation requirements of the
Executive Order have been satisfied in any event. On several occasions
over the course of September 2017 through February 2019, the EPA
discussed with the Oregon Department of Environmental Quality the
Agency's development of the federal rulemaking and clarified early in
the process that if and when the State decided to develop and establish
its own aluminum standards, the EPA would instead assist the State in
its process. During these discussions, the EPA explained the scientific
basis for the proposed criteria; the external peer review process and
the comments the Agency received on the revised CWA section 304(a)
criteria recommendation on which the proposed criteria are based; the
Agency's consideration of those comments and responses; possible
alternatives for criteria, including default criteria and input values;
and the overall timing of the federal rulemaking effort. The EPA took
these discussions with the State into account during the drafting of
this proposed rule. The EPA considered the State's initial feedback in
making the Agency's decision to propose the criteria as drafted and
solicit comment on the default criteria values and default DOC input
values as described in Section B. Proposed Acute and Chronic Aluminum
Criteria for Oregon's fresh waters of this proposed rulemaking.
    The EPA specifically solicits comments on this proposed action from
State and local officials.

G. 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
responsibilities between the federal government and tribes. Thus,
Executive Order 13175 does not apply to this action.
    Many tribes in the Pacific Northwest hold reserved rights to take
fish for subsistence, ceremonial, religious, and commercial purposes.
The EPA developed the criteria in this proposed rule to protect aquatic
life in Oregon from the effects of exposure to harmful levels of
aluminum. Protecting the health of fish in Oregon will, therefore,
support tribal reserved fishing rights, including treaty-reserved
rights, where such rights apply in waters under State jurisdiction.
    Consistent with the EPA Policy on Consultation and Coordination
with Indian Tribes, the Agency consulted with tribal officials during
the development of this action. The EPA has sent a letter to tribal
leaders in Oregon offering to consult on the proposed aluminum criteria
in this rule. The EPA will hold a conference call with tribal water
quality technical contacts and tribal officials to explain the Agency's
proposed action and timeline approximately two weeks after the proposal
is published and the comment period is initiated. The EPA will continue
to communicate with the tribes prior to its final action.

H. 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 Agency 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.

I. 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.

J. National Technology Transfer and Advancement Act of 1995

    This proposed rulemaking does not involve technical standards.

K. 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, once finalized, will
support the health and abundance of aquatic life in Oregon, and will
therefore benefit all communities that rely on Oregon's ecosystems.

List of Subjects in 40 CFR Part 131

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

    Dated: April 18, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set forth in the preamble, the 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. Add Sec.  131.[XX] to read as follows:

Sec.  131.[XX]  Aquatic life criteria for aluminum in Oregon.

    (a) Scope. This section promulgates aquatic life criteria for
aluminum in fresh waters in Oregon.
    (b) Criteria for aluminum in Oregon. The aquatic life criteria in
Table 1 apply to all fresh waters in Oregon to protect the fish and
aquatic life designated uses.

                    Table 1--Proposed Aluminum Aquatic Life Criteria for Oregon Fresh Waters
----------------------------------------------------------------------------------------------------------------
                                                                                Criterion continuous
             Metal                  CAS No.     Criterion maximum concentration      concentration (CCC) \3\
                                                     (CMC) \2\ ([micro]g/L)                ([micro]g/L)
----------------------------------------------------------------------------------------------------------------
Aluminum \1\..................         7429905  Acute (CMC) and chronic (CCC) freshwater aluminum criteria
                                                 values for a site shall be calculated using the 2018 Aluminum
                                                 Criteria Calculator (Aluminum Criteria Calculator V.2.0.xlsx,
                                                 or a calculator in R or other software package using the same
                                                 1985 Guidelines calculation approach and underlying model
                                                 equations as in the Aluminum Criteria Calculator V.2.0.xlsx) as
                                                 established in the EPA's Final Aquatic Life Ambient Water
                                                 Quality Criteria for Aluminum 2018 (EPA 822-R-18-001) \4\.
                                                 Calculator outputs shall be used to calculate criteria values
                                                 for a site that protect aquatic life throughout the site under
                                                 the full range of ambient conditions, including when aluminum
                                                 is most toxic given the spatial and temporal variability of the
                                                 water chemistry at the site.
----------------------------------------------------------------------------------------------------------------
\1\ The criteria for aluminum are expressed as total recoverable metal concentrations.
\2\ The CMC is the highest allowable one-hour average instream concentration of aluminum. The CMC is not to be
  exceeded more than once every three years. The CMC is rounded to two significant figures.
\3\ The CCC is the highest allowable four-day average instream concentration of aluminum. The CCC is not to be
  exceeded more than once every three years. The CCC is rounded to two significant figures.
\4\ EPA 822-R-18-001, Final Aquatic Life Ambient Water Quality Criteria for Aluminum 2018, is incorporated by
  reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a)
  and 1 CFR part 51. All approved material is available from U.S. Environmental Protection Agency, Office of
  Water, Health and Ecological Criteria Division (4304T), 1200 Pennsylvania Avenue NW, Washington, DC 20460;
  telephone number:<PHONE_NUMBER>, https://www.epa.gov/wqc/aquatic-life-criteria-aluminum. It is also available
  for inspection at the National Archives and Records Administration (NARA). For information on the availability
  of this material at NARA, call<PHONE_NUMBER> or go to www.archives.gov/federal-register/cfr/ibr-locations.html.

    (c) Applicability. (1) The criteria in paragraph (b) of this
section are the applicable acute and chronic aluminum aquatic life
criteria in all fresh waters in Oregon to protect the fish and aquatic
life designated uses.
    (2) The criteria established in this section are subject to
Oregon's general rules of applicability in the same way and to the same
extent as are other federally promulgated and state-adopted numeric
criteria when applied to fresh waters in Oregon to protect the fish and
aquatic life designated uses.
    (3) For all waters with mixing zone regulations or implementation
procedures, the criteria apply at the appropriate locations within or
at the boundary of the mixing zones and outside of the mixing zones;
otherwise the criteria apply throughout the water body including at the
end of any discharge pipe, conveyance or other discharge point within
the water body.

[FR Doc. 2019-08464 Filed 4-30-19; 8:45 am]
 BILLING CODE 6560-50-P