[Federal Register Volume 84, Number 84 (Wednesday, May 1, 2019)]
[Proposed Rules]
[Pages 18454-18468]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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

[[Page 18455]]

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: (202) 566-1198; email address: 
[email protected].

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

[[Page 18456]]

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

[[Page 18457]]

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

[[Page 18458]]

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

[[Page 18459]]

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

[[Page 18460]]

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

[[Page 18461]]

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

[[Page 18462]]

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),

[[Page 18463]]

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 340-041-8033, 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

[[Page 18464]]

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 340-041-0061), 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

[[Page 18465]]

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

[[Page 18466]]

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

[[Page 18467]]

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.

[[Page 18468]]



                    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: (202) 566-1143, 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 202-741-6030 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