Aquatic Life Criteria for Aluminum in Oregon

Published date01 May 2019
Citation84 FR 18454
Record Number2019-08464
SectionProposed rules
CourtEnvironmental Protection Agency
Federal Register, Volume 84 Issue 84 (Wednesday, May 1, 2019)
[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.
                ---------------------------------------------------------------------------
                 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.
                ---------------------------------------------------------------------------
                 \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/).
                ---------------------------------------------------------------------------
                 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 SSchedules
                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
                

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