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Federal Register / Vol. 86, No. 52 / Friday, March 19, 2021 / Rules and Regulations of Oregons fresh waters could be affected by this rule. To determine whether your facility or activities could be affected by this action, you should carefully examine this 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.
B. How did EPA develop this final rule?
EPA carefully considered the public comments and feedback received from interested parties on the proposal published in the Federal Register at 84
FR 18454 on May 1, 2019. EPA provided a 45-day public comment period and held two public hearings on June 11 and June 12, 2019, to provide clarification on the contents of the proposed rulemaking and to accept verbal public comments.
A total of eight organizations and individuals submitted comments either to the docket or during the public hearings on a range of issues prior to the close of the public comment period on June 17, 2019. Some comments addressed issues beyond the scope of this rule. Brief summaries of specific comments and EPAs responses are provided in this action. For a full accounting of the comments and the Agencys responses, see EPAs Response to Comments document in the official public docket for this rule.
II. Background
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A. Statutory and Regulatory Authority CWA Section 303c 33 U.S.C.
1313c directs states to adopt WQS for state waters subject to CWA jurisdiction.
CWA Section 303c2A provides that WQS shall consist of designated uses of the waters and water quality criteria based on those uses. EPAs implementing regulations at 40 CFR
131.11a1 provide that such criteria must be based on sound scientific rationale and must contain sufficient parameters or constituents to protect the designated use and for waters with multiple use designations, the criteria shall support the most sensitive use. In addition, 40 CFR 131.10b provides that in designating uses of a water body and the appropriate criteria for those uses, the state shall take into consideration the water quality standards of downstream waters and shall ensure that its water quality standards provide for the attainment and maintenance of the water quality standards of downstream waters.
States review applicable WQS at least once every three years and, if appropriate, revise or adopt new WQS
CWA Section 303c1; 40 CFR 131.20.

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Any new or revised WQS must be submitted to EPA for review and approval or disapproval CWA Sections 303c2A and c3; 40 CFR 131.20
and 131.21. If EPA disapproves a states new or revised WQS as not consistent with CWA requirements, the state has 90 days to adopt a revised WQS that adopts the changes specified by EPA to meet CWA requirements. If the state fails to do so, EPA must promptly propose and then, within 90 days, promulgate such WQS unless the state has adopted a revised or new WQS that EPA determines to be consistent with CWA requirements CWA Sections 303c3 and c4.
Under CWA Section 304a, EPA
periodically publishes national criteria recommendations for states to consider when adopting water quality criteria for particular pollutants to meet the CWA
Section 101a2 goal. When EPA has published recommended criteria, states should establish numeric water quality criteria based on the Agencys CWA
Section 304a recommended criteria, CWA Section 304a recommended criteria modified to reflect site-specific conditions, or other scientifically defensible methods 40 CFR
131.11b1. Water quality criteria must protect the designated use and be based on sound scientific rationale. For waters with multiple use designations, the criteria shall support the most sensitive use 40 CFR 131.11a1.
B. EPAs Disapproval of Oregons Freshwater Aluminum Criteria As explained in the preamble of the proposed rulemaking, EPA disapproved the States freshwater aluminum criteria in 2013 because the State had not supplied a scientific rationale for the pH
range under which the States criteria would apply, which differed from the applicable pH range specified in EPAs 1998 national CWA Section 304a recommended criteria for aluminum 84
FR 1845657, May 1, 2019 that existed at that time but have since been updated.
Under the terms of a consent decree as amended to resolve litigation in Northwest Environmental Advocates v.
U.S. EPA, 3:15cv00663BR D. Or.
2015, EPA is required, no later than six months after the date on which the National Marine Fisheries Service also known as National Oceanic and Atmospheric Administration NOAA
Fisheries issues its Biological Opinion on the aluminum criteria previously proposed by EPA, to either approve aluminum criteria to protect aquatic life in fresh waters submitted by Oregon or sign a notice for publication in the Federal Register to finalize the
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aluminum criteria EPA proposed for Oregon. NOAA Fisheries transmitted its Biological Opinion to EPA on July 1, 2020. Since Oregon has not yet adopted freshwater aluminum criteria to meet CWA requirements, EPA is promulgating freshwater aluminum criteria for Oregon waters in accordance with CWA Sections 303c3 and c4.
C. General Recommended Approach for Deriving Aquatic Life Criteria Under the Agencys CWA Section 304a authority, EPA develops national recommended criteria and methodologies to protect aquatic life and human health for specific pollutants and pollutant parameters.
EPA invites public comment on draft recommended criteria and methodologies and seeks scientific expert review before EPA finalizes them as formal national water quality criteria recommendations for states to consider when developing and adopting applicable water quality criteria. EPAs Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses referred to as the Aquatic Life Guidelines 2 describe the systematic way in which EPA
establishes concentrations for a pollutant in water that will support the aquatic life designated use.
Numeric criteria derived using EPAs Aquatic Life Guidelines are expressed as acute and chronic values representing short-term and long-term exposures, respectively. The combination of a criterion maximum concentration CMC, typically expressed as a onehour 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. An exceedance occurs when the average concentration over the duration of the averaging period is above the CMC or the CCC.
EPA based its maximum exceedance frequency recommendation of once every three years on the ability of aquatic ecosystems to recover from the exceedances.
The Aquatic Life Guidelines recommend reliance on toxicity test data from a minimum of eight taxa of aquatic organisms in order to derive 2 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. PB85227049.
https www.epa.gov/sites/production/files/201602/documents/guidelines-water-quality-criteria.pdf.

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