Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 22555 

and ensure that assessments provide 

timely, actionable feedback to students, 

parents, and educators. The proposed 

priority for developing innovative 

assessment item types and design 

approaches, including the development 

of modular assessments, would yield 

new, more authentic methods for 

collecting evidence about what students 

know and are able to do and provide 

educators with more individualized, 

easily integrated assessments that can 

support competency-based learning and 

other forms of personalized instruction. 

Intergovernmental Review: This 

program is subject to Executive Order 

12372 and the regulations in 34 CFR 

part 79. One of the objectives of the 

Executive order is to foster an 

intergovernmental partnership and a 

strengthened federalism. The Executive 

order relies on processes developed by 

State and local governments for 

coordination and review of proposed 

Federal financial assistance. 

This document provides early 

notification of our specific plans and 

actions for this program. 

Accessible Format: Individuals with 

disabilities can obtain this document in 

an accessible format (e.g., braille, large 

print, audiotape, or compact disc) on 

request to the program contact person 

listed under FOR FURTHER INFORMATION

CONTACT. 

Electronic Access to This Document: 

The official version of this document is 

the document published in the Federal 

Register. Free Internet access to the 

official edition of the Federal Register 

and the Code of Federal Regulations is 

available via the Federal Digital System 

at: www.gpo.gov/fdsys. At this site you 

can view this document, as well as all 

other documents of this Department 

published in the Federal Register, in 

text or Adobe Portable Document 

Format (PDF). To use PDF you must 

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You may also access documents of the 

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Register by using the article search 

feature at: www.federalregister.gov. 

Specifically, through the advanced 

search feature at this site, you can limit 

your search to documents published by 

the Department. 

Dated: April 12, 2016. 

Ann Whalen, 

Senior Advisor to the Secretary Delegated 

the Duties of Assistant Secretary for 

Elementary and Secondary Education. 

[FR Doc. 2016–08726 Filed 4–15–16; 8:45 am] 

BILLING CODE 4000–01–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 131 

[EPA–HQ–OW–2016–0012; FRL–9944–70– 

OW] 

RIN 2040–AF60 

Aquatic Life Criteria for Copper and 

Cadmium in Oregon 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) proposes to establish 

federal Clean Water Act (CWA) aquatic 

life criteria for freshwaters under the 

state of Oregon’s jurisdiction, to protect 

aquatic life from the effects of exposure 

to harmful levels of copper and 

cadmium. In 2013, EPA determined that 

the freshwater acute cadmium criterion 

and freshwater acute and chronic 

copper criteria that Oregon adopted in 

2004 did not meet CWA requirements to 

protect aquatic life in the state. 

Therefore, EPA proposes to establish 

federal freshwater criteria for cadmium 

and copper that take into account the 

best available science, EPA policies, 

guidance and legal requirements, to 

protect aquatic life uses in Oregon. 

DATES: Comments must be received on 

or before June 2, 2016. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–HQ– 

OW–2016–0012, at http://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Once submitted, comments cannot be 

edited or removed from Regulations.gov. 

EPA may publish any comment received 

to its public docket. Do not submit 

electronically any information you 

consider to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Multimedia submissions (audio, video, 

etc.) must be accompanied by a written 

comment. The written comment is 

considered the official comment and 

should include discussion of all points 

you wish to make. EPA will generally 

not consider comments or comment 

contents located outside of the primary 

submission (i.e. on the web, cloud, or 

other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/

commenting-epa-dockets. 

EPA is offering two virtual public 

hearings so that interested parties may 

also provide oral comments on this 

proposed rule. The first hearing will be 

on Monday, May 16, 2016 from 4:00pm 

to 6:00pm Pacific Time. The second 

hearing will be on Tuesday, May 17, 

2016 from 9:00am to 11:00am Pacific 

Time. For more details on the public 

hearings and a link to register, please 

visit http://www.epa.gov/wqs-tech/

water-quality-standards-regulationsoregon. 

FOR FURTHER INFORMATION CONTACT: 

Erica Fleisig, Office of Water, Standards 

and Health Protection Division (4305T), 

Environmental Protection Agency, 1200 

Pennsylvania Avenue NW., Washington, 

DC 20460; telephone number: (202) 

566–1057; email address: fleisig.erica@

epa.gov. 

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. EPA’s Disapproval of Oregon’s 

Freshwater Copper and Cadmium 

Criteria 

C. General Recommended Approach for 

Deriving Aquatic Life Criteria 

III. Freshwater Cadmium Aquatic Life 

Criteria 

A. EPA’s National Recommended 

Cadmium Criteria 

B. Proposed Acute Cadmium Criterion for 

Oregon’s Freshwaters 

C. Implementation of Proposed Freshwater 

Acute Cadmium Criterion in Oregon 

IV. Freshwater Copper Aquatic Life Criteria 

A. EPA’s National Recommended Copper 

Criteria 

B. Proposed Acute and Chronic Copper 

Criteria for Oregon’s Freshwaters 

C. Implementation of Proposed Freshwater 

Acute and Chronic Copper Criteria in 

Oregon 

D. Ongoing State Efforts To Develop 

Copper Criteria for Oregon’s Freshwaters 

E. Incorporation by Reference 

V. Critical Low-Flows and Mixing Zones 

VI. Endangered Species Act 

VII. Under what conditions will federal 

standards be not promulgated or 

withdrawn? 

VIII. Alternative Regulatory Approaches and 

Implementation Mechanisms 

A. Designating Uses 

B. Site-Specific Criteria 

C. Variances 

D. Compliance Schedules 

IX. Economic Analysis 

A. Identifying Affected Entities 

B. Method for Estimating Costs 

C. Results 

X. Statutory and Executive Order Reviews 

A. Executive Order 12866 (Regulatory 

Planning and Review) and Executive 

Order 13563 (Improving Regulation and 

Regulatory Review) 

B. Paperwork Reduction Act 

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act 

E. Executive Order 13132 (Federalism) 

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22556 Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 

F. Executive Order 13175 (Consultation 

and Coordination With Indian Tribal 

Governments) 

G. Executive Order 13045 (Protection of 

Children From Environmental Health 

and Safety Risks) 

H. Executive Order 13211 (Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use) 

I. National Technology Transfer and 

Advancement Act of 1995 

J. Executive Order 12898 (Federal Actions 

To Address Environmental Justice in 

Minority Populations and Low-Income 

Populations) 

I. General Information 

Does this action apply to me? 

Copper and cadmium naturally occur 

at low levels in surface waters but, at 

higher concentrations, can be toxic to 

aquatic life. Anthropogenic activities 

such as coal combustion, mining, 

electroplating, iron and steel 

production, and use of pigments, 

fertilizers and pesticides, can increase 

levels of cadmium in the environment. 

Sources of elevated copper in the 

environment include mining, 

fabrication of paper, metal products and 

electronics, and discharges from 

wastewater treatment plants. 

Entities such as industries, 

stormwater management districts, or 

publicly owned treatment works 

(POTWs) that discharge pollutants to 

freshwaters of the United States under 

the state of Oregon’s jurisdiction could 

be indirectly affected by this 

rulemaking, because federal WQS 

promulgated by EPA would be 

applicable to CWA regulatory programs, 

such as National Pollutant Discharge 

Elimination System (NPDES) 

permitting. 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: 

Category Examples of potentially affected entities 

Industry ........................................... Industries discharging pollutants to freshwaters of the United States in Oregon. 

Municipalities ................................... Publicly owned treatment works or other facilities discharging pollutants to freshwaters of the United States 

in Oregon. 

Stormwater Management Districts .. Entities responsible for managing stormwater runoff in the state of Oregon. 

This table is not intended to be 

exhaustive, but rather provides a guide 

for readers regarding entities that could 

be indirectly affected by this action. 

Any parties or entities who depend 

upon or contribute to the water quality 

of 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 101(a)(2) establishes a 

national goal wherever attainable of 

‘‘water quality which provides for the 

protection and propagation of fish, 

shellfish, and wildlife and provides for 

recreation in and on the water . . . ’’ 

These are commonly referred to as the 

‘‘fishable/swimmable’’ goals of the 

CWA. 

CWA section 303(c) (33 U.S.C. 

1313(c)) directs states to adopt WQS for 

their waters subject to the CWA. CWA 

section 303(c)(2)(A) and EPA’s 

implementing regulations at 40 CFR part 

131 require, among other things, that a 

state’s WQS specify designated uses of 

the waters, and water quality criteria 

that protect those uses. EPA’s 

regulations at 40 CFR 131.11(a)(1) 

provide that ‘‘[s]uch criteria must be 

based on sound scientific rationale and 

must contain sufficient parameters or 

constituents to protect the designated 

use.’’ In addition, 40 CFR 131.10(b) 

provides that ‘‘[i]n designating uses of a 

water body and the appropriate criteria 

for those uses, the [s]tate shall take into 

consideration the water quality 

standards of downstream waters and 

shall ensure that its water quality 

standards provide for the attainment 

and maintenance of the water quality 

standards of downstream waters.’’ 

States are required to review 

applicable WQS at least once every 

three years and, if appropriate, revise or 

adopt new standards (CWA section 

303(c)(1)). Any new or revised WQS 

must be submitted to EPA for review 

and approval or disapproval (CWA 

section 303(c)(2)(A) and (c)(3)). If EPA 

determines that a WQS that a state 

submits to EPA for review does not meet 

the requirements of the CWA, EPA must 

notify the state of the changes necessary 

to meet CWA requirements (CWA 

section 303(c)(3)). CWA section 

303(c)(3) and (c)(4) further specify that 

if a state does not make those changes 

within 90 days of notification, EPA 

must promptly prepare and publish a 

revised or new WQS for the state. Under 

CWA section 303(c)(4)(B), the 

Administrator is authorized to 

determine, even in the absence of a state 

submission, that a new or revised 

standard is needed to meet CWA 

requirements. 

Under CWA section 304(a), EPA 

periodically publishes criteria 

recommendations for states to consider 

when adopting water quality criteria for 

particular pollutants to meet the CWA 

section 101(a)(2) goals. In establishing 

numeric criteria, states should adopt 

water quality criteria based on EPA’s 

CWA section 304(a) criteria, section 

304(a) criteria modified to reflect sitespecific conditions, or other 

scientifically defensible methods (40 

CFR 131.11(b)(1)). Ultimately, whatever 

methods are used, criteria must protect 

the designated use and be based on 

sound scientific rationale (40 CFR 

131.11(a)(1)). 

B. EPA’s Disapproval of Oregon’s 

Freshwater Copper and Cadmium 

Criteria 

On July 8, 2004, Oregon submitted 89 

revised aquatic life criteria for 25 toxic 

pollutants to EPA for review under 

CWA 303(c). Many of Oregon’s revised 

criteria were the same as EPA’s 

nationally recommended 304(a) aquatic 

life criteria at the time. A subsequent 

consent decree between EPA and 

Northwest Environmental Advocates 

established deadlines for EPA to 

complete its CWA 303(c) review of 

Oregon’s aquatic life criteria. Prior to 

taking a final action on the aquatic life 

criteria, 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 criteria, 

consistent with section 7 of the 

Endangered Species Act (ESA). EPA 

initiated this consultation on January 

14, 2008, by submitting a biological 

evaluation to the NMFS and USFWS, 

which contained an analysis of the 

potential effects of EPA’s proposed 

approval of Oregon’s criteria on 

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Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 22557 

1EPA initiated consultation on Oregon’s 

aluminum criteria based on its mistaken belief that 

Oregon’s criteria were entirely equivalent to EPA’s 

1988 304(a) recommended criteria. However, 

Oregon’s criteria specified that they applied ‘‘to 

waters with pH values less than 6.6 and hardness 

values less than 12 mg/L (as CaCO3)’’ whereas 

EPA’s 1988 304(a) recommended criteria ‘‘apply at 

pH values of 6.5–9.0.’’ EPA ultimately disapproved 

Oregon’s criteria because the state had not supplied 

a scientific rationale for the difference between 

Oregon’s statement of the conditions under which 

the criteria would be valid and EPA’s specified pH 

range for the criteria. Since EPA was disapproving 

the aluminum criteria, it sent a letter to the NMFS 

and USFWS identifying this change. The USFWS 

had already completed and transmitted its nonjeopardy opinion to EPA by that point, so it was too 

late for EPA to withdraw the consultation request 

for aluminum. However, in the letter to the NMFS, 

EPA withdrew its request for consultation on 

Oregon’s acute and chronic aluminum criteria. 

2The NMFS acknowledged EPA’s request to 

withdraw the aluminum criteria from consultation; 

however, they did not have time to modify the 

biological opinion to exclude acute and chronic 

aluminum from the document. 

3The NMFS determined that the criterion Oregon 

adopted to protect aquatic life from adverse chronic 

effects from cadmium would not jeopardize the 

continued existence of endangered species; EPA 

approved Oregon’s chronic cadmium criterion in 

January 2013. 

4USEPA. 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. 

http://www.epa.gov/sites/production/files/2015-08/

documents/guidelines_for_deriving_nnwqc_for_the_

protectin_of_aquatic_organisms_and_their_

uses.pdf. 

5 In EPA’s 2001 304(a) recommendation for 

cadmium and the 2007 304(a) recommendation for 

copper, EPA specified that the acute cadmium and 

copper criteria (CMCs) had 24-hour (rather than 

one-hour) durations. Subsequently, in the 2016 

304(a) update for cadmium, EPA revised the 

cadmium CMC duration to one-hour to reflect the 

acute criteria duration recommended in the 1985 

Guidelines. EPA proposes that the duration for both 

copper and cadmium CMCs in this rule be onehour, to be consistent with the updated 304(a) 

recommendation for cadmium and with EPA’s 1985 

Guidelines. As articulated on page 35 of USEPA’s 

1991 Technical Support Document for Water 

Quality-based Toxics Control, March, 1991 (EPA/

505/2–90–001), a one-hour averaging period is 

expected to be fully protective for the fastest-acting 

toxicants, and even more protective for sloweracting toxicants. 

6See USEPA, 1985. Pages. 5–7. 

threatened and endangered species in 

Oregon.1

On July 31, 2012, the USFWS 

provided its biological opinion to EPA. 

The biological opinion found that EPA’s 

proposed approval of Oregon’s aquatic 

life criteria would not jeopardize the 

continued existence of endangered 

species for which USFWS was 

responsible. However, on August 14, 

2012, the 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 the NMFS was 

responsible. These seven criteria were 

the freshwater criteria Oregon adopted 

to protect aquatic life from adverse 

acute and chronic effects from 

ammonia, copper, and aluminum,2 as 

well as the criterion to prevent adverse 

acute effects from cadmium. The NMFS 

biological opinion contained Reasonable 

and Prudent Alternatives (RPAs) for 

each of the four pollutants that would 

avoid the likelihood of jeopardy to the 

species. For acute ammonia and 

cadmium, and acute and chronic 

aluminum, the RPA specified a process 

for deriving revised freshwater criteria. 

For the chronic ammonia criterion, the 

RPA specified that Oregon’s previously 

applicable chronic ammonia criterion, 

which was based on EPA’s 1985 304(a) 

recommendation, should remain in 

place. The NMFS RPA for acute and 

chronic copper criteria was to establish 

‘‘a new acute criterion of 2.3 mg/L for 

freshwater copper using EPA’s 2007 

[Biotic Ligand Model (BLM)]-based 

aquatic life criteria’’ and ‘‘a new chronic 

criterion of 1.45 mg/L for freshwater 

copper using EPA’s 2007 BLM-based 

aquatic life criteria.’’ On January 19, 

2016 the NMFS sent EPA a letter 

clarifying that ‘‘. . . use of EPA’s 2007 

copper BLM to derive copper criteria 

that are specific to individual locations 

or ecoregions is appropriate under the 

RPA, provided that the state of Oregon 

has the appropriate data to input into 

the BLM and appropriate procedures to 

use the BLM.’’ 

On January 31, 2013, EPA 

disapproved several of Oregon’s revised 

aquatic life criteria under CWA 303(c), 

including the acute cadmium freshwater 

criterion, and the acute and chronic 

freshwater ammonia, copper, and 

aluminum criteria that the NMFS 

concluded would jeopardize 

endangered species in Oregon.3 Oregon 

made changes to its freshwater ammonia 

criteria in response to EPA’s 2013 

disapproval and submitted revised 

freshwater ammonia criteria to EPA on 

January 23, 2015. EPA evaluated the 

revised freshwater ammonia criteria’s 

consistency with the RPA for ammonia 

contained in the 2012 NMFS biological 

opinion, concluded that the revised 

criteria would protect endangered 

species in Oregon, and approved the 

revised criteria on August 4, 2015. 

Although Oregon has been working 

closely with EPA to derive protective 

freshwater copper criteria that the state 

would adopt in a future rulemaking, the 

state has not yet addressed EPA’s 2013 

disapproval of its freshwater criteria for 

cadmium, copper, and aluminum. EPA 

is proposing the freshwater acute 

cadmium, and acute and chronic copper 

criteria in this rule in accordance with 

CWA section 303(c)(3) and (c)(4) 

requirements. EPA intends to propose 

freshwater acute and chronic criteria for 

aluminum in Oregon in a separate 

rulemaking at a later date following 

completion of updates to EPA’s CWA 

section 304(a) recommended criteria for 

aluminum. 

C. General Recommended Approach for 

Deriving Aquatic Life Criteria 

Under the Agency’s CWA section 

304(a) authority, EPA develops 

methodologies and specific criteria to 

protect aquatic life and human health. 

These methodologies and criteria are 

subject to public as well as scientific 

expert review before EPA releases them 

as formal agency recommendations for 

states to consider when developing and 

adopting water quality criteria. To 

derive criteria for the protection of 

aquatic life, EPA follows its Guidelines 

for Deriving Numerical National Water 

Quality Criteria for the Protection of 

Aquatic Organisms and Their Uses 

(referred to as the ‘‘1985 Guidelines’’).4

These 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. 

Numeric criteria derived using EPA’s 

1985 Guidelines are expressed as shortterm (acute) and long-term (chronic) 

values. The combination of a criteria 

maximum concentration (CMC), a onehour average value, and a criteria 

continuous concentration (CCC), a fourday average value, protects aquatic life 

from acute and chronic toxicity, 

respectively.5 Neither value is to be 

exceeded more than once in three years. 

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. EPA 

based its once every three years 

exceedance frequency recommendation 

on the ability of aquatic ecosystems to 

recover from the exceedances (when the 

average concentration over the duration 

of the averaging period is above the CCC 

or the CMC).6

Since fresh and salt waters have 

different chemical compositions and 

different species assemblages, it is 

necessary to derive separate acute and 

chronic criteria for fresh and salt waters. 

Additionally, criteria may be based on 

certain water characteristics (e.g., pH, 

temperature, hardness, dissolved 

organic carbon (DOC), etc.), since water 

chemistry can influence a pollutant’s 

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22558 Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 

7Water Quality Standards; Establishment of 

Numeric Criteria for Priority Toxic Pollutants; 

States’ Compliance—Revision of Metals Criteria, 

May 4, 1995, 60 FR 22229. 

8See USEPA, 1985. 

9The 2001 304(a) national recommended 

freshwater cadmium criteria were the same criteria 

that Oregon adopted and submitted to EPA in 2004. 

USEPA. 2001. 2001 Update of Ambient Water 

Quality Criteria for Cadmium. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC 

EPA–822–R–01–001. http://water.epa.gov/scitech/

swguidance/standards/criteria/current/

index.cfm#altable. 

10See http://www.epa.gov/wqc/aquatic-lifecriteria-cadmium. 

11Oregon currently uses a default hardness 

concentration of 25 mg/L if no hardness data are 

available to calculate hardness-dependent metals 

criteria. See Oregon Department of Environmental 

Quality. 2014. Methodology for Oregon’s 2012 

Water Quality Report and List of Water Quality 

Limited Waters (Pursuant to Clean Water Act 

Sections 303(d) and 305(b) and OAR 340–041– 

0046). Pages 76–77. 

12EPA used 10th percentile calcium and 

magnesium data from USEPA’s Draft Technical 

Support Document: Recommended Estimates for 

Missing Water Quality Parameters for Application 

in EPA’s Biotic Ligand Model, February 16, 2016 

(EPA 820–R–15–106), along with the following 

equation to relate calcium and magnesium to 

hardness: mg/L CaCO3 = 2.5*(calcium 

concentration in mg/L as Ca2+) + 4.1*(magnesium 

concentration in mg/L as Mg2+). 

For a map of Level III ecoregions in the 

continental United States, see http://

archive.epa.gov/wed/ecoregions/web/html/level_iii_

iv-2.html#LevelIII. 

bioavailability and toxicity. For metals 

in particular, EPA recommends 

expressing the criteria as functions of 

chemical constituents of the water, 

since those constituents can form 

complexes with metals and render the 

metals biologically unavailable, or 

compete with metals for binding sites 

on aquatic organisms. Additionally, in 

1995, EPA recommended that criteria 

for metals be expressed as dissolved 

(rather than total) metal concentrations, 

since the concentration of dissolved 

metal better approximates the toxic 

fraction.7

The 1985 Guidelines specify that it is 

necessary to have toxicity test data from 

a minimum of eight families of aquatic 

organisms to derive criteria. These 

families 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, states may develop 

site-specific criteria using species 

residing at the site if they maintain 

similar broad taxonomic representation. 

EPA derives acute criteria from 48- to 

96-hour tests of lethality or 

immobilization. EPA derives chronic 

criteria from longer term (often longer 

than 28-day) tests that measure survival, 

growth, or reproduction. If sufficient 

chronic toxicity data are not available, 

chronic criteria are set by determining a 

ratio of acutely toxic to chronically toxic 

concentrations. Where appropriate, EPA 

recommends that criteria are lowered to 

protect commercially or recreationally 

important species. 

For more detailed information on how 

EPA derives protective aquatic life 

criteria, see the 1985 Guidelines.8

III. Freshwater Cadmium Aquatic Life 

Criteria 

A. EPA’s National Recommended 

Cadmium Criteria 

Water hardness (determined by the 

presence of calcium and magnesium 

ions, and expressed as calcium 

carbonate, CaCO3) affects the toxicity of 

cadmium, as calcium and magnesium 

ions compete with cadmium for binding 

sites on aquatic organisms’ gills. 

Organisms show more sensitivity to 

cadmium in lower hardness (soft) water 

than in hard water. EPA therefore 

expresses the national 304(a) 

recommended acute and chronic 

cadmium criteria as functions of water 

hardness. 

EPA previously published final 304(a) 

recommended aquatic life criteria for 

cadmium in 2001.9 In recent years, EPA 

embarked on an update to the science 

underlying the 2001 national cadmium 

criteria recommendations. This work 

included a literature search of 

toxicological databases, evaluation of 

those data, recalculation of the criteria 

based on those data updates, and 

revision of supporting documentation. 

In 2015, EPA completed an external 

peer review of the draft updated 

cadmium criteria and revised them 

accordingly. EPA then published the 

draft criteria for public comment in the 

Federal Register, and solicited 

comments for 60 days (December 1, 

2015, 80 FR 75097). EPA revised the 

criteria to respond to the public 

comments, and expects the final 

national updated 304(a) recommended 

cadmium criteria to be published in the 

Federal Register in April 2016.10

B. Proposed Acute Cadmium Criterion 

for Oregon’s Freshwaters 

To protect aquatic life in Oregon’s 

freshwaters from acute toxic effects from 

cadmium, EPA proposes the one-hour 

average CMC not exceed e(0.9789 ×

ln(hardness)¥3.866) × CF (mg/L, dissolved) 

more than once every three years. ‘‘CF’’ 

refers to the conversion factor and is 

used to convert the total recoverable 

concentration to a dissolved 

concentration, consistent with EPA’s 

policy on criteria for metals. The 

equation for the acute cadmium CF is 

CF = 1.136672¥[(ln hardness) × 

(0.041838)]. This is the same freshwater 

acute cadmium criterion (and associated 

CF) as in EPA’s final 2016 national 

updated 304(a) recommended cadmium 

criteria. The (ln hardness) term in both 

the CMC equation and the CF equation 

is the natural logarithm of the ambient 

water hardness in mg/L (CaCO3). 

Where site-specific hardness data are 

unavailable, EPA proposes to use a 

default hardness concentration of 25 

mg/L (as CaCO3), which equates to a 

one-hour average dissolved cadmium 

concentration of 0.49 mg/L.11 As with 

other metals criteria in Oregon that are 

expressed as a function of hardness, the 

acute cadmium criterion equation 

requires ambient hardness data that 

represent the entire site to which the 

criterion will apply to calculate an acute 

cadmium criterion for a site. EPA 

strongly recommends that Oregon 

collect sufficiently representative 

ambient hardness data to determine the 

appropriate acute cadmium criterion for 

a site. However, EPA recognizes that, in 

certain situations, there will not be 

sufficiently representative ambient 

hardness data to adequately characterize 

the site; thus, EPA is proposing a default 

hardness concentration to provide 

clarity to NPDES permit writers and 

water body assessors on what acute 

cadmium criterion applies at the site. 

EPA evaluated the protectiveness of 

using a default hardness of 25 mg/L by 

calculating the 10th percentile of 

existing hardness concentrations in 

Oregon’s waters, using U.S. Geological 

Survey (USGS) data on calcium and 

magnesium ion levels in waters within 

each of the nine Level III ecoregions in 

Oregon.12 EPA selected the 10th 

percentile as a statistic that is both 

protective and can be reliably 

determined from small sample sizes. 

The USGS dataset that EPA evaluated 

indicates that the lowest 10th percentile 

ecoregional hardness in Oregon is 28 

mg/L, suggesting that a default hardness 

concentration of 25 mg/L would be 

protective of the majority of Oregon’s 

waters. However, certain water bodies 

in Oregon, such as relatively unimpacted headwaters, could have 

hardness concentrations below 25 mg/L, 

and Oregon should prioritize collecting 

ambient hardness data in those waters 

to ensure the resulting acute cadmium 

criteria are protective of aquatic life. 

EPA’s proposal to use a default 

hardness of 25 mg/L in the absence of 

sufficiently representative ambient 

hardness data should not be confused 

with use of a low-end hardness floor 

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13USEPA. 2002. National Recommended Water 

Quality Criteria: 2002. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC 

EPA–822–R–02–047. 

14USEPA. 2013. EPA Clean Water Act 303(c) 

Determinations On Oregon’s New and Revised 

Aquatic Life Toxic Criteria Submitted on July 8, 

2004, and as Amended by Oregon’s April 23, 2007 

and July 21, 2011 Submissions. Page 46. 

15USEPA. 1994. Interim Guidance on 

Determination and Use of Water-Effect Ratios for 

Metals. U.S. Environmental Protection Agency, 

Office of Water, Washington, DC EPA–823–B–94– 

001. February 1994. 

16USEPA. 2010. NPDES Permit Writers’ Manual. 

U.S. Environmental Protection Agency, Office of 

Water, Washington, DC EPA–833–K–10–001. 

September 2010. 

17USEPA. 2007. Aquatic Life Ambient Freshwater 

Quality Criteria—Copper. U.S. Environmental 

Protection Agency, Office of Water, Washington, DC 

EPA–822–R–07–001. http://water.epa.gov/scitech/

swguidance/standards/criteria/aqlife/copper/

upload/2009_04_27_criteria_copper_2007_criteriafull.pdf. 

18USEPA. 2007. Copper Aquatic Life Criteria: 

Supplementary Training Materials. U.S. 

Environmental Protection Agency, Office of Water, 

Washington, DC http://water.epa.gov/scitech/

swguidance/standards/criteria/aqlife/copper/faq_

index.cfm. See ‘‘Data Requirements.’’ 

even when ambient data are available 

measuring hardness below 25 mg/L. 

Consistent with EPA guidance, a site’s 

actual ambient water hardness should 

be used to calculate the criterion when 

sufficiently representative hardness data 

are available, even if the hardness is 

below 25 mg/L.13

In describing potential remedies to 

address EPA’s January 2013 

disapproval, EPA noted that ‘‘new 

scientific data on the toxicity of 

cadmium [are] now available and would 

need to be reviewed regarding their 

quality and relevance prior to being 

considered in developing an updated 

recommendation for a specific numeric 

criterion protective of Oregon aquatic 

life.’’ 14 EPA’s 2016 section 304(a) 

recommended cadmium criteria update 

represents a thorough review and 

incorporation of the latest scientific data 

on cadmium toxicity to aquatic life. The 

updated 304(a) recommended 

freshwater acute cadmium criterion, 

which EPA is proposing to apply in 

Oregon, now incorporates a more robust 

dataset on cadmium’s acutely toxic 

effects, and was lowered to protect 

commercially and recreationally 

important salmonids, consistent with 

EPA’s 1985 Guidelines. Additionally, 

EPA’s proposal of a default hardness 

value as part of the criterion for Oregon 

will ensure that protective cadmium 

criteria can be easily derived for all 

freshwaters in the state. Therefore, EPA 

proposes that the 2016 section 304(a) 

recommended acute cadmium criterion, 

in combination with a protective 

hardness default that will apply in the 

absence of sufficiently representative 

ambient hardness data, will protect 

aquatic life in Oregon. 

C. Implementation of Proposed 

Freshwater Acute Cadmium Criterion in 

Oregon 

When calculating a hardness-based 

criterion value, Oregon should consider 

the following when defining a site to 

which the acute cadmium criterion 

applies: (1) Metals are generally 

persistent, so calculating the criterion 

using hardness values from a small site 

at or near the discharge point could 

result in a criterion that is not protective 

of areas that are outside the defined site, 

and (2) 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.15

Additionally, pursuant to 40 CFR 

131.10(b), Oregon must consider 

downstream WQS when calculating a 

protective criterion concentration in 

upstream waters. 

When setting Water Quality-Based 

Effluent Limitations (WQBELs), Oregon 

should determine the water body’s 

ambient hardness level under critical 

conditions (i.e., low hardness) when 

cadmium toxicity is expected to be 

higher, such that the resulting cadmium 

criterion is protective of the entire site 

at critical and less than critical 

conditions. EPA’s NPDES Permit 

Writers’ Manual describes the 

importance of determining 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.16 Because 

organisms are more sensitive to 

cadmium when corresponding hardness 

concentrations are low, Oregon should 

ensure that sufficiently representative 

ambient hardness data are collected to 

have confidence that critical conditions 

in the water body are being adequately 

captured. 

Substantial changes in a site’s 

ambient hardness will likely affect the 

resulting acute cadmium criterion at 

that site. Therefore, EPA recommends 

that Oregon periodically revisit each 

water body’s acute cadmium criterion 

and re-run the equation when changes 

in water hardness are evident or 

suspected at a site, and also as 

additional monitoring data become 

available. 

IV. Freshwater Copper Aquatic Life 

Criteria 

A. EPA’s National Recommended 

Copper Criteria 

In 2007, EPA issued revised section 

304(a) national recommended 

freshwater aquatic life criteria for 

copper that represent the best available 

science and understanding of the 

interaction between water chemistry 

and copper toxicity.17 These criteria 

recommendations incorporate use of a 

Biotic Ligand Model (BLM), which is a 

metal bioavailability model that uses 

receiving water body characteristics to 

develop water quality criteria on a sitespecific basis. The BLM requires 

ambient data on ten water body-specific 

characteristics to calculate a freshwater 

copper criterion (temperature, pH, 

dissolved organic carbon (DOC), 

calcium, magnesium, sodium, 

potassium, sulfate, chloride, and 

alkalinity). 

Along with the criteria 

recommendations, EPA released 

supplementary materials related to 

using the BLM on a site-specific basis to 

derive criteria. Training materials that 

EPA released in 2007 discussed 

considerations such as collecting 

sufficiently representative data to 

account for a site’s spatial and temporal 

variability, properly defining the site to 

which the BLM-derived criterion 

applies, reconciling multiple model 

runs, and estimating input parameters 

when site-specific data are lacking.18 To 

address situations where site-specific 

data are not available for some of the 

BLM’s ten input variables, EPA 

published for public comment the Draft 

Technical Support Document: 

Recommended Estimates for Missing 

Water Quality Parameters for 

Application in EPA’s Biotic Ligand 

Model (EPA 820–R–15–106) on 

February 16, 2016 (81 FR 7784). 

B. Proposed Acute and Chronic Copper 

Criteria for Oregon’s Freshwaters 

To protect aquatic life in Oregon’s 

freshwaters, EPA proposes the CMC and 

CCC based on the 2007 304(a) 

recommended copper BLM. EPA 

proposes to express the CMC as a onehour average dissolved copper 

concentration (in mg/L) and the CCC as 

a four-day average dissolved copper 

concentration (in mg/L), and that the 

CMC and CCC are not to be exceeded 

more than once every three years. 

As with hardness data used to 

determine the acute cadmium criterion 

discussed earlier, EPA recommends that 

Oregon collect ambient data to 

determine protective copper criteria by 

site. In the absence of sufficiently 

representative ambient data to run the 

BLM, EPA proposes default input values 

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19EPA is not proposing default input values for 

the other two BLM inputs, pH and temperature, 

because pH and temperature are highly variable and 

routinely monitored. EPA anticipates that 

sufficiently representative site-specific data will be 

available for these parameters. Even though EPA is 

proposing default values for DOC, EPA 

recommends that Oregon collect site-specific 

measurements of DOC if possible, because copper 

toxicity and BLM predictions are highly sensitive 

to DOC concentrations. 

20See USEPA, 2016. EPA’s proposed default 

inputs are from Tables 4, 8, 9, 10 and 20. 

for DOC, calcium, magnesium, sodium, 

potassium, sulfate, chloride, and 

alkalinity that are based on the 10th 

percentile of existing concentrations of 

these variables in waters within each of 

Oregon’s Level III ecoregions.19 If 

information exists to characterize a 

water body’s stream order (a measure of 

the relative size of a stream), EPA 

proposes to instead use the 10th 

percentile concentrations by stream 

order within each of Oregon’s Level III 

ecoregions. These defaults (by ecoregion 

and by stream order within each 

ecoregion) are set forth in Tables 1 and 

2 below and are described further in 

EPA’s Draft Technical Support 

Document: Recommended Estimates for 

Missing Water Quality Parameters for 

Application in EPA’s Biotic Ligand 

Model which can be found in the record 

for this rulemaking.20 Because EPA is 

proposing default input parameters, 

protective copper criteria can be easily 

derived for assessment and permitting 

purposes (even in the absence of 

ambient data). EPA solicits comments 

on the Agency’s proposal to use the 10th 

percentile of existing concentrations to 

derive default input parameters. EPA 

also solicits comments on using default 

input parameters based on a different 

percentile, such as the 5th or 25th (or 

another percentile within that range). 

Calculations of default input parameters 

at the 5th and 25th percentiles can also 

be found in the record for this 

rulemaking (see Fifth and Twenty-fifth 

Percentile Estimates for Copper BLM 

Input Parameters by Oregon Level III 

Ecoregion). 

Finally, EPA proposes that in order to 

calculate final acute and chronic copper 

criteria, Oregon use a value not to 

exceed the 10th percentile of individual 

BLM outputs for the site. While the 10th 

percentile should be protective in a 

majority of cases, certain circumstances 

may warrant use of a more stringent 

BLM output. When 10 or fewer data 

points are available for a given site, EPA 

proposes that Oregon use the lowest 

individual acute and chronic BLM 

outputs as the final acute and chronic 

criteria. EPA solicits comment on this 

approach, as well as alternative 

percentiles or approaches to reconciling 

individual copper BLM outputs into 

final acute and chronic copper criteria 

values. 

EPA’s proposed acute and chronic 

copper criteria for Oregon’s freshwaters 

are as follows: 

Acute (CMC) and chronic (CCC) freshwater 

copper criteria shall be developed using 

EPA’s 2007 Aquatic Life Ambient Freshwater 

Quality Criteria—Copper (EPA–822–R–07– 

001), which incorporates use of the copper 

biotic ligand model (BLM). 

Where sufficiently representative ambient 

data for DOC, calcium, magnesium, sodium, 

potassium, sulfate, chloride, or alkalinity are 

not available, the state shall use the 10th 

percentile estimated values from Table 1 

based on the applicable ecoregion (or Table 

2, based on the applicable ecoregion and 

stream order). 

The final copper criteria shall be calculated 

as no greater than the 10th percentile of the 

distribution of individual BLM outputs at a 

site. If 10 or fewer BLM outputs are available 

for a given site, the lowest individual acute 

and chronic BLM output values shall be used 

as the final acute and chronic copper criteria 

for that site. 

TABLE 1—BLM DEFAULT INPUTS FOR EACH LEVEL III ECOREGION IN OREGON

Level III Ecoregion Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

1 Coast Range .......................................................................... 8.4 3.2 4.1 0.64 33 3.2 4.8 0.7 

3 Willamette Valley ................................................................... 8.2 2.9 4.4 0.90 30 4.7 3.8 0.4 

4 Cascades ............................................................................... 6.6 2.9 3.5 0.74 35 2.2 3.2 0.3 

9 Eastern Cascades Slopes and Foothills ............................... 8.2 3.8 6.0 1.0 44 3.2 5.0 0.5 

10 Columbia Plateau ................................................................... 15 5.2 9.3 1.8 40 3.3 10 1.0 

11 Blue Mountains ...................................................................... 11 3.9 7.7 1.4 49 3.3 7.1 0.8 

12 Snake River Plain .................................................................. 33 10 13 2.3 109 10 22 1.2 

78 Klamath Mountains ................................................................ 8.7 4.6 4.0 0.66 44 2.1 3.5 0.6 

80 Northern Basin and Range .................................................... 26 8.2 20 2.7 89 15 24 1.0 

TABLE 2—BLM DEFAULT INPUTS FOR EACH STREAM ORDER WITHIN EACH LEVEL III ECOREGION IN OREGON

Level III Ecoregion Stream 

order 

Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

1 Coast Range ....................................................... SO 1–3 6.0 0.8 1.3 0.1 44 0.6 1.1 0.7 

SO 4–6 3.6 1.0 2.0 0.2 15 1.6 2.2 0.7 

SO 7–9 12 3.4 4.3 0.8 56 2.3 6.3 0.7 

3 Willamette Valley ................................................. SO 1–3 9.9 3.8 5.6 1.5 ................ 2.3 1.5 0.4 

SO 4–6 7.1 2.5 4.3 0.8 29 4.6 2.8 0.4 

SO 7–9 5.0 1.6 3.4 0.6 20 2.7 2.3 0.4 

4 Cascades ............................................................ SO 1–3 1.0 0.2 1.8 0.2 ................ 0.5 0.2 0.3 

SO 4–6 3.5 1.0 2.8 0.4 16 0.8 0.8 0.3 

SO 7–9 13 3.6 3.7 0.9 52 1.7 6.9 0.3 

9 Eastern Cascades Slopes and Foothills ............. SO 1–3 4.4 0.9 2.3 0.4 35 0.2 0.2 0.5 

SO 4–6 5.5 0.8 2.4 0.5 22 0.9 2.2 0.5 

SO 7–9 ................ .................... ................ .................. ................ ................ ................ 0.5

10 Columbia Plateau ................................................ SO 1–3 24.0 9.4 10.2 1.4 127 4.6 11 1.0 

SO 4–6 8.6 3.2 4.0 0.9 33 1.4 3.1 1.0 

SO 7–9 5.7 1.5 2.0 0.7 16 0.8 4.2 1.0 

11 Blue Mountains .................................................... SO 1–3 8.6 3.2 ................ .................. 169 ................ ................ 0.8 

SO 4–6 3.7 0.8 1.6 0.7 16 0.3 0.7 0.8 

SO 7–9 8.5 1.5 3.3 0.7 32 0.8 5.0 0.8 

12 Snake River Plain ................................................ SO 1–3 13 2.0 6.1 0.8 35 1.4 3.7 1.2 

SO 4–6 13 2.5 4.9 1.2 40 2.2 3.8 1.2 

SO 7–9 37 10 13 2.5 122 11 30 1.2 

78 Klamath Mountains .............................................. SO 1–3 ................ .................... ................ .................. ................ 2.1 ................ 0.6 

SO 4–6 7.9 3.2 4.0 0.6 36 2.1 2.4 0.6 

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21USEPA. 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. 

22USEPA. 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. 

TABLE 2—BLM DEFAULT INPUTS FOR EACH STREAM ORDER WITHIN EACH LEVEL III ECOREGION IN OREGON—Continued 

Level III Ecoregion Stream 

order 

Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

SO 7–9 ................ .................... ................ .................. ................ ................ ................ 0.6

80 Northern Basin and Range .................................. SO 1–3 6.3 1.1 4.3 2.2 24 0.2 2.5 1.0 

SO 4–6 15 5.7 4.1 0.8 54 2.0 9.3 1.0 

SO 7–9 8.9 2.4 7.7 2.1 ................ 2.1 5.1 1.0 

EPA’s 2007 copper BLM represents 

the latest scientific knowledge on 

copper speciation and bioavailability. In 

describing potential remedies to address 

EPA’s January 2013 disapproval, EPA 

noted that Oregon could use the 2007 

copper BLM. The model provides 

predictable and repeatable outcomes, 

and EPA is proposing protective default 

inputs to use in the absence of sitespecific data. EPA proposes that the 

combination of the 2007 copper BLM 

and default inputs will protect aquatic 

life in Oregon. 

C. Implementation of Proposed 

Freshwater Acute and Chronic Copper 

Criteria in Oregon 

EPA’s proposed copper criteria for 

Oregon will be the first BLM-based 

criteria in Oregon and, therefore, the 

state does not have associated 

implementation methods. EPA strongly 

recommends that Oregon develop such 

methods, and give similar consideration 

to site selection, characterization of 

critical conditions, and data 

representativeness, as discussed for 

cadmium earlier in this proposed rule. 

Aquatic organisms are more sensitive to 

copper when corresponding DOC and 

pH levels in the water are low, so 

Oregon should ensure that sufficiently 

representative data are collected for the 

BLM’s input parameters to have 

confidence that critical conditions are 

adequately characterized. 

When Oregon derives copper criteria 

using the BLM, to promote transparency 

and ensure predictable and repeatable 

outcomes, EPA recommends that the 

state make each criterion and the 

geographic extent of the site to which 

the criterion applies publicly available 

on the state’s Web site along with 

information such as: 

1. The number of sampling events 

used to derive the criterion; 

2. Whether the criterion relied on sitespecific data, estimated data, or a 

combination of both; and 

3. The date when the criterion was 

developed. 

Finally, as discussed earlier with 

respect to ambient hardness levels, 

substantial changes in a site’s water 

chemistry will likely affect any resulting 

copper criterion at that site. In addition, 

with regular monitoring and a robust, 

site-specific dataset, criteria can be 

developed that more accurately reflect 

site conditions and copper 

bioavailability than criteria set using 

default values or limited data sets. 

Therefore, EPA recommends that 

Oregon periodically revisit its copper 

criteria and re-run the BLM when 

changes in water chemistry are evident 

or suspected at a site, and also as 

additional monitoring data become 

available. 

D. Ongoing State Efforts To Develop 

Copper Criteria for Oregon’s 

Freshwaters 

EPA’s proposed methodology for 

deriving protective acute and chronic 

copper criteria described in the 

preceding paragraphs is not necessarily 

the only scientifically defensible and 

protective approach, and consistent 

with 40 CFR 131.11(b)(1)(iii), Oregon 

has the option to establish criteria based 

on other scientifically defensible 

methods. In 2015, the Oregon 

Department of Environmental Quality 

(DEQ) conducted an analysis of the 

copper BLM in preparation for adopting 

revised copper criteria to address EPA’s 

2013 disapproval. DEQ has spent 

significant time and resources collecting 

BLM input parameters at 138 locations 

across the state, as well as evaluating 

various methods to develop defaults 

that can be used in the absence of 

sufficiently representative ambient data. 

To date, DEQ has generally modeled its 

approach after the methodology 

presented in EPA’s Draft Technical 

Support Document: Recommended 

Estimates for Missing Water Quality 

Parameters for Application in EPA’s 

Biotic Ligand Model (EPA 820–R–15– 

106), but is considering different data 

sources and alternative geographic 

groupings of water bodies. EPA is 

working closely with DEQ, and will 

continue to provide input on the state’s 

copper criteria development efforts. 

E. Incorporation by Reference 

EPA is proposing that the final EPA 

rule regulatory text will incorporate one 

EPA document by reference. In 

accordance with the requirements of 1 

CFR 51.5, EPA is proposing to 

incorporate by reference EPA’s 2007 

Aquatic Life Ambient Freshwater 

Quality Criteria—Copper (EPA–822–R– 

07–001), discussed in section IV.A. of 

this preamble. EPA has made, and will 

continue to make, this document 

generally available electronically 

through www.regulations.gov and/or in 

hard copy at the appropriate EPA office 

(see the ADDRESSES section of this 

preamble for more information). 

V. Critical Low-Flows and Mixing 

Zones 

To ensure that the proposed criteria 

are applied appropriately to protect 

Oregon’s aquatic life uses, EPA is 

proposing critical low-flow values for 

Oregon to use in 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. Low flows can 

exacerbate the effects of effluent 

discharges because, 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 

when low flows occur.21

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 EPA.22 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 

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23See USEPA, 2014. 

24See USEPA, 1991. 

25Highest 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 § 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)). 

specific duration and frequency 

associated with the criterion. For the 

acute cadmium and acute and chronic 

copper criteria, EPA proposes the 

following critical low-flow values: 

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 sevenconsecutive-day average flow event 

expected to occur once every ten years, 

on average. Using the biologically based 

method, 1B3 represents the lowest oneday 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.23

The criteria in this proposed rule, 

once finalized, would apply 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 CCC would apply at the 

defined boundary of the chronic mixing 

zone and the CMC would apply at the 

defined boundary of the acute mixing 

zone).24

VI. Endangered Species Act 

As noted earlier in this proposed rule, 

the NMFS 2012 biological opinion 

concluded that the acute cadmium and 

acute and chronic copper criteria that 

Oregon adopted in 2004 would 

jeopardize the continued existence of 

endangered species in Oregon. The 

opinion also contained RPAs for 

cadmium and copper that would avoid 

the likelihood of jeopardy to endangered 

species in Oregon. EPA will continue to 

work closely with the NMFS to ensure 

that the acute cadmium criterion that 

EPA ultimately finalizes is protective of 

federally listed species in Oregon. For 

copper, the NMFS further clarified in 

January 2016 that adoption of EPA’s 

2007 copper BLM, which EPA is 

proposing in this rule, would be 

consistent with the 2012 RPA. 

VII. Under what conditions will 

Federal standards be not promulgated 

or withdrawn? 

Under the CWA, Congress gave states 

primary responsibility for developing 

and adopting WQS for their waters 

(CWA section 303(a)–(c)). Although EPA 

is proposing cadmium and copper 

aquatic life criteria for Oregon’s 

freshwaters to remedy EPA’s 2013 

disapproval, Oregon continues to have 

the option to adopt and submit to EPA 

acute cadmium and acute and chronic 

copper criteria for the state’s freshwaters 

consistent with CWA section 303(c) and 

EPA’s implementing regulations at 40 

CFR part 131. EPA encourages Oregon 

to expeditiously adopt protective 

aquatic life criteria. Consistent with 

CWA section 303(c)(4), if Oregon adopts 

and submits cadmium and/or copper 

aquatic life criteria, and EPA approves 

such criteria before finalizing this 

proposed rule, EPA would not proceed 

with the promulgation for those waters 

and/or pollutants for which EPA 

approves Oregon’s criteria. 

If EPA finalizes this proposed rule, 

and Oregon subsequently adopts and 

submits cadmium and/or copper aquatic 

life criteria, EPA proposes that once 

EPA approves Oregon’s WQS, the EPAapproved criteria in Oregon’s WQS 

would become the applicable criteria for 

CWA purposes and EPA’s promulgated 

criteria would no longer be applicable 

criteria. EPA would undertake a 

rulemaking to withdraw the federal 

criteria for cadmium and/or copper, but 

that process would not delay Oregon’s 

approved criteria from becoming the 

sole applicable criteria for CWA 

purposes. 

VIII. Alternative Regulatory 

Approaches and Implementation 

Mechanisms 

Oregon will have considerable 

discretion to implement these aquatic 

life criteria, once finalized, through 

various water quality control programs. 

Among other things, EPA’s regulations: 

(1) Specify how states and authorized 

tribes establish, modify or remove 

designated uses, (2) specify the 

requirements for establishing criteria to 

protect designated uses, including 

criteria modified to reflect site-specific 

conditions, (3) authorize states and 

authorized tribes to adopt WQS 

variances to provide time to achieve the 

applicable WQS, and (4) allow states 

and authorized tribes to include 

compliance schedules in NPDES 

permits. Each of these approaches are 

discussed in more detail below. 

A. Designating Uses 

EPA’s proposed cadmium and copper 

criteria apply to freshwaters 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 regulations at 40 

CFR 131.10 provide information on 

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,25 and 

EPA finds that removal to be consistent 

with CWA section 303(c) and the 

implementing regulations at 40 CFR part 

131, then the federal cadmium and 

copper aquatic life criteria would no 

longer apply to that water body. Instead, 

any criteria associated with the newly 

designated highest attainable use would 

apply to that water body. 

B. Site-Specific Criteria 

The regulations at 40 CFR 131.11 

specify requirements for modifying 

water quality criteria to reflect sitespecific conditions. In the context of 

this rulemaking, a site-specific criterion 

(SSC) is an alternative value to the 

federal freshwater cadmium or copper 

aquatic life criteria that would be 

applied on a watershed, area-wide, or 

water body-specific basis that meets the 

regulatory test of protecting the 

designated use, being scientifically 

defensible, and ensuring the protection 

and maintenance of downstream WQS. 

A SSC may be more or less stringent 

than the otherwise applicable federal 

criteria. A SSC may be appropriate 

when further scientific data and 

analyses can bring added precision to 

express the concentration of cadmium 

and/or copper that protects the aquatic 

life-related designated use in a 

particular water body. 

C. Variances 

40 CFR part 131 defines WQS 

variances at § 131.3(o) as time-limited 

designated uses and supporting criteria 

for a specific pollutant(s) or water 

quality parameter(s) that reflect the 

highest attainable conditions during the 

term of the WQS variance. WQS 

variances adopted in accordance with 

40 CFR part 131 allow states and 

authorized tribes to address water 

quality challenges in a transparent and 

predictable way. Variances help states 

and authorized tribes focus on making 

incremental progress in improving 

water quality, rather than pursuing a 

downgrade of the underlying water 

quality goals through a designated use 

change, when the current designated 

use is difficult to attain. Oregon has 

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Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 22563 

26The estimated costs using a 7% discount rate 

range from $0.1 million to $22.6 million. 

sufficient authority to use variances 

when implementing the criteria, as long 

as such variances are adopted consistent 

with 40 CFR 131.14. Oregon may use its 

currently EPA-approved variance 

procedures with respect to a temporary 

modification of its uses as it pertains to 

any federal criteria (see OAR 340–041– 

0059) when adopting such variances. 

D. Compliance Schedules 

EPA’s regulations at 40 CFR 122.47 

and 40 CFR 131.15 allow states and 

authorized tribes to include permit 

compliance schedules in their NPDES 

permits if dischargers need additional 

time to meet their WQBELs based on the 

applicable WQS. EPA’s updated 

regulations at 40 CFR part 131 also 

include provisions authorizing the use 

of permit compliance schedules to 

ensure that a decision to allow permit 

compliance schedules includes public 

engagement and transparency (80 FR 

51022, August 21, 2015). Oregon already 

has an EPA-approved regulation 

authorizing the use of permit 

compliance schedules (see OAR 340– 

041–0061), consistent with 40 CFR 

131.15. That state regulation is not 

affected by this rule, and Oregon is 

authorized to grant compliance 

schedules, as appropriate, based on the 

federal criteria. 

IX. Economic Analysis 

EPA’s proposed cadmium and copper 

criteria may serve as a basis for 

development of NPDES permit limits. 

Oregon has NPDES permitting authority, 

and retains considerable discretion in 

implementing standards. EPA evaluated 

the potential costs to NPDES dischargers 

associated with state implementation of 

EPA’s proposed criteria. This analysis is 

documented in Economic Analysis for 

the Proposed Rule: Aquatic Life Criteria 

for Copper and Cadmium in Oregon, 

which can be found in the record for 

this rulemaking. 

Any NPDES-permitted facility that 

discharges cadmium or copper in 

Oregon could potentially incur 

compliance costs. The types of affected 

facilities could include industrial 

facilities and POTWs discharging 

treated wastewater to surface waters 

(i.e., point sources). EPA expects that 

dischargers would use similar process 

and treatment controls to come into 

compliance with the proposed cadmium 

and copper criteria as they would to 

comply with Oregon’s existing aquatic 

life criteria for cadmium and copper 

(i.e., ‘‘baseline criteria’’). EPA estimates 

the incremental impacts of the proposed 

rule against a baseline of full 

implementation of currently approved 

criteria. 

For this analysis, EPA did not 

estimate the potential for costs to 

stormwater or nonpoint sources such as 

agricultural runoff. EPA recognizes that 

Oregon may require controls for 

nonpoint sources. However, it is 

difficult to model and evaluate the 

potential cost impacts of this rule to 

those sources because they are 

intermittent, variable, and occur under 

hydrologic or climatic conditions 

associated with precipitation events. 

Also, baseline total maximum daily 

loads (TMDLs) for waters with baseline 

impairment for cadmium or copper have 

not yet been developed. Therefore, 

determining which waters would not 

achieve standards based on the 

proposed aquatic life criteria after 

complying with existing (baseline) 

regulations and policies may not be 

possible. 

A. Identifying Affected Entities 

For economic analysis purposes, EPA 

developed hypothetical applications of 

the proposed cadmium and copper 

criteria using conservative estimates for 

hardness and the BLM inputs, 

respectively. The criteria that EPA 

derived for the cost analysis would 

likely be different from and possibly 

lower (more stringent) than the actual 

criteria applications that Oregon would 

derive using ambient data from each 

water body. As described earlier in this 

proposed rule, EPA recommends that 

Oregon collect sufficiently 

representative ambient data to derive 

the most accurate and protective 

cadmium and copper aquatic life 

criteria. 

Using the criteria derived for the cost 

analysis, EPA identified 10 point source 

facilities that could potentially be 

affected by the rule—all are major 

dischargers. Major facilities are typically 

those that discharge more than 1 million 

gallons per day (mgd). Of these 

potentially affected facilities, 7 are 

POTWs and 3 are industrial dischargers. 

EPA did not include facilities covered 

by general permits in its analysis 

because data for such facilities are 

limited, and flows are usually much 

lower. EPA did not have cadmium or 

copper effluent data to evaluate minor 

facilities for this preliminary analysis. 

B. Method for Estimating Costs 

EPA estimated costs for the 10 

potentially affected facilities. EPA 

evaluated existing baseline permit 

conditions, reasonable potential to 

exceed estimates of the aquatic life 

criteria based on the proposed rule, and 

potential to exceed projected effluent 

limitations based on available effluent 

monitoring data. In instances of 

exceedances of projected effluent 

limitations under the proposed criteria, 

EPA determined the likely compliance 

scenarios and costs. Only compliance 

actions and costs that would be needed 

above the baseline level of controls are 

attributable to the proposed rule. 

EPA assumed that dischargers would 

pursue the least cost means of 

compliance with WQBELs. Incremental 

compliance actions attributable to the 

proposed rule may include pollution 

prevention, end-of-pipe treatment, and 

alternative compliance mechanisms 

(e.g., variances). EPA annualized capital 

costs over an assumed technology 

lifespan of 20 years, adding recurring 

Operation & Maintenance costs, and 

discounted using 3% and 7% discount 

rates to obtain total annual costs per 

facility. 

C. Results 

Based on the results for 10 facilities, 

EPA estimated a total incremental 

annual cost attributable to the proposed 

criteria of approximately $0.1 million to 

$18.2 million at a 3% discount rate.26

The low end of the range reflects the 

assumption that achieving very low 

copper limits is infeasible (e.g., 

available treatment technologies cannot 

consistently achieve the limits) and 

dischargers will need to apply for 

variances. The high end of the range 

reflects the assumption that dischargers 

can achieve the projected effluent limits 

through end-of-pipe treatment. All of 

the incremental costs are attributable to 

municipal and industrial dischargers for 

treatment of copper. There was no 

reasonable potential to exceed the 

proposed acute cadmium criterion. 

If the revised criteria result in an 

incremental increase in impaired 

waters, resulting in the need for TMDL 

development, there could also be some 

costs to nonpoint sources of metals. 

Using available ambient monitoring 

data, EPA compared cadmium and 

copper concentrations to the baseline 

and proposed criteria, identifying 

waterbodies that may be incrementally 

impaired (i.e., impaired under the 

proposed criteria but not under the 

baseline). Baseline impairment ranged 

from 8 to 46 stations, depending on 

whether EPA used impaired water body 

information from 2010 or 2012. Using 

available monitoring data, EPA 

identified copper impairments at 82 

monitoring stations based on the 

proposed criteria. Therefore, water 

quality data indicate potential for 

incremental impairment at 36 to 74 

stations. This increase suggests that 

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22564 Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 

27U.S. 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), which becomes $37,000 to $40,000 

using the Consumer Price Index to escalate to 2015 

dollars. 

nonpoint sources may bear some 

compliance costs, although data are not 

available to estimate the magnitude of 

these costs. If the net increase in 

stations (36 to 74) is an indication of the 

potential increase in the number of 

TMDLs, then the costs for TMDL 

development could range from 

approximately $1.3 million (36 TMDLs 

× $37,000) to $3.0 million (74 TMDLs × 

$40,000) 27. The control of nonpoint 

sources such as in the context of a 

TMDL could result in less stringent 

requirements, and thus lower costs, for 

point sources. 

X. Statutory and Executive Order 

Reviews 

A. Executive Order 12866 (Regulatory 

Planning and Review) and Executive 

Order 13563 (Improving Regulation and 

Regulatory Review) 

This action is not a significant 

regulatory action and was therefore not 

submitted to the Office of Management 

and Budget (OMB) for review. The 

proposed rule does not establish any 

requirements directly applicable to 

regulated entities or other sources of 

toxic pollutants. However, these WQS 

may serve as a basis for development of 

NPDES permit limits. Oregon has 

NPDES permitting authority, and retains 

considerable discretion in implementing 

standards. In the spirit of Executive 

Order 12866, EPA evaluated the 

potential costs to NPDES dischargers 

associated with state implementation of 

EPA’s proposed criteria. This analysis, 

Economic Analysis for the Proposed 

Rule: Aquatic Life Criteria for Copper 

and Cadmium in Oregon, is summarized 

in section IX of the preamble and is 

available in the docket. 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

PRA. While actions to implement these 

WQS could entail additional paperwork 

burden, this action does not directly 

contain any information collection, 

reporting, or record-keeping 

requirements. 

C. Regulatory Flexibility Act 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action will not 

impose any requirements on small 

entities. Small entities, such as small 

businesses or small governmental 

jurisdictions, are not directly regulated 

by this rule. 

D. Unfunded Mandates Reform Act 

This action does not contain any 

unfunded mandate as described in 

UMRA, 2 U.S.C. 1531–1538, and does 

not significantly or uniquely affect small 

governments. As these water quality 

criteria are not self-implementing, the 

action imposes no enforceable duty on 

any state, local or tribal governments or 

the private sector. 

E. Executive Order 13132 (Federalism) 

This action does not have federalism 

implications. It will not have substantial 

direct effects on the states, on the 

relationship between the national 

government and the states, or on the 

distribution of power and 

responsibilities among the various 

levels of government. This rule does not 

alter Oregon’s considerable discretion in 

implementing these WQS, nor would it 

preclude Oregon from adopting WQS 

that meet the requirements of the CWA, 

either before or after promulgation of 

the final rule, which would eliminate 

the need for federal standards upon EPA 

approval. Thus, Executive Order 13132 

does not apply to this action. 

In the spirit of Executive Order 13132 

and consistent with EPA policy to 

promote communications between EPA 

and state and local governments, EPA 

specifically solicits comments on this 

proposed action from state and local 

officials. 

F. Executive Order 13175 (Consultation 

and Coordination With Indian Tribal 

Governments) 

This action does not have tribal 

implications as specified in Executive 

Order 13175. This proposed rule does 

not impose substantial direct 

compliance costs on federally 

recognized tribal governments, nor does 

it substantially affect the relationship 

between the federal government and 

tribes, or the distribution of power and 

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. EPA developed 

the criteria in this proposed rule to 

protect aquatic life in Oregon from the 

effects of exposure to harmful levels of 

cadmium and copper. 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, EPA consulted with tribal 

officials during the development of this 

action. On November 23, 2015, EPA sent 

a letter to tribal leaders in Oregon 

offering to consult on the proposed 

cadmium and copper criteria in this 

rule. On December 15, 2015, EPA held 

a conference call with tribal water 

quality technical contacts to explain 

EPA’s proposed action and timeline. 

Formal consultation on the proposed 

action was not requested by any of the 

tribes. EPA will continue to 

communicate with the tribes prior to its 

final action. 

G. Executive Order 13045 (Protection of 

Children From Environmental Health 

and Safety Risks) 

EPA interprets Executive Order 13045 

as applying only to those regulatory 

actions that concern environmental 

health or safety risks that EPA has 

reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because it does not concern an 

environmental health risk or safety risk. 

H. Executive Order 13211 (Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use) 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

I. National Technology Transfer and 

Advancement Act of 1995 

This proposed rulemaking does not 

involve technical standards. 

J. Executive Order 12898 (Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations) 

The human health or environmental 

risk addressed by this action will not 

have potential disproportionately high 

and adverse human health or 

environmental effects on minority, lowincome or indigenous populations. The 

criteria in this proposed rule 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, Indians— 

lands, Incorporation by reference, 

Intergovernmental relations, Reporting 

and recordkeeping requirements, Water 

pollution control. 

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Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 22565 

Dated: March 31, 2016. 

Gina McCarthy, 

Administrator. 

For the reasons set forth in the 

preamble, EPA proposes to amend 40 

CFR part 131 as follows: 

PART 131—WATER QUALITY 

STANDARDS 

■ 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 

■ 2. Add § 131.46 to read as follows: 

§ 131.46 Aquatic Life Criteria for Copper 

and Cadmium in Oregon. 

(a) Scope. This section promulgates 

aquatic life criteria for cadmium and 

copper in freshwaters in Oregon. 

(b) Criteria for cadmium and copper 

in Oregon. The aquatic life criteria in 

Table 1 apply to all freshwaters in 

Oregon where fish and aquatic life are 

a designated use. 

TABLE 1—PROPOSED CADMIUM AND COPPER AQUATIC LIFE CRITERIA FOR OREGON FRESHWATERS

Metal CAS No. Criterion Maximum Concentration (CMC) 3

(μg/L) 

Criterion 

Continuous 

Concentration 

(CCC) 4

(μg/L) 

Cadmium 1 2 ..................................... 7440439 [e (0.9789 × ln(hardness) ¥ 3.866)] × CF ............................................................

Where CF = 1.136672 ¥ [(ln hardness) × (0.041838)] 

Copper 1 ........................................... 7440508 Acute (CMC) and chronic (CCC) freshwater copper criteria shall be developed using EPA’s 

2007 Aquatic Life Ambient Freshwater Quality Criteria—Copper (EPA–822–R–07–001), 

which incorporates use of the copper biotic ligand model (BLM). 

Where sufficiently representative ambient data for DOC, calcium, magnesium, sodium, potassium, sulfate, chloride, or alkalinity are not available, the state shall use the 10th percentile estimated values from Table 2 of paragraph (c) of this section based on the applicable ecoregion (or Table 3 of paragraph (c) of this section, based on the applicable 

ecoregion and stream order). 

The final copper criteria shall be calculated as no greater than the 10th percentile of the 

distribution of individual BLM outputs at a site. If 10 or fewer BLM outputs are available for 

a given site, the lowest individual acute and chronic BLM output values shall be used as 

the final acute and chronic copper criteria for that site. 

1The criteria for cadmium and copper are expressed as dissolved metal concentrations. 

2 CF is the conversion factor used to convert between the total recoverable and dissolved forms of cadmium. The term (ln hardness) in the 

CMC and the CF equation is the natural logarithm of the ambient hardness in mg/L (CaCO3). A default hardness concentration of 25 mg/L shall 

be used to calculate cadmium criteria in the absence of sufficiently representative ambient hardness data. A hardness concentration of 25 mg/L 

equates to a one-hour average dissolved cadmium concentration of 0.49 μg/L. 3The CMC is the highest allowable one-hour average instream concentration of cadmium or copper. The CMC is not to be exceeded more 

than once every three years. The CMC is rounded to two significant figures. 4The CCC is the highest allowable four-day average instream concentration of copper. The CCC is not to be exceeded more than once every 

three years. The CCC is rounded to two significant figures. 

(c) Estimated Values to Derive Copper 

Criteria. The default inputs to calculate 

copper criteria using the BLM in the 

absence of sufficiently representative 

ambient data are shown in Tables 2 and 

3. 

TABLE 2—BLM DEFAULT INPUTS FOR EACH LEVEL III ECOREGION IN OREGON

Level III Ecoregion Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

1 Coast Range .......................................................................... 8.4 3.2 4.1 0.64 33 3.2 4.8 0.7 

3 Willamette Valley ................................................................... 8.2 2.9 4.4 0.90 30 4.7 3.8 0.4 

4 Cascades ............................................................................... 6.6 2.9 3.5 0.74 35 2.2 3.2 0.3 

9 Eastern Cascades Slopes and Foothills ............................... 8.2 3.8 6.0 1.0 44 3.2 5.0 0.5 

10 Columbia Plateau ................................................................ 15 5.2 9.3 1.8 40 3.3 10 1.0 

11 Blue Mountains .................................................................... 11 3.9 7.7 1.4 49 3.3 7.1 0.8 

12 Snake River Plain ................................................................ 33 10 13 2.3 109 10 22 1.2 

78 Klamath Mountains .............................................................. 8.7 4.6 4.0 0.66 44 2.1 3.5 0.6 

80 Northern Basin and Range .................................................. 26 8.2 20 2.7 89 15 24 1.0 

TABLE 3—BLM DEFAULT INPUTS FOR EACH STREAM ORDER WITHIN EACH LEVEL III ECOREGION IN OREGON

Level III Ecoregion Stream 

order 

Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

1 Coast Range ........................................................ SO 1–3 6.0 0.8 1.3 0.1 44 0.6 1.1 0.7 

SO 4–6 3.6 1.0 2.0 0.2 15 1.6 2.2 0.7 

SO 7–9 12 3.4 4.3 0.8 56 2.3 6.3 0.7 

3 Willamette Valley ................................................. SO 1–3 9.9 3.8 5.6 1.5 ................ 2.3 1.5 0.4 

SO 4–6 7.1 2.5 4.3 0.8 29 4.6 2.8 0.4 

SO 7–9 5.0 1.6 3.4 0.6 20 2.7 2.3 0.4 

4 Cascades ............................................................. SO 1–3 1.0 0.2 1.8 0.2 ................ 0.5 0.2 0.3 

SO 4–6 3.5 1.0 2.8 0.4 16 0.8 0.8 0.3 

SO 7–9 13 3.6 3.7 0.9 52 1.7 6.9 0.3 

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22566 Federal Register / Vol. 81, No. 74 / Monday, April 18, 2016 / Proposed Rules 

TABLE 3—BLM DEFAULT INPUTS FOR EACH STREAM ORDER WITHIN EACH LEVEL III ECOREGION IN OREGON—Continued 

Level III Ecoregion Stream 

order 

Calcium 

(mg/L) 

Magnesium 

(mg/L) 

Sodium 

(mg/L) 

Potassium 

(mg/L) 

Alkalinity 

(mg/L) 

Chloride 

(mg/L) 

Sulfate 

(mg/L) DOC 

9 Eastern Cascades Slopes and Foothills ............. SO 1–3 4.4 0.9 2.3 0.4 35 0.2 0.2 0.5 

SO 4–6 5.5 0.8 2.4 0.5 22 0.9 2.2 0.5 

SO 7–9 ................ .................... ................ .................. ................ ................ ................ 0.5 

10 Columbia Plateau .............................................. SO 1–3 24.0 9.4 10.2 1.4 127 4.6 11 1.0 

SO 4–6 8.6 3.2 4.0 0.9 33 1.4 3.1 1.0 

SO 7–9 5.7 1.5 2.0 0.7 16 0.8 4.2 1.0 

11 Blue Mountains .................................................. SO 1–3 8.6 3.2 ................ .................. 169 ................ ................ 0.8 

SO 4–6 3.7 0.8 1.6 0.7 16 0.3 0.7 0.8 

SO 7–9 8.5 1.5 3.3 0.7 32 0.8 5.0 0.8 

12 Snake River Plain .............................................. SO 1–3 13 2.0 6.1 0.8 35 1.4 3.7 1.2 

SO 4–6 13 2.5 4.9 1.2 40 2.2 3.8 1.2 

SO 7–9 37 10 13 2.5 122 11 30 1.2 

78 Klamath Mountains ............................................ SO 1–3 ................ .................... ................ .................. ................ 2.1 ................ 0.6 

SO 4–6 7.9 3.2 4.0 0.6 36 2.1 2.4 0.6 

SO 7–9 ................ .................... ................ .................. ................ ................ ................ 0.6 

80 Northern Basin and Range ................................ SO 1–3 6.3 1.1 4.3 2.2 24 0.2 2.5 1.0 

SO 4–6 15 5.7 4.1 0.8 54 2.0 9.3 1.0 

SO 7–9 8.9 2.4 7.7 2.1 ................ 2.1 5.1 1.0 

(d) Applicability. (1) The criteria in 

paragraph (b) of this section are the 

applicable acute cadmium and acute 

and chronic copper aquatic life criteria 

in all freshwaters in Oregon where fish 

and aquatic life are a designated use. 

After the effective date of this rule, in 

cases where EPA determines that state 

cadmium or copper aquatic life criteria 

meet the requirements of Clean Water 

Act section 303(c) and 40 CFR part 131, 

Oregon’s cadmium or copper criteria 

will apply rather than the criteria in 

paragraph (b) of this section. 

(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 

freshwaters in Oregon where fish and 

aquatic life are a designated use. 

(i) 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; 

otherwise the criteria apply throughout 

the water body including at the end of 

any discharge pipe, conveyance or other 

discharge point. 

(ii) The state shall not use a low flow 

value that is less stringent than the 

values listed below for waters suitable 

for the establishment of low flow return 

frequencies (i.e., streams and rivers) 

when calculating the available dilution 

for the purposes of determining the 

need for and establishing Water QualityBased Effluent Limitations in National 

Pollutant Discharge Elimination System 

permits: 

Acute criteria (CMC) ............... 1Q10 or 1B3. 

Chronic criteria (CCC) ............ 7Q10 or 4B3. 

Where: 

1. 1Q10 is the lowest one-day average 

flow event expected to occur once 

every ten years, on average (determined hydrologically). 

2. 1B3 is the lowest one-day average 

flow event expected to occur once 

every three years, on average (determined biologically). 

3. 7Q10 is the lowest seven-consecutive-day average flow event expected 

to occur once every ten years, on average (determined hydrologically). 

4. 4B3 is the lowest four-consecutiveday average flow event expected to 

occur once every three years, on average (determined biologically). 

[FR Doc. 2016–08038 Filed 4–15–16; 8:45 am] 

BILLING CODE 6560–50–P 

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