Document ID: EPA-HQ-OW-2016-0012-0148
Agency: epa
Document Type: Rule
Title: Aquatic Life Criteria: Cadmium in Oregon
Posted Date: 2017-02-03T05:00Z

[Federal Register Volume 82, Number 22 (Friday, February 3, 2017)]
[Rules and Regulations]
[Pages 9166-9174]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-02283]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

[EPA-HQ-OW-2016-0012; FRL-9958-40-OW]
RIN 2040-AF60

Aquatic Life Criteria for Cadmium in Oregon

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is establishing a 
federal Clean Water Act (CWA) aquatic life criterion for freshwaters 
under the state of Oregon's jurisdiction, to protect aquatic life from 
the effects of exposure to harmful levels of 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. Since that 
time, the state adopted revised criteria for copper (which EPA is 
approving in parallel with this final rulemaking), but has not adopted 
a revised acute criterion for cadmium and thus EPA is establishing a 
federal freshwater acute criterion for cadmium that takes into account 
the best available science, EPA policies, guidance and legal 
requirements, to protect aquatic life uses in Oregon.

DATES: This final rule is effective on March 6, 2017.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OW-2016-0012. All documents in the docket are listed on the 
http://www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available electronically through http://www.regulations.gov.

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 final rule is organized as follows:

I. General Information
    A. Does this action apply to me?
    B. How did EPA develop this final rule?
II. Background
    A. Statutory and Regulatory Background
    B. EPA's Actions on 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. Final Acute Cadmium Criterion for Oregon's Freshwaters
    C. Additional Considerations for Calculation of Site-Dependent 
Cadmium Criteria
IV. Implementation of Final Cadmium Criterion in Oregon
V. Critical Low-Flows and Mixing Zones
VI. Endangered Species Act
VII. Applicability of Criteria
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)
    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

[[Page 9167]]

    J. Executive Order 12898 (Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations)
    K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

    Cadmium naturally occurs at low levels in surface waters, but 
anthropogenic activities can increase levels of cadmium in the 
environment. At higher concentrations, cadmium can be toxic to aquatic 
life. Sources of elevated cadmium in the environment include coal 
combustion, mining, electroplating, iron and steel production, and use 
of pigments, fertilizers and pesticides. Industrial facilities, 
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 water quality standards (WQS) 
promulgated by EPA are 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:

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                          Category                                 Examples of potentially affected entities
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Industry....................................................  Industrial facilities 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.
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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 indirectly affected by 
this rule. To determine whether your facility or activities could be 
indirectly 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?

    In developing this final rule, EPA carefully considered the public 
comments and feedback received from interested parties. EPA originally 
provided a 45-day public comment period after publishing the proposed 
rule in the Federal Register on April 18, 2016.\1\ In addition, EPA 
held two public hearings on May 16 and 17, 2016, to provide 
clarification on the contents of the proposed rule and accept verbal 
public comments.
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    \1\ See Aquatic Life Criteria for Copper and Cadmium in Oregon: 
Proposed Rule, 81 FR 22555, April 18, 2016.
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    Fourteen organizations and individuals submitted comments on a 
range of issues prior to the close of the public comment period on June 
2, 2016. Some comments addressed issues beyond the scope of the 
rulemaking, and thus EPA did not consider them in finalizing this rule. 
In each section of this preamble, EPA discusses certain public comments 
so that the public is aware of the Agency's position. For a full 
response to these and all other comments, see EPA's Response to 
Comments document in the official public docket.

II. Background

A. Statutory and Regulatory Background

    CWA section 101(a)(2) establishes as a national goal ``wherever 
attainable . . . 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 appropriate 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. For waters 
with multiple use designations, the criteria shall support the most 
sensitive use.'' In addition, 40 CFR 131.10(b) provides that ``[i]n 
designating uses of a water body and the appropriate criteria for those 
uses, the [s]tate shall take into consideration the water quality 
standards of downstream waters and shall ensure that its water quality 
standards provide for the attainment and maintenance of the water 
quality standards of downstream waters.''
    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 disapproves a state's new or revised WQS, the CWA 
provides the state 90 days to adopt a revised WQS that meets CWA 
requirements, and if it fails to do so, EPA shall promptly propose and 
then within 90 days promulgate such standard unless EPA approves a 
state replacement WQS first (CWA section 303(c)(3) and (c)(4)(A)). CWA 
section 303(c)(4)(B) authorizes the Administrator to determine that a 
new or revised standard is needed to meet CWA requirements. Upon making 
such a determination, the CWA specifies that EPA shall promptly 
propose, and then within 90 days promulgate, any such new or revised 
standard unless prior to such promulgation, the state has adopted a 
revised or new WQS that EPA determines to be in accordance with the 
CWA.
    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) 
goal uses. In establishing criteria, states should establish numeric 
water quality criteria based on EPA's CWA section 304(a) criteria, 
section 304(a) criteria modified to reflect site-specific conditions, 
or other scientifically defensible methods (40 CFR 131.11(b)(1)). In 
all cases criteria must be sufficient to protect the designated use and 
be based on sound scientific rationale (40 CFR 131.11(a)(1)).

B. EPA's Actions on Oregon's Freshwater Copper and Cadmium Criteria

    As discussed in the preamble to EPA's proposed rule (81 FR 22555; 
April 18, 2016), EPA disapproved several of Oregon's revised aquatic 
life criteria

[[Page 9168]]

under CWA 303(c), including an acute cadmium freshwater criterion, and 
acute and chronic freshwater copper criteria that the National Marine 
Fisheries Service (NMFS) concluded would jeopardize endangered species 
in Oregon in its biological opinion dated August 14, 
2012.2 3 On November 14, 2016, Oregon submitted revised 
freshwater copper criteria to EPA for review under CWA section 303(c). 
In parallel with this final rule, EPA is taking action under CWA 303(c) 
to approve the freshwater copper aquatic life criteria submitted by 
Oregon. Oregon did not adopt a revised acute cadmium criterion, 
however, therefore EPA is finalizing the freshwater acute cadmium 
criterion in this rule in accordance with CWA section 303(c)(3) and 
(c)(4) requirements.
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    \2\ See USEPA. 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.
    \3\ The NMFS biological opinion contained Reasonable and Prudent 
Alternatives (RPAs) that would avoid the likelihood of jeopardy to 
the species. For acute cadmium, the RPA specified a process for 
deriving revised freshwater criteria.
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C. General Recommended Approach for Deriving Aquatic Life Criteria

    As discussed in the preamble to the 2016 proposed rule (81 FR 
22555), 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.
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    \4\ USEPA. 1985. Guidelines for Deriving Numerical National 
Water Quality Criteria for the Protection of Aquatic Organisms and 
Their Uses. U.S. Environmental Protection Agency, Office of Research 
and Development, Duluth, MN, Narragansett, RI, Corvallis, OR. PB85-
227049. https://www.epa.gov/wqc/guidelines-deriving-numerical-national-water-quality-criteria-protection-aquatic-organisms-and.
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    Numeric criteria derived using EPA's 1985 Guidelines are expressed 
as short-term (acute) and long-term (chronic) values. The combination 
of a criteria maximum concentration (CMC), a one-hour average value, 
and a criteria continuous concentration (CCC), 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. 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 the 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).\5\
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    \5\ See USEPA, 1985. Pages. 5-7.
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    Because 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.) because 
water chemistry can influence a pollutant's bioavailability and 
toxicity. For metals in particular, EPA recommends expressing the 
criteria as functions of chemical constituents of the water, because 
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, because the concentration of dissolved metal better 
approximates the toxic fraction.\6\
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    \6\ Water Quality Standards; Establishment of Numeric Criteria 
for Priority Toxic Pollutants; States' Compliance--Revision of 
Metals Criteria, May 4, 1995, 60 FR 22229.
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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.
    On March 30, 2016, EPA announced publication of final updated 
304(a) national recommended aquatic life criteria for cadmium.\7\ The 
2016 cadmium 304(a) criteria reflect the best available science, 
including the results of laboratory aquatic toxicity tests for 75 new 
species. EPA lowered the updated 304(a) recommended freshwater acute 
cadmium criterion to protect commercially and recreationally important 
salmonids, consistent with EPA's 1985 Guidelines. In addition, EPA 
revised the effect of total hardness on cadmium toxicity using the 
newly acquired data.
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    \7\ USEPA. 2016. Aquatic Life Ambient Water Quality Criteria: 
Cadmium--2016. U.S. Environmental Protection Agency, Office of 
Water, Washington, DC EPA-820-R-16-002.
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B. Final Acute Cadmium Criterion for Oregon's Freshwaters

    To protect aquatic life in Oregon's freshwaters from acute toxic 
effects from cadmium, EPA is promulgating the one-hour average CMC of e 
(0.9789 x ln(hardness)-3.866) x CF ([micro]g/L, dissolved), 
not to be exceeded 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) x (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). Commenters were generally supportive of EPA's 
proposal to apply the final 2016 national 304(a) recommended acute 
cadmium criterion (and associated CF) to freshwaters in Oregon.
    Where site-specific hardness data are unavailable, EPA is 
establishing default hardness concentrations (as CaCO3), 
based on the 10th percentile of existing hardness concentrations in 
waters within each of the nine Level III ecoregions in Oregon. These 
ecoregion-specific default hardness concentrations are set forth in 
Table 2 in the final regulatory text for Sec.  131.46.
    To determine the default hardness concentrations, EPA used 10th 
percentile hardness estimates from Table 4 in USEPA's Recommended 
Estimates for Missing Water Quality Parameters for Application in EPA's 
Biotic Ligand Model, February 16, 2016

[[Page 9169]]

(EPA 820-R-15-106).\8\ EPA elected to rely on the dataset \9\ that 
formed the basis for the recommendations in EPA's peer-reviewed Missing 
Parameters document to determine the proposed and final defaults for 
Oregon. While not the only acceptable dataset, the dataset that EPA 
used in its Missing Parameters document is robust and publicly 
available, and is therefore a reasonable source of data to determine 
scientifically defensible and protective default hardness 
concentrations for the acute cadmium criterion. Although EPA is 
promulgating these default hardness values to use in the absence of 
ambient hardness data, EPA strongly recommends that Oregon collect 
sufficiently representative ambient hardness data to determine the 
appropriate acute cadmium criterion for a site.
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    \8\ For a map of Level III ecoregions in the continental United 
States, see: https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-continental-united-states.
    \9\ Data came from several water quality databases including the 
Storage and Retrieval Data System, National Waters Information 
System (NWIS), Wadeable Stream Assessment, and National River and 
Stream Assessment (NRSA) database.
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    Some commenters were in favor of EPA's decision to include default 
input parameters, while others were critical of this approach. 
Specifically related to EPA's proposal of a default hardness value for 
use with the acute cadmium criterion, some commenters argued that EPA's 
proposal of a default hardness value of 25 mg/L was overly conservative 
because it is below the lowest existing 10th percentile ecoregional 
hardness concentration in Oregon. EPA maintains that it is important to 
include default values for hardness to provide clarity to NPDES permit 
writers and water body assessors as to the applicable acute cadmium 
criterion at the site when there are insufficient ambient hardness data 
to adequately characterize the site. The default hardness of 25 mg/L 
that EPA proposed in its April 18, 2016 proposed rule (81 FR 22555) is 
protective and consistent with Oregon's application of a default 
hardness concentration of 25 mg/L if no hardness data are available to 
calculate hardness-dependent metals criteria.\10\ However, EPA 
recognizes that hardness concentrations vary throughout the state, and 
using more refined hardness defaults based on ecoregion-specific data, 
rather than a single statewide default hardness value, would also 
result in protective criteria in the absence of ambient hardness data. 
Therefore, in this rulemaking EPA is finalizing different default 
hardness concentrations that correspond to the 10th percentile of 
ambient hardness data from each of the nine ecoregions in Oregon.
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    \10\ 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.
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    Consistent with EPA guidance, the hardness default does not 
represent a ``hardness floor'' for the ecoregion; rather, a site's 
actual ambient water hardness should be used to calculate the criterion 
when sufficiently representative hardness data are available, even if 
ambient hardness is below the default hardness concentration.\11\
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    \11\ USEPA. 2002. National Recommended Water Quality Criteria: 
2002. U.S. Environmental Protection Agency, Office of Water, 
Washington, DC EPA-822-R-02-047.
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C. Additional Considerations for Calculation of Site-Dependent Cadmium 
Criteria

    Commenters requested that EPA provide additional specificity on the 
minimum number of samples required to adequately capture temporal and 
spatial variability at a site, and site selection considerations. While 
many of these comments were with respect to copper criteria 
calculations, EPA agrees that these are important considerations for 
cadmium as well. In response to these comments, EPA is providing the 
following recommendations.
    The number of samples needed to characterize site variability 
depends on several characteristics of the site. The water quality 
characteristics that determine the bioavailability of metals, including 
cadmium, can vary widely in both space and time, changing with 
biological activity, flow, geology, human activities, watershed 
landscape, and other features of the water body. For the state to 
ensure that the criteria are adequately protective of the most 
bioavailable conditions at the site through time, the state should 
apply appropriate methods to evaluate how a site's water quality 
conditions are expected to vary temporally, and ensure that adequate 
monitoring is in place to capture the variability across the site and 
through time.
    The state should first demonstrate that the hardness concentrations 
used in the calculations are not biased toward less bioavailable 
conditions for cadmium by evaluating the hardness data and resultant 
acute cadmium criteria that are calculated over time for different 
flows and seasons. The state should use appropriate analytical methods, 
such as a Monte Carlo \12\ simulation or another analytical tool, to 
determine if the monitoring methods are sufficient to capture the 
temporal trends, and the resultant calculated criteria are adequate to 
represent the most bioavailable conditions over time at the site.
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    \12\ Given sufficient data, Monte Carlo simulation or equivalent 
analysis can be used to determine the probability of identifying the 
most bioavailable time period for a series of monitoring scenarios. 
From such an analysis, the state can select the appropriate 
monitoring regime.
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    Oregon should consider the following when defining a site to which 
to apply criteria for cadmium: (1) Metals are generally persistent, so 
calculating the criterion using input parameter values from a location 
at or near the discharge point could result in a criterion that is not 
protective of areas that are outside of that location, 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.\13\ Additionally, pursuant to 
40 CFR 131.10(b), Oregon must consider downstream WQS when calculating 
a protective criterion in upstream waters.
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    \13\ USEPA. 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.
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    Substantial changes in a site's ambient hardness will likely affect 
the bioavailability of and the relevant criterion for cadmium at that 
site. In addition, with regular monitoring and a robust, site-specific 
dataset, criteria can be developed that more accurately reflect site 
conditions than criteria set using default values or limited data sets. 
Therefore, EPA recommends that Oregon periodically revisit each water 
body's cadmium criterion and re-run the hardness equation when changes 
in water chemistry are evident or suspected at a site, and also as 
additional monitoring data become available.
    When Oregon calculates cadmium criteria, to promote transparency 
and ensure predictable and repeatable outcomes, EPA recommends that the 
state make each site's ambient hardness data used in the cadmium 
criteria calculations, resultant numeric criteria, and the geographic 
extent of the site publicly available on the state's Web site.

IV. Implementation of Final Cadmium Criterion in Oregon

    Because organisms are more sensitive to cadmium when hardness is 
low, Oregon should ensure that sufficiently representative ambient 
hardness data are collected to have confidence that critical conditions 
in the water body are

[[Page 9170]]

being adequately captured. When setting Water Quality-Based Effluent 
Limitations (WQBELs) for cadmium, Oregon should determine hardness 
values that represent the receiving water both upstream of and below 
the point of discharge under critical conditions (i.e., low hardness) 
when cadmium bioavailability is expected to be greater, such that the 
resulting criteria calculations, reasonable potential analyses, and any 
effluent limitations will be protective of the entire site at 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.\14\ The same principle holds for developing a TMDL 
target.
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    \14\ USEPA. 2010. NPDES Permit Writers' Manual. U.S. 
Environmental Protection Agency, Office of Water, Washington, DC 
EPA-833-K-10-001. September 2010.
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    For transparency for the public, EPA recommends that Oregon 
describe in its NPDES permit factsheets how the numeric criteria were 
calculated and used to determine reasonable potential and derive 
WQBELs. Similarly for TMDLs, EPA recommends that Oregon describe in the 
TMDL document how the numeric criteria were calculated and used to 
determine TMDL targets. In the assessment and listing context, EPA 
recommends that Oregon describe in its integrated reports how it 
calculated numeric criteria to which it compared ambient cadmium 
concentrations.

V. Critical Low-Flows and Mixing Zones

    To ensure that the criteria are applied appropriately to protect 
Oregon's aquatic life uses, EPA is establishing 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.\15\
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    \15\ USEPA. 2014. Water Quality Standards Handbook-Chapter 5: 
General Policies. U.S. Environmental Protection Agency, Office of 
Water. Washington, DC EPA-820-B-14&-004. http://www.epa.gov/sites/production/files/2014-09/documents/handbook-chapter5.pdf.
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    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.\16\ The hydrologically based critical low-flow value is determined 
statistically using probability and extreme values, while the 
biologically based critical low-flow is determined empirically using 
the specific duration and frequency associated with the criterion.
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    \16\ USEPA. 1991. Technical Support Document For Water Quality-
based Toxics Control. U.S. Environmental Protection Agency, Office 
of Water, Washington, DC EPA/505/2-90-001. http://www3.epa.gov/npdes/pubs/owm0264.pdf.
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    For the freshwater acute cadmium criterion, EPA establishes the 
following critical low-flow values: 1Q10 or 1B3. Using the 
hydrologically based method, the 1Q10 represents the lowest one-day 
average flow event expected to occur once every ten years, on average. 
Using the biologically based method, 1B3 represents the lowest one-day 
average flow event expected to occur once every three years, on 
average.\17\
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    \17\ See USEPA, 2014.
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    The criterion in this final rule applies at the point of discharge 
unless Oregon authorizes a mixing zone. Where Oregon authorizes a 
mixing zone, the criterion applies at the locations allowed by the 
mixing zone (i.e., the CMC would apply at the defined boundary of the 
acute mixing zone).\18\
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    \18\ See USEPA, 1991.
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    One commenter argued that EPA's proposed critical low-flow 
provisions were unnecessary, asserting that Oregon already has such 
provisions. Currently Oregon's implementation methods for low-flows are 
in non-binding guidance. Specifying the appropriate low-flow provisions 
in regulation will provide added clarity, and ensure that the acute 
cadmium criterion is implemented in such a way that designated uses are 
protected.

VI. Endangered Species Act

    As noted in the 2016 proposed rule, the NMFS 2012 biological 
opinion concluded that the freshwater acute cadmium criterion that 
Oregon adopted in 2004 would jeopardize the continued existence of 
specific endangered species and their critical habitat in Oregon. The 
opinion also contained a reasonable and prudent alternative (RPA) for 
cadmium that would avoid the likelihood of jeopardy to endangered 
species in Oregon.
    EPA has determined that the acute cadmium criterion being finalized 
in this rulemaking is consistent with the RPA for acute cadmium as 
contained in the NMFS 2012 biological opinion. Therefore, as finalized, 
the acute cadmium criterion for Oregon is sufficiently protective of 
threatened and endangered species in state waters and avoids the 
likelihood of jeopardizing the continued existence of listed species or 
resulting in the destruction or adverse modification of critical 
habitat. EPA's RPA analysis for the acute cadmium criterion is 
contained in the docket for this rule.

VII. Applicability of Criteria

    Under the CWA, Congress gave states primary responsibility for 
developing and adopting WQS for their navigable waters (CWA section 
303(a)-(c)). Although EPA is establishing an acute cadmium criterion 
for Oregon's freshwaters to remedy EPA's 2013 disapproval of Oregon's 
2004 criteria, Oregon continues to have the option to adopt and submit 
to EPA an acute cadmium criterion for the state's freshwaters 
consistent with CWA section 303(c) and EPA's implementing regulations 
at 40 CFR part 131.
    In its April 18, 2016, proposed rule, EPA proposed that if Oregon 
adopted and submitted freshwater cadmium and/or copper aquatic life 
criteria after EPA's finalization of the freshwater acute cadmium 
criterion and freshwater acute and chronic copper criteria, then once 
EPA approved Oregon's WQS, those EPA-approved criteria in Oregon's WQS 
would automatically become solely effective for CWA purposes and EPA's 
promulgated criteria would no longer apply. EPA did not receive any 
comments on this provision as it relates to copper and cadmium criteria 
for Oregon, and this provision is moot with respect to copper since 
Oregon adopted revised freshwater copper criteria (which EPA is 
approving in parallel with this final acute cadmium criterion 
rulemaking). However, upon further consideration of comments received 
on other proposed rules where EPA proposed a similar provision, EPA 
decided not to finalize this provision. Pursuant to 40 CFR 131.21(c), 
EPA's federally promulgated WQS are and will be applicable for purposes 
of the CWA until EPA withdraws those federally promulgated WQS. EPA 
would expeditiously undertake such a rulemaking to withdraw the federal

[[Page 9171]]

acute cadmium criterion if and when Oregon adopts and EPA approves a 
corresponding criterion that meets the requirements of section 303(c) 
of the CWA and EPA's implementing regulations at 40 CFR part 131.

VIII. Alternative Regulatory Approaches and Implementation Mechanisms

    Oregon has considerable discretion to implement the acute cadmium 
aquatic life criterion 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 this section.

A. Designating Uses

    EPA's final acute cadmium criterion applies 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 specify how states and authorized 
tribes establish, modify or remove designated uses for their waters. 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,\19\ and EPA finds that removal to be consistent 
with CWA section 303(c) and EPA's implementing regulations at 40 CFR 
part 131, then the federal acute cadmium criterion would no longer 
apply to that water body. Instead, any criterion associated with the 
newly designated highest attainable use would apply to that water body.
---------------------------------------------------------------------------

    \19\ Highest attainable use is the modified aquatic life, 
wildlife, or recreation use that is both closest to the uses 
specified in section 101(a)(2) of the Act and attainable, based on 
the evaluation of the factor(s) in Sec.  131.10(g) that preclude(s) 
attainment of the use and any other information or analyses that 
were used to evaluate attainability. There is no required highest 
attainable use where the state demonstrates the relevant use 
specified in section 101(a)(2) of the Act and sub-categories of such 
a use are not attainable (see 40 CFR 131.3(m)).
---------------------------------------------------------------------------

B. Site-Specific Criteria

    EPA's regulations at 40 CFR 131.11 specify requirements for 
establishing criteria to protect designated uses, including criteria 
modified to reflect site-specific conditions. In the context of this 
rulemaking, a site-specific criterion (SSC) is an alternative value to 
the federal freshwater acute cadmium criterion 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 criterion. A SSC may be appropriate when further scientific 
data and analyses can bring added precision to express the 
concentration of cadmium that protects the aquatic life-related 
designated use in a particular water body. As discussed earlier, if 
Oregon adopts and EPA approves site-specific criteria that fully meet 
the requirements of section 303(c) of the CWA and EPA's implementing 
regulations at 40 CFR part 131, EPA will undertake a rulemaking to 
withdraw the corresponding federal criterion.

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 variances. 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 designated use is not attainable throughout the 
term of the variance due to one of the factors listed in 40 CFR 131.14. 
Oregon has sufficient authority to use variances when implementing the 
final acute cadmium criterion, as long as such variances are adopted 
consistent with 40 CFR 131.14, and submitted to EPA for review under 
CWA section 303(c).

D. Compliance Schedules

    EPA's regulations at 40 CFR 122.47 provide the requirements when 
states and authorized tribes wish 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 131.15 require any state or authorized tribe 
wishing to use permit compliance schedules to also include provisions 
authorizing the use of permit compliance schedules after appropriate 
public involvement to ensure that a decision to allow permit compliance 
schedules derives from and complies with the applicable WQS. (80 FR 
51022, August 21, 2015). Oregon may use its EPA-approved regulation 
authorizing the use of permit compliance schedules (see OAR 340-041-
0061), consistent with 40 CFR 131.15, to grant compliance schedules, as 
appropriate, for WQBELs based on the federal acute cadmium criterion. 
That state regulation is not affected by this final rule.

IX. Economic Analysis

    Although EPA's final acute cadmium criterion itself will not impose 
any direct requirements on entities, this criterion may ultimately 
serve as a basis for development of new or revised NPDES permit limits. 
Oregon has NPDES permitting authority, and retains considerable 
discretion in implementing standards. Still, to best inform the public 
of the potential impacts of this rule, EPA evaluated the potential 
costs associated with state implementation of EPA's final criterion. 
This analysis is documented in Economic Analysis for the Final Rule: 
Aquatic Life Criteria for Cadmium in Oregon, which can be found in the 
record for this rulemaking.
    For the economic analysis, EPA assumed the baseline to be full 
implementation of currently approved existing aquatic life criteria 
(i.e., ``baseline criteria'') and then estimated the incremental 
impacts for compliance with the final cadmium criterion in this rule. 
For point source costs, any NPDES-permitted facility that discharges 
cadmium could potentially incur compliance costs. The types of affected 
facilities could include industrial facilities and publicly owned 
treatment works (POTWs) discharging sanitary 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 
final cadmium criterion as they would to comply with Oregon's baseline 
criteria.
    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 have not yet

[[Page 9172]]

been developed; therefore, determining which waters would not achieve 
standards based on the final aquatic life criterion after complying 
with existing (baseline) regulations and policies may not be possible.

A. Identifying Affected Entities

    For identifying new criteria values for the purposes of estimating 
cost incremental to costs to achieve the existing baseline criteria, 
EPA developed hypothetical applications of the final cadmium criterion 
using conservative estimates for hardness. The criteria that EPA 
calculated for the economic analysis are likely different from and 
possibly lower (more stringent) than the actual criteria applications 
that Oregon would calculate using ambient data from each water body. As 
described earlier in this final rule, EPA recommends that Oregon 
collect sufficiently representative ambient data to calculate the most 
accurate and protective cadmium criteria by site.
    Using the criteria calculated for the cost analysis, EPA identified 
12 point source facilities with sufficient data for evaluation \20\ 
that could potentially be affected by the rule--all are major 
dischargers. Major discharge facilities are typically those that 
discharge more than 1 million gallons per day (mgd). Of these 
potentially affected facilities, 10 are POTWs (municipals) and two are 
industrial dischargers. EPA did not include facilities covered by 
general permits in its analysis because none of the general permits 
reviewed include specific effluent limits or monitoring requirements 
for cadmium except for two industrial stormwater general permits that 
include monitoring requirements for cadmium, but no effluent limits. 
See the Economic Analysis for more details.
---------------------------------------------------------------------------

    \20\ EPA initially used ICIS-NPDES to identify facilities in 
Oregon whose NPDES permits contain effluent limitations and/or 
monitoring requirements for cadmium. There were neither sufficient 
nor adequate data available to evaluate those facilities. Therefore, 
EPA obtained monitoring data from the Oregon Department of 
Environmental Quality. EPA excluded biosolids data, facilities with 
ocean discharges (i.e., not freshwater), facilities where all 
reported results were non-detect, facilities with less than three 
data points, and others where there were insufficient or inadequate 
data to perform the analysis. EPA obtained facility-specific 
information from NPDES permits and fact sheets.
---------------------------------------------------------------------------

B. Method for Estimating Costs

    For facilities with available data, EPA evaluated existing baseline 
permit conditions, reasonable potential to exceed estimates of the 
aquatic life criteria based on the final rule, and potential to exceed 
projected effluent limitations based on available effluent monitoring 
data. There was no reasonable potential to exceed the final acute 
cadmium criterion.
    If the final criterion resulted in an incremental increase in 
impaired waters, resulting in the need for TMDL development, there 
could also be some costs to nonpoint sources of cadmium. Using 
available ambient monitoring data, EPA compared cadmium concentrations 
to the baseline and final criteria, identifying waterbodies that may be 
incrementally impaired (i.e., impaired under the final criteria but not 
under the baseline). EPA did not identify the potential for incremental 
impairment due to the final acute cadmium criterion.

C. Results

    As discussed above, EPA determined there are no point or nonpoint 
source costs associated with the acute cadmium criterion in this final 
rule. None of the dischargers for which monitoring data are available 
have a reasonable potential to exceed the final criterion. Therefore, 
EPA estimates that point source dischargers will not incur annual costs 
to comply with the final acute cadmium criterion. Additionally, based 
on available monitoring data, EPA did not identify any location that 
would be incrementally impaired under the final criterion. Therefore, 
EPA did not attribute any cost to nonpoint sources for compliance with 
the final acute cadmium criterion.

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 a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket.
    EPA prepared an analysis of the potential costs and benefits 
associated with this action. This analysis, Economic Analysis for the 
Final Rule: Aquatic Life Criteria for 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 any direct new information collection 
burden under the provisions of the Paperwork Reduction Act, 44 U.S.C. 
3501 et seq. Actions to implement these WQS could entail additional 
paperwork burden. Burden is defined at 5 CFR 1320.3(b). This action 
does not include 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. EPA-
promulgated standards are implemented through various water quality 
control programs including the NPDES program, which limits discharges 
to navigable waters except in compliance with an NPDES permit. The CWA 
requires that all NPDES permits include any limits on discharges that 
are necessary to meet applicable WQS. Thus, under the CWA, EPA's 
promulgation of WQS establishes standards that the state implements 
through the NPDES permit process. The state has discretion in 
developing discharge limits, as needed to meet the standards. As a 
result of this action, the State of Oregon will need to ensure that 
permits it issues include any limitations on discharges necessary to 
comply with the standards established in the final rule. In doing so, 
the state will have a number of choices associated with permit writing. 
While Oregon's implementation of the rule may ultimately result in new 
or revised permit conditions for some dischargers, including small 
entities, EPA's action, by itself, does not impose any of these 
requirements on small entities; that is, these requirements are not 
self-implementing.

D. Unfunded Mandates Reform Act

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

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

[[Page 9173]]

responsibilities among the various levels of government. This rule does 
not alter Oregon's considerable discretion in implementing these WQS, 
nor will it preclude Oregon from adopting WQS in the future that EPA 
concludes meet the requirements of the CWA, which will eliminate the 
need for federal standards. Thus, Executive Order 13132 does not apply 
to this action.

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 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 final rule to protect aquatic life 
in Oregon from the effects of exposure to harmful levels of cadmium. 
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 
criterion 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.

G. Executive Order 13045 (Protection of Children From Environmental 
Health and Safety Risks)

    This rule is not subject to Executive Order 13045, because it is 
not economically significant as defined in Executive Order 12866, and 
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 a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

I. National Technology Transfer and Advancement Act of 1995

    This final 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, low-income or indigenous 
populations. The criterion in this final rule will support the health 
and abundance of aquatic life in Oregon, and will therefore benefit all 
communities that rely on Oregon's ecosystems.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 131

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

    Dated: January 10, 2017.
Gina McCarthy,
Administrator.
    For the reasons set forth in the preamble, EPA amends 40 CFR part 
131 as follows:

PART 131--WATER QUALITY STANDARDS

0
1. The authority citation for part 131 continues to read as follows:

    Authority: 33 U.S.C. 1251 et seq.

Subpart D--Federally Promulgated Water Quality Standards

0
2. Add Sec.  131.46 to read as follows:

Sec.  131.46  Aquatic life criterion for cadmium in Oregon.

    (a) Scope. This section promulgates an acute aquatic life criterion 
for cadmium in freshwaters in Oregon.
    (b) Criterion for cadmium in Oregon. The aquatic life criterion in 
Table 1 applies to all freshwaters in Oregon where fish and aquatic 
life are a designated use.

     Table 1--Cadmium Aquatic Life Criterion for Oregon Freshwaters
------------------------------------------------------------------------
                                                    Criterion Maximum
             Metal                   CAS No.     Concentration (CMC) \3\
                                                       ([micro]g/L)
------------------------------------------------------------------------
Cadmium 1 2....................         7440439  [e (0.9789 x
                                                  ln(hardness) - 3.866)]
                                                  x CF
                                                 Where CF = 1.136672 -
                                                  [(ln hardness) x
                                                  (0.041838)].
------------------------------------------------------------------------
\1\ The criterion for cadmium is expressed as the dissolved metal
  concentration.
\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). The default hardness concentrations from the
  applicable ecoregion in Table 2 of paragraph (c) of this section shall
  be used to calculate cadmium criteria in the absence of sufficiently
  representative ambient hardness data.
\3\ The CMC is the highest allowable one-hour average instream
  concentration of cadmium. The CMC is not to be exceeded more than once
  every three years. The CMC is rounded to two significant figures.

    (c) Estimated Values To Calculate Cadmium Criteria. The default 
inputs to calculate cadmium criteria in the absence of sufficiently 
representative ambient data are shown in Table 2.

  Table 2--Hardness Defaults Within Each Level III Ecoregion in Oregon
------------------------------------------------------------------------
                                                               Hardness
                     Level III ecoregion                        (mg/L)
------------------------------------------------------------------------
1 Coast Range...............................................       34.12
3 Willamette Valley.........................................       32.39
4 Cascades..................................................       28.39

[[Page 9174]]

 
9 Eastern Cascades Slopes and Foothills.....................       36.08
10 Columbia Plateau.........................................       58.82
11 Blue Mountains...........................................       43.49
12 Snake River Plain........................................       123.5
78 Klamath Mountains........................................       40.61
80 Northern Basin and Range.................................       98.62
------------------------------------------------------------------------

    (d) Applicability. (1) The criterion in paragraph (b) of this 
section applies to freshwaters in Oregon where fish and aquatic life 
are a designated use, and applies concurrently with other applicable 
water quality criteria.
    (2) The criterion established in this section is 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 criterion applies at the appropriate locations within 
or at the boundary of the mixing zones and outside of the mixing zones; 
otherwise the criterion applies throughout the water body including at 
the end of any discharge pipe, conveyance or other discharge point 
within the water body.
    (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 Quality-Based Effluent Limitations 
in National Pollutant Discharge Elimination System permits:

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

[FR Doc. 2017-02283 Filed 2-2-17; 8:45 am]
BILLING CODE 6560-50-P