oEPA
Office of Water
United States	EPA820-F-17-001
Environmental Protection	January2017
Agency
Fact Sheet: Final Aquatic Life Water
Quality Criterion for Cadmium in Oregon
Summary
EPA has finalized a rule that establishes an acute
cadmium aquatic life criterion for freshwaters under
Oregon's jurisdiction. EPA has established this
criterion to protect aquatic life from adverse effects
of exposure to harmful levels of cadmium.
Background
Clean Water Act (CWA) section 101(a)(2) establishes
the national goal that water quality should provide
for the protection and propagation of fish, shellfish,
and wildlife, and recreation in and on the water. To
protect aquatic communities from the harmful
effects of pollutants in surface waters, states must
establish aquatic life criteria for their waters that are
designated forsuch uses. EPA periodically publishes
criteria recommendations under CWA section 304(a)
for states to consider using to meet these CWA
section 101(a)(2) goals.
On January 31, 2013, EPA determined that Oregon's
2004 acute freshwater cadmium criterion did not
meet CWA requirements to protect aquatic life in
the state, and disapproved the criterion. Oregon did
not adopt a revised acute cadmium criterion;
therefore, to protect freshwater aquatic life in
Oregon from the adverse effects of cadmium, EPA
has finalized the criterion in this rule using the best
available science on cadmium toxicity.
How EPA Derived the Final Acute Cadmium
Aquatic Life Criterion
In 2016, EPA published revised CWA section 304(a)
recommended criteria for cadmium, based on the
latest science on cadmium toxicity. Ambient water
hardness (determined by the presence of calcium
and magnesium ions) affects the toxicity of
cadmium, such that organisms show more sensitivity
to cadmium in water with lower hardness. EPA's
freshwater CWA section 304(a) recommended
cadmium criteria are equations to calculate
protective cadmium criteria based on the relevant
water body's hardness. EPA's April 2016 proposed
rule, as well as EPA's final rule, used the updated
CWA section 304(a) recommended acute cadmium
criterion equation to protect freshwater aquatic life
in Oregon. EPA also promulgated protective default
hardness values in the final rule, for Oregon to use in
the acute cadmium criterion equation when
sufficient representative data to determine the
water body's hardness are not available.
How EPA's Final Rule Relates to Oregon's
Rulemaking Efforts
EPA's April 2016 proposed rule also included
freshwater aquatic life copper criteria to remedy
EPA's January 2013 disapproval of Oregon's 2004
copper criteria. However, Oregon engaged in its own
rulemaking process to develop copper criteria that
protect freshwater aquatic life, and submitted
revised freshwater acute and chronic copper criteria
to EPA for review on November 14, 2016. In parallel
with this final rule, EPA has approved the freshwater
copper aquatic life criteria submitted by Oregon and
these criteria are effective for CWA purposes.
Therefore, EPA did not finalize copper criteria in the
federal rule. Similarly, If Oregon adopts and submits
a new or revised acute cadmium criterion that EPA

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finds meet CWA requirements, and EPA approves
such criteria, EPA would expeditiously undertake a
rulemaking to withdraw the federal acute cadmium
criterion such that Oregon's criterion would be solely
effective for CWA purposes.
Where can I find more information?
Contact Erica Fleisig at (202) 566-1057,
fleisig.erica@epa.gov or Rochelle Labiosa at (206)
553-1172, labiosa.rochelle@epa.gov. To access the
final rule, visit EPA's Water Quality Standards
website at: http://www.epa.gov/wqs-tech/water-
quality-standards-regulations-oregon.

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