United States
Environmental Protection
  Office of Water
     July 2016
Fact Sheet: Draft Estuarine/Marine  Copper
Aquatic  Life Ambient Water Quality Criteria
EPA has issued for public comment draft aquatic life
criteria for copper in estuarine/marine waters. The
2016 draft criteria incorporate a recently-developed
saltwater biotic ligand model (BLM) and the latest
scientific information for estuarine/marine aquatic
organisms. The BLM allows users to develop
protective chronic and acute values based on site-
specific water quality variables including
temperature, dissolved organic carbon (DOC),
salinity, and pH, which influence the bioavailability
and toxicity of copper in estuarine/marine
The updated criteria will be particularly beneficial in
the adoption of water quality standards for the
protection of aquatic life in and around coastal
harbors and marinas, where antifouling paints and
coatings on vessels and marine structures represent
one of the most commonly identified sources of
copper to the estuarine/marine environment.
The draft criteria underwent independent,  external
peer review in 2015. EPA will accept comments on
the 2016 draft criteria document for 60 days upon
Federal Register publication.

In 2007, EPA published updated aquatic life criteria
for copper in freshwater using a BLM, a model that
relies on water quality input parameters to estimate
the fraction of copper that is bioavailable and thus
can exert a toxic effect. Estuarine/marine criteria
were not updated in that publication because a BLM
for estuarine/marine waters had not been
sufficiently developed and tested at that time.
                            What is Copper?
                            Copper is an abundant trace element that occurs
                            naturally in the earth's crust and surface waters.
                            Copper can be found as a pure metal in nature and
                            has a high thermal and electrical conductivity.
                            Copper compounds are generally found in water as
                            copper (II) salts.
                            How Does Copper Enter Marine/Estuarine
                            Copper is commonly found  in aquatic systems as a
                            result of both natural and anthropogenic sources.
                            Natural sources of copper in aquatic systems include
                            geological deposits, volcanic activity, and weathering
                            and erosion of rocks and soils. Anthropogenic
                            sources of copper include mining activities,
                            agriculture, metal and electrical manufacturing,
                            sludge from publicly-owned treatment works
                            (POTWs), pesticide use and more. A major source of
                            copper in the marine environment is antifouling
                            paints,  used as coatings for ship hulls, buoys, and
                            underwater surfaces, and as a legacy contaminant
                            from decking, pilings and some marine structures
                            that used chromated copper arsenate (CCA) treated
                            How Does Copper in Saltwater Affect Aquatic
                            Copper is an essential nutrient to aquatic organisms
                            at low concentrations, but is toxic to aquatic
                            organisms at higher concentrations. In addition to
                            acute effects such as mortality, chronic exposure to
                            copper can lead to adverse  effects on survival,
                            growth, reproduction as well as alterations of brain

function, enzyme activity, blood chemistry, and
metabolism in aquatic organisms.
How Do the  Draft 2016 Criteria Compare to the
2003 Draft Criteria?
New acute toxicity data for estuarine/marine species
have been included in  EPA's 2016 update. A total of
74 genera are used to  derive the estuarine/marine
criterion maximum concentration (CMC) in the 2016
update compared to the 44 genera used in EPA's
2003 draft estuarine/marine criteria for copper. The
2016 update uses the BLM to incorporate the
interaction  and effect of physical and chemical water
parameters (pH, temperature, salinity and DOC) that
affect the bioavailability of copper to aquatic
organisms.  Incorporation of the BLM accounts for
copper bioavailability in natural aquatic systems, in
contrast to  the 2003 draft criteria which did not
account for the interactions of these parameters on
copper bioavailability and their effect on copper
Table 1  below gives an example of what the draft
2016 water quality criteria are for waters with the
following default reference conditions:
Temperature=22C, pH=8, Dissolved Organic
Carbon=1.0 mg/Land Salinity=32 ppt.
Table 1. Example of Draft Estuarine/Marine Criteria
for Copper  Using Default Reference Conditions.
(1-hour average)
2.0 u.g/L dissolved Cu
(4-day average)
1.3 u.g/L dissolved Cu
aWhen Temperature=22C, pH=8, Dissolved Organic
 Carbon=1.0 mg/L and Salinity=32 ppt. The water quality
 criteria numeric values will change in response to changes in
 these water quality parameters.
b Values are recommended not to be exceeded more than once
 every three years on average.
What are National Recommended Aquatic Life
Ambient water quality criteria for the protection of
aquatic life are numeric concentrations of pollutants,
with specific recommendations on the duration and
frequency of those concentrations, in surface waters
that are protective of aquatic life designated uses.
Under Clean Water Act section 304(a), EPA is
directed to develop and publish water quality
criteria that reflect the latest scientific knowledge.
Water quality criteria are based solely on data and
scientific judgments about the relationship between
pollutant concentrations and potential
environmental and human health effects. EPA's
recommended water quality criteria are not rules,
nor do they automatically become part of a state's
water quality standards. States must adopt into their
standards water quality criteria that protect the
designated uses of the water bodies within their
area. These can include scientifically defensible site-
specific criteria that are different from EPA's national
recommended criteria, as long as the site-specific
criteria are protective of the designated use. Water
quality criteria are not effective under the Clean
Water Act until they have been adopted into a
state's water quality standards and approved by
How to View the Criteria Document and
Supporting Information:
EPA has established an official public docket for this
action under Docket ID No. EPA-HQ-OW-2016-0332,
accessed at www.regulations.gov. You may also
download the document and supporting information
from EPA's aquatic life criteria website at:
Where can I find more information?
Please contact Mike Elias by email at