Aquatic Life Criteria - Copper

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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 as copper (II) salts.

How does copper enter surface water?

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 contaminant from decking, pilings and some marine structures that used chromated copper arsenate (CCA) treated timbers.

How does copper affect aquatic life?

Copper is an essential nutrient 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.

2016 Draft Estuarine/Marine Copper Aquatic Life Ambient Water Quality Criteria

The draft criteria was released on July 29, 2016 for a 60 day public comment period. The draft document incorporates use of the saltwater biotic ligand model (BLM), a bioavailability model that relies on water quality input parameters to estimate copper criteria that is protective of aquatic life in estuarine/marine environments, and an updated toxicity database. Incorporation of the BLM allows users to account for individual water quality variables (temperature, pH, dissolved organic carbon, and salinity) that influence the bioavailability and toxicity of copper in estuarine/marine environments.

2007 Freshwater Copper Criteria Update

EPA issued a revised national recommended freshwater aquatic life criterion for copper (Aquatic Life Ambient Freshwater Quality Criteria—Copper 2007 Revision). As a companion to the criteria document, EPA has also released documents to supplement training materials and help states, tribes, permittees, and other interested stakeholders on implementing the nationally recommended criteria.

2003 Draft Copper Criteria Update

EPA has published a draft document, 2003 Draft Update of Ambient Water Quality Criteria for Copper (EPA-822-R-03-026), containing updated freshwater and saltwater aquatic life criteria for copper. These criteria revisions are based in part on new data that have become available since EPA's last comprehensive criteria updates for copper. In addition to incorporating new data, the freshwater criteria also incorporate the use of the biotic ligand model (BLM) in the criteria derivation procedures.

Related Technical Documents

Draft Technical Support Document: Recommended Estimates for Missing Water Quality Parameters for BLM

This draft technical support document provides recommendations for default values for water quality parameters that can be used in the Freshwater Copper BLM when data are lacking. The document also describes data analysis approaches used to develop these recommendations. Following closure of the public comment period on April 18, 2016, EPA will consider the comments, revise the document, as appropriate, and then publish a final technical support document that will serve as a source of information for states, tribes, territories, and other stakeholders.

Copper BLM Workshop Proceedings

In May of 2015, EPA hosted a workshop for federal agencies, Pacific Northwest states, academics, and the private sector to discuss lessons learned from implementing the BLM and approaches to adopting BLM-based criteria. The two-day workshop included overview presentations of the model, discussions among states on experiences and anticipated challenges, and discussions of implementation considerations.

Streamlined Water-Effect Ratio Procedure for Discharges of Copper

This document presents a Streamlined Procedure for determining site-specific values for a Water-Effect Ratio (WER), a criteria adjustment factor accounting for the effect of site-specific water characteristics on pollutant bioavailability and toxicity to aquatic life. This procedure is only recommended for copper and in situations where copper concentrations are elevated primarily by continuous point source effluents.

The document is intended to complement the 1994 Interim Guidance on Determination and Use of Water-Effect Ratios for Metals (EPA-823-B-94-001). The design of the Streamlined Procedure is intended as a more efficient approach for generating the information needed to make a pollution control decision.

Document: Streamlined Water-Effect Ratio Procedure for Discharges of Copper (March 2001)

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