DEQ has adopted a new copper water quality standard for protection of freshwater aquatic life.
The US EPA Approved revisions to Oregon’s Aquatic Life Water Quality Standards for Copper on Jan. 9, 2017. The Oregon Environmental Quality Commission adopted the new rules on Nov. 2, 2016.
The revisions address EPA’s Jan. 31, 2013 disapproval of Oregon's freshwater copper criteria that the Oregon Environmental Quality Commission adopted in 2004. Copper is a pollutant that can cause adverse effects to salmon, trout and other aquatic species.
The updated copper criteria protects aquatic life based on EPA's latest 2007 national recommendations for copper. These criteria would generally apply to all freshwaters of the state.
EPA's recommendations for copper derive site-specific criteria using the Biotic Ligand Model. This model requires inclusion of 11 different water quality parameters that affect the bioavailability and toxicity of copper in freshwaters. Many studies show that this model is a better predictor of copper toxicity than water hardness alone.
Copper standard implementation
The toxicity of copper varies in aquatic environments because the bioavailability of copper changes based on water chemistry conditions. The Biotic Ligand Model determines copper toxicity for a given set of conditions by using measurements of ten different water quality parameters that affect copper toxicity to aquatic organisms. These parameters are pH, dissolved organic carbon (DOC), temperature, calcium, magnesium, sodium, potassium, sulfate, chloride, and alkalinity. The Biotic Ligand Model provides site-specific acute and chronic copper criteria that reflect changes to copper bioavailability caused by interaction with these water chemistry variables. Using the BLM provides a high degree of protection to aquatic life during vulnerable water chemistry conditions and will also identify those conditions that are less sensitive, where toxicity occurs at greater copper concentrations.
Rulemaking process and documents
Environmental Quality Commission action and staff report
- The EQC adopted the proposed rules on Nov. 2, 2016.
- EQC Staff Report Item G (includes adopted rules and summary of public comment received)
EPA and National Marine Fisheries Service Communication on Copper