March 26, 2021
BOISE — The Idaho Department of Environmental Quality seeks comment on additions to the Implementation Guidance for the Idaho Copper Criteria for Aquatic Life.
The additions, found in Section 6.2 of the document, clarify how DEQ will apply superseding copper criteria in discharge permits.
Copper is a naturally occurring element in the earth’s crust and is an essential micronutrient for plants, animals, and humans. However, at concentrations above the recommended levels, copper can become acutely toxic, especially to aquatic organisms.
The purpose of this document is to provide background on copper toxicity and the biotic ligand model and provide guidance to DEQ staff, the regulated community, and the general public for calculating the copper criteria for aquatic life using the biotic ligand model.
It also discusses data requirements, spatial and temporal representation, options for reconciling multiple time-variable criteria from a single location, and procedures for estimating criteria when data are limited.
The Implementation Guidance for the Idaho Copper Criteria for Aquatic Life is available for public review at DEQ’s State Office (1410 N. Hilton St.) and on DEQ’s website.
Written comments must pertain to Section 6.2 of the report. Comments will be accepted through April 26, 2021, at 5 p.m. MST, and can be submitted electronically on DEQ’s Public Comments page or by mail or email to:
Surface Water Bureau Chief
1410 N. Hilton
Boise, ID 83706