Draft Field-Based Methods for Developing Aquatic Life Criteria for Specific Conductivity Documents

EPA has published a draft document, Field‑Based Methods for Developing Aquatic Life Criteria for Specific Conductivity. Elevated water salinity, as measured by conductivity, has been shown to negatively affect aquatic life in freshwaters. Elevated conductivity is associated with multiple sources, including discharge from wastewater treatment facilities, surface mining, oil and gas exploration, runoff from urban areas, and discharge of agricultural irrigation return waters. The draft methods provide flexible approaches for developing science-based conductivity criteria for flowing waters that reflect ecoregional- or state-specific factors. Once final, states and authorized tribes located in any region of the country may use the methods to develop field-based conductivity criteria for flowing waters. This draft document provides a scientific assessment of ecological effects and is not a regulation. On December 23, 2016, EPA announced the availability of the draft document and opened a 60-day public review and comment period to solicit scientific views, data, and other information. In response to stakeholder requests, the comment period will be extended for an additional 62 days, from February 21, 2017 to April 24, 2017.

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