Recent published scientific information indicates that discharges from mountaintop mining and valley-fill operations in Southern Appalachia may be linked to degraded water quality and adverse impacts on in-stream biota. Discharges from surface coal mining, valley-fills and associated operations are regulated under the Clean Water Act (CWA) and under the Surface Mining Control and Reclamation Act of 1977 (SMCRA). Under the CWA, discharges from mountaintop mining and valley-fill operations require an NPDES permit that either meets technology-based effluent limits or water quality-based limits that are developed from ambient water quality criteria. Ambient Water Quality Criteria are developed for specific pollutants, and their application takes into account the conditions of a waterbody that are designed to protect the designated uses of the waterbody.
EPA’s ORD has developed a report that uses field data to derive an aquatic life advisory value for conductivity (a measure of salinity) that may be applied to waters in the Appalachian Region that are dominated by salts of sulfate and carbonate ions. This advisory value is intended to protect the biological integrity of waters in the region. It is derived by a method modeled on EPA’s standard methodology for deriving water quality criteria. In particular, the methodology was adapted for use of field data. ORD is requesting the SAB to peer review this draft conductivity document.