RALEIGH, (SGRToday.com) - Proposed revisions to state surface water quality standards, including the numbers the state uses to evaluate metals, have been approved by the N.C. Environmental Management Commission in response to the federally-required Triennial Review of Surface Water Quality Standards. The approval was announced by the state Department of Environment and Natural Resources.

The federal Clean Water Act requires states to periodically evaluate surface water standards in light of recent research and information about water pollutants’ effects on aquatic life and human health.

The new standards are in line with nationally recommended water quality guidance and change how the state measures environmental impacts of certain metals. It includes changing some standards from total recoverable metal concentrations to dissolved metal concentrations where measuring dissolved metal concentrations more accurately describes the portion of the metal that is toxic to aquatic life. Additionally, the state will take into account the effect that water hardness has on the toxicity of metals. These modifications will affect how the standards are sampled, reported and incorporated into permits for industrial and wastewater treatment discharges.  

The changes will not take effect until after the EPA does a final review and approval of the state’s standards.