Source: NCDENR, 11/14/14

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 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.  

Also included in approval of the recommendations made during this standards review are:
•        Health protective water quality standards for 2,4-D, a widely used herbicide.
•        Updated aquatic life protective concentrations for arsenic, beryllium, cadmium, chromium III, chromium VI, copper, lead, nickel, silver and zinc.
•        Clarity on allowing site-specific standards to be developed when studies are done in accordance with guidance from the Environmental Protection Agency.

Two public hearings were held in July to gather information on the proposed changes. A report summarizing the issues reviewed and the comments received is available on the N.C. Environmental Management Commission’s website at: http://portal.ncdenr.org/web/emc/november-13-2014, Action Item 14-42, attachment A. 

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