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Special Initiatives - NACWA Mercury Initiatives Print E-mail

Many wastewater treatment facilities are, or soon will be, faced with very low mercury effluent limits due to the application of stringent water quality criteria. New analytical methods and sampling techniques are enabling clean water facilities to measure levels of mercury that were previously undetectable. Because of the U.S. Environmental Protection Agency’s (EPA) new human health criterion for methylmercury in fish tissue and the increasing number of fish advisories based on mercury, there are few parts of the country that will remain unaffected. Wastewater treatment agencies are concerned that compliance will require the application of costly advanced treatment that may not improve water quality.

  • While NACWA believes each community must make the decisions that are right for its citizens, the Association favors a national, holistic strategy that fairly and equitably takes into account the various sources of mercury – air, industrial, national and international.
  • The relative contribution of wastewater treatment plants and the existing and developing control strategies they are employing should be taken into consideration as total maximum daily loads and permit restrictions on the discharge of mercury are developed.

In an effort to increase its understanding of the issues surrounding mercury in the environment, NACWA has committed significant resources to conduct studies, develop papers, and facilitate national and global collaboration. This web page presents the results and recommendations from these projects in an effort to further collaboration on the complex issue.

Completed Projects, White Papers, and Reports

  • NEW – NACWA Mercury Sampling Project.  For this effort, the influent, effluent, and biosolids mercury concentrations from twelve U.S. and Canadian POTWs that were in various stages of requiring dental facilities to install amalgam separators were measured on a monthly basis from July 2003 through July 2006 to evaluate the impact of separator installation and other potential factors.  Information on other source control efforts and operational activities at the sampled POTWs was also collected in an effort to shed light on numerous issues related to controlling mercury releases by POTWs to the environment.

  • NACWA White Paper on the various control options available for minimizing mercury in wastewater discharges from dental clinics. This effort was designed to educate other communities and states that may be considering their options for controlling mercury discharges from dental clinics. NACWA’s members have learned a great deal through actual implementation of best management practices, numeric limits, and separator requirements for dentists, and our goal was to share those experiences with others.

NACWA also recognizes the importance of collaboration and encourages readers of this white paper to work closely with their state and local dental associations as they consider what is best for their community. A listing of state and local dental associations is available at: http://www.ada.org/ada/organizations/index.asp.

NACWA White Paper on Controlling Mercury in Wastewater Discharges from Dental Clinics (January 2006) (PDF, ~237 KB)