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Mercury Minimization

  • The City works with businesses and dental practices to keep mercury out of wastewater.

    Mercury minimization 

    Gresham’s methods for reducing environmental impacts of mercury include:

    • Policies and code for residential and commercial customers.
    • Required permits for industrial dischargers.
    • Implementation of mercury reduction best practices at City-owned buildings and infrastructure. 

    Dental Waste Management 

    The City's Mercury Minimization Plan includes requirements for dental practices to control the discharge of amalgam and other metals into the wastewater system.

    • Dental amalgam is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper which is used to fill cavities in teeth.
    • Mercury and other metals can have a wide range of harmful effects on human and aquatic life once released into the aquatic environment.
    • The City’s wastewater treatment plant is not designed to remove toxic metal pollutants in waste streams before release into the Columbia River.

    Dental Waste Management Program requirements

    • Operate and maintain amalgam separators according to manufacturer recommendations, and do not discharge scrap amalgam into the wastewater system or use certain kinds of line cleaners.
    • Control the discharge of amalgam and other metals into the wastewater system.
    • Maintain records for three years of the handling and disposal of amalgam, maintenance and service of amalgam separators, and also keep records of x-ray fixer recycling.
    • Follow the Oregon Dental Association’s Best Management Practices of Dental Waste.
    • Each year by Jan. 31, complete and sign a Certification of Compliance Statement with the City of Gresham.  

     Annual certification statements due by Jan. 31

      Annual Certification of Compliance statement 

    On behalf of the US Environmental Protection Agency, the City accepts and maintains records on dental practices’ federal One-Time Compliance Report. 

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