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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.
    • Complete the one-time Federal Compliance Report
    • 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

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