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A toxic compound requiring proper disposal

Mercury is highly toxic, and we need everyone’s help to keep this pollutant out of water and wastewater.

Mercury can be found in many old products and even some new ones. But the compound can cause serious health issues and damage the nervous, digestive and immune systems. This makes proper disposal essential for public health and the environment.

When it gets into the water, it accumulates in the bodies of fish. As smaller fish get eaten by larger fish or other wildlife up the food chain, the compound bioaccumulates, meaning the larger body takes on the contaminants present in its food. This is particularly problematic for individuals and groups who rely on subsistence fishing, as it makes them more vulnerable to this type of poisoning.

To protect our local streams and public health, our wastewater treatment plant is subject to very stringent limitations on the amount of mercury present in our treated effluent. This limit helps minimize the amount reaching fish, wildlife and humans.

What you can do

Familiarize yourself with common mercury-containing products.

  • Determine whether you have any in your house and replace with less-toxic (and readily-available) alternatives. A few common places to look include:
    • Medicine cabinets: Thermometers, blood pressure cuffs, contact lens solution (look for thimerosal as an ingredient)
    • Walls: Thermostats, barometers, silent switches
    • Lights: Fluorescent lamps, metal halide lamps
  • Dispose of the products safely at a disposal site. Dane County Clean Sweep accepts many types of household waste.
  • Replace the products with pollutant-free alternatives. The Wisconsin Department of Natural Resources (WDNR) has a list of alternatives to common products.
  • Follow safe clean-up procedures in the event of a spill.

Dental mercury reduction

The District works with dental clinics to continue successful pollution prevention initiatives. Dental amalgam – commonly known as “silver fillings” – contains mercury. When these fillings are placed or removed, the amalgam particles enter the sewer system and are a source of pollution to the treatment plant.

Dental clinics have been valuable partners in the District’s pollution reduction efforts, implementing practices and installing devices that capture amalgam and reduce mercury discharges to the sewer. These efforts have resulted in a decrease in mercury reaching the treatment plant and leaving in the treated effluent.

Additional Resources

U.S. EPA – Mercury

The U.S. Environmental Protection Agency (EPA) offers a comprehensive educational resource.

WDNR – Mercury

Find mercury information specific to Wisconsin, including fish consumption advice and details on the state ban.

WDNR – Lightbulb recycling

See WDNR information and resources to properly dispose of lightbulbs and ways to find a recycler near you.

2023 PMP Report

Review the District’s Pollution Mitigation Plan (PMP) and Source Reduction Report for Mercury.