Mercury Reduction

Mercury is a hazardous material that causes serious environmental and health problems. Although it is found naturally, problems arise from its release from human made products and energy production. Once mercury is released into the environment, it cycles and converts to the toxic form, methylmercury, and is virtually impossible to remove.

Mercury pollution in the Great Lakes states is a significant public health and economic issue. Mercury is a persistent, bio-accumulative pollutant. Due to its bio-accumulating effects, the water quality criteria for mercury are extremely low.

Preserving the water quality in the Milwaukee River is essential to the Saukville area's economy and quality of life. The Saukville Wastewater Treatment Plant (WWTP) plays a vital role in protecting the water quality of the Milwaukee River. However, current wastewater treatment processes cannot remove sufficient mercury to meet the exceptionally low river water quality standard of 1.3 ng/L of mercury. The wastewater treatment processes required to remove mercury to these ultra low levels would be prohibitively expensive to build and operate.

The Wisconsin DNR has recognized these expenses and has required the Saukville WWTP  to implement a Mercury Pollutant Minimization Plan (PMP). The mercury PMP focuses on the discharges to the WWTP from the sectors which have historically used and/or continue to use mercury containing products in their day to day processes which can impact wastewater discharges.


Common Sources of Mercury in DOMESTIC PRODUCTS (from Wisconsin DNR website)

Switches- mercury used as an electrical conductor in a varitety of switches.

Common Sources
  • Thermostats / non-digital thermostats - usually round, contain 3-6 grams of mercury.
  • Wall light switches that were silent and manufactured before 1991
  • Chest freezer lights and automobile hood and truck lights
  • Irons / Space Heaters- safety shut-off switch in case the iron or space heater falls over
  • Washing machine - safety shut-off switch under the lid so the spin cycle stops when the lid opens
  • Outboard motor - safety shut-off
  • Lap-top computer - screen shuts off when closed
  • Sump pumps / Septic systems - floater switch to turn on pumps when water reaches certain levels
  • Lawn mower - fuel level indicator
  • Security systems - switch used to activate alarm when movement is sensed
  • Phones - mute switch when phone is a horizontal position
  • Thermometers - mercury used in fever, basal, weather, and candy/deep fry thermometers
*** Use alcohol or digital thermometers instead. ***
Lights - mercury used in fluorescent lights, neon lights (window advertising), high pressure sodium vapor lights (outdoor security and street lighting), high intensity discharge lights (headlights). Fluorescent lights are very energy and cost efficient so they should still be used and then recycled at end of their life cycle.
  • Button batteries - small amount of mercury contained in mercuric oxide, silver oxide, and zinc air button batteries which are used in watches, hearing aids, toys, and other devices requiring small batteries.
  • Cylindrical and rectangular cell batteries - alkaline batteries sold before 1996 and zinc carbon batteries sold before 1994 contain mercury
  • Old ovens, water heaters, furnaces - thermostat probe, which opens and closes the gas-control valve, used as a safety feature in gas-fired appliance
Agricultural chemicals/lawn chemicals/latex paint/wood treatment - mercury used as a pesticide, fungicide, or mildewcide. Use of mercury in latex paint was banned in 1991 and in the other products by 1995.
Contact lens solutions (thimerosal), nasal sprays, diuretics, disinfectants, eye cosmetics - mercury used as a perspective

Cameras - position sensor used in still, video, and film cameras to protect CCD from sunlight

Light-up shoes - switch