Mercury is an element that has many uses. It is also a potent nerve toxin that can impair the way we see, hear, walk, talk, and think.
Because it is an element, mercury never breaks down. It evaporates readily and travels long distances in the atmosphere, causing local, regional and global pollution. Worse, the amount of mercury being deposited from the atmosphere today is 3 to 4 times as much as was deposited 150 years ago.
Sources of mercury
About 30% of mercury in the atmosphere comes from natural sources such as volcanoes or forest fires. But 70% of the mercury is a result of human activities, including the mining of mercury ores, the use of this mercury in products and manufacturing, and the incidental release of trace concentrations of mercury naturally present in limestone, coal, crude oil, and metal ores such as taconite.
The good news is that total mercury emissions in Minnesota have declined significantly. In 1990, emissions are estimated to have been 11,272 pounds. By 2000, estimated emissions were just 3,638 pounds, a reduction of 68%, mostly due to discontinued use of mercury in many products and mandated controls on the incineration of solid waste.
Effects on humans and wildlife
When mercury is deposited in lakes or waterways, bacteria convert it to methyl mercury. Methyl mercury accumulates in algae and is eaten by smaller fish, which in turn are eaten by larger fish. Fish at the top of the aquatic food chain, such as walleye, can have methyl mercury concentrations as high as 130,000 times that of the surrounding water.
Unfortunately, the mercury in fish also concentrates in the tissue of any human or wildlife eating the fish. If contaminated fish are eaten on a regular basis, mercury concentrations can become high enough to become a serious health threat to humans. Several Great Lakes states issue advisories each year, cautioning people to limit the amount of fish they eat from area lakes.
Mercury gets into lakes from the atmosphere, where it falls with rain or snow into the watersheds that feed the lakes. Approximately one gram of mercury enters a 20-acre lake each year. Over time, just this small amount can contaminate the fish in that lake, making them unfit to eat on a regular basis.
Prevent mercury pollution
Each of us must do our part to keep mercury out of the environment. Make sure you buy mercury-free products whenever you can, such as mercury-free thermometers, heating/cooling thermostats, other types of switches and relays, and barometers and manometers. Make sure that you recycle mercury-containing products and bulk mercury; households can contact the local household hazardous waste collection program.
A few products require mercury to function, such as fluorescent and high-intensity-discharge lighting. These lights are still good choices environmentally and economically because they are highly energy efficient, which means they require less power generated by coal-burning power plants that release large amounts of mercury into the atmosphere. By using and then recycling these items properly, we can minimize overall releases of mercury to the environment from human activities.
Efforts by manufacturers of mercury-containing products, government programs, and solid waste management facilities have significantly reduced mercury entering the environment from products that contain it. For example, Hennepin County programs to keep mercury out of the waste stream, together with pollution control equipment on the county's waste-to-energy plant, have brought mercury emission levels down from 496 pounds in 1990 to less than 21 pounds in 2000, a reduction of over 95%.
Minnesota state statutes about mercury, updated through the 2006 legislative session; no mercury-related legislation has been enacted since the 2001 Legislature. The laws include guidance about proper disposal and efforts to reduce mercury contamination in Minnesota.
Minnesota Waste Management Act: Mercury laws as amended through the 2007 legislative session (last update October 2007)
Minnesota Auto Mercury Switch Recovery Program
In 2004, in partnership with Minnesota Waste Wise and vehicle manufacturers, the MPCA helped establish, promote, and evaluate a two-year program to collect and recycle vehicle mercury switches in Minnesota. The program targeted salvage yards, scrap processors, vehicle crushers, and related businesses. The Minnesota Mercury Recovery program built on nearly a decade of education and outreach to salvage yards through the MPCA, trade associations, and steel end markets.
Progress report. At the request of legislators, the Office of Environmental Assistance did a progress report on the program's implementation and switch recovery: Report on Implementation Progress of the Minnesota Auto Mercury Switch Recovery Program (May 2005)
In 2005, vehicle manufacturers established a national program for mercury switch collection and recycling, modeled in part on Minnesota's program: www.epa.gov/mercury/switch.htm. MPCA staff participated in the national negotiations as a member of the Environmental Council of States, along with the U.S. EPA, automobile manufacturers, steel manufacturers, environmental organizations, the national Automotive Recyclers Association, and the national Institute of Scrap Recycling Industries.
Minnesota's program continues, but it is now managed by this national program, coordinated by End of Life Vehicle Solutions Corporation.
Links to other resources
Minnesota fish advisories. Those who consume fish regularly should be concerned about mercury and other contaminants that may be present in Minnesota lakes. To help Minnesotans make educated choices about where to fish and what can be kept for eating, the state's Departments of Health and Natural Resources have teamed up to post fish consumption advisories online.
- Fish Consumption Advice from the Department of Health.
- DNR's Lake Finder contains data for more than 4,500 lakes and rivers throughout Minnesota, including fish consumption advice by lake.
U.S./Canada Bi-National Strategy for Eliminating Mercury
Mercury in the environment is not just a concern in Minnesota, but internationally. The United States and Canada have joined together to develop this Bi-National Strategy for limiting mercury, as well as other toxic chemicals, in our environment.
Western Lake Superior Sanitary District (WLSSD)
Efforts to reduce mercury in the environment are also taking place at the local level, especially in the Great Lakes area, and WLSSD in Duluth has led the way. In March 2000, Duluth was the first city in the country to ban the retail sale of mercury fever thermometers. WLSSD developed many resources: Blueprint for Mercury Elimination (2004) is a guidance document designed for wastewater treatment plants seeking to reduce mercury; "Mercury, Get Mad Now, Not Later" is a citizen's guide about mercury.
Health Care Without Harm
Because of its use in numerous medical devices, mercury is of particular concern to those in the health care field. Health Care Without Harm is a campaign for environmentally responsible health care that seeks to reduce pollution from health care practices.