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Toxic Mercury Rains in Midwest

full NWF report
(ENS) CHICAGO -- A new report reveals that the rain and snow falling on cities in the American Midwest contains levels of mercury that far exceed what the U.S. Environmental Protection Agency (EPA) considers safe. The National Wildlife Federation and 21 state and local partner organizations are launching a Clean the Rain Campaign today to help reduce the health risks from toxic mercury.

The report by the National Wildlife Federation (NWF) compares mercury contamination levels in rain to EPA safe levels for human health in 20 Midwestern cities and towns. Among the report's findings are mercury levels in rain over Chicago, Illinois that are as high as 42 times EPA safe levels; Detroit, Michigan rain with 65 times safe levels; and rain along the Illinois/Wisconsin border as high as 56 times safe levels.

"We usually think of rain as pure and clean, and that's the way it should be," said Mark Van Putten, president & CEO of the National Wildlife Federation. "But this report reveals that rain falling over Midwestern cities such as Detroit, Chicago and Duluth contains as much as 65 times the EPA ‘safe' level of mercury, which holds out extremely serious health implications for both humans and wildlife."

Mercury is a potent toxin. When ingested in even tiny amounts can cause devastating effects on the human nervous system, especially for children and the unborn. Associated illnesses include brain, lung and kidney damage and even death in humans. In wildlife, mercury is a reproductive hazard that can cause harmful effects on species such as frogs, rainbow trout, zebra fish, mallard and American black ducks, loons and terns.

"With so much at stake for both people and wildlife, decisive action is needed right now to limit mercury emissions, because once mercury pollution goes up into the atmosphere, rain carries it right back down into the very water humans and wildlife depend on," said Peter Morman, of the Environmental Law and Policy Center.

"A drop of mercury as small as 1/70th of a teaspoon can contaminate a 25 acre lake"
The report is based on scattered monitoring of rain from various Midwestern sources. In Chicago, the University of Michigan Air Quality Laboratory collected 65 samples of rainwater from the Illinois Institute of Technology campus and measured mercury levels ranging from 5.4 parts per trillion to 74.5 parts per trillion. Average mercury levels were 12 times higher than EPA’s standard, and even the lowest level measured was more than four times higher than EPA safe levels.

"Nationally, more than a third of mercury emissions come from coal fired power plants, with the remainder coming from municipal waste incinerators and medical waste incinerators," said Morman. "In the Great Lakes region, coal combustion causes over half the mercury emissions."

Coal contains trace amounts of mercury that are released into the air as it is burned for energy. Rain droplets can form around tiny particles of smog and soot, including mercury contaminants, and carry them back to the earth.

The technology to measure the traces of mercury captured by raindrops has only existed since the mid-1990s.

There are currently no limits on how much mercury coal burning power plants can emit, but the EPA is studying mercury pollution from the plants with an eye to setting limits.

When medical devices such as thermometers and blood pressure cuffs or household items like fluorescent lights, lamps and thermostats are discarded and burned, the residual mercury is emitted into the atmosphere.

"A drop of mercury as small as 1/70th of a teaspoon can contaminate a 25 acre lake to the point that the fish in it are unsafe to eat," said Beverly McClellan of the Lake Michigan Federation. "When you consider a typical 100 megawatt power plant emits about 25 pounds of mercury a year, the potential for tremendous ecological and human health problems becomes alarmingly clear."

The Clean the Rain Campaign calls on major industry to drastically reduce emissions and asks citizens to help cut mercury pollution by conserving energy, not purchasing consumer products that contain mercury, or if they do purchase them, disposing of them properly at EPA approved recycling centers.

The Campaign also calls on federal and state governments to more closely monitor mercury levels in rainfall. In several key locations, the National Wildlife Federation has pledged to pay for rain monitoring if governments fail to do so. Chicago, Cleveland, Detroit, Duluth and Gary, Indiana are the first cities that NWF has targeted for additional monitoring. NWF is working with the University of Michigan and the University of Minnesota to develop and implement rain monitoring programs. Monitoring for mercury in Chicago's rain ended in 1995, and has never been conducted in Gary.

"While the news of the danger raining down from our skies is alarming, much can be done at the local, state and national levels to reduce the risk," said Andy Buchsbaum, NWF's water quality projects manager. "State agencies and the U.S. EPA need to begin monitoring for mercury in rain in Chicago and Gary. We need to know what's in our rain."

© 1999 Environment News Service and reprinted with permission

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Albion Monitor October 18, 1999 (

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