Greatest Lakes in the World

But can they stay great and still help meet the needs of 60 million local residents, heavy industry, mining, shipping and a host of other interests?

  • Roger Di Silvestro
  • Jun 01, 2004

THE FIVE GREAT LAKES—Huron, Superior, Erie, Michigan and Ontario—compose the planet’s largest freshwater system. Covering 94,000 square miles, containing 5,500 cubic miles of water and bordered by 10,210 miles of shoreline, the lakes account for almost 20 percent of the world’s freshwater and more than 95 percent of surface freshwater for the Lower 48 states. Only the polar ice caps contain more freshwater.

The greatest of the lakes is Superior. With a volume of 2,900 cubic miles, it could hold all the other Great Lakes plus three more Lake Eries, or cover all of North America under 1 foot of water if spread out over the continent.

Development has made the Great Lakes Basin, the 308,000-square-mile area in which all water eventually flows into the lakes, one of the population centers and regional industrial leaders of both the United States and Canada. Home to more than 30 million people, the basin produces 60 percent of North America’s steel and cars. The Great Lakes fishery is worth up to $4 billion annually to the United States and Canada. Regional production came to almost $2 trillion in 2000, exceeding the gross domestic production of all nations except the United States and Japan.

A WATERFALL (right page, top) tumbles into Lake Superior, bringing with it the history of its travels across surrounding lands, including toxic substances encountered along the way. Industries like this taconite plant (right page, bottom left) north of Duluth, Minnesota, contribute to Great Lakes pollution, posing a threat to area residents as well as to wildlife, such as this bald eagle (right page, bottom right) perched along a Superior shore.

Industry, commerce and development have heavily taxed the health of the lakes, posing complex problems that are not easy to solve. Eight states and the Canadian province of Ontario surround the Great Lakes, so regional protection requires cooperation among many governments and will demand a massive effort rivaling in size the state and federal plan to save the Everglades. The following pages look at the issues and problems that Great Lakes communities face in attempting to protect this massive watershed.

Putting National Treasures at Risk
Some 300 toxic chemicals occur in the Great Lakes, including lead, cyanide, arsenic, PCBs, dioxins and pesticides. Pollutants reach the Great Lakes through a variety of pathways, including runoff from land and seepage through groundwater. The wind may be the single largest source of Great Lakes pollutants, carrying in, for example, as much as 80 percent of the basin’s PCBs. Pollutants can blow in from hundreds of miles away, but about two thirds of the mercury falling into Lake Michigan is produced in the basin.

One of the biggest pollution threats of the moment is a proposed U.S. Army Corps of Engineers plan to boost dredging operations for harbors and shipping channels everywhere from Ohio’s Toledo Harbor to Detroit’s River Rouge to the port at Gary, Indiana, increasing the amount of dredged silt by 167 million cubic yards yearly. About 40 percent of the dredged silt, loaded with motor oil, PCBs, heavy metals and other toxic chemicals, will be buried in landfills. The rest will be dumped elsewhere in the Great Lakes. "Dredging contaminated silt is devastating to wildlife habitat," says Tim Eder, who heads NWF efforts to reform the Corps.

The lake trout is a good example of how toxic substances have damaged the Great Lakes ecosystem. As long ago as the 1870s, fishermen were taking more than a million pounds of lake trout yearly from Lake Ontario, which is biologically the least productive of the lakes. In the 1890s, Lake Huron was yielding 7.5 million pounds yearly and Lake Michigan about 3 million. That level of catch, along with habitat destruction and competition from invasive species, led to a collapse of the lake trout. By the early 1960s, the species was extinct in lakes Michigan and Ontario and nearly so in Huron. In the mid 1960s, the federal government began spending millions of dollars to restore the lake trout, releasing millions of the fish yearly. But only a few of them spawned successfully. Federal researchers soon ascertained that a witch’s brew of toxic chemicals in the tissues of adult lake trout were making their way into the yolks of lake trout eggs. Result: In most cases, the eggs did not hatch, and when they did, the young fish suffered from developmental defects that caused them to swim erratically and, finally, to die.

Urban waste is yet another problem. For example, last December United Water Services, a private contractor that handles sewage for Milwaukee, legally dumped 40 million gallons of partially treated sewage into Lake Michigan. Such urban dumping increases risks of bacterial contamination and contributed to the closing of nearly 900 Great Lakes beaches in 2002. "Nothing signals the need for better protection of the Great Lakes than the fact that this vast system had become polluted to the point of threatening human health," says Neil Kagan, who works on water pollution issues for the NWF Great Lakes office.

Studies since the 1980s indicate that children whose mothers regularly ate fish from Lake Michigan during pregnancy tend to show signs of harm to short-term memory and generally are smaller and less responsive than children of mothers who did not eat the fish. The affected children perform within normal ranges for their age but do not attain the higher levels of performance they could have reached without fetal exposure to toxics. Accumulating evidence suggests that one particularly toxic pollutant, mercury, also harms adults, increasing blood pressure, contributing to heart disease and causing impaired vision and hearing as well as damage to the nervous system. Such threats to human health resulted in 1,820 state warnings in 2002 recommending dietary restrictions for Great Lakes fish.

THE BLACK BEAR (right page, left) is among native species with habitat along Lake Superior shores jeopardized by a potential underground mine near Big Bay, Michigan. A lighthouse (right page, top right) on Lake Ontario bespeaks the region’s long history in the shipping industry. On the Illinois River, biologists examine bighead carp (right page, bottom right), an Asian species that is threatening to move up nearby rivers into the Great Lakes.

On the bright side, recent research suggests that federal bans on DDT and PCBs, dating to the 1970s, significantly reduced toxic contamination in the Great Lakes area as evidenced by declines in PCB and DDE (a metabolite of DDT) contamination in Great Lakes bald eagles. Among eagles in Michigan’s Upper Peninsula, PCB blood levels dropped from 26 parts per billion (ppb) to 4 ppb between the late 1980s and 2000, says Bill Bowerman, of Clemson University, who has been studying eagles since the 1980s. At Lake Superior, they dropped from 127 to 16 ppb. DDE in the Upper Peninsula dropped from 10 to 4 ppb, and at Lake Superior from 25 to 13 ppb, Bowman says.

Seeking Solutions to Pollution 
Mercury is one of the most dangerous of Great Lakes contaminants. When it enters aquatic systems, mercury goes through chemical reactions that render it into a highly toxic form, methylmercury. A seventieth of a teaspoon is enough to contaminate the fish of a 25-acre lake. Mercury pollution comes from dental offices and other sources, but the primary source is air pollution from coal-fired power plants, which can travel for hundreds of miles.

Forty-three states have issued mercury fish-consumption advisories, including all the Great Lakes states, affecting the region’s multibillion-dollar recreational fishing industry in addition to human and wildlife health. "While it’s important to heed fish advisories, the only real solution is to eliminate the sources of mercury pollution," says Zoe Lipman, who works on air pollution issues at NWF’s Great Lakes office. Coal-fired power plants have the technology to cut mercury emissions up to 90 percent, she adds, but the Bush administration nevertheless has proposed measures that would slow mercury cleanup under the federal Clean Air Act. Across the Great Lakes region, however, communities and state agencies are looking at ways to reduce mercury pollution dramatically.

One such attempt concerns mercury not as an air pollutant but as a water contaminant. Duluth, Minnesota, on the western shore of Lake Superior, is taking the lead in stemming key sources of contamination by keeping mercury out of city wastewater, says Joe Stepun, manager of environmental services for the Western Lake Superior Sanitary District, the agency responsible for cleaning up wastewater for a 500-square-mile area around the city. Officials have persuaded the local dental community to recycle mercury waste from tooth fillings rather than throw it down drains. The city council also has taken strict measures, making Duluth the first U.S. city to ban mercury from thermometers and hospital equipment. "Such measures are a step in the right direction," says Lipman.

Death by 1,000 Sraws 
The Great Lakes may be the largest freshwater system on Earth, but water shortages nevertheless threaten the basin. The reason can be found in towns such as Waukesha, Wisconsin, where 66,000 residents require 20 million gallons of water daily even as the underground water sources that have quenched the town’s thirst are giving out. Wells are drilled deeper and deeper as water levels fall 7 to 10 feet yearly, but these deep wells are potentially toxic with radium, a naturally occurring substance linked to bone cancer. The federal Environmental Protection Agency has ordered Waukesha to find safer sources, which the city plans to do by tapping a shallow aquifer and shutting off toxic wells. That approach will work only for a decade or so, however.

The solution preferred by Waukesha is to take water from Lake Michigan, only 18 miles to the east. But that plan hits smack into a legal barrier designed to protect the Great Lakes. Waukesha sits outside the Great Lakes Basin, and in 1986 Congress gave each governor of the eight Great Lakes states veto power over any out-of-basin water diversions in order to ensure that water pumped from the Great Lakes eventually finds its way back home.

So far, the governors have been rigid about keeping water in the basin. Although supplying water to Waukesha would not affect the level of water in the Great Lakes significantly, such diversions could lead to requests for water from other thirsty communities. "No one is looking at Waukesha on its own as a threat," says Noah Hall, an NWF water resources specialist. "It’s the precedent, the opening of the door, that we’re concerned about." Supplying water to any entity outside the basin could, as one water expert put it, become death by 1,000 straws for the Great Lakes.

Meanwhile, the regulations for all new water withdrawals may change as the governors, working with Canadian officials, develop management policies within the next year. To protect the lakes in an increasingly thirsty world, the governors are committed to developing water conservation and environmental protection standards for use of this precious resource.

When Alien Species Invade 
The Great Lakes are home to at least 162 nonnative aquatic species that have invaded the basin, competing with native species and harming local habitats. The first known invader was the serpentlike sea lamprey, which uses barbed jaws to attach itself to the sides of fish and suck out blood and tissue. Arriving in the 1820s, when the Erie Canal opened a pathway from the St. Lawrence River into the lakes, lampreys rampaged through the ecosystem, helping to drive down fish populations. Today, these invaders are largely under control.

Between 1959 and 2000, 36 of the 50 invaders that established themselves in the Great Lakes came from ship ballast tanks emptied in lake waters. Among them was the zebra mussel, which is crowding out native species of mollusk. Moreover, declines in yellow perch and in the body weight of lake whitefish may have resulted from changes in the food web that coincide with the arrival of zebra mussels and other organisms.

More invaders are doubtless on the way. Even now, three Asian carp species, voracious eaters of plankton, mollusks and crustaceans, are heading up the Mississippi River toward the Great Lakes. One of the species, the bighead carp, has swarmed up the Chicago River into the canal that empties into Lake Michigan. This carp can weigh in excess of 100 pounds and leap from the water with such vigor that it has actually knocked anglers out of boats. Right now, only an electric barrier, first turned on in 2002, blocks its movement into the lake, but it lies so low that the high-vaulting fish may leap over it. Authorities are hoping to put in a taller barrier, at a cost of $6.5 million.

Meanwhile, invasive species soon may have greater access to the lakes. "The U.S. Army Corps of Engineers is seeking to expand ship navigation in the Great Lakes," says NWF’s Tim Eder, "which could spur an influx of invasive species from ship ballast water."

Superior Dangers Ahead 
Development along lakeshores and tributaries is a burgeoning problem in the Great Lakes Basin. Several examples occur along just a small portion of the southern shore of Lake Superior, presently the cleanest of the Great Lakes.

One of the biggest development threats is an underground nickel and copper mine being considered by Kennecott Minerals Company for the Yellow Dog Plains, a woodland near Big Bay, Michigan, often touted as the wildest remaining portion of the Great Lakes Basin. Because the potential mine site includes sulfide ores, which produce sulfuric acid when in contact with air, local conservationists fear the mine will send acid, heavy metals and other toxic chemicals into nearby wetlands and streams and into Lake Superior. Among the streams that could be affected is the only one on the south side of the lake that is still home to coasters, a rare type of brook trout that also lives in open lake waters. "The mine threatens not only Lake Superior but all wetlands and streams that would lie between the mine and the lake," says Michelle Halley, an attorney who provides counsel to NWF on Great Lakes issues.

Officials at Kennecott, which owns thousands of acres of mineral rights in Marquette County, say they have not yet decided whether to proceed with the mine, although they have tested 25 sites in the area since 1994 at a cost of about $50,000 per site and have spent millions of dollars acquiring land and mineral rights. They plan to complete tests this year. Meanwhile, their activities are attracting other mining companies to the area, suggesting that the Yellow Dog Plains could fall victim to a mining boom. "Kennecott is being secretive about its plans," Halley says. "The company needs to come clean with local people."

Mining isn’t the only problem on Lake Superior’s south shore. Home building within the Marquette, Michigan, area is expected to increase by 80 percent within the next 10 years, says Halley. "More and more people want to build right on rivers and lakeshores around Marquette," she says. "Developers who are not sensitive to the landscape and watersheds damage habitat and increase the silting and pollution of lakes and streams."

At Whitefish Point, east of Marquette, the Great Lakes Wreckage Historical Society is building a museum complex on lake dunes, threatening nearby wetlands used during migration by sandhill cranes, up to 10,000 loons, 25,000 red-necked grebes and 20,000 migrating raptors, says Jim Rooks, a local activist based at Copper Harbor, Michigan. The wetlands also provide critical habitat for endangered piping plovers.

Roger Di Silvestro is a senior editor for this magazine. For more information on the Great Lakes, go to NWF Programs . Or read Di Silvestro's "Great Lakes Primer."

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