Freshwater Quality: Much unfinished work after 50 years of efforts to restore the Great Lakes


The lakes support a multibillion-dollar maritime economy, and the land around them provided many of the commodities — lumber, coal, iron — that fueled the Midwest’s rise into an industrial heartland.

Despite their immense importance, the lakes have been degraded for well over a century as industry and development spread around them. In the 1960s, rivers like the Cuyahoga, Buffalo, and Chicago were so polluted they caught fire. In 1965, Maclean’s magazine called Lake Erie, the smallest and shallowest Great Lake, “a fetid, slime-covered graveyard” that “may already have passed the point of no return.” Lake Ontario was not far behind.

In 1972, the US and Canada signed the Great Lakes Water Quality Agreement, a landmark pact to clean up the Great Lakes. Now, 50 years later, they have made progress, but there are new challenges and many unfinished business.

I study the environment and have written four books on the US-Canadian stewardship of their shared border waters. In my view, the Great Lakes Water Quality Agreement was a game changer for environmental protection and an international model for regulating transboundary pollution. But I believe that the people of the US and Canada have abandoned the Great Lakes because they became complacent too soon after the pact’s early success.

Starting with phosphates

A major step in the joint stewardship of the Great Lakes between Canada and the US came in 1909 when they signed the Boundary Waters Treaty. The Great Lakes Water Quality Agreement built on this foundation by creating a framework that allowed the two countries to work together to restore and protect these boundary waters.

However, as this is an agreement between governments and not a formal treaty between governments, the pact has no legal enforcement mechanisms. Instead, it relies on the US and Canada to honor their commitments. The International Joint Commission, an agency created under the Boundary Waters Treaty, implements the agreement and monitors progress toward its goals.

The agreement established common targets for control of a variety of pollutants in Lake Erie, Lake Ontario and the Upper St. Lawrence River, which represent the most polluted stretch of the Great Lakes system. An important goal was the reduction of nutrient pollution, especially phosphates from detergents and waste water. These chemicals fueled giant blooms of algae, which then died and decomposed, depleting the oxygen in the water.

Like the national water pollution laws enacted at the time, these efforts focused on point sources — pollutants released from discrete, easily identifiable points such as drains or wells.

Initial results were encouraging. Both governments invested in new sewage treatment plants and persuaded manufacturers to reduce phosphate levels in detergents and soaps. But as phosphorus levels in the lakes dropped, scientists soon discovered other problems.

Toxic pollutants

In 1973 scientists reported a puzzling find in fish from Lake Ontario: Mirex, a highly toxic organochloride pesticide used primarily to kill ants in the southeastern United States. The contamination was so severe that from 1976 to 1978 New York State banned the consumption of popular fish species such as coho salmon and lake trout from Lake Ontario and halted commercial and sport fishing in the lake.

In response to these and other findings, the US and Canada updated the Great Lakes Water Quality Agreement in 1978 to cover all five lakes and focus on chemicals and toxic substances. This version officially adopted an ecosystem approach to tackling pollution that takes into account the interactions between water, air and land – perhaps the first international agreement to do so.

In 1987, the two countries identified the most toxic hot spots around the lakes and adopted action plans to clean them up. However, as scientists of North American environmental regulations recognize, both nations have too often allowed the industry to self-police.

Since the 1990s, studies have identified toxic pollutants such as PCB, DDT, and chlordane in and around the Great Lakes, as well as lead, copper, arsenic, and others. Some of these chemicals continued to appear because they were stubborn and took a long time to break down. Others have been banned but leached from contaminated sites and sediments. Still others came from a range of point and non-point sources, including many coastal-centric industrial sites.

Many danger spots were slowly being rehabilitated. Toxic pollution in the Great Lakes, however, remains a colossal problem that goes largely unnoticed by the public because these substances don’t always make the water look or smell foul. Due to chemical contamination, numerous fish warnings are still in effect throughout the region. Industry is constantly bringing new chemicals to market and regulations are lagging far behind.

nonpoint sources

Another major challenge is pollution from non-point sources – discharges that come from many diffuse sources such as B. Runoff from agricultural fields. The nitrogen content in the lakes has risen sharply as a result of agriculture. Nitrogen, like phosphorus, is a nutrient that causes large algal blooms in freshwater; It is one of the main components of fertilizers and is also found in human and animal waste.

Sewage overflows from cities and waste and manure runoff from industrial agriculture contribute large amounts of nitrogen to the lakes. As a result, algal blooms have returned to Lake Erie. In 2014, toxins in one of these flowers forced officials in Toledo, Ohio, to shut off public water supplies to half a million people.

One way to address pollution from non-point sources is to set an overall limit for releases of the problem pollutant into local waters, and then work to reduce discharges to that level. These measures, known as Total Maximum Daily Loads, have been applied or are under development for portions of the Great Lakes Basin, including western Lake Erie.

But this strategy relies on governments and voluntary steps by farmers to curb the release of pollutants. Some Midwesterners would prefer a regional approach such as the Chesapeake Bay strategy, in which states required the US government to write a comprehensive federal TMDL for the major pollutants for the entire bay’s watershed.

In 2019, Toledo voters passed a Lake Erie Bill of Rights that would have allowed citizens to sue if Lake Erie became polluted. Farmers challenged the measure in court and it was declared unconstitutional.

warming and flooding

Climate change is now complicating efforts to clean up the Great Lakes. Warmer water can affect oxygen concentrations, nutrient cycling and food webs in lakes, potentially exacerbating problems and turning nuisances into major challenges.

Flooding caused by climate change threatens to contaminate the public water supply around the lakes. Record high water levels are eroding coastlines and destroying infrastructure. And new problems are emerging, including microplastic pollution and “forever chemicals” like PFAS and PFOA.

It will be a challenge for the US and Canada to make progress on this complex set of issues. Key steps include prioritizing and funding to clean up toxic zones, finding ways to stem agricultural runoff, and building new sewage and stormwater infrastructure. If the two countries can muster the will to aggressively address pollution problems, as they did with phosphates in the 1970s, the Great Lakes Water Quality Agreement gives them a framework for action.


Comments are closed.