The Great Lakes cover approximately 95,000 square miles (250,000 square kilometers) and hold more than 20% of the Earth’s surface fresh water. More than 30 million people in the US and Canada depend on them for drinking water. The lakes support a multi-billion dollar maritime economy, and the land around them provided many raw materials – timber, coal, iron – that fueled the Midwest’s emergence as an industrial heartland.
Despite their immense importance, the lakes were eroded for more than a century as industry and development expanded around them. By the 1960s, rivers such as the Cuyahoga, Buffalo, and Chicago were so polluted that they caught fire. In 1965, McLean’s magazine called Lake Erie, the smallest and shallowest Great Lakes, “an odorous, mud-covered graveyard” that “may already have no return.” Lake Ontario was not far behind either.
In 1972, the US and Canada signed the Great Lakes Water Quality Agreement, a landmark agreement to clean up the Great Lakes. Now, 50 years later, they have made progress, but with new challenges and a lot of unfinished business.
I have studied the environment and written four books on US-Canadian management of their shared frontier waters. In my view, the Great Lakes Water Quality Agreement was a watershed moment for environmental protection and an international model for regulating transboundary pollution. But I believe that the people of America and Canada were satisfied soon after the initial success of the agreement thwarted the Great Lakes.
starting with phosphate
A major step forward in Canada-US joint management of the Great Lakes came in 1909 when they signed the Boundary Water Treaty. The Great Lakes Water Quality Agreement builds on this foundation by creating a framework to allow the two countries to cooperatively restore and protect these border waters.
However, as an executive agreement rather than a formal government-to-government treaty, the treaty has no legal mechanism for enforcement. Instead, it is up to the US and Canada to meet their commitments. The International Joint Commission, an agency created under the Boundary Waters Treaty, executes the agreement and tracks progress towards its goals.
The agreement set common goals for controlling a variety of pollutants in Lake Erie, Lake Ontario and the upper St. Lawrence River, the most polluted sections of the Great Lakes System. A major objective was to reduce nutrient contamination, particularly phosphates from detergents and sewage. These chemicals promoted giant blooms of algae that then died and disintegrated, leaving the water lacking in oxygen.
Like the national water pollution laws enacted at the time, these efforts focused on point sources – discreet, easily identifiable points of contaminants such as discharge pipes or wells.
Initial results were encouraging. Both governments invested in new sewage treatment facilities and persuaded manufacturers to reduce the phosphate load in detergents and soaps. But as phosphorus levels in the lakes declined, scientists soon discovered other problems.
In 1973, scientists reported a surprising discovery in fish from Lake Ontario: Mirex, a highly toxic organochloride insecticide used primarily to kill ants in the southeastern US. , The contamination was so severe that New York State banned the eating of popular types of fish such as coho salmon and lake trout from Lake Ontario from 1976 to 1978, leading to commercial and sport fishing in the lake.
In response to this 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 toxins. This version formally adopted an ecosystem approach to pollution control that considered 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 scholars of North American environmental regulations acknowledge, both countries also often allowed industries to police themselves.
Since the 1990s, studies have identified lead, copper, arsenic and other toxic pollutants in as well as around the Great Lakes, including PCBs, DDT and chlordane. Some of these chemicals continued to show up because they were persistent and took a long time to break down. Others were banned but were derived from contaminated sites and sediments. Still others came from a variety of point and non-point sources, including several industrial sites centered on shorelines.
Many dangerous sites have been gradually cleared. However, toxic pollution remains a major problem in the Great Lakes, which is largely not appreciated by the public, as these substances do not always make the water foul or smell bad. Many fish advisories are still in effect throughout the region due to chemical contamination. Industry constantly brings new chemicals to market, and regulations lag far behind.
non point source
Another major challenge is non-point source pollution – discharges that come from multiple dispersed sources, such as runoff from farm fields.
Nitrogen levels in lakes have increased significantly due to agriculture. Like phosphorus, nitrogen is a nutrient that causes large blooms of algae in fresh water; It is one of the main ingredients in fertilizer, and is also found in human and animal waste. Sewage overflows from cities and waste and manure runoff from industrial agriculture carry huge amounts of nitrogen into lakes.
As a result, algae blooms have returned to Lake Erie. In 2014, toxins in one of those toys forced officials in Toledo, Ohio to shut down the public water supply for half a million people.
One way to address non-point source pollution is to set an overall limit for the release of the problem pollutant into local water bodies and then work to bring the discharge up to that level. These measures, known as total maximum daily loads, have been implemented or are in development for parts of the Great Lakes basin, including western Lake Erie.
But this strategy depends on the states, as well as on voluntary steps by farmers to make them pollution free. Some Midwesterners would prefer a regional approach, like the strategy for the Chesapeake Bay, where states asked the US government to write a comprehensive federal TMDL for major pollutants for the Gulf’s entire watershed.
In 2019, Toledo voters adopted the Lake Erie Bill of Rights, which would have allowed citizens to sue if Lake Erie was polluted. The farmers challenged the measure in court, and it was declared unconstitutional.
heat and flood
Climate change is now complicating efforts to clean up the Great Lakes. Warmer waters can affect oxygen concentrations, nutrient cycling and food webs in lakes, potentially exacerbating problems and turning infestations into major challenges.
Climate change-induced flooding threatens to contaminate public water supplies around lakes. Record-high water levels are eroding shorelines and ruining infrastructure. And new problems are emerging, including microplastic pollution and “forever chemicals” such as PFAS and PFOA.
It will be challenging for the US and Canada to make progress on this complex problem. Key steps include prioritizing and funding the cleanup of toxic areas, finding ways to stop agricultural runoff, and building new sewer and stormwater infrastructure. If both countries can muster the will to aggressively tackle pollution problems, as they did with phosphates in the 1970s, the Great Lakes Water Quality Agreement provides them with a framework for action.