CEA in the News

Great Lakes Series: Lake Erie, breathless

Marine Ernoult, Francopresse / February 21, 2023

FRANCOPRESSE – Despite efforts to reduce pollution since the 1960s, polluting discharges continue to wreak havoc on Lake Erie. The stretch of fresh water suffers from eutrophication, which favors the development of blue algae. To stop their proliferation, scientists and ecologists are calling for changing agricultural practices and restoring wetlands.

It has the smallest volume of water, is the shallowest, but is the most polluted of the Great Lakes.

Lake Erie is "sick", notes, bitterly, Jérôme Marty, director general of the International Association of Great Lakes Research , also a member of the Great Lakes Scientific Advisory Committee of the International Joint Commission (a Canadian-American body that oversees the management and protection of boundary waters).

The State of the Great Lakes Report 2022 confirms that the lake is in “poor” condition.

In the west of the lake, all the indicators are red. Almost every summer, blooms (brutal outbreaks) of cyanobacteria are observed in this area. Also known as blue algae, these microorganisms cause the water to change color and secrete toxins that are harmful to animals and humans. They can cause neurological, digestive, dermatological and even fatal damage.

The consequences on human health are all the more worrying as many cities depend on the lake for their drinking water supply. This is the case of Toledo , in the American state of Ohio, where the 400,000 inhabitants were deprived of tap water in August 2014 because of the presence of a toxic compound synthesized by cyanobacteria in the Lake Erie.

Lack of oxygen

Blue-green algae also have an impact on the environment.

"When they colonize an environment, they end up killing all forms of aquatic life," warns Mike McKay, director of the Great Lakes Institute for Environmental Research at the University of Windsor, Ontario. In Lake Erie, there are anoxic zones , where the water is almost devoid of oxygen due to excess algae.

Jérôme Marty explains that cyanobacteria also disrupt the food chain: "They have a low nutritional quality, so zooplankton will develop less and will not feed fish properly." The gray trout thus almost died out in the lake for this reason.

This pollution is old. From the 1960s, the lake came close to asphyxiation. In a warm and shallow environment, the discharge from treatment plants causes eutrophication. In other words, under the massive supply of nutrients, long filamentous algae proliferate.

“Sewage treatment in the surrounding municipalities was insufficient, which led to an increase in phosphorus concentrations in the lake,” explains Mike McKay. To stem the threat, Canada and the United States adopted the first Great Lakes Water Quality Agreement in 1972.

Even today, environmental protection associations welcome this treaty. “We have made a radical change. Pollution has become a concern of the public authorities”, rejoices Peter Huston, member of the board of directors of the American organization Lake Erie Foundation.

Agricultural pressure

“It pushed the authorities to identify the problematic treatment plants and to modernize them. We have greatly reduced the quantities of nutrients released,” explains Derek Coronado, research and policy coordinator at the Citizens Environment Alliance , located in Windsor, Ontario.

The early 2000s, however, marked a step back. Under the effect of urban development and intensive agriculture in the Lake Erie watershed , cyanobacteria have returned in force.

From now on, it is no longer the treatment plants that are in question, but the agricultural discharges loaded with nitrogen and phosphorus. On the American side, Peter Huston points to the large crops and industrial farms around the Maumee and Sandusky rivers in Ohio which flow into the Erie.

"With the era of genetically modified, herbicide-resistant plants, farmers began to apply large amounts of fertilizer," says Mike McKay. Some of it does not stay in the ground and flows into the lake.

The rise in water temperatures and the multiplication of extreme meteorological events, due to global warming, further accentuate the phenomenon. “ Blooms appear in places where we had never seen them before,” worries Jérôme Marty.

Lack of political will

To take into account the close interactions between all these threats, the Great Lakes Water Quality Agreement was modernized in 2012. The stated objective is to reduce phosphorus discharges into the lake by 40%. 'here in 2030. “We are not on the right track”, regrets Peter Huston.

Derek Coronado believes that the agreement should have focused on preventing pollution at source, with a "zero discharge" ambition and the application of a polluter-pays principle, "to charge the real price environmental damage to those responsible".

The specialist also denounces the non-legally binding nature of this agreement: “We need a treaty that obliges Canada and the United States to modify their national regulations accordingly.”

In the meantime, how to clean up the water? Cleaning the lake to remove the sediment would be a “Herculean project” expensive and difficult to set up, according to Jérôme Marty.

Changing agricultural practices and radically reducing the use of chemical inputs are the two preferred levers. “We know the solutions, but we do not put them into practice. The problem is the lack of political will,” insists Derek Coronado.

"It's complicated, because the lake is shared between two countries, several levels of competence with different regulations, which sometimes have trouble agreeing," adds Jérôme Marty.

convince farmers

Precision agriculture, crop rotation, increased diversity of cultivated varieties, mechanical weeding, the tools allowing a reduction of pesticides are however numerous.

“We have to convince farmers that this is a winning strategy, that they can reduce the use of chemical inputs without altering their yields and their income,” underlines Mike Mckay.

Don Ciparis, the last president to date of the National Farmers Union ( UNF ) of Ontario recognizes that agriculture in the province remains a major consumer of synthetic inputs: “It is not decreasing. Many farmers want to produce more by using more fertilizer. It's hard to change ways of doing things that have been going on for generations."

The manager nevertheless assures that soil health is becoming "more and more a topic of conversation" within the profession.

Jérôme Marty calls, for his part, to focus on the restoration of riparian ecosystems. He speaks in particular of restoring the banks and the degraded, even destroyed wetlands: “They play a role of sponge, their vegetation filters the nutrients upstream.”

The matter is urgent, because wetlands are in sharp decline. "Many of them have been drained for economic development projects," laments the expert.

Even if we put an end to all toxic effluents, “the blooms will not disappear”, he warns. The many nutrients trapped at the bottom of the lake for decades will continue to rise to the surface and feed the blue-green algae.

new threats

New toxic chemical compounds are regularly detected in Lake Erie. Fluoroalkyl substances (known as PFAS , used in industry for their non-stick and waterproof properties), flame retardants, pharmaceutical residues, sweeteners … the list goes on.

Worse, the quantities found are high due to the shallow depth of the lake.

The concentrations of microplastics are also "increasingly strong", warns Peter Huston.

“Because of heavy industry, we have inherited many contaminants that persist for an extremely long time in the environment. They are still in suspension or buried in the sediment at the bottom,” explains Mike McKay.

“We underestimate the impacts of these contaminants and especially the multiplied toxic effect of their mixture”, continues Jérôme Marty.

This chemical pollution contaminates the entire food chain, with consequences for human health. PFAS, for example, are suspected of having multiple deleterious effects : cancers, disturbances of the endocrine system, increased cholesterol levels, reduced fertility or delayed fetal development.

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