RESEARCH STARTER

Pollution of Lake Erie

Lake Erie, the shallowest and southernmost of the Great Lakes, has faced significant pollution challenges over the years, primarily due to human activities. Historically, even before European settlement, the lake's ecosystem was at risk, but it saw severe degradation with the introduction of chemical fertilizers and industrial waste during the mid-twentieth century. This pollution led to a phenomenon known as eutrophication, where excessive nutrients caused rapid algae growth, negatively impacting water quality and aquatic life. The oxygen depletion resulting from decaying algae suffocated bottom-dwelling organisms and disrupted food chains, leading to declines in fish populations.

Intensive agricultural practices and industrial discharges introduced heavy metals and toxic compounds into the lake, prompting fish consumption advisories due to contamination risks. In response to public concern over the lake's poor condition, collaborative efforts between the United States and Canada began in the 1960s, including the establishment of the Great Lakes Water Quality Agreement to mitigate pollution. Although there have been improvements in water treatment and fish populations, challenges remain, with toxic algae blooms reported as a continuing threat to both human health and the ecosystem. The lake supports around 11 million residents who rely on it for drinking water, highlighting the critical need for ongoing environmental management and restoration efforts.

Full Article

  • IDENTIFICATION: Large freshwater lake bordering Ontario, Canada, and the US states of Michigan, Ohio, Pennsylvania, and New York

In ecological trouble even before European settlement of its region, Lake Erie was badly damaged by human tampering with its ecosystem and the careless introduction of chemical fertilizers and industrial wastes. By the mid-twentieth century, the lake was severely polluted, but sustained efforts to rehabilitate it that began in 1965 gradually brought about a general recovery.

Lake Erie, the shallowest and southernmost of the Great Lakes, was far along in the process of eutrophication, or natural aging, prior to settlement by Europeans. Early settlers accelerated this process by draining coastal wetlands and stripping away vegetation, which increased the amount of sediment carried to the lake. With the advent of widespread agriculture, artificial fertilizers also began to wash into Lake Erie, which contributed to the overenrichment of the lake’s waters. Sewage and fertilizers, such as phosphorus and nitrogen, caused the rapid growth of surface algae scums, which affected the taste and odor of drinking water supplies, clogged water intakes, and forced beach closures. More importantly, decaying algae consumed the water’s oxygen, leading to the suffocation of bottom-dwelling organisms. Eventually, desirable fish stocking the lake were stressed by a lack of adequate food, and populations declined.

Industries along the lake’s main tributaries contributed to the problem by injecting industrial wastes, oil, floating solids, and heavy metals into the water supply. Heavy metals such as lead and mercury, as well as organic chemicals such as polychlorinated biphenyls (PCBs) and dioxin, magnify in concentrations as they pass up the food chain. These bioaccumulation and biomagnification effects may increase levels of toxic materials by one million times in fish such as salmon and trout. Fish consumption advisories were required for some species because of contamination levels. By 1965, Lake Erie had become so polluted that public indignation over its condition led to action by government officials.

Four US states (Michigan, New York, Pennsylvania, and Ohio) and one Canadian province (Ontario) share responsibility for managing Lake Erie. The International Joint Commission was established by Canada and the United States in 1909 to arbitrate disputes over shared boundary waters. In 1972, the commission established the Great Lakes Water Quality Agreement, which provided for a reduction in nitrogen and phosphorus discharge in Lake Erie by improving the municipal sewage treatment systems. The retention of sanitary and storm-sewer overflow for later treatment greatly reduced health problems in the region, and beach closures at Lake Erie became less frequent with improved treatment of sewage.

The International Reference Group on Great Lakes Pollution from Land Use, under the International Joint Commission Authority, prepared reports that provided the groundwork for the ecosystem approach to reducing pollution in Lake Erie, promulgated in the 1978 revisions to the Water Quality Agreement. The agreement states that the programs must center on the physical, chemical, and biological relationships among air, land, and water resources. The ecosystem approach mandated by the 1978 agreement means that standards and monitoring methods must take into account the air, land, and water movement of pollutants and their risks to humans and other organisms.

The Great Lakes Fishery Commission, created in 1955 by Canada and the United States, is concerned with restoring and stocking lake fish. The population of whitefish in the lake has shown signs of recovery. Lake trout and coho salmon are stocked in the lake, and walleye and yellow perch are managed for recreational and commercial fishing. Tests have also revealed that the levels of PCBs in some Lake Erie fish have diminished over time.

In 1985, the Great Lakes Charter was inaugurated to resist the transfer of Great Lakes water to other areas. The charter authorized the development of an information database for surface water and groundwater resources. In 1986, the Great Lakes Toxic Substances Control Agreement (GLTSCA) was formed to coordinate the actions of the Great Lakes states to reduce toxic substances in the basin. The 1987 protocol to the Great Lakes Water Quality Agreement called for forming specific ecosystem objectives and indicators. This approach has enhanced the evolution of full ecosystem management strategies, which incorporate mathematical modeling.

The US Environmental Protection Agency (EPA) reported in 2025 that approximately 12 million people lived in the Lake Erie watershed. Of these inhabitants, about 11 million people depend on the lake for drinking water. In 2014, a toxic algae bloom caused a water service interruption for almost half a million people in northwestern Ohio and southeastern Michigan. Despite a history of such blooms, Ohio omitted Lake Erie from a list of impaired waterways. In January 2018, the EPA requested more data from Ohio regarding the lake’s pollution levels. In 2024, excessive algal growth remained the largest threat to the health of Lake Erie’s ecosystems and the people who reside near its shores. Drinking water remained a threatened resource as the summers of 2020 through 2025 saw record algae blooms. Warmer waters resulting from climate change and high phosphorus loads also led to longer-lasting blooms; in 2025, researchers detected the toxin microcystin in Lake Erie in April, the earliest detection on record. These issues affect the health of the lake’s ecosystem, humans and animals, and industries such as tourism.


Bibliography

Burkholder, Matt. "How We're Securing Clean Water for Ohio." The Nature Conservancy, 11 Aug. 2022, www.nature.org/en-us/about-us/where-we-work/united-states/ohio/stories-in-ohio/securing-clean-water. Accessed 22 Sept. 2025.

Caldwell, Lynton Keith, editor. Perspectives on Ecosystem Management for the Great Lakes: A Reader. State U of New York P, 1988.

Ellison, Garret. "Lake Erie Harmful Algae Blooms Are 'Getting Worse,' Say Forecasters." Michigan Live, 30 June 2024, www.mlive.com/public-interest/2024/06/lake-erie-harmful-algae-blooms-are-getting-worse-say-forecasters.html. Accessed 22 Sept. 2025.

Grady, Wayne. The Great Lakes: The Natural History of a Changing Region. Greystone Books, 2007.

"Lake Erie: From Green to Clean ." The National Wildlife Federation Blog, 12 June 2024, blog.nwf.org/2024/06/lake-erie-from-green-to-clean. Accessed 22 Sept. 2025.

“Lake Erie.” US Environmental Protection Agency, 12 May 2025, www.epa.gov/greatlakes/lake-erie. Accessed 22 Sept. 2025.

McGucken, William. Lake Erie Rehabilitated: Controlling Cultural Eutrophication, 1960’s-1990’s. U of Akron P, 2000.

Spangler, Todd. “EPA Wants More Data on Lake Erie Pollution.” Detroit Free Press, 18 Jan. 2018, www.freep.com/story/news/local/michigan/2018/01/18/epa-lake-erie-pollution/1043683001. Accessed 22 Sept. 2025.

Full Article

  • IDENTIFICATION: Large freshwater lake bordering Ontario, Canada, and the US states of Michigan, Ohio, Pennsylvania, and New York

In ecological trouble even before European settlement of its region, Lake Erie was badly damaged by human tampering with its ecosystem and the careless introduction of chemical fertilizers and industrial wastes. By the mid-twentieth century, the lake was severely polluted, but sustained efforts to rehabilitate it that began in 1965 gradually brought about a general recovery.

Lake Erie, the shallowest and southernmost of the Great Lakes, was far along in the process of eutrophication, or natural aging, prior to settlement by Europeans. Early settlers accelerated this process by draining coastal wetlands and stripping away vegetation, which increased the amount of sediment carried to the lake. With the advent of widespread agriculture, artificial fertilizers also began to wash into Lake Erie, which contributed to the overenrichment of the lake’s waters. Sewage and fertilizers, such as phosphorus and nitrogen, caused the rapid growth of surface algae scums, which affected the taste and odor of drinking water supplies, clogged water intakes, and forced beach closures. More importantly, decaying algae consumed the water’s oxygen, leading to the suffocation of bottom-dwelling organisms. Eventually, desirable fish stocking the lake were stressed by a lack of adequate food, and populations declined.

Industries along the lake’s main tributaries contributed to the problem by injecting industrial wastes, oil, floating solids, and heavy metals into the water supply. Heavy metals such as lead and mercury, as well as organic chemicals such as polychlorinated biphenyls (PCBs) and dioxin, magnify in concentrations as they pass up the food chain. These bioaccumulation and biomagnification effects may increase levels of toxic materials by one million times in fish such as salmon and trout. Fish consumption advisories were required for some species because of contamination levels. By 1965, Lake Erie had become so polluted that public indignation over its condition led to action by government officials.

Four US states (Michigan, New York, Pennsylvania, and Ohio) and one Canadian province (Ontario) share responsibility for managing Lake Erie. The International Joint Commission was established by Canada and the United States in 1909 to arbitrate disputes over shared boundary waters. In 1972, the commission established the Great Lakes Water Quality Agreement, which provided for a reduction in nitrogen and phosphorus discharge in Lake Erie by improving the municipal sewage treatment systems. The retention of sanitary and storm-sewer overflow for later treatment greatly reduced health problems in the region, and beach closures at Lake Erie became less frequent with improved treatment of sewage.

The International Reference Group on Great Lakes Pollution from Land Use, under the International Joint Commission Authority, prepared reports that provided the groundwork for the ecosystem approach to reducing pollution in Lake Erie, promulgated in the 1978 revisions to the Water Quality Agreement. The agreement states that the programs must center on the physical, chemical, and biological relationships among air, land, and water resources. The ecosystem approach mandated by the 1978 agreement means that standards and monitoring methods must take into account the air, land, and water movement of pollutants and their risks to humans and other organisms.

The Great Lakes Fishery Commission, created in 1955 by Canada and the United States, is concerned with restoring and stocking lake fish. The population of whitefish in the lake has shown signs of recovery. Lake trout and coho salmon are stocked in the lake, and walleye and yellow perch are managed for recreational and commercial fishing. Tests have also revealed that the levels of PCBs in some Lake Erie fish have diminished over time.

In 1985, the Great Lakes Charter was inaugurated to resist the transfer of Great Lakes water to other areas. The charter authorized the development of an information database for surface water and groundwater resources. In 1986, the Great Lakes Toxic Substances Control Agreement (GLTSCA) was formed to coordinate the actions of the Great Lakes states to reduce toxic substances in the basin. The 1987 protocol to the Great Lakes Water Quality Agreement called for forming specific ecosystem objectives and indicators. This approach has enhanced the evolution of full ecosystem management strategies, which incorporate mathematical modeling.

The US Environmental Protection Agency (EPA) reported in 2025 that approximately 12 million people lived in the Lake Erie watershed. Of these inhabitants, about 11 million people depend on the lake for drinking water. In 2014, a toxic algae bloom caused a water service interruption for almost half a million people in northwestern Ohio and southeastern Michigan. Despite a history of such blooms, Ohio omitted Lake Erie from a list of impaired waterways. In January 2018, the EPA requested more data from Ohio regarding the lake’s pollution levels. In 2024, excessive algal growth remained the largest threat to the health of Lake Erie’s ecosystems and the people who reside near its shores. Drinking water remained a threatened resource as the summers of 2020 through 2025 saw record algae blooms. Warmer waters resulting from climate change and high phosphorus loads also led to longer-lasting blooms; in 2025, researchers detected the toxin microcystin in Lake Erie in April, the earliest detection on record. These issues affect the health of the lake’s ecosystem, humans and animals, and industries such as tourism.


Bibliography

Burkholder, Matt. "How We're Securing Clean Water for Ohio." The Nature Conservancy, 11 Aug. 2022, www.nature.org/en-us/about-us/where-we-work/united-states/ohio/stories-in-ohio/securing-clean-water. Accessed 22 Sept. 2025.

Caldwell, Lynton Keith, editor. Perspectives on Ecosystem Management for the Great Lakes: A Reader. State U of New York P, 1988.

Ellison, Garret. "Lake Erie Harmful Algae Blooms Are 'Getting Worse,' Say Forecasters." Michigan Live, 30 June 2024, www.mlive.com/public-interest/2024/06/lake-erie-harmful-algae-blooms-are-getting-worse-say-forecasters.html. Accessed 22 Sept. 2025.

Grady, Wayne. The Great Lakes: The Natural History of a Changing Region. Greystone Books, 2007.

"Lake Erie: From Green to Clean ." The National Wildlife Federation Blog, 12 June 2024, blog.nwf.org/2024/06/lake-erie-from-green-to-clean. Accessed 22 Sept. 2025.

“Lake Erie.” US Environmental Protection Agency, 12 May 2025, www.epa.gov/greatlakes/lake-erie. Accessed 22 Sept. 2025.

McGucken, William. Lake Erie Rehabilitated: Controlling Cultural Eutrophication, 1960’s-1990’s. U of Akron P, 2000.

Spangler, Todd. “EPA Wants More Data on Lake Erie Pollution.” Detroit Free Press, 18 Jan. 2018, www.freep.com/story/news/local/michigan/2018/01/18/epa-lake-erie-pollution/1043683001. Accessed 22 Sept. 2025.

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