Great Lakes Water Pollution: Causes And Concerns

The Great Lakes, comprising Lakes Superior, Michigan, Huron, Erie, and Ontario, are the largest source of fresh water on Earth. They span 750 miles from West to East and are situated across nine state/territory borders in Canada and the United States. The lakes are a crucial source of drinking water for over 40 million people and support ecosystems, wildlife, and local economies. However, human activities have severely impacted the Great Lakes ecosystem, and pollution has become a significant concern. The leading causes of water pollution in the Great Lakes include agricultural runoff, industrial waste, sewage, and plastic waste.

Plastic pollution

The Great Lakes, comprising Lakes Huron, Ontario, Michigan, Erie, and Superior, are the largest source of freshwater on Earth. However, they are under threat from plastic pollution, with an estimated 22 million pounds of plastic ending up in the lakes annually.

Plastic accounts for approximately 80-86% of the litter on the shorelines of the Great Lakes. The plastic waste includes microbeads from consumer products, pellets from the plastic manufacturing industry, and waste from beachgoers, shipping, and fishing activities. Single-use plastics are a major contributor to the problem, with items being used once and left behind. Microplastics, such as those from microbeads and microfibers from clothing, are also a significant concern as they can be consumed by wildlife and potentially enter the food chain.

A study by the Rochester Institute of Technology found that nearly 10,000 metric tons of plastic debris enter the Great Lakes each year from the United States and Canada. Lake Michigan receives the highest amount of plastic pollution, followed by Lake Erie and Lake Ontario. The study also revealed that major population centers are the primary sources of plastic pollution, with Chicago, Toronto, Cleveland, and Detroit releasing more plastic particles than accumulate on their shorelines.

To combat the plastic pollution crisis, various efforts have been made. The Alliance for the Great Lakes has worked with partners across the region to support legislation addressing plastic production and reduction, improving reuse systems, and enhancing data collection for informed policymaking. The fight for legislation to phase out microbeads in personal care products has also been a significant victory. Additionally, volunteer initiatives like the Adopt-a-Beach program play a crucial role in keeping plastic out of the lakes. However, it is recognized that a more systemic solution is needed, and reducing the production of single-use plastics and holding producers responsible are vital steps toward mitigating the issue.

Industrial waste

Lake Michigan, for instance, is surrounded by the world's largest concentration of pulp and paper mills to its north and a highly urbanized area to its south. The mills introduce waste into the lake, and the southern region receives pollution from the densely populated Milwaukee and Chicago areas. This includes untreated sewage, which can enter the lake during heavy rainstorms when the volume of wastewater exceeds the capacity of treatment plants.

In the past, industrial waste was recognized as one of the least serious pollutants in the Great Lakes, yet also the most easily controlled. This led to the passing of legislation and enforceable clean-up orders in state and federal courts. Despite these efforts, industrial waste continues to impact the Great Lakes. For example, Lake Erie was declared "dead" in 1970 due to oil spills in the Detroit River, which threatened the lives of thousands of ducks, geese, and other native wildlife species.

The environmental impacts of industrialization and urbanization have taken a toll on the Great Lakes ecosystem. Concentrations of historic pollutants, such as mercury, remain a concern, and new pollutants, including pharmaceuticals and plastic waste, are also present in the water. These pollutants have far-reaching consequences, affecting not only the wildlife but also the health and economic opportunities of the millions of people who rely on the lakes for their livelihood.

Sewage

One of the main issues with sewage pollution in the Great Lakes is the combined sewer systems used by many wastewater treatment facilities in the region. These systems collect stormwater runoff and domestic wastewater in the same pipes. During heavy rainfall or runoff, the treatment facilities can become overloaded, leading to untreated sewage being redirected into the lakes. This untreated sewage contains harmful contaminants that can bypass the treatment process and end up in the water.

The impact of sewage pollution on the Great Lakes is exacerbated by the fact that the lakes are essentially a closed system. With only about 1% of the water leaving the basin each year, the pollutants that enter the lakes remain and become concentrated over time. This concentration of pollutants has severe ecological and health consequences. Sewage contains harmful bacteria, viruses, and chemicals that can kill fish and other aquatic life, as well as contaminate drinking water sources.

Additionally, sewage pollution contributes to the excessive growth of algae in the Great Lakes. This algal bloom is fueled by the high levels of nutrients, such as nitrogen and phosphorus, present in sewage and other agricultural runoff. The excessive algae can lead to oxygen depletion in the water, creating "dead zones" where aquatic life cannot survive. It also has economic implications, impacting tourism, fishing, and other industries that depend on the lakes.

To address the issue of sewage pollution in the Great Lakes, several measures can be implemented. These include separating storm and sewage systems, constructing holding tanks to capture overflow during heavy rainfall, and improving the capacity and efficiency of wastewater treatment facilities. By taking these steps, the amount of untreated sewage entering the lakes can be significantly reduced, improving water quality and ecological health.

Agriculture

The Great Lakes are a set of five lakes: Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario. These lakes are used for fishing, boating, transportation of goods, and recreational activities. They are also crucial for sustaining wildlife and ecosystems. However, agricultural activities have negatively impacted the water quality of the Great Lakes.

One of the main ways agriculture contributes to water pollution in the Great Lakes is through nutrient pollution. Agricultural practices, such as the use of fertilizers, soil erosion, and animal manure, introduce excessive amounts of nitrogen and phosphorus into the water. This leads to the growth of algae, which can be harmful to aquatic life and disrupt the natural balance of the ecosystem. Nutrient pollution can also come from stormwater runoff, which carries pollutants from hard surfaces into local waterways.

Additionally, the industrialization and urbanization surrounding the Great Lakes have been influenced by agricultural activities. For example, the northern region of Lake Michigan, which is surrounded by the world's largest concentration of pulp and paper mills, receives significant waste from these mills. The southern region of Lake Michigan, facing the highly urbanized area in the Great Lakes region, receives pollution from the millions of people in the Milwaukee and Chicago areas.

Agricultural practices also contribute to the overall pollution load in the Great Lakes, which, as a closed system, have a unique vulnerability to pollutants. Only about one percent of the water in the lakes leaves the basin each year, meaning that pollutants dumped into the lakes remain and become concentrated over time. This includes historical pollutants, such as mercury, and new pollutants, such as pharmaceuticals and plastic waste.

Urbanisation

Urbanization has had a significant impact on water pollution in the Great Lakes. The Great Lakes—Lake Huron, Ontario, Michigan, Erie, and Superior—are a crucial source of drinking water for nearly 40 million people in Canada and the United States. They also support ecosystems, provide recreational activities, and facilitate transportation and economic opportunities. However, the environmental impacts of urbanization, along with other factors, have taken a toll on the delicate Great Lakes ecosystem.

One of the primary ways urbanization contributes to water pollution in the Great Lakes is through the use of potentially polluting chemicals in urban areas. These chemicals, such as road salts, fertilizers, and pesticides, are often applied directly to urban surfaces and can make their way into the lakes. Additionally, substances like gasoline are stored in the subsurface, and septic systems can release pollutants into the water. The complex infrastructure of drains, pipes, and tunnels in urban areas can create an "urban karst," an artificial aquifer that influences groundwater flow and contaminant transport.

The proximity of large cities to the Great Lakes further exacerbates the problem. As cities rely heavily on lake water as a convenient and inexpensive source of supply, urban groundwater issues are often overlooked until serious problems arise. Rising water tables, for example, can lead to the re-emergence of springs contaminated by urban pollutants. Additionally, urban development can reduce aquifer recharge by creating an impermeable seal with asphalt, concrete, and roof-topped structures. This limits natural aquifer replenishment and contributes to water pollution.

Furthermore, the concentration of people in urban areas surrounding the Great Lakes increases pollution levels. For example, Lake Michigan, the second-largest in volume, is surrounded by the most urbanized area in the Great Lakes region, including cities like Milwaukee and Chicago. Lake Ontario is also influenced by urbanization, with cities like Hamilton and Toronto located on its shores. Lake Erie, the smallest and shallowest lake, has suffered the most from urbanization, with high levels of pollution from the surrounding urban and industrial areas.

The impact of urbanization on water pollution in the Great Lakes is evident, and efforts to mitigate these effects are ongoing. Governmental actions, commissions, and international agreements have been put in place to address the issue. However, as the population continues to grow and urban areas expand, it is crucial to prioritize sustainable practices, proper waste management, and the reduction of pollutant use in urban environments to protect the delicate ecosystem of the Great Lakes.

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