The Great Lakes are an invaluable resource to both humans and wildlife alike – they support over 3,500 species of plants and animals, and provide drinking water to more than 40 million people in the U.S. and Canada¹. Spanning over 94,000 square miles of surface area², these lakes connect several states and regions. Across the U.S. and Canada, the Great Lakes Basin houses more than 34 million people.

An Economic Powerhouse

Not only are these lakes essential for the survival of millions of humans and animals, but they’re also extremely rewarding for the regional economy – the Great Lakes are essentially a $6 trillion business, and recreation alone generates over $52 billion in revenue annually¹. From wildlife to recreation to the economy, the Great Lakes are truly a backbone of the surrounding area.

Wisconsin has shoreline on two of the five Great Lakes: Lake Superior, and Lake Michigan – which includes Green Bay! The city of Green Bay is one of three major ports on Lake Michigan (in addition to a port in Milwaukee and Chicago)³, and the lake’s basin has the second highest population of all the Great Lakes². 

Based in the Basin

Unfortunately, the human and industrial activity surrounding the Great Lakes leads to a lot of plastic pollution entering the waterways – 22 million pounds of it per year, actually – and half of it ends up in Lake Michigan alone⁴.

Most plastic pollution in the Great Lakes originates from tributaries – smaller rivers or streams that flow into the lakes⁵. So even if you don’t live particularly close to a Great Lake or if you live in one of the Great Lakes basins, your litter could still end up there.

A “basin” is the surrounding land area that drains into a certain body of water. Below, you can observe a map of Lake Michigan’s basin – not only does it include cities along the shore like Green Bay, Sheboygan, and Milwaukee, but also cities on the Fox River – like Appleton and Oshkosh – and cities that are even further inland, almost reaching Stevens Point, Wisconsin Dells, and Antigo.

In these areas, litter on land will eventually make its way to creeks and streams – which feed into larger rivers and lakes, and eventually make their way to Lake Michigan. Once pollution (including plastic debris) reaches the lake, strong currents distribute it far and wide.

Let’s Break it Down

When plastic ends up in the Great Lakes, it breaks down over time – but doesn’t disappear. Larger plastic products like water bottles or plastic bags break apart into smaller plastic pieces, called microplastics. “Microplastics” are small bits of plastic that are less than 5mm⁶ – smaller than the eraser on the top of a pencil!

Oftentimes, these microplastics are so tiny that they often make their way into animals’ digestive systems, our drinking water, and even beer⁶! Once ingested, microplastics will continue to accumulate in an organism’s digestive system, and can lead to a plethora of health issues.

To learn more about the effect of microplastics on humans and wildlife, check out our recent blog post about the Washed Ashore Animal Advocates Stanley the Sturgeon, Giacometti the River Otter, and Rosa the Bald Eagle.

The Pellet Problem

Before it’s formed into consumable products, “raw” plastic is formed into small pellets, called nurdles, which are full of chemicals that affect the plastic’s flexibility, durability, and color⁷.

There are dozens of plastic manufacturing sites in Wisconsin along the Bay and Lake Michigan’s west shoreline⁸. When plastic pellets are being transported to and from these locations, oftentimes they accidentally spill and get washed into Lake Michigan.

Since pre-production plastic nurdles contain so many chemicals, once they reach the lake, these toxins leach into the water – harming both humans and wildlife⁷. Unfortunately, not much is known about the specific effects of these leachates in the Great Lakes region, but research is currently underway, led by the Ohio Sea Grant.

What’s the Point?

In addition to plastic pollution having negative health impacts on humans and wildlife, it also harms the Great Lakes’ economy – remember the $52 billion Great Lakes recreation industry? Well, most of that recreation is based on keeping our lakes clean.

Pollution in the Great Lakes leads to fish ingesting microplastics and deterring fisherman from fishing; the shoreline being covered in litter, which discourages kayakers and beachgoers; and the water being full of chemicals and toxins, preventing swimmers, skiers, and other people from fully enjoying the water.

In order to enjoy the Great Lakes, we have to keep them plastic-free.

Stop Plastic Pollution at the Source

Once plastic pollution reaches the Great Lakes, it’s hard to clean up – nurdles have already leeched harmful chemicals, and microplastics can be nearly impossible to remove from beaches and the water. That’s why it’s important to prevent plastic pollution from its source by consuming less plastic.

Here are a few specific ways you can lessen your own plastic consumption:

• Buy natural clothing: Fabrics like polyester and nylon are made from very thin plastic fibers, and when these materials degrade over time their fibers contribute to microplastic pollution. Whenever possible, invest in clothing that is made of natural materials like cotton, linen, or wool.
• Paper, not plastic: When grocery shopping, opt for paper bags (which degrade over time) instead of plastic ones. Or, bring your own reusable bags!
• Say “no” to single-use plastics: Much of the plastic pollution collected on Great Lakes beaches is single-use, meaning it gets used once before thrown out⁶. Instead of drinking from plastic water bottles, get a reusable one made of steel or another metal. Instead of using individually-wrapped bags of chips or snacks, opt for a larger bag that you can portion yourself – or, buy reusable metal straws instead of using plastic ones.

If you have other ways you’re lessening your plastic consumption, let us know! Reach out to marketing@www.gbbg.org to share your ideas.

Sources

1. “About the Lakes.” Great Lakes Commission, January 25, 2022. https://www.glc.org/lakes/.
2. “Great Lakes Fast Facts.” Michigan Sea Grant. Accessed July 15, 2025. https://www.michiganseagrant.org/topics/great-lakes-fast-facts/.
3. “Great Lakes Fast Facts.” Michigan Sea Grant. Accessed July 15, 2025. https://www.michiganseagrant.org/topics/great-lakes-fast-facts/.
4. Ahmed, Zahra. “10 Major Ports on the Great Lakes.” Marine Insight, April 24, 2024. https://www.marineinsight.com/know-more/ports-on-the-great-lakes/.
5. “Researchers Study Plastic Pollution in Great Lakes.” RIT. Accessed July 15, 2025. https://www.rit.edu/news/researchers-study-plastic-pollution-great-lakes.
6. “Microplastics on Great Lakes Beaches (U.S. National Park Service).” National Parks Service. Accessed July 15, 2025. https://www.nps.gov/articles/000/microplastics-on-great-lakes-beaches.htm.
7. Reda, Olivia. “20 Years of Great Lakes Litter Data.” Alliance for the Great Lakes, April 2024. https://greatlakes.org/wp-content/uploads/2024/04/AGL_AAB_VisReport_April2024_Final1.pdf.
8. Meyer, Alex. “Are Plastic ‘leachates’ Affecting Lake Erie Ecosystems?” Ohio Sea Grant College Program, September 29, 2024. https://ohioseagrant.osu.edu/news/2024/wkqys/are-plastic-leachates-affecting-lake-erie-ecosystems.