Aerial view of the confluence of the Mississippi and Wisconsin rivers
The confluence of the Mississippi and Wisconsin rivers is photographed from an airplane on May 25, 2023, near Wyalusing State Park, Wis. Aerial support provided by LightHawk. (Drake White-Bergey / Wisconsin Watch)
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This story is a product of the Mississippi River Basin Ag & Water Desk, an editorially independent reporting network based at the University of Missouri School of Journalism in partnership with Report For America and funded by the Walton Family Foundation. Wisconsin Watch is a member of the network. Sign up for our newsletter to get our news straight to your inbox.

The Mississippi River drains more than 40% of the continental U.S. Just how much trash does it take along with it?

That’s what a group of researchers and environmental advocates wanted to find out when they began a litter analysis of a handful of cities along the river a few years ago. This fall they released what they’re calling the “first-ever snapshot of the state of plastic pollution along the Mississippi River.”

Between 2021 and 2022, volunteers from St. Paul, Minnesota; the Quad Cities area in Iowa and Illinois; St. Louis, Missouri; Greenville and Rosedale, Mississippi; and Baton Rouge, Louisiana, logged trash they found into the University of Georgia’s Debris Tracker app. The study came on the heels of a 2018 commitment from mayors along the river to reduce plastic and trash.

Although many people might think oceanside cities bear the responsibility to keep plastic and trash out of the water, the Mississippi River can act as a funnel for that trash from the heart of the country to the Gulf of Mexico. 

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The study was also meant to raise people’s awareness of the river’s role in keeping other waters clean, said Jennifer Wendt, plastic waste reduction campaign manager for the Mississippi River Cities and Towns Initiative, the mayors’ group that worked on the study.

For example, a piece of litter that someone tosses on the ground in Missouri could theoretically make its way through storm drains, to tributaries, to the Mississippi, to the Gulf of Mexico and then to the ocean.

“It may not look like a plastic beverage bottle by the time it gets to the ocean, but it’s still there,” Wendt said.

Here’s what to know about the study results, what’s next for reducing plastic and trash along the river and how you can keep plastic out of important waterways.

What was the top trash found in the Mississippi River?

About 80,000 litter items were logged during the study’s data collection period.

Plastic was the top material found in and around the river, making up 75% of the total trash. Paper and lumber were next at 9%, followed by metal at 7%, glass at 5% and personal protective equipment like masks at 2%.

The top 10 most commonly found items included:

  • 11,278 cigarette butts
  • 9,809 food wrappers
  • 6,723 beverage bottles
  • 5,747 foam fragments
  • 4,239 hard plastic fragments
  • 4,210 paper and cardboard items
  • 3,882 plastic bags
  • 3,640 aluminum or tin cans
  • 3,260 foam or plastic cups
  • 3,149 film fragments
Aerial view shows fog and the Mississippi River.
Fog rises from the Mississippi River near Le Claire, Iowa, on Sept. 18, 2023. Aerial support provided by LightHawk. (Nick Rohlman / The Cedar Rapids Gazette)

Other notable finds include 825 masks, 480 items of clothing and shoes and 291 pieces of fishing gear.

In an optional survey after logging the trash they found, participants were asked if they cleaned it up. Close to three-fourths said yes.

What do the results tell us about litter habits?

People may not know that cigarette filters are made of cellulose acetate, a type of plastic, Wendt said. They can take up to 10 years to decompose. And cigarettes can also leach other toxic chemicals into the water, according to the report.

Another intriguing finding, Wendt said, was the amount of plastic beverage bottles and aluminum cans found, both of which are recyclable. 

She noted that of the cities that took part in the study, only one of their states, Iowa, has a so-called “bottle bill,” in which people pay a five-cent deposit when they purchase a beverage container and get a five-cent refund if they return the container to a store or redemption center. Bottles were lower down on the litter list in the Quad Cities than in other places.

Legislation like that “is not very popular politically,” Wendt said, “but it does work.”

Some states along the river prohibit local bans of plastic bags, she pointed out.

What’s next for keeping plastic out of the river?

River-wide data collection has wrapped up, but Wendt said the next step is carrying out city-specific projects to reduce plastic pollution.

Those include providing funds to underserved neighborhoods in St. Louis and Baton Rouge so they can pursue what they see as integral to reducing waste, like installing water-filling stations, or developing a curriculum for schools to teach about recycling. 

The mayors’ group will continue to work with the University of Georgia to do a comprehensive assessment of waste management in a few cities, Wendt said, and they’re also planning to work with cities that don’t have recycling programs to provide people a way to recycle.

Wendt maintained that while recycling is part of the solution, it’s not the only solution.

“(The discussion is) moving in the right direction, from ‘Oh, we just need to clean up litter…’ to, ‘Oh, we actually need to reduce the source if we’re going to have any real impact,'” she said.

What can people do to reduce plastic into waterways?

The biggest step people can take is to stop using plastic bags, Wendt said. That also goes for single-use plastic water bottles, she said, except for those who need to drink out of them because of water contamination.

Beyond that, talk to local retailers and see if they’d be willing to ask customers if they want a bag instead of assuming they do, she said, and ask if restaurants could switch to sustainable materials for carryout containers and leftovers. Consumers can push retailers to make changes like this, she said, though she acknowledged it works best when people approach retailers as a group.

Nationally, Wendt said more attention is needed for the role the Mississippi River plays in carrying plastic and trash.

When she attends events about reducing plastic, representatives from coastal cities are often the only ones at the table.

“There’s this whole rest of the middle of the country that needs a little bit of focus,” she said.

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Madeline Heim is a Report for America corps member who writes about environmental challenges in the Mississippi River watershed and across Wisconsin. Contact her at 920-996-7266 or mheim@gannett.com.