Quantcast
Popular
DWalker44 / Getty Images

Tons of Plastic Trash Enter the Great Lakes Every Year – Where Does It Go?

By Matthew J. Hoffman

Awareness is rising worldwide about the scourge of ocean plastic pollution, from Earth Day 2018 events to the cover of National Geographic magazine. But few people realize that similar concentrations of plastic pollution are accumulating in lakes and rivers. One recent study found microplastic particles—fragments measuring less then five millimeters—in globally sourced tap water and beer brewed with water from the Great Lakes.


According to recent estimates, more than 8 million tons of plastic enter the oceans every year. Using that study's calculations of how much plastic pollution per person enters the water in coastal regions, one of us (Matthew Hoffman) has estimated that around 10,000 tons of plastic enter the Great Lakes annually. Now we are analyzing where it accumulates and how it may affect aquatic life.

No Garbage Patches, but Lots of Scrap on Beaches

Plastic enters the Great Lakes in many ways. People on the shore and on boats throw litter in the water. Microplastic pollution also comes from wastewater treatment plants, stormwater and agricultural runoff. Some plastic fibers become airborne—possibly from clothing or building materials weathering outdoors—and are probably deposited into the lakes directly from the air.

Sampling natural water bodies for plastic particles is time-consuming and can be done on only a small fraction of any given river or lake. To augment actual sampling, researchers can use computational models to map how plastic pollution will move once it enters the water. In the ocean, these models show how plastic accumulates in particular locations around the globe, including the Arctic.

When plastic pollution was initially found in the Great Lakes, many observers feared that it could accumulate in large floating garbage patches, like those created by ocean currents. However, when we used our computational models to predict how plastic pollution would move around in the surface waters of Lake Erie, we found that temporary accumulation regions formed but did not persist as they do in the ocean. In Lake Erie and the other Great Lakes, strong winds break up the accumulation regions.

Subsequent simulations have also found no evidence for a Great Lakes garbage patch. Initially this seems like good news. But we know that a lot of plastic is entering the lakes. If it is not accumulating at their centers, where is it?

Using our models, we created maps that predict the average surface distribution of Great Lakes plastic pollution. They show that most of it ends up closer to shore. This helps to explain why so much plastic is found on Great Lakes beaches: In 2017 alone, volunteers with the Alliance for the Great Lakes collected more than 16 tons of plastic at beach cleanups. If more plastic is ending up near shore, where more wildlife is located and where we obtain our drinking water, is that really a better outcome than a garbage patch?


Average density of simulated particles in the Great Lakes from 2009-2014. Notice that there are no patches in the middle of the Lakes, but more of the particles are concentrated near the shores. Matthew Hoffman / CC BY-NC-ND

Searching for Missing Plastic

We estimate that over four tons of microplastic are floating in Lake Erie. This figure is only a small fraction of the approximately 2,500 tons of plastic that we estimate enter the Lake each year. Similarly, researchers have found that their estimates of how much plastic is floating at the ocean's surface account for only around 1 percent of estimated input. Plastic pollution has adverse effects on many organisms, and to predict which ecosystems and organisms are most affected, it is essential to understand where it is going.

We have begun using more advanced computer models to map the three-dimensional distribution of plastic pollution in the Great Lakes. Assuming that plastic simply moves with currents, we see that a large proportion of it is predicted to sink to lake bottoms. Mapping plastic pollution this way begins to shed light on exposure risks for different species, based on where in the lake they live.

According to our initial simulations, much of the plastic is expected to sink. This prediction is supported by sediment samples collected from the bottom of the Great Lakes, which can contain high concentrations of plastic.

In a real lake, plastic does not just move with the current. It also can float or sink, based on its size and density. As a particle floats and is "weathered" by sun and waves, breaks into smaller particles, and becomes colonized by bacteria and other microorganisms, its ability to sink will change.

Better understanding of the processes that affect plastic transport will enable us to generate more accurate models of how it moves through the water. In addition, we know little so far about how plastic is removed from the water as it lands on the bottom or the beach, or is ingested by organisms.

Prediction Informs Prevention

Developing a complete picture of how plastic pollution travels through waterways, and which habitats are most at risk, is crucial for conceiving and testing possible solutions. If we can accurately track different types of plastic pollution after they enter the water, we can focus on the types that end up in sensitive habitats and predict their ultimate fate.

Of course, preventing plastic from entering our waterways in the first place is the best way to eliminate the problem. But by determining which plastics are more toxic and also more likely to come into contact with sensitive organisms, or end up in our water supply, we can target the "worst of the worst." With this information, government agencies and conservation groups can develop specific community education programs, target cleanup efforts and work with industries to develop alternatives to products that contain these materials.

Reposted with permission from our media associate The Conversation.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Champurrado (Mexican hot chocolate) is a beloved holiday favorite. PETA

8 Festive Vegan Drinks to Keep You Cozy This Winter

By Zachary Toliver

Looking for warm vegan holiday drinks to help you deal with the short days and cold weather? This time of year, we could all use a steamy cup of cheer during the holiday chaos. Have a festive, cozy winter with these delicious options. (Note that you must be 21 to enjoy some of the recipes.)

Keep reading... Show less
Popular
Pexels

For a Happier, Healthier World, Live Modestly

By Marlene Cimons

Gibran Vita makes every effort to get rid of the dispensable. He lives in a small home and wears extra layers indoors to cut his heating bills. He eats and drinks in moderation. He spends his leisure time in "contemplation," volunteering or working on art projects. "I like to think more like a gatherer, that is, 'what do I have?' instead of 'what do I want?'" he said.

Keep reading... Show less
Climate
An underwater marker in front of Cortada's studio helps predict how many feet of water needs to rise before the area becomes submerged. Xavier Cortada

As Miami Battles Sea-Level Rise, This Artist Makes Waves With His 'Underwater Homeowners Association'

By Patrick Rogers

Miami artist Xavier Cortada lives in a house that stands at six feet above sea level. The Episcopal church down the road is 11 feet above the waterline, and the home of his neighbor, a dentist, has an elevation of 13 feet. If what climate scientists predict about rising sea levels comes true, the Atlantic Ocean could rise two to three feet by the time Cortada pays off his 30-year mortgage. As the polar ice caps melt, the sea is inching ever closer to the land he hopes one day to pass on to the next generation, in the city he has called home since the age of three.

Keep reading... Show less
Food
GMVozd / E+ / Getty Images

How to Ferment Vegetables in Three Easy Steps

By Brian Barth

A mason jar packed with cultured or fermented vegetables at your local urban provisions shop will likely set you back $10 to $15. Given that the time and materials involved are no more than five minutes and $2, respectively, one imagines that the makers of cultured vegetables have spent eight years training with fermentation masters in some stone-age village, or that they've mortgaged their house to pay for high-end fermenting equipment to ensure that the dilly beans come out tasting properly pickled.

Keep reading... Show less
Sponsored
Popular
Orangutan in Sumatra. Tbachner / Wikimedia Commons

Norway to Ban Deforestation-Linked Palm Oil Biofuels in Historic Vote

The Norwegian parliament voted this week to make Norway the world's first country to bar its biofuel industry from importing deforestation-linked palm oil starting in 2020, The Independent reported.

Environmentalists celebrated the move as a victory for rainforests, the climate and endangered species such as orangutans that have lost their habitats due to palm oil production in Indonesia and Malaysia. It also sets a major precedent for other nations.

Keep reading... Show less
Oceans
Australia's Great Barrier Reef. Steve Parish/ Lock the Gate Alliance / Flickr / CC BY 2.0

Scientists Discover 'Most Diverse Coral Site' on Great Barrier Reef

Australian scientists have found the "most diverse coral site" on the Great Barrier Reef, observing at least 195 different species of corals in space no longer than 500 meters, The Guardian reported.

The non-profit organization Great Barrier Reef Legacy and marine scientist Charlie Veron, a world expert on coral reefs, confirmed the diversity of the site, also known as the "Legacy Super Site" on the outer reef.

Keep reading... Show less
Sponsored
Renewable Energy
Buses head out at the Denver Public Schools Hilltop Terminal Nov. 10, 2017. Andy Cross / The Denver Post via Getty Images

Why Aren't School Buses Electric? These Coloradans Are Sick of Diesel

By Corey Binns

Before her two kids returned to school at the end of last summer, Lorena Osorio stood before the Westminster, Colorado, school board and gave heartfelt testimony about raising her asthmatic son, now a student at the local high school. "My son was only three years old when he first suffered from asthma," she said. Like most kids, he rode a diesel school bus. Some afternoons he arrived home struggling to breathe.

Keep reading... Show less
Popular
jessicahyde / iStock / Getty Images

Hemp May Soon Be Federally Legal, But Many Will Be Barred From Growing It

By Dan Nosowitz

Senate majority leader Mitch McConnell has, perhaps unexpectedly to those who find themselves agreeing with only this one position of his, been a major force for legalizing industrial hemp. Industrial hemp differs from marijuana in that it's bred specifically to have extremely low concentrations of THC, the primary psychoactive chemical in marijuana; smoke industrial hemp all you want, it'll just give you sore lungs.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!