Microplastics have made their way into the Boundary Waters Canoe Area Wilderness, a popular wilderness area in northern Minnesota, according to a University of Wisconsin-Eau Claire research team.
Researchers found microplastics in earthworms, water and soil that they collected this summer from sites within the Boundary Waters, said Todd Wellnitz, professor of biology and the faculty lead on the research project.
“We found 80 pieces of microplastics in one earthworm that we examined,” Wellnitz said. “That blew me away.”
The UW-Eau Claire study is the first research Wellnitz is aware of that confirms the presence of microplastics in the Boundary Waters, the most visited wilderness area in the United States.
Plastics that are less than 5 millimeters in length — about the size of a sesame seed — are known as microplastics. They can come from a variety of sources, including things like synthetic clothing, toothpaste and water bottles.
Significant research has been done on the presence of microplastics in oceans and rivers, but little has been done on plastics in freshwater lakes like those in the Boundary Waters, an area often described as being a pristine wilderness area, he said.
“We’re finding microplastics in the Boundary Waters, and that’s a big deal,” Wellnitz said. “No place is pristine now; microplastics are everywhere. It’s all over the planet and we’re just realizing it.”
The UW-Eau Claire research team, which includes Wellnitz and four UW-Eau Claire undergraduate students, collected earthworm samples during a June visit to the Boundary Waters.
After finding microplastics in the earthworms, the researchers returned to the Boundary Waters in August, this time collecting soil, water, earthworms and crayfish samples.
Samples near campsites
The samples were collected from areas primarily near campsites, said Reed Kostelny, a junior environmental biology major from Appleton, noting that they found the most microplastics in samples taken from the lake closest to the Boundary Waters entry site.
“We know that earthworms do consume microplastics,” Kostelny said of their findings. “Now that we have our early data, we want to know more about the worms and how the microplastics could move up the food chain.”
Since birds, fish and other wildlife consume earthworms, microplastics have likely already entered the food chain in the Minnesota wilderness area, Wellnitz said.
Earthworms are not native to the Boundary Waters area but are brought in by visitors who come to fish the many freshwater lakes found within the area, said Megan Vaillancourt, a senior microbiology major from Stillwater, Minn.
“Fishermen bring the worms in, and the worms are ingesting the plastics we bring in with us,” Vaillancourt said. “That’s a double negative for the area.”
The Boundary Waters Canoe Area Wilderness includes more than 1 million acres of lakes and forested areas along the U.S.-Canadian border. With more than 1,200 canoe routes, 12 hiking trails and 2,000 designated campsites, each year the area attracts thousands of visitors who come to canoe, hike and fish.
“People are passionate about this place,” Wellnitz said of the Boundary Waters, a place the Twin Cities native has visited often during his lifetime. “A lot of visitors come from far way. It’s a beautiful area; people connect to nature here in ways they might not in other places. It just pulls you in.”
Most visitors do embrace the “leave no trace” mantra, a promise to leave nothing behind when they leave the area, he said.
However, microplastics shed easily, so they may be coming from visitors’ clothing, blankets, tarps and other supplies that visitors routinely bring into the Boundary Waters, Vaillancourt said.
Since microplastics are so small that they can’t easily be seen, people have no idea that they are leaving them behind, she said.
Microplastics also can move from place to place via rain or wind, so they likely are entering the Boundary Waters in multiple ways, the researchers say.
An active scholar whose research focuses primarily on aquatics, Wellnitz typically doesn’t study pollution.
However, he became curious about the possibility of microplastics being in the Boundary Waters after reading that significant amounts of microplastics were found in a wilderness area in Montana, not far from Yellowstone National Park.
He brought the potential research project to his students, and several were eager to join the study.
The students will continue their analysis of the many samples they collected during their most recent visit to the Boundary Waters, which will help them identify next steps in their project.
The Blugold researchers also will use their microplastics research findings to raise awareness about the impact humans are having on the world around them.
The students will give talks in area schools, present their research at regional and national meetings and conferences, and write papers to submit to professional science journals.
Hopefully, Thomas Adams, a senior environmental biology major from Eau Claire, said people will think more carefully about how their actions affect the environment after learning that microplastics are present even in a place as remote and protected as the Boundary Waters.
“It’s not surprising that it’s up there, but it’s still sad,” Adams said. “It’s humbling to think about the impact we have on other life. The more attention we can give to what our impact has on someplace like the Boundary Waters, the more we can help people understand that they need to step back and think about what we’re doing.”