Portland researchers track microplastic pollution in Columbia River Basin

Stormwater washing off roads and air pollution from industry are two possible sources of microplastics in the Columbia River Basin such as here at Kalama, Wash. Researchers with Portland State University will spend a year collecting samples to identify the biggest sources of microplastics in the region.

Kristyna Wentz-Graff / OPB

The evidence is mounting: Microplastic pollution is pretty much everywhere.

Studies around the world have found tiny plastic fibers and particles in rivers and lakes, in the ocean’s seafood, floating in the air above remote mountaintops and in freshly fallen snow in Antarctica.

Testing shows they’re making their way into our bodies, too. Scientists recently found microplastics in people’s lungs and blood.

Researchers at Portland State University want to know more about where microplastic pollution is coming from and how it’s getting into our air and water — right here in Oregon.

They recently launched a yearlong effort to track the sources of microplastics in the Columbia River Basin, a massive network of rivers and streams that covers much of the Pacific Northwest. In addition to sampling the air and water to identify the biggest sources of microplastic pollution, they’re working to build a network of people in government, industry and education who might help manage the problem.

Microplastic fibers are less than 5mm and often show up a vivid color under the microscope.

Microplastic fibers are less than 5mm wide and often appear in vivid colors under when viewed under a microscope.

Todd Sonflieth / OPB

Elise Granek, professor of environmental science and management at Portland State University, said she’s hoping to track the “microplastic cycle” from sources such as wastewater sprayed on agricultural fields, cars that wear down and contaminate stormwater, clothes dryers that spew airborne fibers, and wastewater treatment plants that empty directly into rivers.

“In order to manage the microplastics, we need to understand the most significant sources,” she said.

Granek has already done multiple studies on microplastics in the ocean and has consistently found it in marine life such as clams, crabs and oysters.

In 2019, she helped OPB sample for microplastics in rivers across Oregon in a citizen science project that found microscopic plastic fibers and particles in the Columbia, Willamette, Rogue and Deschutes river basins.

Now, Granek wants to take a closer look at how microplastics are getting into those rivers, all of which eventually lead to the ocean.

“We do know there are microplastics at least in our waterways,” Granek said. “But we don’t know what the dominant sources of microplastics into the Columbia River Basin are. People have speculated about a number of sources.”

Granek is working with Heejun Chang, a PSU geography professor, to sample for microplastics in the air and water near likely sources of microplastic pollution.

“We plan to collect samples from a number of different sites that represent urban lands and farmlands, recreational sites, industrial sites, households as well as waterways and motorways,” Chang said. “From the most remote rural area to the most urbanized sections.”

To find out what’s in the air, researchers plan to collect and analyze moss samples. Moss is a natural air pollution monitor because it gets all of its nutrients from the atmosphere. A landmark study in Portland in 2016 used moss to uncover previously unknown hot spots of toxic air pollution around the city.

Chang said they know weather factors like rain can play a role in spreading microplastics, so they’ll be collecting samples over time to compare microplastic pollution across wet winters and dry summers.

“This is looking at the whole microplastic cycle from the source to the transport and destination in a more holistic way,” Granek said. “By sampling both the air and water, we hope to get a better understanding of what the atmospheric contribution is versus what the landscape contribution is.”

To learn how much microplastic pollution is traveling through the air and water, Granek said, they’ll be collecting samples at different distances from suspected sources.

“We’re hoping to understand how far microplastics are traveling from those particular sources,” she said. “So, in a land application of biosolids onto a field, for example, we want to know the amount that gets aerosolized and blown further out. Maybe that’s different than what’s being blown out of the dryer vent.”

The yearlong sampling effort will allow the researchers to map a research project that spans the 258,000 square miles of the Columbia River Basin. Granek and Chang are working with a research team that includes Sarah Carvill, an environmental science instructor at PSU, Nancee Hunter, director of the Center for Geography Education in Oregon at PSU, Jordyn Wolfand, assistant professor of civil engineering at the University of Portland, and Janice Brahney, associate professor of watershed sciences at Utah State University.

Chang said to start working toward solutions, they’re also holding workshops for scientists, wastewater managers, government and industry leaders. This week, they’re launching a class for teachers that will provide them with lessons on microplastics that they can bring to their classrooms.

“Unless we change behaviors and change policy, we won’t be able to solve this issue,” he said.


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