Tiny creatures that swim in Flathead Lake and filter out algae have trouble when they ingest microplastic.

The tiny particles can poison them, or the edges can aggravate their digestive tracts. If those things happen, the little crustaceans and zooplankton aren’t cleaning the water.

“We like in Flathead Lake that our water is so clear,” said Jim Elser, director of the Flathead Lake Biological Station of the University of Montana. “If we impair our filter feeders, the lake might not be so clear anymore.”

Microplastics are pieces of plastic that are so small, they can’t be seen by the naked eye. In 2018, a visiting researcher from the Chinese Academy of Science’s Institute of Hydrobiology led a study of microplastics in the lake, and the journal Environmental Pollution recently published the work, “Microplastics in Flathead Lake, a large oligotrophic mountain lake in the USA.”

“It looks quite clean, but if this clean lake is suffering from plastics, I want to check that,” said Xiong Xiong at the start of his study, according to a statement provided by UM. “I think people think (plastic pollution) is more serious in the ocean, but many people live inland, and we need the freshwater. It may affect our daily life more directly than the plastic in the ocean.”

Previously, Xiong and Elser studied microplastics in the Yangtze River, and then, the Chinese scientist headed to the Flathead to learn about microplastics in freshwater in a relatively unpopulated region. (Elser said his colleague’s name, Xiong, means “bear,” so it made sense for him to have a relationship with the UM Grizzlies.) Microplastics exist at the top of Mount Everest and at the bottom of the ocean, so Elser said it wasn’t a long shot to expect concentrations in the lake.

“This was the first real comprehensive look in Flathead Lake, so we weren’t surprised to find them,” Elser said. “We were concerned to find them.”

The study showed microplastics fall into the lake from the sky through the air and rain and snow, and they arrive through rivers, according to UM: “At the mouth of the Flathead River, the biggest source of microplastics is most likely from plastic waste disposal, which in Flathead County is primarily landfill rather than recycling. Although landfills located in the Flathead Watershed are not open pit, microplastics are mobilized via leachate (water that picks up contaminants) and via the soil of the landfill when winds carry away dust.”

Flathead Lake is the largest body of freshwater in the western U.S. outside of Alaska, according to a fact sheet from the Flathead Lake Biological Station. It’s known for its water quality, but the clean and clear lake also faces threats.

Of those, aquatic invasive species have been one of the most publicized in recent years, and Elser said they remain the biggest risk to the lake, with the zebra and quagga mussels at the top of the list. However, he also said the State of Montana and Confederated Salish and Kootenai Tribes have done an impressive job of implementing effective campaigns against those risks.

Nutrient pollution is another high risk, he said, especially related to failing septic systems on the lake. He said many of those systems are aging, and they may become problematic in the near term if they don’t receive some attention.

“They are mostly going to contribute to nearshore algae blooms that would be unsightly,” Elser said. “Probably, that’s another one that we should be concerned about.”

For now, the levels of microplastics aren’t “alarmingly high,” but Elser also said the biological station doesn’t regularly monitor microplastics, like it does plankton and nutrients, and it might be time to start.

“Definitely, microplastics is something that we should consider adding to our program,” Elser said.

In the meantime, though, he said people can take action to decrease the presence of microplastics in the environment. For one thing, he said, littering contributes to the problem, so solid waste management is part of the solution, or getting trash where it belongs, and also ramping up plastic recycling.

Some microplastics come from clothing, and people can install filters on their washing machines that catch the particles. Additionally, he said manufacturers that make fleece products could install them since most of the particles are released in the first couple of washes of a textile.

He also said people can also choose cotton and wool over synthetic materials if they don’t need high performance gear. They can cut down on single use plastics, such as utensils from fast food restaurants, and also think twice before buying water from the grocery store.

“People are switching to refillable bottles, which is good,” Elser said.

Of course, he said some problems can’t be solved at the individual level. For example, some of the microplastics land in the lake from masses of air and dust flowing from all different parts of the country, and that means change will require action from governments at all levels, even internationally, and action requires awareness.

“This isn’t just our problem,” Elser said. “It’s a global problem.”

According to UM, Xiong and his research team said more studies are needed to better understand and address the microplastic problem, not only in the Flathead but throughout the world.

But on the lake, the issue may be especially tangible. Microplastics can become a problem for people who want to cast a line for a fish or paddle through clear water, Elser said: “Choking the filter feeders with microplastics won’t help your fishing any.”

UM noted additional study authors include Flathead Lake Biological Station research scientist Tyler Tappenbeck and Chinese Academy of Sciences researcher Chenxi Wu.

Republished with permission from the Daily Montanan, by Keila Szpaller