Study Finds Human-Created Microplastics in Flathead Lake

Researchers at the University of Montana’s Flathead Lake Biological Station discovered plastic pollution in Northwest Montana’s largest lake. Their study clarifies where the pollution develops and how it can be limited.

By Denali Sagner
The Flathead Lake Biological Station cruises the east shore near Yellow Bay. Beacon file photo

A recent study conducted at the University of Montana’s Flathead Lake Biological Station confirmed microplastic pollution in Flathead Lake, which can be traced back to various types of human activity. The study, while not the first to identify microplastics in Flathead Lake, made important findings surrounding how much microplastic pollution is in the lake and where it originates. The research was led by FLBS visiting researcher Dr. Xiong Xiong from the Chinese Academy of Science’s Institute of Hydrobiology.

According to the study, which was recently published in the journal Environmental Pollution, Flathead Lake carries microplastic pollutants at levels similar to or higher than other lakes in similarly populated areas. Although the levels remain low in comparison to more populated regions, such pollution should still be of concern for residents of the area who drink, bathe and recreate in the water, researchers say. While microplastic levels are not yet high enough to indicate immediate human danger, the new findings are a sign of a growing problem that could have lasting implications for the Flathead’s ecosystems.

The National Ocean Service defines microplastics as “small plastic pieces less than five millimeters long which can be harmful to our ocean and aquatic life.” Once ingested by fish and other animals, they can carry toxins into the aquatic food chain and human food products. Significant concentrations of microplastics have also been found in drinking water systems. In the Flathead’s wide-ranging bodies of water, these pollutants have many origins.

Landfills and plastic waste disposal sites are the largest source of microplastic contamination at the mouth of the Flathead River. Microplastics are often picked up from these sites by water particles and carried into the water system. In addition to waste disposal, the researchers found that the everyday laundry cycle is dumping microplastics into the lake. Much of today’s clothing is made of synthetic fabrics that break into microscopic plastics in the wash. These plastics are transported into the water supply through home septic drain fields and community water treatment plants. Human activities in the water that involve plastic boats, ropes, floats and fishing line can also be cause for concern. Many of these recreational supplies are prone to degrading, adding further microplastics to the water.

“Plastics are a part of our daily lives and they’re embedded in all of the things that we do—in our economy, in our lifestyle. A consequence of that—because plastics don’t degrade—is that they show up everywhere we look,” UM Flathead Lake Biological Station director Jim Elser told the Beacon.

Despite these concerning findings, the researchers say there are many actions that can be taken to remedy increasing levels of pollution.

On an individual scale, adopting in-line washing machine filters, reducing one’s consumption of synthetic fiber materials and limiting single-use plastics can help decrease pollution. The study also suggests larger reforms such as improving plastic waste disposal procedures, strengthening education on the dangers of plastic pollution and improving wastewater treatment systems.

Earlier this month, the U.S. Interior Department announced that it will phase out single-use plastics at national parks and other public lands over the next ten years, a move that will curb plastic consumption in Northwest Montana. While the announcement addresses certain pollution sources mentioned in the FLBS research, the policy is limited to enforcement on federal lands.

To ultimately see larger scale changes, Elser said, “we need to start switching away and using less plastic.”

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