Under the microscope their colors vary. They float in oceans and rivers, and they were recently found as high as the French Pyrenees.

Microplastics could be everywhere.

To establish how much so, Environment Montana and a team of interns this spring plan to test 50 waters across Montana for microplastics. The results will be posted this fall with the magnified images of their findings.

“I think there's an assumption that plastics aren't a Montana problem, because we're not a heavily populated state, and we're not a coastal state,” said Skye Borden, state director of Environment Montana, who plans to lead the testing. “I don't think we've done enough research to decide it's not our problem yet. I don't think we can just assume that right now.”

Several years ago, Adventure Scientists launched a pilot survey of five sites along the Gallatin River and found microplastic particles in each of them. The study gave rise to the Gallatin Microplastics Initiative – a wider research effort to study plastics in the Gallatin watershed and potential solutions.

“They did find a number of microplastics from a very Bozeman problem,” Borden said. “Most of the microplastics in that watershed were coming from the wastewater facility, from people washing their fleece jackets. Right now, we don't treat microplastics as a priority pollutant.”

Microplastics derive from other sources as well, including plastic bottles and bags, cosmetics and even some toothpastes. They end up as beads, filaments or granules smaller than a pencil eraser. By 2050, scientists believe, plastics will outweigh all the fish in the ocean, posing great risk to marine life and the food it produces.

But plastics have also made their way into inland environments, including Montana's watersheds. Borden will use a sampling and processing guidebook produced by the Mississippi State University extension office to inform her research.

“A number of people have been using that guide to test coastal waterways, and people are starting to test the interior using this guide as well,” said Borden. “I'm going to be using that protocol so we can compare apples to apples for what other people have been doing.”

Borden, based in Missoula, plans to test 50 different locations across the state starting in May. That includes crowded access sites like Whitefish city beach and smaller streams in eastern Montana.

The samples will be siphoned through filter paper and examined under a microscope. Borden's team will also produce digital images of each sample and place the results online this fall.

“Generally speaking, when you look for plastic, you find it,” she said. “We've designed our study to include places where you might expect to find plastic, like the main stem of the Yellowstone River, and places you wouldn't, like the North Fork of the Flathead.”