USU Professor Studying How Plastic Moves Its Way Through Bear River System

In a study published in 2020, Janice Brahney, Utah State University associate professor in the Department of Watershed Sciences, made a startling discovery: microplastic particles are widespread in the Earth’s atmosphere. These tiny particles of plastic, ranging between 1 micrometer and 2.5 millimeters, are being deposited by the wind into even the most remote places in the Western United States.

Brahney’s curiosity led her to wonder about USU’s own backyard, the Cache Valley mountains and the Logan and Bear rivers. Taking an atmospheric deposition sampling unit out into the mountains, Brahney discovered that there were indeed plastic particles in the Logan atmosphere, and these were being deposited into these mountain ecosystems. Brahney and a team of other researchers are looking to answer several resulting questions: How much plastic is out there; How much is moving through freshwater ecosystems; How does the quantity and polymer type differ between different types of land groups (remote, recreational, agricultural, urban), and ultimately, how does this affect the ecosystem?

“We want to ultimately quantify how much plastic is coming from the Bear Logan system and being transported to the Great Salt Lake,” Brahney said.

One of the many questions Brahney and her team are trying to answer is what types of plastics are entering the ecosystem and how they are entering. Plastic can come in the form of fibers from clothing, particles from broken-down plastic such as bottles and grocery bags, and beads of plastic, and broken down vehicle tires. These particles can be deposited into the river itself or fall in the catchment and enter the waterway through rainfall, snow melt or from animal movement.

“We are looking at the different sources of microplastics in this river system and also the characteristics of the microplastics that make it into the river,” said Macy Gustavus, a USU research assistant and master’s student in the Department of Watershed Sciences. “We are looking at the colors, shapes, sizes, polymer types and pretty much anything that defines a piece of plastic. We are cataloging it and seeing if these characteristics are associated with different types of sources. Do urban areas have more fibers than beads? Do remote areas get smaller plastics because those might travel more advantageously through the environment?”

The team took samples from the river throughout all of 2021, starting in January.

“We wanted to see if there are changes in microplastic concentrations and characteristics throughout the entire year,” Gustavus said.

The study is in its early stages and the data are just being interpreted. However, preliminary findings of the data are showing that plastic is present in the Logan Bear River system. Urban areas like Logan itself have higher concentrations of microplastics in the air, but these concentrations seem to fluctuate more than the concentrations of microplastics that are found in more remote areas. Also, the amount of plastic found in the water systems is higher during times where water is moving faster, such as during rainfall or snowmelt, as opposed to when water levels are steady and slow moving. Another finding is that plastics are also being found inside organisms in the river, such as snails, fish and other wildlife, who mistake the plastics as food.

Brahney and her team still have questions that they are looking to answer. And with these answers, more questions are popping up. Brahney hopes to continue looking at the effect of plastic on wildlife and the potential health impacts that plastic getting inside these organisms can have.

“Right now we are trying to understand not just are they consuming microplastics but where are they ending up within their system,” Brahney said. “Is it just in their stomach content, or is it in their liver? How is the plastic being consumed and moving through the food web, and ultimately what are the consequences of it?”

An early spoiler: it’s there.

“The plastic is there,” Brahney said. “It’s in the liver. It’s in the stomach lining and stomach contents. It’s in everything that we’ve looked at. Their presence is concerning.”

Just how concerning remains to be seen.