Due to COVID-19, conversations have stalled on Logan’s plastic bag ban, but a Utah State University professor took advantage of the lull to share her research on microplastic accumulation.
Microplastics, as the name suggests, are tiny, broken-down pieces of larger plastics known to accumulate in wastewater, rivers and oceans. According to a serendipitous find by Janice Brahney, an assistant professor of watershed sciences at USU, they accumulate and can be transported through the atmosphere, as well.
Over 14 months, Brahney examined 11 national park sites and wilderness areas weekly for particles distributed through rainfall and monthly for those deposited in dry conditions. The team estimated that more than 1,000 tons of microplastics are deposited onto protected lands in the Western U.S. each year, “equivalent to more than 123 million plastic water bottles.”
Brahney meant to study how dust and microscopic nutrients travel through space and impact agriculture and the environment. But when she examined the samples under a microscope, she was shocked to find “a lot of very brightly colored bits of material.”
“I realized that I was looking at plastic deposition,” she said, “and that it was in almost every sample.”
And while microbeads and glitter from the makeup industry have come under fire for contributing to microplastic accumulation in wastewater, Brahney said only about 30% of her samples were particles like microbeads, and they were much smaller than those found in cosmetics. Instead, she said they are most commonly found in paint additives.
But the majority of her plastic samples were fibers, “and most of those fibers were clothing fibers.”
Synthetic fibers in clothing break down to form microplastics and enter the environment in several ways. In addition to clothes shedding fibers simply by wearing them, the fibers can also enter wastewater when washed and be directly vented into the atmosphere when machine-dried.
“The particles, for the most part, were hard to ascribe to a particular source because they were all identified as very common-used plastics and for a variety of different reasons,” Brahney said. “And those are likely derived from all of our waste that has been improperly managed and broken down into smaller and smaller pieces in the environment.”
At different sites, the fibers and particles varied in size, which Brahney and her team used to determine how far they had traveled before falling out of the atmosphere.
“With rain, the sizes that we were looking at were much bigger,” she said. “And so I’m sure it’s very intuitive to think that smaller particles can travel farther, whereas larger particles will fall out of the atmosphere quicker.”
Brahney said the initial source of microplastics into the environment tends to be from cities. While “wet samples,” or rain-deposited, tended to be larger and therefore hadn’t traveled as far, microplastics can break down and be transported thousands of miles away through air masses and large-scale climate and weather patterns as seen in the “dry samples.”
“Higher-elevation sites had more plastic and higher deposition rates,” she said, though the particles found tended to be smaller. “That tells us that the plastics are moving higher up in the atmosphere.”
It can take thousands of years for plastic to break down, though it can never really decompose, just break down into smaller pieces, according to experts, including Brahney. And when China stopped accepting plastic recycling from the United States, many places — such as Logan and the rest of Cache County — stopped accepting 3-7-type plastics, resulting in more plastics entering landfills.