It's "Raining Plastic” In America’s Rocky Mountains


The issue of plastics in both urban and remote settings is "ubiquitous," according to researchers. Claudine Van Massenhove/Shutterstock

Microplastics raining from the sky have been recorded on top of some of the world’s highest peaks, according to a new study titled It Is Raining Plastic conducted by the US Geological Society.

Operating under a national environmental monitoring network, scientists collected rainwater samples across the State of Colorado at six sites in 2017 in plastic bag-lined buckets before filtering, drying, and weighing the samples, which were then manually analyzed under a microscope with a magnification of around 40 times. Multicolored microscopic plastic fibers were found in over 90 percent of the filters with the most commonly observed colors being blue followed by red, silver, purple, green, and yellow, respectively. More plastics were found in urban sites than isolated mountains, but the authors note that the plastic issue is “ubiquitous and not just an urban condition”.


"We noticed there were far more fibers in the urban monitoring sites than in the foothills, but even in the Rocky Mountain National Park at a site that is in a remote wilderness area 3.5 miles from the nearest parking lot only accessible by foot, we saw microplastic particles rained out from the atmosphere," Gregory Wetherbee, USGS Research Chemist and study author, told IFLScience.

Photomicrographs of plastics collected at the NUANC NTN subnetwork, Sugarloaf, and Loch Vale sites in Colorado. Explanation of labels: CO06, site identification; 2-28-17, month-day-year; 40X, magnification; Red outline indicates Loch Vale samples. USGS

Wetherbee says his team removed clear, white, and opaque plastics from the sample collection that might have been cross-contaminated from his team's sampling apparatus. Additionally, the study notes that estimating how much plastic is really found in our atmosphere and mountaintops is “tedious, expensive, and has large inherent error”. Plastics are too small to weigh or reliably estimate and counting plastic fibers under a microscope and multiplying it is time-intensive. Even so, Wetherbee says that the amount of plastics found was surprising.

"It became pretty clear to me that the particles that we’re seeing in the park must have been transported some distance. It’s unclear how far they were transported or if they were from the urban area or from a much greater distance, but the frequency of detection of the particles in the park was very high," he said. 

The findings bring up more questions than answers about how much plastic is infiltrating Earth’s air, water, soil, and everything else on the planet. Another study published earlier this year found microplastics in high densities atop the Pyrenees, a remote mountain range nestled between France and Spain. More than 360 pieces of microscopic were counted in each square meter of land every single day. A similar study published this week found evidence of plastic is being transported tremendous distances and accumulated in arctic floes and mountaintops. 


"Plastic is a ubiquitous part of the environment now. There is more plastic in the environment than what meets the eye. These plastic materials can be transported great distances into remote areas where there is little or no source for these materials," said Wetherbee. "The other thing it tells us is that we have a long way to go to learn how to measure these materials in the environment in a quantitative and meaningful way."

It begs the question: what kind of effect does plastic have on the ecosystem? 

Plastics have been found in nearly every corner of the world, from the furthest reaches of the Arctic to the deepest parts of the world’s oceans and even on your dinner plate at home. It is unclear how the consumption of microplastics affects health as the study of plastics is still a relatively new field of research.


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