Two years ago, scientists reported that plastic pollution has found its way into the Mariana Trench, the darkest, deepest part of the ocean. Now, plastic has officially infiltrated the highest point above sea level: Mount Everest.
Last year, a team of 34 scientists embarked on an icy expedition up Mount Everest to better understand how climate change is affecting the highest point above sea level on Earth. (Mount Chimborazo in Ecuador is the furtherest point away from Earth's core, and Mauna Kea is the tallest from base to peak.) As part of their research, they scooped up snow samples from various spots on the mountain and stored them in stainless steel jars to bring back to the lab for testing, reports Freddie Wilkinson for National Geographic. Upon analysis, the team found that all 11 of the samples they collected had tiny shreds of microplastics imbued in the snow, reports Science News.
"It really surprised me to find microplastics in every single snow sample I analyzed," lead author Imogen Napper, a marine scientist at the University of Plymouth in England, says in a press release. "Mount Everest is somewhere I have always considered remote and pristine. To know we are polluting near the top of the tallest mountain is a real eye-opener."
On average, the team detected around 30 bits of microplastics per quart of water. But they detected the highest concentration of microplastics—119 particles per quart of water—around Everest Base Camp, where climbers spend time resting, regrouping and acclimatizing to the high elevation, reports Damian Carrington for the Guardian.
Most of the fibers were polyester, but they also found significant traces of acrylic, polypropylene and nylon, reports National Geographic. Given the type of plastic and the fact that the highest concentrations were found around base camp, the fibers were most likely shed from the mountaineers' clothing and equipment, such as insulated jackets, tents and ropes.
Microplastic fibers are so small that they are often invisible to the naked eye, but those tiny threads accumulate in massive numbers. A study published in February suggests that a two-pound synthetic jacket sheds 400 microplastic fibers for every 20 minutes of use. Over the course of a year, that jacket can shed a billion fibers, reports National Geographic.
Even the highest points of Everest weren't spared from plastic pollution. Scientists found trace amounts of plastic at an elevation of 27,690 feet, just 1,345 feet shy of the mountain's peak, reports Science News.
"These are the highest microplastics discovered so far," Napper says. "While it sounds exciting, it means that microplastics have been discovered from the depths of the ocean all the way to the highest mountain on Earth. With microplastics so ubiquitous in our environment, it's time to focus on informing appropriate environmental solutions. We need to protect and care for our planet."