But the first study on microplastics in Everest, conducted in 2019 by scientists on an expedition of the National Geographic and Rolex Perpetual Planet campaign, shows that this material can be found up to 8,840 meters, albeit with higher concentrations in the base camp located at 5,364 meters.
Scientists came across microplastics on the world's highest mountain, near the summit of Mount Everest, where oxygen was insufficient and called the "death zone". To arrive at their findings, the researchers constructed time series of glacier mass-change measurements based on modern and historical satellite images of Mt. Everest and the surrounding glacial valleys stretching back 56 years.
"Subsequently", the authors write, "it is highly suspected that these [microplastics] originated from performance clothing and equipment used by climbers and trekkers rather than existing macroplastic debris".
Nepalese authorities say that the number of visitors to Sagarmatha National Park, where Everest lies, has roughly tripled in the past 20 years. This increasing number of tourists inevitably comes with a growing amount of rubbish left behind on the mountains.
"Microplastics haven't been studied on the mountain before, but they're generally just as persistent and typically more hard to remove than larger items of debris", lead author Imogen Napper, a National Geographic Explorer and marine scientist at the University of Plymouth, said in a statement on Friday.
Prior research, for example, has found one simple coat of polyester clothing could release a billion microplastics per year. They aimed to determine whether there was plastic on the mountain and the type of plastic there.
"Right now the problem is like an overcrowded bathroom, and instead of continually mopping the floor, we just turn off the tap".
While the research found fewer microplastics in the water surrounding Mount Everest, it's entirely possible that even these lower concentrations could be consumed by locals who reside downstream.
Scientists are only now beginning to measure the damage to wildlife and potential impacts on human health.
"In general, tourism destinations are always known for pollution, whether it's microplastics or macroplastics".
As a result, researchers have suggested the fibers - the highest of which were found in samples from the Balcony of Mount Everest, 8,440 meters above sea level - could have fragmented from larger items during expeditions to reach the summit.
"These are the highest microplastics discovered so far", she added "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".