Tiny flakes of plastic discovered high in the French Pyrenees may have been carried by winds more than 4,500 kilometres, researchers believe.
Microplastics – defined as small pieces of plastic less than 5mm in size – were discovered at a star-gazing observatory nearly 3,000 metres above sea level in southern France, according to the study in the journal Nature Communications.
Researchers used meteorological modelling tools to suggest that the flakes may have come from as far away as the US and Canada carried by winds through the layer of atmosphere above the clouds, known as the free troposphere.
The findings by researchers from the UK and France are significant as they suggest that even the world’s most pristine, remote and uninhabited sites could be affected by the use of plastics that could potentially carry viruses and chemicals.
How far the plastic flakes can travel depends in part on the altitude they reach, with faster moving winds higher in the atmosphere.
Most research about the spread of plastic has focused on ocean-borne movements but this study is the latest to indicate that plastic can travel huge distances. Dust that has entered the free troposphere has been recorded to circuit the world.
A study of plastic fragments in London from 2020 has suggested that plastics had been found that originated nearly 9,000km away. Other studies have shown large amounts of plastic flakes in snow collected in icebergs and the Arctic.
The researchers from the universities of Strathclyde and Birmingham in the UK and Grenoble and Toulouse in France suggested that the source of the plastic was North America, western Europe and North Africa, based on wind, humidity and other weather patterns.
The study found that the most common form of plastic found at the Pic du Midi observatory was polyethylene, invented in the 1950s and one of the most widely produced plastics in the world with tens of millions of tonnes produced every year.
The vast production of plastics and the failure to dispose of it properly has left the world with vast volumes of plastic that might only be used for a few minutes but could take 400 years to break down.
The researchers said further study using modelling could help to identify the sources of the plastic pollution. It could potentially have come from areas such as North Africa, Spain, Portugal, France, the UK and Ireland and as far away as Canada, they said.
“These findings have implications for remote areas, transporting this new contaminant (and potential pollutant) far beyond its source location,” said the study.
“It also indicates a potential risk to environmental and human health due to the possibility of adsorbed chemicals and bacteria/virus being transported long distances prior to deposition in pristine locations and areas vulnerable to exotic chemicals and bacteria/virus.”
One of the authors of the paper, Steve Allen, said the study added to a small body of work on the impact of plastics spread by the wind.
"We need a lot more research and, given the potential human health implications from breathing this material, we need it fast," he said.