But the inundation of plastic debris doesn’t come in the form of plastic bags, bottles and straws alone—according to a new study published in Science of The Total Environment, plastic is now taking the form and shape of pebbles that look exactly like the real thing.
The small chunks of plastic are gray, round, and look just like small stones. Yet these new, tiny, rock-like objects are actually a new form of plastic pollution known as pyroplastics.
And because they look so much like real rocks, they’ve probably been all around us for quite some time.
Andrew Turner, an author of the study and environmental scientist at the University of Plymouth, told National Geographic:
“Because they look geological, you could walk by hundreds of them and not notice.”
Pyroplastics are the result of either plastic that’s been heated during production, or by yet-to-be-known processes in our environment. These plastics are subject to the same forces of nature as rocks are, but as they are tossed about with sand in the ocean, they shed microplastic in their wake—and could even be leaching lead into the ocean.
The researchers explain:
“Pyroplastics are evidently formed from melting or burning of plastic and are distinctly different from manufactured (primary and secondary) marine plastics in terms of origin, appearance and thickness.
Since pyroplastics have been retrieved by colleagues from Atlantic beaches in Spain and Pacific beaches of Vancouver, they are not a regional phenomenon, and it is suspected that their distribution may be widespread but that documentation is lacking because of a distinctly geogenic appearance.”
Turner and his colleagues researched 165 chunks of plastic from Whitsand Bay, home to some of the most pristine and protected beaches in England’s southern coast of Cornwall. They also examined similar litter from Ireland, Scotland, and Spain.
After measuring the size and density of the “stones,” they subjected the samples to a range of tests to determine their precise chemical makeup.
The precise origin of these ‘pyroplastics’ and related plastigolmerates remains unclear, but they likely form when plastic debris is melted or burned—either industrially or informally in beach bonfires—and subsequently amalgamates. pic.twitter.com/1h2OSEYD7y
— Ferris Jabr (@ferrisjabr) August 16, 2019
Using infrared spectroscopy and attenuated total reflection, Turner’s team learned that the samples were, indeed, comprised of the two most common forms of plastic—polyethylene and polypropylene.
Alarmingly, when they subjected the pyroplastic stones to X-ray fluorescence, they detected a range of chemical additives—and a high presence of lead, along with chromium.
What this meant to Turner was that the stones contained lead chromate, a common compound that manufacturers add to plastic to color them bright yellow or red. Over the course of years, these colors were dulled down by burning until they became dark gray. Sure enough, when Turner and his team melted down some bright, colored plastics in their lab, those too turned dark gray.
The study notes that the pyroplastics may have undergone informal burning, such as in a campfire, or were burned en masse in an incinerator or similar industrial, organized fashion.
The study noted:
“Evading ready detection due to their striking visual similarity to geogenic material, pyroplastics may contribute to an underestimation of the stock of beached plastics in many cases.”
And what’s most shocking is that many of these plastic pebbles contained wormholes, meaning that the smallest marine animals are eating them and passing lead up the food chain.
These plastic pebbles are also being ground into particulate matter as fine as dust.
https://t.co/7TN0rCyrJ4 via @ScienceAlert
"These small chunks of plastic – called pyroplastics – are created when plastic is heated as part of the manufacturing process, or when pieces of plastic are melted by unknown processes in the environment."
— AmyingHigh (@trashyamye) August 20, 2019
Rob Arnold, a volunteer who worked with Turner and helps conduct beach cleanups, explained to Weather.com:
“It’s these nanoplastics that are our biggest problem, through polluting our marine environment.
The smallest of sea creatures will be ingesting this plastic, which puts it straight into the food chain. As we all know, we are at the top of that chain. This is particularly scary when you consider that these plastics can contain harmful chemicals and heavy metals.”
The study notes that further research is needed to determine precisely how much of this pyroplastic is polluting our shores and releasing dangerous compounds into the environment.
As the team notes in their paper:
“Pyroplastics require their own classification within the umbrella of marine litter, and are a source of finer plastic particulates through mechanical breakdown and a potential source of contaminants for organisms that inhabit or ingest them.”
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