INVASION OF THE PLASTIC PEBBLES
FEARS FAKE STONES COULD HARM ECO SYSTEM
OFTEN they hide in plain sight, crunching beneath feet as people stroll along the pebbled beaches of west Wales.
Litter cleaners frequently miss them because they look just like the real thing.
“It’s only when you pick them up, and feel how light they are, that you realise they are not stones at all,” said Hilary Rowlands, a founding member of Tywyn Beach Guardians in Gwynedd. They are in fact “fake” plastic pebbles and there’s anecdotal evidence they are washing up from the Irish Sea in ever greater numbers.
Environmentalists say this newest and most curious form of plastic pollution could enter food chains as they break down into microplastics.
Known as pyroplastics, the “stones” are thought to form when pieces of plastic are melted or burnt and thrown into the sea, where they are slowly weathered grey and smooth as they float on long ocean voyages. Hilary said they are commonplace around the mouth of the Dyfi estuary, disgorged onto beaches by storms. She’s also found variants, termed plasti-glomerates, which are created when burnt plastic fuses with rock, commonly when people light fires on beaches.
“There’s not a single beach I’ve combed where I haven’t come across them,” she said. “Sometimes they are covered in oil or impregnated with the toxins that come from burning plastic.
“It’s all dangerous, both to the environment and the marine life. The longerterm concern is that they will break down into microplastics and threaten marine food chains.”
First to describe pyroplastics in Britain was Dr Andrew Turner, an environmental scientist at the University of Plymouth. In Cornwall, some beachcombers had been uncovering thousands of plastic rocks and pebbles.
Using X-ray and infrared spectroscopy, Dr Turner discovered they comprised of polyethylene and polyproplyene, two of the most common forms of plastic. More analysis showed they contained lead and, usually, chromium.
Dr Turner surmised these were the traces of lead chromate, a compound once added to plastics to colour them red or yellow. He was surprised just how well the plastic impostors blended in with their surroundings.
“When we have university open days, I show visitors 15 boxes of stones and ask them to pick out the one that contains plastic stones,” he said. “Without touching them, very few people get it right.”
It is for this reason that identifying the scale of the problem is fraught with difficulty. Given that Dr Turner has received samples from around the world, it’s likely to be a global problem. And despite recent discoveries, it’s probable many pyroplastics are decades old, perhaps originating from the now banned practice of burning plastic at sea. “But in some countries plastic is still burnt and cast into the sea to get rid of it,” he said.
Even harder to spot on beaches are another, more insidious form of plastic pollution. These are nurdles, the tiny lentil-shaped pellets that are the raw material for almost all plastic products. As they weigh a fraction of a gram, they are easily spilled, quickly entering watercourses and marine systems.
Dawn Thomas, Living Seas awareness officer at North Wales Wildlife Trust, said pyroplastics and nurdles both present longterm threats, yet tackling the problem is not easy.
“We have been seeing it (pyroplastic) looking just like pebbles and stones on beaches and that’s part of the problem, as it can get overlooked on a beach clean,” she said. “Nurdles are smaller and bite-sized for our wildlife – some have even been found to be attracted to the bacterial coating they collect.
“Again, they are difficult to collect as they’re so small and often translucent.”
While the idea of Wales’ beaches turning artificial sounds fanciful, some people worry about the long-term impact on tourism if plastic pebbles keep rolling onto shorelines.