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Depressing New Type of Pollution Has Started Showing Up on Shoreline Rocks
DAVID NIELD
You might think that
plastic pollution on land and sea is
old news by now, but it's taken on a new form we've only just noticed:
Researchers have identified a crust of plastic particles building up on
shoreline rocks.
This 'plasticrust' isn't
just a worrying symbol of the garbage piling up in our oceans. The coating is a
potential threat to the organisms that live and feed on the rocks, and could be
yet another way that plastic is entering the food chain.
Since 2016, a team from the Marine and Environmental Sciences Centre (MARE) in Portugal has been monitoring the build-up of plastics along the shore of the volcanic island of Madeira, assessing their subsequent impact on the local ecosystem.
"[The crusts]
likely originated by the crash of large pieces of plastic against the rocky
shore, resulting in plastic crusting the rock in a similar way algae or lichens
do," marine ecologist Ignacio Gestoso told Jake Buehler at Earther.
The plasticrust looks as
if someone left a chewed up piece of gum or a squeeze of toothpaste on the
rocks. The shape does resemble natural organisms that crust rocks in similar
ways, making this a sober reminder of how plastic is now literally embedding itself
into the environment around us.
It's still early days
for plasticrust research – how it forms, the effects it has – but Gestoso and
his team have now taken several samples of the stuff to investigate further.
Chemical analysis has revealed the crust is indeed made of the widely
used polyethylene,
the material found in plastic bags and food packaging.
And the polyethylene
clinging to the shoreline now covers nearly 10 percent of the rocks' surface,
according to the researchers. The team also found evidence that algae-eating
winkle sea snails (Littorina littorea) were equally at home on
plasticrust as on rock – suggesting they might be sucking up plastic as well as
algae.
Further research should
tell us just how widespread the problem is and how much of an impact this might
have on nearby wildlife, but for now the scientists just want to draw attention
to the problem.
If you're not already thinking about ways of reducing your plastic usage, perhaps the sight of beach-side rocks getting covered in a plastic coating will bring home the seriousness of the problem we've got.
Sadly this isn't the
first time that human-made plastic has tied itself so closely to natural rock –
cast your mind back to 2014 and the discovery of
plastiglomerates, rock-like substances made from melted plastic and
organic debris.
It's now got to the
stage that experts think we're going to leave a noticeable plastic marker in
Earth's sedimentary record – something for future generations to look back on
and realise just how much we rely on plastics at this point in history.
"As a marine
ecologist researcher, I would prefer to be reporting other types of findings,
and not a paper describing this sad new way of plastic pollution," Gestoso
told Earther.
"Unfortunately, the
magnitude of the problem is so huge that few places are free of plastic
pollution."
The research has been
published in Science of the
Total Environment.
