38 | New Scientist | 7 December 2019
Plastic
measures
Microplastics now contaminate the food we eat and
the air we breathe. The race is on to see if our health
is at risk, reports Graham Lawton
T
HIS morning I tried to count how many
plastic objects are in my house. I got as
far as the bottom drawer in my kitchen
cabinet – which contained 147 assorted plastic
boxes, lids, cups, straws and disposable
cutlery – then gave up. I had to get to work.
Good job I didn’t get down on my hands
and knees with a microscope to look for really
small bits of plastic, because I would never
have left. By some estimates, the average
household generates 6 kilograms of plastic
dust every year, around 700 billion fragments
known as microplastics. Like snowflakes, every
one is different. Every one may also be harmful.
They aren’t just indoors. “They are
everywhere,” says Dick Vethaak, an
environmental toxicologist at the Deltares
research institute in Delft, the Netherlands.
“In the water, in food, in the air – you are
surrounded by a cloud of them. Everything
is contaminated.” More are created every
day and they will be with us for centuries.
Big plastic debris has been on our radar for
years. Yet this is just the start of something
more insidious. Plastic waste doesn’t
biodegrade but it does break down,
fragmented by wind, waves and sunlight into
ever-smaller pieces. They may be too small
to see, but they are still there, worming their
way into every nook and cranny of the
environment – including our bodies.
This, in a nutshell, is the pervasive problem
of microplastics. But beyond knowing that
they exist and are everywhere, we are woefully
ignorant about them and their potentialimpact on us. That is why the search for
answers is taking on a new urgency.
It is widely assumed that microplastics are
harmful to the environment and ongoing
research suggests that this is a fair assumption.
But when it comes to human health, we are
flying almost blind. “It is only just very recently
that we recognised that we are dealing here
with a health issue,” says Vethaak.
The scale of the plastic waste problem is hard
to wrap your head around. In 2017, a team at
the University of California published a paper
called “Production, use, and fate of all plastics
ever made”. It estimated that since plastics
were invented, we have manufactured around
8.3 billion tonnes of the stuff. Some 5 billion
tonnes of that has been dumped in landfill
or discarded into the environment.
To put that in perspective, the Great Pyramid
of Giza is thought to weigh around 5 million
tonnes. Imagine 1000 Great Pyramids made
of plastic rubbish and you are getting the
picture. And it keeps on coming. Every year
around 4 to 12 million tonnes of plastic waste
enters the marine environment.
Yet it isn’t at all clear how worried we should
be about this deluge. Three state-of-the-art
reports published earlier this year revealed the
depths of our ignorance. The first, by the SAPEA
consortium of scientific academies from across
Europe, reviewed all the available evidence.
On the question of human health, it concluded
that “little is known... and what is known is
surrounded by considerable uncertainty”.
That review fed into an even moreFeatures
8.3
billion
Tonnes of plastic ever produced