Nanoplastics are so tiny that, unlike microplastics, they can pass through intestines and lungs directly into the bloodstream and travel from there to organs including the heart and brain.
Bottled water contains tens of thousands of identifiable fragments as well as previously unknown nanoplastics in each container, posing significant health risk, finds a study.
In
recent years, there has been rising concern that tiny particles known as
microplastics are showing up basically everywhere on Earth -- from polar ice to
soil, drinking water and food.
However,
in the study, published in the journal Proceedings of the National Academy of
Sciences, the researchers focussed on nanoplastics -- the spawn of
microplastics that have broken down even further.
For the
first time, the team from the Columbia University in the US could count and identify
these minute particles in bottled water using newly-refined technology.
They
found that on average, a litre contained some 240,000 detectable plastic
fragments -- 10 to 100 times greater than previous estimates, which were based
mainly on larger sizes.
Nanoplastics
are so tiny that, unlike microplastics, they can pass through intestines and
lungs directly into the bloodstream and travel from there to organs including
the heart and brain.
They
can invade individual cells, and cross through the placenta to the bodies of
unborn babies.
"Previously
this was just a dark area, uncharted. Toxicity studies were just guessing
what's in there," said Beizhan Yan, environmental chemist at Columbia
University's Lamont-Doherty Earth Observatory.
"This
opens a window where we can look into a world that was not exposed to us
before."
Using a
technique called stimulated Raman scattering microscopy, which involves probing
samples with two simultaneous lasers that are tuned to make specific molecules
resonate, the researchers tested three popular brands of bottled water sold in
the US (they declined to name which ones), analysing plastic particles down to
just 100 nanometers in size.
They
spotted 110,000 to 370,000 particles in each litre, 90 per cent of which were
nanoplastics; the rest were microplastics.
They
also determined the specific plastics -- polyethylene terephthalate or PET,
polyamide -- a type of nylon, polystyrene, polyvinyl chloride and polymethyl
methacrylate -- all used in various industrial processes.
While
the plastic types the researchers searched for accounted for only about 10 per
cent of all the nanoparticles they found in samples; they have no idea what the
rest are.
If they
are all nanoplastics, that means they could number in the tens of millions per
litre, the researchers said.
But
they could be almost anything, "indicating the complicated particle
composition inside the seemingly simple water sample", the authors wrote.
"The
common existence of natural organic matter certainly requires prudent distinguishment."
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