Bottled water is marketed as the very essence of purity. It's the fastest-growing beverage market in the world, valued at US$147 billion per year.
But new research by Orb Media, a nonprofit journalism organization based in Washington, D.C., shows that a single bottle can hold dozens or possibly even thousands of microscopic plastic particles.
Tests on more than 250 bottles from 11 brands reveal contamination with plastic including polypropylene, nylon, and polyethylene terephthalate (PET).
When contacted by reporters, two leading brands confirmed their products contained microplastic, but they said Orb’s study significantly overstates the amount.
For plastic particles in the 100 micron, or 0.10 millimeter size range, tests conducted for Orb at the State University of New York revealed a global average of 10.4 plastic particles per liter. These particles were confirmed as plastic using an industry standard infrared microscope.
The tests also showed a much greater number of even smaller particles that researchers said are also likely plastic. The global average for these particles was 314.6 per liter.
Our test of top bottled water brands from countries in Asia, Europe, Africa, and the Americas was conducted at Professor Sherri Mason’s lab at the State University of New York in Fredonia, near the Canadian border on the frigid banks of Lake Erie.
Mason’s tests were able to record microplastic particles as small as 6.5 microns, or 0.0065 millimeters.
The invisible plastic in bottled water hides in plain sight.
To reveal it, Mason and her colleagues used a special dye, an infrared laser and a blue light like those used by crime-scene investigators.
Under a laminar airflow hood that sucks dust and airborne particles up and away, each bottle was infused with a dye called Nile Red that binds to plastic polymer. The dyed water was then poured through a glass fiber filter.
When viewed through a microscope, under the blue beam of the crime light, with the aid of orange goggles, the residue from each bottle glowed with the flame-colored fluorescence of sometimes thousands of particles.
“This is pretty substantial,” said Andrew Mayes, senior lecturer in chemistry at the University of East Anglia, and developer of the Nile Red method. “I've looked in some detail at the finer points of the way the work was done, and I'm satisfied that it has been applied carefully and appropriately, in a way that I would have done it in my lab.” The study has not been peer reviewed.