Over the past few years, research and conversations on tiny plastic particles have been growing — and now there’s been a development.
Researchers at Columbia University developed a new technology for detecting nanoplastics — the smallest known plastic particles — and used it to test bottled water from three major brands. The average number of plastic fragments they detected was 10 to 100 times greater than previous estimates.
The details of their findings were recently published in the journal Proceedings of the National Academy of Sciences, though they did not reveal the brands of bottled water they tested.
Nanoplastics are fragments smaller than 1 micrometer, or 1/25,000th of an inch. (Larger particles are known as microplastics.)
Columbia’s researchers found 110,000 to 370,000 particles in each liter of bottled water, with 90% of that being nanoplastics and the rest microplastics.
Nanoplastics can be more dangerous than microplastics because they’re so much smaller. They can pass through the intestines and lungs directly into the bloodstream, allowing them to travel to organs throughout the body. Researchers report that nanoplastics can even enter individual cells, and can cross through placentas and enter the bodies of unborn babies.
Researchers have just begun looking at the possible effects of nanoplastics in the body.
There are a few specific types of plastic that researchers identified in this study, which provide some idea of how they end up in bottled water.
One is polyethylene terephthalate (PET). This is what water bottles are made of. Soda bottles, plastic sports drink containers, and bottles of condiments like ketchup and mustard are also made with PET.
Researchers say PET likely ends up within bottled water as bits of plastic slough off when the bottle is squeezed or exposed to heat. It may even get into the water because of the bottle cap, with tiny bits of the plastic being shaved off when it’s repeatedly opened and closed.
Another sort of plastic, polyamide, a type of nylon, was more common than PET. It could be from the plastic filters that distributors use to purify water before bottling.
The majority of the nanoparticles researchers found, though, couldn’t be identified.
Columbia’s research team plans to take a closer look at tap water as well. It’s known that tap water contains microplastics, but much less than what researchers have found in bottled water.