To assess the number of nanoparticles in bottled water, the researchers used a chemical analysis technique called Stimulated Raman Scattering, recently invented by one of the study’s co-authors. The samples were probed with two lasers tuned to resonate with certain molecules, and a computer algorithm was able to determine which particles they were.
The researchers tested three leading bottled water brands, but did not want to name them because they believe all bottled water contains nanoplastics, so it would not be fair to single them out.
According to the study, 110,000 to 370,000 particles per liter were detected in bottled water, and 90 percent of these particles were nanoplastics and the rest microplastics.
The particles were mostly made of nylon (polyamide plastic) and presumably came from plastic filters used to purify water. The second most common particle was PET (polyethylene terephthalate), which is what the bottles themselves are made of, and was released into the water by squeezing the bottle. Other plastics may have entered the water when the bottle cap was unscrewed or screwed back on.
The next investigation of the research team is devoted to tap water, which also contains microplastics, but not in the same amount as in bottled water.
Cover image: illustration
