(CN) – A new study led by a nonprofit journalism group found that more than 90 percent of several top brands of bottled water were contaminated with tiny pieces of plastic.
“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,” according to a release about the research by Washington, D.C.-based Orb Media.
The nonprofit journalism organization tested 11 top bottled water brands from Asia, Europe, Africa and America at the State University of New York and found that 93 percent showed some level of microplastic contamination.
Professor Sherri Mason spearheaded the research, in which each bottle was infused with a dye called “Nile Red” that binds to plastic polymer before being placed under a laminar airflow hood that removes dust and airborne particles. The dyed water was then filtered through glass fiber.
Under a microscope and blue light, researchers used orange goggles to observe the glowing residue of the particles from the bottles and recorded some as small as 6.5 microns, or 0.0065 millimeters.
“Some of the bottles we tested contained so many particles that we asked a former astrophysicist to use his experience counting stars in the heavens to help us tally these fluorescing constellations. Sizes ranged from the width of a human hair down to the size of a red blood cell. Some bottles had thousands. A few effectively had no plastic at all,” according to the study.
Research revealed a global average of 10.4 plastic particles per liter for particles in the 0.10 millimeter size range. An industry standard infrared microscope was used to confirm the particles were plastic.
Tests also revealed a higher number of even smaller particles that are also likely plastic, according to researchers. A global average of 314.6 particles per liter was found.
American bottling company Nestle Pure Life had the highest with a maximum of 10,390 particles per liter and Italian company San Pellegrino had the lowest with a maximum of 74 particles per liter.
According to the study, Nestle conducted its own testing of six bottles from three locations following an inquiry from Orb Media and its head of quality Frederic de Bruyne said the results “showed between zero and five plastic particles per liter.”
He also argued Professor Mason’s testing failed to include a step to remove biological substances therefore “some of the fluorescing particles could be false positives – natural material that the Nile Red had also stained.”
None of the other companies agreed to publicize their plastic contamination test results, according to Orb Media.
Up to 90 percent of microplastic particles consumed by humans can travel through the gut without a trace, according to a 2016 report on plastic in seafood by the European Food Safety Authority cited in the bottled water study. Others might get lodged into the intestinal wall or make their way through the body another way.
“Based on what we know so far about the toxicity of microplastics—and our knowledge is very limited on that—I would say that there is little health concern, as far as we know,” Martin Wagner, a toxicologist at the Norwegian University of Science and Technology, said in a statement. “I mean, that’s quite logical because I believe that our body is very well-adapted in dealing with those non-digestible particles.”
To remain healthy and hydrated, humans need about two liters of fluids daily, according to the study, and bottled water is the fastest-growing beverage market worldwide, valued at $147 billion a year.
Lisa Lefferts, senior scientist at the U.S.-based Center for Science in the Public Interest, told Orb Media it’s up to the bottling companies to prove themselves.
“Since consumers are paying a premium for bottled water, the onus is on the bottled water companies to show their product is worth the extra cost,” she said.