It pointed out that there are no regulations on microplastics or a scientific consensus on how to test for them, and it also highlighted a much smaller German study previous year that found plastic particles in single use bottles but not above a statistically significant amount.
Thought to be the largest study of its kind, scientists examined more than 250 bottles of water from 11 different brands from around the world and found "almost all were contaminated to some degree".
The particles were detected using Nile Red dye, which binds to plastic polymer.
Even smaller particles were more common - averaging about 325 per liter.
"Our love affair with making single-use disposable plastics out of a material that lasts for literally centuries - that's a disconnect, and I think we need to rethink our relationship with that", says Prof.
The tests were carried out at the State University of NY in Fredonia as part of a project involving original research and reporting by the US-based journalism organisation Orb Media.
"What we do know is that some of these particles are big enough that, once ingested, they are probably excreted but along the way they can release chemicals that cause known human health impacts". The brands affected include Nestle Pure Life, Dasani, Gerolsteiner, E-Pura, Evian, and Aquafina, to name just a few - again, with huge average microplastic variations across the board.
The water tested was purchased in the U.S., Kenya, China, Brazil, India, Indonesia, Lebanon, Mexico and Thailand, and represented a range of brands across several continents. They examined over 250 bottles of water from 11 leading national and global brands purchased in nine different countries.
Bottled water is not alone. Of 259 bottles tested only 17 were free of plastic and concentrations were as high as 10,000 pieces per litre, roughly twice as much as researchers found in tap water in an earlier study. He warned from consuming water in a plastic bottle that has been kept in high temperatures or forgotten in a auto for days since temperature and plastic combination could produce carcinogenic particles.
The fibres were anywhere between 0.1 millimetre and 1.5mm in size.
Microbeads - tiny plastic beads found in some beauty products that were banned in the U.S.in 2015 - are another source of plastics in water.
The process was praised by government consultants as being "well conducted" research.
Brazilian brand Minalba told Orb that it abides by all quality and security standards required by Brazilian legislation.
"Consumers can remain confident that bottled water products, like all food and beverages, are strictly regulated by the U.S. Food and Drug Administration and, thus, are safe for consumption", the statement reads.
Brands Biserli and Wahaha did not respond to Orb's request for comment.