At a Glance

A major study in nine countries found "widespread" contamination of bottled water with microplastics. The researchers found that 93 percent of the bottles tested were contaminated with plastic debris.The study has prompted WHO to launch an health review of microplastics.

The world's leading brands of bottled water are teeming with tiny particles of plastic, a new study says.

According to a summary of the research published Thursday, awith microplastics, which are particles of plastic that are small enough to be ingested. The researchers said the tiny particles of plastic likely were introduced into the water from the bottle, the cap, as well as the bottling process.

The study, led bymicroplastic researcher Dr. Sherri Mason of the State University of New York at Fredonia, tested 259 bottles of water in the UnitedStates, Brazil, China, India, Indonesia, Kenya, Lebanon, Mexico and Thailand. Eleven brands were tested, including Aqua, Aquafina, Dasani, Evian, Nestle Pure Life and San Pellegrino.

According to the study, , includingnylon, polyethylene terephthalate (PET) and polypropylene, which are used to make bottle caps, Agence France Presse reports.

"In this study, 65 percent of the particles we found were actually fragments and not fibers," Mason told AFP. "I think that most of the plastic that we are seeing is coming from the bottle itself. It is coming from the cap. It is coming from the industrial process of bottling the water."

While this study, which was , does not point to microplastics found in the world's oceans, it does point to the dangers associated with the massive amount of plastics humans introduce into theworld each day.

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The study has prompted the World Health Organization to launch an investigation into the , the BBC reports, noting that there is currently no research that concludes that ingesting microplastics poses a danger to health.

"When we think about the composition of the plastic, whether there might be toxins in it, to what extent they might carry harmful constituents, what actually the particles might do in the body – there's just not the research there to tell us," Bruce Gordon,coordinator of the WHO’s global work on water and sanitation, told BBC News. "We normally have a 'safe' limit but to have a safe limit, to define that, we need to understand if these things are dangerous, and if they occur in water at concentrations that are dangerous."

Mason, on the other hand, noted a correlation between plastics and some health issues.

"There are connections to increases in certain kinds of cancer to lower sperm count to increases in conditions like ADHD and autism," said Mason. "We know that they are connected to these synthetic chemicals in the environment and we know that plastics are providing kind of a means to get those chemicals into our bodies."

Previous research initiated by Orb Media also found microplastics in tap water, but to a lesser degree than bottled water.