Tiny pieces of plastic is contained in most bottled water drunk from around the world.
The alarming discovery was revealed in a new study of some of the world’s most popular bottled water brands.
The analysis found more than 90 per cent of bottled water contained tiny pieces of plastic.
The World Health Organisation (WHO) has announced a review into the potential risks of plastic in drinking water in the wake of the analysis.
A previous study also found high levels of microplastics in tap water.
The microscopic plastic particles, which come from sources including cosmetics, clothing and industrial processes, were detected in almost all of the bottles of water tested by researchers at the University of East Anglia.
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”.
Dr Andrew Mayes, who led the study, said: “We are becoming increasingly aware of microplastics in the environment and their potentially harmful effects, but their prevalence in other areas has been much less studied.
“They have been reported in tap water, beer and many other foods, but I think that people will be surprised that almost all bottled water appears to be contaminated too.”
Dr Mayes and his team pioneered a new method of detecting the tiny bits of plastic that can be ingested and accumulate in the body.
He said conventional methods would have been hugely time consuming and prohibitively expensive, although the new technique uses dye to rapidly screen for the particles.
The study is published in the journal Scientific Reports.