New research has found plastic fibres in drinking water.

Samples taken from more than a dozen countries found a 500ml glass of tap water contained on average four tiny plastic fibres.

Analysis by environmental investigators Orb Media and the University of Minnesota School of Public Health showed 72% of samples taken in the UK were contaminated.

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The study of 150 water samples has yet to be published in a scientific journal.

Dan Morrison, the lead investigator, told Sky News that precautions were taken to avoid accidental contamination of the water samples.


"The source is a fantastic mystery," he said.

"It could be that they are fibres from synthetic clothes and that the friction of daily life sends them into the air and they are then deposited into reservoirs, lakes and streams that feed cities as tap water.

"Another possibility is that when you wash synthetic clothes they shed a large number of microscopic fibres and waste treatment plants don't catch them all.

"This water may be picked up by a downstream community for their water supply. But these are guesses, nobody knows."

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Microplastic particles are widely found in the ocean and consumed by marine animals.

They are known to be in the human food chain, with unknown consequences for our health.

Professor Richard Thompson of Plymouth University, who was one of the first scientists to identify microplastics in the environment, said important questions remained over the drinking water research.

He said: "There is no evidence that any pieces described as plastic were formally identified, that there was any forensic analysis.

"That's quite an involved laboratory procedure to confirm the type of plastic. That data appears to be missing."

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He added even if the fibres were plastic, contamination levels were low and the water was safe to drink.