Microplastic contamination has been found in tap water in countries around the world, leading to calls from scientists for urgent research on the implications for health. Scores of tap water samples from more than a dozen nations were analysed by scientists for an investigation by Orb Media, who shared the findings with the Guardian. Overall, 83 per cent of the samples were contaminated with plastic fibres.
The US had the highest contamination rate, at 94 per cent, with plastic fibres found in tap water sampled at sites including Congress buildings, the US Environmental Protection Agency’s headquarters, and Trump Tower in New York. Lebanon and India had the next highest rates. European nations including the UK, Germany and France had the lowest contamination rate, but this was still 72 per cent. The average number of fibres found in each 500ml sample ranged from 4.8 in the US to 1.9 in Europe.
The new analyses indicate the ubiquitous extent of microplastic contamination in the global environment. Previous work has been largely focused on plastic pollution in the oceans, which suggests people are eating microplastics via contaminated seafood.
A separate small study in the Republic of Ireland released in June also found microplastic contamination in a handful of tap water and well samples. “We don’t know what the [health] impact is and for that reason we should follow the precautionary principle and put enough effort into it now, immediately, so we can find out what the real risks are,” said Dr Anne Marie Mahon at the Galway-Mayo Institute of Technology, who conducted the research.
Mahon said there were two principal concerns: very small plastic particles and the chemicals or pathogens that microplastics can harbour. Microplastics can attract bacteria found in sewage, Mahon said: “Some studies have shown there are more harmful pathogens on microplastics downstream of wastewater treatment plants.”
Microplastics are also known to contain and absorb toxic chemicals and research on wild animals shows they are released in the body. Prof Richard Thompson, at Plymouth University, UK, told Orb: “It became clear very early on that the plastic would release those chemicals and that actually, the conditions in the gut would facilitate really quite rapid release.”
The scale of global microplastic contamination is only starting to become clear, with studies in Germany finding fibres and fragments in honey and sugar. In Paris in 2015, researchers discovered microplastic falling from the air, which they estimated deposits three to 10 tonnes of fibres on the city each year, and that it was also present in the air in people’s homes.
How microplastics end up in drinking water is for now a mystery, but the atmosphere is one obvious source, with fibres shed by the everyday wear and tear of clothes and carpets. Tumble dryers are another potential source, with almost 80 per cent of US households having dryers that usually vent to the open air. Plastic fibres may also be flushed into water systems, with a recent study finding that each cycle of a washing machine could release 700,000 fibres into the environment. Rains could also sweep up microplastic pollution, which could explain why the household wells used in Indonesia were found to be contaminated.
Almost 300m tonnes of plastic is produced each year and, with just 20per cent recycled or incinerated, much of it ends up littering the air, land and sea. Mahon said the new tap water analyses raise a red flag, but that more work is needed to replicate the results, find the sources of contamination and evaluate the possible health impacts. She said plastics are very useful, but that management of the waste must be drastically improved: “We need plastics in our lives, but it is us that is doing the damage by discarding them in very careless ways.”