A different small study in the Republic of Ireland published in June also found microplastic contamination in a few 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 stated there were two principal concerns: the chemicals or pathogens which microplastics can harbour as well as very small plastic particles. “If the fibres are there, it is possible that the nanoparticles are there too that we can’t measure,” she said. “Once they are in the nanometre range they can really penetrate a cell and that means they can penetrate organs, and that would be worrying.” The Orb investigations caught particles of more than 2.5 microns in size, 2,500 times larger than a nanometre.
Microplastics can bring bacteria found in sewage, Mahon said: “Some studies have shown there are more harmful pathogens on microplastics downstream of wastewater treatment plants.”
Microplastics are known to contain and absorb toxic compounds and research on 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.” His research has shown microplastics are found in a third of fish caught in the UK.
The scale of international microplastic contamination is only starting to become clear, with studies in Germany finding fragments and fibers in all of the 24 beer manufacturers they analyzed, as well as in sugar and honey. In Paris in 2015, researchers discovered microplastic falling out of the air, which they estimated deposits three to 10 tonnes of fibres on the city annually, and that it had been also present in the air in people’s homes.
This research led Frank Kelly, professor of environmental health at King’s College London, to tell a UK parliamentary inquiry in 2016: “If we breathe them in they could potentially deliver chemicals to the lower parts of our lungs and maybe even across into our circulation.” Having seen the Orb data, Kelly told the Guardian that research is urgently needed to ascertain whether eating plastic particles is a health risk.
The new research tested 159 samples using a standard technique to remove contamination from other sources and was performed at the University of Minnesota School of Public Health. The samples came from across the world, including from Uganda, Ecuador and Indonesia.
How microplastics end up in drinking water is for now a mystery, but the atmosphere is one obvious source, with fibers drop by the wear and tear of clothes and carpets. Tumble dryers are another potential source, with almost 80% of US households having dryers that port to the open air.
“We really think that the lakes [and other water bodies] can be contaminated by cumulative atmospheric inputs,” said Johnny Gasperi, at the University Paris-Est Creteil, who did the Paris studies. “What we observed in Paris tends to demonstrate that a huge amount of fibres are present in atmospheric fallout.”
Vinyl fibers may also be flushed into water systems, using a recent research finding that each cycle of a washing machine could release 700,000 fibres into the environment. Rains could also sweep up microplastic pollution, which might explain the family wells utilized in Indonesia were found to be contaminated.
In Beirut, Lebanon, the water supply comes from natural springs but 94 percent of the samples were contaminated. “This research only scratches the surface, but it seems to be a very itchy one,” said Hussam Hawwa, at the environmental consultancy Difaf, which collected samples for Orb.