But are they harmful?
Scientists are rushing to study the tiny plastic specks that are in marine animals — and in us
Dunzhu Li used to microwave his lunch each day in a plastic container. But Li, an environmental engineer, stopped when he and his colleagues made a disturbing discovery: plastic food containers shed huge numbers of tiny specks — called microplastics — into hot water. “We were shocked,” Li says. Kettles and baby bottles also shed microplastics, Li and other researchers, at Trinity College Dublin, reported last October1. If parents prepare baby formula by shaking it up in hot water inside a plastic bottle, their infant might end up swallowing more than one million microplastic particles each day, the team calculated.
What Li and other researchers don’t yet know is whether this is dangerous. Everyone eats and inhales sand and dust, and it’s not clear if an extra diet of plastic specks will harm us. “Most of what you ingest is going to pass straight through your gut and out the other end,” says Tamara Galloway, an ecotoxicologist at the University of Exeter, UK. “I think it is fair to say the potential risk might be high,” says Li, choosing his words carefully.
Researchers have been worried about the potential harms of microplastics for almost 20 years — although most studies have focused on the risks to marine life. Richard Thompson, a marine ecologist at the University of Plymouth, UK, coined the term in 2004 to describe plastic particles smaller than 5 millimetres across, after his team found them on British beaches. Scientists have since seen microplastics everywhere they have looked: in deep oceans; in Arctic snow and Antarctic ice; in shellfish, table salt, drinking water and beer; and drifting in the air or falling with rain over mountains and cities. These tiny pieces could take decades or more to degrade fully. “It’s almost certain that there is a level of exposure in just about all species,” says Galloway.
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