Plastic pollution is becoming a growing concern, and scientists note that its effects are now observed on progressively smaller scales. Recent research in the United States reveals that bottled water harbors hundreds of thousands of minuscule plastic particles previously unaccounted for.

These particles are so tiny that they can penetrate cells and, astonishingly, be transmitted from a mother to her unborn child in the womb.

Nanoplastics can pass "directly into the bloodstream" and get into organs, the Columbia University team said, writing in the journal Proceedings of the National Academy of Sciences in January, where they warned the nanoplastics can "invade individual cells" and "cross through the placenta to the bodies of unborn babies." These so-called nanoplastics are smaller than the microplastics found in rivers and oceans, the byproduct of plastic rubbish being dumped.

An estimated 30 million tonnes of plastic are dumped worldwide each year. In early January, the activist organization Basel Action Network said wealthy countries "cannot manage their plastic waste" as it published data showing European Union exports of plastic trash "to non-OECD countries" as having climbed to 75 million kilograms (165 million pounds) a month in October 2023 from 28 million in May 2022.

Broken-down microplastics, the pieces of which are too small to be seen by the human eye, have for years been known to find their way into the food chain, often through fish. And while it has been known that people ingest even smaller nanoplastics when they drink out of plastic bottles, just how much gets swallowed has not been quantified.

But Columbia's researchers claim to have used "newly refined technology" to access "a whole new plastic world."

"For the first time, they counted and identified these minute particles in bottled water," the university said in a statement, finding that an average liter contains "some 240,000 detectable plastic fragments – 10 to 100 times greater than previous estimates, which were based mainly on larger sizes."