These findings, part of a new study by the Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, mark the first time nanoplastics have been measured this precisely in the open ocean, and the results are staggering.
Unlike microplastics, which have become an environmental shorthand for ocean pollution, nanoplastics are even smaller, able to slip past most filters, pass through biological membranes, and potentially accumulate in tissues, including those of humans.
According to the researchers, these near-invisible particles are far more numerous than the micro- and macroplastics floating in the same waters, making them a much bigger concern than previously thought.
How they measured the invisible
The research team collected seawater during a voyage aboard the RV Pelagia, using ultra-fine filters to capture particles below one micrometre in size. By analysing their chemical signatures with high-end mass spectrometry, the scientists could quantify just how much nanoplastic was present, and identify what kind of plastic it was.
This study is the first to provide an accurate estimate of nanoplastic concentration in the marine environment, and the numbers far exceed earlier assumptions. The sheer volume, 27 million tons, suggests that most ocean plastic pollution might exist in forms we’ve never even seen.
Where they come from, and where they end up
These particles don’t just drift in from obvious trash. While some originate from the breakdown of larger plastic waste exposed to sun and waves, others arrive by river runoff or even fall from the sky, carried by atmospheric currents and deposited through rain.Once in the ocean, nanoplastics spread through every layer of the marine food web, from bacteria and plankton up to fish, seabirds, and marine mammals. The concern, scientists say, is not just ingestion but penetration: nanoplastics can lodge deep in tissue, including brain and organ cells. That puts both marine species and humans, who eat seafood, at potential risk.
Cleanup isn’t an option. Prevention is.
Given their microscopic size and enormous distribution, removing nanoplastics from the ocean is impossible with current technology. That’s why researchers stress prevention: stopping plastic from entering the oceans in the first place is the only realistic way to curb the spread.
Ongoing work is now focused on understanding how different types of nanoplastics affect living organisms and whether similar pollution levels exist in other oceans. But one thing is clear, this isn’t just about marine life anymore. With the ability to cross the blood–brain barrier, nanoplastics could be a direct threat to human health.
The study serves as a stark warning: what we throw away doesn’t just float, it breaks down and spreads, often far beyond what we can see, touch, or clean up. And it’s already here.
With inputs from TOI
