Plastics are supposed to be chemically inert. It’s the reason they’re used so frequently to package food, bottle water, and create children’s toys: They’re safe.
But something important happens when a large piece of plastic fragments into micro- and nanoparticles. Its surface area increases dramatically relative to its volume. Vastly more of the material is now exposed to its surroundings.
A new study by researchers from Columbia University and the University of California, Berkeley, found that this newly created surface is not necessarily safe, and identified the chemical reasons why.
“As plastic fragments into smaller and smaller particles, its surface area increases enormously. Then microplastics change the water that surrounds them, generating high-energy, reactive radicals (reactive oxygen species, ROS) that very likely contribute to biological damage that we see in animals and potentially in humans as a result of microplastic exposure,”
This is particularly noteworthy for human health because human blood is largely made up of water. The new research suggests that microplastics that enter the bloodstream or cells could remain chemically active in this water-rich biological environment.
Min’s group at Columbia University also led a 2024 study that developed a laser based microscope technology and found that on average, a liter of bottled water contained some 240,000 detectable plastic fragments (mostly nanometer-sized plastic, nanoplastics)—10 to 100 times more fragments than had previously been estimated. That study led to a growing recognition that micro and nanoplastics exist throughout the food system.
