How does everyday plastic turn into dangerous micro and nanoplastics? Scientists found out

They’re everywhere – in oceans, soil, food, human blood, and even Antarctic snow. Trillions of micro- and nanoplastics, many smaller than a virus, are floating through the environment, too tiny to be seen and nearly impossible to eliminate.

A new study reveals exactly how these plastic shards are formed and why so many end up where they shouldn’t – inside living cells, where they can potentially alter DNA and pose serious risks to human health.

Researchers at Columbia Engineering, led by Sanat Kumar, a professor of chemical engineering, have now uncovered the molecular mechanism behind the formation of these particles.

The findings explain how most common plastics shed nanoscopic pieces into the environment – not just when they’re burned or crushed, but slowly and quietly, just by sitting out in the open.

Understanding nanoplastics – the basics

Nanoplastics are extremely small plastic particles, typically less than 1 micrometer in size.

Unlike microplastics, which are still visible under a microscope, nanoplastics are so tiny they can cross biological barriers – entering cells, tissues, and even the brain in some cases.

Their size and ability to travel within living organisms make them especially concerning from a health and environmental standpoint.

Due to their microscopic size, they are extremely difficult to remove once they enter the environment.

How plastics lose their structure

Most plastics used today – roughly 75% – are made of semicrystalline polymers. These materials have a layered structure that makes them strong, flexible, and long-lasting. Under a microscope, they look like stacks of alternating hard and soft materials.

The hard layers consist of tightly ordered crystals, while the soft ones are more like a jumbled mass. These soft layers act like glue, holding the tougher crystalline sections together.

This delicate balance gives plastic its unique strength – but also its fragility.

Kumar and his team found that the soft layers degrade first, especially when exposed to environmental conditions like heat, light, and moisture.

“What we show in the new study is how easily those soft connectors break even under quiescent conditions such as in a landfill,” he explained.

Once the soft layers give out, the hard crystalline pieces no longer hold anything in place – and they scatter into the environment.

How nanoplastics shed

When these crystalline fragments break loose, they become micro- or nanoplastics. These particles don’t break down easily.

In fact, they can linger in the environment for centuries. Worse, their tiny size allows them to travel through the air, water, and even the human body.

Some of the smallest nanoplastics are small enough to pass through the membranes of human cells.

“These pieces float around, and some end up in human bodies,” Kumar said. “The smallest pieces pass through cells and into the nucleus, where they can start messing with DNA.” 

Because of their shape and persistence, these fragments may behave similarly to asbestos. This disturbing trend is raising concerns about their potential links to cancer, heart disease, and other long-term health problems.

Materials that shed fewer nanoplastics

One solution, Kumar suggests, lies in engineering better plastics. The team’s findings indicate that reinforcing soft layers of semicrystalline polymers makes them more resilient.

Engineers could design materials that shed fewer nanoplastics over time.

“Focus needs to be placed on this point, to reduce the amount of micro- and nanoplastics created by normal polymer degradation,” said Kumar.

Changing the composition of these layers wouldn’t necessarily mean sacrificing plastic’s strength or flexibility, but it could significantly slow down the breakdown process that leads to harmful shedding.

Why does any of this matter?

Today, only about 2% of plastic gets recycled. For many companies, it’s simply cheaper to throw it away. But Kumar argues that this way of thinking doesn’t take into account the hidden health costs of pollution.

“If you just throw plastic into the environment, it creates micro- and nanoplastics that look like they are going to cause health problems,” said Kumar.

Reframing the issue could make a compelling case for additional recycling investments. The medical costs for diseases linked to nanoplastics are staggering.

The financial impact is stark when we consider cancer and cardiovascular issues. “Maybe it’s actually cheaper to recycle,” Kumar argued.

Smarter and safer plastics

This new understanding of how nanoplastics form opens the door to smarter, safer plastic design. Modern research is reinforcing the urgency of this global plastic crisis.

Humans can reduce these harmful particles with innovative waste management solutions and increased recycling.

The Columbia team’s findings serve as a sobering reminder that the plastics we rely on daily – from food packaging to water bottles – don’t disappear when we throw them away.

Plastics quietly degrade into invisible particles, which can travel into our bodies and the broader ecosystem, with consequences we are only beginning to understand.

“If you think about it that way, suddenly the cost of inaction doesn’t seem so low,” Kumar concluded.

The study is published in the journal Nature.

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