After all, microplastics are not inert: in water, they produce DNA-damaging free radicals: ScienceAlert

As social media says, microplastics are leading this generation, just like asbestos: useful things that seemed great – until they weren’t.

Plastics are ubiquitous because they are durable, versatile and seemingly stable.

As a result, they literally occupy our hearts and every environment, from deep seas to ancient rocks. They’ve even created their own ecosystem of plastic-eating plants and animals, filled with invasive species.

Health problems are piling up as fast as plastics, and new evidence suggests that these materials are not inert after all.

It’s a worrying revelation for people who prefer not to harbor synthetic shrapnel in their reproductive organs: Researchers at Columbia University and the University of California, Berkeley, have demonstrated that microplastics become chemically active in water, catalyzing the creation of DNA-damaging free radicals.

This revelation, which has just appeared in the journal Natureis of great importance given that our world is covered in water.

And guess what our body is mainly made of.

“Our research found that when microplastics interact with water, such as when they are in bottled water or when they are absorbed into our bloodstream, they spontaneously generate (these) high-energy reactive radicals,” says first author Naixin Qian, a biotechnology chemist at Columbia University.

The researchers used several laboratory experiments, analytical techniques and calculations to explore the reactivity of microplastics in water.

Their small size modifies their properties:

“As plastic fragments into smaller and smaller particles, its surface area increases enormously,” says Wei Min, co-author of the study and leader of the Min group focused on biomolecular dynamics at Columbia University.

“Then, microplastics modify the water around them, generating high-energy reactive radicals that most likely contribute to the biological damage we see in animals and potentially in humans following exposure to microplastics.”

The researchers included six common laboratory-grade powdered commercial plastics and searched three lines of chemical evidence to demonstrate the formation of free radicals, particularly those of the hydroxyl type.

Comprised of oxygen and hydrogen, hydroxyl (OH) free radicals are among the most reactive and toxic types, whose cell-killing prowess helped found the burgeoning—and perhaps not so effective—antioxidant industry.

Based on observations, free radicals appear to originate from the interface of microplastics and water.

Then, when researchers introduced lysozyme, a protein found in human bodily fluids like tears, saliva, mucus and milk, they saw it clump together in a perhaps not-so-healthy way; Moreover, clumps of proteins in the brain are the cause of neurodegenerative diseases.

The addition of caffeine acted as a molecular shield, stopping this effect because caffeine is an antioxidant. But its protective effects are different in the laboratory and in the body.

The researchers also tested mouse-derived red blood cells, which were distorted and fragmented by the process of free radical production.

Overall, the reactivity of microplastics is due to a counterintuitive cause.

The most hydrophobic (water-repellent) microplastics are the most reactive, and it is precisely for this reason. By repelling water, they affect its molecular structure.

This reorganization of water molecules leads to changes in electrostatic forces, which also affect cats and packing peanuts.

In short, dissolved oxygen or hydrogen ions near the hydrophobic plastic surface capture electrons from hydroxide ions in the water, transforming them into hydroxyl free radicals.

The researchers also mention the large number of processes that transform bulk plastics into microplastics.

In addition to industrial processes like (huge surprise) plastic manufacturing, our daily habits flood our fleshy bodies and homes with microplastics.

Even opening and closing a water bottle abrades its cap.

Even opening and closing a water bottle abrades its cap.

“Various uses and processes in our daily lives can also generate microplastics, including microwave heating, exposure to sunlight of bottled water during storage, and intravenous injections in health care settings,” says Beizhan Yan, study co-author and environmental geochemist at the Columbia Climate School.

“This foundational work offers a potential avenue for understanding their health impacts.”

Yan and other researchers, including co-authors of this work, are now using animal studies to determine how plastic particles migrate into fetal tissues during gestation.

Researchers are also exploring solutions worth the cure by testing how to reduce our exposure to tiny plastics.

Overall, the situation has sparked federal action: Earlier this year, the U.S. Department of Health and Human Services (HHS) launched the $144 million STOMP program to eliminate human-impregnated microplastics.

A potential future solution? Change our plastics, or at least their surfaces, because this work suggests that electrical, physical and chemical activity occurs here.

As Teresa Head-Gordon, a theoretical chemist and director of her eponymous Berkeley laboratory, concludes, this “could ultimately lead to new technical solutions by rethinking the chemistry of these basic plastics to reduce toxic effects on health and the environment.”

The research was published in Nature.