Using lasers, scientists have imaged hundreds of thousands of previously invisible tiny plastic particles in bottled water.

A single bottle of water can contain hundreds of thousands of microscopic plastic particles, potentially posing serious health risks for drinkers, researchers warn. Scientists at Columbia University caution that these nanoplastics, which form as plastics break down into increasingly smaller pieces, can infiltrate vital organs. Consumed daily by people worldwide, their tiny size allows them to penetrate our bodies, reaching the bloodstream and even individual cells.

Nanoplastics can enter our bodies through the lungs or intestines and then travel to various organs, including the heart and brain. Alarmingly, they can also cross the placenta, affecting unborn babies. This concern led a team of researchers to investigate further.

In their study, the scientists analyzed three popular bottled water brands in the United States. They employed advanced lasers to detect plastic particles as small as 100 nanometers – for comparison, a human hair is about 100,000 nanometers wide.

Their findings reveal an average of 240,000 tiny plastic particles per liter of bottled water, a figure 100 times higher than some previous estimates. Of these, 90 percent were nanoplastics, and 10 percent were microplastics. Commonly found nanoplastics included polyethylene terephthalate (PET), a typical substance used in making water bottles, and polyamide, likely originating from the plastic filters used in water purification.

“Previously this was just a dark area, uncharted. Toxicity studies were just guessing what’s in there,” says study co-author Beizhan Yan, an environmental chemist at Columbia University’s Lamont-Doherty Earth Observatory, in a media release. “This opens a window where we can look into a world that was not exposed to us before.”

A tiny particle of polystyrene plastic as imaged by a new microscopic technique. It is about 200 nanometers across, or 200 billionths of a meter.

Other plastics detected were polystyrene, polyvinyl chloride, and polymethyl methacrylate, all used in various industrial processes. Concerningly, these identified plastics comprised only about 10 percent of all the nanoparticles in the samples, leaving the composition of the remaining 90 percent unknown.

Most plastics do not degrade into harmless substances. Instead, they continually break down into smaller particles of the same chemical composition. This ongoing division makes it challenging to determine the exact number of nanoplastics in any given environment.

The Columbia team aims to use their findings to explore the presence of nanoplastics in other areas, such as tap water and wastewater from laundry, which has shown to contain millions of particles per laundry load.

This study emerges as global plastic production, amounting to 400 million metric tons annually, continues to impact the environment. Over 30 million tons of plastic are discarded each year in waterways and on land. As synthetic materials like clothing shed plastic particles during use, experts are still assessing the potential health effects on humans.

“It’s not size that matters. It’s the numbers, because the smaller things are, the more easily they can get inside us,” concludes study co-author Wei Min, a Columbia biophysicist.

The research is published in the journal Proceedings of the National Academy of Sciences.