New research from Ohio State shows some bottled water brands contain three times as many nanoplastic particles as treated tap water. The findings highlight how everyday choices, like reaching for the tap instead of a bottle, can cut exposure to tiny plastic fragments.
Reaching for a bottle of water instead of the tap might feel like the safer choice. New research suggests it often is not.
Scientists at The Ohio State University found that some brands of bottled water contained roughly three times as many nanoplastic particles as treated tap water from nearby municipal plants, raising fresh concerns about how much plastic people may be drinking every day.
The team focused on water from four treatment plants near Lake Erie and six different brands of bottled water. By comparing the two sources, they were able to estimate how many microscopic plastic fragments were present in each.
Their analysis showed that bottled water carried significantly higher levels of nanoplastics, the tiniest category of plastic particles. These fragments are so small that they are measured in billionths of a meter and can be difficult to detect with standard tools.
The findings point to a simple way for people to cut down on exposure, according to lead author Megan Jamison Hart, a doctoral candidate in environmental sciences at Ohio State.
“We can make educated choices to try and reduce our daily exposure to these harmful chemicals,” Hart said in a news release. “For the average person who is thirsty and wants a drink, the best way to do that would be drinking it straight out of the tap rather than grabbing pre-bottled water.”
Microplastics and nanoplastics form as larger plastic products break down or are used over time. They have been detected in oceans, rivers, soil and even the air. Because plastics are so durable and widely used, these tiny fragments are now considered a global pollutant.
Scientists have been measuring microplastics in drinking water for several years, but far fewer studies have focused on nanoplastics. Their extremely small size makes them harder to spot and track, even in a laboratory.
To overcome that challenge, the Ohio State team combined two advanced techniques. They used scanning electron microscopy to image the particles and optical photothermal infrared spectroscopy to identify their chemical makeup. Together, these tools allowed the researchers to detect and classify plastic particles down to their smallest components.
The study, published in the journal Science of The Total Environment, found that more than half of all particles detected in the water samples were nanoplastics. That result suggests that earlier work that only counted larger microplastics may have underestimated how much plastic is actually present in drinking water.
Although scientists are still working to understand exactly how these particles affect human health, many worry that nanoplastics pose a particular risk. Because they are so small, they are more likely to cross important biological barriers in the body, potentially reaching organs and tissues that larger particles cannot.
That uncertainty is precisely why it makes sense to limit exposure where possible.
“While we don’t really fully understand the human health risks associated with nanoplastic exposure, it’s still better to try and mitigate that risk because evidence indicates that they do cause problems, even if we’re not fully aware of what those are yet,” Hart added.
In the bottled water samples, the most common plastics could be traced back to the packaging itself, which the researchers expected. Plastic bottles and caps can shed tiny fragments during manufacturing, shipping, storage and everyday handling.
The source of plastics in the treated tap water was less clear. The particles could be entering the system from natural waterways, aging infrastructure or other parts of the treatment and distribution process. Pinpointing those pathways will require more study.
What is clear is that nanoplastics are a major part of the plastic pollution picture and need to be included in future monitoring and risk assessments.
Counting these smaller particles changed the overall picture of contamination, noted senior author John Lenhart, a professor of environmental engineering at Ohio State.
“The concentrations we saw were higher than anticipated, which, unlike prior studies, we were able to attribute to the inclusion of the nanoplastics,” he said in the news release. “That emphasis validates a lot of the information we’ve learned.”
By folding nanoplastics into their measurements, the team hopes to open the door to new questions: Which water treatment methods are best at removing these particles? How do different materials and processes contribute to plastic shedding? And how can engineers design systems that keep more plastics out of drinking water in the first place?
“By understanding the basic composition of the materials in water and the reactions important for controlling that composition, we can make better design decisions for future treatment or for remediation,” Lenhart added. “That’s why analyses like these are so promising.”
For now, the researchers stress that people do not need to panic about every sip of water. Instead, they emphasize practical steps: choosing tap water when it is safely treated, using reusable bottles made from materials that shed fewer particles, and supporting efforts to reduce plastic waste overall.
As scientists continue to refine tools for spotting ever-smaller pieces of plastic, studies like this one suggest that what we cannot easily see in our water may still matter — and that everyday choices can help limit what ends up in our bodies.
Source: The Ohio State University