Many people choose bottled water believing it is cleaner and safer than tap water. But new research suggests that this assumption may not always be true.
A recent study has found that some bottled water contains far more tiny plastic particles than treated tap water, raising fresh questions about everyday exposure to plastic pollution.
Microplastics and nanoplastics are extremely small pieces of plastic that form as larger plastic items break down over time.
They are now found almost everywhere in the environment, from oceans and rivers to soil, air, and even drinking water.
Because plastic production continues to grow worldwide, these particles are steadily building up around us.
To better understand how much plastic ends up in drinking water, researchers studied water samples from four drinking water treatment plants near Lake Erie, along with six popular brands of bottled water sold in the United States.
The study was led by Megan Jamison Hart, a PhD researcher in environmental sciences at Ohio State University.
The results were striking. Bottled water contained about three times as many nanoplastics as the treated tap water.
Nanoplastics are even smaller than microplastics and are so tiny that they are invisible to the naked eye. Hart said that for most people simply looking for a drink of water, choosing tap water may be a better way to reduce daily exposure to these particles than relying on bottled water.
One reason this issue has gone largely unnoticed is that nanoplastics are extremely difficult to measure. Previous studies mainly focused on larger microplastics because they are easier to detect.
In this research, scientists used advanced imaging and chemical identification tools that allowed them to see and identify plastic particles at a much smaller scale than before. This new approach revealed that more than half of all plastic particles found in the water samples were nanoplastics.
The study was published in the journal Science of the Total Environment and adds to growing concerns about how these tiny plastics may affect human health.
While scientists do not yet fully understand the health risks, many experts worry that nanoplastics may be more harmful than larger plastic pieces. Their small size means they may be able to cross biological barriers in the body and reach sensitive organs.
The researchers also looked at where the plastics might be coming from. In bottled water, many of the plastic particles appeared to come directly from the packaging itself. This was expected, as plastic bottles and caps can shed particles over time. The source of plastics found in tap water, however, remains less clear.
Senior author Professor John Lenhart said the findings suggest that plastic contamination in water may be far more widespread than previously believed, largely because nanoplastics have been overlooked. He hopes the new methods used in this study can help scientists understand which water treatment processes are most effective at removing these tiny particles.
As research continues, the findings highlight a simple but surprising message: bottled water is not always the cleaner option, and in some cases, turning on the tap may actually expose you to fewer plastics.
