Environmental researchers have found that certain bottled water brands contain three times the concentration of nanoplastic particles compared to municipal tap water sources.
COLUMBUS, Ohio — A comprehensive study conducted by environmental scientists at The Ohio State University has revealed that several popular brands of bottled water harbor significantly higher levels of microplastics and nanoplastics than typical municipal tap water. The research, which utilized a novel detection method to identify the smallest of synthetic particles, highlights a growing concern regarding the prevalence of plastic pollution within the global water supply and the potential long-term implications for human health and safety.
The investigation focused on the presence of microplastics and nanoplastics, which are microscopic synthetic particles generated during the manufacturing, use, and degradation of plastic products. These fragments have become a pervasive element of the modern environment, infiltrating remote ecosystems and urban infrastructure alike. To quantify the extent of this contamination in the United States, the research team analyzed water samples collected from four distinct water treatment facilities located near Lake Erie alongside samples from six different commercially available bottled water brands.
According to Megan Jamison Hart, the lead author of the study and a doctoral candidate in environmental sciences at The Ohio State University, the findings were stark. The laboratory analysis demonstrated that bottled water samples contained roughly three times as many nanoplastic particles as the treated drinking water obtained from municipal sources. This disparity suggests that the process of bottling and the packaging materials themselves may be contributing significantly to the plastic load consumed by the public.
The scientific community has long monitored microplastics, but nanoplastics represent a more complex challenge due to their minuscule size. While microplastics are generally defined as particles smaller than five millimeters, nanoplastics are even smaller, often measured in billionths of a meter. Because of these dimensions, they are notoriously difficult to detect using traditional laboratory equipment. To overcome these hurdles, the Ohio State team employed a sophisticated combination of scanning electron microscopy for high-resolution imaging and optical photothermal infrared spectroscopy for precise chemical identification.
This dual-layered approach allowed the researchers to detect and identify particles at a much more granular level than previous studies. By capturing these smaller fragments, the team was able to provide a more accurate assessment of the total plastic content in the samples. The study, which was recently published in the academic journal Science of The Total Environment, suggests that prior research may have significantly underestimated the true scope of plastic contamination by overlooking these nearly invisible nanoplastics.
Hart emphasized that the results empower consumers to make more informed decisions regarding their daily hydration habits. She noted that for individuals looking to reduce their personal exposure to synthetic chemicals and plastic debris, opting for tap water over pre-packaged bottled water is currently the most effective strategy. While tap water is not entirely free of contaminants, the treatment processes utilized by municipal plants appear to be more successful at maintaining lower particle counts than the environments found in bottled water production lines.
The health implications of ingesting nanoplastics remain a subject of intense scientific debate and ongoing investigation. Unlike larger microplastics, nanoplastics are small enough to potentially cross vital biological barriers within the human body, including the intestinal lining and the blood-brain barrier. This mobility raises concerns about the accumulation of plastics in internal organs and the potential for chronic inflammatory responses or the leaching of chemical additives into the bloodstream.
John Lenhart, the senior author of the study and a professor of environmental engineering at Ohio State, indicated that while the full spectrum of human health risks is not yet understood, the evidence of their presence is a call for caution. He suggested that mitigating exposure is a prudent course of action given the increasing data indicating that these particles can cause biological disruptions. The study found that over 50 percent of the particles detected across all samples were categorized as nanoplastics, illustrating how pervasive these chemicals are becoming in the fundamental resources of life.
During the experimental phase, researchers identified that the most common types of plastics found in the bottled water samples were consistent with the materials used in the packaging itself, such as polyethylene terephthalate (PET). This finding confirms suspicions that the friction of opening bottles, the degradation of the plastic under different temperatures, and the bottling process itself are primary sources of contamination. In contrast, the sources of plastics found in municipal drinking water were more varied and less clearly defined, likely reflecting a broader mix of environmental runoff and industrial discharge.
The research team believes that the inclusion of nanoplastics in their measurements marks a significant shift in environmental engineering and public health monitoring. By identifying the specific chemical compositions and concentrations of these particles, engineers can begin to design more effective filtration and remediation systems. Professor Lenhart noted that understanding the basic material composition and the chemical reactions that control these particles is essential for developing the next generation of water treatment technologies.
The implications of this research extend beyond individual consumer choices to the broader field of environmental policy. As the global production of plastic continues to rise, the infrastructure for managing plastic waste and protecting water quality must evolve. The study highlights the need for standardized testing protocols that account for nanoplastics, ensuring that regulatory bodies have an accurate picture of the contaminants present in the public water supply.
Future research stemming from this study will likely investigate which specific municipal treatment processes are most effective at removing nanoplastics. Some modern filtration techniques, such as membrane bioreactors or advanced oxidation processes, may offer higher rates of removal than traditional sand filtration. By pinpointing the most successful methods, the scientific community can provide a roadmap for utilities seeking to upgrade their facilities in response to the growing threat of microplastic pollution.
The study received financial and logistical support from the U.S. National Oceanic and Atmospheric Administration (NOAA) through the Ohio Sea Grant College Program, as well as the National Science Foundation. These partnerships underscore the importance of interdisciplinary research in addressing complex environmental challenges that intersect with public health and engineering. As more data becomes available, the focus will likely shift toward finding a balance between the convenience of modern packaging and the necessity of maintaining a clean, plastic-free water supply.
Ultimately, the Ohio State study serves as a reminder of the unintended consequences of plastic ubiquity. While bottled water is often marketed as a purer alternative to the tap, the scientific reality suggests a more complicated narrative. For the average consumer, the message is one of moderation and awareness. By prioritizing tap water and reusable containers made of non-plastic materials, individuals can play a small but significant role in reducing the demand for single-use plastics and lowering their own intake of nanoplastic particles.
