Background
In recent years, increasing attention has been drawn to microplastics—tiny particles resulting from the breakdown of plastics—appearing in nearly every corner of the Earth, including polar ice, soil, drinking water, and food supplies. These particles, ingested by humans and animals, pose potential but largely unknown risks to health and ecosystems. Bottled water has become a major focus of this concern, with studies revealing tens of thousands of detectable fragments in each container.
Advances in technology have now unveiled an even smaller and less understood category of plastics: nanoplastics. These are fragments that originate from the further degradation of microplastics. For the first time, researchers have quantified and identified these microscopic particles in bottled water. On average, they found approximately 240,000 detectable plastic fragments per liter, a figure 10 to 100 times higher than previous estimates based on larger particle sizes.
Nanoplastics are so minuscule that, unlike microplastics, they can penetrate the intestines and lungs, entering the bloodstream and traveling to critical organs such as the brain and heart. They can also infiltrate individual cells and even cross the placenta, potentially affecting unborn babies. Researchers are now working to understand the biological impacts of these particles on human and animal health.
According to Naixin Qian, the study’s lead author and a Columbia University graduate student in chemistry, earlier methods could measure bulk quantities of nanoparticles but struggled to count or identify individual particles. The new study employs a specialized technique called stimulated Raman scattering microscopy, developed by study coauthor Wei Min, a Columbia biophysicist. This technique uses lasers to detect specific molecules, enabling researchers to target seven common types of plastics and identify them accurately.
Bottled Water is safe – or is it?
The team analyzed three popular bottled water brands in the U.S. (kept anonymous), finding between 110,000 and 370,000 plastic fragments per liter. Ninety percent were nanoplastics, while the remainder were microplastics. Among the identified plastics, polyethylene terephthalate (PET)—commonly used in bottle manufacturing—was prevalent, likely introduced into the water through abrasion or heat exposure. Another surprising discovery was the abundance of polyamide (nylon), likely originating from plastic filters used in water purification. Other identified plastics included polystyrene, polyvinyl chloride, and polymethyl methacrylate, all widely used in industrial applications.
Interestingly, the identified plastic types accounted for only 10% of all detected particles, leaving the majority unidentified. This suggests that the true number of nanoplastics in bottled water may be in the tens of millions per liter. The study emphasizes the complexity of these water samples and the challenges in distinguishing nanoplastics from other organic matter.
The research team plans to expand their studies beyond bottled water to investigate tap water, which contains fewer microplastics but is still of concern. They are also examining nanoplastics released into wastewater during laundry, where synthetic fabrics shed millions of particles per load. Other projects include analyzing nanoplastics in Antarctic snow and collaborating with health experts to study their effects on human tissues and neurological development.
“This study sheds light on a previously uncharted area,” said study coauthor Beizhan Yan, an environmental chemist at Columbia’s Lamont-Doherty Earth Observatory. “It provides a window into a hidden world and raises critical questions about the impact of these particles.”
The global production of plastics is nearing 400 million metric tons annually, with over 30 million tons discarded into the environment each year. Products made from synthetic materials also release particles during use. Unlike natural organic matter, plastics do not decompose into harmless substances but instead continue to fragment into smaller particles indefinitely.
Microplastics, ranging in size from 5 millimeters to 1 micrometer, have already been extensively studied. However, nanoplastics—particles smaller than 1 micrometer—represent a new frontier in understanding plastic pollution. Early studies, such as one in 2018, identified an average of 325 microplastic particles per liter of bottled water. Yet, as technology improves, it is becoming clear that the numbers are vastly underestimated, especially when including nanoplastics.
How Do Filters Work Against Nanoplastics?
Water filters are like tiny sieves, catching things we don’t want to drink. Traditional filters, like the ones in many home pitchers, are good at removing bigger impurities like dirt or chlorine. But when it comes to microscopic particles like nanoplastics, more advanced technology is needed.
Here are some of the most effective types of filtration systems available today:
- Reverse Osmosis (RO) Systems
Reverse osmosis is one of the most powerful tools against nanoplastics. It works by pushing water through a special membrane that blocks particles as small as a single nanometer. That’s tiny enough to stop most nanoplastics from passing through. RO systems can remove up to 99% of contaminants, including heavy metals, bacteria, and plastics.Why It’s Great: RO systems are widely available and can be installed under your sink, making clean water accessible for your entire household. - Activated Carbon Filters
Activated carbon filters work by trapping impurities in tiny pores, almost like a sponge. While they’re excellent at removing chemicals and improving taste, they may not catch the smallest nanoplastics unless combined with other filtration methods.Why It’s Great: These filters are affordable, easy to use, and often paired with other technologies to provide extra protection. - Ultrafiltration (UF) Systems
Ultrafiltration uses a membrane similar to reverse osmosis but doesn’t require as much water pressure. These systems are effective at removing microplastics and many nanoplastics, along with bacteria and other contaminants.Why It’s Great: UF systems are energy-efficient and often work well in combination with other filtration systems. - Nanofiltration (NF) Systems
As the name suggests, nanofiltration is designed to handle extremely small particles, including nanoplastics. These systems are specialized and can remove salts, organic matter, and plastics smaller than microplastics.Why It’s Great: Nanofiltration is perfect for those who want the highest level of filtration but don’t need the heavy-duty performance of reverse osmosis. - Multistage Filtration Systems
Some advanced water filters combine multiple methods—like activated carbon, reverse osmosis, and ultrafiltration—to target a wide range of contaminants, including nanoplastics.Why It’s Great: These systems offer the best of all worlds, providing peace of mind that your water is as clean as possible.
What About Everyday Solutions?
While high-tech filtration systems are amazing, not everyone has access to them. Thankfully, there are simple steps you can take to reduce nanoplastics in your water:
- Choose Stainless Steel Bottles: Avoid single-use plastic bottles, which shed particles into water. Instead, refill stainless steel or glass bottles with filtered water.
- Replace Filters Regularly: If you already use a water filter, make sure to change it as recommended to keep it working efficiently.
- Stay Informed: Research the water quality in your area and choose a filtration system that addresses the specific contaminants you’re most concerned about.
A Hopeful Future for Clean Water
The fight against nanoplastics is just beginning, but the progress being made is inspiring. Scientists are discovering better ways to identify and remove these tiny particles, and companies are creating products that make safer water accessible to more people.
Clean water is one of life’s basic needs, and with the right tools, we can ensure it stays that way. Whether you choose a simple filter or an advanced system, every step you take brings you closer to a healthier and safer home. So let’s raise a glass of clean, filtered water and toast to the future—because every sip counts!
