It is already well-known that single-use coffee cups are an environmental disaster due to the thin plastic lining that makes recycling extremely difficult. However, results from a new study have revealed something more alarming: that hot drink cups release trillions of microscopic plastic particles into the beverage, according to the journal Environmental Science and Technology. Researchers at the National Institute of Standards and Technology analyzed single-use hot beverage cups lined with low-density polyethylene (LDPE), a type of soft, flexible plastic often used as a waterproof lining. It was found that when these cups were exposed to water at 100 degrees Celsius, they released trillions of nanoparticles per liter into the water.
Chemist Christopher Zangmeister, the lead researcher in the study, stated that it is currently unknown whether these plastic particles have harmful health effects on humans or animals, but the microscopic particles are present in the billions in every liter of the drink. He noted that "over the past decade, scientists have found plastics wherever they looked in the environment." Zangmeister also explained that by examining the bottoms of glacial lakes in Antarctica, larger plastic particles (greater than about 100 nanometers) were found, indicating they were likely not small enough to enter cells and cause physical issues. He clarified that the results of the new study are different "because the nanoparticles [found in coffee cups] were so small they could slip inside the cell, potentially leading to disruptions in its function."
A similar study conducted by the Indian Institute of Technology in 2020 found that a hot drink in a single-use cup contained on average 25,000 microplastic particles, along with metals such as zinc, lead, and chromium in the water. U.S. researchers suspect that the findings stem from the same plastic lining. They also analyzed nylon bags used for food packaging, such as bread, which are transparent plastic sheets placed in bread containers to create a non-stick surface that prevents moisture loss. They discovered that the concentration of nanoplastic particles emitted into hot water from food-grade nylon was seven times higher than that from single-use beverage cups. Zangmeister indicated that the results of the study could aid efforts to develop such tests to reduce any negative impacts on human health.
