Disposable coffee cups are already considered an environmental scourge because their thin plastic lining makes them difficult to recycle. Now a new study suggests that hot drink containers release trillions of microplastic particles into your drink.
Researchers at the National Institute of Standards and Technology analyzed single-use hot drink cups coated with low-density polyethylene (LDPE), a soft and elastic plastic film commonly used as a waterproof lining.
They found that when the cups were exposed to water at 100 C(212 F), they released trillions of nanoparticles per liter of water.
"The main conclusion is that there are plastic particles everywhere we look, and lots of them," said NIST chemist Christopher Zammeister. We don't know if there are adverse health effects in people or animals, but we can confirm their presence."
To analyze the nanoparticles released from the coffee cup, Zammeister and his team isolated the nanoparticles from the rest of the solution by spraying the cup with a fine mist of water and then allowing it to dry.
The technique has been used before to detect tiny particles in the atmosphere. After the spray dries, the nanoparticles in it are sorted by size and charge. The researchers can then specify a specific size, say about 100 nanometers of particles, and put them into a particle counter.
The nanoparticles are exposed to hot vapors of butanol and then rapidly cooled. As butanol concentrates, the particles expand from nanometers to microns, making them easier to detect.
The process is automated, with computer programs running to count the number of particles.
Currently, there is no commonly used test to measure LDPE released into water from samples such as coffee cups, and the findings from this study could help develop such tests, Zammeister noted. At the same time, he and his team analyzed water in other consumer goods and materials, such as fabrics, cotton-polyester, plastic bags, and plastic pipes.
The findings of this study, combined with other types of material analysis, will open new avenues of research and move this field forward.
