Do Disposable Coffee Cups Release Hundreds of Millions of Plastic Particles When Exposed to Hot Water?

The Hidden Danger in Your Daily Coffee: Microplastics

Coffee is the drink working professionals reach for to get through the day. And as everyone knows, brewed coffee is a liquid, which means it needs a container. But how many of us actually remember to bring our own cup every single day? More often than not, we end up with the disposable cup the café hands us. American researchers have now found that when to-go coffee cups and similar plastic products sit in hot water for just 20 minutes, they release trillions of plastic particles.

Our dependence on coffee has made one cup a day the standard routine. Five working days a week means steadily ingesting a meaningful amount of plastic. And this isn't hypothetical—back in 2018, Austrian scholars warned that human bodies had already been contaminated with microplastics. In 2019, researchers in Austria confirmed that every 10 grams of stool samples contained 20 microplastic particles.

More recent studies have shown that these microplastics turn up not only in human blood but in lung tissue as well. Plastic, clearly, has become one of the invisible threats to human health.

Understanding Microplastics vs. Nanoplastics

It's worth noting that "microplastics" carry two definitions depending on particle size. What most people call microplastics are plastic particles smaller than 5 millimeters—small, but still visible to the naked eye. Smaller still are "nanoplastics," below one-millionth of a meter (1 micron), which generally can't be seen even under a standard microscope.

Research Findings on Plastic Leaching

Researchers at the National Institute of Standards and Technology (NIST) studied two plastic products in everyday use: the LDPE plastic film lining commonly found inside disposable hot beverage cups, and the oil-resistant food-grade nylon used in baking liners.

What they found: when these plastics meet hot water, they release trillions of particles per liter. The concentration of nanoparticles released into hot water from the food-grade nylon was seven times higher than from the LDPE lining.

Using scanning electron microscopy (SEM), the researchers observed that the particles averaged between 30 and 80 nanometers, with only a handful exceeding 200 nanometers.

The Invisible Threat in Your Hot Drinks

When you're strolling down the street happily sipping a hot coffee, tea, or milk drink, you're thinking about how good it tastes—not that even in an establishment with spotless food hygiene, your hot beverage still carries billions of invisible microplastic particles. Knowing that, doesn't the drink in your hand suddenly seem a little less appetizing?

Because nano-sized plastics can enter biological cells and interfere with their normal function, the health implications are serious. The U.S. Food and Drug Administration (FDA) regulates the plastics used in food packaging—food-grade nylon (common in tea bags) among them—and specifies that they should not lose more than 1% of their mass under high-temperature conditions. Yet the new analytical technique used in the NIST study revealed mass losses of up to 10%, far beyond the FDA's safety threshold.

What's more, the corresponding author of the NIST study pointed out that there is no commonly used test for measuring how quickly LDPE dissolves from hot beverage cups—tests exist only for nylon plastics.

A Simple Solution: Bring Your Own Cup

So can we still enjoy a hot coffee without worrying? Absolutely—just bring your own reusable cup when you head out and the problem is neatly solved. It saves resources, too, and spares you any doubts about how well the shop's cups were cleaned.

Image source: Internet

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FrontStreet Coffee Recommendation

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