Billions of microplastics in your tea bag

HostI was at the store the other day looking at those fancy tea bags. They look like little silk pyramids and they feel much nicer than the old flat paper ones. But I heard something that made me put them back on the shelf. Why is a single tea bag leaking billions of tiny plastic bits into a cup?

GuestIt's a shock when you hear the numbers. We have all seen those mesh bags. They look nice, and the companies often call them silken. But they're not silk. They're almost always made of nylon or a type of plastic that's also used to make soda bottles. When a group of scientists in Montreal decided to look at what happens when you steep these bags, they were stunned. They found that just one bag, when it sits in hot water, lets out about eleven billion tiny bits of plastic. And those are just the ones they could see. There were trillions of even smaller specks, too small for a normal microscope to even find.

HostEleven billion? That sounds like a made-up number. If that much plastic is coming off the bag, wouldn't the bag just fall apart?

GuestYou would think so, but it shows just how small these bits are. If you took all eleven billion bits and piled them up, they would still be way smaller than a grain of sand. The bag stays together because the main shape is still there, but the surface is basically shedding. Think of it like a snake losing its skin, but on a level that's too small for us to see. The plastic isn't melting into a puddle. But when you pour boiling water over it, the heat gives the plastic chains enough energy to start wiggling and breaking loose. Those tiny bits just float off into your tea, and because they're so light, they stay in the water while you drink it.

HostBut we have used paper tea bags for a long time and they seem to stay together just fine. Why did anyone feel the need to switch to plastic if it does this?

GuestIt mostly comes down to how the bags look and how they're made. Paper is great, but it's hard to make those pyramid shapes out of it. Those shapes are popular because they give the tea leaves more room to move around and grow, which is supposed to make the tea taste better. Also, plastic bags can be heat-sealed. Instead of using glue or a metal staple to keep the bag shut, the factory just hits the edges with a bit of heat and the plastic melts together. It's cheap and fast for the machines. But that same trait, that way they melt and bond with heat, is why the bag starts to break down the moment it hits your hot mug.

HostSo it's the heat that's the real problem. If I were making iced tea and just let the bag sit in cold water, would it be fine?

GuestIt would be better, but it's still not great. Plastic is more steady when it's cold, sure. But even in cool water, some of those tiny bits are going to flake off. The hot water just speeds everything up. It acts like a hammer, hitting those plastic bonds over and over until they snap. The real catch is that tea is almost always made with water that's just below boiling. That's the exact place where these plastics start to fail. We're taking a material that reacts to heat and putting it in the hottest thing we have in our kitchen.

HostIt feels like there should be some kind of rule against this. If there are billions of plastic specks in a drink, wouldn't the government step in?

GuestThe laws we have for food bags are a bit behind the times. Most of our rules were written back when we thought plastic was totally solid and didn't move. As long as the plastic itself isn't made of something known to be a poison, it gets a pass. But those rules don't look at the physical bits themselves. They look at the stuff that makes up the plastic. We're only just now starting to learn what happens when we swallow billions of tiny solid specks. Some studies show these bits can get into our gut or even our blood. We don't have a clear answer on the long-term harm yet, but it's certainly not what people think they're getting when they brew a cup of tea.

HostIt's strange because we spend so much time trying to cut down on plastic straws, but here we're soaking plastic in our drinks.

GuestIt's a big gap in how we think about what's clean. We see a shiny, clear bag and think it looks pure. But the old, brown paper bag is actually much cleaner for our bodies. Even the bags that claim to be made from plants can be tricky. Some of them are made of a plastic made from corn, but they still let out these tiny bits in the same way. The only way to really be sure is to go back to the basics. Using loose tea in a metal strainer or sticking to plain paper bags means you're not drinking a soup of plastic bits along with your tea.

HostThe most startling part is that a single cup of this tea might have more plastic bits than you would find in all the bottled water you drink in a whole year.

GuestScientists found that the sheer number of bits in one cup was thousands of times higher than what we see in any other foods or drinks we consume.

HostThat fancy pyramid bag doesn't look quite so high-end when you realize it's just shedding into the water.