I love a good cup of tea as much as the next person. Rainy afternoon indoors? A cup of tea sounds about right. A suspicious tickle in my throat that suggests a cold might be brewing? Tea, obviously. Mild emotional inconvenience? Tea again. Now imagine my surprise, when I learned that a comforting cup of tea also comes with a dose of microplastics.
Long before plastic ended up in our tea, it made its debut on the pool table. Billiard balls were initially made of ivory from elephant tusks. However, when excessive hunting caused a rapid decline in elephant populations in the 19th century, there was a push to find alternative materials. John Wesley Hyatt went on to create the world鈥檚 first commercially successful plastic, known as celluloid. It was made from cellulose sourced from plant cell walls, including wood. Although the material wasn鈥檛 quite right with how flammable celluloid is, there began the journey to develop plastics as we know them today.
are essentially small particles, comparable in size to a grain of sand, that arise from the breaking down of larger plastics. A large problem with plastics as we鈥檝e come to know them, is that they never really go away. Instead, they just break down into finer and finer particles, carried through soil, water, ice and air into new environments. Just as quickly as they spread through the environment, they become engrained in the food that we eat and the products we use on a day to day basis. Our true consumption of microplastics is still up for debate, as the claim that adults ingest the equivalent of one credit card in microplastics per week has long been . Still, the potential health implications of microplastics, including increased risks of cancer and reproductive problems, are an area of active research.
You may be wondering how microplastics end up in your cup of tea. , a common thermoplastic used in food packaging, is used to seal tea bags shut to help them hold their shape and stay closed while brewing. However, when steeped in hot water, at a temperature of approximately 95掳C or above, PET begins to degrade and lose its integrity, causing small solid fragments of plastic (microplastics) to slough off into the water.
So what prompted this whole 鈥渕icroplastics in our tea鈥� conversation in the first place? One morning, Nathalie Tufenkji, a chemical engineer at 黑料网爆吃瓜, had stopped to order a tea on her walk to the lab and noticed tiny particles swimming in her cup. It was at this point that curiosity kicked in and she, alongside her graduate student, collected an assortment of plastic teabags from various grocery stores and coffee shops. And with that, the began.
They cut the teabags and removed the tea before steeping the empty bag in hot water to mimic brewing conditions. Using electron microscopy, spectroscopy and particle tracking analysis, the particles were quantified and characterized. Still, it left them with questions: were the particles coming from the teabag itself, or were they an artifact of cutting the bag open? Perhaps they came from the tea itself? Various controls were included, such as steeping intact (uncut) teabags and steeping loose tea leaves alone using a metal infuser. The results of the controls told the same story: uncut teabags still shed particles, but loose-leaf tea brewed without the plastic bag did not. It was found that brewing the plastic teabags released approximately 11.6 billion microplastic and 3.1 billion nanoplastic particles into the water, which is far higher than microplastic levels reported in some other foods and drinks. This brings us to an even bigger question: what does this all mean for our own health?
The effects of these released particles were assessed using Daphnia magna, a small aquatic model organism. They exposed the fish to increasing concentrations of the particles for short periods of time, and measured their swimming behaviour. Although survival wasn鈥檛 impacted, the anatomical and behavioral abnormalities in these organisms were clear. With these observations in mind, it鈥檚 hard not to wonder what micro- and nanoplastics might mean for humans. The estimated particle dose from a single teabag is unlikely to cause acute harm, but what repeated, long-term exposure could mean remains an open question.
But can we really avoid microplastics entirely? This is nearly impossible, but before swearing off tea entirely, let鈥檚 talk about why it鈥檚 not all doom and gloom. For one, you can opt for a loose leaf tea and brew it in a stainless steel tea infuser. These reusable infusers help reduce the amount of plastic that ends up both in your tea, and eventually in the environment once a tea bag is thrown out. Can鈥檛 find your favourite herbal tea in a loose leaf form? Fortunately for you, many tea brands are also working towards packaging their tea in biodegradable bags made entirely from natural fiber blends. These small changes to how you brew your tea can make a real difference in reducing your microplastic exposure.
So even if my chamomile has been bringing along a plus-one, it might be time to shut down the party in my cup. Or at least keep the guest list short.
@Harshita Arora
Harshita is a fourth-year (U3) Anatomy and Cell Biology student with a minor in Psychology. In her free time, she volunteers as a first responder, is an avid swimmer, and is always picking up a new hobby 鈥� tennis being her latest pursuit.
