How this versatile material is impacting human and environmental health.

Blog Post by Brittnee Stivey

Plastic has become an integral part of our everyday lives. It’s cheap, versatile and incredibly durable, and as a result, it has taken on many forms, from food packaging, to electronics, to water bottles and even car parts! However, it is no secret that due to the nature of its durability, plastic does not break down or degrade. Instead, it breaks apart and fragments into increasingly smaller pieces until eventually, it becomes microplastic. Recent studies have also discovered that some plastics leach chemicals over time, which can end up in food and drink and are then consumed by us, for example in drinks packed in plastic bottles. It is becoming apparent that this versatile material that we rely upon is posing significant risks to the environment and human health.

Tiny fragments and filaments of plastic in table salt crystals.
*Photo: Paulo Oliveira/Alamy*

The investigation and understanding of the impact and presence of microplastics and nanoplastics in the environment is an emerging field of discovery and concern. A microplastic is defined as a particle of plastic that is under 5 millimetres in size, while any particle smaller than 1 micrometre in size is defined as a nanoplastic (Hartmann et al., 2019). Plastic particles have been found in some of the most remote places around the world, such as the bottom of the Mariana Trench, and in 2022, nanoplastics were discovered in a living person’s blood for the first time (Leslie et al., 2022). Tiny fragments of plastics have been found in many things that we consume, including beer, soft drinks, rice, fruits, vegetables, tap and bottled water, honey, fish, salt, and milk (De-la-Torre, 2020; Oliveri Conti et al., 2020). It is clear that the presence of micro- and nanoplastics is an issue greater in scope than initially understood, and is a threat impacting our lives in ways never previously identified. It is then no surprise that micro and nanoplastics are being identified more and more in foodstuffs and products we consume every day.

We can explore chewing gum as an example. It might come as a shock to discover that the base ingredient in many chewing gum brands is polyvinyl acetate - a type of plastic that is also used in the production of glue, plastic bags and bottles. The addition of polyvinyl acetate into chewing gum is a fairly recent development - up until the 1960s, chicle (a type of tree sap) was used as the base in most chewing gums. Eventually, chicle was swapped out for synthesised materials including polyethylene and polyvinyl acetate to cut down manufacturing costs. Most people aren’t even aware that plastic is used in chewing gum, as it is usually listed as ‘gum base’ in the ingredients section of gum packets, including many popular Australian brands such as Wrigley’s, P.K., and 5 Gum.

Thankfully, plastic-free gums are slowly making a comeback, and they’re already on the market in Australia. Melbourne-based Honest Gum is one such product. It uses a chicle base instead of polyvinyl acetate and comes in a variety of flavours, and is made without any other synthetic ingredients. It is worth noting that the packaging, and the gum itself, are 100% compostable too! Another plastic-free alternative that is made in Australia is Mast Chew. This product uses an organic gum base known as mastic - a type of tree resin found in the Pistacia plant. It also contains all-natural ingredients, plus it’s digestible, so no need to worry if you accidentally swallow your gum! The resurgence of plant-based chewing gum is taking shape all over the globe - it is a small, chewy step that gum lovers everywhere can take towards reducing the amount of plastic that ends up in the environment, and in our bodies!

Another, perhaps surprising, example of inadvertent nonplastic consumption is tea bags. Around 96% of tea bags contain a plastic called polypropylene terephthalate (PET), a plastic resin widely used for packaging foods and beverages. It is used to seal a tea bag shut and help keep its shape, such is the case with brands like Bushell’s, Tetley and Nerada. In 2019, Professor Nathalie Tufenkji and her team at McGill University discovered that steeping a plastic tea bag at 95 degrees Celsius released around 11 billion microplastic particles, and 3 billion nanoplastic particles into a single cup of tea (Hernandez et al., 2019). That’s a mind-boggling amount of plastic to be ingesting with your afternoon cuppa! A simple solution to avoid this would be to switch to drinking tea that comes in plastic-free bags made from unbleached paper or plant fibres, and are stitched or stapled together rather than glued or heat-sealed shut, such as Lipton’s Quality Black and Intense products, Pukka bagged tea and Nature’s Cuppa Organic. As of February 2021, Twinings have also rolled out plastic-free tea bags on all string and tag tea bags. Alternatively, using loose-leaf tea, metal and silicone-based tea infuser, like our super cute ManaTea, completely bypasses the need for tea bags - and you get a stronger, richer-tasting cup of tea too!

It seems that, whether we wanted them to or not, microplastics and nanoplastics have infiltrated every corner of our lives. From chewing gum to teabags, to plastic bottles, seafood and even in the air itself, human exposure to microplastics has become unavoidable. It is estimated that the average person ingests about a credit card’s worth of plastic every week (WWF, 2019), or around 50,000 microplastic particles a year, however, there are still large gaps in knowledge as to what sort of effect this has on our health and bodily functions.

Another potential risk to human health is the chemicals some plastics release over time. One such plastic is PET, the same plastic used in tea bags for sealing and keeping their shape. This is commonly what plastic drink bottles are made of. PET is known to contain chemicals known as food contact chemicals, which are safe in low concentrations.

However, one European study found that 150 chemicals present in PET plastic drink bottles were leaching into the beverages contained inside them, and 18 of those exceeded health regulation levels (Gerassimidou et al., 2022). Some of these substances have the potential to cause serious health effects, one in particular being antimony, a semi-metal that is added to plastic bottles as antimony trioxide to increase the rate of chemical reaction that creates the PET resin. Antimony is toxic and prolonged exposure to it can cause lung disease, heart problems, and gastrointestinal issues to name a few. Antimony leaches into the drink contained within the bottle faster if it is exposed to high temperatures during storage and transport. Other chemicals, such as phthalates, passively leach into drinks and don’t need to be exposed to heat or long periods of time in order to accumulate within the drink inside the bottle.

Interestingly, a study conducted in the UK discovered that the risk of contamination increases if the bottle is made from recycled PET as opposed to virgin PET. This is because the chemicals that end up in PET plastic bottles may be non-intentionally added substances (NIAS), and the presence of these in the bottles plus any contaminants that are added during the recycling process can accumulate in potentially dangerous quantities in the recycled PET material.

It is clear that there needs to be more regulation of chemical contamination at every stage of the creation and recycling of PET bottles to narrow down the source of NIAS and keep them out of the entire process. This is an essential step that needs to be introduced, especially as large-scale companies are pledging to reduce their carbon footprint by creating recycled and recyclable packaging. The Australian branch of Coca-Cola, has committed to making all their packaging 100% recyclable by 2025, and using at least 50% recycled materials in their bottles by 2030.

It is important to note that many of these studies have been conducted in places like the UK, Europe and America. There seems to be minimal literature available on Australia-centric studies and therefore there is little statistics available on what the PET plastic bottle industry is like in Australia. However, plastic pollution is a global issue and awareness of the problem is key to driving consumer change.

The good news is, there are scientists and innovators all over the world working on projects right now with the aim of removing micro and nanoplastic particles from the environment and things we consume. Alongside this, there are also simple strategies we can each undertake in our daily lives to minimise our exposure to plastics, and reduce the potential for contamination. Simple consumer choices, opting to use plastic-free alternatives, and disposing of our waste correctly can all make a huge difference. If you are looking to switch to reusable options, consider checking out the MMF Shop and browsing our range of sustainable items, including our re-usable shopping bags, eco-bottles, and rice husk travel mugs. A shift away from reliance on plastics for food and drink packaging will help to pave the way towards a circular economy of proper recycling, and in turn, reduce the amount of plastic waste that ends up in our bodies and in the oceans. The goal is a plastic-free future, but it is going to be a global effort to get there.

Check out our other blogs for more information about how plastics affect our local environments, and ways we can make a difference!

National Recycling Week: Microplastics

Beyond Plastic Free July

Ocean Plastic: Keep it Clean!

Busting Recycling Myths

Plastic Free July with the Marine Mammal Foundation

The Marine Mammal Foundation is a not-for-profit charity organisation, protecting the marine environment through research, community engagement and education. Please consider supporting us with a tax-deductible donation.

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Bioengineering a Future Free of Marine Plastic Waste

Microplastics found in human blood for first time | Plastics | The Guardian

Magnets, vacuums and tiny nets: the new fight against microplastics

Is chewing gum made of plastic?

Some plastic with your tea? | Newsroom - McGill University

A plateful of plastic: Visualising the amount of microplastic we eat

Plastic-Free Tea Bags In Australia

Scientific review reveals the chemicals migrating from PET drink bottles

Recycled plastic bottles are leaching harmful chemicals into drinks

National Primary Drinking Water Regulations

Single-use plastic and your health: can PET plastic cause harm?