What are microplastics?
Microplastics, as their name suggests, are very small pieces of plastic – tiny, insoluble plastic particles that have made their way into the environment. The conversation surrounding microplastics is still quite new (the word itself was only introduced in 2004) and many aspects of the subject remain mysterious, but studies have consistently shown that one thing is certain: microplastics are everywhere.
First detected in the 1970s, marine scientists estimate that the ocean alone now contains up to 51 trillion microplastic particles – more than 500 times the number of stars in the Milky Way galaxy. In terms of plastic content, that’s the equivalent of more than 60 billion 500mL plastic water bottles.
One of the challenges of studying and discussing microplastics is that there is no global consensus on exactly how to measure and categorise them; different organisations and studies have their own scales and requirements for different categories. Generally, however, the most popular ways to classify these particles are by size and by origin.
The names of different microplastics are often based on their size. “Microplastics” has become the catch-all term for discussing these plastic particles, but the word technically only applies to one of four categories. The naming and measuring conventions for this particular scale were modelled on the preexisting system for studying phytoplankton, a similarly microscopic and varied part of marine ecosystems.
- Macroplastics: plastic fragments larger than one centimetre, covering anything from bags and bottlecaps to entire plastic toys. Some studies categorise macroplastics larger than 20cm as “megaplastics”.
- Mesoplastics: smaller fragments sized 1-10 millimetres like resin pellets and flakes of plastic packaging.
- Microplastics: from tiny to microscopic, this term covers the range of 1-1000 microns. Plastic microbeads in cosmetic products are produced at this size, but a lot of microplastics are broken-down fragments of larger plastics.
- Nanoplastics: the most recently discovered and difficult to observe, these plastics are smaller than one micron.
When classifying plastics by origin, the main distinction is between primary and secondary microplastics.
Primary microplastics are tiny pieces of plastic that are still relatively intact. Fibres from polyester clothes, microbeads from cosmetic products and fragments of fishing nets/lines make up a lot of the primary microplastics in the ocean.
Secondary microplastics are fragments of larger plastic debris that have begun breaking down from exposure to the elements (oxygen, sunlight and friction from ocean waves). Rather than biodegrading like natural substances, plastic simply breaks apart into smaller pieces of plastic. Some partially degraded secondary plastics like PVC also become more toxic as they break down and react to solar radiation.
What kinds of plastic are in our water?
Microplastics have been accumulating in the environment for decades, but water treatment processes are generally quite effective for keeping plastic particles out of town-supplied tap water. Bottled water, however, often contains significantly higher microplastic levels than environmental samples. Studies of major bottled water brands have found several common plastics that are consistently present in plastic-packaged water.
Polyethylene (PE)
PE is the most widely used plastic in the world. Its flexibility and versatility make it a popular option for products like clear food wraps, shopping bags, and detergent bottles, but it can also be spun into synthetic fibres or modified to become a rubber substitute.
Polystyrene (PS)
Lightweight, well-insulated, and resistant to both water and bacterial growth, polystyrene has long been a go-to material for food-adjacent consumer goods like cups, trays and takeaway containers. Packaging/protective materials like styrofoam are also made from PS.
Polypropylene (PP)
PP is used to make products that need to be tough and heat-resistant but also lightweight and flexible. Dishwasher-safe food containers, car battery casings, shampoo bottles, and outdoor furniture are often made with PP plastic.
Polyvinyl Chloride (PVC)
One of the better-known acronyms on this list, PVC is a strong plastic typically used for piping and cable insulations. It also has several medical applications, often being used for creating blood bags and non-breakable containers.
Polyethylene Terephthalate (PET)
While the term “polyester” technically refers to a wider family of polymers, this substance is usually what people are referring to when they mention it. PET is another very common kind of plastic, being used for plastic bottles and packaging or spun into fibres for clothing and textiles.
Polycarbonate (PC)
This incredibly strong substance is a great option for products like aircraft windshields, bulletproof screens, and safety goggles – things that need to be both tough and transparent. Thanks to its UV-resistant properties, PC is also used in eyewear and roofing materials.
Polymethyl Methacrylate (PMMA)
More commonly known as Plexiglass or Perspex, this acrylic resin is a popular alternative to glass. PMMA isn’t as tough as PC but is typically cheaper and more rigid, making it a popular material for aircraft canopies, skylights, and lit-up advertising signs. Acrylic optical fibres are also made as a more flexible alternative to glass cables.
Polyamide (PA)
These nylon fibres are unique on this list in that they can appear naturally rather than being exclusively manufactured by humans. Natural polyamide substances include wool, silk, collagen, and keratin. However, mentions of polyamide will typically be referring to synthetic nylons rather than these natural fibres, used in various products as a softer, more durable, UV-resistant alternative to polyester.
Where are they coming from?
Microplastics make their way into our water supply from many different sources. Recycling keeps some plastic products in circulation, but most of the plastic produced around the world still ends up in landfills or accumulates in the environment.
In bottled water, the source of microplastic is no mystery – it’s the bottle. While the exact breakdown of plastics varies around the world, studies have consistently shown that plastic water bottles contain both PET and PP plastic particles, breaking down from the bottles themselves and their lids/caps respectively. Bottles imported from overseas typically have higher microplastic levels than Australian-packaged products, but all brands have significantly higher plastic content than mains water.
On a larger scale, most microplastics make their way into the water supply through a combination of erosion/abrasion and rain run-off. Road-marking paints and debris from worn car tyres join the dust of artificial turf and particles from shoe soles on our roads and pathways, all being swept away by the rain and carried into oceans and rivers. The same can happen to plastic fragments and fibres in landfills.
Eroded plastic can also come from wear and tear on polyester clothing, disintegrating products flushed down toilets and sinks, degraded fishing nets and even plastic components from pipes in water treatment plants.
Some plastic products are already small enough to be swept away as microplastics as soon as they’re made. Microbeads are small plastic particles (less than 1mm in diameter) manufactured for multiple industries and uses, often as a bulking agent or exfoliant in cosmetic products. They are typically made from PE, PET, PA, PP, and PMMA plastics.
Because products containing microbeads are often used in conjunction with water (rinse-off facial scrubs, toothpaste, etc.), they’re sent directly to our waterways after a single use and are small enough to slip through many protective filters. Several countries (including Australia) have made commitments to phase out microbeads across all industries, but they are still present in many products and already make up a significant amount of plastic pollution.
Why are they a problem?
This is another challenge from our limited understanding of microplastics; we know they’re accumulating inside our bodies, but we don’t fully understand what long-term health effects they might have. Most studies agree that while the exact impact of microplastic accumulation is unclear, further study is needed and it would be dangerous to assume no action is necessary.
One danger we do know about is the collection and transmission of toxic chemicals through biosolids (solid organic matter derived from treated sewage sludge and often used as a fertiliser). More than 95% of microplastics that pass through wastewater treatment are caught up in biosolids, along with any contaminants and toxins that bond with the plastic. The biosolids can then be used on agricultural land, introducing those contaminants to our food supply.
While the direct harms of microplastics are uncertain, their impact on our ecosystem as a whole is undeniable. Plastic particles in the ocean are being eaten by fish and other animals, leading to “false satiation” (their stomachs are being filled but there are no nutrients being supplied to their bodies). This has implications all the way up the food chain, both in disruptions to various animal populations and an increase in the amount of plastic we’re putting in our bodies from our food.
There are also concerns about animal suffering; videos of sea turtles and other marine animals trapped in plastic or struggling to breathe through painful plastic straws are all over YouTube and social media, clearly documenting the negative impact our actions are having on these creatures.
What can I do about it?
Plastic pollution is a serious global issue that will require major action from multiple countries to properly address, but there are ways each of us can both protect our families from microplastics and help contribute to reducing the number of microplastics that enter the environment. Here are four ways everyone can make a difference in the state of microplastic pollution around the world.
Eliminate plastic water bottles
PET plastic bottles are some of the largest contributors both to maritime plastic pollution and microplastic accumulation. Recycling a plastic bottle may get you a 10c refund, but you’re also consuming an entire credit card’s worth of plastic every month in the form of microplastics.
Water filtration systems are a great way to avoid plastic without sacrificing the taste of clean, chemical-free water. Whether you want the widespread benefits of whole-home filtration or are just looking for total confidence in the quality of your drinking water, Complete Home Filtration has solutions that make eliminating plastic bottles easy and affordable.
Avoid products containing microbeads
Despite efforts to remove these non-degradable, highly polluting plastic particles, microbeads are still present in a lot of cosmetic and self-care products. Check the ingredients list on your facial scrubs and toothpaste tubes for any of the plastics mentioned above (particularly PE, PET, PA, PP, and PMMA) and look for alternatives that use natural exfoliants like sea salt.
Wash your recycling
Less than 20% of recyclable plastics in Australia are successfully recycled. Households are the largest contributor to plastic pollution, and a lot of plastic waste comes in the form of otherwise recyclable products that have to be discarded because they’ve been contaminated.
You can maximise the success rate of your recyclable plastics by rinsing out soft drink and shampoo bottles, wiping down single-use containers and removing as much non-plastic matter as possible.
Use natural alternatives
From polyester fibres to plastic microbeads, many different products are adding microplastics to the environment through everyday use or wear and tear. Clothing without polyester can be more expensive than the mass-produced, plastic-based fashion, but opting for wool or cotton is a good way to use your own resources more deliberately in order to tackle microplastic pollution.
Second-hand clothing is also an excellent way to get affordable clothes while still opting for more natural materials. Buying from Op Shops and other charity outlets can maximise the positive impact of your purchase, both environmentally and socially.
