Plastics have long been dismissed by their critics and completely avoided in the modern world. Now, new research is uncovering an increasing range of health risks that they pose.

The normal definition of microplastic is plastic fragments or fibres that measure 5mm or less. These are either a material that is already micro-sized when it enters the environment or, far more commonly, the result of the breakdown or shedding of a plastic material. Sometimes they can be added to products, as in the case of plastic microbeads added to cosmetic products.

Microplastics may contain any of more than 16,000 different plastic chemicals, of which at least 4200 (26 per cent) are considered “highly hazardous” to human health and the environment, including PFAS, bisphenols and phthalates. In addition, microplastics have a tendency to absorb and concentrate harmful pollutants in the environment.

This form of human-generated contamination is so pervasive that it is found in environments that would otherwise be considered pristine, such as the peaks of the highest mountains, Antarctic Sea ice, the North Pole and the Mariana Trench, the deepest point in the world’s oceans. It has colonised everywhere in the world, to a greater or lesser concentration, and this includes the human body.

The role of the plastics industry

In the period following World War II, plastic took off, aided by a consumer boom, coupled with industry-driven messaging encouraging a wasteful shift towards single-use disposables. At the end of life, most is landfilled or incinerated via waste-to-energy, a type of power generation that is more carbon-polluting than burning coal. The average global plastic recycling rate remains under 10 per cent.

More important from a microplastic perspective is the roughly 0.5 per cent that ends up in the oceans. Most of this problem occurs in Southeast Asia, with the Philippines in particular being a global blackspot. To tackle the problem at its source, the amount of plastic packaging could be reduced, waste collection could be improved, and more recycling infrastructure that serves poorer countries could be established. There are major differences between rich and poor countries in how plastic waste is managed. Among OECD (Organisation for Economic Co-operation and Development) nations, including Australia, the UK and Japan, 2019 figures showed that an average 6 per cent was “mismanaged and uncollected litter”, compared to 39 per cent outside the OECD.

Meanwhile, plastic production has doubled in the last 20 years, in an exponential growth curve, and an estimated 99 per cent is derived from fossil fuels. Production of virgin plastic was responsible for an estimated 5 per cent of the world’s greenhouse gas emissions in 2019, a share that is on track to grow dramatically.

Global plastic waste totals 400 million tonnes per year, and current trends would result in this figure nearly tripling to 1100 million tonnes by 2050. This issue is now being framed as a “plastic pollution crisis”.

In November 2024, negotiations on a global plastics treaty kicked off in the South Korean city of Busan, initiated by the United Nations. So far, no consensus position has been reached, largely due to resistance from oil producers such as Saudi Arabia, Russia and Iran. Yet more than 100 countries support commitments to reduce plastic production.

Where do microplastics originate?

Plastic takes up to 500 years to decompose and, when this does occur, it breaks down into ever smaller pieces instead of disappearing.

The Great Pacific Garbage Patch is concentrated in two primary locations, the more well-known of which is roughly halfway between California and Hawaii. Nearly all of it is plastic, which is slowly broken down, to form microplastics, and smaller nanoplastics that are less than one micrometer or micron (a thousandth of a millimetre) in size. The soup-like consistency of this limbo for unwanted plastic makes collecting it a formidable challenge. The accumulation of plastic fragments has been found to be growing at a rapid rate.

Tracing the origin of oceanic plastic particles, several important sources can be identified.

Cosmetics companies add plastic microbeads to certain products such as face wash and hand soap due to their abrasive or exfoliant properties. Being deliberately added, they are the easiest of all to avoid, if shoppers take time to look at the ingredient lists.

Perhaps surprisingly, paint, largely in the form of polymers used in binders, has been identified by a 2022 study as the primary source of microplastics entering waterways and the oceans, constituting 58 per cent.

An important source of ocean microplastics is the fibres from synthetic clothing (polyester, acrylic and nylon) and part-synthetic blends. These are emitted during washing, especially from the first few washes. To reduce these releases, suggestions include washing clothing less, washing on cold, avoiding purchasing synthetics, using a Guppyfriend washing bag or installing a microplastic filter on the drain hose line.

Tyre wear is another important microplastic generator, responsible for an estimated quarter of these particles entering the environment. Heavier vehicles such as four-wheel drives and electric vehicles tend to do more shedding. Tyre designers have been working on prototypes that are less prone to this problem.

Plastic artificial turf releases plastic fragments and is potentially linked to cancer and other serious health issues. Guppyfriend sells special drain filters that are installed on the edges of sports fields with synthetic turf.

Nurdles are tiny, lentil-sized plastic resin pellets used as a manufacturing feedstock, which are microplastic-sized when they sit in storage at plastic factories. Due to their tiny size, it is easy for some to escape into the surrounding environment. The group Environmental Justice Australia has drawn attention to the accumulation of nurdles in Melbourne’s Port Phillip Bay.

Human exposure

Three primary routes for people to take in microplastics are via food, drink and breathing in airborne particles.

When it comes to eating, exposure sources include plastic packaging, food-storage containers, utensils and plates. A 2025 Chinese study on plastic takeaway containers found that exposure may alter the gut biome, potentially triggering inflammation linked to a higher risk of heart failure.

Recommendations for minimising food exposure include:

• Swap plastic food-storage containers with glass.
• Avoid using plastic takeaway containers or otherwise transfer the food into a non-plastic container when you get home.
• Replace plastic cutting boards with wood or bamboo.
• Swap plastic utensils with wood or metal.
• Don’t heat plastic in the microwave. Always remove food from a plastic container before heating.
• Don’t reuse single-use plastics for food or drink purposes.
• Wash plastic containers by hand rather than in a dishwasher, as this slows plastic degradation.

Yet microplastics are also getting into foods before they are packaged. Investigations of seafood found these particles in 99 per cent of items sampled, and most were textile fibres. Levels can be reduced by rinsing the seafood product before preparation. Another study looking at fruit and vegetables found carrots to be the most contaminated vegetable, while apples were identified as the most contaminated fruit.

Plastic-bottled water has more nano and microplastics (NMPs) than water from the tap and most of these originate from the bottle itself. Similar issues also apply to other plastic-packaged drinks, including foil-lined liquid paperboard that has a plastic layer in contact with the liquid.

Some ideas for reducing intake via liquids are:

• Consider a high-quality water filter that can deal with particles down to 0.5 microns in size, removing all microplastics and the largest nanoplastics. Cheaper water filters are not as effective but do reduce microplastic levels.
• Boil and then filter tap water to remove up to 80 per cent or more of NMPs, with better outcomes in hard water (mineral-rich) areas. This works even with a simple coffee filter.
• Use a kettle that has a minimum of plastic in contact with the water.
• Tea bags are often strengthened using plastic fibres, although some companies have gone plastic-free. Take a precautionary approach via loose-leaf tea and ask the manufacturers about plastic, as this demonstrates that people have concerns.
• Take-away coffee cups are plastic-lined and release exceptional quantities of nanoplastic particles. Fortunately, metal reusable cups are available, which bypasses this issue.
• Use glass or silicone baby bottles.

An under-acknowledged source is via airborne exposure. Due to their tiny size, microplastics, especially the fibrous type, are inclined to float in the air. Researchers at Griffith University in southeast Queensland investigated seven diverse indoor environments, including a couple of domestic dwellings, and found that levels were far higher than for outdoor air. Most of these particles were found to originate from rugs, carpets, curtains and clothing. Experts recommend frequent vacuuming using an appliance with a HEPA filter and removing outdoor shoes when walking inside the house.

Health risks

While many of these plastic fragments are excreted, some stay in the body. They have been discovered throughout the body, including in the lungs, blood, placenta, breast milk, heart, liver and kidneys. At least in trace amounts, they are most likely present in everyone on the planet.

The health ramifications of this are only slowly being understood, but a picture is emerging.

Due to their tiny size, nanoplastics are capable of entering cells and affecting how they function, including by depositing endocrine-disrupting xenoestrogens. In a laboratory setting, effects on cells included allergic reactions and cell death.

NMPs can cross the blood-brain barrier and the smaller they are, the easier it is to cross. An American 2025 study found brain concentrations to be seven to 30 times higher than in the liver and kidney. Brains were found to consist of about 0.5 per cent microplastic by weight.

The same study found that over the eight years between 2016 and 2024, average concentrations of microplastics in brains had increased by 50 per cent.

Inflammatory effects on tissues may include a contribution towards inflammatory bowel disease (IBD). People with IBD were found to have 50 per cent more microplastics in their faeces.

Another study looked at 312 people who had fatty deposits removed from the carotid artery (in the neck area) and identified microplastics in nearly 60 per cent of cases. After tracking these individuals for nearly three years, those who had microplastics were 2.1 times more likely than the non-microplastic group to have a stroke, heart attack or die.

Microplastics were discovered in ovarian follicular fluid, in 14 of 18 women tested, with potential impacts on fertility.

These plastic particles may alter gene expression and may introduce epigenetic changes that continue through the generations.

Cleaning up

When confronted with this somewhat nightmarish situation, there is a tendency to throw up your hands in despair and give up. Another is to rely on the fact that plastic has been in everyday use for about 75 years and fall into complacency. Neither is very helpful.

At present, there is very limited government regulation. Some countries, including New Zealand, have banned microbeads, and Australia has largely phased them out. The EU has introduced a ban on microplastics being intentionally added to products.

Water treatment plants filter out most, but not all, microplastics. Experimental traps that remove some of them have been trialled on the Yarra and Maribyrnong Rivers in Melbourne. Elsewhere, the use of a bubble curtain system has been found effective for diverting plastics, including as small as 1mm, into a catchment area to prevent them from entering the ocean.

The University of Hawaii has identified several fungi native to that state’s coastal zones that eat microplastics, transforming it into fungal material. Microalgae and invasive water hyacinths both capture microplastics in aquatic environments and remove them from circulation.

Anthocyanins are a group of flavonoid antioxidants that appear, based on animal tests, to counteract the effects of these particles on the male and female reproductive systems. The highest levels of anthocyanins are found in red, blue and purple fruit, mostly berries.

It isn’t possible to avoid microplastics, but exposure levels can be minimised. At a household level, there is a marked shift towards plastic-free living, making changes one at a time. While capturing what is already in the environment is a huge challenge, it is possible to curb future production of single-use plastics, with the proposed global plastics treaty an important step in the right direction.

Article Featured in WellBeing Magazine 218