Microplastics: Are we facing a new health crisis – and what can be done about it?

This article has been updated.

There's a growing body of evidence about how widespread microplastics have become – across land, sea and air – and the impact they could be having on human health. Some experts believe we are on the brink of a plastic health crisis.

In 2022, microplastics were discovered in human blood. Now scientists have found evidence of microplastics in our brains. To give some perspective, it is estimated that the average person can eat, drink or breathe between 78,000 and 211,000 microplastic particles every year.

Microplastics are pieces of plastic debris under five millimetres in length, explains the US National Ocean Service.

Some – such as microbeads, typically found in cosmetics and toiletry products – are designed to be small, while other plastic gradually breaks down to this size.

Although microbeads are now banned in many countries, the problem of plastic pollution is far from resolved. According to UNEP, up to 23 million tonnes of plastic waste leaks into the world's water systems every year.

Microplastics come in various forms, each with its own sources and environmental impacts. Primary microplastics are intentionally manufactured small plastic particles, including the microbeads used in cosmetics and the plastic pellets (nurdles) used in industrial manufacturing.

Plastic glitter, often made from polyethylene terephthalate (PET), is another common primary microplastic that poses environmental concerns.

Microfibers, typically shed from synthetic clothing during washing, are a significant contributor to microplastic pollution.

Secondary microplastics form from the breakdown of larger plastic items - such as abandoned fishing gear, plastic litter - through weathering and environmental exposure.

Some researchers also recognize nanoplastics, which are even smaller particles, though their specific impacts are still being studied.

These tiny particles are often small enough to pass through water filtration systems, and we can then unknowingly ingest them.

Equally, research has shown that such microplastics can be transported in the atmosphere, spreading to even the remotest corners of the Earth.

In the ocean, these particles can be eaten by marine life – from fish to shellfish. A 2022 study found broken-down microplastics in blue mussels off the Australian coast. The research added to the findings of an earlier study that concluded, 'if you eat muscles, you eat microplastics'.

And it's not just marine life that could be affected. Microplastics have been found in foodstuffs including honey, tea and sugar, as well as in fruit and vegetables.

Microplastics are also making their way onto farmland through sewage sludge being used as fertilizer, according to a Cardiff University study. The BBC reports that much of this will then end up in waterways as a result of runoff from the top layer of soil.

It's still unclear what the environmental and health impacts of microplastics could be. However, a recent study points to the possibility that they can increase the likelihood of heart attack, stroke, or death. Another links microplastics with inflammation and noncommunicable diseases.

Some researchers say we're in the lull before the storm and that "alarmingly, a turning point is expected in the future, signalling a significant microplastic pollution outbreak if effective measures are not taken to mitigate it".

With pollution ranked in the World Economic Forum's Global Risks Report 2024 as the 10th greatest threat to the world in the short and long term, concerted and urgent action is required if the world is to meet Sustainable Development Goal 14 to “prevent and significantly reduce marine pollution of all kinds” by 2025.

Certain measures are already in place. The Microbead-Free Waters Act of 2015 prohibits the manufacturing, packaging and distribution of rinse-off cosmetics and non-prescription drugs (such as toothpaste) containing plastic microbeads.

In March 2022, at the UN Environment Assembly, 175 nations agreed to end plastic pollution. A legally binding agreement – addressing the issues of single-use plastic and recycling technology, among others – will be drawn up by the end of 2024. In 2023, the European Union banned the sale of loose plastic glitter.

In the meantime, individuals and companies are coming up with innovative solutions.

For example, a team of researchers at Sichuan University has developed a tiny robot fish that can collect microplastics. The BBC reported on a removal method using vegetable oil, iron oxide and magnets. Following 5,000 tests, the technique was found to be 87% effective at extracting microplastics from water.

Operation CleanSweep and the US Environmental Protection Agency’s Trash-Free Waters initiative are both working to remove harmful human-made rubbish from the ocean. The latter just produced the third part of its ‘National Strategy to Prevent Plastic Pollution’.

The Forum's Global Plastic Innovation Network champions 18 different solutions to the plastic waste problem, including Wasser, which has developed a system that can remove 95% of microplastics from water, and Orgro Fibre, which makes biodegradable sapling bags to replace the single-use plastic ones commonly used in gardening centres.