Microplastics are a hot topic of conversation, with many people worried about the impacts they might have on our health. Over the last couple years, many studies have been done to determine what these impacts might be - but it's hard to give a straight-forward answer to this fast-evolving topic.
What do we mean by microplastics?
Anything plastic that is smaller than 5mm (0.5cm) across. These could be particles that were manufactured to be that small or have sloughed off from larger items through some kind of mechanical or chemical process. Nanoplastics, which are smaller than 1 micrometer – or 0.001mm (that’s very small!) – are especially concerning because they can enter the cells that make up our bodies.
Where do they come from?
We encounter microplastics and nanoplastics in almost every part of our lives – they are in trash, fabrics, cosmetics, cleaning products, seafood and many, many other everyday things.
There’s a lot of news about microplastics in humans; should we be worried?
Probably, though it’s hard to say what impact they are having. Here’s what we do know – according to a piece published by The Washington Post at the beginning of this year, microplastics have been found in many parts of our bodies, including testicles, kidneys, livers, placentas and – most recently – our brains. Oh, and a toddler’s poo.
- This animal eats plastic and poops it out at the bottom of the sea – and scientists just recorded it
Some scientists have estimated that the average human brain is 0.5% microplastics by weight (or 7g), equivalent to one plastic spoon. But other researchers have challenged this finding, saying that fat in the body can be misidentified as polyethylene and that the brain is roughly 60% fat. One scientist said there were serious doubts over more than half of the studies on plastics in human tissues.
How much are we taking in – and how?
One study published in 2021 estimated that on average, globally, one person may ingest between 0.1-5g of micro plastics every week – we take them in mainly through what we eat and breathe, though some research suggests that skin contact could be a vector as well. They have been detected in food packaging, drinking water, air (especially in urban areas), and household dust.
Are microplastics impacting our health?
It’s highly likely. One study exposed mice to tiny particles of polystyrene and found they were more likely to exhibit symptoms that looked like Alzheimer’s. In another one, people suffering from dementia had three to five times the quantity of microplastics of those who weren’t. However, scientists cautioned that this doesn’t mean the microplastics were responsible for the condition – it could be that brains with dementia were at greater risk of building up levels of microplastics. We just don’t know.
Any other health conditions I should be aware of?
A study published in 2024 found micro and nano plastics were a risk factor in heart disease – patients with these particles in their arteries were found to be at greater risk of heart attacks and strokes.
Is the problem getting worse?
It could be. One study compared the brains of people who died in 2024 with those who died in 2016 and it found concentrations of microplastics had increased by 50%.
Is there anything I can do to avoid microplastics?
Well, probably not much. A plastic cup or mug with a hot drink is more likely to contain microplastics than one with a cold drink, though perhaps the lesson there is to avoid drinking out of plastic cups if you can. Highly processed foods will contain greater concentrations of micro plastics than meals made out of fresh foods such as vegetables and fruit, but these are frequently contaminated, too.
Are microplastics found in wildlife?
Sadly, yes. They have been found in the intestines of invertebrates, fish, turtles and many other large animals. Much smaller organisms such as plankton and algae also take them in, and they then pass them on up the food chain. Soil invertebrates such as earthworms and springtails have also been found to contain them. Microplastic contamination could be impacting “animal behaviour, population dynamics and ecosystem processes”, according to this research paper.
