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We know plastic is harming our oceans… but what is it doing to our health?

Plastic 
Microplastic is finding its way onto our plates, according to several new studies

Back in the early Nineties, when convenience culture exploded, my mother took a rather more cautious view. She refused to buy boil-in-the-bag meals, drink anything from a plastic bottle or use a microwave.

And while everybody else on our road began buying milk in large, plastic containers from supermarkets, she remained steadfastly loyal to the milkman, who continued to deliver our milk in glass bottles. 

Teased by her friends, her reasoning was, “you just don’t know what all that plastic is doing to your health”. Fast forward 30 or so years, and it’s a question that needs answering urgently.

Last week, researchers from the World Wide Fund for Nature (WWF) found the average person unwittingly eats up to 102,000 pieces of microplastic (tiny pieces smaller than 1mm) each year – the equivalent of a credit card-sized amount of plastic each week – with around 90 per cent coming from water and the rest via food and other drinks.

Alec Taylor, Head of Marine Policy at WWF, said: “Plastic is polluting our planet in the deepest ocean trenches, but now we know that it’s also polluting our own bodies, through the food we eat and the water we drink. This report must serve as a wake-up call to the UK Government – we don’t want plastic in our oceans, and we don’t want it on our plates.”

To reduce plastic exposure, carry loose fruit and veg in paper bags Credit: Alamy

We ingest microplastics through a variety of means: they can leach from plastic containers into our food and drink; and discarded plastic grinds down over time into small pieces that end up in our water supply, or get eaten by animals, fish and shellfish, which then get eaten by us. 

The WWF findings follow another study, from Penn State Behrend University in the US, that analysed samples taken from 259 bottled waters sold in various countries and found that 93 per cent contained microplastics. Many of which weren’t very micro at all.

“Some were definitely visible without a magnifying glass or microscope,” said the study author, Sherri Mason, whose findings have led to the World Health Organisation (WHO) announcing plans to investigate the safety of bottled water, with results expected at the end of this year.

“People are aware of plastic bags floating around our oceans, but they’re less aware of how that plastic is making its way back to us through our diet,” says Michael Coleman, professor of toxicology at Aston University, Birmingham. “And we’re only just beginning to understand what happens when it does.”

Coleman says while the larger microparticles go straight through our system, the smaller ones cause him more concern. “There’s evidence the really tiny particles enter our cells. And like an unwelcome intruder that causes a homeowner to dial 999, they cause an immune response in the body, which can cause inflammation and other issues.”

Although the long-term health effects of plastic consumption are unknown, some studies have shown it may produce inflammation of the respiratory tract, and some plastic containing chemicals have been shown to influence sexual function, fertility and increase the risk of certain cancers.

Studies show there are 20 times more plastic particles per litre of bottled water than tap Credit: Jacob Lund/Shutterstock 

“Microplastics may also have a Trojan Horse capability,” says Coleman, who says they can enter the body under the guise of hormones such as oestrogen, which they mimic.

Endocrine disrupting chemicals (EDCs) are widespread and found in children’s toys and plastic bottles, and may interfere with hormone function.   “And these chemicals are persistent and difficult to break down. Plastic was built to be sturdy and last a long time, after all, because we didn’t want our groceries spilling out onto the street like they did when carried in paper bags.

"But is there a health cost to their sturdy nature? We don’t know, but scientists are trying to find out.”

Alistair Grant, a professor of ecology at the University of East Anglia, is less concerned: “Plastic is everywhere: it gets thrown away and breaks down; plastic fibres come off our clothes and go into waste water. There’s no avoiding it.

“In terms of concentration, there are roughly 20 times more plastic particles per litre in bottled water than tap, which is due to the manufacturing process. Huge blocks of plastic are turned into water bottles and tiny bits of plastic break off. So if people want to reduce their plastic intake, they should avoid bottled water.

“However, I think the important message to take away is we’re talking about a relatively small amount of particles here, and there’s no proof they’re causing us any harm. Studies have tested the effects of plastic particles on a range of animals and found it takes a huge concentration to have an adverse affect. Certainly much higher than you’d find in the environment. And remember, there are strict guidelines surrounding plastic food and drink containers.

“This study doesn’t concern me. What concerns me is the effect plastic is having on the environment, and the fact 14 per cent of deaths in this country are obesity-related. That should concern people more.”

Professor Coleman, however, disagrees: “Avoiding plastic is no longer just an environmental issue, it’s becoming apparent it needs to be a health one, too.”