From Antarctic ice to the deepest ocean trenches, microplastics are everywhere.
These minuscule pieces of waste plastic, sometimes thousands of times smaller than a human hair, have infiltrated our kitchens too and in ways that might surprise you.
But is a little bit of plastic really so bad for us?
Discussions on the topic remind John Boland, professor of chemistry at Trinity College Dublin (TCD), of the early debates around smoking.
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“We have a link, or a correlation, between the accumulation of micro and nano plastics in organs in the human body with certain medical conditions, but we don’t know that it’s causal,” he says.
“But it’s absolutely clear that there are very significant accumulations of plastics in the human body. The amniotic fluid of any pregnant woman will contain micro and nano plastics. The meconium, or first poo, of a newborn baby will invariably have microplastics in it too.”
Prof Boland cites an Italian study of cardiac patients published in the New England Journal of Medicine where the plaque lining their arteries was found to contain a very significant amount of micro and nano plastics.
“Those patients with higher levels had much poorer outcomes,” he says.
Tiny plastics can damage our brains too and may be contributing to the increasing global levels of Alzheimer’s and Parkinson’s disease, according to a TCD study published in September.
“Plastic has only been around for 60 or 70 years, but we’ve seen a dramatic increase in neurological diseases that can’t be explained by genetics or population growth alone,” said associate professor of biochemistry Gavin Davey, of the study, published in the Journal of Hazardous Materials: Plastics.
[ Microplastics: how dangerous are they and how can we reduce our risk?Opens in new window ]
It’s all chastening stuff, but there is some good news in the knowledge that you can take a few steps at home to help minimise your household’s exposure to microplastics, starting with how you prepare your food.
Heating food
The bottom line here is to avoid using plastics when preparing food at high temperatures. The effect of heat and steam on the plastic makes for a particularly nasty cocktail, says Prof Boland.
“It’s the combination of high temperature, steam and plastic that really promotes the release of microplastics, and this is a huge problem,” he says.
Plastics contain polymers, and also lots of small chemical additives that help plastic items keep their shape and flexibility and prevent degradation. In heat and steam, these same chemical additives leach out in huge quantities.
“So you are not just getting plastics, you are also getting these small chemical molecules going into your food and that’s the real problem,” he says.
Chopping boards
That we ingest plastics from food when we prepare it on plastic chopping boards makes sense. We may not see them, but the chopping action is releasing tiny plastic shards from the board onto our food.
Annual exposure to microplastics of up to 50.7g (1.7oz) from plastic chopping boards was estimated by one US peer-reviewed study in 2023.
So get rid of your plastic chopping board, chop chop. Swap it for a glass one, or a board made from a single piece of hard wood that has not been glued, experts say.
Plastic kettles
“People don’t actually rinse their kettles, so the reality is you are often boiling the same water over and over again,” says Prof Boland.
“If you look at the bottom of your plastic kettle, you’ll notice little things floating about in it. Plastic kettles are one of the biggest generators of microplastics and chemical additives in our kitchens.
“Because you don’t completely clean it, a plastic kettle is particularly problematic,” he says. “Moving away from a plastic kettle will provide huge benefits to you.”
Switch to a metal kettle, or a glass one, though even some of these have plastic components too, he says.
Microwave meals
Plastics in the microwave are another thing to be avoided - so if you’re partial to a supermarket ready meal, be careful. The effortless preparation is a big part of the sales pitch - just pierce the film, whack the plastic tray in the microwave on full power and it’s done.
But this heat and plastic combo isn’t good, says Prof Boland.
Plastic containers and bottles are made by putting melted plastic into a mould which is then cooled. Heat and steam from cooking however causes the polymers and chemical additives used to make plastic flexible to seep out in huge quantities.
“Put any of those containers in a microwave with any kind of steam and you are actually adding energy to the plastic which allows the microplastics and chemicals to leach out,” says Prof Boland.
Takeaways
Heating those thin plastic lunchboxes you sometimes get with a takeaway are just as bad. Noodles in a pot are another example.
Conventional ovens can have a similar effect on plastic, though with less of the steam element than microwaves.
If you are heating a ready meal or takeaway, tip it out of the plastic tray or plastic lined carton and into a glass container and heat it that way, says Prof Boland.
Batch cooking is the hallmark of an organised household. But if you batch freeze meals in plastic bags or lunchboxes, take them out of the plastic before heating them to lessen microplastic contamination, he adds.
“I would completely avoid putting any plastics in the microwave. Period.”
Water bottles
Plastic water bottles come under fire too. Swapping a bottled water habit for a reusable bottle is a great move for the environment, but if your drinking bottle is plastic, be careful about how you wash it.
“If possible, avoid plastic water bottles. Period,” says Prof Boland. “And if your kids have one for school or sport, be mindful of how you wash it.”
“Depending on the cycle you use, the dishwasher drying process can drive the release of microplastics and additives to the inside surface of the bottle, so if you do clean it in a dishwasher, you should rinse the bottle vigorously before you refill it with water,” he says.
Metal-lined bottles with vacuum walls are preferable, he adds.
Cookware
While cookware with non-stick coatings isn’t his specific area of study, and there is no evidence yet they cause human harm, the ‘forever chemicals’ used in the manufacture of these items are notable, says Prof Boland.
When his pans start to flake and lose their coating, he always switches to a new pan.
“There are cast iron and stainless steel pans that are great, but they are expensive and can be hard to maintain,” he acknowledges.
Be aware
The infiltration of micro and nano plastics is “scary”, but we have to try to manage it, says Boland.
“Plastics are exceptional materials with wonderful properties, but unfortunately the way we make them is susceptible to degradation,” he says, calling on regulators to push manufacturers to do things differently.
“It is possible to do it. It will be more costly, the rate of production will be much lower, but at the moment, we have a couple of billion plastic water bottles manufactured every day, and that’s just crazy.”
In the meantime, while governments talk about regulating plastic production and lobbyists lobby them not to, you can take action in your kitchen. Switch your plastic chopping board and kettle, ditch the microwavable tray dinners and bring that old pan to a civic amenity site today.
