The first two articles established that plastic is everywhere, including inside you. The question that matters is whether that does any harm. The particles themselves are one concern. The chemicals added to plastic to make it soft, hard, coloured or fire-resistant are another, because they are not locked in and they leach out.
This article separates what has been proven from what is still being argued about. There is a lot of the second.
There are two separate things going on, and they are often muddled together in the news.
Some of the additives behave like hormones. Some are known poisons. The particles carry the additives with them, so you get both.
This is where the evidence is piling up fastest.
The last point is a measurement, not an explanation. The paper that reported it does not blame plastic. But the phthalates used to soften PVC are known to suppress testosterone production, and the timing fits.
A Netflix documentary, The Plastic Detox[6], follows couples who cut plastic out of their lives in order to conceive. It is persuasive, but three couples is not a trial. The honest position is : the plastic is in the reproductive organs, that is proven; whether it is what is causing the decline is not yet proven.
Yes. In 2025 the New Mexico team measured plastic in the brains of 52 people who had died in 2016 and 2024. The 2024 brains held about half a percent plastic by weight, roughly a teaspoon, and about 50% more than the 2016 brains. The brains of people who had died with dementia held several times more again. Most of it was polyethylene, the plastic of bags and bottles, in the form of tiny shards.[7]
Animal studies show how it gets there. Nano sized polystyrene fed to mice was found in the brain within two hours; a coating of blood proteins lets the particle through the blood-brain barrier.[8]
Does it do any harm there? Nobody knows. The dementia figure came from only twelve brains, and dementia itself makes the blood-brain barrier leaky, so the plastic may be a result of the disease rather than the cause. Other chemists have challenged the teaspoon figure, pointing out that fats in brain tissue can mimic polyethylene in the test used[9], and the authors have conceded the point may have merit.[10] In mice, particles in the blood have been seen to clog the fine capillaries of the brain, but mouse capillaries are far narrower than ours.
So : plastic in the brain is real. The amount is disputed. The harm is unknown.
Hormones work by fitting into a receptor on a cell, like a key in a lock. An endocrine disruptor is a chemical that is the wrong key but fits the lock anyway. It either turns the lock when it should not, or sits in it and stops the real hormone getting in.[11]
In 2023 the European food safety authority cut the daily amount of BPA it considers safe by a factor of twenty thousand, and stated that current dietary intake is hundreds of times above it.[12] Food Standards Australia New Zealand disagrees and says intake here is low.[13] Germany's regulator thinks the European figure is a thousand times too strict. So the science of how much is still a fight. The mechanism is not.
Products labelled BPA-free usually contain BPS or BPF instead. These are the same molecule with a minor change and, in the laboratory, are just as hormonally active.[14] The label is marketing.
Additives migrate faster when the plastic is warm, and the studies put the threshold surprisingly low.
It goes both ways. The spices migrate into the plastic as well. The turmeric container in the photo is stained right through the wall, and what the photo cannot show is that the inside surface is pitted. Plastic that has been eaten into is plastic that has gone somewhere, and the only place it can have gone is into the spice.
The inside of a parked car in a Brisbane or Auckland summer easily passes 50°C. Do not leave a plastic bottle in the car and drink from it later. Do not store spices, oils or anything acidic in plastic near a heat source. Do not reheat food in plastic.
PFAS (per- and polyfluoroalkyl substances) are a separate family of several thousand chemicals built around a carbon-fluorine bond, the strongest bond in organic chemistry. Nothing in nature breaks it, so they are called the forever chemicals. They have been made since the 1940s for non-stick cookware, grease-proof food wrappers and takeaway packaging, waterproof clothing, stain-resistant carpet and firefighting foam. They are not hormones, and they are not the same thing as the hormone disruptors above, although some of them interfere with hormones as well.
Their link to plastic is direct. Teflon (PTFE) is a plastic and is itself a PFAS. The others are coatings applied to plastic and paper.
The US EPA lists the effects found in people : reduced fertility, high blood pressure in pregnancy, low birth weight, weaker response to vaccines, raised cholesterol and kidney and testicular cancer.[19][20] The Australian Government's expert panel is more cautious and says the evidence of actual disease is limited.[21] Both agree the chemicals accumulate in the body and stay there.
In 2025 Australia cut its drinking water limit for PFOS, the best studied one, to 8 nanograms per litre, about nine times stricter than before.[22] New Zealand has banned PFAS in cosmetics from the end of 2026, the first country to do so.[23]
In 2024 an Italian team examined the fatty plaque removed from the neck arteries of 257 patients. Plastic was found in the plaque of 58% of them. Over the following three years, the patients with plastic in their plaque had four and a half times the rate of heart attack, stroke or death of those without.[24]
It is one study, of people who were already ill, and it shows an association rather than a cause. It is also the strongest signal yet of plastic particles doing measurable harm to people.
The proven carcinogens are the building blocks, not the finished plastic. Vinyl chloride, from which PVC is made, causes liver cancer and is in the highest category.[25] Styrene, from which polystyrene is made, is a probable carcinogen.[26] Both findings come from factory workers breathing the raw chemical; the finished product contains only traces.
The particles themselves have not been classified as a carcinogen by anyone. The World Health Organisation said in 2019 that microplastics in drinking water do not appear to be a risk at current levels, then asked for more research.[27] Cell and animal studies show inflammation, which is how many cancers start, but that is as far as the evidence goes.
Here the harm is not in dispute.
Plastic harms wildlife by being eaten and by entangling. In people the particles have been found in blood, lungs, arteries, testes, ovaries, placentas and brains. Presence is proven. Harm is being argued about, with the heart study and the fertility figures as the strongest signals so far. The additives are a different matter : the hormone disruptors are known to work, and PFAS are known to accumulate.
You cannot avoid plastic. What you can do is keep it cool, keep it away from heat and acid, keep it out of the microwave, and not leave the water bottle in the car.
Ocean pollution, plastic litter - deposit
Plastic bottle stained through by turmeric - our kitchen