We keep hearing the word “microplastic” in our foods, seas, and ground, but if they do not react with most chemicals, why are they a problem in our bodies? Wouldn’t they just ignore them?
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Well, they don’t. They sit around. Despite being “everywhere” these plastics are not causing immediately apparent problems.
But they are places that they shouldn’t be, and failing all else they can be mechanical problems – physical debris located places it shouldn’t be.
And because they’re everywhere, smaller more subtle interactions such as being almost but not perfectly inert start to take effect.
Because they don’t need to react chemically to harm us..
Same way salt can block plants from getting water from soil, microplastics can physically block cells and their input/output
There inertness is precisely the problem… they get stuck in places in our body they shouldn’t be and there is no way to remove them because they’re chemical inertness prevents the body’s filtration and detoxing systems from (kidney+liver) getting rid of them. Think about drugs for example, your body can eventually get rid of it coz if it’s reactivity but it can never get rid of micro plastics, and there build up can eventually lead to mechanical issues in the body possibly
They kinda just stick around and while there are no apparent immediate issues we don’t want to wait till something pops up in say 40 years. Similar thing happened with deet, it was sticking around in everything and while it caused no issues in those places we could not let it keep going until it did cause issues.
The idea of microplastics is relatively new. We discovered them around 20 years ago.
So it’s possible they are inert and do not pose a problem, but we’re not sure we understand them enough yet to say that for sure.
Sometimes people are afraid of things they don’t understand. Some people also make more money when your read things they write. So they write things to make people more afraid, so they read more of these things.
This is one reason it’s important to learn to read and think about what scientists write, so you can decide on your own whether the people telling you that you should be afraid are wise or not.
*Mostly* chemically inert is not the same as *entirely* chemically inert.
Consider radioactivity. Which isotope do you think is more dangerous, uranium-239 with a half life of ~24 minutes, or uranium-238 with a half life of ~4.5 billion years? You might initially think the U239 is more dangerous because it’s much more unstable, more radioactive. It will give you a much much higher dose of harmful radiation in a few minutes!
However, that high instability also means that it becomes safe very quickly (ignoring the products that it breaks down into, which I have not bothered to look up – the point of the analogy is that the U239 is gone). The U238 will poison you more slowly, sure, but it also sticks around *forever*.
Similarly, most plastics most of the time are pretty stable and don’t react to much. But that means they don’t break down quickly. They stick around, and your body has no way to get rid of it *because* it’s so stable. However, some of it still does break down and those products may be harmful. One trend seems to be plastics that mimic hormones (particularly estrogen) in our bodies, which can really throw off how we function.
Since our bodies can’t get rid of the plastics, because they’re too stable, they stay in our bodies and break down slowly.
This is also true of plastics in the environment. They don’t break down so they just accumulate, causing all sorts of problems. Some of them aren’t chemical reactions, they’re just like, fish eating plastic and starving to death because they can’t digest the plastic. Or, organisms colonizing on floating plastic and building populations much higher than the environment can sustain.
What goes in, often comes out. If it doesn’t, then it’s either stuck or incorporated into the body (i.e. some chemical reaction occurs). The problem with highly stable compounds entering the body is due to accumulation over time and chronic exposure. This is a possible issue with microplastics for this same reason. Ingesting it as a small particle can lead to accumulation in the small nooks and crannies of our digestive system, and perhaps even our respiratory system if airborne (see: silicosis).
Also lots of the additives to plastic aren’t inert. BPA is biologically active and resembles the action of sex hormones. Regulators spent years trying to get rid of it with some success. So plastic manufacturers added a new chemical that looks and acts very similar to BPA but isn’t technically the same thing. The long process simply restarts. The real problem is business that doesn’t care about its impact on people at all. See the talcum powder incident for further evidence. The business culture in this country is counter productive to everyone
A lot of rocks are also chemically inert, but if you eat sand or breathe rock dust you’re going to have a problem. A chemically inert object in your body can hurt you if it’s solid and there isn’t supposed to be a solid object where it is.
Also the estrogen receptor has less discerning taste than most receptor proteins, so it doesn’t take much for a chemical to look like estrogen to your body, and some plastic additives fit the bill.
Asbestos is basically chemically inert.
But it’s physically still very damaging.
Even carbon nanotubes are basically inert, but we strongly suspect there will be problems with them because they persist in the environment and are incredibly resistant to breaking down – precisely because of the structural physical strength they have and that’s what we want to utilise them for.
You don’t have to be chemically reactive to be damaging. Swallowing string is harmful to you. Plastic, to small animals, is like string that never breaks. Think fishing line – plastic string, basically.
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