[dbingham]

Missing from this answer is the early evidence that they may be _very_ harmful. Early evidence suggests they are not non-reactive. They disrupt many of the body's systems in ways we're only beginning to understand.

> Various examples of damage caused by microplastics have been reported, such as microplastic accumulation in the bodies of marine and aquatic organisms (leading to malnutrition), inflammation, reduced fertility, and mortality. The threats that microplastics present to the human body have not yet been clearly identified. However, previous reports have shown that ultrafine microplastic absorption resulted in complex toxicity in zebrafish,2 and that microplastics under 100 nm in size can reach almost all organs after entering the human body.3 Therefore, concerns exist regarding the negative effects of continuous microplastic accumulation in the human body.

https://pmc.ncbi.nlm.nih.gov/articles/PMC10151227/

> Microplastics have been found in a variety of organisms and multiple parts of the human body. We emphasize the potential impact of microplastics on the early exposure of infants and the early development of embryos. At present, the toxicity research on microplastics show that the exposure will cause intestinal injury, liver infection, flora imbalance, lipid accumulation, and then lead to metabolic disorder. In addition, the microplastic exposure increases the expression of inflammatory factors, inhibits the activity of acetylcholinesterase, reduces the quality of germ cells, and affects embryo development. At last, we speculate that the exposure of microplastics may be related to the formation of various chronic diseases.

https://pubs.acs.org/doi/10.1021/envhealth.3c00052

[brokegrammer]

> Almost all the studies on the toxicity of microplastics use experimental models, and the harm to the human body is still unclear.

You missed this part, which is the most important one.

[therealcamino]

So...perhaps worthy of further study, maybe including to understand where exposure comes from, and whether the particles are absorbed? Like this study.

[zug_zug]

Unclear doesn't mean safe, it just means hard to quantify. Your child could be in a car accident and their survival odds could be unclear, scientifically speaking. Doesn't mean "totally safe."

[lowbloodsugar]

In what way is it the most important one?

Was the most important part of all the tobacco research the bits that said “Smoking tobacco is healthy”? Or the studies of lead in gasoline the caveats that said “These are small samples”?

[homebrewer]

I won't speak for the whole world, but the amount of plastic things around me increased by a couple orders of magnitude in the last 15-20 years. What used to be made of stainless steel, wood or paper is now often made of plastic: tea kettles, dishes, water pipes, food bags, etc. etc. We'll see what effects it has in another 15-20 years when it will be too late to do anything.

[cbdhsjshs]

'Plastic' is a loaded term. It includes lots of different types of platic, as well as intentional (plasticizers) and unintentional (residue in recycled plastic) additives to it. Some of the formulations are fairly new, some have been in use for a long time.

The amount of exposure has also changed. Some bakelite knobs on your armoir aren't a big deal. Sleeping with a 'fleece' blanket and inhaling polypropylene all night every night may not be fine.

Personally, I don't have confidence in being able to be an informed consumer of plastics, and it's easier to just minimize platic use in general without trying to decide what's dangerous and what's ok.

[stackghost]

That's overly simplistic. The negative health effects might be lagging, because when plastic was invented there were zero micro plastics in the environment and now there are lots.

To wit, life expectancies in North America have been declining the last few years.

[dredmorbius]

Post hoc ergo prompter hoc fallacy.

Actually, it's not even that as most of the modern increase in life expectancy / fall in mortality occurred before the invention of plastics.

The former largely concluded by the 1920s. Plastics were largely invented during the 1930s, and were introduced as products over subsequent decades, at an ever-increasing rate.

Which is to say: whatever lead to the increase in life expectancy was largely not plastics. Rather it was increased general hygiene, sanitation, food quality, refrigeration, waste removal, and sewerage systems.

I'd mentioned this only a few months back, note especially my follow-up comment which similarly points out another frequently-touted factor which also fails the temporal sequencing test:

<https://news.ycombinator.com/item?id=41020120>

[hansvm]

Or not bad enough to overcome other benefits that came out around the same time.

[thoroughburro]

“Accumulation” is a keyword you might want to examine.

[Empact]

Just because smoking and exercise made you visibly fitter, doesn’t mean you should disregard the consequences of smoking.

[littlestymaar]

This argument makes no sense, life expectancy increased a lot after the invention of leaded gasoline†, yet nobody would say it's harmless.

[†]: Works as well for high fructose corn syrup or Fentanyl.

[inglor_cz]

But fertility dropped. May be a contributing factor.