Microplastics in the human brain

Sounds like methodological error. Like your black spatulas. Somewhere they’ve divided by zero, clamped, and averaged or something dumb like that.

Nanoplastics can be so small that they can get inside most cells even blood cell so could pass through gut lining and blood brain barrier and sometimes are shaped like the key/lock our body already uses for certain intracellular chemical interactions and interferes with the correct molecules doing work, so they can be both inert for the most part and harmful because our cells just don’t just eject them automatically - though there also appears to be some max amount based on exposure level. The vast majority we might eat is excreted in bowel movements and urine and it still accumulates in tissue due to ubiquity. article for laypeople https://www.npr.org/sections/shots-health-news/2024/12/18/nx...

Government could force car tyre companies to invest in developing plastic free tyre alternatives?

If there's no regulation then there's no will or urgency to waste money doing so.

That is perhaps the most insidious property of all when it comes to microplastics--it's incredibly difficult to work that out.

We don't have control groups, they're found in virtually every complex organism on Earth, including (best we can tell) all humans, so we can't form a control group. We've only recently really started to notice, care, or study them, so we don't have strong historical data to compare against. We don't have many isolated populations (especially of large enough size) where microplastic bioaccumulation is the only major difference in how their lives have changed in biologically relevant ways over the decades, so we can't effectively isolate the effects of microplastics from other confounding factors.

So you have these things that basically became completely ubiquitous--an unavoidable fact of not just human life, but all complex life on Earth--before anyone realized, with several other major global factors shifting concurrently. The end result is that, by the tools and methods with which we perform science, it's nearly impossible to study their exact effects. Maybe they're a slow-burning apocalypse subtly disrupting the mechanisms of life at their most fundamental levels and only getting worse with time, or maybe they do nothing or next to nothing like having a glass of sherry with your Sunday brunch once a week, or maybe they're somewhere in that vast, murky expanse in between the two extremes. Hell, there might even be a net benefit somehow. We just plain don't know, and don't know how we could know, so speculation is just about all we've got at present, and without knowing it's really hard to say if the messaging and literature surrounding the subject is aggressively over-alarmist or recklessly under-alarmist. The best we've really got is the simple fact that we notice them now, and thus have the chance to pay close attention, part of which is regularly taking basic measurements like these to try and correlate trends.

About all we do know is that they weren't here before, and "before" encompasses 99.9999% of all life that we know to have ever existed, so it's definitely weird and maybe probably bad.

There's definitely criticism to be had with the broader state of public health and science communication that harm, or at least the understanding that "we have literally no idea what the broader implications of this are but they're maybe probably not good", are considered to be implicit, either due to fallacious appeal to nature or the simple fact that alarmist headlines catch more attention, generating more traffic and revenue, and thus acceptance rates and grant money downstream. Which is, I think, the real core of the issue.

The weight of the average car is steadily increasing though. SUVs, electrics, giant trucks, etc.