[HN Gopher] Microplastics in the human brain
___________________________________________________________________
Microplastics in the human brain
Author : headclone
Score : 223 points
Date : 2025-02-06 01:13 UTC (21 hours ago)
(HTM) web link (www.smithsonianmag.com)
(TXT) w3m dump (www.smithsonianmag.com)
| bhaney wrote:
| > not a spoonful, but the same weight as a plastic spoon
|
| _oh_
| SecretDreams wrote:
| That's not great
| silisili wrote:
| That's both a misleading headline and a really odd unit of
| measurement. So odd that I wouldn't be surprised if the US
| adopted it as the official unit of measurement of microplastics
| (I kid, as an American).
| ryandrake wrote:
| How many Bald Eagle Per Football Fields would that amount to?
| smnrchrds wrote:
| - There is a horrifying 512-ounce version that they call Child
| size. How is this a Child-sized soda?
|
| - Well, it's roughly the size of a two-year old child, if the
| child were liquefied.
| mindwok wrote:
| I find this hilarious. Why would they choose such a misleading
| unit
| card_zero wrote:
| Isn't it about the same?
|
| How big is a spoon, anyway?
| upghost wrote:
| do we need a unit conversion for how many spoonfuls of plastic
| are in a plastic spoon?? seems like it might be important for
| this article.
|
| Well article says a teaspoon has 7g mass, and just spitballin
| here but I'd say a plastic spoon has about 1g/cm^3 density. And
| there are 4.83cm^3 in a teaspoon. So I guess in fact there are
| 1.44 teaspoons of teaspoon in the brain. Or would that be 1.44
| tsp^2...?
|
| But I'm an American and I have at least 3 imperial teaspoons of
| microplastic in my brain or gosh darnit I'm 2 bald eagles short
| of a touch down. If you know what I'm sayin.[1]
|
| [1]: https://news.ycombinator.com/item?id=42958104
| TZubiri wrote:
| So more
| chiefalchemist wrote:
| As I understand it, they took a small sample of brain tissue,
| extracted the plastic, and then extrapolated that (based on the
| tissue sample size) over the whole of the brain.
|
| This assumes the presence of plastic is evenly distributed
| throughout the brain, which isn't necessarily the case.
| robocat wrote:
| I am hoping that they discover that polyethylene is a natural
| component of brain chemistry.
| jondwillis wrote:
| What about polystyrene, polyvinyl chloride, et. al?
| medellin wrote:
| I would think that we would be seeing a lit more issues if we
| had that much plastic just in our brain. But maybe our body
| doesn't mind all that much. I guess we will see how things play
| out in another 30 years though.
| chiefalchemist wrote:
| Huberman Labs has been mentioning plastics in the body
| frequently.
|
| Don't laugh, but I'm getting a new toothbrush to be safe.
| mythrwy wrote:
| This is one of those headlines that smells like nonsense before
| even reading the article (doesn't mean it is nonsense, but the
| quantity advertised seems implausible).
| megamike wrote:
| just a spoon full of plastic helps the medicine go down the
| medicine go down the......
| koolala wrote:
| I thought it was our gonads that had the most?
| jdiff wrote:
| This statement isn't necessarily at odds with that one.
| shironandonon_ wrote:
| I like the analogy where other articles have said we have
| microplastics in our brain about the size of a credit card (which
| generally weigh between 4g and 10g) better.
|
| Saying a "spoon's worth" seems to be downplaying the unmitigated
| potential risk. We have no idea what will happen as we (and all
| the other creatures on earth) keep storing more and more
| microplastics in our organs.
|
| Nobody is going to stop driving. Car tires are the largest source
| of microplastics.
|
| (actually I don't drive though so who am I to judge)
| roenxi wrote:
| > unmitigated potential risk
|
| The risk does seem fairly mitigated, most of us will make it
| through today fine. The only part of my brain I can account for
| now is the 1x credit card worth of plastic, all the other bits
| are a mystery. Death was inevitable before the microplastics,
| remains inevitable after the microplastics and things seem fine
| so far.
|
| We don't know much about the risks of anything. People
| regularly douse themselves with mind-altering substances and
| ingest the weirdest variety of stuff.
| rTX5CMRXIfFG wrote:
| Shortening your period of observation so that the effects
| have not occurred yet does not mean it's "mitigated".
|
| And your philosophy of your own mortality is just as
| reductive, because humans have been trying to survive since
| time immemorial and do not actively work on their deaths
| unless in an unhealthy mental state.
| card_zero wrote:
| Seems like a more important problem, then, the part where
| people inevitably die. I mean compared to having some
| plastic in their heads.
| johnnyanmac wrote:
| I mean, what are we really going to do about it? So much
| chaos in the world, I don't think many are focusing on
| keeping plastics out of our body. No one's championing it.
| SmirkingRevenge wrote:
| Would be nice if just once these sorts of things could have
| beneficial effects.
| card_zero wrote:
| Like the ship-produced aerosols that seeded clouds,
| increased albedo, and cooled the planet, in what James
| Hansen has called a "Faustian bargain". We successfully
| stopped that with regulations.
| itishappy wrote:
| > The risk does seem fairly mitigated, most of us will make
| it through today fine.
|
| This is an incorrect usage of the word "mitigate." To
| mitigate means to lessen the risk. Mitigation requires
| action.
|
| I suspect you mean that the risks are "overstated."
| roenxi wrote:
| I barely think the risks have been stated at all. They
| found a correlation between high levels of microplastics in
| the brain and dementia. There is a correlation between a
| bunch of things and dementia. I expect there is a
| correlation between good health and dementia, unhealthy
| people would tend to die off young without the time to fall
| apart mentally.
| tcfhgj wrote:
| > Nobody is going to stop driving. Car tires are the largest
| source of microplastics.
|
| many already have, bicycles and public transport ftw
| lenerdenator wrote:
| There's realistically fewer than twenty metro areas in the US
| where the majority of commuters could rely solely on biking
| and public transit for everything. Twenty might be generous,
| even.
| sien wrote:
| Since the pandemic passenger car miles, airline miles are
| back at pre-pandemic levels.
|
| Transit use is at 80% of pre-pandemic levels.
|
| https://ti.org/antiplanner/?p=22722
|
| Farebox recovery ratios have consequently become even
| worse.
|
| The new US government is also presumably not going to fund
| much transit expansion.
|
| It'd be interesting to see if more people work from home on
| a given day than use mass transit to get to work.
|
| It's also pretty similar in Australia at least and probably
| in more places around the world.
| idle_zealot wrote:
| There is a positive spin on this: the majority of Americans
| already live in or near dense urban centers. If we had
| solid public transportation only within these centers and
| to adjacent suburbs we would eliminate most car trips.
| That's bot much physical area to cover.
| lenerdenator wrote:
| Depends on what you consider "in or near".
|
| I live "in" a major American city. Well, a reasonably
| major Midwestern city. It's roughly a third the size of
| Rhode Island. It has half a million people in it.
| raddan wrote:
| That may be true, but you don't have to rely on biking for
| "everything." Some biking is better than no biking.
|
| I live in a small college town a couple of miles from the
| college. I walk, run, or bike to work nearly every day. But
| I am not a purist about it. We have a snowstorm forecast
| for tomorrow so I am going to drive (my EV). Would it be
| better for the environment if I walked? Probably? Does one
| trip really make that much of a difference though? Probably
| not.
|
| I think there are likely many many places where people can
| walk or bike to some of the things if not all of the
| things. People really should do that more (not the least
| reason because biking is wonderful). Biking to the grocery
| store is mostly impractical for me as it is many miles
| away. But that's ok! I am doing other things.
| knowitnone wrote:
| still rubber so still microplastics?
| tcfhgj wrote:
| Less!
| pants2 wrote:
| Unfortunately a bicyclist on the road will be exposed to far
| more tire microplastics than drivers in their enclosed cabins
| with filtered and recirculated air.
| card_zero wrote:
| To me, the spoon sounds scarier. But I don't think there's a
| right answer to how scary a new phenomenon should be made to
| sound. You want it to sound scarier, this thing we don't know
| much about? Won't that happen naturally since everybody's ready
| to be scared of news anyway? Is it being downplayed? Relative
| to what, hunches? The information should be presented
| dispassionately, but engagingly, and that is an impossible
| combination, so it what we'll actually get is always something
| with the wrong overtones.
| wruza wrote:
| Not to mention that all spoons are different. I always get
| confused about "half a spoon". Is it half of a "pile" or there
| must be half of its surface visible from above, while the
| subject matter is flat in the spoon (i.e. the lateral
| projection shows only the spoon). And should you account for
| the pile slope in case of bulk materials? And then when you
| figure that out, your spoon may be anywhere 0.5-1.5x in
| size/depth than someone else's. It may be literally 3x times
| more or less. But even that is still less inexact than
| measurement extrapolation methods that the article uses,
| according to the top commenter.
| plagiarist wrote:
| I was trying to figure out from the headline if they meant
| enough microplastics to fill the bowl of a spoon or
| microplastics equivalent to a plastic spoon. I don't know why
| everyone is allergic to weights and measures.
|
| If they're going for shock value they should use something
| more sinister than a spoon. Like enough plastic to make a
| little decorative Halloween spider. People would be more
| frightened by a spider than a spoonful of plastic.
| adriand wrote:
| The only good news here is that it's possible that the body can
| clear the plastics. This is from the linked study:
|
| > While we suspected that MNPs might accumulate in the body over
| a lifespan, the lack of correlation between total plastics and
| decedent age (P = 0.87 for brain data) does not support this
| (Supplementary Fig. 1). However, total mass concentration of
| plastics in the brains analyzed in this study increased by
| approximately 50% in the past 8 years. Thus, we postulate that
| the exponentially increasing environmental concentrations of
| MNPs2,14 may analogously increase internal maximal
| concentrations. Although there are few studies to draw on yet
| performed in mammals, in zebrafish exposed to constant
| concentrations, nanoplastic uptake increased to a stable plateau
| and cleared after exposure15; however, the maximal internal
| concentrations were increased proportionately with higher
| nanoplastic exposure concentrations. While clearance rates and
| elimination routes of MNPs from the brain remain uncharacterized,
| it is possible that an equilibrium--albeit variable between
| people--might occur between exposure, uptake and clearance, with
| environmental exposure concentrations ultimately determining the
| internal body burden.
|
| Which means that if we were to take action on this, we might
| actually be able to reduce our exposure. Unfortunately, things
| are going in the wrong direction.
|
| I keep thinking it would be nice if microplastic exposure were to
| start generating the kind of focus and controversy that is
| currently taking place with vaccines and autism spectrum
| disorder.
| russdill wrote:
| My understanding is the best thing you can be doing along with
| reducing exposure is regular blood donation
| ericd wrote:
| So what you're saying is that leeches as medicine are coming
| back.
| lemonberry wrote:
| Interesting. My father has received a ton of donor blood over
| the past few years. Once he's gone I'll be donating
| regularly. My father's alive because dozens of people
| donated.
|
| To anyone here that has made a deposit to the blood bank: we
| thank you.
| knowitnone wrote:
| blood bank CEO thanks you too because the make millions
| selling your blood
| Loughla wrote:
| Go away. Just go away. Sometimes too much cynicism is
| toxic.
|
| Donating blood is good for other people regardless of the
| profit motive from the company.
|
| And if you're talking about the Red Cross, their CEO is
| reported to make less than 700k/year.
|
| That's not bad for running one of the largest medical
| non-profits in the world.
| johnnyanmac wrote:
| Cool, what was I gonna do with it? Unless we're selling
| to Dracula, owning external blood is highly regulated. So
| anyone buying has some credentials to use it.
| throwaway657656 wrote:
| dilution is the solution to the pollution
| card_zero wrote:
| Pass the microplastics along to some other sucker, a cunning
| plan.
| TZubiri wrote:
| So bloodletting?
| throwaway657656 wrote:
| >>environmental exposure concentrations ultimately determining
| the internal body burden.
|
| As another commenter asked "How did the amount of brain
| microplastic manage to double between 2016 and 2025?" It is
| doubtful that the environmental concentration level doubled
| during this time.
| mreid wrote:
| I must have some of that microplastic in my brain since I misread
| the start of the title as "Human, Brian May, ..." and then
| couldn't parse the rest properly.
| scotty79 wrote:
| Cool. Now how much sand is in your brain? Equivalent of two glass
| spoons? Sand dust is way more abundant than plastic and similarly
| inert.
| kijin wrote:
| Depends on where the sand is. I don't want that stuff in my
| lungs.
| pulvinar wrote:
| Lungs have been dealing with sand dust since there were
| lungs, have they not?
|
| Honest science on a foreign material in the brain or body
| should be able to present a baseline amount of total foreign
| material for comparison.
|
| If our environment is now 10% microplastics, then 10% of the
| foreign material found in the brain being microplastics would
| be normal.
| drawkward wrote:
| Such an easy point, and yet the parent posters dont get
| it...
| pfdietz wrote:
| Or plant fiber. You eat enormous amounts of this stuff that you
| can't break down.
| crazygringo wrote:
| You're being downvoted, but I think it's a really good
| question.
|
| We eat and breathe all sorts of stuff that comes in nano-sized
| particles. We've been inhaling smoke from cooking fire, eating
| plant matter crushed between rocks rubbing against each other,
| drinking water with dissolved bits of all sorts of things, and
| so forth for many millenia now.
|
| The body seems to have mechanisms to clear most of this stuff
| out of us over time, no? Isn't our body chock-full of waste
| products from our cells that are constantly getting flushed
| out? Is there any reason to think that nanoplastics would be
| different?
| Kapura wrote:
| Remember that car tire degredation is a significant portion of
| microplastics in the environment. Investing in mass transit is as
| imperative as it was to move away from leaded gasoline.
| mythrwy wrote:
| Move away from big cities and high traffic areas in the
| meantime is my solution.
| dymk wrote:
| Hope you never have to drive to the grocery store
| forgetfreeman wrote:
| Hope you never have to haul a family of 4 worth of
| groceries on a bus.
| dashundchen wrote:
| I do on a bike or walking weekly, it's not that crazy.
|
| In a prewar US mid sized city, the density supports
| multiple grocery stores I can reach in about the same
| time as driving and finding parking.
| forgetfreeman wrote:
| Groceries. For a family of four (4). On a bicycle. Sure.
| How many times a day do you make the trip?
| andrewshadura wrote:
| What's so crazy about that? Never seen a bicycle with
| panniers and a basket? Or a cargo bicycle?
| forgetfreeman wrote:
| I've seen what a week's worth of groceries looks like for
| four people and short of a rickshaw you ain't getting all
| of that on a bicycle with or without panniers. I'm fairly
| certain the respondent is coyly ignoring the headcount
| requirement in my original sneer.
| dashundchen wrote:
| I make at least trip one trip a week. Why would I need to
| go every day?
|
| I may stop by a store again during the week for a smaller
| trip if there's something I really need, or pop to a
| corner store if I need to grab something like drinks for
| guests, but it's not out of my way.
|
| It's really not a big deal. Bike panniers can hold a ton.
| hombre_fatal wrote:
| Trivial if you leave near a grocery store. If you live in
| most US cities, much more the suburbs, then being
| dependent on your vehicle to do literally anything is
| part of the problem. In very few places in the US can you
| choose to do otherwise.
| mc3301 wrote:
| 15 minute cities is the answer.
| bilbo0s wrote:
| Not only that, but if you're close to a road at all, you'll
| intake the micro-plastics and nano-plastics.
|
| So you really need to move away from roads. That's
| possible, but it's really hard to do in most developed
| nations. Just moving away from a city won't get you to
| where you need to be. Even when you get there, you have
| other issues. Like, food, energy, water/sewage treatment,
| etc.
|
| I don't think people realize how difficult it would be to
| get away from this particular pollutant in our environment.
| I mean most of us don't own 500 acres in the Brazilian,
| Namibian, or Ghanaian countryside that we can retreat to.
| Even Brazil may be too far gone at this point to be honest.
| And Brazil is enormous. A lot of space. The number of
| tolerable nations that would have unaffected areas is
| decreasing fast. This really is a global problem.
|
| ETA: Some remote parts of Canada and Alaska might fit the
| bill? Assuming you're not big on quality of life.
| idiotsecant wrote:
| You can have really very good quality of life in remote
| areas. You just might die before you get help if you have
| a heart attack or something. But the rest of the time
| it's great!
| mythrwy wrote:
| I don't think you understand where I'm living.
|
| "Microplastic Free", no, there is no such thing right now.
| But I'm very far from any major roads/interstates and
| hundreds of miles to any big city. I didn't move out here
| to avoid microplastics though, it just (maybe) turned out
| that way.
|
| I'm actually not terribly afraid of microplastics at all, I
| just don't like urban environments.
| epistasis wrote:
| Imagine a grocery store that is within a short walking
| distance, such that you don't need to haul a weeks worth of
| groceries but can get fresh food every single day.
|
| US supermarkets are massive, take forever to buy small
| amounts of groceries, and even the walk to and from the car
| is long.
|
| A better world is possible! (If better grocery stores
| constitute a "better world")
| bluefirebrand wrote:
| > you don't need to haul a weeks worth of groceries but
| can get fresh food every single day
|
| I lived that life in my 20s
|
| Turns out I don't actually want to go to the grocery
| store every day. I want to go once a week and stock up,
| which I can do thanks to inventions like the refrigerator
| and the automobile
| lurking_swe wrote:
| no judgment on you in particular, but i'm not a fan of
| this thought process. I believe it's a major cause for
| why americans (statistically) are so obese. and i say
| this as an american that lives in a city but has family
| in the suburbs.
|
| running errands with your own two feet every day by
| walking, cycling, etc keeps people healthy and lean. this
| country has a major car problem. it's sad.
|
| of course one can go to the gym to stay lean and healthy,
| but that's even more time consuming than stopping by the
| store for 5 minutes on the way home, and it requires
| extreme motivation. Hardly an improvement i'd say.
| imp0cat wrote:
| one can go to the gym
|
| And by that you mean drive to the gym, right? ;)
| bluefirebrand wrote:
| > running errands with your own two feet every day by
| walking, cycling, etc keeps people healthy and lean. this
| country has a major car problem
|
| I did live this exact lifestyle in my 20s. I was
| definitely more active but my diet was way worse. I was
| closer to a lot of restaurants, and I was closer to a lot
| of bakeries and convenience stores and such as well.
|
| A healthy lifestyle also requires a healthy diet and city
| living gave me far too much easy access to snacks and
| junk food. A lot of "it's only 5 minutes to go buy a
| snack". Daily stops for coffee that often included a
| pasty
|
| Yeah, the walkable city does mean people are more active
|
| It doesn't necessarily mean they are much more healthy.
| It still requires other forms of self control (which I
| admit, I struggled with)
| globular-toast wrote:
| I don't believe it. If you lived right next door to the
| grocery shop would you still only go once a week and
| stock up?
|
| Nobody wants less flexibility, rigid plans and higher
| maintenance costs. I think what you really want is a big
| house with lots of space away from other people and since
| you can't have your cake and eat it too you've sacrificed
| everything else.
| bluefirebrand wrote:
| You got me
|
| I actually did live in an apartment a block away from a
| grocery store and yes, you're right. I would not trade my
| current house for having a grocery store that close
|
| Because living in apartments sucks
|
| But even if I did live in my current house with a grocery
| store right next door, I still would prefer to go as few
| times a week as possible. Planning ahead and limiting how
| often I am at stores helps me tremendously with sticking
| to a budget, which is also something I place a lot of
| value on
|
| When I lived close to a grocery store not only did I
| spend more because the prices were higher, I also made
| more frequent trips for things on a whim, like snacks and
| treats. It was a much more expensive lifestyle
|
| Maybe other people don't have that same struggle with
| convenience, but I do. By making the barrier higher, my
| life is more affordable and I eat less junk food for sure
|
| This is all just my experience though
| epistasis wrote:
| Well good news, nothing is stoping you from bringing home
| a full cartful of groceries that walking distance either.
| You just have more options.
|
| Now, if you are really attached to your car and are only
| open to using your car for groceries, stay in suburbia,
| it's oversupplied through centralized planning and not at
| risk of going anywhere!
| bluefirebrand wrote:
| > Well good news, nothing is stoping you from bringing
| home a full cartful of groceries that walking distance
| either
|
| Dunno about you but I only have two hands and can only
| carry so much at one time
|
| I could have bought and brought a wagon or something I
| suppose, but that presents its own problems.
|
| Where do I store the wagon in my tiny apartment?
|
| What do I do with it when I'm actually in the store
| shopping, to make sure no one steals it while I'm in the
| store? I can't bring it into the store, it's too bulky
| for narrow urban grocery store aisles
|
| How do I get my wagon full of groceries to my apartment,
| with no elevator?
|
| Actually how do I get my empty wagon up to my apartment
| even, it's not going to manage narrow stairwells very
| easily even empty. So even if I leave it at the bottom
| and carry my groceries up by hand, I still have to get
| the wagon itself upstairs somehow
|
| And then I also own a wagon that takes up my limited
| apartment space, which I only use to get groceries and
| provides no other utility for my life.
|
| Unlike a car which I use all the time and only one of
| those uses is getting groceries
| ergl wrote:
| Have you never heard of a shopping caddy?
| https://en.wikipedia.org/wiki/Shopping_caddy
|
| They're incredibly popular here, and yes, all
| supermarkets will have a lock stand near the checkout
| area so you can leave them there and easily reach for
| them as you're bagging your groceries. They're also
| foldable and/or small enough to fit in almost any closet.
| nozzlegear wrote:
| My grocery store is literally in another town 20 miles
| away. I have an EV but apparently those are even worse for
| microplastic generation. Am I screwed?
| raddan wrote:
| An EV is objectively not worse for the environment. And
| virtually all vehicles contain large amounts of plastic
| (eg PVC). I recently heard model year 2024 vehicles are
| ~30% plastic by weight.
|
| I'd wait until somebody can clearly state what the
| demonstrated harms of microplastics are before you
| conclude that there's nothing you can do. An EV reduces
| emissions that we KNOW are bad, and over their lifetimes,
| the reduction is huge compared to an ICE vehicle. If
| you're worried, though, walk or bike whenever you can.
|
| Biking to grocery store is not an option for you, but you
| can still make a difference if you think about it. Eg, go
| to the store less frequently. Switch to a chest freezer
| for perishables. And so on. Draw up an energy budget and
| do the math.
|
| There is a cost to human life, sure. But you can make it
| work if you really care enough. You are definitely not
| screwed.
| shironandonon_ wrote:
| Doesn't work. It's in the rainwater. No rainwater on earth is
| safe to drink.
|
| https://www.bbc.com/news/science-environment-62391069
| mythrwy wrote:
| Does osmosis remove? Is it in all groundwater?
|
| Because I have a well. A deep one. And an osmosis system.
| idiotsecant wrote:
| Do you consume drinks? Meat? Produce? All these things
| are chock full of their own micro plastics. It's
| unavoidable. We can probably reduce contamination but our
| children's children's children won't be free of it, not
| until organisms evolve to efficiently eat it. Then we'll
| have whole other sets of problems.
| mythrwy wrote:
| Do I consume drinks? No, except water and instant coffee,
| no soda, no beer. Meat? Yes in small quantities and much
| of it comes from the local environment. I grow most of my
| own produce, with RO water.
|
| Yes they are unavoidable, just the plastic containers etc
| probably give some and I do eat candies and imported
| bananas and bread etc. But pretty sure I get a lot lower
| dose than most people.
|
| However I'm not sure it matters that much until a
| mechanism of actual damage is established.
| raddan wrote:
| > However I'm not sure it matters that much until a
| mechanism of actual damage is established.
|
| This is the thing about all the microplastics articles I
| see popping up: they rarely include any description of
| harm. If they even mention it, it is only speculative, as
| in this article. Until I read a scientific article about
| real harms, I am going to regard most of the
| microplastics news as fearmongering. Humanity has been
| surrounded by vast quantities of plastic for decades; if
| there was a big effect, wouldn't we have seen it by now?
| If it has big effects, those effects would be surprising,
| which means that the evidence would have to be strong. I
| don't see a lot of strong evidence.
|
| If anyone reading this has a paper like this, please
| share.
| albertsondev wrote:
| 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.
| mrguyorama wrote:
| There is no strong evidence of anything yet, but consider
| how long it took to "prove" to society's satisfaction
| that cigarettes are harmful, despite most scientists
| finding the lung cancer connection quite clear from
| pretty early. Comprehensive and long term data takes a
| long time. It could be worth it to be cautious in the
| meantime.
|
| If microplastics are making our lives 10% worse in some
| dimension, we will have to stumble onto what that
| dimension would be basically by luck and then spend at
| least a decade rigorously studying it before we could
| make useful assertions.
|
| The hubub about microplastics is that, we don't have
| great civilization wide health data on most health
| dimensions, so we don't even have good baselines to
| figure whether we have regressed in many ways. IF there
| is a negative effect, _it will effect everyone all over
| the planet and there is no escape_
|
| It's an extreme corner of the likelihood/amount of harm
| graph, and some people think that corner of the graph
| warrants caution even before harm is proven.
|
| It's the same situation we faced with leaded gasoline,
| and the US is pretty bad when it comes to those kinds of
| "mild, diffuse harm that mostly affects people who can't
| afford whatever system the wealthy use to avoid the harm"
| problems.
|
| It's not fearmongering, we are literally gambling that
| microplastics have minimal harm right now.
| UniverseHacker wrote:
| > I grow most of my own produce, with RO water
|
| Do you really grow enough food to make up most of your
| diet on RO water? And is this specifically to avoid
| microplastic exposure, or what?
| mythrwy wrote:
| I grow around 1/3 of my own food. Yes all with RO water.
| I'd like to get above 50%.
|
| Specifically produce, however we grow most of what we
| eat. We pressure can, dehydrate and ferment to preserve.
| I have background and decades of experience in growing,
| which is to say it's more than just standard hobby garden
| level.
|
| The RO water is not to avoid microplastics (although that
| might a side benefit) but rather that the water is highly
| mineralized. It would be a long post to explain why I do
| this. Some is theoretical health concerns, some is more
| practical.
| timeon wrote:
| This is really interesting. Do you have suggestions how
| to use RO in garden scale? (Like link where could I
| start)
| mythrwy wrote:
| I built my own RO system it cost around $1500 including a
| water softener. There are some ongoing supplies every
| year, maybe $200 or less.
|
| I don't have any links I just figured it out, but it's
| not super complicated. I made it out of undersink RO
| membrane housings (housings from those little RO systems
| you can buy for around $300 that do a couple of gallons a
| day). The membranes have pressure pumps in front of them
| that get it up to a couple hundred gallons RO water total
| a day.
|
| Basic steps are 1) Soften the water, 2) Pass it through
| very tight filters (like 1 micron), I also carbon filter
| for organic contaminants, 3) Booster pumps put water
| through osmosis membranes and from there into a storage
| tank.
|
| I just used plastic totes with gravel in the bottom to
| house the membranes and booster pumps.
|
| I should write up a blog post on it one day because
| professionally installed osmosis can be expensive.
| timeon wrote:
| Thanks!
| UniverseHacker wrote:
| Interesting, thanks!
| card_zero wrote:
| I guess the polyamide filter in that system isn't putting
| microplastic particles in the water? Probably not.
| tocs3 wrote:
| 6 months ago on HN "Boiling and filtering can remove
| microplastics from drinking water: study:
|
| https://news.ycombinator.com/item?id=41193531
| sebmellen wrote:
| Nanofiltration or reverse osmosis will be most effective:
| https://www.epa.gov/sciencematters/reducing-pfas-
| drinking-wa... (save the site while the EPA still
| exists!)
| hammock wrote:
| And we need more lightweight cars , not heavier, since tire
| wear is proportional to vehicle weight to the fourth power.
| Ironically, CAFE regulations and EV incentives both did the
| opposite
| kijin wrote:
| > tire wear is proportional to vehicle weight to the fourth
| power.
|
| Does this mean that a bus that weighs 10 times as much as a
| small car will produce 10000 times as much tire dust? If it
| does, I'm not sure if investing in buses will reduce tire
| dust at all. A bus can replace a lot of cars, but 10000 is a
| stretch. We need more trains.
| penjelly wrote:
| trams were popular in tons of places before, I understand
| they improved traffic significantly compared even to today,
| and they'd still have a positive effect now, I think. But
| most places shifted towards a car centric focus and we lost
| those.
| zamadatix wrote:
| I think the root observation here comes from
| https://en.wikipedia.org/wiki/Fourth_power_law which really
| talks about the inferred stress to the road for given
| weight on the axle, not tire wear based on vehicle weight.
| The above seems to be using a simplification based on
| passenger cars staying with 4 tires across 2 axles but how
| this relates to tire wear is going to be a bit more
| complicated when you start talking about vehicles which can
| have more axles, more tires per axle, and significantly
| larger tires.
|
| I'd believe buses have a lot of tire wear compared to an
| individual car but I wouldn't use that relation as proof of
| just how many times so.
| ethagnawl wrote:
| I'm not sure why you're being down voted for suggesting a
| practical and fact based solution. The USA is, regrettably,
| not making a pivot towards public transportation anytime in
| the near future. So, lighter cars are one way to address this
| issue.
|
| You didn't expound upon your point about the unintended
| consequences of CAFE standards but they're very real. Instead
| of making smaller and more efficient sedans per the
| guidelines, car makers opted start making all of their
| vehicles "light trucks" -- 80%+ of new vehicles are SUVs or
| bubbly looking "crossovers" -- which are not subject to the
| same demanding standards. Small sedans also cost less and
| would require ongoing R&D to continue to meet the CAFE
| standards. The end result, as this thread is interested, is
| heavier vehicles with bigger tires and more plastic in the
| environment and our brains.
| linotype wrote:
| Los Angeles would be very difficult to transition at this
| point, it's just too low density. It was better 100 years
| ago than it is now.
| lenerdenator wrote:
| Or Kansas City. Or St. Louis. Or Detroit. Or Chicago,
| even.
|
| Pretty much any major American city is less dense than it
| was 100 years ago. It was cheaper to build out than it
| was to build up.
| wongarsu wrote:
| From an infrastructure perspective building out instead
| of up is incredibly expensive. Not just transport but
| also water, sewage, electricity and internet.
| lenerdenator wrote:
| I should specify: it's more expensive _for the developers
| and their home-buying customers_ to build up instead of
| out.
|
| All of that stuff you listed comes from tax dollars, and
| people ultimately care less about that than what's coming
| out of their pockets for a home purchase. Well, until
| it's unsustainable, anyways.
| tstrimple wrote:
| Yes exactly. Building is cheap in the US relatively
| speaking. There are tons of grants and government money
| to help move things along. Those avenues don't really
| exist for _maintaining_ things that were built with
| grants and outside funds. So we see TONS of expansion
| followed up with almost no maintenance and suburbs and
| less populated places literally cannot afford to maintain
| the services that they utilize. The burden is almost
| entirely shifted onto renters in urban areas instead.
|
| In this country we have this ideal of a rugged
| individualist whose out there living off the land and
| making his own way. Never will this rugged individualist
| acknowledge that he's dependent on 10x as many miles of
| roads as his urban counterpart. Never will this rugged
| individualist acknowledge that providing him with
| internet access on the state's dollar costs orders of
| magnitude more than someone living in a sustainable
| location. Same with delivery costs and literally every
| other thing this person consumes. They get to pretend to
| be a self-reliant individualist while leaching off of the
| tax dollars of urban residents who cost a fraction of the
| amount to support.
| robertlagrant wrote:
| > Never will this rugged individualist acknowledge that
| providing him with internet access on the state's dollar
| costs orders of magnitude more than someone living in a
| sustainable location
|
| Thankfully we have Starlink to replace pork consumption
| with actual services.
| peterbecich wrote:
| I find it interesting that at a certain time in Los
| Angeles, a segment of society could afford a craftsman
| cottage house, but not afford an automobile. This was the
| prime era of the Pacific Electric streetcar suburb, say
| around 1890-1920. Today, obviously, anyone who can afford
| a house anywhere in the country can afford an automobile.
|
| The end of the Pacific Electric system was not a
| conspiracy theory by tire companies or anything like
| that; the price of the cars dropped and that's what
| consumers preferred, i.m.o.
| newsclues wrote:
| Fires can solve that.
| lmm wrote:
| Los Angeles is one of few US cities that is managing to
| build at least some new transit lines. Increasing density
| in desirable cities is actually pretty easy, all you have
| to is make it legal (by-right zoning) and then the market
| will do the immensely productive and profitable thing.
| borski wrote:
| You're right, but the thing that leads us to lighter EVs is
| solid state batteries.
| cosmic_cheese wrote:
| Yeah, I'd expect EVs to get lighter over time as
| technology progresses. Car bloat is a much bigger
| problem. Totally insane that little practical city cars
| like the Honda Fit have gone practically extinct in the
| US in favor of bigger, heavier cars that don't even
| necessarily bring improved cargo capacity for all that
| extra bulk.
| ethagnawl wrote:
| I have a 2018 Fit and it's a fantastic car. It gets 36
| MPG and has much more interior space than it would seem.
| I've had taller people ride in it comfortably and its
| crowning achievement was fitting a hot water heater in
| the cargo area with the rear seat split -- without having
| to remove the child car seat on the other side. Pair a
| roof rack and you _really_ don 't need more -- especially
| day-to-day.
|
| It's a crying shame that they've stopped selling them in
| the US. Marketing (the real men need their Rams, thank
| you very much!) and the CAFE loophole seem to have won
| the day, though, and we're all worse off for it.
| njarboe wrote:
| Marketing does seem to work, especially over generations.
| I think the main reason trucks/SUVs were marketed so much
| was because of a 25% tax on imported light trucks and not
| cars. The so called "chicken tax"[1] was imposed on light
| trucks in 1964 and is still with us today.
|
| [1] https://en.wikipedia.org/wiki/Chicken_tax
| mrguyorama wrote:
| A big reason car companies push trucks so much is that
| they are more profitable per unit. Demand is extremely
| limited in terms of quantity, because you can only really
| sell about 1-2 cars per family, per about 10 years.
|
| That means, all else being equal, a car company makes
| more profit selling a vehicle that has a higher profit
| margin. The $80k trucks my family members buy do not cost
| 3X as much to manufacture as say, a nice Camry, but the
| price you pay is about 3X. This means the
| dealer/manufacturer just outright make more money if a
| higher percentage of people buy trucks instead of small
| cars.
|
| Consumers have "signaled" that they will be fine paying
| three times as much for the same exact feature set (no,
| they are not hauling anything, and there certainly isn't
| a massively higher percentage of Americans doing truck
| things than 50 years ago), even using longer term loans
| to make it happen.
|
| When the car market has been basically saturated for
| decades, how else do you "make line go up" than selling
| the same product (transportation) for more money?
| ethagnawl wrote:
| > The $80k trucks my family members buy do not cost 3X as
| much to manufacture as say, a nice Camry, but the price
| you pay is about 3X.
|
| > ... even using longer term loans to make it happen.
|
| I don't understand how so many people are driving these
| vehicles. Not only are they 2-3x as expensive to buy or
| lease but they're also 2-3x more expensive to fuel and
| maintain. (Probably to insure, too?) I don't have any
| data to back this up but my intuition tells me that these
| vehicles and their loans could be the cause of the next
| subprime mortgage-esque financial crisis.
| cosmic_cheese wrote:
| It really is difficult to imagine a better vehicle for
| suburb/city usage than the Fit, unless you have a bunch
| of kids/people to move in which case I'd skip
| crossovers/SUVs entirely and go straight to minivans
| (which are also better than SUVs for most peoples'
| needs).
| penjelly wrote:
| EV/hybrid only "zones" in Europe are crazy to me because the
| electric cars leech more tire carbon into the air anyway.
| Some regulation seems intelligent on the surface, but the
| devil is in the details.
| hatthew wrote:
| Solid/particulate pollution from tires is definitely a
| problem, but in terms of carbon specifically isn't it many
| orders of magnitude less than the carbon from gas engines
| or electric power plants?
| penjelly wrote:
| > These particles can include synthetic rubber, plastics,
| carbon black, and trace metals (like zinc)
|
| you're correct. I mistakenly thought it was only carbon
| coming off the tires. So yeah, EVs have a significantly
| lower carbon output that ICE vehicles. My point still
| stands but thanks for the callout.
| dashundchen wrote:
| EV/hybrids also have regenerative brakes so emit less brake
| dust. Between emissions, tires, and brakes I'd be curious
| to see how it balances out.
|
| But really cycling and transit are the way to go to make
| cities more liveable. Personal cars take too much space in
| a city and ruin the built environment for everyone not in
| one.
| DoingIsLearning wrote:
| Excessive NO2 emissions spewed by diesel engines not
| meeting regulations very literally removed years from our
| collective life spans in city centres across the world.
|
| Despite their own health hazards no amount of tire
| particulate from EV's can achieve that level of widespread
| public health impact.
| audunw wrote:
| These zones are generally densely populated areas, and in
| Europe they usually have low speed limits, and roads design
| to encourage driving at low speeds.
|
| To think that the minuscule difference in tire dust is
| significant at all, compared to the pollutants that EVs
| completely eliminates, is absolutely ridiculous.
|
| The devil is in the details, yes. Have you considered that
| the policy makers have actually looked into the details?
| Have you looked into the details? Have you read any
| detailed reports about tire wear or did you just make up a
| problem based on your own intuition? Because I've seen
| reports from EV fleet operators that indicate that they see
| no difference in tire wear. Most likely the added weight
| (which isn't all that much for modern, smaller EVs.. you
| know, the ones that people actually drive in urban/suburban
| areas in Europe) as a factor is drowned by other larger
| factors.
|
| And we're not that far away from EVs with the same or lower
| weight than their ICE counterparts, so getting these kinds
| of policies in place has some forward-looking aspects to
| them as well.
| joseangel_sc wrote:
| I don't think this is entirely true but we need more research
| https://youtu.be/FcnuaM-xdHw?si=6bvFQdUjHi28CugV
| repiret wrote:
| Do you have a citation for the vehicle weight to the fourth
| figure? There is about a 2X variation in the weight of the
| vehicles I've owned, but even accounting for differences in
| tire size, I can't come up with a 16x difference in how often
| I change the tires.
|
| Thinking about it a different way, there isn't much
| difference in recommended tire pressure among the autos I've
| owned. That means that the pressure between the road and the
| tire is relatively constant but the surface area of contact
| is directly proportional to vehicle weight. For a fixed
| contact pressure, I am struggling to imagine a physical
| process by which the rubber loss is not proportional to the
| contact area.
| darkmighty wrote:
| I know this figure comes from road wear. I don't know if it
| applies to tire wear, and indeed I suspect it doesn't, if
| only because tires tend to scale with vehicle weight as you
| mentioned. I think road wear may be associated with
| structural cracking of the road which may not change
| significantly with tire area.
| daemonologist wrote:
| The fourth power law is usually applied to deformation of
| asphalt roadways (here's a citation for that:
| https://www.researchgate.net/profile/Maxwell-
| Lay/publication...); I haven't heard it applied to tires
| before. If I had to guess I'd agree with you - I would
| expect a smaller exponent, particularly if the tires are
| designed for the given load.
| kirubakaran wrote:
| https://en.wikipedia.org/wiki/Fourth_power_law
| repiret wrote:
| That says nothing about tire wear.
| Etheryte wrote:
| Most studies I've seen on this topic agree that the amount
| of pollution created is not linear, and this also makes
| intuitive sense. The heavier your vehicle, the wider and/or
| larger diameter your tires need to be to give it the
| required amount of grip. If those bigger tires wear out in
| the same time as your smaller vehicle tires, you've already
| created considerably more pollution.
| enragedcacti wrote:
| This Engineering Explained video seems pretty thorough. The
| short of it is that your intuition is in the right
| direction, its definitely not to the fourth power of
| weight. Vehicle weight does contribute to wear but
| according to Continental its less important than driving
| style and road curviness.
|
| https://www.youtube.com/watch?v=hvIcVmSzSEg
| twelvechairs wrote:
| Roads and road standards are a tragedy of the commons. People
| keep buying bigger cars and demanding more, wider lanes and
| parking spaces because they don't take any of the burden
| individually - it's the taxpayers as a whole that foot the
| bill.
|
| Paradoxically most of the 'small government' types are often
| the biggest road users.
| sooheon wrote:
| The solution to tragedies of the commons is to internalize
| externalities. Tax should scale with carbon use, congestion
| contribution, and microplastic emission.
| robertlagrant wrote:
| > Paradoxically most of the 'small government' types are
| often the biggest road users.
|
| I think it's "limited government". I'm pretty sure they
| would prefer roads get more spending.
| guelo wrote:
| None of these things are going to happen. Voters keep voting
| with their votes and their wallets that they want bigger cars
| and don't care about climate change. Meanwhile reactionary
| billionaires have hijacked most of our mass media as we blow
| by the 1.5degC Paris agreement and Trump dismantles our
| science institutions.
| Lanolderen wrote:
| Also motorcycles/scooters. Unless you have children or live
| in a place with serious snow a motorcycle and a car sharing
| app/rentals for when you need to haul a sofa or something is
| a great combo.
|
| Cheap, easy maintenance, good fuel economy and speed, traffic
| jam immunity..
| throwaway81523 wrote:
| How did the amount of brain microplastic manage to double
| between 2016 and 2025? The amount of cars hasn't changed that
| much.
| JKCalhoun wrote:
| User hammock, in this thread, may have suggested an answer.
| markerz wrote:
| Perhaps you're thinking our body is at equilibrium with the
| amount of plastic in our environment, but the reality may be
| that our body accumulates microplastics from the environment
| and they become concentrated over time. Kind of like how we
| can't get rid of heavy metals from our body, so eating lots
| of fish accumulates mercury to toxic levels. But eating fish
| is a conscious decision whereas microplastic exposure is an
| unavoidable fact of life now.
| njarboe wrote:
| You can probably reduce microplastic consumption, but it is
| quite a pain and more expensive. Try buying everything at
| the store not wrapped/bottled in plastic. This does not
| even work as well as you might think as many things are
| wrapped in plastic and then presented as if they were not.
| For example, breakfast sausages in the meat display at my
| local Whole Foods are wrapped in paper when they give it to
| you, but come to the store in ~1lb plastic wrapped
| packages.
| meindnoch wrote:
| The weight of the average car is steadily increasing though.
| SUVs, electrics, giant trucks, etc.
| o_nate wrote:
| Perhaps the proportion of synthetic rubber (vs natural
| rubber) is increasing in tires?
| newsclues wrote:
| I love breathing brake dust too!
| 7e wrote:
| Or one could just mandate that tires contain only biodegradable
| ingredients. That seems an inevitable step since wheel isn't
| going away no matter what the level of public transportation
| is. Some public transit, like busses and some subways, use
| rubber tires today.
| 7e wrote:
| Downvotes for suggesting biodegradable tires. What a site of
| wankers we have here.
| CommanderData wrote:
| 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.
| meindnoch wrote:
| Mass _rail_ transit.
| Kapura wrote:
| Didn't want to come off as too foamer ;)
| niceice wrote:
| What percentage is that?
| timr wrote:
| This paper came up as a pre-print. You can't make the
| extrapolation that the headline is making - they're using gas
| chromatography to estimate quantities from 1-2mg samples, and
| then extrapolating to get to these scary sounding whole-organ
| estimates. If you look at the paper [1], you'll see that the
| microplastics in _in situ_ samples are not discernible by light
| microscopy, and that there was a ~25% variation in _within
| sample_ measurement of the GC [2], indicating a great deal of
| uncertainty in the precision of the fundamental measurement (the
| authors brush this off; see quote below).
|
| Basically, you've got an extremely sensitive measurement system
| being used to make tiny measurements, and then they extrapolate
| these measurements by a huge factor to get to ug/g estimates.
| Further extrapolating (to the weight of an organ, say) when you
| know that there's 25% inter-sample variation, is just guaranteed
| to be nonsense.
|
| [1] https://www.nature.com/articles/s41591-024-03453-1
|
| [2] _" Both analytical laboratories (UNM and OSU) observed a ~25%
| within-sample coefficient of variation, which does not alter the
| conclusions regarding temporal trends or accumulation in brains
| relative to other tissues, given the magnitude of those
| effects."_
| rthomas6 wrote:
| Well, it still tells us something. What are the upper and lower
| bounds of whole brain microplastic content, given that 25%
| variation?
| timr wrote:
| I couldn't begin to tell you [1]. It's not a 25% variation,
| once you've extrapolated from the samples by 10,000x (or
| whatever). The 25% inter-sample error was on a few replicas
| of teeny tiny measurements. The post-extrapolation error bars
| are so wide that they're meaningless.
|
| The Smithsonian magazine article is garbage. Ignore it. The
| paper is saying that they see _longitudinal trends_ in
| plastic bioaccumulation in various cadaver tissues, and this
| is plausible. But no, you don 't have a plastic spoon in your
| head. That's just panic porn.
|
| [1] Actually...I just asked Gemini and it reminded me that
| the expected variance of a draw from a distribution, scaled
| by factor C, should have a variance of _the scaled sample
| distribution_ that grows with C^2. So, if we scale up the
| measurement by a factor of 10,000, we 'd expect the variance
| of the scaled estimate to be proportional to 10,000^2.
| drawkward wrote:
| Why yes, i think i will believe the random internet
| commenter.
| LoganDark wrote:
| Practically every internet commenter is random.
| drawkward wrote:
| Which is fine in plenty of contexts. Rebutting this
| particular article? Nah.
| robertlagrant wrote:
| Evaluate things based on reasoning, not source.
| drawkward wrote:
| Evaluate based on both. Why remove any explanatory
| variables?
|
| And for what it is worth, the paper itself has plenty of
| other interesting findings that OP fails to discuss or
| rebut at all. OP asks an LLM some very basic statistics
| questions, putting into question their ability to
| credibly apply and interpret the LLM's findings.
|
| My interpretation of _that_ evidence is that OP, a random
| internet commenter, just doesn 't think it is credible
| that plastics are harmful to humans, and is grasping at
| plastic straws with cherry picked evidence and poor
| rebuttals to reach that "fact based" conclusion.
| edouard-harris wrote:
| I may be misunderstanding you, but it sounds like you're
| claiming that they had e.g. 10 tiny samples of tissue, that
| their measurements had an average 25% variation across
| those 10 samples, and that therefore the whole brain
| estimate (mass 10,000x that of a single sample) therefore
| has a much greater uncertainty. But doesn't the standard
| error of the mean get _reduced_ by the square root of the
| number of samples? i.e. if you had 10 samples with 25%
| variation across samples, and you 're taking their mean,
| the error of that mean should be 25% / sqrt(10) = 8%. And
| that should be the relative error for the scaled up whole-
| brain microplastic concentration as well. Or is there some
| other source of variation that I'm missing?
| timr wrote:
| You're talking about reduction in statistical variance
| due to replication of measurement (and then averaging).
| I'm talking about what happens when they _extrapolate
| from that value_ by a huge factor (which is what they 've
| done, and the silly article does egregiously).
|
| The paper isn't clear what they mean when they said "~25%
| within-sample coefficient of variation", so I can't
| directly address what you're asking, but it's tangential
| to the point I'm making. My naive interpretation is that
| they did an ANOVA, and reported the within-group
| variance, or something similar.
|
| All I'm saying in my footnote is that, whatever the final
| point estimate, scaling it by a factor of C will affect
| the variance of the final sample distribution by C^2. So
| for example, if you have an 8% variance on the
| measurement at ug/g, and you scale it by 1300 (for 1300g;
| what the interwebs tells me is the mass of a standard
| human brain), then you'd expect the variance of the
| scaled measurement to be 1300^2 * 8%.
|
| That makes a ton of assumptions that probably don't hold
| in practice -- and I expect the real error to be larger
| -- but illustrates the point.
| myrmidon wrote:
| I think there is some kind of mixup, you can not scale up
| the variance _percentages_ quadratically:
|
| If you do a small-scale measurement, say you get result
| of 5g, with a standard deviation of 0.2g. That means the
| variance is 0.04 g^2.
|
| If you then scale the setup up by 1000 (=> getting 5kg as
| expected value), then the variance scales to 1000^2 *
| 0.04 = 40000 g^2.
|
| BUT the standard deviation is still 200g. The relative
| uncertainty is NOT increasing quadratically!
|
| (another sanity check: if you change the units by a
| factor of 1000, your variance must not increase,
| relatively).
|
| But maybe I misunderstood your point?
| timr wrote:
| > If you then scale the setup up by 1000 (=> getting 5kg
| as expected value), then the variance scales to 1000^2 *
| 0.04 = 40000 g^2.
|
| They didn't "scale the setup". They made a small-scale
| measurement, then extrapolated from that result by many
| orders of magnitude. They didn't grind up whole brains
| and measure the plastic content.
|
| Imagine the experiment as a draw from a normal
| distribution (the distribution is irrelevant; it's just
| easier to visualize). You then multiply that sample by
| 10,000. What is the variance of the resulting sample
| distribution?
| myrmidon wrote:
| > What is the variance of the resulting sample
| distribution?
|
| Relatively? The same. Yes it scales quadratically, but
| that is just because variance has such a weird unit.
|
| Just consider standard deviation (which has the same
| physical unit as what you are measuring, and can be
| substituted for variance conceptually): This increases
| linearly when you scale up the sample.
|
| An example: Say you take 20 blood samples (5 ml), and
| find that they contain 4.5 ml water, with a standard
| deviation of 0.1 ml over your samples.
|
| From that, your best guess for the whole human (5 liters,
| i.e. x1000) has to be 4.5 liters water, with standard
| deviation scaled up to 0.1 liters (or what would you
| argue for, and why?)
| drawkward wrote:
| ...so you are saying that the probability distribution
| indicates that there is a 50% probability that there _more_
| than a spoon 's worth of plastic in our brain?
| userbinator wrote:
| IMHO the more important part is they used _pyrolysis_ gas
| chromatography, which breaks down _all_ polymer chains.
|
| Besides man-made plastics, guess what else has long hydrocarbon
| chains, occurs naturally in humans and other biological matter,
| and behaves similarly under pyrolysis...
|
| https://en.wikipedia.org/wiki/Fatty_acid
|
| Here's an interesting related article:
| https://www.oaepublish.com/articles/jeea.2022.04
|
| _Analysis of saturated, monounsaturated and polyunsaturated
| fats was demonstrated to form the same pyrolysis products as
| PE_
| timr wrote:
| To their credit, they do discuss this in the results. I
| suspect the reviewers had the same concerns.
|
| Their response is not especially convincing, IMO, but they do
| at least discuss it.
| jondwillis wrote:
| Really regretting chewing on all of those straws as a kid, eating
| hot food out of all of those takeout trays, keeping my car
| windows open, living near roads... and...
| _sys49152 wrote:
| I rode a hard plastic bike seat on my bmx to school and back
| everyday. eyes emoji. my kids i shoot out will be g.i. joe
| figurines
| odyssey7 wrote:
| Is there no molecule that could be designed which would break
| down microplastics throughout the body, without harming
| biological materials? Or even just the blood stream?
|
| I'm not a chemist, but it seems like if this can be done it would
| be huge.
| ed_mercer wrote:
| Even if you could invent it, I don't think there would be
| demand for it (yet)
| deadbabe wrote:
| Imagine if microplastics in the brain could somehow be utilized
| by neurons for really long term memory storage or something.
| TZubiri wrote:
| No
| SV_BubbleTime wrote:
| Nonsense article, you could fit way more than that.
| mondobe wrote:
| Perfect, I was hoping to increase my neuroplasticity.
| knowitnone wrote:
| I recognize and acknowledge your humorous post.
| Sparkyte wrote:
| It totally struck my funny bone. It was very humerus.
| HaZeust wrote:
| Nice.
| booleandilemma wrote:
| Does it have a negative effect on us though?
|
| I mean, assuming I do have a spoon's worth of microplastics in my
| brain, I don't notice any impairment.
|
| I write JavaScript just fine.
| latentcall wrote:
| So are we okay with this? We don't want to hurt industries or the
| market so we should accept this, right? I think it's extremely
| important that Nestle and Coca Cola continue to be successful. I
| certainly don't mind eating plastic if it means the market does
| well.
|
| Okay I'm sorry for the snark but when these articles come up some
| are like "the studies are inconclusive of the effects" but I'm
| just like "there's plastic in your brain!"
| yapyap wrote:
| baity headlines that scare the shit out of you, exactly what I'm
| NOT looking for on HN
| synergy20 wrote:
| why did not they got flushed by our digestive system,yes micro
| plastics are tiny,still they are too large to get into arteries
| and veins thus no way to reach the brain?
| stevenwoo wrote:
| 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...
| synergy20 wrote:
| Great to know the insights! It seems inevitable though as
| plastics are everywhere.
| kaiwen1 wrote:
| Pre-print paper that concludes "may", so by implication, also
| "may not".
|
| And also may, or may not, be harmful.
| renewiltord wrote:
| Sounds like methodological error. Like your black spatulas.
| Somewhere they've divided by zero, clamped, and averaged or
| something dumb like that.
| purplezooey wrote:
| Well, Vonnegut was right. It's just a dog's breakfast.
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