Comment by pdonis | Hacker News Reader

Comment by pdonis | Hacker News Reader

When you put the numbers in context, they are tiny.

For example, consider this comparison: when you take a pill of some drug, say an aspirin tablet, how much of the active ingredient (aspirin in this case) are in that pill? And how many bottles of water would you have to drink to put the same amount of nanoplastics (treating them as an "active ingredient") into your body?

Here's a back of the envelope calculation: suppose the concentration of nanoplastics is 10 nanograms per liter (about what is claimed in the article). A liter is about one (fairly large) bottle of water, so say 10 nanograms per bottle. A standard aspirin tablet has 325,000,000 nanograms (325 milligrams) of aspirin in it, or 32.5 million times as much active ingredient. So you would have to drink 32.5 million 1-liter bottles of water to expect the same general order of magnitude of "active ingredient" effects on your body as one aspirin tablet. If you drank one bottle of water per second, it would take you more than 10 years to drink that much water.

So I don't see any reason to forgo bottled water on these grounds. Certainly not in favor of tap water, which is much more subject to how careful your municipality's water purification process is (not to mention various possible sources of contamination in the water lines between the purification plant and the water tower and you).

The NIH has begun doing studies on the effects of nanoplastics, and it appears there is evidence for buildup in the liver [1]. If asprin had a long half-life in your body, you'd have a maximum lifetime dose. The reason it makes a good medicine is due to the fact that it has a positive effect and leaves your body in a timely manner.

A good example in this instance is Lead. Its bad to have lead in your water even in relatively small amounts, because the half-life of lead in your soft tissues is months, and in your bone is 20-30 years. If nanoplastics end up being similar, you could end up with liver damage, or other medical complications if your exposure is high.

[1] - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9610555/

There would be very little economic effect if everyone in the world got a reverse osmosis drinking-water only filter ($200 every 10-15 years, $20-30 a year). Though we don't have any kind of structure that could actually make that happen.

The article suggests the source of nanoplastics in tap water is from reverse osmosis PA filters.

Even if you assume permanent lifetime build up, it seems like we're talking about ~10 nanograms per liter (as per grandparent post) of these plastics versus 15,000 nanograms per liter of lead that meets EPA safety limits.

I find it hard to assume the plastic should be more than a thousand times more worrisome than lead on a per-gram basis (That said, we have persistently underestimated the negative effects of the element.)

Appreciate the context, but the magnitude of effect of drugs also varies by some orders of magnitude - so it's possible/likely that the concentrations that build up over a lifetime in the body could be having some negative effect.

> it's possible/likely that the concentrations that build up over a lifetime in the body could be having some negative effect.

See my response to globular-toast downthread.

>So you would have to drink 32.5 million 1-liter bottles of water to expect the same general order of magnitude of "active ingredient" effects on your body as one aspirin tablet.

Only if aspirin is what the bottle is leeching into the water.

Yeah agreed, worth noting that it only takes ~100-1000 nanograms of Botulinum toxin to kill you. So it’s kind of irrelevant to compare different substances toxicity based on quantity alone. The toxic levels of aspirin are totally irrelevant for a different substance

https://en.m.wikipedia.org/wiki/Botulinum_toxin

> it’s kind of irrelevant to compare different substances toxicity based on quantity alone

While this is true, it applies with even more force to the comparison with botulinum toxin than to the comparison with aspirin. Nanoplastics are less active than aspirin, not more (there's a reason why nobody takes nanoplastics to cure headaches), so if anything one would expect to require more nanoplastics than aspirin to have a significant effect--which means even much more more, so to speak, than botulinum toxin.

Yeah but things like aspirin don't accumulate in the body. If the plastics are accumulating then you might very well have an active dose after years of consumption. People born today are going to be consuming this stuff every day for their entire lives.

> If the plastics are accumulating then you might very well have an active dose after years of consumption.

After how many years of consumption? If we suppose that every single nanoplastic molecule that enters your body never leaves it (which is not going to be the case, but will give us an absolute lower bound to the time required), it would still take 32.5 million one-liter bottles to accumulate as much as one aspirin tablet. Say you drink six of those bottles a day, which is more than just about anyone actually drinks. That's about 2200 bottles a year. Meaning it would take you about 16,000 years to accumulate as much as one aspirin tablet.

It's only 16 years to accumulate as much as one LSD dose, though.

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