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Comment by ditn | Hacker News Reader

Regularly donating blood or plasma can reduce PFAS concentrations in the body, I believe the effect is the same on microplastics https://theconversation.com/new-evidence-shows-blood-or-plas...

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Super interesting. But is the blood then cleaned of them, or is this kind of like giving your plastics to someone else? :/

If I was in a need of a blood transfusion I think I’m OK with there being a normal amount of nanoplastics in them.

nit, but this is usually accomplished with plasma donation (plasmapheresis) rather than blood donation. You can donate plasma much more frequently (2x/week) vs blood (once per 2 months), thought the volume taken for each is roughly similar.

The filters used must be a specific size, so how micro, are micro plastics? If they keep breaking into smaller pieces, wouldn't they be cell sized too? And thus, pass cell sized filters?

They don't filter the plasma, they remove it and replace with some other substance depending in your condition and risk profile.

You have to filter whole blood, to get plasma.

So you filter out the blood cells (45% of volume), toss the plasma (55% of volume) and return blood cells + clean plasma. Any substances the plasma are gone. So this is useful to the extent that the substances you care about are free in plasma. At least in the case of PFAS ("forever chemicals") that seems to be the case, see "Effect of Plasma and Blood Donations on Levels of Perfluoroalkyl and Polyfluoroalkyl Substances in Firefighters in Australia", which found that 52 weeks of plasma donation reduced PFAS blood levels by ~30%. This was more effective than blood donation, which reduced levels by 10% and 0% depending on the specific substances you look at.

https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

If there are microplastics the size of blood cells (this is a range, as cells are differing sizes), how do you filter for blood cells only?

You can dual filter, smaller and larger than, but you'd still have plastics.

Ah, I see, sorry for missing your point. In the paper they injected particles of size "9.55 µm, 1.14 µm, 0.293 µm", and it looks like a red blood cell is 8um. So a purely mechanical filter that got red blood cells would retain the largest of those particles but potentially not the rest. But plasmapheresis uses a combination of centrifugal separation and filters so may be more or less effective than that depending on the properties of the cells and plastics.

Ah! I was not aware that more than filters were being used. This could certainly help.

Thanks

If I was in a situation where I needed emergency blood, the level of microplastics in it is the least of my concerns.

“Excuse me, did this blood come from a vegan? I couldn’t possibly accept blood that isn’t 100% organic, free range, and —-“ (transcript ends, patient died)

The only feasible way I see for removal is via donation or some form of hemodialysis. As the saying goes, the solution for pollution is dilution (or at least in the medical sense!)

This comes up time and time again. I'd feel worse giving someone else toxic blood that can't be fully filtered.

Why isn't blood letting mentioned more?

You don't need to feel guilty. Microplastics are pervasive to the point where everybody already has them in their blood, so people receiving blood with them in it are getting any noticeably net harm done to them. If you're in need of a blood transfusion the alternative is usually death, so all things considering maintaining the status quo of microplastic levels already in you isn't the worst thing ever.

Or get a shit ton of labs done

How about regular whole blood donations?

You mean bloodletting, because you can't use the blood for others.

I don't think anyone would mind taking on some pfas or microplastics from a donor if they're about to bleed out. There are always priorities.

Especially since we all have PFAS and microplastics in us at this point. There is no PFAS- and microplastics-free blood.

If all donated blood was screened for trace microplastics, I think we’d have an immediate and total donor blood shortage.

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