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Comment by Exuma | Hacker News Reader

I was wondering this literally yesterday... are there any current methods for filtering out microplastics? Currently I just have a filter within my fridge for drinking water... but I take it that doesnt do much

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The simple carbon filter in your fridge should suffice. Sub micron microplastic (nanoplastics) have not been detected yet, and their sustained existence remains speculative.

If you are still worried, just install a reverse osmosis system. It also has the benefit of filtering away sub-nanometer particles that are actually proven to have negative health effects (such as heavy metals and bacteria).

When microplastics break down they get smaller and become nanoplastics.

Nanoplastics have been detected.

Here is a paper that shows how to measure nanoplastics. Dilute solutions with polystyrene particles from 400nm down to 40nm were prepared and measured.

Demineralized water was put in a polystyrene cup. Microplastics were removed and the remaining nanoplastics were measured. A concentration of ~10^12 particles/l was found.

https://pubs.rsc.org/en/content/articlelanding/2021/en/d0en0...

They've been detected in a synthetic lab condition, but not in the wild.

It'd be a bit weird if they weren't in the wild though, wouldn't it?

The point is that their half life in the wild is so short that their presence is negligible.

In the paper, the nanoplastics were measured in demineralized water that had been sitting in a regular disposable polystyrene cup (like the ones that people drink coffee from) for five minutes.

So the measurement reflects the nanoplastics that one ingests when drinking a cup of coffee from a polystyrene cup.

Because nanoplastics sizes are of the order of the wavelength of visible light, the particles were measured with fluorescence microscopy.

Nanoplastics were also found in high concentrations in store bought plastic bottles of mineral water as well as in water that had been sitting in baby bottles.

One thing to be aware of, is some filters system have been found to introduce microplastics. I think it’s primarily the container/piping that does this, but it’s been a long while since I’ve looked at things. It’s not unreasonable to consider the filter housing also as a source.

carbon filters do filter out quite a bit, but not all, so it's hardly "not much". A quick search will show you filtering down to 1-5um sizes

I have a reverse osmosis system for my well water that filters out both PFAS and micro plastics.

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