[AstralStorm]

Most problems with plastics are chemical not physical contamination. (It is a solution of plasticizers and substrates in water.)

I am pretty sure ingesting plastic sand would be nowhere newer bad without these. (Intestine shouldn't take that in.)

These are extra hard to filter out. Even big fermentation tanks and reverse osmosis filters have problems with this.

[haZard_OS]

There is also the danger of microplastic particles acting as endocrine disruptors. This is a rapidly developing field within (eco)toxicology and is of growing concern among environmental scientists.

https://pubs.acs.org/doi/10.1021/acs.est.6b01441

https://www.sciencedirect.com/science/article/pii/S026974911...

https://www.sciencedirect.com/science/article/pii/S004896971...