I think the idea is the calcium carbonate traps it but not sure why or how efficient it is. Or if you boil microplastics do they melt (become petrol or oil?) or do they stay intact or a mix.
So the calcium carbonate traps both the nanoplastic and also any chemicals that leach out during boiling?
The most commonly encountered plastics (Polyethylene, and Polypropylene) don't leech anything. It's mostly vinyl that leeches, and that's not a common microplastic.