That should depend on how the chemicals accumulate though. If all the plastic ends up in your blood and never gets naturally filtered out, it could make sense. Maybe it builds up in your fat/muscles instead though, or gets filtered over time and the amount in your system is the same as the amount in what you have recently eaten, idk
It isn't. Blood donation reduces PFASs and iron buildup (too much iron in the blood is bad). And leeches are used in certain procedures, although I haven't heard of them being used to remove microplastics (yet).