Upon discovering roller coaster fossils, future intelligence might conclude that we must have had vertical communities with intricate mass transportation throughout to quickly get from floor 40 to B2 and that residents had balls of steel and impressive grip strength once undeniable proof of loops is shown. Because if there's only one station, riders would need to either exit or enter while it was still moving.
I mean lead is pretty tastey, romans figured that out. But guy in year 10,000 is still going to have microplastics, the entire earth has been irreversibly infected.
Guy in year 10k may be spared microplastics, if society figures out how to do so and also decides it is worth it to do so. That's a lot of years to, for example, come up with nanites that break microplastics down into component bits.