Landfills not being underground is even worse (but normally they are buried under soil when they go unused).

While the plastics degrade mechanically, being reduced into small particles, chemically they are not. They just turn into microplastics which I’m sure you’re aware is a huge problem.

With the small amount of ultimate nuclear waste that cannot be reprocessed further, the solution is simple: drill a km deep shaft into the bedrock, place them at the bottom, fill the shaft with rubble and cement. Done. No-one’s going to accidentally dig them up and they pose absolutely no threat to anyone. The finns are doing something like this as we speak.