Comment by kjs3

My dad was in hazardous waste abatement (see: US Superfund cleanups), and I talked to a guy at a corp party years ago who was researching plants growing on slag. But he was looking at the plants that were sucking up the abundant toxins present in slag with an eye towards environmental cleanup (slowly). Slag is often very nasty stuff, and certain plants (no, I don't know which) were really good at sucking up and sequestering the nastiness.