I don't know if people do this in real life (or I would have chosen a different thread), but one obstacle why they would not is lack of infrastructure. Once you get a truckload of toxic waste, what to do with it?.. Also, I hope to have some numbers for one species (actually, for a fraction of its ecoforms) in a limited range of pollutants in a specific geographic area, under specific land use conditions, collaborating with chemists who will hopefully find the problem interesting enough, AND I live in Ukraine. I won't have time for it until after defending my thesis. Give me a Latin name, and I will try to come with a prediction, however off key; but generalizing across orders of flowering plants is simply wrong. (ETA: a nitpick. A lawn is not a HM sink. The soil is far too often disturbed, and new layers are not yearly deposited there. It won't hold the pollutants reliably. Maybe, under some conditions, it is better not to extract them, I will have to think upon it. And the concept of a grass that nobody ever eats blew my mind, it did. Save yourself, man! (Woman, child, alien, AI.) Run! Sell your house to a sci-fi writer and don't look back!)
I'll ask a simpler question. What is the best (in terms of heavy-metal concentration as % of biomass) that a flowering plant can do?
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.