I have seen knotweed talked about for metals removal as well. it grows quickly so you can cut and carefully discard the growth and the patch will keep working. Might not cure our soils overnight but having an invasive battle industrial waste is makes for a cool antihero story.
Why is it that S. viminalis and other mentioned Salix species are so effective at this? Is it that the Salix genus is more effective or are more genuses (geni?) also effective but just haven't been studied yet?