When I worked for Kimberly-Clark Corporation, the manufacturers of
Kleenix, I managed a project intended to detoxify paper mill sludge. Paper
mill sludge that contains copious amounts of cadmium as well as other heavy
metals is prohibited from being landfilled. While many plants take up these
heavy metals, Equisetum spp., or Scouring Rush, as it is commonly called,
(We mainly worked with E. hyemale) performed the task more efficiently than
any other tested plant. We dug up rhizomes and planted them in concentrated
sludge. Then, at the end of the growing season, we landfilled the
above-ground portion and, after a few growing seasons, the sludge was
sufficiently detoxified to be landfilled.