The plants that actually manage to absorb lead translocate little to the shoots. You get lead glomming up into root cells. As a short term solution, Cunningham advocates phytostabilization, which chemically altars rather than removes toxins. In phytostabilization, soil amendments isolate the metal, making it biologically unavailable. For instance, iron oxyhydroxides, fixate stray lead in soil.
Plants then stabilize the soil, preventing erosion.
Thus, metal is transformed or trapped beneath the reach of wandering children or animals. For easier metals, like zinc or nickel, a little chemical coaxing can increase solubility. For instance, adding acidifiers to soil boosts metal absorption in plants. Soil, of course, is not the only contaminant carrier. In the United States, industrial discharge, agricultural runoff, and acid mine drainage contaminate surface and ground water.