Water soluble and exchangeable lead are the only fractions readily available for uptake by plants.
Oxyhydroxides, organic, carbonate, and precipitated forms of lead are the most strongly bound to the soil.
The capacity of the soil to adsorb lead increases with increasing pH, cation exchange capacity (CEC), organic
carbon content, soil/water Eh (redox potential) and phosphate levels. In the natural setting, lead
hyperaccumulation has not been documented. However, certain plants have been identified which have the
potential to uptake lead (Henry 2000).