The bioavailability of metals in soil is a dynamic process that depends on specific combinations of chemical,
biological, and environmental parameters. In heavy metal polluted soils, plant growth can be inhibited by metal
absorption. However, some plant species are able to accumulate fairly large amounts of heavy metals without
showing stress, which represents a potential risk to animals and humans. The level of plant tolerance to heavy
metals is related to the balance between the rate at which metal ions are taken up and the efficiency with which they
are detoxified within the plant. Thus the same amount of a metal present in plant tissues may be detrimental for one
species while not at all for others.