1.5 Mechanisms of Phytoremediation [30, 31]
The mechanism by which phytoremediation takes place depends on the type of the
contaminant being treated. The mechanisms may be broadly classified as
phytoextraction, phytodegradation, rhizofiltration, phytostabilization, and
phytovolatilization.
1.5.1 Phytoextraction
Phytoextraction is also called as phytoabsorption, phytoaccumulation, and
phytosequestration. It removes metals or organics from soils and accumulates
them in the biomass of harvestable plants by root and surface shoots. It is the uptake
of the contaminant from the soil by the plant roots and can be concentrated and
translocated from the soil into the harvestable part [32] of the roots or shoots and
above the soil surface [29]. The contaminants are not destroyed but are accumulated
in various parts of plant such as shoots, leaves, etc. [33]. Figure 1 presents the
schematic representation of phytoextraction. Phytoextraction has been basically
divided into two strategies: induced phytoextraction and long term-continuous
phytoextraction.
Fig. 1 Phytoextraction
Phytoremediation of Soil for Metal and Organic Pollutant Removal
49