and anthropogenic pollutants (Reichenauer and Germida 2008; Singh et al. 2003). It
is possible to find a wide variety of plant species that can colonize areas highly
polluted with heavy metals and metalloids such as mine tailings or soils degraded
and contaminated by mining/industrial activities. These are referred to as
metallophyte and pseudometallophyte species. Some of the plants used in
phytoremediation are: Alfalfa (Medicago sativa), Hybrid Poplar trees (Populus),
blue-green algae (Cyanobacteria), duck weeds (Lemnoideae), Arrowroot (Maranta
arundinacea),Sudan grass (Sorghum drummondii),ryegrass (Lolium), bermuda grass
(Cynodon dactylon), alpine bluegrass (Poa alpina), yellow or white water lilies
(Nymphaeaceae), Sunflower (Helianthus), vetiver grass (Chrysopogon zizanioides),
poplar tree (Populus), brake fern (Pteris), Carrot (Daucus carota subsp. sativus),
periwinkle (Catharanthus roseus), switch grass (Panicum virgatum), white reddish
(Raphanus sativus) (Vasavi et al. 2010), Brassica juncea (Indian mustard) and
Brassica carinata (Ethiopian mustard), members of family Cruciferae
(Brassicaceae).
Metallophytes are plant species of natural mineralized soils and have been
developed physiological mechanisms of resistance and tolerance to survive on
substrates with high metal levels. Metallophytes are hyper-accumulator and relatively rare usually produce biomass. On the other hand pseudo metallophytes species
are contaminated soils. Pseudo metallophyte species or facultative metallophytes
aren’t specialized in metalliferous soils and have a more extensive distribution, but,
due to selective pressure, are capable to survive in metalliferous soils. Thus, the high
pressure of metalliferous soils is natural or contaminated by human action and allows
the selection of populations of common species, with higher tolerance than other
populations of the same species. Therefore, their capacity of adaptation to these
environments, accumulation of metals and metalloids can be very interesting with a
view to their use like in ecological restoration, phytoremediation, and bio-indication
actions. In recent decades many studies have been conducted in contaminated
mining and industrial areas and in natural metalliferous soils in order to inventory
and screen the indigenous species and evaluate their potential for phytoremediation
of contaminated soils in the rhizofiltration these plants are cultivated in a hydroponic
manner. When the root system is well developed, the plants are introduced into the
water contaminated with metals, where the roots absorb and accumulate them. As
the roots become saturated, the plants are harvested and disposed for their final use
(Cherian et al. 2006; Eapen et al. 2003; Nedelkoska et al. 2000) (Table 13.1).
13.1.2 Classification of Phytoremediation
13.1.2.1 Phyto-degradation (Phyto-transformation)
Contaminants are taken up into the plant tissues where they are metabolized and
biotransformed. Transformation takes place depends on the type of plant and can
occur in roots, stems and leaves. The process includes specific enzymes like:
nitroreductases (degradation of nitroaromatic compounds), dehalogenases
13 Phytoremediation and Nanoremediation
283
is possible to find a wide variety of plant species that can colonize areas highly
polluted with heavy metals and metalloids such as mine tailings or soils degraded
and contaminated by mining/industrial activities. These are referred to as
metallophyte and pseudometallophyte species. Some of the plants used in
phytoremediation are: Alfalfa (Medicago sativa), Hybrid Poplar trees (Populus),
blue-green algae (Cyanobacteria), duck weeds (Lemnoideae), Arrowroot (Maranta
arundinacea),Sudan grass (Sorghum drummondii),ryegrass (Lolium), bermuda grass
(Cynodon dactylon), alpine bluegrass (Poa alpina), yellow or white water lilies
(Nymphaeaceae), Sunflower (Helianthus), vetiver grass (Chrysopogon zizanioides),
poplar tree (Populus), brake fern (Pteris), Carrot (Daucus carota subsp. sativus),
periwinkle (Catharanthus roseus), switch grass (Panicum virgatum), white reddish
(Raphanus sativus) (Vasavi et al. 2010), Brassica juncea (Indian mustard) and
Brassica carinata (Ethiopian mustard), members of family Cruciferae
(Brassicaceae).
Metallophytes are plant species of natural mineralized soils and have been
developed physiological mechanisms of resistance and tolerance to survive on
substrates with high metal levels. Metallophytes are hyper-accumulator and relatively rare usually produce biomass. On the other hand pseudo metallophytes species
are contaminated soils. Pseudo metallophyte species or facultative metallophytes
aren’t specialized in metalliferous soils and have a more extensive distribution, but,
due to selective pressure, are capable to survive in metalliferous soils. Thus, the high
pressure of metalliferous soils is natural or contaminated by human action and allows
the selection of populations of common species, with higher tolerance than other
populations of the same species. Therefore, their capacity of adaptation to these
environments, accumulation of metals and metalloids can be very interesting with a
view to their use like in ecological restoration, phytoremediation, and bio-indication
actions. In recent decades many studies have been conducted in contaminated
mining and industrial areas and in natural metalliferous soils in order to inventory
and screen the indigenous species and evaluate their potential for phytoremediation
of contaminated soils in the rhizofiltration these plants are cultivated in a hydroponic
manner. When the root system is well developed, the plants are introduced into the
water contaminated with metals, where the roots absorb and accumulate them. As
the roots become saturated, the plants are harvested and disposed for their final use
(Cherian et al. 2006; Eapen et al. 2003; Nedelkoska et al. 2000) (Table 13.1).
13.1.2 Classification of Phytoremediation
13.1.2.1 Phyto-degradation (Phyto-transformation)
Contaminants are taken up into the plant tissues where they are metabolized and
biotransformed. Transformation takes place depends on the type of plant and can
occur in roots, stems and leaves. The process includes specific enzymes like:
nitroreductases (degradation of nitroaromatic compounds), dehalogenases
13 Phytoremediation and Nanoremediation
283