(vi) Mercury
Mercury can be absorbed by the skin, respiratory tract, and digestive tract,
injuring the brain and liver (Mahar et al. 2016).
(vii) Arsenic
Arsenic metal by nature does not exist in a free form; it usually exists as a
metalloid. Its arsenide form is commonly seen with its association in sulfurcontaining ores. When in arsenate form it disturbs the cellular functions of living
organisms by affecting the process of ATP synthesis and oxidative phosphorylations. Arsenic toxicity can actually reduce the chance of pregnancy and also inhibits
enzyme activity (Tripathi et al. 2007).
(viii) Selenium
All living beings depend on selenium, as it is one of the essential trace elements.
At excessive concentrations (>2.0 mg/kg), however, it causes selenosis and can be
lethal (Li et al. 2013).
4 Phytoremediation of Toxic Metals
The possible green ways to abolish metal pollution include either removing it
completely from the environment by the assistance of plants or making it unavailable
to the crop, followed by a different process of immobilization. The former is called
phytoremediation, which in detail is transferring the pollutants in the environment to
the plant or decomposition, immobilizing the pollutants by rhizosphere processes,
and achieving the removal of pollutants and restoration of the ecological environment through the recycling of plants. Phytoremediation, when compared to the
traditional physical and chemical alternatives of remediation techniques, shows
technological improvement with sustainable remediation effects. It has been largely
applied to the restoration of underground water and surface water by removal of
HMs and organic and inorganic pollutants from soil. When compared with HMs,
other pollutants can be biodegraded and simplified to non-bioavailable, less toxic
components from a mother compound, whereas it is very difficult for HMs to take a
less toxic or unavailable form and to be degraded or removed from the environment,
signifying their indestructible nature.
4.1 Types of Phytoremediation and Mechanisms
In theory, the types of phytoremediation and mechanisms include phytoextraction,
rhizodegradation, phytodegradation, phytostabilization, and phytovolatilization.
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M. K. Awasthi et al.
Mercury can be absorbed by the skin, respiratory tract, and digestive tract,
injuring the brain and liver (Mahar et al. 2016).
(vii) Arsenic
Arsenic metal by nature does not exist in a free form; it usually exists as a
metalloid. Its arsenide form is commonly seen with its association in sulfurcontaining ores. When in arsenate form it disturbs the cellular functions of living
organisms by affecting the process of ATP synthesis and oxidative phosphorylations. Arsenic toxicity can actually reduce the chance of pregnancy and also inhibits
enzyme activity (Tripathi et al. 2007).
(viii) Selenium
All living beings depend on selenium, as it is one of the essential trace elements.
At excessive concentrations (>2.0 mg/kg), however, it causes selenosis and can be
lethal (Li et al. 2013).
4 Phytoremediation of Toxic Metals
The possible green ways to abolish metal pollution include either removing it
completely from the environment by the assistance of plants or making it unavailable
to the crop, followed by a different process of immobilization. The former is called
phytoremediation, which in detail is transferring the pollutants in the environment to
the plant or decomposition, immobilizing the pollutants by rhizosphere processes,
and achieving the removal of pollutants and restoration of the ecological environment through the recycling of plants. Phytoremediation, when compared to the
traditional physical and chemical alternatives of remediation techniques, shows
technological improvement with sustainable remediation effects. It has been largely
applied to the restoration of underground water and surface water by removal of
HMs and organic and inorganic pollutants from soil. When compared with HMs,
other pollutants can be biodegraded and simplified to non-bioavailable, less toxic
components from a mother compound, whereas it is very difficult for HMs to take a
less toxic or unavailable form and to be degraded or removed from the environment,
signifying their indestructible nature.
4.1 Types of Phytoremediation and Mechanisms
In theory, the types of phytoremediation and mechanisms include phytoextraction,
rhizodegradation, phytodegradation, phytostabilization, and phytovolatilization.
88
M. K. Awasthi et al.