1,3,5-hexahydrotriazine (RDX); hydrocarbons such as benzene, toluene, and xylene
(BTX); and pesticides such as atrazine [20].
The use of bioremediation as a treatment strategy for contaminated environments
has gained a lot of interest due to its viability and low cost [17, 21, 22]. In
bioremediation microorganisms (fungi, bacteria) and plants (phytoremediation) are
used for the removal of contaminants from the soil [23, 24]. Microorganisms may
mineralize or neutralize the hazardous contaminants. Microbial-based bioremediation uses specialized strains of bacteria with capability of consuming the targeted
contaminants [25]. Plants can also be used to consume CO 2 and other gaseous
industrial effluents [26]. Remediation using plants is termed as phytoremediation,
and it has already received significant scientific and commercial attention.
1.4 The Emergence of Phytoremediation
The employment of the plants alone or in association with microorganism to
remediate the soil, water, and air by degradation or stabilization of various environmental contaminants present in them is known as phytoremediation [27]. It is a
non-intrusive, effective, and inexpensive means to remediate the soil. The technology is cost-effective than the mechanical or chemical methods for removal or
degradation of hazardous compounds from the soil [12]. Every plant extracts the
essential nutrients from the soil and water including metals. Plants which have the
ability to store huge amount of metals are known as hyperaccumulators. They can
uptake even metals that do not appear to be required for their physiological functioning processes [28]. However, the applicability of phytoremediation can be
flashed up to low to moderate concentration of contaminant, so as to allow the
plant to survive, germinate, and grow at the same time. In regard to plant biological
system, there are essential heavy metals which are required by the plant in minute
quantities, and they play a vital role in physiological and biochemical function.
Essential heavy metals such as Fe, Ni, Mn, Cu, and Zn are essential, whereas the
heavy metals which are not needed by the plant for its physiological and biochemical
process like As, Hg, Cr, Cd, Pb, etc. are known as non-essential metals. If uptake of
such metals becomes higher than its threshold, it may interfere to its normal plant
functions [29]. In addition, genetic engineering is now being conducted for the
improvement in plant natural capabilities to perform the remediation process better.
Advantages of phytoremediation are the following: (1) it is an aesthetically solardriven cleanup technology; (2) minimal disruption to the environment which preserves the top soil in in situ treatment; (3) cost-effectiveness, i.e., 60–80% lesser than
conventional methods; (4) suitable, where the contaminants are at low level and
shallow sites; and (5) broad-spectrum treatment of environmental contaminants.
However, one of the drawbacks is that it is a time-consuming process because the
plant may take a lot of time to grow [27].
48
S. Sophia and V. Shetty Kodialbail
(BTX); and pesticides such as atrazine [20].
The use of bioremediation as a treatment strategy for contaminated environments
has gained a lot of interest due to its viability and low cost [17, 21, 22]. In
bioremediation microorganisms (fungi, bacteria) and plants (phytoremediation) are
used for the removal of contaminants from the soil [23, 24]. Microorganisms may
mineralize or neutralize the hazardous contaminants. Microbial-based bioremediation uses specialized strains of bacteria with capability of consuming the targeted
contaminants [25]. Plants can also be used to consume CO 2 and other gaseous
industrial effluents [26]. Remediation using plants is termed as phytoremediation,
and it has already received significant scientific and commercial attention.
1.4 The Emergence of Phytoremediation
The employment of the plants alone or in association with microorganism to
remediate the soil, water, and air by degradation or stabilization of various environmental contaminants present in them is known as phytoremediation [27]. It is a
non-intrusive, effective, and inexpensive means to remediate the soil. The technology is cost-effective than the mechanical or chemical methods for removal or
degradation of hazardous compounds from the soil [12]. Every plant extracts the
essential nutrients from the soil and water including metals. Plants which have the
ability to store huge amount of metals are known as hyperaccumulators. They can
uptake even metals that do not appear to be required for their physiological functioning processes [28]. However, the applicability of phytoremediation can be
flashed up to low to moderate concentration of contaminant, so as to allow the
plant to survive, germinate, and grow at the same time. In regard to plant biological
system, there are essential heavy metals which are required by the plant in minute
quantities, and they play a vital role in physiological and biochemical function.
Essential heavy metals such as Fe, Ni, Mn, Cu, and Zn are essential, whereas the
heavy metals which are not needed by the plant for its physiological and biochemical
process like As, Hg, Cr, Cd, Pb, etc. are known as non-essential metals. If uptake of
such metals becomes higher than its threshold, it may interfere to its normal plant
functions [29]. In addition, genetic engineering is now being conducted for the
improvement in plant natural capabilities to perform the remediation process better.
Advantages of phytoremediation are the following: (1) it is an aesthetically solardriven cleanup technology; (2) minimal disruption to the environment which preserves the top soil in in situ treatment; (3) cost-effectiveness, i.e., 60–80% lesser than
conventional methods; (4) suitable, where the contaminants are at low level and
shallow sites; and (5) broad-spectrum treatment of environmental contaminants.
However, one of the drawbacks is that it is a time-consuming process because the
plant may take a lot of time to grow [27].
48
S. Sophia and V. Shetty Kodialbail