PHYTOREMEDIATION
Compiled By: Dr. Farooq Ahmad
Phytoremediation
• Phytoremediation is considered an effective, aesthetically
pleasing, cost effective and environmental friendly technology
for the remediation of potentially toxic metals from the
environment.
• Plants in phytoremediation accumulate contaminants through
their roots and then translocate these contaminant in the
aboveground part of their body.
• The notion of using metal accumulator plants for the removal of
heavy metals and several other contaminants in
phytoremediation was first introduced in 1983, but this idea has
already been implanted for the last 300 years.
Compiled By: Dr. Farooq Ahmad
• Phytoremediation is known by different names such as
agro-remediation, green remediation, vegetative
remediation, green technology and botano remediation.
• An enormous number of contaminants can be remediated
by phytoremediation technology such as insecticides,
chlorinated solvents, Polycyclic aromatic hydrocarbons
(PAHs), Polychlorinated biphenyl (PCBs), petroleum
hydrocarbons, radio nucleosides, surfactants, explosive
elements and heavy metals.
• There are a number of plant species that have the ability
to accumulate significantly higher concentrations of heavy
metals in different parts of the body, such as a leaf, stems
and root, without showing any sign
Compiled By: Dr. Farooq Ahmad
of toxicity.
Characteristics of Phytoremediation Plants
Plants should have the following characteristics
• native and quick growth rate,
• high biomass yield,
• the uptake of a large amount of heavy metals,
• the ability to transport metals in aboveground parts of
plant, and
• mechanism to tolerate metal toxicity.
• Other factors like pH, solar radiation, nutrient
availability and salinity greatly influence the
phytoremediation potential and growth of the plant.
Compiled By: Dr. Farooq Ahmad
Mechanism of Phytoremediation
Phytoremediation follows different mechanisms
such as
1. phytoextraction,
2. phytostabilization,
3. phytovolatilization and
4. rhizofiltration during the uptake or
5. accumulation of heavy metals in the plant.
Compiled By: Dr. Farooq Ahmad
Phytoextraction
• Phytoextraction involves the uptake of heavy metal in the plant
roots and then their translocation into an above ground-level
portion of the plant.
• Once the phytoextraction is done the plant can be harvested and
burned for gaining energy and recovering/recycling metal.
• Sometimes phytoremediation and phytoextraction are used
synonymously, which is a misconception.
• Phytoextraction is a cleanup technology while phytoremediation
is the name of a concept.
• Phytoextraction is an suitable phytoremediation technique for
the remediation of heavy metals from wastewater, sediments
and soil. Compiled By: Dr. Farooq Ahmad
Phytostabilization
• Phytostabilization involves the use of the plant to
restrict the movement of contaminants in the soil.
• Remediation of soil, sludge, and sediment can be
effectively done by using this technology.
• When we need to persevere in our surface water,
ground water and restoration of soil quality, this
technology is best suited for this purpose because it
cuts short the movement of the contaminants.
• It is not a permanent resolution, because only the
movement of metals is restricted, but they continue to
stay in the soil. Compiled By: Dr. Farooq Ahmad
Rhizofiltration
• Rhizofiltration involves the use of the plant to ab/adsorb
the contaminants, resulting in restricted movement of
these contaminants in underground water.
• Once the plant has soaked up all the contaminants, they
can easily be harvested and disposed.
• Plants for rhizofiltration should have the ability; to produce
a widespread root system, accumulate high concentrations
of heavy metals.
• Both aquatic and terrestrial plants with long fibrous root
systems can be used in rhizofiltration.
Compiled By: Dr. Farooq Ahmad
Phytovolatilization
• Phytovolatilization is the process in which a plant converts
pollutants into a different volatile nature and then their
successive release into the surrounding environment with
the help of the plant’s stomata.
• Plant species like canola and Indian mustard are useful for
the phytovolatilization of selenium.
• Mercury and selenium are the most favorable
contaminants that can be remediated in
phytovolatilization.
• One of the greatest advantages of phytovolatilization is
that it does not require any additional management once
the plantation is done.Compiled By: Dr. Farooq Ahmad
Advances in Phytoremediation
Chemical Assisted Phytoremediation
• The application of specific chemicals has proved to be a
successful technique to boost the bioavailability of heavy
metals to plants.
• Organic fertilizers and chelating reagents are commonly
used to decrease the pH of soils, which ultimately
enhance the bioavailability.
• In tobacco, decreased pH by application of a chelating
reagent showed increased accumulation of Cd.
• The application of ethylenediaminetetraacetic acid (EDTA)
boosted the phytoextraction and bioaccumulation of Cd,
Zn, and Pb in various studies
Compiled By: Dr. Farooq Ahmad
Microbial Assisted Phytoremediation
• Plant-associated microorganisms have a key role in
the remediation of heavy metals from soils.
• These microorganisms influence the availability and
accumulation of heavy metals in soil and plants.
• Plant growth-promoting rhizobacteria (PGPR)
proved to increase biomass production, disease
resistance, and reduce metal induced toxicity in bio-
augmented plants.
• Similarly, endophytic bacteria also play a very
prominent part in phytoremediation
Compiled By: Dr. Farooq Ahmad
Transgenic Plants
• Specific genes in transgenic plants increase the metabolism,
accumulation and uptake of definite pollutants.
• The ideal plant to engineer for phytoremediation should
possess characteristics; high biomass yield adopted to
local and target environment and well-established
transformation protocol.
• Transgenic plants also enhance the detoxification process of
organic pollutants and the addition of toxic compounds in
the food chain.
• Firstly, transgenic plants were introduced for the remediation
of inorganic pollutants; now they are effectively used to
remove organic pollutants from contaminated media.
Compiled By: Dr. Farooq Ahmad
Non-Living Plant Biomass
• Non-living plant biomass can be profitably used for metal
uptake and metal recovery.
• Successive use of dried and dead biomass of plants (as simple
biosorbent substance) to remove the metals from water has
gained popularity.
• It is easy to handle and is a cost-effective approach.
• Water hyacinth’s (Eichornia crassipes) dried roots showed the
potential to remove cadmium and lead effectively from
wastewater.
• Biomass of different aquatic plant species such as
Eichhornia crassipes, Potamogetonlucens, and Salvinia
herzegoi was reported to be successfully used as an
exceptional biosorb
Compiled By: Dr. Farooq Ahmad
Aquatic Plants and Phytoremediation
• Removal of different heavy metals along with other
contaminants through the application of aquatic plants
is the most proficient method.
• Constructed wetlands along with aquatic plants were
extensively applied throughout the world for the
treatment of wastewater.
• The selection of aquatic plant species for the
accumulation of heavy metal is a very important matter
to enhance the phytoremediation.
• The growth and cultivation of aquatic plants are time-
consuming, which may restrict the growing demand of
phytoremediation.
Compiled By: Dr. Farooq Ahmad
Compiled By: Dr. Farooq Ahmad
Submerged Aquatic Plants
• In submerged aquatic plants, leaves are the main part for metal
uptake.
• Polyglalacturonic acid of the cell wall and negatively charged cutin
and pectin polymers of cuticle results in the sucking inward of
minerals.
• Examples include parrot feather (Myriophyllum spicatum),
pondweed (Potamogeton Crispus), American pondweed
(Potamogeton pectinatus) etc.
Emergent Aquatic Plants
• These plants are usually found on submerged soil where the water
table is 0.5 m below the soil.
• Accumulation of HMs in emergent plants varies from plant to plant
• Smooth cordgrass (spartina alterniflora) take up heavy metals in
leaves while common reed (Phragmites
Compiled australis) store in the roots.
By: Dr. Farooq Ahmad
Significance of Aquatic Plants for Phytoremediation
of Wastewater
Phytoremediation of Municipal Wastewater
• Application of aquatic plants for the removal of heavy metals
from municipal wastewater, sewage water, spillage areas, and
other polluted sites has become a common experimental
technique.
• U, As and B were rapidly absorbed by the plant during the first 2
days of a 7-day experimental study.
• Two rooted macrophytes Typha angustifolia and Phragmites
australis removed 14–85% of heavy metals such as zinc, lead,
arsenic, nickel, iron, copper, aluminum and magnesium from
municipal wastewater. Compiled By: Dr. Farooq Ahmad
Phytoremediation of Industrial Wastewater
• Discharge of industrial waste into soil and water signifies a
more critical threat to human health, living organisms, and
other resources.
• Phytoremediation occurs by phytostabilization
and phytoextraction.
• Aquatic plants Pistia stratiotes, Azolla pinnata,
and Salvinia, molesta were found very competent
for the elimination of Fe, Cu and Mn
• Results demonstrated excellent removal efficiencies: Cd
(90%), Cr (89%), Fe (74.1%), Pb (50%), Cu (48.3%) and Ni
(40.9%), respectively
Compiled By: Dr. Farooq Ahmad
Phytoremediation of Mining Effluents
• Mining activities harmfully affect the whole
environment and put an incredible burden on local fauna
and flora.
• Effluents of mining activities hold a higher concentration
of different pollutants like calcium carbonate, TDS, TSS
and heavy metals.
• Heavy metals originating from the mining effluents are
very persistent in nature and can easily accumulate in the
soil, water, sediment
• Phytoremediation is such a method that showed
promising results on mining effluents by employing
aquatic macrophytes. Compiled By: Dr. Farooq Ahmad
Phytoremediation of Landfill Leachate
• Landfilling and open dumping are the most common way
of treating municipal solid waste (MSW) worldwide.
• Generated landfill leachate if not properly managed, can
easily lead towards numerous adverse health and
environmental impacts.
• Phytoremediation is very successful in the treatment of
landfill leachate.
• Plants such as Gynerium sagittatum (Gs), Colocasia
esculenta (Ce) etc. have shown tremendous
phytoremediation potential for the remediation of
landfill leachate. Compiled By: Dr. Farooq Ahmad
