Phytoremediation

1. Phytoremediation

2. Introduction
• Phyto” means plant (in Greek) “Remediare” means “to heal” in Latin.
• “The productive use of plants to expel, detoxify, or immobilize environmental
pollutants in a growth matrix (soil, water, or sediments) by natural
biochemical or physical activities and process of the plants such as
translocation, bioaccumulation, and contaminant degradation,”
• Natural method:can be an efficient remediation procedure for a wide spectru
m of pollutants and locations.
• A broad variety of toxins can be eliminated, degraded, metabolized, or imm
obilized by some plant species having genetic potential .

3. HOW DOES PHYTOREMEDIATION WORK?
• Phytoremediation is an in-situ remediation
technique that makes use of alive plants' innate abilities .
• The processes and efficacy of phytoremediation are based on
the nature of contaminants , bioavailability, and soil properties.
• The plant roots has a large surface area that absorbs and
accumulates water, nutrients, necessary
for development and other non-essential pollutants.

4. Phytoremediation can be broadly categorised as
To treat Organic
contaminants
1.Phytodegradation
2.Phytovolatilization
3.Phytostimulation
To treat Metal
contaminants
1.Phytoextraction
2.Rhizofiltration
3.Phytostabilization

5. Phytodegradation/
Phytotransformation
• Breakdown of pollutants taken up by plants by metabolic activities or the effe
ct of products formed by the plants (such as enzymes).
• Organic compounds are hydrolyzed into smaller units by metabolic activities
that can be consumed by plants.
• Enzymes found in plants catalyze and intensify chemical reactions.
• Clean up organic chemicals like chlorinated solvents, herbicides, and munitio
ns.

6. Cont...
• It is capable of removing toxins from soil,
sediment, sludge, surface water, and
groundwater.
• Organic compounds are broken down
(degraded) by enzymes in plant roots. The
fragments are incorporated into a new plant
material
• Example:
Using a hybrid poplar tree, trichloroethylen
e (TCE), a common ground water contamin
ant, converted to less toxic metabolites.

7. Phytovolatilization
• Plants draw in water-
soluble pollutants from the soil, convert them to volatile forms,
and then transpire them into the atmosphere.
• Phytovolatilization is most widely used in groundwater, but it ca
n also be used in soil, sediments, and sludges.
• Works on organic molecules, heavy metal toxins, and TCE, am
ong other things.
• Mercury is the most common metal pollutant for which this met
hod has been used.
• Example:
At one study site, poplar trees were observed to volatilize 90 p
ercent of the TCE they ingested

8. Phytostimulation
• Rhizosphere bioremediation, plant assisted bioremediation, and rhizodegrada
tion are all words for the same matter.
• Is the microbial action that breaks down pollutants in the rhizosphere, which is
aided by the presence of plant roots.
• Sugars, alcohols, and acids are organic carbon-containing natural compounds
that are produced by plant roots.
• In the rhizosphere, microbes convert a contaminant into a non-
toxic substance.
• In a process known as biodegradation, such microorganisms can digest dang
erous organic compounds such as fuels or solvents and break them down int
o harmless materials.
• It's successful at removing petroleum hydrocarbons.
• Example :
In the root zone of hybrid poplar trees, the number of beneficial bacteria incre
ased, which improved the breakdown of BTEX, an organic compound, in the
soil.

9. Phytoextraction
• The absorption of pollutants by plant roots and transport of these pollutants from roots to the abo
ve portion of plants by absorbing, concentrating, and precipitating the contaminants. Also known
as phytoaccumulation, phytoconcentration , and phytomining.
• It converts toxins from soils, sediments, or water into harvestable plant biomass using plants or al
gae.
• There are two methods for phytoextraction:
• Both natural and assisted
• Natural: as plants absorb toxins from the soil on their own.
• Assisted : To mobilize and accelerate contaminant uptake, chelating agents, microbes, and plant
hormones are used.
• Pb desorption from the soil matrix can be caused by a number of synthetic chelates.
• Metal toxins are picked up by plant roots from the soil and translocated to above
ground tissues such as shoots and leaves.
• The plants are harvested and securely disposed off after they have grown and absorbed the met
al contaminants by curing, ashing , or composting.

10. Cont...
• To pollution to appropriate standards, this p
rocedure is performed many times.
• Because of their tolerance for comparatively
high levels of pollutants, many places use h
yper accumulator plant types.
• The use of hyperaccumulators such as Thla
spi caerulescens, Brassica sp.
and Avena sp. accelerated the uptake of pol
lutants.
• EXAMPLE: Sunflower and Indian Mustard
were used to clean up a lead-contaminated
site in Detroit.

11. Rhizofiltration
• Adsorption of toxins in the solution covering the root region, either by adsorption or accumulation
into plant roots.
• Used to treat groundwater, surface water, and waste water.
• Plants are used to address groundwater rather than soil in this situation, as opposed to
phytoextraction.
• Example
1. Sunflower, Indian mustard, tobacco, rye, spinach, and corn have all been tested to see whether
they can extract lead from water, with sunflower showing the best results.
2. In a test at Chernobyl, Ukraine, sunflowers were successful in removing toxic pollutants from pond
water.
• Pb, Cd, Cu, Ni, Zn, and Cr, which are mostly stored within the roots, can be filtered using
rhizofiltration.

12. Cont...
1 . Plants are grown hydroponically in clean
water rather than soil until they have
established a broad root system.
2 . To acclimate the plant, a clean water source
is substituted for a contaminated water supply.
3. They are planted in contaminated areas,
where the roots consume polluted water as
well as pollutants.
4 . When the roots are saturated, they are
harvested and securely disposed off.

13. Phytostabilization
• This is also known as in place inactivation .
• Pollutants in the soil are immobilized by absorption and deposition by roots, as
well as precipitation within the roots.
• Eventually, the pollutants’ mobility is reduced, migration to groundwater is
stopped, and thus the metal's bioavailability in the food chain is lowered.
• Broad bare surfaces caused by mining activities or arial accumulation of metals
from metal smelters are known as Target Areas.
• Metal-tolerant plants may be used to help regenerate the vegetation on the sites.

14. Cont...
• It is mainly used for soil, sediment, and sludge
remediation.
• Used to reassert plant cover at locations where
natural vegetation has died due to elevated
metal concentrations in surface soils or physical
disturbances to surface materials.
• Example: At a Superfund site in Palmerton, PA,
phytostabilization using metal-tolerant grasses is
being tested for vast areas of Cd- and Zn-
contaminated soils.

15. Advantages Disadvantages
• When compared to other more
traditional approaches, it is more cost
effective.
• “Natural” approach is more aesthetically
pleasing.
• Land disruption is held to a minimum.
• Reduces the opportunity for toxins to be
transported by wind/soil erosion.
• Using the same herb, several chemicals
may be extracted.
• It is one of the safest methods available.
• The probability of precious metals being
recovered and reused.
• (Phyto mining)
• Decontamination takes a long time and
is difficult to reach appropriate
standards.
• Contaminated plants may make their
way through the food chain.
• Contaminant spread through dropping
leaves is a possibility.
• Plants and trees need treatment.
• Contaminant has the ability to destroy
the tree.
• The degradation agent can be more
toxic than the initial contaminant.
• Only the top layer of soil (the root zone)
can be treated.
• It will take some years to clear up the

16. Phytoremediation
example
Hydrangeas are well-known ornamental
plants that are cultivated for their large
flower clumps. Their other expertise is
that they are in charge of extracting
aluminum from the ground.
In bogs and wetlands, Water Hyssop
(Bacopa monnieri) extracts zinc, arsenic,
cadmium, and chromium.
Cadmium, zinc, and copper are also
consumed by Willow trees.

17. Water Hyacinth
• Water Hyacinth is a floating plant
with wide, thick, and shiny leaves
that can reach a height of 1 meter.
• It doubles population in two weeks
hence, known as one of the plants
with the fastest growth rates,
capable of phytoaccumulating
metal contaminants such as Ag,
Pb, Cd, and Zn in municipal and
agricultural wastewater.
• Invasive potential is high.

18. Duckweed
• Duckweed is a type of weed that
grows
• With a small plate-shaped structure
floating on the water surface, that
lacks visible roots or leaves.
• Asexual budding is the most
common method of reproduction.
• Because of its small scale, rapid
growth, and ease of cluture, it has a
high pollutant removal capacity.

19. Case Study: Removal of Cadmium by Duckweed
Cd removal efficiencies (Kara and Kara, 2004)
• Before beginning testing, the
duckweed collected from a natural
lake was acclimated to laboratory
conditions for one week.
• Cadmium solution was made using
Cd(NO3)2 and was in contact with
plant samples for varying periods of
time.
• Water samples were examined by
AAS at 228.8nm after absorption.
INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY 1560–8530/2005/07–4–660–662
Removal of Cadmium from Water Using Duckweed (Lemna trisulca L.)
YEŞIM KARA1 AND IZZET KARA†
Department of Biology, Faculty of Art and Sciences–20017, †Faculty of Education–20020, University of Pamukkale, Denizli-
Turkey

20. Thank you for
listening