This presentation is on the methods of Phytoremediation performed in Science, along with concrete examples.

1. Phytoremediation
Presented by:
- Bhagea Ritesh
- Buctowar Rouksaar
- Cécile Christabelle
- Ghoorbin Keshavi
- Nazeer Huda
Date: 14th March 2014

2. Contents
1. Pollution
2. Methods to reduce pollution
3. Phytoremediation - What is it?
4. Advantages and Disadvantages
5. Mechanisms/Processes
6. Examples of Phytoremediation
7. Types of plants used
8. Conclusion
9. References

3. Pollution and Pollutants

4. Pollution
● When harmful substances contaminate the natural
environment it is called Pollution.
● Intense industrial and agricultural activities worldwide.
● Pollutants such as Heavy metals (Hg and Ni),
Petroleum hydrocarbons and pesticides.
● Consequences:
- Disturbs ecosystem
- Global Warming
- Human health
- Infertile lands

5. Examples of Pollution

6. Oil and Water Pollution
http://totallycoolpix.com/2013/02/water-pollution-in-china/

7. Methods to reduce
pollution

8. Methods to reduce Pollution
● For treating soil contamination(metal), methods such as:
1. excavation,
2. thermal treatment,
3. acid leaching,
4. electro reclamation
● Water treatments involve
1. sedimentation,
2. thermal treatment with mechanical filtration

9. Methods to reduce Pollution
●Treatments are costly, not environmental friendly and
not very effective.
●Therefore, new techniques have been developed in
terms of bioremediation and among them is the
Phytoremediation.

10. Phytoremediation

11. Phytoremediation - What is it?
Definition: Use of green plants and their microorganisms to
reduce environmental problems without the need to excavate
the contaminant material and dispose of it elsewhere.
● Natural process - can be an effective remediation method
at a variety of sites and on numerous contaminants.
● Selected plant species possess the genetic potential to
remove, degrade, metabolize, or immobilize a wide range
of contaminants (~350 species).

12. Advantages and Disadvantages
of Phytoremediation

13. Advantages Disadvantages
In situ and ex situ Take several years to remediate a contaminated
site
Amenable to a variety of organic
and inorganic compounds
Limited to shallow groundwater, soils and
sediments
Suited to remediation of large areas
of soil
Not as effective for sites with high contaminant
concentrations
Costs effective compared to
conventional methods
Slower than conventional methods
Easy to implement and maintain &
accepted by public
Toxicity and bioavailability of biodegradation
products are not known
Fewer spread of contaminant via air
and water
Contaminants may be mobilized into the ground
water.
Conserves natural resources Influenced by soil and climate conditions of the
site. It does not work in the winter.
Environmentally friendly and
aesthetically pleasing to the public
Disposal of contaminants accumulated in plants
after harvesting - pollution again!

14. Mechanisms of
Phytoremediation

15. Mechanisms of Phytoremediation
● Depend on the types of contaminant, bioavailability and
soil properties.
● There are several ways by which plants clean up
contaminated sites.
● Uptake of contaminants occurs primarily in root system
large SA that absorbs and accumulates
water and nutrients essential for growth

16. Phytoremediation mechanisms
Phytoextraction
Phytostabilization
Phytoremediation Phytotransformation
Phytostimulation
Phytovolatilization
Rhizofiltration

17. Overview

18. 1. Phytoextraction
Definition: The uptake of contaminants by plant roots and
movement of these contaminants from roots to the
above part of plants - by absorbing, concentrating and
precipitating the contaminants.
http://www.biology-online.org/js/tiny_mce/plugins/imagemanager/files/boa001/phytoremediationf03.JPG

19. 1. Phytoextraction
Two ways for phytoextraction: Natural and
assisted
● Natural: where plants naturally take
up contaminants from the soil - unassisted
● Assisted: use of chelating agents,
microbes and plant hormones to mobilize
and accelerate contaminant uptake.
➔ Uptake of contaminants also accelerated
by use of hyperaccumulators
e.g Thlaspi caerulescens

20. 1. Phytoextraction
Advantages:
● Cost is fairly inexpensive
compared to conventional
methods.
● Contaminant permanently
removed from soil.
● Amount of waste material
that must be disposed of
is decreased up to 95%
● In some cases,
contaminant can be
recycled.
Limitations:
• Metal bioavailability within
the rhizosphere.
• Rate of metal uptake by
roots.
• Proportion of metal “fixed”
within the roots.
• Cellular tolerance to toxic
metals.

21. 2. Phytostabilization
Definition: Refers to the immobilization of contaminants in
the soil through:
○ absorption and accumulation by roots,
○ precipitation within the roots.
● Eventually, the mobility of the contaminant is reduced,
migration to groundwater is prevented and thus
bioavailability of metal into food chain is reduced.

22. 2. Phytostabilization
Advantages:
● No disposal of
hazardous material /
biomass is required
● Very effective when
rapid immobilization is
needed to preserve
ground and surface
waters
Disadvantages:
● Contaminant remain in
soil
● Application of extensive
fertilisation / soil
amendments
● Mandatory monitoring
required

23. 3.Phytotransformation
Definition: Also known as phytodegradation,
it is the breakdown of contaminants taken up
plants by metabolic processes within the
plant.
● Remediate some organic contaminants,
such as chlorinated solvents, herbicides,
and munitions
● It can address contaminants in soil,
sediment, or groundwater.

24. 3. Phytotransformation
Advantage:
● Both economically and
environmentally friendly
Disadvantages:
● Requires more than one
growing season to be
efficient
● Soil must be less than 3 ft
in depth and groundwater
within 10 ft of the surface
● Contaminants may still re-
enter the food chain
through animals or insects
that eat plant material

25. 4. Phytostimulation (Rhizodegradation)
Definition: Breakdown of
contaminants within the plant root
zone, or rhizosphere.
● Carried out by bacteria or other
microorganisms flourishing in
the rhizosphere.
● Microbes in rhizosphere
transform contaminant to non
toxic product.
● Works well in the removal of
petroleum hydrocarbons

26. 4. Phytostimulation
Advantages:
● in situ practice resulting
in no disturbance
● No removal of
contaminated materials
● Complete mineralisation
of the contaminant can
occur
● Low installation and
maintenance cost
Disadvantages:
● Development of extensive
root zone required- takes
time
● Root depth limited due to
physical structure of soil
● Organic matter from plant
may be used as a C
source instead of
contaminant -> decrease
amount of contaminant
biodegradation

27. 5. Phytovolatilization
Definition: Involves plants taking up contaminants from soil,
transforming them into volatile forms and transpiring them into
atmosphere
● Works on organic compounds and heavy metal
contaminants, TCE as well.
● Mercury is the primary metal
contaminant that this process has
been used for.

28. 5. Phytovolatilization
Advantage:
•The contaminant, mercuric
ion, may be transformed
into a less toxic substance
(i.e., elemental Hg).
Disadvantage:
•The mercury released into
the atmosphere is likely to
be recycled by precipitation
and then re-deposited back
into lakes and oceans,
repeating the production of
methyl-mercury by
anaerobic bacteria.

29. 6. Rhizofiltration
Definition: Adsorption or precipitation onto plant roots or
absorption of contaminants in the solution surrounding the
root zone.
● Used to remediate extracted groundwater, surface
water, and waste water with low contaminants.
● Compared to phytoextraction, here the plants are used
to address the groundwater rather than soil.

30. 6. Rhizofiltration
Advantages:
● Ability to use both
terrestrial and aquatic
plants for either in situ
and ex situ applications.
● Contaminants do not
have to be translocated
into shoots.
Disadvantages:
● Constant need to adjust
pH.
● Plants may first need to
be grown in greenhouse
/ nursery.
● There is periodic
harvesting and plant
disposal.
● Tank design should be
well engineered.

31. How long does phytoremediation
takes?
● The time depends on:
- Type and number of plants used
- Type and amount of harmful chemicals present
- Size and depth of polluted area
- Type of soil and conditions present
● Often, it takes many years to clean up a site
with phytoremediation.

32. What to do with plant containing
contaminants (metals)?
The shoot is harvested to recover the metal.

33. How the metals extracted be used again?

34. Types of plants used

35. Types of plant used
● Plant species are selected for use based on factors
such as:
- ability to extract or degrade the contaminants of
concern
- adaptation to local climates
- high biomass
- depth root structure
- compatibility with soils
- growth rate
- ease of planting and maintenance
- ability to take up large quantities of water through the
roots.

36. Types of plants used

37. Types of plants used
Hydrangeas are popular
ornamental plants grown
for their large clumps of
flowers. Their other
speciality is that they are
responsible for drawing
aluminium out of the soil.
Water Hyssop (Bacopa monnieri)
removes lead, mercury, cadmium
and chromium from bogs and
wetland.
Willow trees
absorb
cadmium,
zinc and
copper

38. Phytoremediation - e.g of Transgenic Plants
● Nicotiana tabaccum, expressing a yeast metallothionein
gene for higher tolerance to cadmium,
● Arabidopsis thaliana, overexpressing a mercuric ion
reductase gene for higher tolerance to mercury.

39. Examples of
Phytoremediation

40. Example of Rhizofiltration
● In 1995, Sunflowers were used in pond near
Chernobyl.
http://www.igece.org/WRKY/BrachyWRKY/WRKY/IMG/Rhizofiltration.jpg

41. Phytoremediation of heavy metals by
calcifying macro-algae
● Anthropogenic activities release heavy metals into water
bodies which can lead to imbalancement of the
ecosystem.
● To minimise such risk, phytoremediation comes into play.
● Plants,used as remediation techniques, take up the
heavy metals to produce an internal concentration
greater than that of the external environment.

42. ● A concern is raised about the fate of plants used.
- Regular harvesting is needed so that the plants do
not decompose releasing the accumulated
heavy metals back in the water.
- Research to identify plants that can store heavy metals
for a longer period of time/ plants that can transform
heavy metals to less bioavailable and immobile forms.
Phytoremediation of heavy metals by
calcifying macro-algae

44. Conclusion
● Although much remains to be studied,
phytoremediation will clearly play some role in the
stabilisation and remediation of many contaminated
sites.
● The main factor driving the implementation of
phytoremediation projects are low costs with
significant improvements in site aesthetics and the
potential for ecosystem restoration.

45. References

46. 1. Donn, J. (2001). Fern will detoxify soil - Fern a possible toxic waste cure, pp 8A.
In newspaper: Rome News - Tribute.
http://news.google.com/newspapers?
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2. Etim, E.E. (2012). Phytoremediation and its mechanisms: A review. International
Journal of Environmental and Bioenergy 2(3), 120 - 136.
http://modernscientificpress.com/Journals/ViewArticle.aspx?
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[Date acccessed: 09/03/2014]
3. Flash demo on phytoremediation-https://illumin.usc.
edu/printer/80/phytoremediation/ [Date accessed: 12/03/2014]
4. Mishra, C.S,K. (2007). Rhizoremediation - An Emerging Technology for
Management of Environmental Pollutants. In: Environmental Biotechnology, pp
209-223. Balaji Offset.
http://books.google.mu/books?
id=YN0ZNmraDDMC&printsec=frontcover#v=onepage&q&f=false [Date
accessed: 12/03/14]

47. 5. Nordlander, H. (2012). Comparative assessment of rhizodegradation
approachment to PAHs pollution. International Summer Water Resources
Research School. Dept. of Water Resources Engineering, Lund University.
Published online.
http://www.tvrl.lth.
se/fileadmin/tvrl/files/vvrf05/HannaN_Comparative_assessment_of_rhizodegradati
on_approaches_to_PAHs_pollution.pdf [Date accessed: 12/03/2014]
6. Phytoremediation ppt on slideshare http://www.igece.
org/WRKY/BrachyWRKY/WRKY/IMG/Rhizofiltration.jpg [Date accessed: 12/03/14]
7. Poisoned River - Gold Mining Along the Biliu River, 20111117, Pacific
Environment http://www.habitatadvocate.com.au/?tag=china-water-pollution[Date
accessed: 09/03/2014]
8. Tann, N. (2012) 26 years later: Remembering the Chernobyl Nuclear Disaster.
Websire: The Batimore Sun http://darkroom.baltimoresun.
com/2012/04/remembering-chernobyl/#30 [Date accessed: 09/03/2014]

48. 10. Text by Price, J. and Dare, S.
http://homeopathtyler.wordpress.com/2010/06/18/phyto-remediation-using-
plants-to-remove-toxins/ [Date accessed: 12/03/2014]
11. University of Hawaii - Department of Bioremediation Technologies
http://www.hawaii.edu/abrp/Technologies/phytran.html [Date accessed:
09/03/2014]
12. http://www.slideshare.net/nmanthreege/phytoremediation-11602480?
qid=4c84753a-f99a-4cd6-b9b4-32e743e03526&v=default&b=&from_search=2
[Date accessed: 12/03/14]
13. http://totallycoolpix.com/2013/02/water-pollution-in-china/ [Date accessed:
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14. http://deoracle.org/learning-objects/phytoremediation.html [Date accessed:
12/03/2014]

49. Any questions?