1. Elizabeth Pilon-Smits
BZ572 - Phytoremediation
Elizabeth Pilon-Smits
Biology Department
E413 ANAZO

3. Let’s hear from you Please write on piece of paper:
Degree, major/department, reg./auditing?
What is your career goal?
How does phytoremediation fit in?
Any particular aspects of phytoremediation
you are most interested in?

4. BZ572 – Course Info Text: No book, only papers from course website
webct
Text:
No book, only papers from course website
Topics:
Intro to phytoremediation
Phyto of inorganics*)
Phyto of organics*)
1 Lab expt, 1 trip to a lab, 1 field trip (if interest),
5 guest lectures, in-class exercises, job info
*) mechanisms of uptake, translocation, detoxification,
effects of soil, microbes on remediation, approaches to enhance phyto efficiency, including genetic engineering

5. Grading: Conventional, no curving
Exams: 50% of total grade
- 1 midterm + 1 final exam (not comprehensive)
essay questions
Term paper & presentation: 30% of grade
write web page/proposal/review + present
In-class participation: 20% of grade
lab report, in-class group assignments, literature discussions

6. Introduction to Phytoremediation
History
Status
Uses
Advantages
Limitations
Phytoremediation strategies

7. History of phytoremediation
for centuries: wetlands used for
waste treatment in Europe
last century: metal hyperaccumulator
plants discovered - used as indicators for mining
1970s: - clean water act, clean air act
1980s:
- superfund act ( billion $)
- idea to use hyperaccumulator
plants for metal cleanup (Chaney)

8. History of phytoremediation (cont.)
1994: phytoremediation term coined
(Ilya Raskin)
massive interest from gov. & industry
- DOE phytorem. workshop
- first phytorem. company (Phytotech)
1995: first phytorem. conference
phytoremediation takes off

9. History of phytoremediation (cont.)
(Raskin)
1994: Term phytoremediation first used
1995: First phyto conference
Columbia MO
2000: EPA phyto conference
2000: 1st phyto faculty positions
2000: 1st phyto course (this one)
2001, 2003: 1st, 2nd phyto call for proposals
(NSF/EPA/DOE)
2000, 2001: 1st, 2nd professors in phyto
(U Mich, U S-Carolina)

10. Status of phytoremediation
U.S. phytoremediation market
(Glass, 1999, 2004 pers. comm.)
1999 $ million / yr
2004 $ million / yr
World phytoremediation market
1999 $ million
Total remediation market
US: $ 6-8 billion/yr
World: $ billion/yr

11. Status of phytoremediation (cont.)
9 purely phytorem. companies
7 constructed wetland companies
> 40 consulting/engin. companies
that also do phytoremediation
~200 field projects
- funded mostly by EPA, DOD, DOE
- some commercial/joint projects

12. Uses of phytoremediation
Remediation of different media:
air
soils, sediments
groundwater
wastewater streams
- industrial
- agricultural
- municipal, sewage

13. Uses of phytoremediation (cont.)
Remediation of different pollutants:
organics:
- PCBs
- PAHs
- TCE
TNT
MTBE
- pesticides
- petroleum
hydrocarbons
Etc.
inorganics:
- metals (Pb, Cd, Zn, Cr, Hg)
- metalloids (Se, As)
- “nutrients” (K, P, N, S)
- radionuclides (Cs, U)

14. Uses of phytoremediation (cont.)
Remediation using different systems:
farming polluted soil
irrigation with polluted groundwater
letting trees tap into groundwater
letting plants filter water streams
constructed wetlands, hydroponics

15. different systems:
Hydraulic barrier

16. different systems:
Vegetative cap

17. different systems:
Constructed wetlands

18. different systems:
hydroponics with polluted wastewater

19. Acting as filters for heavy metals
There is important research being done by CSU personnel under the direction of Dr. Duane Johnson and Dr. Leanne Pilon-Smits to find the species of plants that will be the most effective in filtering out the zinc, magnesium, cadmium, and lead in the effluent. Plants such as mustard, canola, barley (in the background), and quinoa are being tested for their effectiveness. Transgenic mustards, that have genes which limit absorption of heavy metals by plants, may allow for greater up-take (beyond toxic levels) of heavy metals.
Roots of mustard
Extend into effluent
Acting as filters for heavy metals

20. Uses of phytoremediation (cont.)
Remediation using different plants
Properties of a good phytoremediator:
high tolerance to the pollutants
high biomass production, fast growth
large, deep root system
good accumulator/degrader of pollutant
able to compete with other species
economic value

21. Popular plants for phytoremediation
Uses of phytoremediation (cont.)
Popular plants for phytoremediation
trees
various organics
metals
gum tree
poplar
yellow poplar
willow

22. Brassicaceae: grasses For inorganics Thlaspi Alyssum Brassica juncea
Uses of phytoremediation (cont.)
Popular plants for phytoremediation
(cont.):
Brassicaceae:
grasses
For inorganics
Thlaspi
Alyssum
Brassica juncea

23. various grasses for organics hemp for inorganics kenaf bamboo
Uses of phytoremediation (cont.)
Popular plants for phytoremediation
(cont.):
various grasses
for organics
hemp
buffalo grass
red fescue
for inorganics
kenaf
bamboo

24. aquatic plants halophytes for inorganics for organics
Uses of phytoremediation (cont.)
Popular plants for phytoremediation
salicornia
aquatic plants
cattail
parrot feather
halophytes
for inorganics
for organics
reed
poplar, willow
spartina

25. Advantages & Limitations
of Phytoremediation

26. Mechanical/chemical treatment
Phytoremediation
In situ
Solar energy
Fossil fuels for energy
Ex situ
Mechanical/chemical treatment
Soil washing
Excavation + reburial
Chemical cleanup of soil/water
Combustion

27. Advantages of phytoremediation
Phytoremediation vs.
Mechanical/chemical treatment
Advantages of phytoremediation
~ x
Cheaper
Excavation & reburial: up to $1 million/acre
Revegetation: ~$20,000/acre

28. Mechanical/chemical treatment
Phytoremediation vs.
Mechanical/chemical treatment
Advantages of phytoremediation (cont.)
Less intrusive
Can be more permanent solution
Better public acceptance

29. Limitations of phytoremediation
Phytoremediation vs.
Mechanical/chemical treatment (cont.)
Limitations of phytoremediation
Can be slower
Limited by rate of biological processes
Accumulation in plant tissue: slow
e.g. metals: average 15 yrs to clean up site
- Filter action by plants: fast (days)
- Metabolic breakdown (organics): fairly fast
(< 1yr)

30. Mechanical/chemical treatment (cont.)
Phytoremediation vs.
Mechanical/chemical treatment (cont.)
Limitations of phytoremediation (cont.)
Limited root depth
Trees > prairie grasses > forbs, other grasses
Max depth ~5 m
Can be increased
up to 20m with
“deep planting”

31. Mechanical/chemical treatment (cont.)
Phytoremediation vs.
Mechanical/chemical treatment (cont.)
Limitations of phytoremediation (cont.)
Plant tolerance to pollutant/conditions
- Bigger problem with metals than organics
- Can be alleviated using amendments, or treating hot spots by other method
Bioavailability of contaminant
- Bioavailability can be enhanced by amendments

32. So, when choose phytoremediation?
Sufficient time available
Pollution shallow enough
Pollutant concentrations not phytotoxic
$$ limited
Note: Phyto may be used in conjunction with
other remediation methods
For very large quantities of mildly
contaminated substrate:
phytoremediation only cost-effective option

33. Phytoremediation processes

34. Phytoremediation processes
phytostabilization

35. pollutant immobilized in soil
Phytostabilization:
pollutant immobilized in soil
- Metals
- Non-bioavailable organics
Plants reduce leaching, erosion, runoff
 pollutant stays in place
2. Plants + microbes may transform pollutant
to less bioavailable form
(e.g. metal precipitation on roots)

36. Phytoremediation processes
phytostimulation

37. Phytostimulation: plant roots stimulate degradation of pollutant
by rhizosphere microbes
Organics
e.g. PCBs, PAHs
bacteria, fungi

38. Phytoremediation processes
phytodegradation

39. plants degrade pollutant, with/without uptake, translocation
Phytodegradation:
plants degrade pollutant,
with/without uptake, translocation
Via enzymes,
e.g. oxygenases
nitroreductase
in tissues or
in root exudate
Certain organics
e.g. TCE, TNT, atrazine

40. Phytoremediation processes
phytoextraction
accumulation

41. Phytoextraction: pollutant accumulated in harvestable plant tissues
mainly inorganics:
metals
metalloids
radionuclides
Plant biomass may be used
(e.g. to mine metals, or non-food industrial use)
or disposed after minimizing volume
(incineration, composting)

42. Phytoremediation processes
phytovolatilization

43. Phytovolatilization: pollutant released
in volatile form into the air
some metal(loid)s: Se, As, Hg
some volatile organics: TCE, MTBE

44. Phytoremediation applications may involve multiple processes at once
accumulation
volatilization
stabilization
degradation

45. Rhizofiltration
water

46. Rhizofiltration: pollutant removed from
water by plant roots in hydroponic system
for inorganics
Plant roots & shoots harvestable
(may be used to mine metals)
or disposed after minimizing volume
metals
metalloids
radionuclides

47. Hydroponics for metal remediation:
75% of metals removed from mine drainage
Rhizofiltration
Involves:
phytoextraction
phytostabilization

48. Constructed wetland for Se remediation:
75% of Se removed from ag drainage water
Involves:
phytoextraction
phytovolatilization
phytostabilization
(rhizofiltration)
(phytostimulation)

49. Natural attenuation: polluted site left alone
but monitored
Vegetative cap: polluted site revegetated,
then left alone, monitored
with/without
adding
clean topsoil

50. Hydraulic barrier
Water flow redirected
Pollutants intercepted
H2O

51. Phytoremediation project (1996-)
(Phytokinetics inc.)
Oregon site
Soil polluted with PAHs
Planted with grass (Lolium perenne)
Results:
bare soil: some PAH removal
vegetated soil: increased PAH removal (~4x)
Process?
Phytostimulation/phytodegradation

52. Phytoremediation project (1995-1998)
(Phytotech inc.)
New Jersey site
Soil polluted with lead (Pb)
Planted with Indian mustard (Brassica juncea)
Results (after 3 growing seasons):
bare soil: 6% reduction in Pb
vegetated soil: 29% reduction in Pb
Process?
Phytoextraction

53. Phytoremediation project (1997)
(COE)
Mississippi site
Groundwater polluted with TNT
pumped through constructed wetland
Results:
95% reduction in TNT
endogenous plant enzymes found to
degrade TNT
Process?
Phytodegradation

54. Print from Course Website EPA: Citizen’s guide to Phytoremediation
Some light reading:
Print from Course Website
EPA: Citizen’s guide to Phytoremediation
EPA: Citizen’s guide to Natural Attenuation
Pilon-Smits, 2005
Phytoremediation (review)
Ann Rev Plant Biology