ESM 217

1
ESM 217

• l. Phytoremediation
• ll.Biomanipulation

2
Phytoremediation

• Phytoremediation is a process that uses plants to
  remove, transfer, stabilize, or destroy
  contaminants in soil, sediment, and groundwater

3
Phytoremediation
4
Phytoremediation

• Applies to all biological, chemical, and physical
  processes that are influenced by plants
  (including the rhizosphere) and that aid in
  cleanup of the contaminated substances
• Plants can be used in site remediation, both
  through the mineralization of toxic organic
  compounds and through the accumulation and
  concentration of heavy metals and other inorganic
  compounds from soil into aboveground shoots
• Phytoremediation may be applied in situ or ex
  situ, to soils, sludges, sediments, other solids,
  or groundwater.

5
Mechanisms

• Phytoextraction the uptake of contaminants by
  plant roots and the translocation/accumulation of
  contaminants into plant shoots and leaves

• Used to treat soil, sediments, sludge, and
  contaminated water
• Good for Ag, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and
  Zn
• Plants indian mustard, sunflower, tabacco
• Advantages plant biomass with contaminant
  extracted contaminant can be a resource
  elsewhere often cheaper than extraction
  (excavation, washing, incineration)
• Disadvantages metals hyperaccumulators often
  grow slowly small biomass shallow root system
  metal reclamation and disposal costly
• Thalspi rotundifolium in Pb-Zn mine area 0.82
  Pb, 1.73 Zn.

6
Mechanisms

• Phytoextraction

7
Mechanisms

• rhizosphere biodegradation breakdown of an
  organic contaminant in soil through microbial
  activity enhanced by the root zone. Takes place
  in soil or groundwater immediately surrounding
  plant roots

• Used to treat soil, sediments, sludge, and
  contaminated water
• Good for PAHs, TPH, pesticides, herbicides, BTEX
• Plants red mulberry, crab apple, spearmint,
  rice, bush bean
• Advantages in situ destruction of contaminants,
  mineralization tightly binds, cheap.
• Disadvantages development of root system slow,
  root depth limited by physical barriers, may need
  fertilization

8
Mechanisms

• rhizosphere biodegradation

9
Mechanisms
Phytodegradation, the metabolism of contaminants
within plant tissues

• Used to treat soil, sediments, sludge, and
  contaminated water
• Good for chlorinated solvents, herbicides,
  insecticides, munitions (TNT)
• Plants parrot feather and stonewort (aquatic),
  poplar, back willow, live oak
• Advantages in situ sequestration of
  contaminants, mineralization tightly binds,
  cheap.
• Disadvantages plant growth rate may limit
  utility, may have to dispose of plants before
  bioaccumulated by grazers, may need fertilization

10
Mechanisms
Phytodegradation

• Metabolism within plant
• Production of the dehalogenase
• and oxygenase enzymes,
• catalyzes degradation

Contaminant uptake
11
Mechanisms

• Rhizofiltration adsorption or precipitation onto
  plant roots, or adsorption into roots of
  contaminants that are in solution surrounding the
  root zone due to biotic or abiotic processes.

• Used to treat soil, sediments, sludge, and
  contaminated water
• Good for Pb, Cd, Cr, Ur, Cu, Ni, Sr
• Plants red mulberry, crab apple, spearmint,
  rice, bush bean
• Advantages in situ sequestration of
  contaminants, mineralization tightly binds
  chemicals, cheap.
• Disadvantages development of root system slow,
  root depth limited by physical barriers, may need
  fertilization
• Pilot-scale projects only

12
Mechanisms

• Phytostabilization immobilization of
  contaminated soil through absorption and
  accumulation by roots, adsorption on to roots, or
  precipitation within root zone, or use of plant
  roots or plant to prevent migration via wind,
  water, erosion, leaching, soil dispersion

• Used to treat soil, sediments, sludge
• Good for Zn, Pb, Cu, Cr, Cd
• Plants metal tolerant spp red fescue, bentgrass
• Advantages soil removal is unnecessary lower
  cost and less disruptive than other soil
  remediation technologies- washing, leaching
  disposal of hazardous material or biomass not
  necessary cheap ecosystem restoration possible
• Disadvantages contaminants remain in place-
  long-term maintenance fertilization soil
  modification must prevent above ground movement

13
Mechanisms

• Phytovolatization uptake and transportation of a
  contaminant by a plant, with releases of
  contaminant or modified form to the atmosphere
  

• Used to treat ground water, soil, sediments,
  sludge
• Good for Hg, Se, TCE, CTC
• Plants Poplars, alfalfa, indian mustard
• Advantages contaminants transferred to less
  toxic forms.
• Disadvantages hazardous materials can be
  released as gas stored in plant uptaken by
  grazers

14
Mechanisms

• Phytovolatization

15
Mechanisms

• Hydraulic control

Poplars and cottonwoods
16
Mechanisms

• Vegetation cover

17
Mechanisms

• Vegetation cover

18
Mechanisms

• Riparian corridors/buffer strips generally
  applied along streams, rivers banks, wetland
  edges to control and remediate surface runoff and
  groundwater contamination moving into water body
  

• Used to treat surface and ground water runoff
• Good for water borne contaminants and nutrients
• Plants Poplars, wetland plants (Spartina spp.),
  water uptake and plant metabolism incorporates
  hydraulic control, phytodegradation,
  rhizodegradation, phtyovolatization, and
  phytoextraction
• Advantages stabilizes banks, creates habitat
• Disadvantages hazardous materials can be
  released as gas stored in plant uptaken by
  grazers

19
Mechanisms

• Riparian corridors/buffer strips

20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Limitations of phytoremediation?

• Population level the plant
• Community level- species interactions
• Landscape levels- climate

24
http//www.clu-in.org/download/remed/introphyto.pd
f
25
ll. Biomanipulation
26
Biomanipulation in northern lakes

• Trophic cascade

Historically normal food web
Piscivores
planktivores
herbivores
phytoplankton
PO4
nutrients
27
Biomanipulation in northern lakes
planktivores
Modern food web
herbivores
phytoplankton
PO4
nutrients
28
Biomanipulation in northern lakes
Some lakes restocked
Piscivores
planktivores
herbivores
phytoplankton
PO4
nutrients
29
Biomanipulation in northern lakes
Biomanipulation restock eutrophied lakes with
piscivores
PO4
30
Other examples?