PHYTOREMEDIATIONCONCEPTS AND
TECHNIQUESName: A. Ranga RaniID.NO:TAM-13-24
Phytoremediation
It is applied at sites with contamination of
Organic Chemicals –TCE, TNT,, PCBs etc Nutrient – Ammonia, Phosphate, Nitrate Metal pollutants – Lead, Cadmium, Zinc,
Arsenic, Chromium
Phytoremediation is a process that uses plants to remove, transfer, stabilize, and destroy contaminants in soil and sediment.
Pteris vittata
Brassica juncea
Thlaspi caerulescens
Alyssum serpyllifoliumHyperaccumulator plants
Poplar sps
PHYTOSTIMULATION
Phytoextraction
It is the uptake of contaminants,particularly toxic metals and radio
nuclei by plant roots and the translocate to the above ground parts.
Specially selected plants, known as hyperaccumulators, can extract and
accumulate exceptionally high levels of contaminants from soil.
Phytoextraction is achieved by two methods:
1. Continuous phytoextraction
2. Induced phytoextraction
1. Continuous phytoextraction
It is based on the phytological processes that allow plants
to accumulate metals over the complete growth cycle. It is
based on the genetic and physiological capacity of hyper
accumulators to accumulate,translocate and resist high
amount of metals
• The first hyper accumulators characterized were number of Brasicaceae. Eg: Thallium- Iberis intermedia and Biscutella laevigata of brassicaceae family,
• Zn in roots and shoots of Thalaspi arvense
• Brassica juncea in Pb, Zn and Cd
Chinese brake fern, P. vittata to hyperaccumulate arsenic
Remediation of saline soils
Salicornia (pickleweed) accumulates salt in vacuole.A form of table salt can then be extracted from plant.
Induced phytoextraction
• It is also known as chelate assisted phytoextraction. Synthetic
metal chelates such as EDTA addition to soil increase the heavy
metal accumulation by plants.
• Metal accumulation efficiency of plants is directly related to the
affinity of chelates for a particular metal.
• Eg. EDTA for Pb,Cd and citrate for U is normally recommended for
induced phytoextraction.
• Chelates applied at 5 and 10 mmol/kg to soil
Phytostabilization
Phytostabilization, also referred to as in place inactivation, is
primarily used for the remediation of soil, sediment, and
sludges
It is the use of plant roots to limit contaminant mobility and
bioavailability in the soil.
It is useful for the treatment of Pb as well as As, Cd, Cr, Cu
and Zn.
It is very effective when rapid immobilization is needed to
preserve ground and surface waters
Phytostabilization of mercury by willow roots
Yaodong Wang, 2004
Rhizofiltration
Rhizofiltration is primarily used to remediate extracted
groundwater, surface water, and wastewater with low contaminant
concentrations (Ensley, 2000).
It is defined as the filtering of water through a mass of roots to
remove toxic substances or excess nutrients.
Rhizofiltration can be used for Pb, Cd, Cu, Ni, Zn, and Cr, which
are primarily retained within the roots
Indian mustard
water hyacinthDuckweed (Lemna)
Azolla
Sunflower
Removal of substances from the
soil or water with release into the
air, possibly after degradation.
Indian mustard and canola
(Brassicanapus) may be effective
for phytovolatilization of
Selenium.
Enhancement of microbial activity for the degradation
of contaminants, typically around plant roots
PGPR bacteria produce heavy metal chelating agents
such as siderophores which results in sequestration of
metals and thus facilitates better crop growth in
polluted environment
Phytostimulation
PHYTOTRANSFORMATION
Uptake of substances from the environment, and
degradation occurring in the plant
Trichloroethylene (TCE), a prevalent groundwater
contaminant, transformed to less toxic
metabolites by using hybrid poplar tree
Phytoremediation of pesticides by a notorious pest plant
. This plant might be utilized as an efficient, economical and ecological alternative to accelerate the removal and degradation of agro-industrial wastewater polluted with ethion.
Cost effective when compared to other more conventional
methods.
“Nature” method, more aesthetically pleasing.
Minimal land disturbance.
Reduces potential for transport of contaminants by wind,
reduces soil erosion
Multiple contaminants can be removed with the same plant.
Disadvantages Success is dependant on the tolerance of the
plant to the pollutant Long length of time is required for remediation Possibility of contaminated plants entering the food
chain. Depends on the climate. Possible spread of contaminant through falling leaves.
THANK
YOU
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