University of Salahaddin College of Education Environmental science department

Phytoremediation

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Halala Rahman Qadir M.Sc. Plant physiology

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What is Phytoremediation?

• Phytoremediation : The process of removing contamination from soil or water using plants.

• phyto = plant• remedium = restoring balance.

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Phytoremediation

Phytoremediation consists of mitigating pollutant concentrations in contaminated soils, water, or air, with plants able to contain, degrade, or eliminate metals, pesticides, solvents,explosives, crude oil and its derivatives, and various other contaminants from the media that contain them.

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Advantages of plants:

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Phytoremediation is cost effectiveIt is suited to remediation of large areas of soil.

It is environmentally friendly.Phytoremediation sites are more aesthetically

pleasingPhytoremediation sites are low maintenance.It involves no noisy and expensive equipment

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DisadvantagesPhytoremediation is limited to sites with lower contaminant concentrations. Toremediation is restricted to sites with contamination as deep as the roots of the plants being used.Not as effective for sites with high contaminant concentrationsPhytoremediation is slower than conventional methodsIt does not work through the winter (Seasonally effective)

The food chain could be adversely affected by the degradation of chemicals.The air could be contaminated by the burning of leaves or limbs of plants containing dangerous chemicals.

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Phytoremediation

The most important single act of phytoremediation?

6 CO2 + 6 H2O C6H12O6 + 6 O2

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How Does Phytoremediation Work?

Plant roots take contaminants from the ground into the "body" of the plant. The plant root zone is referred to as the rhizosphere, this is where the action occurs.

This soil supports large populations of diverse microorganisms. This is due to chemicals exuded by plant roots which provide carbon and energy for microbial growth. This combination of plants and microorganisms appears to increase the biodegradation of compounds.

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This graphic shows a typical process diagram of phytoremediation.

Heavy metalsArsenicCadmiumLeadAluminumBerylliumCopperIronMercuryNickel

These persist in soils and are toxic to animals even in small quantities

Various phytoremdiation processes1. Phytoextraction or phytoconcentration, where

the contaminant is concentrated in the roots,stem and foliage of the plant,

2. Phytodegradation, where plant enzymes help catalyze breakdown of the contaminantmolecule,

3. Rhizosphere biodegradation, where plant roots release nutrients to microorganisms which are active in biodegradation of the contaminant molecule,

4. Volatilization, where transpiration of organics, selenium and mercury run through leaves of the plant,

5. Stabilization, where the plant converts the contaminant into a form which is not bioavailable, or the plant prevents the spreading of a contaminant plume.

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phytoremdiationPlants used to decontaminate soils must do one or more of

the following:• Take up contaminants from soil particles and/or soil liquid

into their roots,• Bind the contaminant into their root tissue, physically

and/or chemically,• Transport the contaminant from their roots into growing

shoots,• Prevent or inhibit the contaminant from leaching out of

the soil.

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Types of Vegetation Used

Some of the plants used in phytoremediation are:•Alfalfa•Hybrid Poplar Trees•Blue-green Algae•Arrowroot•Sudan Grass•Rye Grass•Duck Weed•Bermuda Grass•Alpine Bluegrass•Yellow or White Water Lillies

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