BY

HUZAIFA UMAR

STUDENT NO: 20142894

Dept. 0f Biogineering

Cyprus international university26th December, 2014

Phytoremediation: An Overview

Methods of Phytoremdiation

Phytoaccumulation/Phytoextraction

Versions of Phytoaccumulation

Advantages and Disadvantages of Phytoaccumulation

Heavy Metals and Biological Systems

Process of Phytoaccumulation

Quantification of Phytoaccumulation Efficiancy

Conclusion

Soil contamination with heavy metals has been aserious worldwide problem, leading to economiclosses in agriculture and health problems in humans.

Phytoremediation is a bioremediation process thatuses various plants to remove, transfer, stabilizeand/or destroy contaminants in the soil and groundwater.

Phytoremediation is an integrated multidisciplinaryapproach to the cleanup of contaminated soils, whichcombines the disciplines of plant physiology, soilchemistry, and soil microbiology. And is a costefficient and environmentally compatible process thatuses plants to remove heavy metal from theenvironment by uptake, accumulation ortransformation of these metals in vegetal biomass(McCutcheon and Schnoor, 2003).

Uptake of contaminants bythe plant.

The plant accumulate thecontaminants into the rootsand above ground shoot orleaves.

Saves tremendousremediation cost byaccumulating low levels ofcontaminant from a widesspread area.

Phytoextraction (or phytoaccumulation) uses plants or algae toremove contaminants from soils, sediments or water intoharvestable plant biomass (organisms that take larger-than-normal amounts of contaminants from the soil are calledhyperaccumulators).

Phytoextraction has been growing rapidly in popularityworldwide for the last twenty years or so.

In general, this process has been tried more often forextracting heavy metals than for organics.

A living plant may continue to absorb contaminants until it isharvested. After harvest, a lower level of the contaminant willremain in the soil, so the growth/harvest cycle must usually berepeated through several crops to achieve a significant cleanup.

Selenium by Bassia Scoperia Cadmium by Salix Viminalis

Zinc by Thlaspi Caerulescens

Plant species Metal Metal accumulation

(mg kg−1

)

Reference

Alyssum bertolonii Ni 10 900 Li et al. (2003)

Azolla pinnata Cd 740 Rai (2008)

Corrigiola telephiifolia As 2110 (Garcia-Salgado et al., 2012)

Eleocharis acicularis Cu 20 200 Sakakibara et al. (2011)

Zn 11 200

Cd 239

As 1470

Euphorbia cheiradenia Pb 1138 Chehregani and Malayeri

(2007)

Pteris vittata As 8331 Kalve et al. (2011)

Cr 20 675 Kalve et al. (2011)

Schima superba Mn 62412.3 Yang et al. (2008)

Thlaspi caerulescens Cd 263 Lombi et al. (2001)

Natural hyper-accumulation:Where plants naturally take up thecontaminants in soil unassisted.

Induced or assisted hyper-accumulation: Where aconditioning fluid containing achelator or another agent isadded to soil to increase metalsolubility or mobilization so thatthe plants can absorb them moreeasily. In many cases naturalhyperaccumulators aremetallophyte plants that cantolerate and incorporate highlevels of toxic metals.

Advantages of Phytoextraction

Phytoextraction is environmental

friendliness.

Traditional methods that are usedfor cleaning up heavy metal-contaminated soil, disrupt soilstructure and reduce soilproductivity, whereasphytoextraction can clean up thesoil without causing any kind ofharm to soil quality.

Phytoextraction is less expensivethan any other clean-up process.

Disadvantages of Phytoextraction

It is controlled by plants.

It takes more time than anthropogenicsoil clean-up methods.

Beryllium(Be) and Aluminium (Al), although light metals, are sometimes counted as heavy metals in view of their toxicity (Volesky, 1990; Park, 2013).

Contamination Source

Common sources are from mining and industrial wastes; vehicle emissions;lead-acid batteries; fertilizers, paints and treated woods. Lead is the mostprevalent heavy metal contaminant (Di Maio, 2001),

Heavy metals enter plant, animal and human tissuesvia air inhalation, diet and manual handling.

Water sources (groundwater, lakes, streams andrivers) can be polluted by heavy metals leaching fromindustrial and consumer waste.

Plants are exposed to heavy metals through theuptake of water; animals eat these plants; ingestionof plant- and animal-based foods are the largestsources of heavy metals in humans (Radojevic andBashkin, 1999).

They can be a major problem for any biological organism as they may be reactive with a number of chemicals essential to biological processes (Lanids, Sofied and Yu, 2000).

They can also break apart other molecules into even more reactive species (such as: Reactive Oxygen Species) which will also disrupt biological processes.

Non-hyperaccumulators also absorb some concentration of heavy metals, as many heavy metals are chemically similar to other metals that are essential to the plants life.

1. Dissolution: The metal needs to be dissolved in something (as an ion in solution), so that, the plant roots can absorb (Misra et al., 2009).

2. Root absortion: The plant needs to absorb the metal from the root cell wall to the root (Clemes et al., 2002)

3. Root-to-shoot transport: The Plants need to chelate the metal in order to both protect itself and make the metal mobile (Rascio, 2011).

4. Storage:The plant moves the chelated metal to a place to safely store it.

5. Adaptation: Finally, the plant must adapt to any damages the metals cause during transportation and storage.

The efficiency of phytoextraction can be quantified by calculatingBioconcentration Factor and Translocation Factor:

BCF= Charvestedtissue /Csoil

Where Cht/= Conc. of metal (plant) and C soil = Con of Metal (soil).

TF = Cshoot /Croot

And TF indicates the efficiency of the plants in translocating theaccumulated metal from roots-shoots (Padmavathiamma & Li,2007).

Accumulation factor (A) % = Cplan tissue/Csoil X 100 (Wilson and Pyatt,2007).

Both BCF and TF are important in screening hyperaccumulators forphytoextraction of heavy metals (Wu et al., 2011)

Phytoaccumulation is simply the uptake of chemicals by plant.

The chemicals are heavy meatals (Hg, CU, Cr, Cd, Se etc)Example, Lead contaminated site can be remove usingSunflower and Indian Mustard.

Heavy metal accumulated plant Harvest Combustion Safe Disposal inspecialise dump/Biorecovery of precious metal

Versions of phytoaccumulation are: Natural hyper-accumulation and Induced or assisted hyper-accumulation.

Process of phytoaccumulation are: Dissolution; RootAbsorbtion ; Root-to-shoot-transport; Storage; Adaptation

Physical and chemical methods for clean-up andrestoration of heavy metal-contaminated soilshave serious limitations like high cost,irreversible changes in soil properties,destruction of native soil microflora and creationof secondary pollution problems. In contrast,phytoremediation is a better solution to theproblem and is environment-friendly andecologically responsible solar-driven technologywith good public acceptance.

1. Clemens S., Palmgren M.G. & Krämer U. (2002) A long way ahead: understanding and engineering plant metal accumulation. Trends in Plant Science 7, 309–315.

2. Landis WG, Sofield RM & Yu M-H 2000, Introduction to Environmental Toxicology: Molecular Substructures to Ecological Landscapes, 4th ed., CRC Press, Boca Raton, Florida, ISBN 9781439804100

3. McCutcheon, S.C., Schnoor, J.L. (Eds.), 2003. Phytoremediation: Transformation and Control of Contaminants.

4. Misra V., Tiwari A., Shukla B. & Seth C.S. (2009). Effects of soil amendments on the bioavailability of heavy metals from zinc mine tailings. Environmental

Monitoring Assessment 155, 467–475.5. Padmavathiamma P.K., L.Y. Li., (2007). Phytoremediation technology: hyper-

accumulation metals in plants. Water Air Soil Pollut., 184 (2007), pp. 105–1266. Rascio, N., and F. Navari-Izzo. (2011) "Heavy Metal Hyper-accumulating Plants:

How and Why do they do it? and what Makes them so Interesting?" Plant Science 180.2: 169-81. SCOPUS. Web. 16 October 2011

7. Radojevic M & Bashkin VN 1999, Practical Environmental Analysis, Royal Society of Chemistry, Cambridge, ISBN 0854045945

8. Wu, Q., S. Wang, P. Thangavel, Q. Li, H. Zheng, J. Bai, R. Qiu, (2011). Phytostabilization potential of Jatropha curcas L. in polymetallic acid mine tailings. Int. J. Phytorem., 13 (2011), pp. 788–804

THANK YOUTEŞEKKÜR EDERIM

شكرا إلصغائكمСпасибоNAGODE

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