A1304539646_21901_25_2017_BIOREMEDIATION OF HEAVY METAL POLLUTED SOIL.ppt

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1. Submitted to: Submitted by:
Dr. Mumta Pujari Bharti
Reg. no. 11615783

2. Heavymetals.Heavymetalsaregenerallydefinedasmetals
withrelativelyhigh-densities,atomicweightsoratomic
numbers.E.g.Iron,copper,tin,zinc,cobalt,leadetc.
Heavymetalpollution.Heavymetalpollutionisthe
environmentalpollutionbymetalwithhighrelativeatomic
mass,suchasleadandmercury.Althoughplantsrequire
certainheavymetalsfortheirgrowth,excessiveamountof
thesemetalscanbetoxictoplants.
Bioremediation.Itisaprocessusedtotreatcontaminated
media,includingwater,soilandsubsurfacematerialby
alteringenvironmentalconditionstostimulategrowthof
micro-organismsanddegradethetargetpollutants.

3. BIOREMEDIATION OF HEAVY METAL POLLUTED SOIL
Bioremediationofheavymetalpollutedsoilcanbe
achievedviatheuseofmicro-organisms,plantsorthe
combinationofboth.
1.Usingmicrobesforremediationofheavymetal
pollutedsoil.
•Severalorganismsespeciallybacteria(Bacillus
subtilis,Pseudomonasputida)havebeenusedfor
reductionofCr(VI)tolesstoxicCr(III).
•B.subtilisreducedtheselnitetolesstoxicelemental
Se.

4. Bioremediationcanalsooccurindirectlyvia
bioprecipitationbysulphatereducingbacteria
(Desulflovibriodesulfuricans)whichconvertssulphate
tohydrogensulphatewhichsubsequentlyreactswith
heavymetalssuchasCdandZntoforminsoluble
formsofthesesulphides.
Mostofthemicrobeassistedremediationarecarried
outex-situ.However,averyimportantin-situmicrobe
assistedremediationisthemicrobialreductionof
solublemercuricionsHg(II)tovolatilemetallic
mercuryandHg(0)carriedoutbymercuryresistant
bacteria.Hg(0)canbeeasilyvolatilizeoutofthe
environmentandsubsequentlybedilutedinthe
atmosphere.

5. Biostimulationisanotherprocessusedin
bioremediationofpollutedsoils.Thisprocessinvolves
theadditionofnutrientsinthemanureorother
organicamendmentswhichserveasCsourcefor
micro-organismspresentinsoil.Thisincreasegrowth
andactivityofenzymesinvolvedinremediation
processandthusincreasestheefficiencyof
bioremediation
Biocharisoneoftheorganicmaterialusedin
bioremediation.
TheabilityofthebiochartoincreasethepHofsoil,
unlikemostoftheotherorganicamendmentsmay
increasethesorptionofheavymetals,thusreducing
theirbioavailabilityforplantuptake.

6. 2. Using plant for remediation of heavy metal polluted
soils.
Phytoremediationisanaspectofbioremediationthat
usesplantforthetreatmentofpollutedsoil.
Phytoremediationofheavymetalpollutedsoilcanbe
achievedviadifferentmechanisms.Thesemechanism
are:
1.Phytoextraction.
2.Phytostablization.
3.Phytovolatilization.

7. Phytoextraction.
Most common form of phytoremediation.
Itinvolvesaccumulationofheavymetalsinrootsand
shootsofphytoremediationplants
Therearetwoapproachesforphytoextraction
dependingonthecharacterticsoftheplantinvolvedin
theprocess.
1.Useofnaturalhyperaccumulators.
2.Useofhighbiomassplantswhoseabilityto
accumulateheavymetalsisinducedbytheuseof
chelates,i.e.soilamendmentswithmetalmobilizing
capacity.

8. Phytostabilization.
Itinvolvesusingplantstoimmobilizemetal,thus
reducingtheirbioavailabilityviaerosionandleaching.
Itismostcommonlyusedwhenphytoextractionisnot
desirableorpossible.
Ittakesplaceasaresultofprecipitation,sorption,
metalvalencereduvtion,orcomplexation.
Theefficiencyofphytostabilizationdependsonthe
plantandsoilamendmentused.

9. Phytovolatilization.
In this form of phytoremediation, plant are used to
take up pollutants from the soil.
These pollutants are transformed into volatile forms
and are subsequently transpired into a atmosphere.
It is most commonly used for the remediation of soil
polluted with Hg.
e.g. Nicotiana tobacum and Arabidopsis thaliana are
used in phytovolatlization of Hg.

10. Combined use of plant and microbes.
Thecombineduseofbothmicrobesandplantsforthe
phytoremediationofheavymetalpollutedsoils,
resultsinafasterandmoreefficientcleanupofthe
pollutedsite.
Mycorrhizalfungiisalsousedforbioremediation.
Mycorrhizaeemploydifferentmechanismfor
remediationofheavymetalpollutedsoil.
Theyimmobilizeheavymetalandthusreducemetal
concentrationinplants.

11. PGPRhavebeenusedinphytoremediationstudiesto
reduceplantstressassociatedwithheavymetal
pollutedsoils.
EnhancedaccumulationofheavymetalssuchasCd
andNibyhyperaccumulatorshasbeenabsorbedwhen
theplantwereinnoculatedwithBacillussp.

12. Refrence
G. V. Chibuike and S. C. Obiora “Heavy metal polluted
soil: effects on plants and bioremediation methods”
Hindawi Publishing Corporation. Applied and
environment soil science volume-2014

13. THANK YOU