Phytoremediation

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Phytoremediation

• Dr. Tini Surtiningsih, Ir., DEA

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Phytoremediation

• Phytoremediation is the use of plants, trees and
  herbaceous species to eliminate or degrade
  contaminants or reduce their bioavailability in
  both water and soil.
• Many chemical species that can be treated with
  phytoremediation techniques, which comprise
• heavy metals
• organic compounds such as pesticides, solvents,
  and other persistent pollutants (PCBs)

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• Phytoremediation can be applied as long as the
  concentration of the pollutant is within an
  appropriate concentration range, which shall not
  be too high, since it may cause phytotoxicity to
  the plant

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Phytoremediation can be performed following
different methods

• Phytoextraction Uptake and concentration of
  pollutants from the environment into the plant
  biomass.
• Phytostabilization Reduction of the mobility of
  the contaminants in the environment.
• Phytotransformation Chemical modification of the
  environmental substances as a direct result of
  the plant metabolism.

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• Phytostimulation Enhancement of the native soil
  microbial activity for the degradation of
  contaminants.
• Phytovolatilization Removal of substances from
  soil or water with release into the air.
• Rhizofiltration Filtering water through a mass
  of roots to remove toxic substances or excess
  nutrients.

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• Regarding the rhizosphere, there are other
  techniques besides the rhizofiltration.
• The roots can be used as stimulator of the
  micro-organisms living there due to the exudates
  that plants expulse in this medium.
• This can increase the amount of organisms in 2 or
  3 orders of magnitude.

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• Within remediation, one of the most important
  factors to take into account is the tolerance of
  the plant.
• The same chemical species may produce different
  effects at the same concentration in different
  plants.
• For this reason, it is important to know about
  the background levels in the polluted area
• Sites with natural high concentration of some
  pollutant may lead to an increased presence of
  tolerant species.
• These species are of big interest for
  phytoremediation and hence many are used for
  remediation purposes.

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• These plants are able to accumulate due to
  different detoxifying mechanisms such as the
  chelation of heavy metals or the storage of the
  contaminants in vacuoles or the cellular wall
• Plants which are able to accumulate extremely
  high concentrations in their tissues are
  considered hiperaccumulator species. Although
  their ability of accumulating high concentrations
  of metals is highly interesting, these species
  normally only show low growth rates and hence are
  not suitable for extracting high amounts of
  pollutants from the soil.

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• However there are plants which are able to
  accumulate lower concentrations of metal but
  present higher growth rates. For this reason,
  these species showed to be more suitable for
  phytoextraction processes.
• The low accumulation capacity of these species
  may be highly improved by the addition of
  synthetic chelates, which increase the solubility
  of metal in the soil, making them more
  bioavailable for the plant and hence increasing
  the uptake rate of metals by the plant

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• . Examples of chelating agents are EDTA, NTA or
  weak organic acids, such as citric acid.
  Chelates, however, have to be used with caution,
  since they may increase the mobility of
  pollutants, posing a risk of contamination of
  underlying groundwaters
• They may also provoke negative effects for the
  native microbial community of the soil. In
  particular, EDTA has recently been banned as a
  chelating agent, due to its toxicity for the soil
  microbiota and its high persistence.

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• These plants are able to accumulate due to
  different detoxifying mechanisms such as the
  chelation of heavy metals or the storage of the
  contaminants in vacuoles or the cellular wall
• Plants which are able to accumulate extremely
  high concentrations in their tissues are
  considered hiperaccumulator species. Although
  their ability of accumulating high concentrations
  of metals is highly interesting, these species
  normally only show low growth rates and hence are
  not suitable for extracting high amounts of
  pollutants from the soil.

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• However there are plants which are able to
  accumulate lower concentrations of metal but
  present higher growth rates. For this reason,
  these species showed to be more suitable for
  phytoextraction processes.
• The low accumulation capacity of these species
  may be highly improved by the addition of
  synthetic chelates, which increase the solubility
  of metal in the soil, making them more
  bioavailable for the plant and hence increasing
  the uptake rate of metals by the plant

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• Examples of chelating agents are EDTA, NTA or
  weak organic acids, such as citric acid.
  Chelates, however, have to be used with caution,
  since they may increase the mobility of
  pollutants, posing a risk of contamination of
  underlying groundwaters
• They may also provoke negative effects for the
  native microbial community of the soil. In
  particular, EDTA has recently been banned as a
  chelating agent, due to its toxicity for the soil
  microbiota and its high persistence.

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• To improve the effectiveness of these
  technologies, genetic manipulation of some
  organisms can be used.
• For example, tobacco plant was inoculated with
  bacterial genes encoding a nitroreductase enzyme.
  
• Genetically engineered tobacco plant showed a
  significantly faster degradation of TNT and an
  enhanced resistance to the toxic effect of the
  explosive.

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• Regarding the economical aspects of these
  technologies, some studies suggest that when a
  phytoremediation process is used instead the
  conventional processes,
• the costs may be reduced up to 50-60.
• However, the effectiveness of the process has to
  be taken into account.
• Although the price is significantly lower,
• the time needed for the remediation may be much
  longer.

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• No specific regulatory standards have been
  developed for phytoremediation processes, so that
  installations must be approved on a case by case
  basis. There are several regulatory issues which
  will need to be addressed on most sites
• Several methods exist for the disposal of the
  harvested pollutant-rich crop after a
  phytoextraction process Pre-treatment processes
  aim to reduce the volume of biomass to be
  treated, by strongly reducing its water content.
  Composting, compactation and pyrolisis are the
  most important ones. After the pre-treatments,
  the final disposal of vegetal material takes
  places.

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• Although the only technique used in praxis is the
  incineration (in combination with filtering
  mechanisms to clean the gas effluent), other
  techniques exist, such as the direct disposal in
  a deponie.
• Other techniques also are being developed at a
  laboratory scale, such as the ashing or the
  liquid extraction techniques. However they still
  lack the required technology for its on-field
  application

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• Phytoremediation is an emerging and promising
  technology which permits a low cost alternative
  to other remediation processes.
• However, the mechanisms behind the remediation
  process still need to be better understood, so
  that the best species-pollutant combination can
  be chosen.
• Other problems such as contaminant migration need
  to be focused in further studies to minimize the
  drawback of this new technology.

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• TERIMA KASIH ATAS PERHATIANNYA
• Wassalamualaikum Wr. Wb.

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Fitoremediasi

• Fitoekstraksi/fitoakumulasi
• Rhizofiltrasi
• Fitostabilisasi, mobilisasi logam
• Fitodegradasi/fitotransformasi,
  menguraikan/menghancurkan log berat
• Fitovolatilasi
• Rhizodegradasi, mikroba rhizosfir

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Kelebihan fitoremediasi

• Memanfaatkan cahaya matahari
• Biaya murah
• Mudah diterima masyarakat
• Bioremediasi EXSITU, mahal
• Bioremediasi INSITU, lebih murah

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Keterbatasan fitoremediasi

• Terbatas pada air dan tanah
• Cara kerja lambat
• Meracuni tnaman
• Potensi racun masuk makanan
• Racun sulit diketahui jenisnya
• Hanya untuk lingkungan tanah dan air

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Jenis tanaman fitoremediasi

• Bunga matahari/ Heliantus anuus mendegradasi
  Uranium
• Populas trichocarpa, P.deltaritas Famili
  sacnaceae mendegradasi TCE (Trichloroethylene)
• Najar graminae (tumbuhan air) menyerap Co,
  Pb,Ni
• Vetiver grass (Vetiveria zizonaides), akar wangi
  mendegradasi Pb, Zn

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Tanaman air fitoremediasi

• Menyerap/mengakumulasi logam berat pada semua
  jaringan
• Kangkung air
• Teratai
• Eceng gondok

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Bioremediasi dengan mikroba

• Dengan 2 cara
• Oxidasi, bersamaan pertumbuhan mikroba
• Reduksi, elektron akseptor
• Akumulasi logam pada dinding sel
• Akumulasi logam dalam vakuola sel
• Menghasilkan enzim pendegradasi logam, eksoenzim
  diluar sel, endoenzim dalam sel

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Mikroba bioremediasi logam

• Bakteri mentransformasi Fe Thiobacillus,
  Leptothrix, Crenothrix,Sulfolobus, Gallionela
• Bakteri mentransformasi Mn
• Arthrobacter, Leptothrix, Sphaerotillus
• Hg Pseudomonas, Bacillus