Phytoremedation

• Environmental Bioremediation


  Using living organisms, new materials, transformed biomass, or a combination of these elements to remediate polluted environments
• Environmental biotechnology proposes strategies that are safer and present lower costs to efficiently remediate air, water, and soil from polluted environs than the physicochemical treatments generally applied with this purpose
• Important Biotechnological Strategies to remediate Polluted Environments


  • Phytoremediation
  • Bioremediation
  • Biochar
  • Biosorption
  • Biosynthesized Nanomaterials
• Phytoremediation


  Promising economic effective biotechnology that uses plants for the cleaning of polluted environments
• Phytoremediation can be used for inorganic and organic contaminants present in the soil, air, water & sludge
• Categories of phytoremediation


  • Phytoextraction
  • Phytofiltration
  • Rhizodegradation
  • Phytodegradation
  • Phytostabilization
  • Phytovolatization
• Characters of Successful Phytoremediator


  • Fast growth (up to 3 meter / year)
  • Long lived
  • Propagate easily from cuttings (vegetative means)
  • Can be harvested and regrown from the stump
  • High transpiration rate
  • Not part of food chain
  • Potential for use in other products or source of biomass and energy
• Phytoremediation Technologies


  • Phytoextraction
  • Phytostabilization
  • Rhizofiltration
  • Phytovolatilization
  • Rhizodegradation
  • Phytodegradation
• Hydraulic barriers


  Large trees, particularly those with deep roots (e.g., Populus sp.), remove large quantities of groundwater during transpiration. Contaminants in this water are metabolized by plant enzymes, and vaporized together with water or simply sequestered in plant tissues
• Vegetation covers


  Herbs (usually grasses), eventually shrubs or trees, establish on landfills or tailings, are used to minimize the infiltration of rain water, and contain the spread of pollutants. The roots increase soil aeration thus, promoting biodegradation, evaporation and transpiration
• Constructed wetlands


  Man-made systems that mimic the processes occurring in natural wetlands, designed to treat wastewater by utilizing the natural functions of wetland vegetation, soils, and their associated microbial assemblages. They are particularly effective in removing pollutants such as organic matter, nutrients, and pathogens, thereby improving water quality
• Phytodesalination


  A recently reported emerging technique that utilizes halophytes to remove excess salts from saline soils. The potential of Suaeda maritima in removal and accumulation of NaCl, from highly saline soils, has been demonstrated
• Phytoremediation advantages


  • In situ and passive technique
  • Uses solar energy and is low cost
  • Has reduced environmental impact and contributes to the landscape improvement
  • High acceptance by the public
  • Provides habitat for animal life
  • Reduction in dispersal of dust and contaminants by wind
  • Reduction of surface runoff
  • Reduction of leaching and mobilization of contaminants in soil
  • Harvesting of the plants or organs that have accumulated metals is easy to accomplish with existing technology
  • The harvested biomass can be economically valuable
  • Plant process more easily controlled than those of microorganisms
• Phytoremediation disadvantages


  • Limited to shallow soils or where contamination is localized to the surface (< 5 m)
  • Still under development and therefore not accepted by many regulatory agencies
  • There is little knowledge of farming, genetics, reproduction and diseases of phytoremediating plants
  • Metal concentrations in the soil can be toxic and lethal to plants
  • Generally, plants are selective in metal remediation
  • Treatment slower than the traditional physico-chemical techniques
  • Contamination may spread through the food chain if accumulator plants are ingested by animals
  • Efficient phytoremediating plants may not adapt to climatic and environmental conditions at contaminated sites
  • If the plants release compounds to increase the mobility of the metals, these can be leached into groundwater
  • The area to be decontaminated must be large enough to allow application of cultivation techniques
  • Toxicity and bioavailability of degradation products remain largely unknown
• Phytoextraction


  The uptake of contaminants by plant roots and its translocation within the plant. Contaminants are generally removed by harvesting the plants. It is used in the treatment of soil, sediment, and sludge and to a lesser extent for treatment the contaminated water
• Characteristics of plants used in phytoextraction


  • Tolerance to high concentrations of metals
  • Accumulate high concentrations in their aerial tissues
  • Rapid growth
  • High biomass production
  • Profuse root system
  • Easy to cultivate and harvest
• Bioconcentration factor (BCF)


  Ratio of the total concentration of element in the harvested plant tissue to its concentration in the soil in which the plant was growing
• Translocation factor (TF)


  Ratio of the total concentration of elements in the aerial parts of the plant to the concentration in the root
• Phytostabilization


  Aims at reducing the mobility of contaminants in the soil by covering contaminated soil with vegetation tolerant to high concentrations of toxic elements, limiting the soil erosion and leaching of contaminants into groundwater
• Rhizofiltration


  The adsorption or precipitation onto plant roots, or absorption into the roots of contaminants that are in solution surrounding the root zone, due to biotic or abiotic processes
• Rhizodegradation


  The breakdown of an organic contaminant in soil through microbial activity that is enhanced by the presence of the root zone
• Phytodegradation


  The breakdown of contaminants taken up by plants through metabolic processes within the plant, or the breakdown of contaminants external to the plant through the effect of compounds (such as enzymes) produced by the plants
• Phytovolatalization


  The uptake and transpiration of a contaminant by a plant, with release of the contaminant or a modified form of the contaminant to the atmosphere from the plant through contaminant uptake, plant metabolism, and plant transpiration
• Important Phytoremediator Species


  • Indian mustard (Brassica juncea L.)
  • Salix species
  • Populus deltoides
  • Sunflower (Helianthus Annuus L.)
• What is Rhizodegradation?


  Rhizodegradation is the breakdown of an organic contaminant in soil through microbial activity that is enhanced by the presence of the root zone.
• What is the Root Zone?

  The area around plant roots where the soil is rich in nutrients and microorganisms that break down organic matter and contaminants.
• What is the role of Microbial Activity in Rhizodegradation?

  Microbial activity is increased by the presence of plant roots, leading to enhanced biodegradation of contaminants.
• What is the Soil Microbiome?

  The community of microorganisms living in the soil that play a crucial role in Rhizodegradation.
• Why is Rhizodegradation environmentally important?

  Rhizodegradation helps clean contaminated soil, promoting environmental sustainability and reducing ecological risks.
• How do plant roots enhance microbial activity?


  Through root exudates, providing a source of energy and nutrients.
• What is the effect of root exudates on microorganisms?

  Root exudates stimulate microbial growth and activity.
• How do roots modify the soil environment?

  By creating microsites with higher oxygen levels and modifying pH conditions.
• What effect do plant roots have on microbial interactions?

  Roots facilitate interactions between microorganisms, promoting cooperation and competition.
• What is the role of enzymes in Rhizodegradation?

  Microorganisms associated with plant roots produce enzymes that break down organic contaminants.