How scientists plan to use plants to remove toxic metals from soil
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How scientists plan to use plants to remove toxic metals from soil
Subject: Science & Technology
Section: Science
Context: ‘Heavy metal pollution of the soil’
Content: Heavy metals are elements that exhibit metallic properties such as ductility, malleability, conductivity, cation stability, and ligand specificity.
- Some heavy metals such as Co, Cu, Fe, Mn, Mo, Ni, V, and Zn are required in minute quantities by organisms. However, excessive amounts of these elements can become harmful to organisms.
- Other heavy metals such as Pb, Cd, Hg, and As (a metalloid but generally referred to as heavy metal) do not have any beneficial effect on organisms and are thus regarded as the “main threats” since they are very harmful to both plants and animals.
- The reason for soil contamination could be manufacturing, mineral extraction, accidental spills, illegal dumping, leaking underground storage tanks, pesticide and fertiliser use etc
Phytoremediation is a realistic and promising strategy for heavy metal removal from polluted areas, based on the employment of hyper-accumulator plant species that are extremely tolerant to heavy metals present in the environment/soil.
- Green plants are used to remove, decompose, or detoxify hazardous metals in this technique. For soil decontamination, five types of phytoremediation methods have been used viz.
- Phytostabilization,
- Phytodegradation,
- Rhizofiltration,
- Phytoextraction And
- Phytovolatilization
A hyperaccumulator is a plant capable of growing in soil or water with very high concentrations of metals, absorbing these metals through their roots, and concentrating extremely high levels of metals in their tissues.
- The metals are concentrated at levels that are toxic to closely related species not adapted to growing on the metalliferous soils.
- Bioremediation is an effective method of treating heavy metal polluted soils. It is a widely accepted method that is mostly carried out in situ; hence it is suitable for the establishment/reestablishment of crops on treated soils.
- Using plants for the treatment of polluted soils is a more common approach in the bioremediation of heavy metal polluted soils.
- Combining both microorganisms and plants is an approach to bioremediation that ensures a more efficient clean-up of heavy metal polluted soils.
