Decontaminated environment is one of the major challenge for 21st century. Most of the traditional remedial technologies which are more expensive like incineration, thermal vaporization, solvent washing etc, essentially kills or damage the biotic components of soil, thereby degrading the quality of environment. So phytoremediation is one of the low cost and low impact alternative to these remedial technologies.

It is an eco-sustainable, non invasive, highly promising, solar driven technology for in situ treatment of environmental pollutants, involving engineered use of plants with their associated microbes.

Phytoremediation technologies
Also called phytotechnologies, are the group of techniques that make the use of green plants to achieve environmental agenda's. Some phytotechnology are discussed hereunder:
a) Phytoextraction: Use of green plants that accumulate pollutants and remove them from soil via root absorption and concentrating them in above ground harvestable plant parts.
b) Rhizofilteration: Use of both terrestrial or green plants to absorb, concentrate and precipitate pollutants with low concentration in their shoot.
c) Phytostabilization: In-place inactivation or phytoimmobilization of pollutants under plant rhizosphere by limiting their mobility and phytoavailability in soil and water, thereby preventing their migration into ground water and spread through the food chain.
d) Phytovolatilization: Uptake of pollutants and their release in atmosphere, comparitively at low concentration which is non-toxic to living beings.
e) Phytodegradation: Breakdown or conversion of highly toxic organic pollutants into their less toxic form via the action of enzymes, secreted within plant tissues.

Plants involved
Also called as hyperaccumulators, are those plants which can accumulate desired level of pollutants concentration in their shoot. Ideal plants should have the ability to accumulate high pollutants concentration, fast growth rate, high biomass, easily harvestable, tolerate high salt concentration and pH and must translocate pollutants to aerial parts efficiently. Some plants of interest include Thlaspi sp., Arabidopsis sp., Sedum alfredii sp. etc.

In situ remediation
Low cost method
Aesthetically valuable
Remedy at remote locations
After applications, land remain for cultivation

Time consuming
Require more land
Sometime pollutants cause phytotoxicity and inhibit plants growth
Disposal of polluted plant material is a big problem

Phytoremediation is the most suitable technology for the developing countries, where the problem of funding is a major issue. Future research is required to develop genetically altered plants via genetic engineering for effective phytoremediation.

About Author / Additional Info:
Gaurav Saxena
Babasaheb Bhimrao Ambedkar (Central) University
Lucknow (U.P)- 226 025 India