Phytoremediation is a way to mitigate environment pollutions, such as in air, water and soil pollution in virtue of plants, more often than not, combined with their associated microorganisms. This concept has been widely applied to treat pollutants in soil and water
Principles of phytoremediation
Briefly, for phytoremediation, roles from roots to shoots are played in phytostabilization, rhyzodegradation, phytoextraction, phytodegradation, phytovolatilization and phytofiltration
It is the process for phytostabilization that contaminants were sequestrated, but not degraded, in the root zones. The narrow region of 1-3 mm from root surface is rhyzosphere, where there are much more profuse microorganisms than in bulk soil. Root secretions and rhyzospheric microorganisms are joint-agents to degrade the pollutants in soil in the process of rhyzodegradation. Phytoextraction is with regard to extracting pollutants from soil and translocating them from the roots to shoots by plants. Phytodegradation is to transform and/or degrade pollutants, which enter the plants from soil, water or air. Phytovolatilization means the pollutants are volatile out of the stoma of the plants and degraded by hydroxyl radicals, otherwise they will become air pollutants. It is phytofiltration that particulate matters in air are reduced through the surface of plants
Characteristics of phytoremediation
Phytoremediation is proved to be helpful to reduce pollutants in soil, water and air; it is energy-economizing and cost-effective compared with those physical or chemical methods since it is solar-energy driven cleanup technology; it is a preference for people as its aesthetic value and less environment disruption, which letting nature take its course.
Plants are also living things, and there exists tolerance limits for the toxicity of pollutants; it is a kind of “leave it to chance” thing since it is too natural to disrupt the environment: optimum concentrations of pollutants for remediation varying with species of plants, intermediates possibly leading remediation varying with species of plants, intermediates possibly leading to second pollutants, time-consuming when considering growth period of plants.