Phytoremediation is the use of plants to degrade, remove or stabilize contaminants in soil, air or water. Some of the benefits of phytoremediation include low installation cost, little maintenance and potential to remove, stabilize and degrade a variety of different contaminants while causing little disruption to the surrounding areas.
A study by Lone et al. (2008) showed that phytoremediation is more cost-effective and has fewer side effects on the environment as compared to the physical and chemical approaches to purifying soils, water and air. The study notes that as of 2008, scientists had identified more than 400 plant species that can be used to cleanse the soil and water. Phytoremediation has proved useful in cleaning soils in spite of them having complex structures, vastness and lack
of uniformity in several aspects such as components and mineral presence.
The Study adds that the recent developments in biotechnology promise the development of new plant species which are hyperaccumulators. Theses plant species will be developed on the basis if scientists transferring metal hyperaccumulating genes from some low biomass species to those species that have high biomass (UNEP 2016). When cultivates in mass, these new plants will have greater efficiency in cleansing soils.
In the face of increasing soil pollution through the deposition of heavy metals, there is need for the adoption of phytoremediation so that the pollutants are dealt with in a cheap, sustainable manner and environmentally friendly manner. Some of the metals commonest in soils in high quantities include copper, lead, Cadmium, Nickel, mercury, chromium and Zinc (Lone et al., 2008). These metals have the potential to cause toxicity in human nutrition when consumed in food once they are taken up by plants. For instance, consuming food containing high amounts of Cadmium and Zinc can cause respiratory and gastrointestinal problems (Lone et al., 2008). Moreover, the concentrations of metal pollutants in the sol can affect the physiological and biochemical processes of the plants growing on such soils leading to poor growth and the dying out of such plants.
Proper phytoremediation must take into account the physical, chemical and biological properties of the soil such as its texture and structure as well as the minerals and vital components available. This is done so that growing plants on that soil does not drain it of some minerals which may thereafter necessitate the addition of chemicals and undo the cleaning works done by the plans planted for phytoremediation purposes (Lone et al., 2008). The things to check for prior to starting a phytoremediation include the salt solubility, chemical reactions, PH of the soil, drainage, solute movement and content, current microbial activities and the bioavailability of metal ions in the soil (Lone et al., 2008).
The beauty of using phytoremediation is that it can be used to decontaminate the soil from both organic and inorganic pollutants. Since plants duffer greatly in their abilities to accumulate heavy metals and other pollutants, careful selection of the plant species to be planted must be made depending on the soils condition and the desired level of chemical retention in the soil (United Nations Environmental Programme (UNEP), 2016). Moreover, the mechanisms of phytoremediation may include phytoextraction (for the removal of pollutants), phytofiltration (removing pollutants from aqueous waste), phytostabilization (removal of pollutants from the soil and storing them in the rhizosphere), and phytovolatization (retention of the pollutants in the foliage of the plants) (Lone et al., 2008).
These approaches of phytoremediation are better than the other methods such as excavating for wastes and then burning or burying them at grounds deemed to be safer. The phytoremediation is also better than use of chemicals such as those used to balance the PH of the soil.
References
Lone et al. (2008) Phytoremediation of heavy metal polluted soils and water: Progresses and perspectives J Zhejiang University Science B. Mar; 9(3): 210–220.
United Nations Environmental Programme (UNEP) (2016) Phytoremediation: An Environmentally Sound Technology for Pollution Prevention, Control and Remediation. An Introductory Guide To Decision-Makers retrieved 8 March 2016 from http://www.unep.or.jp/Ietc/Publications/Freshwater/FMS2/2.asp
