Phytoremediation: The Wave of the Future

Abstract

As the industrial age developed, societies have allowed large amounts of contaminants to enter the environment unchecked. As a result of this neglect, the incidence of heavy-metal contaminated sites has been on the rise. These sites are polluted with toxic hydrocarbons and radionuclides, as well as heavy metals, such as cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn). The result is unsightly areas left untreated, undeveloped and are accurately referred to as “Brown Fields.” Heavy metals in the soil can create a contaminated and possibly toxic top layer ranging 2–5 cm deep in addition to the possibility of entering the food chain. The typical and most common method of removing contaminants is to excavate the soil by mechanical means and store it at off-site locations.

Phytoremediation is an innovative, emerging technology that utilizes plant species to remove contaminants from the environment using a distinct set of plant-based technologies. Four types of remediation technologies have been employed: (1) phytostabilization is the use of a plant’s root system to stabilize the metal-contaminated soil thus preventing the spread of the contaminant; (2) phytodegradation is the process of using plants to convert toxic contaminants into less toxic forms; (3) rhizofiltration is the process of using plants to clean aquatic environments; and finally, (4) phytoextraction is the practice of using plants to take up metals from the soil and translocate them to the above-ground tissues which can then be harvested. By utilizing phytoremediation techniques, the environmental disruption is minimized, soil fertility is maintained, secondary air- and water-borne wastes are reduced, and these techniques are well received by the public as in situ methods. This chapter will discuss the use of multiple plant species in each of the listed remediation techniques for the goal of rejuvenating Earth’s ecosystems.