Phytoremediation: A Green Technology to Remove Environmental Pollutants

Abstract

Land, surface waters, and ground water worldwide, are increasingly affected by contaminations from industrial, research experiments, military, and agricultural activities either due to ignorance, lack of vision, carelessness, or high cost of waste disposal and treatment. The rapid build-up of toxic pollutants (metals, radionuclide, and organic contaminants in soil, surface water, and ground water) not only affects natural resources, but also causes major strains on ecosystems. Interest in phytoremediation as a method to solve environmental contamination has been growing rapidly in recent years. This green technology that involved "tolerant plants" has been utilized to clean up soil and ground water from heavy metals and other toxic organic compounds. Phytoremediation involves growing plants in a contaminated matrix to remove environmental contaminants by facilitating sequestration and/or degradation (detoxification) of the pollutants. Plants are unique organisms equipped with remarkable metabolic and absorption capabilities, as well as transport systems that can take up nutrients or contaminants selectively from the growth matrix, soil or water. As extensive as these benefits are, the costs of using plants along with other concerns like climatic restrictions that may limit growing of plants and slow speed in comparison with conventional methods (i.e., physical and chemical treatment) for bioremediation must be considered carefully. While the benefits of using phytoremediation to restore balance to a stressed environment seem to far outweigh the cost, the largest barrier to the advancement of phytoremediation could be the public opposition. The long-term implication of green plant technology in removing or sequestering environmental contaminations must be addressed thoroughly. As with all new technology, it is important to proceed with caution.Keywords: Phytoremediation; Green Technology; Pollutants; Contaminants; Toxic Metals Green TechnologyThe success of green technology in phytoremediation, in general, is dependent upon several factors. First, plants must produce sufficient biomass while accumulating high concentrations of metal. In some cases, an increased biomass will lower the total concentration of the metal in the plant tissue, but allows for a larger amount of metal to be accumulated overall. Second, the metal-accumulating plants need to be responsive to agricultural practices that allow repeated planting and harvesting of the metalrich tissues. Thus, it is preferable to have the metal accumulated in the shoots as opposed to the roots, for metal in the shoot can be cut from the plant and removed. This is manageable on a small scale, but impractical on a large scale. If the metals are concentrated in the roots, the entire plant needs to be removed. Yet, the necessity of full plant removal not only increases the costs of phytoremediation, due to the need for additional labor and plantings, but also increases the time it takes for the new plants to establish themselves in the environment and begin ...

Induced changes in the growth of four plant species due to lead toxicity

“…The selection of phytoextraction plants aims to identify species that are tolerant to the contaminant, which must exhibit characteristics such as fast growth and sufficient biomass production to accumulate greater contents of metals, especially in the shoots (Paz-Alberto & Sigua, 2013). Plants intended for phytostabilization must be limited to the accumulation of the metal in the roots (Magalhães et al, 2011).…”

The potential of wild vegetation species of Eleusine indica L., and Sonchus arvensis L. for phytoremediation of Cd-contaminated soil

“…Plants with specific genetic characteristics are able to grow and accumulate heavy metals. Certain types of plants will be able to maintain the ability of heavy metal accumulation through absorption and precipitation (Alberto and Sigua, 2013). This experiment showed that both plants are having relatively similar characteristics, even though E indica is taller than S. arvensis.…”

“…Alberto and Sigua (2013) pointed out that in general, the success of phytoremediation technology depends on several factors. First, the plant should produce enough biomass as well as absorb high heavy metals.…”

“…The plants that have massive rooting systems are capable of reducing heavy metal concentration in soils. According to Alberto and Sigua (2013), plants that are able to decontaminate contaminated soil have some characters, i.e. 1) the occurrence of plant uptake from soil or fluid that contaminated to the root, 2) bind the contaminants into the tissues of plants, and 3) carries contaminants from the root to the top of the plant as well as prevent or inhibit the contaminants from the soil.…”

Gas exchange responses of two poplar clones (Populus euramericana (Dode) Guinier 561/41 and Populus nigra Linnaeus 63/135) to lead toxicity

“…On the other hand, trees have the capability to effectively stabilize the soil with their root system, prevent erosion, and reduce the spread of contaminants. Also, trees can be easily harvested and removed from the area with minimal risk, effectively taking with them a high quantity of the contaminants that were present in the soil (Paz-Alberto, Sigua 2013;Chandra, Kang 2015).…”