We take a closer look at 5 of best plants for phytoremediation. Brassicaceae species are really useful to accumulate certain metals while. Phytoremediation /ˌfaɪtəʊrɪˌmiːdɪˈeɪʃən refers to the technologies that use living plants . Processes. Phytoremediation process. A range of processes mediated by plants or algae are useful in treating environmental problems. Phytoremediation entails the use of plants to mitigate the effects of some type of Plants that have been employed and are useful in parts of Appalachia include: .
Plants Phytoremediation? in are Which Useful
Similarly, the availability of uranium and radio-cesium can be enhanced using citric acid and ammonium nitrate, respectively. Rhizofiltration is similar to phyto-accumulation, but the plants used for cleanup are raised in greenhouses with their roots in water. This system can be used for ex-situ groundwater treatment.
That is, groundwater is pumped to the surface to irrigate these plants. Typically hydroponic systems utilize an artificial soil medium, such as sand mixed with perlite or vermiculite. As the roots become saturated with contaminants, they are harvested and disposed of. In this process, plants take up water containing organic contaminants and release the contaminants into the air through their leaves.
In this process, plants actually metabolize and destroy contaminants within plant tissues. In this process, trees indirectly remediate by controlling groundwater movement. Trees act as natural pumps when their roots reach down towards the water table and establish a dense root mass that takes up large quantities of water.
A poplar tree, for example, pulls out of the ground 30 gallons of water per day, and a cottonwood can absorb up to gallons per day. The plants most used and studied are poplar trees. Air Force has used poplar trees to contain trichloroethylene TCE in groundwater. In Iowa, EPA demonstrated that poplar trees acted as natural pumps to keep toxic herbicides, pesticides, and fertilizers out of the streams and groundwater.
The US Army Corps of Engineers has experimented with wetland plants to destroy explosive compounds in the soil and groundwater. Sunflowers, using rhizofiltration, were used successfully to remove radioactive contaminants from pond water in a test at Chernobyl, Ukraine. The toxicity and bioavailability of biodegradation products is not always known.
Degradation by-products may be mobilized in groundwater or bio-accumulated in animals. Additional research is needed to determine the fate of various compounds in the plant metabolic cycle to ensure that plant droppings and products do not contribute toxic or harmful chemicals into the food chain. Scientists need to establish whether contaminants that collect in the leaves and wood of trees are released when the leaves fall in the autumn or when firewood or mulch from the trees is used. Disposal of harvested plants can be a problem if they contain high levels of heavy metals.
In addition, high levels of arsenic in agricultural land degrade soils, reduce crop yields, and introduce the pollutant to the food chain 8. Scientists have engineered Arabidopsis plants with arsenic tolerance by introducing two bacterial genes: Double transgenics are not only highly tolerant of arsenic, they also have improved cadmium tolerance, and a six-fold increase in the level of biomass compared to wild-type controls 6.
Although the use of biotechnology to develop transgenic plants with improved potential for efficient, clean, cheap, and sustainable bioremediation technologies is very promising, several challenges remain. Biotech Plants for Bioremediation The Mess Over the last century, global industrialization, war, and natural processes have resulted in the release of large amounts of toxic compounds into the biosphere.
Conventional Remediation Strategies Conventional remediation for polluted sites typically involves the physical removal of contaminants, and their disposal in a designated site.
Phytoremediation Phytoremediation, the use of plants to remove or degrade contamination from soils and surface waters, has been proposed as a cheap, sustainable, effective, and environmentally friendly alternative to conventional remediation technologies. Cadmium, Zinc, Lead, and Selenium Toxic metals affect crop yields, soil biomass, and fertility, and accumulate in the food chain. Herbicides Mammalian P cytochrome genes have been used to confer herbicide resistance to crop plants, which can be used in herbicide rotation systems designed to delay the evolution of herbicide resistance in weeds, and to reduce the environmental load of agricultural chemicals 5, 6.
Explosives Millions of tons of explosives have been released into the environment, with the resulting pollution of vast expanses of land and water resources. Landmines Landmines affect millions of people, both combatants and civilians, in over 80 countries.
Mercury Mercury is a highly toxic element found both naturally and as an introduced contaminant in the environment, and is a very serious global environmental problem.
Arsenic Arsenic occurs naturally in rocks and soil, and is released into underground water. Prospects Although the use of biotechnology to develop transgenic plants with improved potential for efficient, clean, cheap, and sustainable bioremediation technologies is very promising, several challenges remain.
A better understanding of the molecular basis of the pathways involved in the degradation of pollutants is needed. Further analysis and discovery of genes suitable for phytoremediation is essential. Phytoremediation technologies are currently available for only a small subset of pollutants, and many sites are contaminated with several chemicals.
Therefore, phytoremediators need to be engineered with multiple stacked genesin order to meet the requirements of specific sites. Phytoremediation technology is still at an early development stage, and field testing of transgenic plants for phytoremediation is very limited.
Biosafety concerns need to be properly addressed, and strategies to prevent gene flow into wild species need to be developed. The true costs of benefits of phytoremediation with biotech plants must be determined.
Political will and funding are required, both to pursue basic research into phytoremediation, and to implement novel strategies. First, they should survive and grow fast in the contaminated environment and tolerate the high concentrations of pollutants. Second, at best they should be native plants to the desired site because every plant has its own habitat. Third, they should have highcapacities to remove one or more pollutants. Therefore, it is a tough challenge to find the right plants for each and every pollutant.
Although phytoremediation is a promising technique to remove pollutants, it is still an immature and developing technology to deal with pollution problems. Scientists are the bridgeswho connect suitable plants and troublesome pollutants.
There is still a lot not known regarding reaction mechanisms in phytoremediation. To combine the characteristics of many genes, transgenic plants may also provide agood option in the future for phytoremediation. However, it is clear that phytoremediation already plays an important role inremoving pollutants from the environment -- we just need to find the right plant for the right pollutant. Our task as scientists is to make this happen.
International Journal of Chemical Engineering
Phytoremediation is a good option. Using green plants as weapons, phytoremediation is one of most economical and environment-friendly techniques to target. Plants in phytoremediation work on concentrating specific elements, how do we dispose them the plants would eventually biodegrade and the contaminants. PDF | S.W. Gawronski and others published Plant taxonomy and Plant species useful for phytoremediation need to fulﬁll some requirements.