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Bioremediation for Sustainable Environmental Cleanup

from the contaminant type, the concentration of the contaminant should also be estimated prior

to the phytoremediation to prevent the toxicity effects on healthy plants. The non-aqueous phase

pollutants create adverse effects on plant growth. Pollutants with low bioavailability are difficult to

extract with phytoremediation process (EPA 2000).

5.3.2.2 Selection of Plant Species

It requires substantial information regarding the plant biological system before deciding its

suitability for phytoremediation of a given area. The root system of the plants significantly affects the

phytoremediation potential. Fibrous roots offer the advantage of greater surface area for adsorption

and hence extraction of the pollutant. On the other hand, tap roots possess central large roots

extending in the deeper soil layers, thus can extract the pollutant from the deeper layers (Schwab

1998). The desirable root depth for phytoremediation varies for different plants. Non-woody plant

roots have shown efficient removal with feet depth, whereas tree roots less than 10–20 feet are found

to be most effective (Gatliff 1994). The scrutiny of seed source and seed health is also imperative

before commencing the phytoremediation process. Seeds from local regions are preferred as these

adapt to the environmental conditions easily (EPA 2000).

5.3.2.3 Climatic Conditions and site Accessibility

Climatic conditions such as temperature, moisture, rainfall and sunlight influence seed germination

and plant growth to a major extent. Thus, as a suitable candidate for phytoremediation, the

adaptability of the plant under climatic variations must be considered (EPA 2000). Consideration of

accessibility to the site is imperative before the commencement of the process as the consumption

of these plants by livestock or general public may lead to severe health consequences. Thus, edible

plants are not usually preferred for remediation (Ghavzan and Trivedy 2005).

Conclusively, phytoremediation is an economic, sustainable and environment friendly process

for soil reclamation. Moreover, the process is catalyzed by natural solar driven pumps and their

associated metabolic processes. It is also environmentally benign as it reduces water losses by

reducing its evaporation, limits soil erosion and prevents run-off that occurs due to heavy rain or

flooding.

5.4 Future Perspectives

Undoubtedly, the phytoremediation technology has proved beneficial over the conventional methods

for soil reclamation. However, there exists a gap between the process and its practical application.

• The strategy has been applied in laboratory and greenhouse tests, but its application extensively

at field studies should be tested.

• Another major problem of the process is the effective extraction, the contaminant is located

shallow enough for the plant roots to reach it, which is not possible in case of each contaminant.

• Longer lifecycle duration of most plants to attain the maturity stage also limits the application

of this process. Nowadays plants with a short lifecycle are being scrutinized to overcome this

problem.

• Extremely high levels of contaminants pose adverse effects on the plants’ growth and may even

led to plant death. Thus, the process is effective only for lower concentrations of contaminant.

References

Abdel-Shafy, H. I. and M. S. Mansour. 2016. A review on polycyclic aromatic hydrocarbons: source, environmental

impact, effect on human health and remediation. Egypt. J. Pet. 25(1): 107–123.

Agarwal, T. 2009. Concentration level, pattern and toxic potential of PAHs in traffic soil of Delhi, India. J.

Hazard.

Mater. 171(1-3): 894–900.