General Aspects/Case Studies on Sources and Bioremediation Mechanisms of Metal(loid)s 159

techniques have indefinite use, like the production of biodiesel, bioethanol, CO2 fixation, heavy

metals pollution controls and so on. And it is also favorable to treat wastewater and polluted land

because the contaminated site is highly nutrient-rich for some organisms like Ideonella sakaiensis,

a plastic waste degrading bacterium, Sulfurospirillum arsenophilum, Bacillus arsenicoselenatis,

Chrysiogenes arsenatis and Archaea (Pyrobaculum arsenaticum, Pyrobaculum aerophilum) used

for arsenic pollution control of polluted water (/Kudo et al. 2013). Species like Brassica napus can

even control soil heavy metals pollution by cadmium, cobalt and nickel (Boros-Lajszner et al. 2021).

Bioremediation is not a new technique to treat pollution load, but it is a slow process. But from

the future prospective, highly efficient bioremediation techniques need to be developed by advanced

research with the help of bioinformatics, biostatics analyses and other omics approaches helping to

understand the metabolism of microorganisms efficiently. Certain significant aspects that should be

taken care of include: (1) net reduction of pollution in actual and laboratory conditions, that requires

better equipment handling, patience and regular monitoring; (2) studying the possible contributing

factors (abiotic and biotic); and (3) the remediation technology should be cost-effective, reliable

and rapid. Moreover, the endeavor should be made to integrate the phytoremediation method with

bio-energy for the two-fold utilization of plants for phytoremediation and bio-fuel generation on

polluted lands. These methods should be beneficial to the phytoremediation of polluted regions

and concurrently generate sustainable power that can balance the prices that bear on this kind of

methodologies (Mosa et al. 2016).

9.8 Conclusion

Being an eco-friendly technology for heavy metals remediation and organic contaminants,

phytoremediation has a lot of promise. Rhizospheric bacteria and plants have shown the capability

of detoxifying and converting organic pollutants into harmless compounds that may be eliminated

from the soil without accumulating. The above-ground biomass can carry toxic metals, and

plants can then detoxify, translocate, accumulate and recover heavy metals like lead. Although

phytoremediation has excellent potential to be applied to contaminant removal from water,

sediment and soil, it has not been widely commercialized or implemented on a broad basis. Field

implementation of phytoremediation has still not been studied A lack of comprehensive insight into

the uptake mechanism of metals from the soil system to the roots has hampered the commercialization

of phytoremediation for heavy metals and metalloids. Several recent studies have focused on

transcriptomic and proteomic techniques for metal accumulation in plants and elucidating heavy

metal transport. This chapter summarizes the efficient, environmentally sound and cost-efficient

methods for removing metal(oids) from the environment and protecting the ecology.

Acknowledgment

All the authors listed in the chapter have contributed substantially, directly and intellectually to the

work and have approved its publication. The UGC, GOI, New Delhi, is sincerely appreciative of its

support of the NFSC fellowship on behalf of one of the authors, Kumar M.

References

Abhilash, P. C., J. R. Powell, H. B. Singh and B. K. Singh. 2012. Plant-microbe interactions: novel applications for

exploitation in multipurpose remediation technologies. Trends Biotechnol. 30: 416–420.

Adediran, G. A., B. T. Ngwenya, J. F. W. Mosselmans, K. V. Heal and B. A. Harvie. 2015. Mechanisms behind

bacteria induced plant growth promotion and Zn accumulation in Brassica juncea. J. Hazard. Mater. 283:

490–499.

Adlane, B., Z. Xu, X. Xu, L. Liang, J. Han and G. Qiu. 2020. Evaluation of the potential risks of heavy metal

contamination in rice paddy soils around an abandoned Hg mine area in Southwest China. Acta Geochim.

39: 85–95.