Phytoremediation of organic pollutants: current status and future directions

Abstract Phytoremediation is the technology based on plants for extraction, sequestration, and/or degradation of environmental contaminants. The process of phytoremediation is a green and nondestructive suitable alternative to widely practiced physicochemical approaches. Plant-based contaminant removal could be directly inside the plant or outside the plant body (explanta). The process of phytoremediation involves different biochemical and physiological mechanisms facilitated by absorption, accumulation, sequestration, transport, and degradation. Furthermore, plants are equipped with the property of metabolizing hazardous organic contaminants into nontoxic or comparatively less toxic forms. Numbers of organic contaminants including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and halogenated hydrocarbons have been targeted for effective remediation by utilization of diverse plant groups. Currently, many experimental investigations have been conducted to develop genetically modified plants and endophytic bacterial strains harboring genes of interest displaying efficient contaminant degradation ability. Although the phytoremediation strategy for cleaning the organic contaminant seems promising with reference to the process cost, assessment, maintenance of soil biological activity, and carbon capture efficiency, the field-scale application has limited success because of changing environmental conditions, slow growth rate, and adaptability under given natural environment. Some of the limitations associated with phytoremediation could be managed through genetic engineering approaches; however, regulatory issues regarding their release under field conditions and very low public acceptance make the process unsuccessful at field scale. Essentially, extensive laboratory investigations are still needed to deploy the phytoremediation strategies for effective contaminant removal. The successful utilization of recombinant DNA technology together with the existing information on plant physiology, rhizosphere microbiology, and root exudates chemistry could be instrumental in gaining deep insights into the process of environmental contaminant removal.