Potential of nano-phytoremediation of heavy metal contaminated soil: emphasizing the role of mycorrhizal fungi in the amelioration process

Heavy metal pollution has become a grave environmental problem drawing worldwide attention. Reclamation of polluted land using innovative and ecofriendly way is crucial to restore soil fertility. During the past two decades, various approaches of bio-/phytoremediation are gaining their acceptance to remediate contaminated soil. Recently, the use of reactive nanomaterials for phytoremediation or ‘nano-phytoremediation’ is becoming popular, claiming to improve the phyto-availability of heavy metals and reduce their toxicity through transformation or detoxification. Nanomaterials exhibit distinct properties concerning size, shape, reactivity, and ratio of surface area to volume rendering their potential for a range of applications including remediation of polluted soil environments with heavy metals, chlorinated organic solvents, organochlorine pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. Further, the combination of plants and associated microbes such as rhizospheric bacteria or arbuscular mycorrhizal fungi has the potential to significantly improve the nano-phytoremediation of heavy metal contaminated soil. This review focuses on recent developments on nano-phytoremediation, plant root associated microbes, and their interaction for developing an integrated and efficient nano-phytoremediation strategy for improved soil remediation in general and for soil contaminated with heavy metal. The application of nanomaterials combined with phytoremediation was discussed.