ABSTRACT
The rising concern of heavy metals (HMs) toxicity throughout the world is not only due to its detrimental effects on crop production but also to potential health hazards associated with food chain contamination. The natural concentration of heavy metals in the earth's crust does not process any exciting problems unless anthropogenic activities like the industrial revolution, rapid urbanization and application of fungicides, fertilizers and sewage sludge accelerate its concentration to a toxic level. The decontamination of soil polluted with HMs using existing methods (microbial degradation, filtration, etc.) is expensive, inefficient and poses the possibility of future releases, all of which can be overcome with nanomaterials because of their beneficial properties, such as increased surface area, adsorption capacity, reactivity and surface/volume ratio. An emerging way of cleaning up the environment using nanotechnology is nanobioremediation, which uses nanoparticles created by bacteria, algae, actinomycetes, fungi and plants to remove perilous heavy metals from contaminated sites. As stress alleviators, nanoparticles (NPs) are recognized as being able to reduce the mobility of HMs in soil, resulting in their reduction in availability, improved ability of the apoplastic barrier that hinders their translocation, improved plant antioxidant system by boosting the activity of the different enzymes and nonenzymatic antioxidants, mimetic activities of certain NPs as antioxidants and increased secondary metabolites which acts as a potent stress alleviator.
