Phytoremediation- A Green Approach for Soil Decontamination: Concept, Types, Mechanism and Advantages

The agricultural soil has extremely become contaminated with various pollutants. These pollutants arise from divergent sources including agricultural and industrial drainage, erosion and weathering of rocks, and various human activities, especially after the great development in the industrial sector through the latest decades. Such contaminants negatively affect humankind due to their direct or indirect access to the food chain. Hence, their remediation should be highly considered. A number of techniques have been exploited in contaminant elimination including thermal, chemical or combination of both methods, but these methods are expensive and more complicated. Some plants possess a high capability to eliminate pollutants safely and without the need for a lot of expenses, these plants are called hyperaccumulators. Hyperaccumulators can utilize different techniques to decontaminate soils such as phytoextraction, phytostabilization, phytovolatalization, rhizofitration, and phytodegradation. All the techniques used in soil decontamination are called “phytoremediation”, which is essentially affected by soil and metal properties and plant species. Hyperaccumulators are equipped with various mechanisms to counteract toxic metals safely with no toxicity symptoms. The principle buddies in this process are the phytochelatins and metallothioneins which chelate metals by forming complex with them, which is followed by freeing the sensitive sites from polluting metals or vacuolar sequestration of ligand-metal complex. Phytoremediation is a promising approach that can be utilized for contaminant remediation from impacted sites with some limitations. Therefore, attention has been given to develop modern biological and genetic engineering strategies to increase plant detoxification capabilities