Phytoremedation: An Effective Way to Treat Heavy Metal Contamination- A Review

Abstract

Over the years there has been a drastic increase in heavy metal contamination in the soil due to a number of natural and industrial processes. As these heavy metals are non-biodegradable in nature, they remain in the environment for long periods of time and may infiltrate into the food chain through plants and eventually get accumulated in the human body via biomagnification. Because of their poisonous nature, they pose a major threat to human health and environment. Therefore, the process of cleaning up of this contamination from the environment is of great significance. Phytoremediation, an ecologically viable process, can be a very good mitigation strategy to rid the soil from this heavy metal pollution. Though phytoremediation is not capable of completely removing dangerous pollutants, it has no deleterious effect on the ecosystem as it is an environment friendly, cost-effective, and natural process. Different plants, the majority of which belong to the Brassicaceae family, that are used in the phytoremediation process are referred to as hyper accumulators. The efficacy of phytoremediation can be improved by having deeper knowledge and understanding of different mechanisms contributing to heavy metal accumulation and tolerance in plants. Different mechanisms such as phytoextraction, phytostabilization, phytovolatilization, and rhizofiltration have been employed to reduce contamination of heavy metals in the soil. Among these, the first and second mechanisms are the most dependable. A number of factors are taken into consideration for choosing the most appropriate phytoremediation strategy for soil decontamination. There are a number of factors that influence the phytoremediation process which include the types of contaminants, their characteristics and the selection of plant species. Other factors to consider include climatic conditions, flooding and ageing, the effect of salt on the process, soil variables and the redox potential.