Recent Trends in Bioremediation of Heavy Metals: Challenges and Perspectives

Abstract

AbstractHeavy metal pollution is a matter of serious concern worldwide. Movement of heavy metals starting from the extraction processes to their applications in a variety of industrial activities, results in their indiscriminate release in the environment. Prolonged exposure to these heavy metals can cause detrimental health effects in human as well as other living organisms. Heavy metals include a class of some highly toxic metals such as, Hg, Cd, Cr, Pb, Ni, Cu, and Zn. that are reported to have cytotoxic, carcinogenic, teratogenic, and mutagenic effects. Since, these heavy metals are nondegradable and have a tendency to accumulate in environment, their removal from aquatic and terrestrial system is required. Bioremediation is one of the promising techniques which can be used to remove these contaminants from water and soil using biological agents, including microorganisms (bacteria, fungi, and microalgae) and plants (phytoremediation). Microorganisms and plants are capable of taking up heavy metals from nature and use these toxic contaminants in their metabolic activities, or convert them to less/nontoxic forms. Thus, the microorganism- and plant-mediated treatment processes are widely accepted since these methods are based on natural mechanisms and also reduce the chances of generation of secondary pollutants as in the case of various conventional processes. This chapter thus studies the various bioremediation techniques for the removal of heavy metal from nature and will discuss the mechanisms of different biological agents used for the transformation of toxic heavy metals. Different methods for the assessment of heavy metals have been discussed for the effective monitoring of contaminants in nature. The review also presents the recent advances in the field of bioremediation in terms of use of plants and their metabolites, plant growth–promoting rhizobacteria and nanoparticles for efficient removal of heavy metals from contaminated sites.KeywordsHeavy metalsContaminationToxicityBioremediationPhytoremediation