Aquatic phytoremediation strategies for chromium removal

Abstract

The environment is increasingly becoming contaminated with chromium (Cr) from increased industrial activity, and this is a serious ecotoxicological concern worldwide. Cr causes serious pollution problems and severe health hazards in living beings. To address contamination concerns, many attempts have been made to remove and recover Cr from wastewaters. To cope with Cr pollution, phytoremediation has emerged as economic and eco-sustainable solution to various physicochemical treatments that are expensive and inefficient, especially at low Cr concentrations. A great variety of plants including aquatic macrophytes and hydroponically grown plants are known to assimilate Cr by directly absorbing, precipitating, and concentrating it from polluted aquatic environments. In view of the above, present review examines the viability of phtoremediation as an eco-sustainable technology for remediation of Cr from aqueos environments. Moreover, such plants also act as catalysts for a variety of chemical and biochemical reactions in the rhizosphere. Furthermore, plants reduce the toxic Cr(VI) to nontoxic Cr(III) and serve as a useful tool for Cr detoxification. Low-molecular weight organic acids secreted by many plants may act as natural chelating agents and can play a major role in enhanced phytoremediation of Cr. This review critically evaluates the efficiency of different plants for Cr removal from wetlands, aqueous solutions and wastewaters. Additionally, an in-depth view on various mechanisms involved during bioaccumulation of Cr in plants is also presented. This review explores current scientific progress in the field of Cr phytoremediation from aqueos environments and presents phytoremediation as a sustainable remediation technology for Cr management.