Chromium toxicity, speciation, and remediation strategies in soil-plant interface: A critical review

Abstract

In recent decades, environmental pollution with chromium (Cr) has gained significant attention. Although chromium (Cr) can exist in a variety of different oxidation states and is a polyvalent element, only trivalent chromium [Cr(III)] and hexavalent chromium [Cr(VI)] are found frequently in the natural environment. In the current review, we summarize the biogeochemical procedures that regulate Cr(VI) mobilization, accumulation, bioavailability, toxicity in soils, and probable risks to ecosystem are also highlighted. Plants growing in Cr(VI)-contaminated soils show reduced growth and development with lower agricultural production and quality. Furthermore, Cr(VI) exposure causes oxidative stress due to the production of free radicals which modifies plant morpho-physiological and biochemical processes at tissue and cellular levels. However, plants may develop extensive cellular and physiological defensive mechanisms in response to Cr(VI) toxicity to ensure their survival. To cope with Cr(VI) toxicity, plants either avoid absorbing Cr(VI) from the soil or turn on the detoxifying mechanism, which involves producing antioxidants (both enzymatic and non-enzymatic) for scavenging of reactive oxygen species (ROS). Moreover, this review also highlights recent knowledge of remediation approaches i.e., bioremediation/phytoremediation, or remediation by using microbes exogenous use of organic amendments (biochar, manure, and compost), and nano-remediation supplements, which significantly remediate Cr(VI)-contaminated soil/water and lessen possible health and environmental challenges. Future research needs and knowledge gaps are also covered. The review’s observations should aid in the development of creative and useful methods for limiting Cr(VI) bioavailability, toxicity and sustainably managing Cr(VI)-polluted soils/water, by clear understanding of mechanistic basis of Cr(VI) toxicity, signaling pathways, and tolerance mechanisms; hence reducing its hazards to the environment.

Application of thiourea ameliorates drought induced oxidative injury in Linum usitatissimum L. by regulating antioxidant defense machinery and nutrients absorption

“…Researchers are continuously searching for sustainable crop production strategies under the threat of climate change-induced abiotic stresses [ [24] , [25] , [26] , [27] ]. Among these, foliar applications of different natural and synthetic chemicals have been proposed to mitigate abiotic stresses-induced negative impacts on plants [ 28 , 29 ].…”

Enhancing Wheat Crop Resilience to Drought Stress through Cellulolytic Microbe-Enriched Cow Dung Vermicompost

“…Wheat crop is widely grown across diverse agro-climatic conditions, ranging from tropical to subtropical regions, which exposes it to various environmental stresses. Abiotic stresses, also known as environmental stresses, such as extreme temperature, drought, salt-alkalinization, and metal contaminants exert detrimental effects on the growth, development, and physiology as well as biochemical traits in plants. − However, drought is one of the most important environmental stresses restricting the growth and developmental processes and yield of crop plants …”

Design, Synthesis, and Evaluation of Novel Magnetic Nanoparticles Combined with Thiophene Derivatives for the Removal of Cr(VI) from an Aqueous Solution

“…Chromium (Cr), a naturally occurring heavy metal used in industry, is present in the earth’s crust and the oceans. Cr species such as trivalent Cr­(III) and hexavalent Cr­(VI) are considered hazardous due to their high solubility and diffusivity, which allow them to easily penetrate biological membranes . The use of nanomaterials in water treatment is very successful due to their large surface area, high potential surface reactivity, and absorption capacity .…”

“…Cr species such as trivalent Cr(III) and hexavalent Cr(VI) are considered hazardous due to their high solubility and diffusivity, which allow them to easily penetrate biological membranes. 4 The use of nanomaterials in water treatment is very successful due to their large surface area, high potential surface reactivity, and absorption capacity. 5 Through the adsorption process on their surfaces, nanomaterials can be used to remove heavy metals from wastewater.…”