Nickel in terrestrial biota: Comprehensive review on contamination, toxicity, tolerance and its remediation approaches

Nickel (Ni) has been a subject of interest for environmental, physiological, biological scientists due to its dual effect (toxicity and essentiality) in terrestrial biota. In general, the safer limit of Ni is 1.5 mg g(-1) in plants and 75-150 mg g(-1) in soil. Litreature review indicates that Ni concentrations have been estimated up to 26 g kg(-1) in terrestrial, and 0.2 mg L-1 in aquatic resources. In case of vegetables and fruits, mean Ni content has been reported in the range of 0.08-0.26 and 0.03-0.16 mg kg(-1). Considering, Ni toxicity and its potential health hazards, there is an urgent need to find out the suitable remedial approaches. Plant vascular (>80%) and cortical (<20%) tissues are the major sequestration site (cation exchange) of absorbed Ni. Deciphering molecular mechanisms in transgenic plants have immense potential for enhancing Ni phytoremediation and microbial remediation efficiency. Further, it has been suggested that integrated bioremediation approaches have a potential futuristic path for Ni decontamination in natural resources. This systematic review provides insight on Ni effects on terrestrial biota including human and further explores its transportation, bioaccumulation through food chain contamination, human health hazards, and possible Ni remediation approaches. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Nickel as a dual-acting element in terrestrial biota has raised concerns among environmental and health researchers. Investigation on nickel concentrations in plants, soil, and water resources indicates potential risks to ecosystems and human health. Understanding the distribution and effects of nickel can contribute to the development of effective remediation strategies.