Rhizospheric soil chromium toxicity and its remediation using plant hyperaccumulators

The hyper-accumulation of chromium in its hexavalent form is treated as a hazardous soil pollutant at industrial and mining sites. Excessive accumulation of Cr⁶⁺ in soil threatens the environmental health and safety of living organisms. Out of two stable forms of chromium, Cr⁶⁺ is highly responsible for ecotoxicity. The expression of the high toxicity of Cr⁶⁺ at low concentrations in the soil environment indicates its lethality. It is usually released into the soil during various socio-economic activities. Sustainable remediation of Cr⁶⁺ contaminated soil is of utmost need and can be carried out by employing suitable plant hyperaccumulators. Alongside the plant's ability to sequester toxic metals like Cr⁶⁺, the rhizospheric soil parameters play a significant role in this technique and are mostly overlooked. Here we review the application of a cost-effective and eco-friendly remediation technology at hyperaccumulators rhizosphere to minimize the Cr⁶⁺ led soil toxicity. The use of selected plant species along with effective rhizospheric activities has been suggested as a technique to reduce Cr⁶⁺ toxicity on soil and its associated biota. This soil rectification approach may prove to be sustainable and advantageous over other possible techniques. Further, it may open up new solutions for soil Cr⁶⁺ management at polluted sites.