Phytostabilisation-based mitigation of chromium toxicity in the Sukinda Chromite Mining valley, Odisha, India: influence of monsoonal dynamics, overburden mineralogy, and site-specific constraints

Chromium (Cr) contamination is a major environmental concern in chromite mining regions due to its persistence, mobility, and severe ecological and human health impacts. Among its oxidation states, hexavalent chromium is highly toxic, mobile, and carcinogenic, whereas trivalent chromium is relatively less toxic and more stable in soils. The Sukinda chromite mining valley of Odisha (India), which accounts for nearly 97% of India’s chromite production, represents one of the most critically Cr (VI)-polluted mining landscapes globally. Open-cast mining, overburden (OB) dumping, blasting, ore transportation, and processing have resulted in extensive soil, water, and vegetation contamination, leading to long-term environmental degradation. Although several conventional physico-chemical and advanced bioremediation strategies, such as chemical reduction, phytoextraction, rhizofiltration, microbial Cr reduction systems, silico-genomic approaches, and nanotechnological interventions, have been explored under in situ and ex situ conditions, their large-scale field applicability and sustainability remain limited in mining ecosystems. Phytostabilisation has emerged as a promising, eco-friendly, and relatively low-cost and sustainable approach compared to conventional methods aimed at immobilizing hexavalent chromium in soils, reducing its bioavailability, and preventing off-site migration through wind and water erosion. This review critically synthesizes recent phytostabilisation efforts in the Sukinda chromite mining valley, with special emphasis on ecological restoration of OB sites, OB management practices, identification and assessment of pollution-resistant plant species, and evaluation of phytoremediation potential for effective Cr immobilization. The role of soil amendments such as organic matter, biochar, lime, and microbial inoculants in enhancing hexavalent chromium stabilization and plant tolerance is also discussed. By integrating plant-based stabilization strategies with suitable soil management practices, phytostabilisation offers a viable pathway for long-term risk mitigation, ecosystem restoration, and sustainable management of chromium-contaminated mining landscapes.