Eco-restoration potential of native metallophytes through multivariate assessment: a case study in Sukinda Chromite Mines, India

Abstract

The Sukinda mining complex, one of the largest chromite deposits globally, is severely affected by heavy metal (HM) contamination, posing acute ecological risks. This study integrates environmental pollution assessment with multivariate analysis (MVA) to identify native metallophytes for eco-restoration of mining-impacted landscapes. From 2023 to 2024, soil and associated vegetation were sampled from contaminated sites, documenting 38 native plant species (36 genera and 21 families). 10 HMs (Cd, Cr, Mg, Pb, Ni, Co, Cu, Fe, Zn and Mn) were quantified by atomic absorption spectrophotometry (AAS). Pollution indices: geoaccumulation index (Igeo), contamination factor (CF), enrichment factor (EF), pollution load index (PLI), and potential ecological risk index (PERI)- indicated Cd, Cr, Pb, Ni, and Cu as priority pollutants. MVA and Hierarchical cluster analysis (HCA) revealed patterns of metal accumulation, inter-metal relationships, and species clustering. Bioaccumulation factor (BAF) for 23 priority taxa (Cr: 9, Pb: 14, Cu: 16, Cd: 1 species) with BAF > 0.5 (accumulators) and > 1 (hyperaccumulators), demonstrating strong adaptability to metal-enriched substrates, and suitability for phytoremediation. The study provides the first documented HM profiles for C. flexuousus, C. martinii, C. zizanioides, C. purpureus, D. montana, S. siamea, J. gossypiifolia, S. glauca, C. umbellata, Anisomeles indica, and V. denticulata, expanding the phytoremediation knowledge base. The integrated framework establishes a pathway from contamination diagnosis to species prioritisation, supporting large-scale eco-restoration. Leveraging native flora offers a cost-effective, sustainable approach to rehabilitate HM-polluted environments, enhance soil health, conserve biodiversity, and inform pilot-scale remediation strategies, including intercropping with priority species for long-term ecosystem conservation.