Examining the role of <i>Calotropis procera</i> in improving soil properties of an abandoned urban waste dumping site using phytoremediation

Escalating land degradation challenges have led to active soil restoration programs in India to achieve land degradation neutrality by 2030. This study evaluates the phytoremediation potential of Calotropis procera for rehabilitating heavy metal (HM)-contaminated soils at an urban waste-dumping site over two years. Significant improvements in soil physicochemical properties were recorded, with bulk density and electrical conductivity decreasing by ∼1.3-fold and ∼3.7-fold, respectively, indicating reduced compaction and salinity stress. Increased organic carbon by ∼4.7-fold, cation exchange capacity by ∼35%, and NPK by ∼3- to 4-fold reflected improved soil fertility. The soil pollution index declined from severe/high levels to moderate/low levels, with maximum reduction in HMs Cd, Pb, and Cu. Bioaccumulation factor and translocation factor for Cd, Cr, and Ni in roots indicate strong phytostabilization, minimal leaching, and prevention from food chain transfer, whereas higher accumulation of Cu, Zn, and Pb in shoots reflects efficient phytoextraction. The progressive increase in bioaccumulation factors, particularly for Cd (∼4-fold) and Pb (∼3-fold), along with sustained metal uptake for 6–24 months, highlights long-term remediation efficiency. MAI and CBCI indices further validate the detoxification capacity of Calotropis procera, proving it thus to be an effective, non-edible phytoremediator for sustainable reclamation of metal-contaminated soils.