Phytoremediation design based on field scale assessment of chromium uptake by crops and native plants in and around Rania-Khan Chandpur Cr-contaminated site, India.

We designed a phytoremediation plan for the chromite ore processing residue (COPR) site based on the field-scale assessment of chromium (Cr) uptake by plants thriving in Rania and Khan Chandpur villages, India. We performed a series of investigations to: (i) estimate the land use using unmanned aerial vehicles, (ii) collect plant samples for ICP-MS analysis for Cr concentration in their root, shoot, and grain, (iii) develop suitable biomass management strategies for Cr-laden plant biomass. We found the maximum Cr-concentrations of 196.6 mg/Kg and 184.34 mg/Kg in the dry biomass of the root and shoot of Parthenium hysterophorus and Oxalis sp., respectively. Likewise, Cyanodon dactylon, Chrysopogon zizanioides, Cyperus sp., Eclipta prostrata, Alternanthera sessilis, and Prosopis juliflora showed the ability to sequester Cr ranging between 10 mg/Kg-114 mg/Kg from soils. We designed a phytoremediation plan by considering these plants' ability to sequester varying concentrations of Cr from deep-layered soil through their roots. The post-harvested biomass can be used for the production of Cr-free oil and biochar through which upto 96 % Cr can be prevented from re-entering the environment. Our research can support the stakeholders in restoring this site. Furthermore, by leveraging the insights from this research, rural practitioners can actively participate in the co-creation of community-driven phytoremediation projects.