Phytoassessment of in situ weed diversity for their chromium distribution pattern and accumulation indices of abundant weeds at South Kaliapani chromite mining area with their phytoremediation prospective.

Abstract

Release of huge quantities of toxic hexavalent chromium (Cr6+) owing to its widespread use in several industrial and mining activities is a major environmental concern in 21st century. The present in situ vegetation analysis at three study sites gives insight on Cr hyperaccumulation potentiality which evaluates the phytoremediation ability of abundant native weeds growing in and around the Cr contaminated effluent discharge site at South Kaliapani chromite mine area, Odisha, India. Moreover, the study measure the relative bioconcentration of chromium in different plant parts with analysis of uptake related phytoremediation indices viz. Bioconcentration factor (BCF), Transportation index (Ti), Translocation factor (TF) and Metal Extraction Ratio (MER) to assess hyperaccumulation potentiality. Vegetation study near mine effluent discharge site (Site-1) reported maximum abundance for Diectomis fastigiata (8.25) followed by Vernonia cinerea (7.6) with Ti values 56 and 657 respectively. In site-2 (uncultivated barren land near site-1), Croton sparsiflorus showed maximum abundance (6.7) followed by Tephrosia purpurea (5.8) with Ti values 95.2 and 87.8 respectively whereas Kyllinga monocephala reported maximum abundance (6.1) followed by Fern sps. (5.9) with Ti values 62.4 and 81.1 respectively in site-3 (a swampy land flooded with chemically treated mine waste effluent). The highest Cr concentrations was recorded in roots of Diectomis fastigiata (2371mg/kg dry matter) and shoot of Vernonia cinerea (5500mg/kg dry matter) indicating their Cr phytoremediation potential. Moreover, the study provides the early indicative tools for detecting native Cr hyperaccumulators growing in an in situ environment with an in situ phytoremediation perspective.