Investigation of phytoextraction and tolerance capacity of Calotropis procera for the detoxification of hexavalent chromium, nickel, and lead

Abstract

The aim of the present study is to reveal the phytoremediation capability of Calotropis procera in the selected region of Bandhwari landfills. Results affirmed that the excessive deposition of municipal solid waste changes the physico-chemical parameters of the soil, which may cause soil pollution. The pot experiment was set up for heavy metals (Cr, Ni, and Pb) analysis with three different concentrations (50 ppm,100 ppm, and 150 ppm). Samples were analyzed to assess the plant’s capability for phytoremediation after 42 days. In the current investigation, ICP-MS results revealed that chromium, nickel, and lead concentration is higher than the permissible limit as per WHO. Results showed that the bioaccumulation factor follows the order of Cr > Ni > Pb. The bioconcentration factor and translocation factor are 15.63 mg/kg and 11.36 mg/kg respectively for Calotropis procera and the highest among all other metal concentrations. Peroxidase activity increases with an increase in chromium ion concentration whereas comparatively less increase of peroxidases in different concentrations of lead and nickel. Peroxidase enzyme assay and photosynthetic pigment test were carried out for tolerance estimation and uptake mechanism of Calotropis procera. FTIR data revealed significant levels of chromium complexation and binding to Calotropis procera tissue via hydroxyl and carboxyl groups. Therefore, it can be concluded that Calotropis procera has the efficiency to provide an effective way to handle heavy metal pollution problems and act as an important cost-effective tool for sustainability and conservation of the environment.