Analytical study on hexavalent chromium accumulation in plant parts of Pongamia pinnata (L.) Pierre and remediation of contaminated soil

Abstract

Hexavalent chromium [Cr(VI)] is a toxic oxidation state of the heavy metal Cr, which has a wide range of industrial applications. Cr-based mining and industrial activities release Cr(VI) as a pollutant into the soil, which is responsible for pollution. Restoration of soil quality in these mining and industrial areas is highly essential for sustainable development and healthy living. The application of plant systems as a sink for the remediation of soil rich in Cr(VI) is a cost-effective technique to control soil pollution. The present study targets Pongamia pinnata (L.) Pierre as a biological sink for the remediation of Cr(VI)-contaminated soil. The analytical study on Cr(VI) accumulation in plant parts of P. pinnata (L.) Pierre and the status of Cr(VI) present in its rhizospheric soil were carried out following the standard methodologies of the American Public Health Association. The results of the analysis are in favor of the steady increase in Cr(VI) accumulation in plant parts of the targeted plant with the increase in its concentration in rhizospheric soil. The novelty of this study focuses on the survival of P. pinnata (L.) Pierre on soil under high Cr(VI) stress conditions and the differential accumulation of Cr(VI) in its vital vegetative parts with the uptake of the toxic metal from the soil to reduce pollution. It is supported by the higher value coefficient of correlation during the uptake of Cr(VI) from polluted rhizospheric soil with its concentration in soils up to 200 µg/g soil. The order of accumulation of Cr(VI) in root > leaf > stem is significant at p = 0.05 and p = 0.01. Further work on this plant species, P. pinnata (L.) Pierre, can make it an elite species for remediation of Cr(VI)-polluted soil.