Effect of bentonite on heavy metal uptake by amaranth (Amaranthus blitum cv. Pusa Kirti) grown on metal contaminated soil

Abstract

A pot culture experiment was conducted to assess the effect of bentonite application on heavy metal uptake by amaranth (Amaranthus blitum cv. Pusa Kirti). Amendment of soil with bentonite @ 2.5% significantly improved the plant growth by 76.5 and 41.7% in first and second harvest, respectively. The metal concentration of amaranth reduced by 6.5 & 21.2% for Zn, 30.5 & 29.9% for Cu and 34.4 & 40.2% for Ni at first and second harvest, respectively on application of 2.5% bentonite. Amending the soil with bentonite (2.5%) significantly decreased the bioconcentration factor (BCF) of metals by 74 and 28% for Zn, 38 and 36% for Cu, 44 and 34% for Ni at first and second harvest, respectively. The hazard quotient (HQ) for metal uptake through consumption of amaranth was significantly reduced by application of bentonite @ 2.5% as it immobilises heavy metals in polluted soil.