Effect of bentonite on arsenic uptake by beet leaf cultivar Pusa Bharti grown on contaminated soil

Greenhouse experiments were conducted to assess the effect of bentonite amendment on arsenic uptakeby beet leaf (Beta vulgaris L. bar. bengalensis Roxb.) cultivar Pusa Bharti. Application of bentonite to thecontaminated soil increased biomass yield from 0.24 (control) to 0.44 g pot⁻¹ @ 0.25% bentonite amended soil (T₃) at first harvest and 0.65 g pot⁻¹ @ 0.5% bentonite amended soil (T₄) after second harvest over the twoyears. The bio-accumulation factor (%) of arsenic varied from 13.60 in control (T₁) to 3.77 (T₃) in soil amendedwith 0.25% bentonite at first harvest and reduced by 62.4% in the second harvest. The hazard quotient wassignificantly reduced below 0.50 because of 0.25 and 0.50% bentonite application after first and second harvest. The arsenic concentration in plants was reduced to 0.49 from 1.77 mg kg⁻¹ in first harvest, while the values were 0.50 and 1.39 mg kg⁻¹ in 0.5% amended and control soil, respectively after second harvest. Importantly, clayamendments effectively reduced the labile arsenic content up to 54.8 and 58.5% in soil during first and secondharvest, respectively. Soil pH was raised significantly only in 0.5% clay amended soil (7.89) as compared tocontrol (6.70) after complete crop harvest. The effect of bentonite application @ 0.25 and 0.5% was statisticallyat par in most of the parameters. Hence, it may be recommended that application of bentonite @ 0.25% may beuseful to reduce the arsenic uptake by beet leaf as well as its immobilization in polluted soil.