Differences in Heavy Metal Accumulation in Different Medicinal Plants in Association with Lime Application

Abstract

This study examined variation in Cd and Pb uptake among different medi cinal plants grown under the same soil environment together with immobilizing effect of lime to decrease these metals accumulation by the medicinal plants. For this, lime was incorporated into a heavy metal-contaminated soil at 1% followed by cultivation of seven different annual and 5 different biennial medicinal plants. In order for comparison, control soil without lime treatment was included and all the pot trials were carried out four replicates. Cadmium and Pb concentrations in medicinal plant roots grown in the control soil varied between 0.5 and <TEX>$2.8mg\;kg^{-1}$</TEX> for Cd and 3.2 and <TEX>$82.4mg\;kg^{-1}$</TEX> for Pb. The highest accumulation occurred in C. officinale and the lowest in D. batatas. Lime application decreased average Cd and Pb concentrations in the examined medicinal plants from <TEX>$1.3mg\;kg^{-1}$</TEX> and <TEX>$25.7mg\;kg^{-1}$</TEX> to <TEX>$0.6mg\;kg^{-1}$</TEX> and <TEX>$11.9mg\;kg^{-1}$</TEX>, respectively in comparison with those grown in the control soil.