Enhanced clean-up of lead-contaminated alluvial soil through Chrysanthemum indicum L.

The natural potential of Chrysanthemum indicum L. for the clean-up of lead-contaminated soil was investigated under pot experiment. Maximum applied lead (at 50 mg/kg) caused significant reduction in the plant height (31.71 %), root length (31.15 %) and dry biomass (32.71 and 41.25 % for root and shoot, respectively); however, minimum applied lead (at 10 mg/kg) promoted the growth of plants to some extent, over the respective control pots. Lead concentration in the tissues followed the order as root > shoot > flower. The combinatorial treatment T (16) (50 mg/kg Pb, 0.8 g/kg elemental sulphur and 6 g/kg vermicompost) caused maximum concentration of lead in root, shoot and flower up to the extent of 43.58, 22.45 and 9.62 mg/kg, respectively, leading to the maximum bioaccumulation factor (0.38). However, the combinatorial treatment T (4) (sulphur and vermicompost) showed maximum translocation factor (0.63) and T (12) (20 mg/kg lead, 0.8 g/kg elemental sulphur and 6 g/kg vermicompost) produced maximum remediation ratio (0.153). The combinatorial treatments under lead-contaminated (10-50 mg/kg) soils showed higher remediation efficiency indicating enhanced clean-up of the aforesaid soils through C. indicum L. Applied lead (> 20 mg/kg) altered the chlorophyll-a, chlorophyll-b and carotenoid contents of the plants. Hence, the authors conclude that a non-edible ornamental plant, C. indicum L., is preferred to be safely grown in moderately lead-contaminated soils along with application of elemental sulphur and vermicompost, which will boost the photosynthetic pigments of the plants, leading to enhanced clean-up of the lead-contaminated soil.