Assessment of phytoremedial potential of invasive weeds Acalypha indica and Amaranthus viridis

Abstract

In the present study intercropping of two plant species was carried out over a soil contaminated with five heavy metals lead (Pb), cadmium (Cd), chromium (Cr), cobalt (Co) and nickel (Ni). The experimental setup was designed in such a manner that the effluent stream passed intermittently for 60 days through the plant species Acalypha indica and Amaranthus viridis grown on-site after which the species were uprooted and processed further to check the heavy metal concentration in several parts of the plant such as roots, stem, leaves and flowers as well as the soil. The flowers of A. indica accumulated a maximum amount of Pb and least in the stem with a Translocation Factor (TF) of 21.49 and a Bioconcentration Factor (BCF) value of 2 and the highest concentration of Cr in flowers followed by leaves, root and stem regions with a TF of 11.5 and BCF value of 244.59. Co accumulation in A. indica was noted to be maximum in the flowers and least in the stem with a TF of 12.03 and a BCF value of 3.77, while it was highest in the flowers and least in the root with 8.2 and 0.9 TF and BCF values respectively, for Cd, whereas for Ni it was highest in the flowers and least in stem with 18.19 TF and 11.04 BCF. A. viridis accumulated maximum amount of Pb in leaves followed by flowers and least in stem with a TF of 8.64 and BCF of 259.93. It accumulated highest amount of Cr in the leaves followed by flowers, stem and root region with a TF of 10.55 and BCF of 212.49. The leaves of A. viridis accumulated a maximum amount of Co and the least in the stem region with a TF of 7.05 and BCF of 4.95 while the concentration of Cd was highest in leaves and least in roots with 18.37 and 1.61 TF and BCF respectively. A. viridis accumulating trend for Ni was leaves > flowers > root > stem with a TF of 8.15 and BCF of 10.48. Hence as per the values obtained both the species exhibited successful phytoextraction of all the five heavy metals in their aerial parts making both of them good bioaccumulator species.