Abstract

Amaranthus dubius is a nutritious leafy vegetable that is widely distributed in Africa, Asia and South America. The rapid growth and biomass makes them one of the highest yielding leafy crops, which may be valuable for phytoremediation. Thus, this study investigates the potential of A. dubius for the hyperaccumulation and distribution of chromium (Cr), mercury (Hg), arsenic (As), lead (Pb), copper (Cu) and nickel (Ni) in the different plant organs. The phytoremediation was calculated by the  bioconcentration factor and translocation factor of plants grown under controlled conditions in a tunnel house. The metal accumulated was investigated using inductively coupled plasma mass spectroscopy (ICPMS). Following exposure to 25, 75 and 100 ppm of Cr, Hg, As, Pb, Cu and Ni respectively for four days, A. dubius accumulates Cr, Hg and Pb at the low concentration (25 ppm) and translocates it to the shoots, but at higher concentrations (75 and 100 ppm) the metal is only stored in the roots. In the case of As accumulation at all concentrations, the metal is translocated to the shoots; Cu and Ni indicate that the metal is stored in the roots mainly. This study indicates that A. dubius has limited potential for the bioaccumulation of Cr, Hg, Pb, Cu and Ni, but is capable of hyperaccumulating of As.

Key words:  Amaranthus dubius, bioconcentration factor, translocation factor, inductively coupled  plasma mass spectroscopy.