Uptake and translocation of heavy metals by medicinal plants growing around a waste dump site in Pretoria, South Africa

The study investigated the uptake and translocation pattern of trace metals from two different plant species from a waste dump site in Pretoria, South Africa. Datura stramonium is used as an anti-asthmatic treatment and Amaranthus spinosus may either be used as a medicinal herb or consumed as a vegetable. The trace metal contents from different parts of these plants (leaf, stem and root) were determined by the use of ICP-OES. The concentrations of trace metals from the leaves and stems of both plants were in the order Fe>Mn>Zn>Cu>Cr>Ni>Pb. However, from the roots of D. stramonium the concentration were in the order Zn>Mn>Fe>Cr>Ni>Cu>Pb, while from the root of A. spinosus the trend of accumulation was in the order of Fe>Zn>Cr>Ni>Mn>Cu>Pb. From both plants, the concentrations of determined trace metals were in the order roots>leaves>stems. The overall concentration of heavy metals from leaves and stems appeared to be within the limit laid down for safe human consumption (17.35-78.65 mu g/g Fe, 16.84-52.94 mu g/g Zn, 5.65-7.31 mu g/g Cu, 0.51-1.98 mu g/g Pb, 4.36-5.69 mu g/g Ni and 18. 20-33.56 mu g/g Mn). (C) 2011 SAAB. Published by Elsevier B.V. All rights reserved.