Accumulation of Cu, Pb, Ni and Zn in the halophyte plant Atriplex grown on polluted soil.

BACKGROUND: Three annual Atriplex species-A. hortensis var. purpurea, A. hortensis var. rubra and A. rosea-growing on soil with various levels of the heavy metals copper, lead, nickel, and zinc, have been investigated.
RESULTS: Metal accumulation by Atriplex plants differed among species, levels of polluted soil and tissues. Metals accumulated by Atriplex were mostly distributed in root tissues, suggesting that an exclusion strategy for metal tolerance widely exists in them. The increased concentration of heavy metals in soil led to increases in heavy metal shoot and root concentrations of Ni, Cu, Pb and Zn in plants as compared to those grown on unpolluted soil. Accumulation was higher in roots than shoots for all the heavy metals. None of the plants were suitable for phytoextraction because no hyperaccumulator was identified. However, plants with a high bioconcentration factor and low translocation factor have the potential for phytostabilization. Similarly, the correlation between metal concentrations and translocations in plants (BCFs and TFs) using a linear regression was also statistically significant.
CONCLUSION: Among the plants studied, var. purpurea was the most efficient in accumulating Pb and Zn in its shoots, whereas var. rubra was most suitable for phytostabilization of sites contaminated with Cu and Ni.