Uptake of heavy metals by lupin plants in artificially contaminated sand:: Preliminary results

The aim of this study was to investigate the tolerance, uptake and accumulation of several metals of environmental interest by lupin plants. The effects of different metals on those parameters were evaluated individually as well as in groups, since the latter matches more closely real environmental conditions. The chemical form of some metals was also taken into consideration. Lupin plants were grown in different batches of sand artificially contaminated with Pb(II), Cd(II), Cr(III), Cr(VI), CH3Hg+ and Hg(II) (each metal at the 50 mg L-1 level) or their combinations. After 4 weeks of growth, the results indicated that lupins were quite tolerant to Cd(II), Pb(II), Cr(III) and Hg(II) since contamination with those metals did not cause significant weight differences between metal-treated and control plants. On the other hand, the presence of Cr(VI) and CH3Hg+ induced severe signs of toxicity. Metal accumulation in lupins plants was influenced not only by the chemical form of the analyte but also by the co-presence of other metals. Metal concentration in the plants once harvested were found to be 4.9 g kg(-1), 2.3 g kg(-1), 0.4 g kg(-1) and 0.2 g kg(-1) for Cd(II), Hg(II), Pb(II) and Cr(III), respectively. Metals were preferentially accumulated in roots although a fast translocation to shoots was detected for Hg(II).