Efficiency of white lupin in the removal of mercury from contaminated soils:Soil and hydroponic experiments
Pilar Zornoza , Roc′?o Mill′an , M. Jos′e Sierra , Almudena Seco , Elvira Esteban
DOI:
Received March 31, 2009,Revised July 09, 2009, Accepted , Available online
Volume 22,2010,Pages 421-427
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This study examined the ability of the white lupin to remove mercury (Hg) from a hydroponic system (Hg concentrations 0, 1.25,
2.5, 5 and 10 mol/L) and from soil in pots and lysimeters (total Hg concentration (19.2 1.9) mg/kg availability 0.07%, and (28.9
0.4) mg/kg availability 0.09%, respectively), and investigated the accumulation and distribution of Hg in di erent parts of the plant.
White lupin roots e ciently took up Hg, but its translocation to the harvestable parts of the plant was low. The Hg concentration in
the seeds posed no risk to human health according to the recommendations of the World Health Organization, but the shoots should
not be used as fodder for livestock, at least when unmixed with other fodder crops. The accumulation of Hg in the hydroponicallygrown
plants was linear over the concentration range tested. The amount of Hg retained in the roots, relative to the shoots, was almost
constant irrespective of Hg dose (90%). In the soil experiments, Hg accumulation increased with exposure time and was the greater in
the lysimeter than in the pot experiments. Although Hg removal was the greater in the hydroponic system, revealing the potential of the
white lupin to extract Hg, bioaccumulation was the greatest in the lysimeter-grown plants; the latter system more likely reflects the true
behaviour of white lupin in the field when Hg availability is a factor that limits Hg removal. The present results suggest that the white
lupin could be used in long-term soil reclamation strategies that include the goal of profitable land use in Hg-polluted areas.
