Response of Salix alba L. to heavy metals and diesel fuel contamination
Pot experiment was set in a greenhouse in order to determine the physiological response of Salix alba grown on soil co-contaminated with individual and combination of Cd, Ni, Pb-ethylenediaminetetraacetic acid (EDTA) and diesel fuel treatments. EDTA enhanced the uptake of Cd and Ni, whereas the antagonism between Cd, Ni and Pb led to reduced accumulation of Pb. Presence of 5 g/kg of diesel fuel in soil significantly increased toxic influence of applied heavy metals by further reducing plant growth, photosynthetic rate, transpiration rate and water use efficiency. This concentration of diesel fuel also reduced the uptake and accumulation of Cd (soil concentration of Cd was 4.36 mg/kg), while Ni and Pb accumulation (soil concentrations of 118.7 and 186.7 mg/kg) remained at the same level, but with significant reduction of plant growth, thus reducing S. alba phytoextracion potential. At lower applied contaminant concentrations (3 g of diesel fuel/kg and Cd 2.15, Ni 70.8 and Pb 116.1 mg/kg), growth disturbances were low and diesel fuel presence reduced the uptake of Pb only in roots and old leaves, whereas accumulation capacity of Cd and Ni remained unaffected, indicating that S. alba plants have potential for remediation and re-development of co-contaminated sites with moderate levels of polluters.
Key words: Cd, Ni, Pb, phytoremediation, phytoextraction, willow, Salix alba.