University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Gerlinde Wieshammer
(2007):
Phytoextraction of Cadmium and Sinc from Contaminated Soils by Salix ssp..
Doctoral Thesis,
BOKU-Universität für Bodenkultur,
pp 63.
UB BOKU
obvsg
FullText
- Abstract:
- The extraction of heavy metals from contaminated soils using metal accumulating plants has been suggested as low-cost, environmentally friendly, in-situ soil remediation method. Willows (Salix ssp.) are known to accumulate enhanced concentrations of heavy metals in their leaves. However willows with metal extraction rates sufficiently large to be applied as soil remediation method remain to be demonstrated. In this thesis the phytoextraction potential of different willow species was tested in two outdoor pot experiments on five long term contaminated soils for the duration of two to three years. The effects of applying microbial treatments to contaminated soils on biomass production and metal accumulation of willows were determined additionally. Further it was investigated whether an intercropping of Salix caprea with the hyperaccumulator Arabidopsis halleri can possibly enhance the phytoextraction potential of willows. Results showed that the investigated willows accumulated extraordinary large concentrations of cadmium and zinc in their leaves. After three vegetation periods a reduction of aqua regia - extractable Cd in the soil by 20% was determined. Significant seasonal variations of metal concentrations in leaves suggest, that harvesting the leaves after the natural fall of leaves in autumn will remove the largest amount of metals from sites to be remediated. The application of microbial treatments enhanced foliar metal concentrations of two willows on one of the investigated soils. Intercropping of S. caprea and A. halleri increased the total uptake of Zn, but did not influence the Cd accumulation. According to the results of these studies phytoextraction of Cd using efficient, metal tolerant and metal accumulating willows such as S. fragilis, S. caprea or S. x smithiana seems promising. To reach practical application of phytoextraction one important next step is the establishment of field experiments to evaluate metal extraction rates under real conditions.