Evaluation of Ornamental Plants as Metals Bioaccumulators in Urban Low Contaminated Soils

The importance of green areas is increasingly considered for the restoration of polluted urban ecosystems. This subject represents an emerging area of research gaining a commercial significance in the field of environmental biotechnology. In this context, phytoremediation appears to be a promising technique for metal soil cleanup especially where the area has little or no alternative uses. Ornamental plants can be used for this purpose in urban design, where both environmental and aesthetical solutions are needed. A two years pilot study for evaluating the suitability of herbaceous ornamental species to evaluate the attitude of some herbaceous ornamental species as metals bioaccumulators in urban low contaminated soils was carried out. The experiment was carried out in Asti (Italy). Eight species and cultivars have been tested: Helianthus annuus L. 'Zebulon', Helianthus annuus L. 'Nano Semplice - Mix', Silene vulgaris (Moench) Garcke, Alyssum argenteum All., Alyssum saxatile L. 'Sulphureum', Brassica juncea L., Pelargonium sp. 'Frensham' and Pelargonium zonale L. Three plots for each species were planted. Physical-chemical characteristics of top soil before and after the experiment were determined. After harvesting, metals contents in plants were measured. Results indicated that metal concentration varied according to the different part of the plants and to the different species and cultivars. Alyssum, Pelargonium 'Frensham' and Helianthus appeared to be the most suitable. The use of phytoremediation techniques in urban soils can be an interesting method to control metals accumulation in time. Further studies are required in order to find new ornamental species useful in urban green areas and to evaluate proper methods for their disposal.