SUITMA 2005 Cairo - Soil properties and metals content in three southern European cities : Ljubljana, Sevilla, and Torino
SUITMA 2005 Cairo
| This abstract is about one of the papers of the Properties of unconventional soils theme of the SUITMA 2005 symposium. |
| Mattia Biasioli,i | Encarnacion Diaz-Barrientos,ii |
| H. Grcman,iii | Luis Madrid,ii |
| Borut Vrscaj,iii | Franco Ajmone-Marsan.i |
- i - Di.Va.P.R.A. – Chimica Agraria, University of Torino, Torino, Italy
- iii - Center for Soil and Environmental Science, University of Ljubljana, Ljubljana, Slovenia.
Soils in urban environments differ from natural and semi-natural ones because they are strongly influenced by men. Anthropogenic activities are reflected by an alteration of soil formation process, by a variation of their physical-chemical properties and by the presence of contaminants.
Within the European project URBSOIL, soils from six different European cities were sampled and analysed. In the present work results obtained from the investigation of the soils of Ljubljana (Slovenia), Sevilla (Spain) and Torino (Italy) are reported. These three cities differ widely for size, climate, geography, bedrock, history, social structure and sources of pollution.
Soils were sampled at the depth of 0-10 cm and 10-20 cm. Four different land uses were considered: parks and open spaces, roadsides, ornamental gardens and riverbanks. Soils were characterized and the pseudototal content of Cr, Cu, Ni, Pb and Zn was measured.
The soils from the three cities showed a very close range of pH, this parameter varying from neutral to sub-alkaline. This is supposed to be due to the inclusion of extraneous materials to the soil that could have contributed to increase the pH (bricks, lime, debris from constructions etc.). Particle Size Distribution was highly variable, as the organic carbon content and cation exchange capacity. Torino revealed to be the most contaminated city, showing the highest average values for all the five metals considered, reflecting its important industrial past. However, the high values of Cr and Ni found in the soils from Torino should be assigned to a probable natural origin as ultramaphic rocks are present in the bedrock. The content of Pb resulted very high in the soils of Sevilla and Torino despite its removal from fuels. The content of Zn was high in all the three cities considered. Fairly low concentrations of Cu were found, comparable to those found in natural or semi-natural soils. The concentrations of heavy metals in the soils of the three cities considered for this work often exceeded national legislation limits.
The content of heavy metals, together with the modification of physical-chemical properties, confirms the strong anthropogenic influence on soils in urban environments.
