Monitoring polycyclic aromatic hydrocarbons (PAHs) and heavy metals in urban soil, compost and vegetation.

Samples of urban surface soil, composts, leaves from avenue limetrees and grass from park areas of the city of Basel (Switzerland) were analysed for polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Generally, significant lower levels of PAHs (10 times lower) and heavy metals (3-70 times lower) were found in vegetation samples than in composts or soils. The concentrations of PAHs in soil and compost samples were in the same order of magnitude although 10-100-times higher in comparison to data given for rural soils in other studies, whereas heavy metal contents in urban soils and composts were 2-3 times higher than in rural samples. Using multivariate statistical analysis, it was possible to define similarities or special characteristics of single substances or substance groups in a given matrix reflecting their chemical properties and providing information on their specific emission sources.