Transport, bioavailability and fate of metals in storm water runoff are investigated by analyzing data collected at three commercial land-use sites in the town of Genoa (Italy): a landside site within the airport area and a tourism and a dry-bulk terminal sites within the port area. The monitoring campaign, carried out from November 2005 to December 2006, provided hydrologic and water chemistry data. Results clearly indicate the difference between airport and port terminal sites in terms of total suspended solids concentration values ranging from 30 mg/l at the airport-landside site to 1 g/l at the dry-bulk terminal site. Findings of metals partitioning investigation indicate that particulate lead seems to dominate the dissolved fraction irrespective of the water quality characteristics such as TSS and pH, while copper and zinc confirm the tendency for a predominant dissolved fraction and such trend seems strongly related to the TSS mass delivery. Metals speciation was simulated using the thermodynamic equilibrium model MINTEQ. Results of this metal complexation model indicate that zinc speciation is strongly dominated by the ionic form, while copper and lead exhibit a higher tendency to form complexes, thus their behavior is related to the ligands concentration associated with the specific land use