Palladium and platinum concentration in soils from the Napoli metropolitan area, Italy: possible effects of catalytic exhausts

Soils from the Napoli metropolitan area (Italy) were evaluated for Pt and Pd concentrations.One hundred andninety-five (195) samples were collected from residual soils and non-residual soils from flower-beds in a 120 km2area on a 0.5 km grid in the downtown-urbanized area and on 1 km grid in suburban zones. The soils -100 meshsize fraction (150 mm) was analyzed for Pt, Pd and 37 other elements by ICP-ES and ICP-MS after aqua regiadigestion.Pt and Pd contents range between -2 and 52 mgykg and between -10 and 110 mgykg, respectively.Alarge number of samples from the metropolitan area were characterized by anomalous values for Pt ()6 mgykg) andPd ()17 mgykg).Non-r esidual soils from flower-beds are located mainly in the urbanized downtown areas subjectto heavy traffic and have higher Pt and Pd contents than residual soils from suburban areas.Geochemical maps showa strong correlation between roads with major traffic flow and high Pt and Pd concentrations.In addition, data frommost of the downtown flower-beds fall within the three-way catalytic converters (TWC) field identified by wEly JC,et al.Envir on Sci Technol; 35:3816–3822x.This suggests that emissions of abraded fragments from vehicle exhaustsmay be the source of the high values and geographic distributions of Pd and especially Pt in urban soils of Napoli.Catalytic converters (PtyPdyRh) have been mandatory for gasoline-powered vehicles in Europe since 1993.Italypermitted the use of non-catalytic motor until January, 2002.This is responsible for the high values for both Pt andPd in the non-residual soils of the urban areas of Napoli. 2002 Elsevier Science B.V. All rights reserved.