The aim of this study was to obtain an overview of trace element concentrations (Cr, Cu, Ni, Pb, and Zn) in forest soils of Ticino and lower part of valle Mesolcina and to critically assess the measured values with respect to anthropogenic input vs. lithogenic background. Seventy-six sites were selected which represent a broad range of forest sited bedrock material and soil types of Southern Switzerland. At each site, samples were collected from all genetic soil horizons down to a C or B/C horizon. HNO3-extractable concentrations of Cr, Cu, Ni, Pb, and Zn NH4CL-extractable (plant available) concentrations of Pb and Zn in all samples were determined. There were distinct differences in the concentrations measured in the samples from the lowest soil horizons of soils developed on various geological substrates. Concentrations for Cr, Cu, Ni, and Zn were highest in Bündnerschiefer (schistes lustrés) and metabasites whereas Pb was highest in Ortho- and Paragneiss. The lowest concentrations in the subsoils were found in the dolomites group. Therefore, natural background concentrations for Cr, Ni, and party for Cu are often higher than the maximum allowable concentrations according to the Swiss Environmental Legislation (O-SUOLO). […]