The main aim of the project is to carry out a systematic geochemical soil mapping in the areas of Estarreja, Vicdessos, Gardanne and Marseille. Geochemical soil mapping is needed in order to understand the sources, transport, transformations, and fate (including human and ecosystem health) of chemical constituents in the settings of the different Observatoires Hommes-Milieux (OHMs). Geochemical soil maps will be produced by the regional interpolation of element concentration data obtained from samples collected from georeferenced sites and the digital soil maps (DSM) will be made publicly available on the Internet to potential end-users. Elemental concentrations in the soil will be determined using a field-portable X-ray fluorescence spectrometer (FPXRF). Given the multiplicity of anthropogenic sources that are characteristic of urban and industrial environments under study, isotopic studies will be carried out for tracing and quantifying mixed sources of certain potentially toxic elements (PTEs) in soils.