The measure of isotopic ratios of metals is a key tool to trace their sources and characterize their fate in the environment. Indeed, the isotopic signature of an element depends on the inherent isotopic signatures of its sources but also of the different processes affecting their speciation, like sorption, precipitation, reduction, etc. The WP2 aims to develop a new protocol for the determination of Ni isotopic signature in environmental samples and to determine the Ni and Fe isotopic signatures of the different compartments of the soil-waste-organism-water continuum.