Workpackage 2.2 aims at characterizing the chemical degradation of water reservoirs including rivers, lakes, groundwater and peatlands by current and historical mining and metallurgical activities. Based on field observations, it will focus on developing approaches for identifying sources of metals and metalloids and unravelling the transport processes that affect their mobility and toxicity, combining different geochemical tools such as chemical speciation and metal(loid) stable isotope systems. In addition, natural contamination of geological origin in water bodies used for human consumption will be studied to better characterize the contaminants and areas/populations at risk. Overall, this information will allow mapping the sources and state of contamination or vulnerability of the main studied water reservoir.