Every year Norwegians produce tons of waste by extracting resources, producing products with short lifespans and disposing after the product end of life. This is not a sustainable model for our society, and many countries are taking measures towards a circular economy, where waste materials are continuously reused and recycled. However, hazardous metals present in wastes have the potential to leach into the environment when exposed to precipitation. In this thesis, the leaching behavior of Cu, Pb, Cd and Zn from vehicle fluff, combustibles and waste electronics was studied. Waste fractions from several waste handling facilities in Norway were collected and subjected to a one step batch leaching test at a liquid sold ratio of 10:1. The resulting leachates were analyzed for major and trace elements, anions and other parameters. A geochemical model was developed to estimate the metal species controlling the mobility when leachates enter the environment. Results showed vehicle fluff and waste electronics to leach significant amounts of Cu (1.2 – 2.4 and 0.02 – 41 mg kg-1), Pb (0.01 – 2.2 and 0.01 – 5.2 mg kg-1), Cd (0.01 – 0.18 and ~0 – 0.17 mg kg-1) and Zn (4.4 – 130 and 0.01 – 18 mg kg-1). Combustible wastes leached lower concentrations of metals, at 0.18 – 0.27, 0.01 – 0.1, 0.002 – 0.003 and 0.6 – 3.2 mg kg-1 for Cu, Pb, Cd and Zn, respectively. Modeling showed that 99% of Cu, Cd and Pb were complexed to dissolved organic carbon, while Zn form non organic species like zinc carbonates and free Zn2+. Due to the leaching capacity of these wastes, the technology allowing for improved handling and recycling of waste materials must be in place to avoid uncontrollable metal emissions.