Plastics contain compounds to improve material properties from diverging chemical groups. Since they are not chemically bound to the polymer backbone, additives may leach into the environment. We analyse such chemicals leaching from different polymer types in various environmental relevant matrices and try to follow degradation processes. We combine experimental designs like weathering scenarios with modelling approaches, where we describe the leaching of the individual chemicals from the different polymer types. In addition we characterize the partitioning behaviour of the leachates.