Microplastics in freshwater systems : origin fate and impact : a methodological research work Microplastics are separated from environmental samples based on their electrostatic behavior. They were taken with a continuous flow centrifuge and by sediment cores. The effects of different plastics on Lumbriculus variegatus were determined and whether the plastic types dissolve poisonous additives in the water phase. The results of a sediment contact test show that PVC had a negative effect on mortality with an LC 50 of 1.7 mg g dw. The glycogen content of the surviving worms show that only the increasing concentration of PVC causes a negative effect. Additives were leached of the plastics.<eng>