It is often not even recognizable as such to the naked eye and harbors dangers that cannot yet be accurately assessed: Microplastics are entering the environment in ever greater concentrations and decompose only very slowly. The plastic particles, which are up to five millimeters in size, are dispersed by water and wind. In the meantime, microplastics have already been detected in all ecosystems, from the deep sea to high alpine glaciers. These particles can even get into the brains of mammals, for example. Although there is increasing evidence that the ingestion of microplastics—depending on size, quantity, and composition—could be harmful to organisms, the degree of danger has not yet been conclusively clarified.