Nanosciences are about discovering, developing, and using materials whose primary particle sizes are frequently within the low nanometer range. These ultrafine particles offer new properties and opportunities. Although nanoparticles have been produced industrially for decades, exposure of living organisms to ultrafine particles has been going on for very much longer as ultrafine particles are frequently emitted during combustion processes. The present contribution considers only engineered nanoparticles, because, although it is hoped that these technical products will be associated with many new applications, only little information is available about their potential adverse effects on environment and health. At workplaces, during manufacturing, in technical applications or in drugs, nanoparticles will, of course, always have "side effects" which will have to be weighed carefully against their benefits, before they are released into the environment. Therefore, more information about their safety and potential hazards is absolutely necessary. Nanoparticles or nanomaterials are already used in food, cosmetics, and many other applications, and the development of new product lines will increase the possibility of exposure to these materials at the workplace. In addition, it is necessary to consider in advance the final fate of products containing nanomaterials and the potential release of the nanoparticles into the surrounding media. Hence, the biological effects of nanoparticles on living organisms and their uptake and transport within cellular systems or the whole organism are important research topics that have to be addressed in time. To estimate the risks associated with the use and manufacture of nanomaterials, extensive research into the whole life cycle of the new materials is necessary, into the ways the material can enter the environment, routes of exposure of living organisms, toxic effects, bioavailability and bioaccumulation.
