The potential risks of nanomaterials: a review carried out for ECETOC

Nanotechnology is considered by many as the next logical step in science, integrating engineering with biology, chemistry and physics [1]. It derives from the ongoing trend for miniaturisation in technology as described by Moore's Law and combination with other disciplines. Miniaturisation however has its limits and new approaches in manufacturing (bottom-up fabrication) have to be developed to reach anticipated milestones.Nanotechnology can be considered as the application of science that "steps across the limit" of miniaturisation, where" new rules" become valid [2] More specifically, when the dimensions of a piece of solid material become very small, its physical and chemical properties can become very different from those of the same material in larger bulk form. This is one of the hallmarks of Nanotechnology, which can be described as a research area in which this limit of new properties is reached and strategies are developed to exploit the regime of size-controlled properties.In the last couple of years, the term Nanotechnology has been inflated and has almost become synonymous for things that are innovative and highly promising. On the other hand it is also the subject of considerable debate regarding the open question on toxicological and environmental impact of Nanoparticles and nanotubes [3,4]. In this discussion a definition of Nanotechnology and its underlying sectors, applications and markets is important for the purpose of risk assessment and risk communication. Many definitions refer to the length scale (nano) of this new science but not all mention the new functionalities of materials and components at the nanoscale. A commonly-used working definition refers to the size and (changing) properties of materials in the size range between 1 nanometre (10 ) and 100 nm, but this gives rise to many uncertainties and inconsistencies which need to be resolved.Although quite open and abstract the recent definition forwarded by a working group of the Europische