The European Commission’s Joint Research Centre (JRC) has published a report on the Considerations on a Definition of Nanomaterial for Regulatory Purposes (JRC Reference Report EUR 24403 EN), which aims ‘to discuss elements of a definition of the term ‘nanomaterial’ based on a scientific analysis of related issues as well as a review of currently available definitions’. It furthermore aims to ‘provide a practical approach and guidance for a definition aimed for regulatory use’. The report makes specific reference to the European Parliament’s Own Initiative Report, which demands, inter alia, a comprehensive science-based definition of the term ‘nanomaterial’.
The JRC clarifies that the term ‘nanomaterial’ ‘usually refers to materials with external dimensions, or an internal structure, measured in nanometres that exhibit additional or different properties and behaviour as compared to coarser materials with similar chemical composition’. It notes, that ‘[a] definition aimed for regulatory purposes should target a class of material which requires specific attention. Hence, the more specific term ‘particulate nanomaterial’ is considered to be more appropriate since macroscopic materials with internal structures at the nanoscale, also often denoted as nanomaterials, are not of concern in this context’.
The question of ‘true nano-enabled effects’ is clarified by acknowledging that ‘there are intrinsic nanoscale properties which result from the confinement of atoms and electrons within boundaries of a few nanometres. These effects are most dominant at sizes below a few tens of nanometres (less than about 30 nm). They can considerably change fundamental physical material characteristics like the optical, electrical, and magnetic properties of the nanomaterial’.
The report provides a good overview of a number of proposed nanomaterial definitions; after discussion of a number of possible criteria for a definition of ‘nanomaterials’, giving special consideration on the strong need for enforceability of any regulatory definition, the JRC report recommends:
- For a definition aimed for regulatory purposes the term ‘nanomaterial’ in its current general understanding is not considered appropriate. Instead, the more specific term ‘particulate nanomaterial’ is suggested
- The term ‘material’ is proposed to refer to a single or closely bound ensemble of substances at least one of which is a condensed phase, where the constituents of substances are atoms and molecules
- For a basic and clear definition of ‘particulate nanomaterial’, which is broadly applicable and enforceable, it is recommended not to include properties other than size
- For the size range of the nanoscale, a lower limit of 1 nm and an upper limit of 100 nm or higher should be chosen
- The questions of size distribution, shape, and state of agglomeration or aggregation, may need to be addressed specifically in subsequently developed legislation. It is also likely that certain particulate materials of concern that fall outside a general definition might have to be listed in specific legislation
- Additional qualifiers, like specific physico-chemical properties or attributes such as ‘engineered’ or ‘manufactured’ may be relevant in the scope of specific regulations
Follow these links to find out more, or download the full JRC Reference Report.